
	Where results make sense

Topic: Impurity

Related Topics

impurity level

In the News (Sat 30 Aug 08)

Gordon Brown

Derby County

Mike Huckabee

Lute Olson

Pearl Harbor

Sonia Gandhi

Ricky Hatton

Narendra Modi

Jesus Christ

Rudy Giuliani

	Impurity - Wikipedia, the free encyclopedia
		Impurities are substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound.
		Impurities are either naturally occurring or added during synthesis of a chemical or commercial product.
		In general impurities are able to serve as initiation points for phase transitions because the energetic cost of creating a finite-size domain of a new phase is lower at a point defect.
	en.wikipedia.org /wiki/Impurity (649 words)

	Doped Semiconductors
		Impurity atomw with 5 valence electrons produce n-type semiconductors by contributing extra electrons.
		Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or electron deficiency.
		The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor.
	hyperphysics.phy-astr.gsu.edu /hbase/solids/dope.html (189 words)

	MICRO:February 1998:Process Equipment—Vacuum Pumps; by Tadahiro Ohmi, (p 53)
		In this manner, the impurity back-diffusion phenomenon could be experimentally investigated by measuring the impurity level, which was defined as the ratio of the partial pressure of back-diffused impurity gas to the total gas pressure in the chamber.
		Figure 8 shows the impurity level, which is defined as the ratio of the partial pressure of helium (the simulated impurity gas) to the total gas pressure in the chamber, as a function of the nitrogen (the simulated process gas) gas-flow rate for three different pumping speeds of the backing pump.
		It is important to note that the impurity (helium) back-stream is completely suppressed even in a high-gas-flow condition where degradation in the TMP performance occurs because of the back-diffusion of the nitrogen process gas caused by the molecular collisions in the front blades, as previously discussed.
	www.micromagazine.com /archive/98/02/ohmi.html (3195 words)

	An impurity accumulation density window in long-pulse LHD discharges (Site not responding. Last check: 2007-10-09)
		Impurity control is one of the important issues for realizing a fusion reactor.
		The impurity emission increases because of the reduction of the electron temperature, in spite of the decrease of iron density in the central region.
		When impurities enter in the PS regime, they are screened by the dominant contribution of the temperature gradient term on account of the flat density profile and the parabolic temperature profile, which are usually observed in LHD plasmas.
	www.ornl.gov /sci/fed/stelnews/sn81/sn81.html (2484 words)

	Bryn Mawr Classical Review 2004.12.06
		She suggests that the two types of impurity associated with intermarriage in the Hebrew Bible (moral and genealogical) continue to serve as the basis for post-biblical prohibitions of intermarriage.
		In the last section of this chapter, H. discusses the ritual impurity of idols, with the aim of refuting Alon's assertion that Gentile ritual impurity is a pre-rabbinic halakhah rooted in the impurity of idols.
		She defines genealogical impurity as the "distinguishing characteristic of Jewish identity" (p.193) and surveys the adoption of this ideology in biblical, Second Temple, and rabbinic sources.
	ccat.sas.upenn.edu /bmcr/2004/2004-12-06.html (2064 words)

	Insulated gate semiconductor device and method of manufacturing the same - Patent 5952699 (Site not responding. Last check: 2007-10-09)
		The impurity regions 110 restrain a depletion layer that extends from a drift region 102 toward a channel formation region 111, and prevents a short channel effect caused by the depletion layer, with the result that an insulated gate semiconductor device high in withstand voltage can be manufactured without lowering the operation speed.
		In particular, in the case where the impurity regions are provided in the form of a linear pattern which is substantially in parallel with the channel direction (a direction along which the carriers move), the impurity regions form side walls that function as rails along which the carriers move.
		The impurity regions 110 may be made of one or a plurality of kinds of elements selected from carbon, nitrogen and oxygen, or boron which belongs to an element of group XIII in case of the n-channel FET as in the present embodiment.
	www.freepatentsonline.com /5952699.html (9791 words)

	Impurity Transport
		Impurities are either released to the plasma via the plasma-wall contact (Be, B, C, O, Si, metals), or produced by the fusion reaction (He) or added artificially (He, N, Ne, Ar) to modify the plasma radiation properties.
		Furthermore, an enhanced impurity concentration was shown to reduce the level of fluctuations and anomalous transport in the plasma edge region, giving rise to an improvement of the overall plasma confinement.
		Apart from the physics issues, a detailed knowledge and control of the impurity content in the plasma is important also for the safety of the plasma device with respect to the load and lifetime of plasma-facing machine components.
	www.fz-juelich.de /ipp/impurity_transport (286 words)

	Method of producing semiconductor device - Patent 4597824
		A doped oxide film in which impurities such as phosphorus and impurities such as arsenic are doped is formed on a semiconductor substrate, and a nitride film is formed in regions where p type pockets are formed on the both sides of a gate electrode.
		Further, with the gate electrode as a mask, n.sup.- type impurity region and p type impurity region are formed, thereafter selectively growing a film on the side walls of the gate electrode to form an n.sup.+ type impurity region with the gate electrode and the film as masks, thus producing a MOS transistor.
		is formed on the surfaces of the impurity regions 225a and 225b, and arsenic in the vicinity of the interface between the platinum layer 228 and the substrate 221 is diffused into the substrate 221 to form impurity regions 230a and 230b having a resistivity of 70 ohm per square and a depth of 0.2.mu.m.
	www.freepatentsonline.com /4597824.html (6132 words)

	United States Patent Application: 0040089892
		The method of manufacturing a trench gate type field effect transistor according to claim 7, wherein an opposite conductivity type impurity layer of a conductivity type opposite to said impurity layer is formed in a section of the substrate deeper than said impurity layer, and the first trench is formed thereafter.
		Further, at an end of the source or the drain, forming an impurity area, commonly referred to as a Halo or a pocket, of an opposite conductivity type by way of methods such as oblique ion implantation or the like to suppress the short channel effect is being attempted.
		Further, in order to form an impurity layer 9, phosphorus, arsenic or the like, which are n-type impurities, is ion-implanted in an area in which a source S and a drain D are to be formed at a concentration of approximately 3.times.10.sup.15 cm.sup.-2 at a depth of approximately 0.1 to 0.2.mu.m (FIG.
	appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1="20040089892".PGNR.&OS=DN/20040089892&RS=DN/20040089892 (4673 words)

	Impurity Profile: A must for quality product - Asia Pharma Expo 2003 - Express Pharma Pulse (Site not responding. Last check: 2007-10-09)
		Impurities below 0.1 per cent are generally not considered still the impurities (Potential) that are expected to be unusually potent, toxic at a level lower than 0.1 per cent shall be identified and eliminated.
		In inorganic impurities specially the carry over of catalyst to drug substance and completion of reaction shall be evaluated during development.
		The method used to determine the impurity must be capable of detection and quantitation of impurities.
	www.expresspharmapulse.com /20030220/asia10.shtml (840 words)

	MALAVAGGO - IMPURITY
		When your impurities are purged and you are free from sin you will reach heaven, the land of the elect.
		Impurity arising from iron eats into it though born from itself, likewise the evil deeds of the transgressor lead him to the evil state.
		Non-recitation is the impurity of the seeker, non-exertion is the impurity of house; indolence is the impurity of (personal) appearance, and thoughtlessness is the impurity of the watchful.
	www.esf.edu /PSE/chatterjee/Dhammapada/MALAVAGGO.htm (596 words)

	ANDAs: Impurities in Drug Substances
		It is important that the rationale include a discussion of the impurity profiles observed in the batch(es) under consideration together with a consideration of the impurity profile of the batch(es) manufactured by the proposed commercial process.
		For impurities known to be unusually potent or to produce toxic or unexpected pharmacological effects, we recommend that the quantitation and/or detection limit of the analytical procedures correspond to the level at which the impurities are expected to be controlled.
		For unidentified impurities to be listed in the drug substance specification, we recommend that you clearly state the procedure used and assumptions made in establishing the level of the impurity.
	www.fda.gov /cder/guidance/6422dft.htm (2307 words)

	ANDAs: Impurities in Drug Substances, Guidance Document
		Organic impurity levels can be measured by a variety of techniques, including those that compare an analytical response for an impurity to that of an appropriate reference standard or to the response of the drug substance itself.
		For impurities known to be unusually potent or to produce toxic or unexpected pharmacological effects, the quantitation and/or detection limit of the analytical methods should be commensurate with the level at which the impurities need to be controlled.
		The summation of impurity levels plus the assay value may be misleading, for example, when the assay procedure is nonspecific (e.g., potentiometric titrimetry) and the impurity level is relatively high.
	www.fda.gov /cder/guidance/2452fnl.htm (4407 words)

	Yadayyim01
		Apart from ritual impurity contracted through the 'supreme primary source' (which required the ashes of the red heifer as explained) human beings and untensils could be purified by the waters of a Mikveh [ritual bath].
		I originally likened ritual impurity to a contagious disease, in that it is deemed to be passed on from one person to another (and from one object to another and from an object to a person and vice versa) by physical contact.
		Another form of ritual impurity is incurred by a woman when she menstruates; the prescribed mode of removal is bathing in a Mikveh [ritual bath].
	www.bmv.org.il /shiurim/yadayyim/yad01.html (7676 words)

	Tokamak Plasma Spectroscopy at LLNL (Site not responding. Last check: 2007-10-09)
		Impurity ion radiative processes are the most likely mechanism for achieving this operating condition; robust, quantitative predictions of impurity radiative loss rates are therefore essential.
		Impurity ions in a tokamak plasma can also radiate through channels other than electron impact excitation of line emission; we also compute the rate of power loss through line emission fed by dielectronic recombination and continuum emission via radiative recombination and bremsstrahlung.
		The absence in the core of impurity anomalous transport is an important result for this plasma regime of strong auxiliary heating.
	www-phys.llnl.gov /Research/Tokamak (8969 words)

	Impurity Photovoltaic Effect
		Impurities with energy levels somewhere in between the valence and conduction bands of a semiconductor can provide additional stepwise transitions from the valence to the conduction band by the subsequent absorption of two or more photons with energies less than the band gap.
		For a transition from the impurity into the conduction band, however, the impurity should almost be fully occupied.
		The optimal situation for the absorption of all potentially absorbable photons is achieved if one half of the impurity states at each energy level is occupied and one half is empty, allowing transitions into the impurity state and out of the impurity state with equal probability.
	www.esqsec.unibe.ch /pub_96.htm (671 words)

	Nutech Analytical, Inc. - Surimi Impurity Analysis (Site not responding. Last check: 2007-10-09)
		Surimi and kamaboko have been made for centuries by the Japanese and are thought to date as far back as 1100 A.D. The Japanese discovered that mincing fish flesh, then washing and heating it, caused a natural gelling of the pulp.
		In modern commercial surimi processing, fl or grey impurities embedded in surimi are usually caused by fish skin and have a direct impact on the value of the product.
		Impurity count results are displayed for review and archiving.
	www.nutechanalytical.com /spx/surimi.htm (281 words)

	Physics of Impurity Entrainment (Site not responding. Last check: 2007-10-09)
		One of the major issues confronting divertor research is whether or not significant impurity radiation can be obtained in the divertor region while maintaining a relatively clean core plasma.
		In this regard, tools are required that are effective in increasing the impurity enrichment (i.e., the ratio of the divertor concentration to the core concentration).
		However, the scope of these experiments was limited to determining the magnitude of the effect induced by the SOL flow and did not address the relative importance of induced SOL flow with respect to other, possibly larger, effects (such as ELMs, divertor geometry, radiation, thermal gradient force, etc.) in determining the overall enrichment.
	fusion.gat.com /exp/1997/html-murakami/D2.2.html (486 words)

	AC 10/97: Boron-Doped Diamond Thin-Film Electrodes
		In boron-doped films, the boron impurity atoms substitute in place of some of the carbon atoms during film growth.
		At room temperature, some of the valence band electrons are thermally promoted to the boron acceptors, leaving free electrons in the dopant band and holes, or vacancies, in the valence band to support the flow of current.
		Consequently, the electrical conductivity of the film surface and the bulk is influenced by the boron-doping level, the grain boundaries, and the impurities.
	pubs.acs.org /hotartcl/ac/97/oct/boron.html (4109 words)

	Why are amethyst & smoky quartz colored? (color centers)
		In ruby the impurity is excited directly by the "visible" photon; in amethyst, it is not.
		Instead, the impurity in amethyst creates another unstable species in the crystal and this new species jumps to an excited state by absorbing a "visible" photon.
		An iron impurity is responsible for the violet color in amethyst by creatiing a color center.
	webexhibits.org /causesofcolor/12.html (1916 words)

	The Temple Institute: Understanding the Concept of Biblical Purity
		The most severe of all is that which is brought on by exposure to death; indeed, although there are many types of impurity, the state which Torah law is most commonly concerned with is generally associated with some aspect of death, either of a human being or another life form; or with sickness.
		Impurity indicates a spiritual imbalance, and the Temple is the place which restores this balance.
		For the impurity rendered by death is the contamination of a false vision, a lie.
	www.templeinstitute.org /red_heifer/biblical_purity.htm (1547 words)

	Smart Optical Memory (Site not responding. Last check: 2007-10-09)
		Impurity ions at the various substitution sites have slightly different crystal-field environments, which results in small spectral shifts that are distinguishable at cryogenic temperatures.
		Memory of the history of optical excitation is eventually lost through nuclear-spin relaxation, which may take as long as 24 hours, depending on the nature of the crystal host material and the storage temperature.
		When the crystal is illuminated by a complex time-sequence of laser pulses, each impurity ion sees the pulses as either in-phase (constructive interference, leading to more absorption) or out-of-phase (less absorption) with each other, depending on the ion's characteristic absorption frequency, the time separations, phase differences, and spectral composition of the laser pulses.
	www-mpl.sri.com /projects/pyu5310.html (1111 words)

	Impurity Transport in NCS (Site not responding. Last check: 2007-10-09)
		Measure impurity transport properties during various stages of the formation of the transport barrier in an NCS discharge.
		Assess the Z dependence of impurity transport in discharges in which ion thermal transport levels are near neoclassical.
		Assess whether a transport barrier forms and broadens in the particle channel in a similar manner as ion thermal channel during the prelude phase by varying the perturbation (i.e., gas puffing) time and measuring the helium transport properties in otherwise identical discharges.
	fusion.gat.com /exp/1997/html-murakami/T7.1.html (388 words)

	06.20.2001 - Quantum spin probe able to measure spin states at individual atoms; could have application in quantum ...
		The central spot is the nickle atom, surrounded by a cloverleaf pattern whose fourfold symmetry is indicative of the underlying d-wave nature of the high-temperature superconducting state.
		Qubits stored as closely packed impurity atoms in a solid crystal could be read out by an STM much like a recording head reads and writes magnetic bits on a CD.
		Davis's group discovered the power of their STM while studying the effect of single-atom impurities in pure samples of a copper oxide high-temperature superconductor (Bi2Sr2CaCu2O8+d) - dubbed BSCCO (BIS-ko) because it is composed of bismuth, strontium, calcium, copper and oxygen.
	www.berkeley.edu /news/media/releases/2001/06/20_physc.html (1284 words)

	Oxford Scholarship Online: Gentile Impurities and Jewish Identities
		Although purity and impurity were intimately connected with questions of identity and otherness in ancient Jewish culture, the terms "pure" and "impure" were employed in various ways by different groups of Jews to describe and inscribe sociocultural boundaries between Jews and Gentiles.
		This unexpected diversity of ancient Jewish views of Gentile impurity is tied to widely differing definitions of Jewish group identity and the access of Gentiles to that identity.
		These diverse views of the permeability of the Jewish-Gentile boundary through intermarriage or conversion, deriving in turn from diverse conceptions of Gentile impurity and Jewish identity, contributed to the rise of sectarianism in Second Temple Judaism, and to the separation of the early church from what would later become rabbinic Judaism.
	www.oxfordscholarship.com /oso/public/content/religion/0195151208/toc.html (458 words)

Try your search on: Qwika (all wikis)