Summary

HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

Expand All
Entries
Topic Review
Semiconductor Device
Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced thermionic devices (vacuum tubes) in most applications. They use electronic conduction in the solid state as opposed to the gaseous state or thermionic emission in a high vacuum. Semiconductor devices are manufactured both as single discrete devices and as integrated circuits (ICs), which consist of a number—from a few (as low as two) to billions—of devices manufactured and interconnected on a single semiconductor substrate, or wafer. Semiconductor materials are useful because their behavior can be easily manipulated by the addition of impurities, known as doping. Semiconductor conductivity can be controlled by the introduction of an electric or magnetic field, by exposure to light or heat, or by the mechanical deformation of a doped monocrystalline grid; thus, semiconductors can make excellent sensors. Current conduction in a semiconductor occurs via mobile or "free" electrons and holes, collectively known as charge carriers. Doping a semiconductor such as silicon with a small proportion of an atomic impurity, such as phosphorus or boron, greatly increases the number of free electrons or holes within the semiconductor. When a doped semiconductor contains excess holes it is called "p-type", and when it contains excess free electrons it is known as "n-type", where p (positive for holes) or n (negative for electrons) is the sign of the charge of the majority mobile charge carriers. The semiconductor material used in devices is doped under highly controlled conditions in a fabrication facility, or fab, to control precisely the location and concentration of p- and n-type dopants. The junctions which form where n-type and p-type semiconductors join together are called p–n junctions. Semiconductor devices made per year have been growing by 9.1% on average since 1978 and shipments in 2018 are predicted for the first time to exceed 1 trillion, meaning well over 7 trillion has been made to date, in just in the decade prior.
  • 1.8K
  • 26 Oct 2022
Topic Review
Law
Law is a system of rules that are created and enforced through social or governmental institutions to regulate behavior. Law is a system that regulates and ensures that individuals or a community adhere to the will of the state. State-enforced laws can be made by a collective legislature or by a single legislator, resulting in statutes, by the executive through decrees and regulations, or established by judges through precedent, normally in common law jurisdictions. Private individuals can create legally binding contracts, including arbitration agreements that may elect to accept alternative arbitration to the normal court process. The formation of laws themselves may be influenced by a constitution, written or tacit, and the rights encoded therein. The law shapes politics, economics, history and society in various ways and serves as a mediator of relations between people. A general distinction can be made between (a) civil law jurisdictions, in which a legislature or other central body codifies and consolidates their laws, and (b) common law systems, where judge-made precedent is accepted as binding law. Historically, religious laws played a significant role even in settling of secular matters, and is still used in some religious communities. Islamic Sharia law is the world's most widely used religious law, and is used as the primary legal system in some countries, such as Iran and Saudi Arabia. The adjudication of the law is generally divided into two main areas. Criminal law deals with conduct that is considered harmful to social order and in which the guilty party may be imprisoned or fined. Civil law (not to be confused with civil law jurisdictions above) deals with the resolution of lawsuits (disputes) between individuals or organizations. Law provides a source of scholarly inquiry into legal history, philosophy, economic analysis and sociology. Law also raises important and complex issues concerning equality, fairness, and justice.
  • 12.0K
  • 25 Oct 2022
Topic Review
International Epidemiological Association
The International Epidemiological Association (IEA) is a worldwide association with more than 2000 members in over 100 different countries, who follow the aims of the association to facilitate communication amongst those engaged in research and teaching of epidemiology throughout the world, and to encourage its use in all fields of health including social, community and preventative medicine. These aims are achieved by holding scientific meetings and seminars, by publication of journals, reports, translations of books, by contact amongst members and by other activities consistent with these aims. Members are accepted without regard to race, religion, sex, political affiliation or country of origin. The association publishes its own Journal, the International Journal of Epidemiology (IJE) , which is published bi-monthly, a complimentary copy of which is included in the membership dues. It also sponsors a number of highly reputable publications such as A Dictionary of Epidemiology, and The Development of Modern Epidemiology . In addition, the association organizes The World Congress of Epidemiology (WCE) which is held triennially in different parts of the world. The 19th WCE was held in Edinburgh, Scotland, August 2011, while the 20th WCE will be held in Anchorage, Alaska, August 2014 . Regional Scientific Meetings are also held in the IEA regions during three-year periods between WCEs. The IEA is in official relations with the World Health Organization (WHO) and is run by a council including executive and regional councilors for its 7 regions in addition to the ex-officio members.
  • 845
  • 25 Oct 2022
Topic Review
Informal Methods (Validation and Verification)
Informal methods of validation and verification are some of the more frequently used in modeling and simulation. They are called informal because they are more qualitative than quantitative. Whereas many methods of validation or verification rely on numerical results, informal methods tend to rely on the opinions of experts to draw a conclusion. While numerical results are not the primary focus, this does not mean that the numerical results are completely ignored. There are several reasons why an informal method might be chosen. In some cases, informal methods offer the convenience of quick testing to see if a model can be validated. In other instances, informal methods are the best available option. In all cases though it is important to note that informal does not mean it is any less of a true testing method. These methods should be performed with the same discipline and structure that one would expect in "formal" methods. When executed in such a way, solid conclusions can be made. In modeling and simulation, verification techniques are used to analyze the state of the model. Verification is completed by different methods with the focus of comparing different aspects of the executable model with the conceptual model. On the other hand, validation methods are the methods by which a model, either conceptual or executable is compared with the situation it is trying to model. Both are methods by which the model can be analyzed to help find defects in the modeling methods being used, or potential misrepresentations of the real-life situation.
  • 2.0K
  • 25 Oct 2022
Topic Review
Lifetrack Therapy
Lifetrack Therapy, founded by the Japanese Keio educated and Harvard trained psychiatrist Dr. Yukio Ishizuka, is a new personality model and therapy based on universal spheres of psychological health. Ishizuka's willingness to learn from his patients, as well as his exposure to the East, He draws from the principles of both Zen Buddhism and quantum mechanics in his method of treatment. Ishizuka developed Lifetrack therapy, an approach and methodology to help his patients experience psychological health.
  • 775
  • 25 Oct 2022
Topic Review
Egalitarian Equivalence
Egalitarian equivalence (EE) is a criterion of fair division. In an egalitarian-equivalent division, there exists a certain "reference bundle" [math]\displaystyle{ Z }[/math] such that each agent feels that his/her share is equivalent to [math]\displaystyle{ Z }[/math]. The EE fairness principle is usually combined with Pareto efficiency. A PEEEA is an allocation that is both Pareto efficient and egalitarian-equivalent.
  • 588
  • 25 Oct 2022
Topic Review
Climate-Alliance Germany
Climate-Alliance Germany (German: Klima-Allianz Deutschland) is a network of more than 120 civil society organizations, including environment groups, development groups, churches, organisations from the fields of youth, education, culture and health, as well as trade unions, and consumer associations. Founded in 2007, the aim of the Alliance is to provide a common front to apply pressure to German decision-makers to adopt climate protection measures. Prominent members include WWF, BUND (or Friends of the Earth Germany), and the trade union ver.di. A key issue for the Alliance is the prevention of new coal-fired power plants (the Anti-Coal Campaign). The Alliance wants the German government to phase-out coal (Kohleausstieg) and promote renewable energy.
  • 944
  • 25 Oct 2022
Topic Review
Human Nutrition
Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and good health. Poor nutrition is a chronic problem often linked to poverty, food security, or a poor understanding of nutritional requirements. Malnutrition and its consequences are large contributors to deaths, physical deformities, and disabilities worldwide. Good nutrition is necessary for children to grow physically and mentally, and for normal human biological development.
  • 4.7K
  • 25 Oct 2022
Topic Review
International Date Line in Judaism
The international date line in Judaism is used to demarcate the change of one calendar day to the next in the Jewish calendar. The Jewish calendar defines days as running from sundown to sundown rather than midnight to midnight. So in the context of Judaism, an international date line demarcates when the line of sundown moving across the Earth's surface stops being the sundown ending and starting one day and starts being the sundown ending and starting the following day. However, the conventional International Date Line is a relatively recent geographic and political construct whose exact location has moved from time to time depending on the needs of different interested parties. There are no objective criteria for its placement. In that light, it cannot be taken for granted that the conventional International Date Line can (or should) be used as a date line under Jewish law. In practice, within Judaism the halakhic date line is similar to, but not necessarily identical with, the conventional Date Line, and the differences can have consequences under religious law.
  • 1.1K
  • 25 Oct 2022
Topic Review
Fermentation (Food)
Fermentation typically refers to the conversion of sugar to alcohol using yeast. However, a more appropriate definition would be the chemical conversion of carbohydrates into alcohols or acids. The process is used to produce wine, beer and leavened bread, but fermentation is also employed in preservation to create lactic acid in sour foods such as pickled cucumbers, kimchi and yogurt. The science of fermentation is known as zymology.
  • 1.9K
  • 14 Apr 2023
  • Page
  • of
  • 863

Other Entry Collections

>>