Two main approaches are used in nanotechnology. In the bottom-up approach, materials and devices are built from molecular mechanisms which assemble themselves chemically by principles of molecular appreciation. In the top-down approach, nano-objects are constructed from larger entities without atomic-level power. The impetus for nanotechnology comes from a renewed attention in colloidal science, coupled with a new invention of analytical tools such as the minute force microscope, and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the purposeful manipulation of nanostructures, and led to the observation of novel phenomena.
Friday, December 21, 2007
Nanotechnology
Two main approaches are used in nanotechnology. In the bottom-up approach, materials and devices are built from molecular mechanisms which assemble themselves chemically by principles of molecular appreciation. In the top-down approach, nano-objects are constructed from larger entities without atomic-level power. The impetus for nanotechnology comes from a renewed attention in colloidal science, coupled with a new invention of analytical tools such as the minute force microscope, and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the purposeful manipulation of nanostructures, and led to the observation of novel phenomena.
Monday, December 17, 2007
Inductor
An inductor opposes changes in the current. An ideal inductor would offer no resistance to a constant direct current, however, only superconducting inductors have truly zero electrical resistance. Inductors are used expansively in analog circuits and signal processing.
Thursday, November 29, 2007
Doomguy
All of the computer-game renditions of the Doomguy dress in green armour. Reaper from the film story wears combat gear reminiscent of a S.W.A.T. operative.
Thursday, November 22, 2007
Tourism
Tourism is very important for many countries, due to the earnings generated by the spending of supplies and services by tourists, the assessment levied on businesses in the tourism industry, and the opportunity for employment and financial development by working in the industry. For these reasons, NGOs and government agencies may sometimes sponsor a specific area as a tourist intention, and support the development of a tourism industry in that area.
Tuesday, October 30, 2007
Biography
Ancient Greeks developed the biographical tradition which we have inherited, although until the 5th century AD, when the word biographia first appears, in Damascius Life of Isodorus , biographical pieces were called simply "lives". It is quite likely that the Greeks were drawing on a pre-existing eastern tradition; certainly Herodotus' Histories contains more exhaustive biographical information on Persian kings and subjects than on anyone else, implying he had a Persian source for it.
Monday, October 22, 2007
Calculator
A calculator is a machine for performing calculations. Although modern calculators often incorporate a general purpose computer, the device is calculated for performing specific operations, rather than for flexibility. Modern calculators are more convenient than most computers, though some Pads are comparable in amount to handheld calculators.
Friday, October 12, 2007
Rainbows
The rainbow's exterior is caused by dispersion of sunlight as it goes through raindrops. The light is first refracted as it enters the surface of the raindrop, reflected off the back of the drop, and over refracted as it leaves the drop. The overall effect is that the incoming light is reflected back over a wide range of angles, with the most intense light at an angle of 40°–42°. The angle is self-determining of the size of the drop, but does depend on its refractive index. Seawater has a higher refractive index than rain water, so the radius of a 'rain'bow in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows.
Monday, September 24, 2007
Safety
Safety can be limited in relative to some guarantee or a standard of insurance to the quality and unharmful function of an object or organization. It is used in order to ensure that the object or association will do only what it is meant to do. Normative safety is a term used to explain products or designs that meet applicable design standards. Substantive safety stands for that the real-world safety history is favorable, whether or not standards are met. Perceived safety refers to the stage of comfort of users.
Thursday, September 13, 2007
Table
The data in a table does not have to be actually stored in the database. Views are also relational tables, but their data is considered at query time. In non-relational systems, such as hierarchical databases, the isolated counterpart of a table is a structured file, representing the rows of a table in each record of the file and each column in a record.
Friday, August 31, 2007
Tsunami
A tsunami has a much smaller amplitude (wave height) offshore, and a very long wavelength, which is why they generally pass unobserved at sea, forming only a passing bulge in the ocean. Tsunami have been historically referred to as tidal waves because as they approach land, they take on the characteristics of a vicious onrushing tide rather than the sort of cresting waves that are formed by wind action upon the ocean. Since they are not really related to tides the term is considered misleading and its treatment is discouraged by oceanographers.
Monday, August 20, 2007
Populations
Population growth is varying in population over time. It also can be quantified as the change in the number of individuals in a population per piece time. The term population growth can technically refer to any species, but almost always refers to humans, and it often used easily for the more specific demographic term population growth rate, and is often used to refer specifically to the expansion of the population of the world.
Friday, August 10, 2007
River
From their source, all rivers flow downhill, typically terminating in the sea or in a lake, through a confluence. In arid areas rivers sometimes end by losing water to desertion. River water may also infiltrate into the soil or pervious rock, where it becomes groundwater. Excessive abstraction of water for use in commerce, irrigation, etc., can also cause a river to dry before success its natural terminus.
Tuesday, July 31, 2007
Market
In economics a financial market is a device that allows people to easily buy and sell financial securities, commodities, and other fungible substance of value at low transaction costs and at prices that reflect capable markets. A stock market is a market for the trading of company stock, and derivatives of same; both of these are securities scheduled on a stock replace as well as those only traded privately.
Tuesday, July 24, 2007
Resistance
The resistance of an object determines the amount of current through the object for a known voltage across the object I=V/R, where R is the resistance of the object, measured in ohms, equivalent to J•s/C2, V is the voltage across the object, measured in volts, I is the current through the object, measured in amperes. In metals, the Fermi level lies in the conduction band giving rise to free transfer electrons. However, in semiconductors the position of the fermi level is within the band gap, closely half way between the conduction band minimum and valence band maximum for intrinsic semiconductors.
Wednesday, July 18, 2007
Security
The word security in general procedure is synonymous with safety, but as a technical term security means that something not only is protected but that it has been secured. A condition that results from the establishment and maintenance of protective measures that ensures a state of inviolability from hostile acts or influences. With respect to classified matter, the condition that prevents unauthorized persons from having right to use to official information that is safeguarded in the benefit of national security.
Thursday, July 12, 2007
Computer file
In most computer files are stored on various type of data storage device, there is a hard disk, from which most operating systems run and on which most store their files. Hard discs are the most ever-present form of non-volatile storage at the start of the 21st century. Where files have only temporary information, they may be stored in RAM. The way a computer organizes, names stores and manipulates files is worldwide referred to as its file system. Nearly all computers have at least one file system.
Thursday, July 05, 2007
Peacock
Wednesday, June 27, 2007
Vehicles
Vehicles are non-living means of moving. They are most repeatedly man-made (e.g. bicycles, cars, motorcycles, trains, ships, and aircraft), although some other means of transportation which are not made by man can also be called vehicles; examples include icebergs and balanced tree trunks. Vehicles may be propelled by animals, e.g. a chariot or an ox-cart. However, animals on their own, though used as a earnings of transportation, are not called vehicles. This includes humans transport another human, for example a child or a disabled person.
Vehicles that do not pass through on land are often called crafts, such as watercraft, sail craft, aircraft, hovercraft and spacecraft. Movement lacking the help of a vehicle or an animal is called locomotion. The word vehicle itself comes from the Latin vehicular.
Tuesday, June 19, 2007
Voltage
Voltage is the difference of electrical potential between two points of an electrical or electronic circuit, uttered in volts. It measures the potential energy of an electric field to source an electric current in an electrical conductor. Depending on the difference of electrical potential it is called extra low voltage, low voltage, high voltage or extra high voltage.
Between two points in an electric field, such as exists in an electrical circuit, the distinction in their electrical potentials is known as the electrical potential difference. This difference is proportional to the electrostatic force that tends to drive electrons or other charge-carriers from one point to the other. Potential difference, electrical potential, and electromotive force are measured in volts, leading to the commonly used term voltage. Voltage is usually represented in equations by the symbols V, U, or E.
Electrical potential difference can be thought of as the capacity to move electrical charge through a resistance. At a time in physics when the word force was used loosely, the potential difference was named the electromotive force or EMF—a term which is still used in confident contexts.
Thursday, June 07, 2007
Anatomical basics of the human lip
The skin of the lip, with three to five cellular layers, is very thin compared to typical face skin, having up to 16 layers. With light skin color, the lip skin contains no melanocyte. Because of this, the blood vessels appear through the skin of the lips, which leads to their notable red coloring. With darker skin color this effect is less prominent, as in this case the skin of the lips contains more melanin and thus is visually thicker.
The lip skin is not hairy and does not have sweat glands or sebaceous glands. Therefore, it does not have the usual protection layer of sweat and body oils which keep the skin smooth, kill pathogens, and regulate warmth. For these reasons, the lips dry out faster and become chapped more easily.
Tuesday, May 01, 2007
flag
The first flags were used to assist military coordination on battlefields and flags have evolved into a general tool for rudimentary signalling and identification, especially in environments where communication is similarly challenging (such as the maritime environment where semaphore is used). National flags are potent patriotic symbols with varied wide-ranging interpretations, often including strong military associations due to their original and ongoing military uses. Flags are used in messaging, advertising, or for other decorative purposes, though at this less formal end the distinction between a flag and a simple cloth banner is blurred. The study of flags is known as vexillology, from the Latin vexillum meaning flag or banner.
Monday, April 30, 2007
Morality
One counter-argument is that because the government is the party performing the act of imposing taxes, and assuming the existence of a democracy, society as a whole decides how the tax system should be organised. The American Revolution's "No taxation without representation" slogan implied this view. The same argument could be made in a monarchy: "since the King embodies the nation, the nation as a whole decides how the tax system should be organised." Substituting the terms "Politburo," "Führer," or "Leader," etc., for the word "King," one can describe the politics of most of the 20th century. Under this view, taxes are paid individually and therefore, to be considered voluntary, in any meaningful way, should be levied only with the consent of the individual.
TEACHING
Monday, April 02, 2007
Bankruptcy
The main reason of bankruptcy is to give an honest debtor a fresh start in life by reducing the debtor of most debts, and to repay creditors in an orderly manner to the extent that the debtor has the means available for payment. Bankruptcy allows debtors to resolve debts through the division of non-exempt assets among creditors. In addition the declaration of bankruptcy allows debtors to be discharge most of the financial obligations, after their non exempt assets are dispersed, even if their debts have not been paid in full.
Monday, February 05, 2007
Personal property
The distinction between these kinds of property is important for a variety of reasons. Generally one's rights on movables are more attenuated than one's rights on immovable. The statutes of restrictions or prescriptive periods are usually shorter when trading with personal or movable property. Real property rights are usually enforceable for a longer period and in most jurisdictions real estate and immovable are registered in government sanctioned land registers. In some jurisdictions, rights can be registered against personal or movable property.