Tungsten Trioxide Films

Tungsten trioxide films have been shown to have applications as the sensing element in gas sensors. One of the most important part of the gas sensor is gas sensitive element. The sensor's sensitivity, selectivity, to a large extent dependent, depends on the performance of gas sensitive element. The general gas sensor is thin film material. Study on tungsten trioxide films began 20 years ago, most is on the electrically induced discoloration, photochromic, electrochemistry and gas sensor performance. For hydrogen sensor, tungsten trioxide films have enormous potential. When tungsten trioxide contacts with hydrogen, the most change is the film colour from transparent to blue. At the same time, changes have taken place in film measured by optical instruments. So tungsten trioxide films are good hydrogen sensitive materials. After doping of rare metal, such as platinum and palladium, hydrogen sensitive properties of tungsten trioxide films can greatly improve. Tungsten trioxide films not only can be used for hydrogen sensor, after doping different elements in different conditions, can also be used for other gases sensitive materials, such as NH4, NO2, H2S, O3 and O2.

Tungsten trioxide films material is a kind of wide application of functional materials, has the very broad application prospects. This material can be used in electrically induced discoloration electrochromics, smart Windows, etc. In different field of application of the film materials have different requirements.
 
 
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Yellow Tungsten Oxide Physical Property

Tungsten outer electron configurations is sd46s, thus, five kinds of valence (+ 2, + 3, + 4, + 5 + 6) can present in the compounds. The valence of W in WO3 is highest in tungsten oxide. Usually the oxygen content of WO3 does not meet the strict stoichiometric ratio, it represented in the form of WO3-x.
 
WO3 formula is quite simple, but its physical properties is very complex.The melting point of WO3 reported in literature is 1473 ℃, but in 1100 ℃ WO3 starts sublimation, sublimation heat is 459.8 kJ/mol. Strictly meet the stoichiometric ratio of tungsten trioxide and without any impurities, WO3 should be transparent insulation. The forbidden band width is about 2.9 eV at room temperature.The WO3-x show n type semiconductor behavior, and forbidden band width is 2.4~2.8eV. Due to the phase change of the structure of WO3, with the change of temperature, resistivity of WO3 will appear jump phenomenon, its resistivity is commonly in 0.3~10 Ω·cm.
 
 
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Yellow Tungsten Oxide History

Yellow tungsten oxide is a kind of tungsten oxide.The production of yellow tungsten oxide should be traced to the discovery of tungsten. Tungsten has a rich history dating back to its discovery during the 18th century. Peter Woulfe was the first to recognize a new element in the naturally occurring mineral, wolframite. Tungsten was originally known as wolfram, explaining the choice of "W" for its elemental symbol. Swedish chemist Carl Wilhelm Scheele contributed to its discovery as well with his studies on the mineral scheelite.
 
In 1841, a chemist named Robert Oxland gave the first procedures for preparing tungsten trioxide and sodium tungstate. He was granted patents for his work soon after, and is considered to be the founder of systematic tungsten chemistry.
 
 
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Throwing Dart Tips

There are a number of basics to keep in-mind when you start throw dart. A steady Stance is very important. Don't lean way over the line to get closer to the board. This one is a tough habit for some people to beat, but to try, as leaning robs the darter of stability. The feet and legs should be positioned in a solid, comfortable, and relaxed stance, with weight distributed to both feet. Excessive leaning places nearly all of the body weight on one foot, tiring the shooter in long matches and damaging accuracy in the short run.

The few inches gained by leaning over the line are simply not worth the huge loss of balance and stability. Plus, leaning lowers the shoulder, forcing one to throw upwards, fighting gravity. Leaning also usually means tensing the major muscles of the body to preserve balance. This often results in a jerky release and poor follow-through, since the body is already off-balance.

A number of long-time players report back, knee, ankle, and foot pain, from spending many years standing on one foot while playing darts. Even in the short run, leaning to throw will cause minor pain in the small of the back. Especially for older players, a firm stance will stop this discomfort.

 

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Habits Sould Avoid

Keep your feet planted solidly on the floor, and avoid lunging, rocking, or lifting the back foot off the floor during the dart toss.Imagine that you are bowling, you still must follow-through! The same applies to Golf, Billiards, Basketball, and most every other sport. Follow-through after releasing the dart, ending up with your fingers fully extended, as though touching the spot that you want to hit.

Leaning, or rocking, is often done in an attempt to get a harder throw. The dartboard really does not care how hard you throw the dart. The only important thing is how accurately you throw it.!

Even a light throw, if accompanied by a smooth and extended follow-through, will easily reach the dart board and score.

Such wasted motion can really be a bad habit, as it affects the entire body and throw. Lifting the foot even partway from the floor deprives the body of good balance during the crucial moment of follow-through. The strength required to reach the board with any normal dart is minimal, and for best accuracy should be provided only by the fingers, wrist, and forearm. After the dart leaves your hand, let your hand and arm continue on towards the dartboard, ending with full extension, and the fingers pointing at the target.

Missing the board or hitting too low often cause beginners to think that more power is needed. This is rarely true, as one can tell by the fact that the missed darts usually hit hard enough to stick in the wall, which is quite a bit harder than a bristle dartboard. The problem lies with the accuracy of the throw and follow through. Even small children can be taught to throw accurately without lunging or using the shoulders in a throw.

If you feel short of power, stand upright, and keep your elbow up. The upper arm should be approximately parallel to the ground. This allows you to bring your arm back further, without hitting yourself in the face with the dart!

Stand Straight, Elbow Up, and you will effectively double the power of your throw without any extra effort. For one thing, the dart is much higher than when leaning, so gravity does much of the work for you.

 

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