Free Essays on Distorted Sexual Values

Williams 1 Distorted Sexual Values In today’s society it is evident that premarital sex is a common view. This can be due to several reasons. The meaning of sex is different o different people the word sex alone has several connotations it may refer to gender, the reality of our being male or female example â€Å"opposite sex†. It may pertain to erotic awareness and arousal the attraction toward and desire for intimacy with another example sex appeal. The word sex also used to indicate function activity involving the genital organ as in "having sex"(Clarke 230). This causes confusion in the minds of may people in society today. In the comic strip â€Å"Cathy† Cathy Guise- Wite captures the confusion of many in this comic. As the almost but not quite liberated â€Å"Cathy† is getting dressed to go out on a date, she reflects: â€Å"I’m wearing the â€Å"heirloom lace’ of my grandmothers generation †¦with the conscience of my mothers generation †¦coping with the mora ls of my generation†¦ No mater what I do tonight, I’m going to offend myself† (Clark 231). Society as a whole is confused about sex and its sex values. Sex is a gift from the creator, a part of human God given nature and as such it is good. Writers of scripture clearly endorse the celebration of human sexuality. Society must remember, â€Å"sexuality must be expressed according to the makers instructions† (Clarke 233). Sex has been given this view or definition of something that should be used naturally everyday, when ever we want enjoyment (Leone 22). In the world today all that we do is for self-gratification and pleasing one’s desires. This has had a major role on people’s sexual values/ morals. Williams 2 There is a large group of people in society today that hold the belief that premarital sec is helping society. Leone quotes The Humanist to show the views that many have. Physical pleasure ha worth as a moral value. Traditional religious and social v... Free Essays on Distorted Sexual Values Free Essays on Distorted Sexual Values Williams 1 Distorted Sexual Values In today’s society it is evident that premarital sex is a common view. This can be due to several reasons. The meaning of sex is different o different people the word sex alone has several connotations it may refer to gender, the reality of our being male or female example â€Å"opposite sex†. It may pertain to erotic awareness and arousal the attraction toward and desire for intimacy with another example sex appeal. The word sex also used to indicate function activity involving the genital organ as in "having sex"(Clarke 230). This causes confusion in the minds of may people in society today. In the comic strip â€Å"Cathy† Cathy Guise- Wite captures the confusion of many in this comic. As the almost but not quite liberated â€Å"Cathy† is getting dressed to go out on a date, she reflects: â€Å"I’m wearing the â€Å"heirloom lace’ of my grandmothers generation †¦with the conscience of my mothers generation †¦coping with the mora ls of my generation†¦ No mater what I do tonight, I’m going to offend myself† (Clark 231). Society as a whole is confused about sex and its sex values. Sex is a gift from the creator, a part of human God given nature and as such it is good. Writers of scripture clearly endorse the celebration of human sexuality. Society must remember, â€Å"sexuality must be expressed according to the makers instructions† (Clarke 233). Sex has been given this view or definition of something that should be used naturally everyday, when ever we want enjoyment (Leone 22). In the world today all that we do is for self-gratification and pleasing one’s desires. This has had a major role on people’s sexual values/ morals. Williams 2 There is a large group of people in society today that hold the belief that premarital sec is helping society. Leone quotes The Humanist to show the views that many have. Physical pleasure ha worth as a moral value. Traditional religious and social v...

Feeding Problems and Autistic Spectrum Disorder Research Paper

Feeding Problems and Autistic Spectrum Disorder Research Paper Feeding Problems and Autistic Spectrum Disorder Research Paper Evidence Based Practice Articles on Autism and Feeding Problems Autism spectrum disorder is characterized by different forms of difficulties such as verbal and non-verbal communication, repetitive behaviors, and social interactions (Freedman, 2008 p.4). The condition is a learning disorder, and it depicts a development issue in the brain. Children with autism and autistic spectrum disorder find it hard to interact with other children of their age, and when in school, teachers, and other pupils consider the autistic children as â€Å"difficult†. However, autism can be managed very well. Children with autism need nursing care to bring out the best from them. According to a research conducted by Marcus Autism Center, children with autism are at risk of poor feeding and feeding disorder (Woodruff Health Sciences Center , 2013 para.1). It is notable that proper and healthy meals help children to develop mentally by socializing during meals, but autistic children do not experience that. Good nursing practice are needed to ensure that autism does not affect feeding and health of a child. Children with Autism at Considerable Risk of Nutritional Deficits and Feeding Problems The Department of Pediatrics at the Emory University School of Medicine and the Marcus Autism Center were the first institutions to conduct a research on the issue (Woodruff Health Sciences Center, 2013). First of all, it is not clear what causes autism. It may be genetic since the condition runs in families. Scientists have conducted several other researches to determine the brain sections that lead to the condition (Woodruff Health Sciences Center, 2013). The investigation carried out involved using all peer reviewed articles written on autism and feeding problems. A meta-analysis of the peer reviewed articles was conducted by researchers from Emory University and Marcus Autism Center. From the research, they noted that most children diagnosed with the condition have a lower intake of calcium and protein, and also have a high number of other nutritional problems (Woodruff Health Sciences Center , 2013). Some of the feeding problems that children with autism experience include allergies for many food products. Therefore, the nurses should monitor the feeding habits of children, and ensure that the children eat food which is full of nutritional value (Woodruff Health Sciences Center, 2013). Secondly, autistic children also suffer from pica, a condition in which they eat nonfood materials, which is also a feeding and behavioral deficiency that nurses must observe and restrain. The peer reviewed literature meta-analysis did not indicate that feeding disorders in autistic children resulted from the fact that they had a diet with only a few types of food. However, the Marcus Autism Centre researchers subtly indicated that parents of autistic children complained that few foods make up the diets of their autistic children (Woodruff Health Sciences Center , 2013). As a result of this meta-analysis conducted by researchers from Emory University and Marcus Autism Centre, nurses and caregivers of autistic children now have a chance to make the diets of children right by ensuring that they give supplementary nutrients such as proteins and calcium in the form of tablets or injections. The information is essential in making long-term decisions on the management plan for autistic children and the management of other health issues which they have. Another significant impact of the Emory University and Marcus Autism Center research is that the nurses dealing with autistic children can develop a guideline on how to cope with the condition of those children who suffer from autism. Elimination diet has traditionally been used by nurses in coping with the adverse reactions which autistic children have to some types of food, but now it is clear that utilizing the elimination diet strategy could have a malnutrition potential for those involved (Brown-Guttovz, 2008 p.29). This is what drives the nursing community helping the autistic people to determine the best way of dealing with the feeding disorders. The Emory and Marcus Autism Center research was unique and it aimed at improving nursing process for the autistic children. Early Feeding Problems that Indicate Autism Early diagnosis of any condition is beneficial because it helps in determining the right strategies of coping and managing the impacts of the condition. Researchers at the University of Bristol in England noted that children who have feeding disorders are most likely to be autistic (Neale, 2010 Para. 5). This opens a primary method for early diagnosis of ASD (autistic spectrum disorder) which would help in nursing of such children especially in managing their diet and nutrition. According to the study conducted by Golding and his colleagues, children with autism are selective on the food they eat and accept solid foods way later as compared to those who do not suffer from the condition. They are also not easy to feed, and nurses or parents have to struggle to feed them (Land, 2001 p.10). They are slow feeders and accept very few varied diets. Diagnosis should not be entirely dedicated to the feeding habits; hence, the discovery that children are pervasive food refusers or slow feeders, and other factors such as their speech, attention and behaviors should also be scrutinized to determine if they could be suffering from autism (Neale, 2010 para.8). To come to that conclusion, the researchers asked parents to fill questionnaires with information on feeding and dietary habits of their children at different stages in life starting with 6 to 54 weeks, and when the children were at the age of 7, their heights were measured (Neale, 2010 para.8). The information collected from the questionnaires was compared with the information collected on children who have ASD and those who did not have. The patterns of feeding were identified the characteristic of resistance towards change exhibited by autistic children and, hence, found to be very important in early diagnosis of the condition for easy management. SWEAA – A Self-Report Questionnaire Targeting Eating Disturbances within the Autism Spectrum Children with ASD are sometimes thought to be fussy eaters. In many cases, caregivers and parents withhold food from fussy eaters so that they can eat when hungry. With children suffering from ASD, this strategy is dangerous (Karlsson, Rà ¥stam, Wentz, 2013 p.2225). Wentz et.al developed a self reliant questionnaire which people filled to determine how their eating habits were affected by autism. This questionnaire is useful for teenagers and young adults who have autistic spectrum. However, the young adults must have an IQ of over 70 or have no potential for diagnosis of intellectual disability (Karlsson, Rà ¥stam, Wentz, 2013 p.2225). The Swedish Eating Assessment for Autism spectrum disorders (SWEAA) research conducted by Wentz et.al showed that people with ASD prefer food of certain colors and taste. They were also unable to eat because of the inability to eat certain foods and cut at the foods with the utensils provided (Lesinskiene, PÃ… «ras, Kajokiene, Senina, 2002). Thirdly, the traditional setup of the eating place in which there was a sense of sociability was a challenge for people with autism because most of them prefer to do things on their own, but not in a place where there are other people. This indicated that people with ASD could suffer from different other disorders especially related to allergies and phobias, and the best way to handle such cases is by ensuring that these people are well understood (Pinto-Martin, Souders, Giarelli, Levy, 2005 p.164). Secondly, the SWEAA questionnaire is very essential because it helps in knowing the types of foods that the autistic individual does not naturally take so that substitutes are made available for the individual, and the nutritional balance in the body is maintained (Spurgeon, 1967 p.1416). It is quite unhealthy to withhold food for an autistic individual because such an individual may get malnutrition. John 2004 Reflective Model Johns model of reflection is based on five main questions. The cue questions enable an individual to break an issue into several stages including the process, outcomes and experience. In the determination of nursing issues, Johns reflection model was utilized. The breakdown of its application is shown in the discussion below. Description of the Experience At this stage, the knowledge of how autism is manifested in individuals is very important. The investigations conducted all focused on the feeding problems associated with the autistic children and the implications which these children might get from the feeding problems. Children with such conditions also have great potential to lack good social skills, especially those which are acquired during meals. Parents and caregivers of children with this condition understand better how the children behave with food. It was noted that children with ASD usually accepted solid food later in life as compared to their peers. Autistic children are also choosy on the foods they take (Neale, 2010 para.4). The research conducted by Jean Golding and her colleagues also indicated that some were slow eaters, while others were quite troublesome during feeding (Neale, 2010 para.2). In the Emory University and Marcus Autism Center research, an analysis of case recorded about autism and feeding problems were subjected to meta-analysis to come to a conclusion. In the Jean Golding research, parents and caregivers were asked to fill questionnaires which were used in the determination of the impact of autism on feeding, and the SWEAA study involved young adults and teens with ASD. The teens and young adults were required to fill in the questionnaires on their own (Karlsson, Rà ¥stam, Wentz, 2013 p.2226). The information collected from the three empirical researches was subjected to scrutiny and compared to that of feeding behaviors of people without ASD and the difference noted. The Goals and Objectives of the Researches All three researches, the Emory University and Marcus Autism Centre, the Jean Golding headed Bristol University research and SWEAA study, had one main goal and objective which they wanted to achieve. The goal was to determine the extent of feeding problems associated with autism and the consequences they have on health and nutrition of people suffering from the condition, and hence, and secondly, to determine the best nursing strategy which would impacts of autism to the people diagnosed with the condition. It is necessary to keep in mind that they all suffer allergies towards some food, they have a dislike for foods of certain colors, and more importantly, they suffer a low intake of calcium and proteins. These are some of the issues which nurses consider to define the relevant supplements or alternative feeding which can be used. Influencing Factors Age is one of the most important factors influencing the study. If feeding disorders are discovered early, they can be used to diagnose the condition early. Early diagnosis leads to early intervention for children with ASD, including offering substitutes and food supplements in their diet to ensure that the feeding disorders do not affect their health. Secondly, it is notable that early diagnosis of any condition offers the best chance for effective management, and hence, it is beneficial in nursing. Good nursing practice requires the individual to have a guideline for management. What Could Have Been Improved The articles selected for these assignments are all articles which deal with feeding disorders among the autistic children. However, although they are empirical and they give detailed information on the consequences of the disorders among the autistic, it is worth noting that they do not have mathematical representation, which could be essential for quantification. This would have been appropriate and quite beneficial for the study. Research Outcomes There are many issues that an individual can learn from the exercise. First of all, children with autism are not difficult to feed simply because they want to be rebellious, but because they have allergies for some foods. ASD affects some functions of the brain which cause autistic people to be choosy at what they eat or to have repetitive behavior. It is, however, not certain why children with autism have some allergic reactions to some foods since there is not direct connection of the brain functions with the diet. Secondly, it is important to develop a diet which can help in substituting the foods which the autistic children do not like, because it would be even harder to nurse the autistic children if they are in bad health. Lastly, some of the traditional strategies used in managing choosy children cannot be applied to children with autism, and hence, it is important for parents to enlist the help of professional nurses with knowledge and experience in handling such children. If food is denied to force them to eat it when hungry, they may still not take it because they do not refuse to take on their volition, but as a direct response from the brain triggered by color of food, smell or taste as a result of brain function. Conclusion The study involves analyzing three empirical researches on a learning disorder in regards to nursing. The condition chosen is autism, which is a learning disorder and quite challenging in nursing. Three studies have been analyzed and a John 2004 model of reflection used on the three studies. The intention is to help in further understanding of autism and its implications in nursing. If you need a custom research paper written by a professional academic writer dont miss your chance to contact .

Avoidance of Information Technology Project Failure Essay

Avoidance of Information Technology Project Failure - Essay Example Reasons for the project failures and their sufficient deeds for its avoidance are kept in focus while discussions and consultations with project managers and other resources like books and Internet. Â  Being an IT student, keeping only objectives in hand don’t completes my traits. Though it is the world of proofs and proving objectives with the presentations and documentation. Every deliverable clutches some fundamentals of this project. Deliverables until the end of the project will be as per defined: Â  This is the first deliverable that embraces the contents of Information Technology. What is Information Technology? When is it started? Since then how it is improved? What is the status of Information Technology nowadays? What kinds of projects and their importance in the real world? Etc. This document is a small thesis on Information Technology with a little introduction to the real topic. This deliverable accomplishes first three above-mentioned objectives of the project. Â  A sample of professionals is gathered to have a little talk on the topic. Few famous and well-known software houses are being listed. Moreover, to reach these software houses and contact the entire professionals, references are gathered. This list along with the professional names holds their contacts, their references, and a name of people they are referred by. Reason to make them our samples. This deliverable, strengths of our project research and help in the accomplishment of our forth above mentioned objective. Â  This deliverable is a complete document carrying related questions focusing the topic and finding what may be the reasons or strategies to avoid projects to be failed. This deliverable is submitted to get the approval from the supervisor for proceedings. The questionnaire holds both close-ended and open-ended questions related to their experience and professionalism. Â  

Globalisation (Microfinance and Economic Development) Essay

Globalisation (Microfinance and Economic Development) - Essay Example In 1983, the Bangladesh government gave authorization to an independent bank came to be known as the Grameen Bank project. The rural poor borrowers own 90 percent of the shares of Grameen bank while the rest is owned by the government. The bank has 1084 branches currently with more than 12,000 staffs. The bank serves 2.1 million owners and operates in 37,000 villages. The bank considers credit as the right of human. The poor are regarded as the potential entrepreneurs. Women are entitled with most of the loans as they are the ones who struggle not only against poverty but also against social and economic conditions. The bank has the objective of reversing the vicious circle of poverty. Loans were provided to income generating activities in the first place with the belief that they will help the poor to overcome poverty. Loans are provided on the basis of trust and not on any collateral. Microfinance institutions fund the microenterprises. They explain how the standard of living can be raised effectively through incentives for individual initiative. Profits accrue only to those who work. Some microfinance institutions are involved in channelizing the government funding through their systems although the decision making procedures can function without government intervention. The success of the microfinance can be explained by the free market system which points that profits are diverted only to those who are eager or have worked efficiently. Demand conditions may induce the business to expand and recruit more employees. They are of the view that in spite of million successes microfinance has not been able to meet the goals and contribute in economic development. So industrialization in large scale is the only alternative to break the vicious circle of poverty. It highlights the fact that microenterprises produce and market at the local level. They can avoid the operating economic systems which seem to widen the gap between the

Single case design technique Essay Example | Topics and Well Written Essays - 500 words

Single case design technique - Essay Example When a practitioner follows all the steps of EBP, all the inferences required for the case at hand are usually made and deliberated. The practitioner, at this point, has looked at the case and can appraise the intervention used. The posed research question can be solved using single case design technique very effectively. The main reason for the assertion is the nature of the findings expected from any experiment that seeks to answer the question. In order to tell whether an individual has improved from a developmental disorder, such a person is rated individually. This cannot be a group intervention. According to La grow & Hamilton (2000), single case techniques provide nursing practitioners the required practice in assessing the efficacy of a certain intervention on an individual basis. The authors additionally state that such assessment can be done using a controlled experiment that is applicable to a variety of settings. The posed research question, by the virtue of it being called a research question, requires an experimental procedure that will realize application of verbal self-guidance towards correction of developmental disorder. The researcher will then assume ways of testing the viability of the intervention within the course of the experiment. The situation, therefore, fits into the solutions offered by single case design strategies. In the investigation of experimental control in single case research, Newel (1998) examines methods of improving the assessment method. In the article, the author appraises the possibility of applying findings based on a larger sample to the individual demands. Such a large sample can be obtained through conventional five steps of EBP. Basing on Newel’s findings, the inferences made during such a process will hold and the assessment then done on an individual. The highlighted researches and experiments indicate that single case design can be applied

Novel Planar Nanodevices for Chemical Sensing Applications

Novel Planar Nanodevices for Chemical Sensing Applications In recent years, planar electronic nanodevices have attracted much attention due to their simple architecture, ease of fabrication and low cost of manufacture. Such devices address a wide variety of applications in printed and plastic electronics industry. Using this approach a new type of sensor, which is sensitive to different chemicals, has been developed and reported here. By exploiting the unique characteristics of semiconductor asymmetric nanochannels, a highly selective and sensitive planar nano-transistor based chemical sensor has been realised which can discriminate between wide range of chemical compounds in the ambient atmosphere. The active part of the sensor device was fabricated in a single nanolithography step and was tested using variety of chemicals including polar protic, polar-aprotic and nonpolar solvents. The sensing results showed that, all three solvent categories have exhibited unique chemical signature which could be identified with increased or decreased drain current depending on the analyte used. A significant rise in transistor drain current was observed when the device was exposed to polar aprotic solvents compared to polar protic and nonpolar ones. Further it has been noticed that the exposure of the device to polar protic solvents which has hydroxyl (–OH) functional groups in their molecular frame work has shown very high hysteresis in current voltage measurements. In contrast, the device has exhibited very little hysteresis when exposed to polar aprotic and non-polar solvents with later being the minimum of all. The effect of solvent’s polarity on the sensor’s drain current in terms of adsorption and desorption processes has been studied and reported here. Also the effects of water molecules in ambient air and hydroxyl groups on the device hysteresis behaviour have been investigated. As the gas sensing properties of the sensor are related to the chemisorption of gaseous species at its surface, a detailed understanding of the charge transfer in a chemisorption process is very important; hence most of the discussions in this report focus on explaining this complex phenomenon with a special emphasis on the role of surface states during sensing process. All the measurements were performed at room temperature and the responses were found to be very fast, reversible and reproducible over many cycles of vapour exposure and suggested the stability of the device to be very high. The simple, low-cost, multi-chemical sensing device described in this work could be useful for a variety of applications, such as environmental monitoring, sensing in chemical processing plants, and gas detection for counter-terrorism. Nanofabrication and Characterisation 4.1 Introduction Recent advancements in the area of micro/nanofabrication have created a unique opportunity to manufacture nanometer-sized structures with absolute precision that has wide range of applications ranging from electronic, optical, chemical and biological fields. (Springer Handbook of Nanotechnology Bhushan, Bharat (Ed.)  2nd rev. and extended ed., 2007, XLIV, 1916 p. 1593 illus. in color. With CD-ROM., Hardcover ISBN: 978-3-540-29855-7 This chapter will introduce two of such major top-down fabrication techniques namely photolithography and e-beam lithography followed by a brief description on atomic force microscopy and scanning electron microscopes which have been used in this project to fabricate and image the planar nanosensors reported in chapter 5. 4.2 Lithography In semiconductor processing area-patterning techniques are very important. Lithography is a process of transferring patterns from medium to the other ( ampere a. tseng, kuan chen, chii d. chen, and kung j. ma ieee transactions on electronics packaging manufacturing, electron beam lithography in nanoscale fabrication: recent developmentvol 26, no 2, april 2003 pp 141-149). These transferred patterns are then subjected to a development process that selectively removes either the exposed or unexposed resist depending on the resist nature. The positive resist removes the exposed part where as unexposed resist is developed away using negative resists as shown in the figure 4.1. The exposure systems may be any of these; ultraviolet light rays, X-rays, ion beams or electron beams. But this section focuses on the systems using ultraviolet and electron beams as their source. 4.2.1 Photolithography Photolithography is the most common patterning method, by which the shape and critical dimensions of a semiconductor device are transformed onto the surface of the wafer (got from lecture notes titled photolithography sly). This is the technique used to define the mesa structures and metallic contacts of the device described in this thesis. A photo sensitive resist is spun on to the substrate and exposed through a mask which transfers the patterns on the sample by means of UV light. Then the sample is developed to get the desired pattern as shown below. Figure 4.1. Typical photolithography process. The substrate (A) is  ¯rst coated by photoresist (B) and then exposed by UV radiation through a mask (C). The latent image is either removed (D) or  ¯xed (E) by a developer solution. Source : M. J. Madou, Fundamentals of microfabrication, 2nd ed., CRC Press (2002), p. 19. 4.2.2 Metal film deposition In order to perform electrical measurements on the device, we need to define the metal patterns, through which it can be connected to the electrical probe station.  So two contacts are formed, ohmic and schottky contacts through a process called lift off as shown in the figure 4.2. The GaAs substrate is coated with photoresist and the patterns are defined by photolithography. First the metal film is thermally evaporated and the unwanted metal laying on the resist is lifted off by dissolving the photoresist in acetone. To facilitate the ‘lift off’ of technique, photoresist edges with undercut profiles are desirable. This can be achieved by the treatment of photoresist with chlorobenzene before the UV exposure. Chlorobenzene swells inside the photoresist and makes its â€Å"skin† harder. After the exposure and the development, the profile of the photoresist edges forms an undercut [M. J. Madou, Fundamentals of microfabrication, 2nd ed., CRC Press (2002), p. 19. an d M. Hatzakis, B. J. Canavello, and J. M. Shaw, IBM J. Res. Develop. 24, 452 (1980).,], as shown in Fig. 3.3E. Source fundamentals of micro fabrication book Figure 4.2. Typical lift-of process. The substrate (A) is coated by photoresist (B) and then prebaked to partially dry the solvents (C). A dip in chlorobenzene follows to make the photoresist skin harder. (D) UV exposure through the mask. The edges of the patterns developed into the photoresist after such process show a typical undercut pro ¯le (E). The metal is evaporated onto the sample, forming a thin  ¯lm (F). The unwanted metal is then lifted o ® by dissolving the remaining photoresist in a solvent (G). Ohmic contacts (obeys Ohm’s law, linear I-V) They are essentially formed by a metal layer deposited on a highly-doped semiconductor. Because of the high-doping concentration a very thin Schottky barrier is formed, and the charge carriers, namely electrons and holes, can easily tunnel through. The substrate used in this research work consists of semiconductor heterostructures in which a two-dimensional electron gas (2DEG) was confined between undoped GaAs and doped AlGaAs layers. (R. Williams, Modern GaAs processing methods, Artech House (1990), Chapter 11.) The choice of metals for any given application will depend on conductivity, thermal stability, adhesion, nature of electrical contact with semiconductor (work function/barrier height), and ease of patterning. (got it grom sly lecture notes) A thin layer (~ 45-50 nm) of Au/Ge/Ni alloy which is the most common scheme for making alloyed ohmic contacts to n-type GaAs is used for this work and was evaporated onto the substrate surface at temperatures higher than 360 °C. In this alloy, the germanium diffuses into the GaAs and acts as a dopant, while nickel acts as a wetting layer and also assists the diffusion of Ge into the GaAs. Schottky contacts (rectifying, diode like I-V) Depositing a metal film on an undoped, or lightly n-doped, semiconductor whose electronic affinity is lower than the work function of the metal, will form a thick schottky barrier which is typically several hundreds of meV high, and the thermal energy gained by the electrons, about 26 meV at room temperature, is too low to permit thermionic emission over the barrier. (R. Williams, Modern GaAs processing methods, Artech House (1990), Chapter 12). When a bias is applied to the metal, the height of the energy barrier seen by the electrons injected from the metal into the semiconductor does not change, being fixed by the metal work function and the electronic affinity of the semiconductor. On the other hand, the barrier seen by the electrons injected from the semiconductor into the metal is increased/decreased by a negative/positive bias. This mechanism is responsible for the well-known rectifying effect observed in Schottky junctions [V. L. Rideout, Thin Solid Films 48, 261 (1978). [8] A. M. Cowley and S. M. Sze, J. Appl. Phys. 36, 3212 (1965).]. At negative biases, the Schottky junction essentially behaves like a capacitor: in substrates with embedded 2DEGs, it can be utilised as a gate electrode to modulate the 2DEG carrier concentration, e.g., for the fabrication of field-effect transistors. 4.2.2 Electron beam lithography (EBL) One of the modern approaches in dealing with nanoscale structures is e-beam lithography in which, electrons are accelerated by very high voltage, typically of 10s of kV and then focused onto a layer of polymer to create very fine patterns. EBL provides much higher resolution and more precise than photolithography or x-ray lithography: patterns with feature sizes well below 20 nm can be achieved in modern systems. EBL does not require the fabrication of masks as in the photolithographic process. There are two methods to expose e-beam on to the substrate surface (Rainer waser (Ed.) nanoelectronics and information technology, WILEY-VCH chapter 9, pp 234-236) 2005. Direct writing Projection printing Direct writing is the most common EBL approach and used for fabrication of the device reported here. In this approach, a beam of electrons directly impinges on the resist to form the pattern in a serial fashion. As shown in the figure 4.6, a direct writing system consists of a source of electrons, a focusing optics set, a blanker to turn on and off, a deflection system for moving the beam, and a stage for holding the substrate. Where as projection printing is used to project entire pattern simultaneously on to the wafer and can be divided into two ways; SACLPEL (scattering with angular limitation in projection electron beam lithography) and PREVAIL (projection reduction exposure with variable axis immersion lenses). However we will only concentrate on direct writing technique. Fig 4 dose test patterns of an array of self switching diodes (SSDs) fabricated using e-beam direct write. System configuration Figure 4.1. Simplified structure of a SEM column. The blue lines show the trajectory of the electrons. 4.2.4 E-beam process and proximity efect To perform electron beam lithography, PMMA (polymethyl methacrilate) resist was used which can be chemically changed under exposure to the electron beam. Final resolution of patterns in the e-beam resist and their eventual transfer into the substrate can be affected due to the imperfections in electron optics, the magnetic environment interaction, the overall thermal stability, the interaction between the beam and the substrate all play an equally important role in determining the ultimate system performance. When the electron beam strike the polymer film or any solid material, it losses energy via elastic and inelastic collisions collectively know as electron scattering. Elastic collisions change the direction of electron scattering, where as inelastic collisions lead to energy loss. As the electrons penetrate though the resist into the substrate, some of them undergo large angle scattering leading to undesired exposure that form backscattering. This causes additional exposure in the resist and is known as proximity effect. The magnitude of electron scattering depends on the density of the resist and substrate as well as the velocity of the electrons or the accelerating voltage (guozhong cao, nanostructures and nanomaterials, imperial college press, 2004, pp 280-300). (m.a. McCord and m.j.rooks, handbook of microlithoghraphy, micromachininbg and microfabrication, p.rai-choudary, Ed. Bellingham, WA:SPIE Optical engineering, 1997, ch 2, pp 139-249). The proximity effect is more severe in dense patterns, particularly when the separation between adjacent structures is less than 1ÃŽ ¼m. Since the amount of backscattered electrons depends on the substrate material, a dose calibration is necessary each time different substrates and resist thicknesses are used. Electron Scattering in Resist and Substrate The scattered electrons also expose the resist! Electrons, resist and substrates The smallest thing you can write with the ebeam depends on a large number of factors. These are the spot size used, the type of resist used, the thickness of the resist, the density of the features and the substrate material. When electrons are used to expose a pattern in resist it is not a simple process. Electrons enter the resist and hit the atoms of the resist, these will either forward scatter or back scatter. Backscattered electrons from the resist will leave the resist and, in general, do not contribute to the resist exposure, forward scattered electrons continue into the resist and contribute to the exposure. The thicker the resist the larger the forward scattering and the lower the resolution. High energy electrons (in our case 100kV) will go through the resist and deep into the substrate. Here they will again get scattered and will forward and backscatter. In this case the forward scattered electrons will be moving away from the resist and don’t contribute to the exposure, backscattered electrons from the substrate have a large contribution to the exposure. The higher the energy of the incoming electrons the deeper they will penetrate into the resist and hence the contribution to the resist exposure will be reduced. In the figure below you can see that going from 10kV to 20kV increases the penetration depth of the electrons from 1 µm to around 6 µm. At 100kV the penetration depth in Silicon is around 100 µm Figure schematic diagram of inter proximity effect and intra proximity effect The smallest feature sizes that can be achieved are when the features are isolated from one another. As you make your features closer together the backscatter from the neighbouring features will all contribute to the exposure and it will become harder to find the correct dose to correctly expose all your features. This is call proximity effects. There are 2 main effects of this; inter-proximity and intra-proximity. With inter-proximity when two features are close together the electrons from the exposure of on shape contributes to the dose of the neighbouring pattern. The larger and closer the features the worse this effect. With intra-proximity the dose in the centre of the pattern is larger than at the edges, and especially the corners. This is simply a geometric effect as there are less electrons contributing to the dose in the corners of the shape. The electrons need a path to ground. If you are using a conducting (or semi-conducting) substrate the contact with the holder is sufficient to provide a conducting path. If you are using an insulating substrate (fused glass, quartz) you will need to provide a conductive path for the electrons. This is normally done by evaporating a metal layer on top of the or underneath the resist. Aluminium or Chrome is are often good choices as they can often be easily be removed without effecting the resist, but you should check the chemical compatibility of your process with the removal procedure. Performing a Meaningful Dose Test Exposing a pattern correctly usually requires performing a preliminary test exposure referred to as a dose test.  In this test, the pattern is repeated several times on a test substrate.  Each repetition is performed at a different dose or set of doses creating a matrix of different exposure conditions.  Once the pattern is developed and pattern transfer has been performed the correct dose can be obtained through inspection in a suitable inspection tool (scanning electron microscopy, atomic force microscope, optical microscope, etc).  There are several issues which can impact the usefullness of a dose test.  Here are some guidelines: Use the same type of substrate. If there are films present on the surface of the substrate us a substrate with the identical film stack. For large arrays of features, shooting the entire array as a test is not an efficient use of time.  However, reducing the size of the array to an unrealistically small extent can give incorrent results during the test due to differences in the proximity effect.    ·Ã‚  Expose your patterns so that they are easy to locate.  For example, do not expose a test pattern consisting of a 500 micron x 500 micron array of 50 nm squares in the middle of a 150 mm wafer.  You will probably never find them.  Including some locating features (large lines or a box surounding the pattern) can help tremendously.  If you are exposing an array of patterns use as small of a repeat vector as possible.  This will make locating the entire array easier and minimize the chances of getting lost when travelling in between adjacent elements of the array. Proximity Effect As an electron from the writing beam strikes the surface of a substrate it undergoes various scattering events losing energy and causing the generation of secondary electrons.  The energy range of most secondary electrons falls between 1  and  50 eV.  Secondary electrons that are close to the substrate/resist interface are actually responsible for the bulk of the actual resist exposure process.  While their range in resist is only a few nanometers they create what is known as the proximity effect.  Simply put, the proximity effect is the change in feature size of pattern features as a consequence of nonuniform exposure.   While the dose from the primary beam may be uniform across an entire pattern, the contribution of secondary electrons from the substrate may differ depending on pattern geometry.  Two adjacent features will contribute a background dose of secondary electrons to each other resulting in a higher effective dose.  This causes a broadening of the exposed features.  This is particularly apparent with dense features (e.g. gratings).  Consequently, dense arrays of features may require significantly less dose from the primary beam to print correctly.   Pattern size can also be adjusted to compensate for this effect.  For example, 100 nm lines 100 nm apart are typically drawn in CAD as 90 nm lines 110 nm apart to get them to print correctly.  This strategy stops working at the edges and corners of patterns.  This sometimes requires the  the creation of dummy patterns or devices outside of the primary pattern region to get the main features of interest to print correctly.  One common practice is to draw a box around the pattern to normalize the dose in the primary pattern region. 4.3 Imaging nanostructures Characterisation and manipulation of individual nanostructures requires not only extreme sensitivity and accuracy, but also atomic-level resolution that leads to various microscopes that will play a central role in characterisation and measurements of nanostructured materials (guozhong cao, nanostructures and nanomaterials, imperial college press, 2004, pp 280-300). Nevertheless, when we think of microscopes, we think of optical or electron microscopes that can image an object by focusing electromagnetic radiation, such as photons or electrons, on its surface and gives the image with very high magnifications.   However, the images obtained with these microscopes can only provide the information in the plane horizontal to the surface of the object and do not give any information in vertical dimensions of object’s surface height and depth. This section deals with the imaging of surface topography and surface property measurements of planar sensor using AFM and SEM techniques, which can provide us with all necessary information in both horizontal and vertical planes. (www.afmuniversity.org/pdf/Chapter_1_.pdf pp 1-16) 4.3.1 Atomic force microscopy (AFM) AFM is a very high-resolution type of microscope from the family of scanning probe microscopy (SPM) with the resolutions thousand times the better than optical diffraction limit (http://en.wikipedia.org/wiki/Atomic_force_microscope). Unlike traditional microscopes, AFM does not rely on electromagnetic radiation to create an image. AFM is a mechanical imaging instrument that measures the three dimensional topography as well as physical properties of a surface with a sharpened probe. ((www.afmuniversity.org/pdf/Chapter_1_.pdf pp 1-16) AFM Basic principles It consists of very sharp tip attached to cantilever and is positioned close enough to the surface such that it can interact with the atomic/molecular forces associated with the surface. Then a collimated laser beam focuses onto the cantilever, which scans across the surface such that the forces between the probes remain constant. An image of the surface is then produced by monitoring the precise motion of the probe that can sense the movements as tiny as 0.1 nm. Such high resolution allows to image even single atoms, which are typically 0.5 nm apart in a crystal. Normally the probe is scanned in a raster-like pattern as shown in the figure 4. ((www.afmuniversity.org/pdf/Chapter_1_.pdf pp 1-16) Source : http://www.afmuniversity.org/index.cgi?CONTENT_ID=33 AFM probe: Cantilever and Tip AFM is a force sensor with a sharp tip used to probe the surface. When the tip at the end of the cantilever interacts with the surface, the cantilever bends, and consequently beam path also changes, causing the amount of light in the two photo-detector sections to change. Thus, the electronic output of the force sensor is proportional to the force between the tip and the sample. Tips used for probing the surface is usually made of silicon that have a radius of about 10-20 nm and can be coated by silicon nitride to make them harder, or by noble metals, such as gold and platinum, to locally probe electrical quantities or to induce chemical modifications. Optical detection and Piezo electric scanner In order to detect the cantilever movements, when the AFM is operating in ambient conditions, optical detection is used. Reflected light from the focused laser beam is collected by a photodiode and the cantilever deflection and torsion are detected as a change in the photocurrents of the photodiode elements, as shown in Fig. 4. In the typical AFM configuration the tip is kept still, and the imaging is performed by moving the sample with piezoelectric scanner also referred as piezo tube as shown in the figure 4b. By controlling the bias of one inner and four outer electrodes the piezotube can be moved in three dimensions.  This photosensitive detector measures the change in optical beam position and the change in cantilever height. Feedback control Feedback control is used in AFM for maintaining a  ¬Ã‚ xed relationship, or force, between the probe and the surface. According to the mode used, the feedback loop can be controlled either by the cantilever deflection (contact mode) or by the amplitude of the cantilever oscillation (dynamic modes). The typical feedback system used in contact mode is shown in Fig. 3.11. The feedback control operates by measuring the force between the surface and probe, then controlling a piezoelectric ceramic that establishes the relative position of the probe and surface.  Feedback control is used in many applications; Figure 2-4 illustrates the use of feedback control in an oven. Section 2.3 has a more AFM modes: Tip – sample interactions Depending on separation between tip and the sample a variety of forces can be measured by AFM. At shorter distances van der Waals forces are predominant. Where as these forces become negligible if the tip-sample distance increases.  Forces like electrostatic attraction or repulsion, current induced or static magnetic interactions comes into play at these larger separations. The tip-surface forces (approx.) is given by the following equation Fa = ΔU = 12 B/Z13 – 6A/Z7  attractive Repulsive B and A  are coffecients depend upon the surfaces involved.detectable forces for an AFM 1 nN in the contact regime and 1 pN in the noncontact regime (theory 10-18 N) (r. wiesendanger, â€Å" chapter 11. future sensors.† In h.meixner, r. jones, eds vol 8: micro and nanosensor technology /trends in sensor markets. ) Based on these interactions, AFM usually has two operational modes; contact mode and dynamic mode. Depending on resonant frequency shift of tip-sample, dynamic mode is further divided into tapping mode and non-contact mode. Imaging for this work was carried out in tapping mode. Contact mode Also called as repulsive-static mode, in which, the tip rides on the sample in close with the sample surface (low k). The force produced in the feedback loop is frictional force; hence, the tip might interact with the sample surface. Non-contact mode Also called as attractive-dynamic mode, in which the tip hovers 5-15 nm away from the sample surface. The force generated in the feedback loop is typically van der Waals forces. Applied force (dependent on height z) changes the cantilever oscillation frequency. Figure: AFM Measurement in the figure PSPD represents photosensitive detector. Tapping mode Also called repulsive-dynamic mode, in which the AFM tip taps the surface as it maps the height z. This type of mode eliminates the hysteresis due to the tip sticking on the sample. Also using this method there is less likely to damage the sample. Scanning electron microscopy Scanning electron microscopy is also one of the major techniques for imaging the nanostructures. Although AFM gives high-resolution images with absolute precision, it takes much of time to scan and image the surface area of the sample. Where by SEM can provide an alternative to AFM, which is very fat at imaging the samples in both horizontal and vertical directions. These schematics show the ray traces for two probe-forming lens focusing conditions: small working distance (left) and large working distance (right). Both conditions have the same condenser lens strength and aperture size. However, as the sample is moved further from the lens, the following occurs: the working distance  S  is increased the demagnification decreases the spot size increases the divergence angle  alpha  is decreased The decrease in demagnification is obtained when the lens current is decreased, which in turn increases the focal length  f  of the lens. The resolution of the specimen is decreased with an increased working distance, because the spot size is increased. Conversely, the depth of field is increased with an increased working distance, because the divergence angle is smaller. Comparison between AFM and SEM The AFM is more often compared with the electron beam techniques such as the SEM or TEM. With an AFM, if the probe is good, a good image is measured. (www.afmuniversity.org/pdf/Chapter_1_.pdf pp 1-16) the following comparison between AFM and SEM gives a fair idea of the capabilities for applications A comparison of the some of the major factors follows: FIGURE  1-8 Both  the AFM  and SEM measure  topography. However, both types of microscopes can measure other  surface  physical  properties.  The SEM is good for measuring chemical composition and the AFM is good for measuring mechanical properties of surfaces. Summary This chapter has covered the main processing and imaging techniques used for fabrication of nanosensor reported in chapter 5.  Patterning of metal contacts and mesa structures on to the substrate using photolithography have been discussed in detail. The mechanism for the thin film deposition of Au/Ge/Ni alloy for forming ohmic and schottky contacts have been presented followed by a brief discussion of wet etching for undercut profiles. e-beam lithography which can overcome the resolution limitation in photolithography has been introduced with a description of its basic elements followed a discussion on proximity effect. So overall, this chapter provides the reader with fundamental knowledge to understand the basic fabrication and characterisation process of which serves as a tool for better understanding the fabrication of planar nanodevices discussed in next chapter (i.e chapter 5). Bibliography Introduction The evolution of semiconductor industry has brought a revolutionary change in the way we live today. Right from the invention of germanium transistor in 1947 to the latest sensation graphene transistor, the world has seen some of the spectacular breakthroughs that the human kind had ever imagined few decades ago. In the last fifteen years, more than twelve noble prizes have been awarded for the research based in the field of nanotechnology. 1.1  Sensors and sensor science Life without sensors and sensing would be like an opera without singer or a violin without strings. Such life does not exist. Sensors and sensing, on the contrary, are basic properties of life that are responsible for the closed loop real time control of what is going on inside and how it reacts to the outside situation. From bacteria to plants and animals to human beings, all living organisms use their sensing organs for orientation and communication, for monitoring the environment and for their survival. (sensors and sensing in biology and engineering, springer wien newyork, 2003, friedrich g. barth, joseph a.c. Humphrey, timothy w.secomb pp3-34 chapter1 and 2.) Digital systems however complex and intelligent they are, must receive information from the outside world. Sensors act as an interface between various physical values and electronic circuits that ‘understand’ only a language of moving electrical charges. In other words, sensors are eyes, ears, and noses of silicon chips. Some sensors are relatively simple and some are complex, which operate on fundamental basic principles. Understanding of these devices generally requires an interdisciplinary background in fields such as physics electronics, chemistry etc. Thus, sensors research has brought a unique team of chemists, biologists, physicists electronic engineers, together on one platform, thus making it a truly interdisciplinary field. 1.1.1 The term ‘Sensor’ In this ever-changing world, sensors are becoming ubiquitous in our daily lives and play an important role in this process. Since the early 1990s, semiconductor industry has seen a tremendous growth in the development of variety of sensors. The technological trends in this field have made electronic products not only smaller and sleeker, but also more interactive and powerful.  These sensors with their improving performance–cost ratio will be the key components for the future nanoelectronic devices.(http://www.frost.com/prod/servlet/market-insighttop.pag?docid=140061375) The word sensor is derived from the Latin word sentire, which means, â€Å"to perceive†. A sensor i

Beats as a counterculture Essay -- essays research papers

The Beats As A Counterculture Many of the Beat writers wrote in a style known as spontaneous prose. Allen Ginsberg often writes in this style. He does so in the poem â€Å"Howl† in which he rants and raves about society via his friends – Jack Kerouac, Willaim S. Burroughs, Lawrence Ferlingetti, and Neil Cassidy to name a few, live. He discusses their poverty, civil disobedience, the ways that they fight society, and his personal fight against industrialization; he uses many images in order to allow the reader to understand his lifestyle, the lifestyle of his friends and points of view, specifically their rejection of society. Ginsberg depicts the deprived environment in which he chooses to live in through imagery. For instance the speaker proclaims: â€Å"†¦Dragging themselves through the Negro streets at dawn looking for an angry fix.†(Ginsberg 62) This is a scene depicting an average morning after a night of partying. His friends are trying to make their way back to reality. They search the streets where they have been in Jazz clubs for more drugs so they do not have to â€Å"suffer[ing] Eastern sweats and Tangerian bone grindings and migraines of China under junk-withdrawal†¦Ã¢â‚¬ (Ginsberg 63) Ginsberg is telling of his friend’s addiction and fear of withdrawal. The speaker states: â€Å"†¦Yakketyyakking screaming vomiting whispering facts and memories and anecdotes and eyeball kicks and shocks of hospitals and jails and wars†¦Ã¢â‚¬  (Ginsberg 63) In this passage the speaker of â€Å"Howl† depicts an insane asylum because his mother, himself and many of his friends; specifically Carl Solomon, who the poem is dedicated to, had been admitted or admitted themselves into hospitals.   Ã‚  Ã‚  Ã‚  Ã‚  The Beats were all connected to the reality of poverty. Ginsberg states: â€Å"Who poverty and tatters and hollow-eyed and high sat up smoking in the supernatural darkness of cold-water flats floating across the tops of cities contemplating jazz.†(Ginsberg 62) The obvious image of poverty is when he clearly states â€Å"poverty† but along with this image Ginsberg says â€Å"cold-water flats,† meaning that there was not enough money to have hot water. Another image of poverty is â€Å"who plunged themselves under meat trucks looking for an egg.† They were so desperate for food that they jumped under trucks in search of a single egg. The Beats chose this poverty stricken lifestyle in order to further rej... ...e of a world that no one wants to come. He is using his own version of propaganda to persuade the reader not to support industrialization.. Ginsberg reinforces the second section with the first and third sections. He prepares the reader for a dramatic change from the first to the second section by showing the reader that he is anti-society. By showing that he and his friends are anti-society it is a logical step to say that he is against what society is planning and creating. They are planning and moving toward industrialization. Ginsberg is against industrialization partially for the reason that it is the societal norm to support it. Howl is a poem in which Allen Ginsberg complains about his life and about society. The speaker of the poem describes that he/she and his/her friends reject society and therefore are prone to act in a manner counter to common culture. He explains his points using amazing imagery that allows the reader to see exactly what he/she is writing about. In section two Ginsberg states his complains about industrialization, which was beginning at the time. These ideas are reinforced throughout the poem. I will forever enjoy these rantings and ravings.