As Donald left Wang Bin''s shop, Wang Bin cleaned up the shop and entered the system again.

    This time Wang Bin wants to buy a material technology in the system again, but this time he doesn''t want to buy materials and technologies that exceed his world level. After all, he has only 800 energy coins in his hand. He can''t buy very advanced technology at all. He can only buy materials and technologies that are similar to his world level.

    Of course, there are many good things in even the material technology with the same technical level as his world.

    After all, many materials have appeared in Wang Bin''s world, but even in Wang Bin''s world, these materials are technologies monopolized by foreign manufacturers and cannot be produced at home.

    For example, for the real high-performance bearing steel, domestic bearing manufacturers are basically imported from abroad. In addition, there are many materials that have a certain gap with foreign countries.

    However, this technology is sold in the system of the mall, and its price is not high, so Wang Bin is going to buy a material technology to increase the number of their products in Tiangong science and technology materials.

    Then, Wang Bin opened the purchase option of the technology owned by the system, and then the system listed the technologies he could buy, and asked the system to remove those outdated technologies.

    Soon, the selected technical catalogue of basic materials appeared in Wang Bin''s mind. At the same time, all kinds of materials with similar properties were concentrated together. For example, steel alone is divided into many types, such as carbon steel, structural steel, low-alloy steel, high-alloy steel, structural steel, tool steel, high-speed steel, spring steel, bearing steel, etc.

    Among these types of steel, there are many small types, which is only steel smelting technology. In the system catalog, there are many other metal and non-metallic materials in addition to steel.

    For example, copper alloy technology, aluminum alloy technology, lead alloy technology, silver alloy technology and so on in metal technology, while non-metallic material technology includes carbon fiber technology, silica gel synthesis technology, silicon wafer manufacturing technology, propylene manufacturing technology and so on.

    At the same time, the prices of these technologies are high and low. The low price is only dozens or hundreds of energy coins, but Wang Bin despises these technologies of dozens or hundreds of energy coins.

    Although these technologies are not backward technologies in the era of Wang Bin''s world, Wang Bin can be sure that technologies with such low prices will not be advanced. It is even possible that they have been widely used in Wang Bin''s world, and the products they produce are already cabbage prices.

    Wang Bin then asked the system to remove all the technologies below 500 energy coins.

    But after Wang Bin asked the system to remove all the technologies below 500 energy coins, he looked at the technology directory in his mind and suddenly lost more than half.

    So he focused his attention on his mind and looked at the technology catalog in his mind.

    Looking at the dazzling technology in his mind, Wang Bin really didn''t know how to choose for a moment. There were too many materials and technologies in it.

    When Wang Bin saw the semiconductor silicon wafer manufacturing technology, his heart was very excited. After all, this is a necessary material for electronic chips. Without semiconductor silica gel chips, he could not manufacture electronic chips at all. However, reason stopped his behavior.

    He knows that, in fact, the manufacturing of semiconductor silicon wafer is not a problem for Huaxia at present. The reason why Huaxia can''t manufacture high-end chips is that the problem is not on the silicon wafer, but on the lithography machine.

    However, according to the news some time ago, in the field of lithography, China has now reached the forefront of the world, and can produce a small amount of lithography machines of more than 10 nm.

    Therefore, it is certain that Huaxia will be able to solve the problem of chips in a short time. Therefore, Wang Bin no longer pays attention to the technology of semiconductor silicon chips. He browsed through the technology directory in his mind to see what materials and technologies are suitable for him.

    However, after looking for a long time, Wang Bin didn''t find any suitable materials and technologies. However, Wang Bin was not too anxious, but quit the system first. He wanted to know carefully what technology he chose to buy.

    After returning to reality, Wang Bin came to his laboratory, opened the computer in his laboratory that was not connected to the network, and inserted the U disk brought from Donald into the computer.

    Soon, Wang Bin had many videos, photos and text data on this USB flash drive.

    Then Wang Bin first looked at the text data carefully. He found that in the USB flash disk Donald gave him, it was about the performance of these glasses under the shooting of various weapons.

    In these data, the most powerful weapon is the test of pistol.

    According to the test data, as long as the glass thickness reaches 3mm and can resist the shooting of pistols with a caliber of less than 10mm in his era, and the thickness reaches 4mm, no pistol can break through this glass in his era.

    At the same time, as long as the thickness reached 4mm, most rifles in his era could not break through this glass.

    In addition, as Wang Bin expected before, as long as the thickness reaches 5mm, except for professional anti equipment blocking, all rifles and light machine guns can no longer break through this glass.

    Once the thickness reaches 6 mm, the defense ability of glass. It is to the extent that the heavy machine gun can not penetrate.

    At the same time, when the thickness of this glass reaches 10mm, artillery below 30mm has lost its effect on this glass, and can also resist mortar fire of about 40mm.

    If the thickness reaches 12mm, which is the limit of the glass thickness that Wang Bin and Tiangong technology can make, this glass can defend against the direct hit of 45mm caliber artillery.

    Just after reading these data, Wang Bin''s psychology secretly nodded his head. Although these data were stronger than Wang Bin had expected, they were not too unexpected.

    After all, Donald''s world is only equivalent to the scientific and technological level of Wang Bin''s World War II. In terms of the weapon level of that era, it is much worse than Wang Bin''s world. Therefore, it is very natural that the performance of these glasses is better than Wang Bin expected.

    The next data is the actual combat data of this glass installed on some land armored combat units. According to the data, when the armored vehicle is installed with this glass produced by Wang Bin and Tiangong technology, its combat efficiency is greatly improved, and the casualty ratio is greatly reduced.

    Before installing this glass, in order to ensure the safety of personnel in armored vehicles, generally speaking, the vision of vehicles is very narrow. If there is no corresponding need to follow, it is easy to be attacked by other soldiers, resulting in the loss of armored vehicles.

    However, the use of this glass is different. After using this glass, there is no need to use heavy steel for defense in the four weeks of armored vehicles. Like cars, wide glass windows can be installed around armor piercing vehicles. In this way, we can clearly see the situation in the four weeks, and it is naturally easier to find the sneak attack of enemy units.