tungsten

タングステン。W。wolfram 　 　

WordNet

1. a heavy grey-white metallic element; the pure form is used mainly in electrical applications; it is found in several ores including wolframite and scheelite (同)wolfram, W, atomic number 74
2. the 23rd letter of the Roman alphabet (同)w, double-u
3. a very hard heat-resistant steel containing tungsten (同)wolfram steel
4. a steel alloy made with chromium and tungsten

PrepTutorEJDIC

1. タングステン(金属元素;化学記号は W)
2. =tungsten
3. Watt / West; Western
4. wolfram(=tungsten)の原子記号

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/06/01 01:22:34」(JST)

wiki en

[Wiki en表示]

This article is about the chemical element. For other uses, see Tungsten (disambiguation).

Tungsten,  ₇₄W

General properties
Name, symbol	tungsten, W
Appearance	grayish white, lustrous
Pronunciation	/ˈtʌŋstən/; /ˈwʊlfrəm/ TUNG-stən; WUUL-frəm
Alternative name	wolfram
Tungsten in the periodic table
Mo ↑ W ↓ Sg tantalum ← tungsten → rhenium
Atomic number (Z)	74
Group, block	group 6, d-block
Period	period 6
Element category	transition metal
Standard atomic weight (±) (Ar)	183.84(1)
Electron configuration	[Xe] 4f14 5d4 6s2
per shell	2, 8, 18, 32, 12, 2
Physical properties
Phase	solid
Melting point	3695 K ​(3422 °C, ​6192 °F)
Boiling point	6203 K ​(5930 °C, ​10,706 °F)
Density near r.t.	19.25 g/cm3
when liquid, at m.p.	17.6 g/cm3
Critical point	13,892 K,  MPa
Heat of fusion	35.3 kJ/mol
Heat of vaporization	774 kJ/mol
Molar heat capacity	24.27 J/(mol·K)
vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 3477 3773 4137 4579 5127 5823
Atomic properties
Oxidation states	6, 5, 4, 3, 2, 1, 0, −1, −2, −4 ​(a mildly acidic oxide)
Electronegativity	Pauling scale: 2.36
Ionization energies	1st: 770 kJ/mol 2nd: 1700 kJ/mol
Atomic radius	empirical: 139 pm
Covalent radius	162±7 pm
Miscellanea
Crystal structure	​body-centered cubic (bcc)
Speed of sound thin rod	4620 m/s (at r.t.) (annealed)
Thermal expansion	4.5 µm/(m·K) (at 25 °C)
Thermal conductivity	173 W/(m·K)
Electrical resistivity	52.8 nΩ·m (at 20 °C)
Magnetic ordering	paramagnetic
Young's modulus	411 GPa
Shear modulus	161 GPa
Bulk modulus	310 GPa
Poisson ratio	0.28
Mohs hardness	7.5
Vickers hardness	3430–4600 MPa
Brinell hardness	2000–4000 MPa
CAS Number	7440-33-7
History
Naming	from German wolfram
Discovery	Carl Wilhelm Scheele (1781)
First isolation	Juan José Elhuyar and Fausto Elhuyar (1783)
Most stable isotopes of tungsten
iso NA half-life DM DE (MeV) DP 180W 0.12% 1.8×1018 y α 2.516 176Hf 181W syn 121.2 d ε 0.188 181Ta 182W 26.50% >1.7×1020 y (α) 1.772 178Hf 183W 14.31% >8×1019 y (α) 1.680 179Hf 184W 30.64% >1.8×1020 y (α) 1.123 180Hf 185W syn 75.1 d β− 0.433 185Re 186W 28.43% >4.1×1018 y (α) 1.656 182Hf (β−β−) – 186Os
Decay modes in parentheses are predicted, but have not yet been observed

Tungsten, also known as wolfram, is a chemical element with symbol W and atomic number 74. The word tungsten comes from the Swedish language tung sten, which directly translates to heavy stone. Its name in Swedish is volfram, however, in order to distinguish it from scheelite, which in Swedish is alternatively named tungsten.

A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth almost exclusively in chemical compounds. It was identified as a new element in 1781, and first isolated as a metal in 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the elements. Its high density is 19.3 times that of water, comparable to that of uranium and gold, and much higher (about 1.7 times) than that of lead. Polycrystalline tungsten is an intrinsically brittle and hard material, making it difficult to work. However, pure single-crystalline tungsten is more ductile, and can be cut with a hard-steel hacksaw.

Tungsten's many alloys have numerous applications, including incandescent light bulb filaments, X-ray tubes (as both the filament and target), electrodes in TIG welding, superalloys, and radiation shielding. Tungsten's hardness and high density give it military applications in penetrating projectiles. Tungsten compounds are also often used as industrial catalysts.

Tungsten is the only metal from the third transition series that is known to occur in biomolecules, where it is used in a few species of bacteria and archaea. It is the heaviest element known to be used by any living organism except uranium. Tungsten interferes with molybdenum and copper metabolism and is somewhat toxic to animal life.

Characteristics

Physical properties

In its raw form, tungsten is a hard steel-grey metal that is often brittle and hard to work. If made very pure, tungsten retains its hardness (which exceeds that of many steels), and becomes malleable enough that it can be worked easily. It is worked by forging, drawing, or extruding. Tungsten objects are also commonly formed by sintering.

Of all metals in pure form, tungsten has the highest melting point (3422 °C, 6192 °F), lowest vapor pressure (at temperatures above 1650 °C, 3000 °F) and the highest tensile strength. Although carbon remains solid at higher temperatures than tungsten, carbon sublimes, rather than melts, so tungsten is considered to have a higher melting point. Tungsten has the lowest coefficient of thermal expansion of any pure metal. The low thermal expansion and high melting point and tensile strength of tungsten originate from strong covalent bonds formed between tungsten atoms by the 5d electrons. Alloying small quantities of tungsten with steel greatly increases its toughness.

Tungsten exists in two major crystalline forms: α and β. The former has a body-centered cubic structure and is the more stable form. The structure of the β phase is called A15 cubic; it is metastable, but can coexist with the α phase at ambient conditions owing to non-equilibrium synthesis or stabilization by impurities. Contrary to the α phase which crystallizes in isometric grains, the β form exhibits a columnar habit. The α phase has one third of the electrical resistivity and a much lower superconducting transition temperature T_C relative to the β phase: ca. 0.015 K vs. 1–4 K; mixing the two phases allows obtaining intermediate T_C values. The T_C value can also be raised by alloying tungsten with another metal (e.g. 7.9 K for W-Tc). Such tungsten alloys are sometimes used in low-temperature superconducting circuits.

Isotopes

Main article: Isotopes of tungsten

Naturally occurring tungsten consists of five isotopes whose half-lives are so long that they can be considered stable. Theoretically, all five can decay into isotopes of element 72 (hafnium) by alpha emission, but only ¹⁸⁰W has been observed to do so with a half-life of (1.8 ± 0.2)×10¹⁸ years; on average, this yields about two alpha decays of ¹⁸⁰W in one gram of natural tungsten per year. The other naturally occurring isotopes have not been observed to decay, constraining their half-lives to be:

¹⁸²W, t_1/2 > 1.7×10²⁰ years

¹⁸³W, t_1/2 > 8×10¹⁹ years

¹⁸⁴W, t_1/2 > 1.8×10²⁰ years

¹⁸⁶W, t_1/2 > 4.1×10¹⁸ years

Another 30 artificial radioisotopes of tungsten have been characterized, the most stable of which are ¹⁸¹W with a half-life of 121.2 days, ¹⁸⁵W with a half-life of 75.1 days, ¹⁸⁸W with a half-life of 69.4 days, ¹⁷⁸W with a half-life of 21.6 days, and ¹⁸⁷W with a half-life of 23.72 h. All of the remaining radioactive isotopes have half-lives of less than 3 hours, and most of these have half-lives below 8 minutes. Tungsten also has 4 meta states, the most stable being ^179mW (t_1/2 6.4 minutes).

Chemical properties

Elemental tungsten resists attack by oxygen, acids, and alkalis.

The most common formal oxidation state of tungsten is +6, but it exhibits all oxidation states from −2 to +6. Tungsten typically combines with oxygen to form the yellow tungstic oxide, WO₃, which dissolves in aqueous alkaline solutions to form tungstate ions, WO2−
4.

Tungsten carbides (W₂C and WC) are produced by heating powdered tungsten with carbon. W₂C is resistant to chemical attack, although it reacts strongly with chlorine to form tungsten hexachloride (WCl₆).

In aqueous solution, tungstate gives the heteropoly acids and polyoxometalate anions under neutral and acidic conditions. As tungstate is progressively treated with acid, it first yields the soluble, metastable "paratungstate A" anion, W
7O6–
24, which over time converts to the less soluble "paratungstate B" anion, H
2W
12O10–
42. Further acidification produces the very soluble metatungstate anion, H
2W
12O6–
40, after which equilibrium is reached. The metatungstate ion exists as a symmetric cluster of twelve tungsten-oxygen octahedra known as the Keggin anion. Many other polyoxometalate anions exist as metastable species. The inclusion of a different atom such as phosphorus in place of the two central hydrogens in metatungstate produces a wide variety of heteropoly acids, such as phosphotungstic acid H₃PW₁₂O₄₀.

Tungsten trioxide can form intercalation compounds with alkali metals. These are known as bronzes; an example is sodium tungsten bronze.

History

In 1781, Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite (at the time named tungsten). Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid. In 1783, José and Fausto Elhuyar found an acid made from wolframite that was identical to tungstic acid. Later that year, at the Royal Basque Society in the town of Bergara, Spain, the brothers succeeded in isolating tungsten by reduction of this acid with charcoal, and they are credited with the discovery of the element.

In World War II, tungsten played a significant role in background political dealings. Portugal, as the main European source of the element, was put under pressure from both sides, because of its deposits of wolframite ore at Panasqueira. Tungsten's desirable properties such as resistance to high temperatures, its hardness and density, and its strengthening of alloys made it an important raw material for the arms industry, both as a constituent of weapons and equipment and employed in production itself, e.g., in tungsten carbide cutting tools for machining steel.

Etymology

The name "tungsten" (from the Swedish tung sten, "heavy stone") is used in English, French, and many other languages as the name of the element, but not in the Nordic countries. Tungsten was the old Swedish name for the mineral scheelite. The other name "wolfram" (or "volfram") is used in most European (especially Germanic and Slavic) languages, and is derived from the mineral wolframite, which is the origin of its chemical symbol, W. The name "wolframite" is derived from German "wolf rahm" ("wolf soot" or "wolf cream"), the name given to tungsten by Johan Gottschalk Wallerius in 1747. This, in turn, derives from "lupi spuma", the name Georg Agricola used for the element in 1546, which translates into English as "wolf's froth", and is a reference to the large amounts of tin consumed by the mineral during its extraction.

Occurrence

Wolframite, scale in cm

Tungsten is found in wolframite (iron–manganese tungstate (Fe,Mn)WO₄ being a solid solution of the minerals ferberite FeWO₄ and hübnerite MnWO₄) and scheelite (calcium tungstate (CaWO₄). Other tungsten minerals are moderately to very rare and have no economical value. They include the recently approved native tungsten.

Production

Tungsten mined in 2012

About 61,300 tonnes of tungsten concentrates were produced in the year 2009, and in 2010, world production of tungsten was about 68,000 tonnes. The main producers were as follows (data in tonnes):

Country	Production (2009)	Production (2010)	Production (2011)	Production (2012)
Australia	33	18	15	290
Austria	887	977	861	706
Bolivia	1,023	1,204	1,124	1,247
Brazil	192	166	244	381
Burma	874	163	140	140
Burundi	110	100	165	190
Canada	1,964	420	1,966	2,194
China	51,000	59,000	61,800	64,000
Congo	200	25	70	95
North Korea	100	110	110	100
Mongolia	39	20	13	66
Peru	502	571	439	276
Portugal	823	799	819	763
Russia	2,665	2,785	3,314	3,537
Rwanda	380	330	520	700
Spain	225	240	497	542
Thailand	190	300	160	80
Uganda	7	44	8	21
Vietnam	725	1,150	1,635	1,050
Total	61,200	68,400	73,900	76,400

There is additional production in the U.S., but the amount is proprietary company information. U.S. reserves are 140,000 tonnes.

Tungsten is considered to be a conflict mineral due to the unethical mining practices observed in the Democratic Republic of the Congo.

There is a large deposit of tungsten ore on the edge of Dartmoor in the United Kingdom, which was exploited during World War I and World War II as the Hemerdon Mine. With recent increases in tungsten prices, as of 2014 this mine has been reactivated.

Tungsten is extracted from its ores in several stages. The ore is eventually converted to tungsten(VI) oxide (WO₃), which is heated with hydrogen or carbon to produce powdered tungsten. Because of tungsten's high melting point, it is not commercially feasible to cast tungsten ingots. Instead, powdered tungsten is mixed with small amounts of powdered nickel or other metals, and sintered. During the sintering process, the nickel diffuses into the tungsten, producing an alloy.

Tungsten can also be extracted by hydrogen reduction of WF₆:

WF₆ + 3 H₂ → W + 6 HF

or pyrolytic decomposition:

WF₆ → W + 3 F₂ (ΔH_r = +)

Tungsten is not traded as a futures contract and cannot be tracked on exchanges like the London Metal Exchange. The prices are usually quoted for tungsten concentrate or WO₃. If converted to the metal equivalent, they were about US$19 per kilogram in 2009.

Applications

Close-up of a tungsten filament inside a halogen lamp

Tungsten carbide ring (jewelry)

1 kilogram tungsten cylinder (scale shown below)

Approximately half of the tungsten is consumed for the production of hard materials – namely tungsten carbide – with the remaining major use being in alloys and steels. Less than 10% is used in other chemical compounds.

Hard materials

Tungsten is mainly used in the production of hard materials based on tungsten carbide, one of the hardest carbides, with a melting point of 2770 °C. WC is an efficient electrical conductor, but W₂C is less so. WC is used to make wear-resistant abrasives, and "carbide" cutting tools such as knives, drills, circular saws, milling and turning tools used by the metalworking, woodworking, mining, petroleum and construction industries. Carbide tooling is actually a ceramic/metal composite, where metallic cobalt acts as a binding (matrix) material to hold the WC particles in place. This type of industrial use accounts for about 60% of current tungsten consumption.

The jewelry industry makes rings of sintered tungsten carbide, tungsten carbide/metal composites, and also metallic tungsten. WC/metal composite rings use nickel as the metal matrix in place of cobalt because it takes a higher luster when polished. Sometimes manufacturers or retailers refer to tungsten carbide as a metal, but it is a ceramic. Because of tungsten carbide's hardness, rings made of this material are extremely abrasion resistant, and will hold a burnished finish longer than rings made of metallic tungsten. Tungsten carbide rings are brittle, however, and may crack under a sharp blow.

Alloys

Further information: Tantalum-tungsten alloys

The hardness and density of tungsten are applied in obtaining heavy metal alloys. A good example is high speed steel, which can contain as much as 18% tungsten. Tungsten's high melting point makes tungsten a good material for applications like rocket nozzles, for example in the UGM-27 Polaris submarine-launched ballistic missile. Tungsten alloys are used in a wide range of different applications, including the aerospace and automotive industries and radiation shielding. Superalloys containing tungsten, such as Hastelloy and Stellite, are used in turbine blades and wear-resistant parts and coatings.

Armaments

Tungsten, usually alloyed with nickel and iron or cobalt to form heavy alloys, is used in kinetic energy penetrators as an alternative to depleted uranium, in applications where uranium's radioactivity is problematic even in depleted form, or where uranium's additional pyrophoric properties are not required (for example, in ordinary small arms bullets designed to penetrate body armor). Similarly, tungsten alloys have also been used in cannon shells, grenades and missiles, to create supersonic shrapnel. Tungsten has also been used in Dense Inert Metal Explosives, which use it as dense powder to reduce collateral damage while increasing the lethality of explosives within a small radius.

Chemical applications

Tungsten(IV) sulfide is a high temperature lubricant and is a component of catalysts for hydrodesulfurization. MoS₂ is more commonly used for such applications.

Tungsten oxides are used in ceramic glazes and calcium/magnesium tungstates are used widely in fluorescent lighting. Crystal tungstates are used as scintillation detectors in nuclear physics and nuclear medicine. Other salts that contain tungsten are used in the chemical and tanning industries.

Tungsten trioxide powder

Tungsten oxide (WO₃) is incorporated into selective catalytic reduction (SCR) catalysts found in coal-fired power plants. These catalysts convert nitrogen oxides (NO_x) to nitrogen (N₂) and water (H₂O) using ammonia (NH₃). The tungsten oxide helps with the physical strength of the catalyst and extends catalyst life.

Niche uses

Applications requiring its high density include weights, counterweights, ballast keels for yachts, tail ballast for commercial aircraft, and as ballast in race cars for NASCAR and Formula One; depleted uranium is also used for these purposes, due to similarly high density. 75-kg blocks of tungsten were used as "cruise balance mass devices" on the entry vehicle portion of the 2012 Mars Science Laboratory spacecraft. It is an ideal material to use as a dolly for riveting, where the mass necessary for good results can be achieved in a compact bar. High-density alloys of tungsten with nickel, copper or iron are used in high-quality darts (to allow for a smaller diameter and thus tighter groupings) or for fishing lures (tungsten beads allow the fly to sink rapidly). Some cello C strings are wound with tungsten. The extra density gives this sting more projection and often cellists will buy just this string and use it with 3 strings from a different set.

Sodium tungstate is used in Folin-Ciocalteu's reagent, a mixture of different chemicals used in the "Lowry Assay" for protein content analysis.

Gold substitution

Its density, similar to that of gold, allows tungsten to be used in jewelry as an alternative to gold or platinum. Metallic tungsten is hypoallergenic, and is harder than gold alloys (though not as hard as tungsten carbide), making it useful for rings that will resist scratching, especially in designs with a brushed finish.

Because the density is so similar to that of gold (tungsten is only 0.36% less dense), tungsten can also be used in counterfeiting of gold bars, such as by plating a tungsten bar with gold, which has been observed since the 1980s, or taking an existing gold bar, drilling holes, and replacing the removed gold with tungsten rods. The densities are not exactly the same, and other properties of gold and tungsten differ, but gold-plated tungsten will pass superficial tests.

Gold-plated tungsten is available commercially from China (the main source of tungsten), both in jewelry and as bars.

Electronics

Because it retains its strength at high temperatures and has a high melting point, elemental tungsten is used in many high-temperature applications, such as light bulb, cathode-ray tube, and vacuum tube filaments, heating elements, and rocket engine nozzles. Its high melting point also makes tungsten suitable for aerospace and high-temperature uses such as electrical, heating, and welding applications, notably in the gas tungsten arc welding process (also called tungsten inert gas (TIG) welding).

Tungsten electrode used in a Gas tungsten arc welding torch

Because of its conductive properties and relative chemical inertness, tungsten is also used in electrodes, and in the emitter tips in electron-beam instruments that use field emission guns, such as electron microscopes. In electronics, tungsten is used as an interconnect material in integrated circuits, between the silicon dioxide dielectric material and the transistors. It is used in metallic films, which replace the wiring used in conventional electronics with a coat of tungsten (or molybdenum) on silicon.

The electronic structure of tungsten makes it one of the main sources for X-ray targets, and also for shielding from high-energy radiations (such as in the radiopharmaceutical industry for shielding radioactive samples of FDG). It is also used in gamma imaging as a material from which coded apertures are made, due to its excellent shielding properties. Tungsten powder is used as a filler material in plastic composites, which are used as a nontoxic substitute for lead in bullets, shot, and radiation shields. Since this element's thermal expansion is similar to borosilicate glass, it is used for making glass-to-metal seals.

Biological role

Tungsten, at atomic number 74, is the heaviest element known to be biologically functional, with the next heaviest being iodine (Z = 53). It is used by some bacteria, but not in eukaryotes. For example, enzymes called oxidoreductases use tungsten similarly to molybdenum by using it in a tungsten-pterin complex with molybdopterin (molybdopterin, despite its name, does not contain molybdenum, but may complex with either molybdenum or tungsten in use by living organisms). Tungsten-using enzymes typically reduce carboxylic acids to aldehydes. The tungsten oxidoreductases may also catalyse oxidations. The first tungsten-requiring enzyme to be discovered also requires selenium, and in this case the tungsten-selenium pair may function analogously to the molybdenum-sulfur pairing of some molybdenum cofactor-requiring enzymes. One of the enzymes in the oxidoreductase family which sometimes employ tungsten (bacterial formate dehydrogenase H) is known to use a selenium-molybdenum version of molybdopterin. Acetylene hydratase is an unusual metalloenzyme in that it catalyzes a hydration reaction. Two reaction mechanisms have been proposed, in one of which there is a direct interaction between the tungsten atom and the C≡C triple bond. Although a tungsten-containing xanthine dehydrogenase from bacteria has been found to contain tungsten-molydopterin and also non-protein bound selenium, a tungsten-selenium molybdopterin complex has not been definitively described.

In soil, tungsten metal oxidizes to the tungstate anion. It can be selectively or non-selectively imported by some prokaryotic organisms and may substitute for molybdate in certain enzymes. Its effect on the action of these enzymes is in some cases inhibitory and in others positive. The soil's chemistry determines how the tungsten polymerizes; alkaline soils cause monomeric tungstates; acidic soils cause polymeric tungstates.

Sodium tungstate and lead have been studied for their effect on earthworms. Lead was found to be lethal at low levels and sodium tungstate was much less toxic, but the tungstate completely inhibited their reproductive ability.

Tungsten has been studied as a biological copper metabolic antagonist, in a role similar to the action of molybdenum. It has been found that tetrathiotungstates may be used as biological copper chelation chemicals, similar to the tetrathiomolybdates.

Precautions

Because tungsten is rare and its compounds are generally inert, the effects of tungsten on the environment are limited. The median lethal dose LD₅₀ depends strongly on the animal and the method of administration and varies between 59 mg/kg (intravenous, rabbits) and 5000 mg/kg (tungsten metal powder, intraperitoneal, rats).

People can be exposed to tungsten in the workplace by breathing it in, swallowing it, skin contact, and eye contact. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 5 mg/m³ over an 8-hour workday and a short term limit of 10 mg/m³.

Patent claim

Tungsten is unique amongst the elements in that it has been the subject of patent proceedings. In 1928, a US court rejected General Electric's attempt to patent it, overturning U.S. Patent 1,082,933 granted in 1913 to William D. Coolidge.

See also

• Field emission gun
• Tungsten oxide
• List of chemical elements name etymologies
• List of chemical elements naming controversies

References

External links

• Properties, Photos, History, MSDS
• CDC – NIOSH Pocket Guide to Chemical Hazards
• Tungsten at The Periodic Table of Videos (University of Nottingham)
• Picture in the collection from Heinrich Pniok
• Elementymology & Elements Multidict by Peter van der Krogt – Tungsten
• International Tungsten Industry Association

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 指輪などが抜けなくなった場合の対処法 ring entrapment and removal
• 2. 頭頸部癌に対する放射線療法の一般原則 general principles of radiation therapy for head and neck cancer
• 3. 職業性肺疾患のイメージング imaging of occupational lung diseases
• 4. 画像診断検査やIVRによる医療従事者の職業被曝リスク radiation risk to healthcare workers from diagnostic and interventional imaging procedures
• 5. 消化管出血のマネージメントにおけるアルゴンプラズマ凝固法 argon plasma coagulation in the management of gastrointestinal hemorrhage

English Journal

• The textural properties and microstructure of konjac glucomannan - tungsten gels induced by DC electric fields.

• Wang L1, Zhuang Y2, Li J3, Pang J4, Liu X5.
• Food chemistry.Food Chem.2016 Dec 1;212:256-63. doi: 10.1016/j.foodchem.2016.05.162. Epub 2016 May 28.
• Konjac glucomannan - tungsten (KGM-T) gels were successfully prepared under DC electric fields, in the presence of sodium tungstate. The textural properties and microstructure of the gels were investigated by Texture Analyzer, Rheometer and SEM. Based on the response surface methodology (RSM) result
• PMID 27374531

• Detection of nitrogen dioxide down to ppb levels using flower-like tungsten oxide nanostructures under different annealing temperatures.

• Wang C1, Ding M1, Kou X1, Guo L1, Feng C1, Li X1, Zhang H1, Sun P1, Sun Y2, Lu G3.
• Journal of colloid and interface science.J Colloid Interface Sci.2016 Dec 1;483:314-20. doi: 10.1016/j.jcis.2016.08.050. Epub 2016 Aug 22.
• 3D hierarchical flower-like WO3·0.33H2O nanostructures were synthesized via a facile solvothermal method without using any template or surfactant. After annealed at high temperature, the as-prepared WO3·0.33H2O would partly or fully transform into monoclinic WO3 with the morphology almost unchange
• PMID 27565963

• Reliable Diameter Control of Carbon Nanotube Nanobundles Using Withdrawal Velocity.

• Shin JH1, Kim K1, An T2, Choi W3, Lim G4.
• Nanoscale research letters.Nanoscale Res Lett.2016 Dec;11(1):385. doi: 10.1186/s11671-016-1600-9. Epub 2016 Sep 1.
• Carbon nanotube (CNT) nanobundles are widely used in nanoscale imaging, fabrication, and electrochemical and biological sensing. The diameter of CNT nanobundles should be controlled precisely, because it is an important factor in determining electrode performance. Here, we fabricated CNT nanobundles
• PMID 27581602

• Special Grain Boundaries in Ultrafine-Grained Tungsten.

• Dudka OV1, Ksenofontov VA2, Sadanov EV2, Starchenko IV2, Mazilova TI2, Mikhailovskij IM2.
• Nanoscale research letters.Nanoscale Res Lett.2016 Dec;11(1):332. doi: 10.1186/s11671-016-1488-4. Epub 2016 Jul 15.
• Field ion microscopy and computer simulation were used for the study of an atomic structure high-angle grain boundary in hard-drawn ultrafine-grained tungsten wire. These boundaries with special misorientations are beyond the scope of the coincident site lattice model. It was demonstrated that the s
• PMID 27416905

Japanese Journal

• Superconductivity in Tungsten-Carbide Nanowires Deposited from the Mixtures of W(CO)

• Dai Jun,Onomitsu Koji,Kometani Reo,Krockenberger Yoshiharu,Yamaguchi Hiroshi,Ishihara Sunao,Warisawa Shin'ichi
• Jpn J Appl Phys 52(7), 075001-075001-5, 2013-07-25
• … Tungsten-carbide (W-C) nanowires have been deposited by focused-ion-beam chemical vapor deposition (FIB-CVD). …
• NAID 150000107339

• X-ray Photon Counting Using 100 MHz Ready-Made Silicon P--Intrinsic--N X-ray Diode and Its Application to Energy-Dispersive Computed Tomography

• Kodama Hajime,Watanabe Manabu,Sato Eiichi,Oda Yasuyuki,Hagiwara Osahiko,Matsukiyo Hiroshi,Osawa Akihiro,Enomoto Toshiyuki,Kusachi Shinya,Sato Shigehiro,Ogawa Akira
• Jpn J Appl Phys 52(7), 072202-072202-6, 2013-07-25
• … At a tube voltage of 90 kV, we observe K-series characteristic X-rays of tungsten. …
• NAID 150000107331

• Ultrafast ellipsometric interferometry for direct detection of coherent phonon strain pulse profiles

• Matsuda Osamu,Tomoda Motonobu,Tachizaki Takehiro,Koiwa Shun,Ono Atsushi,Aoki Kae,Beardsley Ryan P.,Wright Oliver B.
• Journal of the Optical Society of America B - Optical Physics 30(7), 1911-1921, 2013-07-00
• … We demonstrate for a tungsten film the quantitative extraction of the strain pulse shape free of distortions arising from the photoelastic effect, and analyze the results with the two-temperature model to obtain the value g approximate to 3 x 10(17) Wm(-3) K-1 for the electron-phonon coupling constant. …
• NAID 120005316996

• 5.ヘリカル炉の構造とダイバータ設計(<小特集>ヘリカル型核融合炉設計の現状と展望)

• 田村 仁,増崎 貴,後藤 拓也,時谷 政行,芦川 直子
• プラズマ・核融合学会誌 89(6), 393-398, 2013-06-25
• ヘリカル炉を構成する機器について,必要なスペースの確保と保守性を考慮し,全体の整合性の取れた3次元構造設計を進めた.ダイバータについては,機器設計に周辺磁力線構造を考慮し,必要な熱・構造設計,配置と粒子・熱負荷の排気・除去方法の検討を行った.また,ダイバータ候補材料について,使用照射環境を考慮した熱的・機械的評価を行った.遠隔保守に関しては,保守環境の検討とヘリカル炉に適用する保守の種類について調 …
• NAID 110009612754

Related Links

• Tungsten

Tungstenは、複数階層のグループ化とウィンドウ分割ができるシンプルなWebブラウザです。ブラウザだけでなくあらゆるウィンドウのタブ化も可能。Windows専用。Tungstenは、複数階層のグループ化、ウィンドウ分割ができるシンプルなWeb ...

• Tungsten (W) - Chemical & Physical Properties

Chemical & Physical Properties of Tungsten (W) Element | MTS provides additional information on: Atomic Number, Atomic Weight, Melting Point & Group Number ... Background Information The word tungsten means “heavy stone ...

• Tungsten--オールフリーソフト Windows 7・8・10対応のフリーソフト--

Tungstenの紹介。対応OS Vista(64bit)/7(64bit)/8(64bit)/8.1(64bit)/10(64bit)、言語-日本語、ダウンロード先のリンク。説明 TungstenはBlinkとTridentのダブルエンジンを搭載して、ウインドウ分割もできるタブブラウザです。

Related Pictures

---

★リンクテーブル★

リンク元	「W」「タングステン」
拡張検索	「tungsten compound」

「W」

　　[★]

• トリプトファン tryptophan Trp
• ライジング数 writhing number
• ワット watt
• タングステン tungsten

　 　 　

「タングステン」

　　[★]

英

tungsten、W

関

ウォルフラム

「tungsten compound」

　　[★]

• タングステン化合物