Tungsten hexafluoride (WF₆), colorless gas or light yellow liquid, solid is easy to deliquescent white crystals, smoke in humid air. Tungsten hexafluoride is a kind of tungsten fluoride which is used in the chemical evaporation of tungsten and as a fluoride agent. It can be reduced to tungsten and HF by hydrogen and other reducing gases at high temperature.

We all know that from a rational point of view, tungsten carbide ring can be used as decorations; from a perceptual point of view, tungsten carbide ring is not just decorations, because it can add a bit of personality and fashion sense to the trend. Not only that, the specially designed tungsten carbide ring can also be used for self-defense. Moreover, this hard, diamond-like ring can also be used to break the window and escape. In the end, the "black technology" application of this tungsten carbide ring will be revealed.

Recently, researchers at the University of Science and Technology of Taiwan successfully fabricated a nanofiber membrane, a purple tungsten oxide/polylactic acid fiber membrane (WWO2.72/PLA), through a novel nanometer to submicron ultrafine fiber processing method.

We all know that solar energy is a clean energy source, and it is inexhaustible. According to statistics, the energy consumption in the world for one year is only equivalent to the solar energy that hits the earth on a day. In other words, sunlight provides us with enough renewable energy. Not only that, but the potential of sunlight is converted into heat. Therefore, solar energy is widely used for residential heating, seawater desalination, sewage treatment, and steam generation. However, materials that are inexpensive and have high photothermal conversion efficiency need to be explored. In other words, the development and preparation of photothermal materials still faces many challenges.

All in all, the development of efficient photothermal materials is a very important issue. Only by solving this problem can we obtain a photothermal material with higher solar-thermal conversion efficiency and more efficient water evaporation performance.

Therefore, recently, the Taiwan University of Science and Technology has sent good news. Their researchers have successfully prepared a nanofiber membrane - mainly obtained by melt electrospinning to reduce tungsten oxide / polylactic acid. Among them, the tungsten oxide used is purple tungsten oxide, a metal oxide having a strong near-infrared (NIR) light absorbing ability. Therefore, there is no doubt that the NIR photothermal conversion performance of the obtained nanofiber membrane is improved.

Based on this, the researchers incorporated the nano-violet tungsten oxide particles into a polylactic acid matrix by melt processing, and then extruded the composite into a wire using a single screw extruder. Thereafter, a fiber membrane was prepared from the extrusion line of the purple tungsten oxide/polylactic acid composite by melt electrospinning. It must be said that the cost of preparing nanofiber membranes by the technique of melt electrospinning is low and effective. In addition, this process does not add chemicals to the harmful environment, which is conducive to environmental protection.

Then, the researchers applied the resulting fiber membranes to practice. They applied a molten electrospun purple tungsten oxide/polylactic acid fiber membrane design with surface hydrophobicity and floating on water to the steam generation based on the solar heating interface concept. The results of the practice show that the water evaporation efficiency of the photothermal fiber membrane containing the purple tungsten oxide nanoparticles (7 wt%) is about 81% higher than that of the pure polylactic acid fiber membrane (PLA fiber membrane). The results of this study provide the idea for the development of a new type of photothermal fiber membrane, that is, the development of a new type of photothermal fiber membrane that enhances the performance of light-driven water evaporation, making it effective for water treatment and desalination.

We must first understand what is electrospinning? Moreover, there are many techniques for preparing ultrafine fibers at present. Among them, electrospinning (electrospinning) is a new processing method capable of continuously and rapidly preparing nanometer to submicron ultrafine fibers. In recent years, people have been very concerned about it. Because, in theory, any polymer material that can be melted or dissolved can be electrospun, not just PLA, but also other such as nylon, polyurethane, polyoxyethylene, polyacrylonitrile, polyaluminum. Polymers such as amines, polyvinyl alcohols, and polycaprolactones are also acceptable. Of course, the reason why electrospinning has been highly valued in recent years is thanks to the development of nanotechnology.

Melt electrospinning is a method of electrospinning. Another electrospinning method is solution electrospinning. At present, the solution electrospinning technology is very mature, but there are problems such as low production efficiency, solvent recovery, and emission pollution. In contrast, melt electrospinning is considered to be a more economical, environmentally friendly, and safer electrospinning technique because it does not require the addition of any solvents, is environmentally friendly, and produces a smooth fiber surface. No flaws, and high production efficiency. Because of the characteristics of the process itself, the melt electrospinning technology has been applied in the fields of filtration protection, biomedicine and energy storage packaging.

We should be grateful to the hard work of a generation of photothermal materials researchers, who let light and thermal materials and nanotechnology not only be materials and technology, but a combination of the two and even more.

According to the news released by the Ministry of National Defense of the People's Republic of China, the Russian "Oriental-2018" strategic exercise that was invited to participate in this military is the largest strategic exercise organized by the Russian military in recent years. This time is also the largest outbound performance in the history of our military. Our army has a military force of about 3,200 troops, and has invested more than 1,000 vehicles including 99 tanks, 30 fixed-wing aircraft and helicopters.

The content of this exercise has been expanded from the previous "joint anti-terrorism" to traditional security issues such as "organizing joint defense and counterattack". Compared with the previous "Peace Mission" exercise, this time the strategic exercise level is higher, the scale is larger, the elements are more complete, and the unity is higher - marking the level of political strategic mutual trust and military cooperation between China and Russia reaching a record high.

The Sino-Russian joint military exercise was staged at the Russian training ground in Chugor. At the time of the golden autumn, the Chugor grassland presents a scene of high altitude. "The ground iron armor broke into the air" and "the air warplane roared". This scene was carried out almost simultaneously, adding a lot of "fireworks" to Chugor.

In this exercise, a series of heavyweight "star" equipment of our army were all stunningly displayed. Among them, the domestic 99 improved main battle tank was the most eye-catching. So, let's take a look at the things of our Army's 99-type main battle tank.

We learned from the Internet that the comprehensive performance of the 99-type main battle tank reached the mainstream level of the international third-generation main battle tank. The debut of the 99 tanks was on the National Day parade in the 50th anniversary of the founding of the People's Republic of China in 1991. It also participated in the military parade of the 60th anniversary of the founding of the People's Republic of China. It has also appeared in the Sino-Russian joint military exercise many times.

The Type 99 main battle tank is equipped with the latest domestic 125mm smoothbore gun, automatic loader, advanced command fire control system and high-powered engine. It can launch three different types of shells - tungsten alloy tail stabilizer shelling armor-piercing projectile , armor-piercing ammunition and grenades. It emits the third generation of long-diameter tungsten alloy tail stabilizers, and the initial speed is up to 1,780 meters per second. Moreover, it can penetrate 850 mm thick at a distance of two kilometers. Homogeneous armor.

It is reported that the Type 99 main battle tank is equivalent in firepower to the M1A2 and Leopard 2A6. Our Army's Type 99 tanks are available in basic, first-stage, second-stage, and third-stage (99A) models. One of the main ways to distinguish the Type 99 tank model is to look at the turret. He said: "The 99 main battle tanks use welded turrets. Since then, improvements have been made to improve the turrets to improve tank protection, so we can distinguish the different types of tanks according to turret changes."

He also said: "The basic turret of the 99 main battle tank is best identified. It is a square turret. From the front, it is more similar to the M1 main battle tank. The first phase of the 99 main battle tank is a tapered wedge turret. Compared with the basic type, the biggest change is to add additional armor in the tank turret and the car body. The 99 main battle tank is improved in the second phase, and compared with the first-stage improvement type, the parallel machine gun leaves less blank space. 99A, Still a mystery."

This time, the main battle tank that our army participated in was not the 99A modified tank that many people thought, but it should be the 99 second-stage improved main battle tank. Of course, the 99-stage modified tank also showed the overall performance of the T-72B3 main battle tank superior to the Russian military in the exercise, although it is not the latest main battle tank of our army.

For example, the Russian T-72B3 tank captain is not equipped with a night vision system, only the gunner is equipped, so the captain needs to obtain images from the gunner night vision system. From this point of view, the battlefield situational awareness of the 99th phase of the improved tank is better than that of the T-72B3 tank. It is equipped with a vehicle-length day and night observation mirror, so that the captain can independently observe the battlefield situation and instruct the gunner to strike the target without much trouble.

Finally, let's take a look at the German "Focus" weekly website titled "The World's Strongest Tanks" ranking, ranking 10th to the first place for Ukraine's "Opirot", Russia's T-90 main battle tank Israel's "Meikava 4" main battle tank, France's Leclerc main battle tank, Japan's 10 main battle tank, South Korea's K-2 Panther main battle tank, Russia's T-14 Amata main battle Tanks, China's 99-type main battle tank, Germany's Leopard 2A7 main battle tank and the US M1A2 "Abrams".