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What is the relationship between crystalline boron and amorphous boron

The latest forecast from consulting firm AlixPartners is that the chip shortage may cost the global auto industry $110 billion; it will reduce global auto sodium aluminium silicate.

Because the melting and boiling points of crystal boron are also very high and the hardness is large, it is an atomic crystal;

What is boron? Is it good for people?

Chemical properties of boron

In a word, boron is mainly non-metallic in chemical properties, but some metallic in crystalline state. Therefore, it is often classified as a semi metallic or quasi metallic element. The chemical activity of boron is closely related to its purity, powder fineness and reaction conditions. The high-purity crystalline boron is quite stable, while the powder amorphous boron of general purity is relatively active; High purity boron is stable even if it is very fine, but it is quite active under the action of high temperature or strong oxidant.

What are the differences between high temperature superconductors and traditional superconductors?

Keywords: superconducting technology High temperature superconducting material MgB2 Yttrium barium copper oxide complex YBCO

1、 The Generation and Development of Superconducting Technology

Superconducting technology, as a new energy-saving technology and its environmental characteristics, will become the core technology in the 21st century. Its development has gone through three stages:

1. The first stage is the basic understanding and exploration of superconductivity and the advent of BCS theory.

In, Onnes found that the resistance of Hg dropped suddenly at 4. 00 to the extent that the instrument accuracy at that time could not be measured, that is, Hg would lose its resistance below a certain critical temperature Tc=4. Later, people also found this characteristic in Pb and other materials: when the critical conditions (critical temperature Tc, critical current Ic, critical magnetic field Hc) are met, the resistance of the material suddenly disappears, which is the zero resistance phenomenon of superconductivity. Another basic property of superconductors is complete diamagnetism. That is to say, when the superconductor is in the superconducting state, it can completely exclude the entry of magnetic field lines. [2] This phenomenon was discovered by Meissner and Oschenfeld in, so it is called the Meissner effect. These are the two basic properties of superconductors. In, B.T. Matthias research group of Bell Laboratories discovered alloy superconductive materials, which made the dawn of superconductivity in the 1960s, but it needed to show superconductivity at very low temperatures (in liquid helium).

2. The second stage is from to the discovery of high-temperature oxide U-Ba-Cu-0 in, which is the preparatory exploration stage for the application technology of superconductivity. Many countries have vigorously tried the application of superconductivity in laboratory scale; In, J. The mixed powder of silver and tin with excessive tin was filled into the silver tube and processed into wire rod. After heat treatment, Ic reached 1.5 at 4.2K and 8.8T ×/ cm2。 After that, Tc=23.3K for a long time is regarded as the limit value.

3. The third stage was the discovery of high-temperature copper oxide in, which opened the prelude to the development of superconductivity technology. The Lanthanum Silver Copper composite oxide discovered by Zurich scientists and others in has reached, which breaks through the traditional BCS theory and has caused great repercussions worldwide. [3] People began to look for higher critical temperature superconducting materials. Later in, Zhu Jingwu of the University of Houston and others found that the superconducting critical temperature (Tc=) of YBCO exceeded the liquid nitrogen temperature (b.p=), causing a world sensation; Because most superconductors used liquid helium as coolant before, the price of liquid helium is very high, which hinders the application of superconducting technology. Liquid nitrogen is cheap and easy to obtain (it is a by- sodium aluminium silicate, etc. If you are looking for high-quality materials, please feel free to contact us and send an inquiry.

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