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尖晶石型陶瓷材料的结构，性质及应用探究摘要：分析了尖晶石的晶体结构，几种不同的类型以及其的性质，重点就尖晶石型陶瓷材料的介电、磁性能以及半导性质进行了阐述，并对其应用做了简单表述。
关键词：尖晶石型结构特征性质与应用1.序言从广义上讲，尖晶石是指所有属于尖晶石族的矿物，它们多是由熔融的岩浆侵入到不纯的灰岩或白云岩中，经过接触变质作用而形成，化学通式是AO·B2O3或AB2O4，其中，A 代表二价金属离子，例如镁、铁、镍、锌，B代表三价金属离子[1]，例如铝、铁、铬、锰。
人们通常以B位离子来命名，如铝尖晶石、铁尖晶石、铬尖晶石。
而习惯于把铝镁尖晶石称为尖晶石。
2.尖晶石的晶体结构特征尖晶石的晶体结构属于七大晶系中的等轴晶系，六八面体晶类Oh-m3m(3L44L36L29PC)。
常呈八面体晶形，有时与菱形十二面体和立方体成聚形。
常依(111)为双晶面和接合面构成尖晶石律双晶。
基本结构是四面体与八面体层相间，四面体与八面体数之比为1:2。
氧原子为立方紧密堆积，即氧按ABC的顺序在垂直于(111)晶面的方向紧密堆积。
三价金属阳离子占据六次配位的八面体空隙，二价金属阳离子占据四次配位的四面体空隙。
这种结构称为正常尖晶石型结构。
若二价金属阳离子和半数三价金属阳离子占据八面体空隙，另半数三价金属阳离子占据四面体空隙，则构成反尖晶石型结构[1]。
如TiMg2O4，TiZn2O4，TiMn2O4。
除此之外还有混合型中间状态的存在。
最后使每个晶胞中的8/64的四面体间隙和16/32的八面体间隙被填充。
根据经验数据可将大部分二、三价离子的优先顺序排出：Zn2+，Cd2+，Ga2+，In3+，Mn2+，Fe3+，Mn3+，Fe2+，Mg2+，Cu2+，Co2+，Ti3+，Ni2+，Cr3+，越往前倾向于四面体填隙，反之则倾向于八面体填隙[2]。
尖晶石族矿物有很多种固溶体，这是因为尖晶石中类质同象替代现象很普遍，在晶体结构不改变或晶格没有任何变形的情况下，其中的组分可以被这组矿物中的其他组分大量的代替。
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2016年第35卷第8期·2580·化 工 进 展氨-碳酸盐法分离PTA 废渣中的钴和锰何沁华1，刘维桥1，邹超1，魏成文1，尚通明1，周全法1，高峰2（1江苏理工学院，江苏 常州 213000；2无锡中经金属粉末有限公司，江苏 无锡 214000）摘要：精对苯二甲酸（PTA ）生产中的废钴锰催化剂中钴低锰高，常用的钴锰分离方法一般不适用，分离钴锰时非常容易互相夹带，导致分离不完全。
本文采用氨-碳酸盐法分离PTA 废渣浸出液中的钴和锰。
在正交试验的基础上，以钴剩余率和锰沉淀率作为考核指标，考察了碳酸盐的种类、反应时间、反应温度、搅拌速度、氨的用量和碳酸盐的用量等因素对钴、锰分离效果的影响。
实验结果表明，在氨-碳酸钠、氨-碳酸铵、氨-碳酸氢铵3种溶液中，最佳搅拌速度、反应时间、反应温度分别为200r/min 、8h 和20℃，氨的最佳用量分别为理论化学反应计量的1.9倍、1.4倍和1.7倍，碳酸盐的用量分别为理论化学反应计量的1.0倍、1.3倍和1.3倍。
在最佳反应条件下，氨-碳酸钠、氨-碳酸铵、氨-碳酸氢铵3种溶液中，钴的最大剩余率分别可达到96.0%、99.8%和99.5%，锰沉淀率均可达到100%。
关键词：废物处理；回收；配合物；分离中图分类号：X 789；TQ 09 文献标志码：A 文章编号：1000–6613（2016）08–2580–06 DOI ：10.16085/j.issn.1000-6613.2016.08.44Study on separation of cobalt and manganese from waste residue of PTAby ammonia-carbonate leachingHE Qinhua 1，LIU Weiqiao 1，ZOU Chao 1，WEI Chengwen 1，SHANG Tongming 1，ZHOU Quanfa 1，GAO Feng 2（1Jiangsu University of Technology ，Changzhou 213000，Jiangsu ，China ；2Wuxi Zhongjing （Metal ）Powder Co.，Ltd.，Wuxi 214000，Jiangsu ，China ）Abstract ：The content of cobalt in the waste cobalt and manganese catalyst in the production of PTA was low and the content of manganese was high. The common cobalt and manganese separation methods generally were not suitable for this material and would make cobalt and manganese mixed with each other ，leading to incomplete separation. Ammonia - carbonate method was used in the separation of the cobalt and manganese from lixivium of the waste residue of PTA in this paper. As the surplus rate of cobalt and the precipitation rate of manganese were used as assessment indicators ，the effects of the carbonates’ types ，reaction time ，temperature ，stirring speed ，the amount of ammonia and the amount of carbonate on the separation effect of cobalt and manganese were studied on the basis of orthogonal experiments. Experimental results show that ，in the solutions of ammonia-sodium carbonate ，ammonium carbonate and ammonium bicarbonate ，the best reaction condition is: stirring rate 200r/min ，reaction time 8 hours and temperature 20℃. The amount of ammonia is 1.9，1.4 and 1.7 times of chemical stoichiometric coefficient, respectively, and the amount of carbonate is 1.0，1.3 and 1.3 times. The surplus rate of cobalt in these three solutions can reach to 96.0%，99.8% and 99.5%，respectively ，and the precipitation rate of manganese can all reach 100%.资源再生利用。
电芯生产工艺流程英文缩写The Manufacturing Process of Battery CellsBattery cells are the fundamental building blocks of modern energy storage systems, powering a wide range of devices from smartphones to electric vehicles. The manufacturing process of these cells is a complex and precisely engineered sequence of steps that ensures the reliable and efficient production of high-quality energy storage solutions. In this essay, we will explore the key stages of the battery cell manufacturing process, highlighting the importance of each step and the critical factors that contribute to the overall quality and performance of the final product.The manufacturing process of battery cells typically begins with the preparation of the active materials, which are the core components that store and release energy. This stage involves the careful selection, processing, and blending of various chemical compounds, such as lithium, cobalt, nickel, and manganese, to create the active material formulations that will be used in the electrodes. The active materials are then coated onto thin metal foils, such as copper and aluminum, to form the anode and cathode, respectively.The next step in the process is the assembly of the battery cell components. This involves the precise alignment and stacking or winding of the anode, cathode, and separator layers, which are essential for the efficient transfer of ions between the electrodes during charge and discharge cycles. The separator, typically made of a porous polymer material, acts as a barrier to prevent direct contact between the anode and cathode, while still allowing the flow of ions.Once the cell components are assembled, the battery cell is sealed within a protective casing, usually made of metal or a polymer-based material. This step, known as cell casing, is crucial for ensuring the long-term stability and safety of the battery cell, as it protects the internal components from environmental factors such as moisture, oxygen, and mechanical stress.The next critical stage in the manufacturing process is the electrolyte filling and formation cycling. The electrolyte, a solution of lithium salts in organic solvents, is carefully introduced into the sealed cell, allowing for the efficient transfer of ions between the electrodes. The formation cycling process then involves the initial charging and discharging of the battery cell, which helps to activate the active materials and establish the necessary electrochemical reactions within the cell.After the formation cycling, the battery cell undergoes a series ofquality control and testing procedures to ensure its compliance with safety standards and performance specifications. These tests may include measurements of capacity, voltage, internal resistance, and cycle life, as well as more advanced analyses, such as thermal abuse testing and electrochemical impedance spectroscopy.Finally, the tested and approved battery cells are packaged and prepared for distribution to various applications, such as consumer electronics, electric vehicles, and stationary energy storage systems. The packaging process may involve the integration of the individual cells into larger battery modules or packs, which can provide additional features, such as advanced battery management systems and thermal management solutions.Throughout the entire manufacturing process, strict quality control measures and continuous process improvements are implemented to maintain the highest standards of safety, reliability, and performance. The use of advanced manufacturing technologies, such as robotic automation, data analytics, and Industry 4.0 principles, further enhances the efficiency and precision of the battery cell production, ensuring that the final products meet the ever-increasing demands of the modern energy landscape.In conclusion, the manufacturing process of battery cells is a complex and multifaceted endeavor that requires a deepunderstanding of materials science, electrochemistry, and precision engineering. By carefully orchestrating each step of the process, battery manufacturers are able to produce high-quality energy storage solutions that power a wide range of essential technologies and contribute to the ongoing transition towards a more sustainable and energy-efficient future.。
茂金属催化剂英文Metal catalysts are essential components in many chemical processes. Among them, transition metals and their compounds have found widespread use as catalysts due to their unique chemical properties. Among the various transition metals, platinum and palladium have been widely used in many industrial applications for catalysis. However, the high cost and limited availability of these metals have prompted researchers to explore other alternatives.One of the alternatives to platinum and palladium is the so-called "green metal" catalysts. These catalysts are based on earth-abundant metals such as iron, cobalt, and nickel. Among them, iron-based catalysts have attracted significant attention due to their inexpensive and non-toxic nature. One example of an iron-based catalyst is the so-called "Fe-Mo" catalyst, which is composed of iron and molybdenum metals.The Fe-Mo catalyst is an effective catalyst for various chemical reactions, such as the oxidation of alcohols, aldehydes, and amines. It has also been used in the synthesis of various organic compounds, such as lactams, ketones, and esters. The catalyst is prepared by combining iron and molybdenum precursors in a reducing atmosphere. The resulting powder is then calcined and reduced under hydrogen gas to form the catalytically active Fe-Mo phase.Another type of metal catalyst is the so-called "noble metal-free" catalysts. These catalysts are based on non-noble metals such as copper, cobalt, and nickel. Among them,cobalt-based catalysts have been extensively studied forvarious catalytic reactions. One example of a cobalt-based catalyst is the "CoMnP" catalyst, which is composed of cobalt, manganese, and phosphorus.The CoMnP catalyst is an effective catalyst for various chemical reactions, such as the hydrogenation of nitroarenes, the dehydrogenation of alkanes, and the hydrodeoxygenation of biomass-derived compounds. The catalyst is prepared by the impregnation of cobalt and manganese precursors onto asupport material, followed by annealing in a reducing atmosphere. The resulting powder is then activated under hydrogen gas to form the catalytically active CoMnP phase.In conclusion, metal catalysts play an essential role in various chemical processes. However, the high cost andlimited availability of noble metals have promptedresearchers to explore alternative metal catalysts. Among them, iron and cobalt-based catalysts have shown promising results for various catalytic reactions. The development of these "green" and "noble metal-free" catalysts will undoubtedly have a significant impact on the chemicalindustry and the environment.。
盖板c o v e r b o a r d 底板s o l e p i e c e 钢珠s t e e l b a l l 压钢珠p r e s s s t e e l b a l l 防爆阀v a l v e p r e v e n t i n g e x p l o s i o n大电流(倍率)放电discharge in high rate current标称电压Normal voltage标称容量normal capacity放电容量discharge capacity充电上限电压limited voltage in charge放电下限电压terminating voltage in discharge恒流充电constant current charge恒压充电constant voltage charge恒流放电constant current discharge放电曲线discharge curve充电曲线charge curve放电平台discharge voltage plateau容量衰减capacity attenuation起始容量initial discharge capacity流水线pipelining传送带carrying tape焊极耳welding the current collector卷绕wind叠片layer贴胶带stick tape点焊spot welding超声焊ultrasonic weldingThe terminating voltage in discharge of the battery is volt. The limited voltage in charge of the battery is volt.三元素Nickle-Cobalt-Manganese Lithium Oxidethree elements materials钴酸锂Cobalt Lithium Oxide锰酸锂Manganese Lithium Oxide石墨graphite烘箱oven真空烘箱vacuum oven搅拌机mixing devicevacuum mixing device涂布机coating equipment裁纸刀paper knife ,,,,,,cutting knife分条机equipment for cutting big piece to much pieces 辊压机roll press equipment电阻点焊机spot welding machine超声点焊机ultrasonic spot welding machine卷绕机winder自动叠片机auto laminating machine激光焊机laser welding machine注液机infusing machine真空注液机vacuum infusion machine预充柜pre-charge equipment化成柜formation systems分容柜grading systems测试柜testing systems内阻仪battery inner resistance tester万用表multimeter转盘式真空封口机turntable type vacuum sealing machine自动冲膜机automatic aluminum membrane shaper。
锂电池正极材料和前驱体Lithium-ion batteries play a crucial role in powering many of our electronic devices, from smartphones to electric vehicles. One of the key components of these batteries is the positive electrode material, which is responsible for storing and releasing lithium ions during charge and discharge cycles. The development of high-performance positive electrode materials is essential for improving the energy density, power output, and lifespan of lithium-ion batteries.锂离子电池在许多电子设备中发挥着至关重要的作用，从智能手机到电动汽车。
其中一个关键组件是正极材料，它在充放电周期中负责储存和释放锂离子。
高性能正极材料的开发对于提高锂离子电池的能量密度、功率输出和寿命至关重要。
There are various types of positive electrode materials that have been investigated for lithium-ion batteries, including lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), and lithium nickel manganese cobalt oxide (LiNixMnyCozO2). Each material has its own unique set of characteristics, such as energy density, cycling stability,and cost. Researchers are continuously exploring new materials and formulations to improve the performance of lithium-ion batteries.有各种类型的正极材料被研究用于锂离子电池，包括氧化钴锂(LiCoO2)、磷酸铁锂(LiFePO4)和氧化镍锂锰钴(LiNixMnyCozO2)。
第30卷第3期2021年6月Vol.30,No.3June2021矿冶MINING AND METALLURGYdoi:10.3969/j.issn.1005-7854.2021.03.005碳热还原一浸出法回收废旧锂电池中的镰、钻、猛代云1邓朝勇1吴浩彳(1.稀美资源(广东)有限公司，广东清远513055；2.广东佳纳能源科技有限公司，广东清远513056)摘要：废旧锂离子电池正极材料含有大量的有价金属且市场拥有量大，目前的回收工艺具有流程长、酸消耗高、锂的直收率低等问题。
利用价格低廉的工业焦粉与三元正极材料混合加热可以实现粘结剂和正极材料的有效分离，同时将正极材料还原回收。
通过碳热还原将废旧锂离子电池正极材料中的锂转化为可溶性碳酸盐，首先利用水浸过程分离出锂，接下来采用硫酸浸出工艺对废旧锂离子电池正极材料中的镰、钻、猛三种元素进行浸出，研究了碳热还原条件和水浸条件对锂浸出的影响，最后将水浸渣进行硫酸浸出分离鎳、钻、猛。
结果表明，在碳热还原温度6509、还原时间100min.水浸温度259、水浸液固比(mL/g)12.搅拌速度100r/min.水浸时间120min时，锂的浸出率达到最大，为91.61%；在硫酸浓度2.0mol/L.搅拌转速为200r/min.液固比(mL/g)为9、浸出温度75匸、浸出时间90min时，可以获得一个较优的镰、钻、猛浸出率，此条件下的镰、钻、猛浸出率分别为95.83%、96.22%.9&02%。
碳热还原一水浸一硫酸浸出工艺是一种较为高效的回收三元废旧锂离子电池中有价金属的工艺。
关键词：废旧三元锂离子电池；正极材料；碳热还原；水浸；硫酸浸出中图分类号：X758文献标志码：A文章编号：1005-7854(2021)03-0024-07Recovery of Ni,Co and Mn from cathode materials of spent lithium ion batteries by carbothermal reduction and leaching methodDAI Yun1DENG Chao-yong1WU Hao2(1.Ximei Resources(Guangdong)Limited,Qingyuan513055,Guangdong,China；2.Guangdong Jiana Energy Technology Co.Ltd.,Qingyuan513056,Guangdong,China)Abstract:There is a large amount of spent cathode materials for lithium-ion batteries in the market and they contain a lot of valuable metals・The current recycling process has many problems,such as long process,high acid consumption and low direct yield of lithium・The effective separation of binder and cathode material can be achieved by mixing and heating the cheap industrial coke powder with ternary cathode material,and the cathode material can be recovered at the same time.Lithium in spent lithium-ion battery cathode materials was converted into soluble carbonate by carbothermal reduction.Firstly,lithium was separated by water leaching process,and then nickel,cobalt and manganese in spent lithium-ion battery cathode materials were leached by sulfuric acid leaching process・Finally,the leaching residue was leached with sulfuric acid to separate nickel?cobalt and manganese.The results show that when the carbothermal reduction temperature is650°C,the carbothermal reduction time is100min,the water leaching temperature is25°C,the liquid-solid ratio is12mL/g,the stirring speed is100r/min,and the water leaching time is120min,the leaching rate of lithium reaches the maximum,which is91・61%・When收稿日期：2021-03-17基金项目：广东省重点实验室专项（2020年粤财科教[2020]50号）；清远市科技计划项目（清科函[2019]126号300）第一作者：代云，学士，高级工程师，主要从事湿法冶金与资源综合回收利用研究。
Hardening and Tempering of Plain Carbon Steel Plain carbon steel has been valued from early time because of certain properties. this soft silver-gray metal could be converted into a superhard substance that would cut glass and many other substance，sincluding itself when soft. Furthermore，its hardness could be controlled. This converting of carbon steel into a steel of useful hardnessis done with different heat treatments，two of the most important of which are hardening and tempering (drawing)，what ' s theapinl carbon steel and which you will investigate in this lesson.Plain Carbon SteelIn simple terms，a plain carbon steel may be said to be an alloy of iron and carbon containing less than 1.7% carbon. In practic，e however，these steels rarely contain more than about 1.4% carbon and other elements are also present，either as deliberate additions(e.g. manganese) or as impurities(e.g. sulphur and phosphorus).Plain carbon steels may be classified into three main groups:1.Low carbon steel (mild steel) containing less than 0.3% carbon.2.Medium carbon steel containing 0.3% to 0.6% carbon.3.High carbon steel containing 0.6% to 1.4% carbon.Low carbon steelLow carbon steels may be sub-divided into:1.Dead mild steel containing 0.05% to 0.10% carbonIn the manufacture of this materia，l complete deoxidation is not carried out and it is made as rimming steel. It is produced as hot and cold worked she，etstrip，rod，wire and tube，and is available in the hot-worked or process annealed condition for the deep drawing of sheet，but the strength is low. This type of steel is usedfor the manufacture of motorcar bodies，refrigerators，washing machines，office furniture ，pressings，rivets and nails.2.Carburising steels containing 0.1% to 0.2% carbonThe strength and hardness of these steels is lo，w but a hard surface can be obtained by carburizing in order to combine a wear-resistant surface with tough core properties. The ductility makes rapid machining difficult unless the Mn and S content is increased by using a shlphur content of 0.2% to 0.3% with about 1% manganese.3.Constructional mild steels containing 0.2% to 0.3% carbonAs the carbon content is raised above 0.2% ，the strength increases into the range required for constructional purposes，but the ductility decreases. The fabrication qualities (working and welding characteristics) of this material are very good. The steel is hot-rolled into plate for making boilers ，ships and vehicles，and also into sections (e. g. girders，beams，joists) for use in bridges and buildings. The steel is often used in the hot-rolled condition ，but the smaller sized material may be normalized.It has been estimated that about 90% (by weight) of all steel used is of this low carbon classification.Medium Carbon SteelsMedium carbon steels are often quenched-hardened and fully tempered to give good strength with maximum toughness, which are the properties required of components such as shafts, gears and connecting rods. Steels containing 0.4% to 0.5% carbon may also be surface hardened by localized heating and quenching.High Carbon SteelHigh carbon steel are quench hardened and lightly tempered to give high hardness with only limited toughness. Material in this classification is mainly used for making fairly small, relatively inexpensive cutting tools so that the group as a whole is known as carbon tool steel. Steels containing 0.6% to 0.8% carbon are used for making dies , springs , wire ropes and railway types . Many different kinds of tools are made form higher carbon steels as indicated below .Carbon% Type of tool0.8—1.0 Cold chisels, shear blades, punches, hammers1.0—1.2 Files, axes, saws, knives1.2—1.4 Razors, drills, wood-cutting and metal-cutting toolsLimitations of Plain Carbon SteelsPlain carbon steels have many limitations including the following:(1)If reasonable toughness and ductility are required, the maximum tensile strength2 obtainable is about 700N/mm .(2)Large sections cannot be effectively hardened, thus restricting their use torelatively thin sections.(3)Water quenching is necessary for full hardening with consequent risk of distortion and cracking.(4)Rapid softening above about 300 Co limits their use for high-speed metal cutting.(5)Poor resistance to corrosion and to oxidation at elevated temperatures.To overcome these limitations, additional elements are added to the steel togive alloy steels with specific properties. The main alloying elements include manganese, nickel, chromium, molybdenum, tungsten, vanadium, cobalt and silicon. Hardening of Plain Carbon SteelAs steel is heated above the lowed critical temperature of 1330F(72o1C)，the carbon that was in the from of layers of iron carbide in pearlite begins to dissolve in the iron and from a solid solution called austenite. When this solution of iron and carbon is suddenly cooled or quenched，a new microstructure is formed. This is called martensite. Martensite is very hard and brittle ，having a much higher tensile strength than the steel with a pearlite microstructure. It is quite unstable，however，and must be tempered(drawn) to relieve internal stresses in order to have the ductility and toughness needed to be useful. AISIC1095，commonly known as water-hardening tool(W1) steel ，will begin to show hardness when quenched from a temperature just over 1330F(72o1C) but will not harden at all if quenched from a temperature lower than 1330F(721oC). This steel will become as hard as it can get when heated to 1450(78o8C) and quenched in water. This quenching temperature changes as the carbon content changes.It should be 50F(28oC) above the upper critical temperature for carbon steels containing less than 0.83 percent carbon. The reason carbon steel，less than eutectoid，should be heated above the upper critical temperature is that the ferrite is not all transformed into austenite below this point ，and when quenched，is retained in the martensitic structure. The retained ferrite causes brittleness even after tempering.Low carbon steels such as AISI1020 will no，t for all practical purposes，harden when they are heated and quenched. Oil-and air-hardening steels have a higher hardenability and do not have to be quenched as rapidly as plain carbon steels. Consequen，tlythey are deeper hardening than water hardening types，which must becooled to 200F(93oC) within 1 or 2 seconds. Plain carbon steels containing 0.83 percent carbon can get as hard (RC67) as any plain carbon steel containing more carbon.Tempering of Plain Carbon SteelTempering，or drawing，is a process of reheating a steel part that has been previously to transform some of the hard martensite into softer structures. The higher the tempering temperature used，the more martensite is transformed，and the softer and tougher(less brittle) the piece becomes. Therefore，tempering temperatures are specified according to the strength and ductility desired. Mechanical properties charts，which may be found in steel manufacturers handbooks and catalog，s give these data for each type of alloy steel.temperature and holding it there for a length of time，then cooling it in airor water. A part can be tempered in a furnace or oven by bringing it to the required Some tool steels should be cooled rapidly after tempering to avoid temper brittleness.Tempering should be done as soon as possible after hardening. The part should not be allowed to cool completely ，since untempered it contains very high internal stresses and tends to split or crack. Tempering will relieve the internal stresses. A hardened part left overnight without tempering may develop cracks by itself. Classification of Heat Treating ProcessesIn some instances，heat treatment procedures are clear cut in terms of technique and application ．whereas in other instances，descriptions or simple explanations are insufficient because the same technique frequently may be used to obtain different objectives．For example，stress relieving and tempering are often accomplished with the same equipment and by use of identical time and temperature cycles．The objectives，however，are different for the two processes．The following descriptions of the principal heat treating processesare generally arrangedNormalizing usually is used as a conditioning treatment，notably for refining the grains of steels that have been subjected to high temperatures forforging or other hot working Operations.The normalizing process usually is succeeded by another heat treating operation such as austenitizing for hardenin，g annealing，ortempering．Annealing IS a generic term denoting a heat treatment that consisis of heatingto and holding at a suitable temperature followed by cooling at a suitable rate．It is used primarily to soften metallic materials，but also to simultaneously produce desired changes in other properties or in microstructure.The purpose of such changes may be，but is not confined to，improvement Of machinability ，facilitation ofcold work(known as in —process annealing)，improvement of mechanical orelectrical properties，or to increase dimensional stability．When applied solely to reIieve stresses，it commonly is called stress—relief annealing，synonymous with stress relieving．When the term “ annealing a”pipslied to ferrous alloys withoutqualification,full annealing is implied This is achieved by heating above the alloy ' tisansformation temperature，then applying a cooling cycle which provides maximum softness．This cycle may vaiy widely，depending on composition and chaiacteiistics of the specific allo．yQuenching is the iapid cooling of a steel oi alloy fiom the austenitizing tempeiatuie by'immeising the woikpiece in a liquid oi gaseous mediu．mQuenching media commonly used include watei，5%biine，5％caustic in an aqueous solution，oil，polymei solutions，oi gas(usually aii oi nitiogen ).Selection of a quenching medium depends laigely on the haidennability of the mateiial and the mass of mateiial being tieated (piincipally section thickness).The cooling capabilities of the above-listed quenching media vaiy gieatly. In selecting a quenching medium, it is best to avoid a solution that has moie cooling powei than is needed to achieve the iesults, thus minimizing the possibility of ciacking and waipage of the paits being tieated. Modifications of the teim quenching include diiect quenching, fog quenching, hot quenching, inteiiupted quenching selective quenching, spiay quenching, and time quenching.Tempeiing. In heat tieating of feiious alloys, tempeiing consists of ieheating the austenitized and quench-haidenedsteel oi iion to some pieselectedtempeiatuie that is below the lowei tiansfoimation tempeiatuie (geneially below 1300 F oi 705). Tempeiing offeis a means of obtaining vaiious combinations of mechanical piopcities. Tempeiing tempeiatuies used foi haidened steels aie often no highei than 300 F(150).The teim “tempeiings”hould not be confused with eithei piocess annealing oi stiess ielieving. Even though time and tempeiatuie cycles foi the thiee piocesses may be the same, the conditions of the mateiials being piocessed and the objectives may be diffeient.Stiess ielieving. Like tempeiing, stiess ielieving is always done by heating to some tempeiatuie below the lowei tiansfoimation steels and iions. Foi nonfeiious metals, the temperature may vary form slightly above room temperature to several hundred degrees, depending on the alloy and the amount of stress relief that is desired.The primary purpose of stress relieving is to relieve stresses that have been imparted to the workpiece form such processesas forming, rolling, machining or welding. The usual procedure is to heat workpieces to the pre-established temperature long enough to reduce the residual stresses(this is a time-and temperature-dependentoperation) to an acceptable level; this is followed by cooling at arelatively slow rate to avoid creation of new stresses.普通碳素钢的淬火与回火很久以前，普通碳素钢就因其某些性能而受到重视，这种银灰色的软金属能够转变呈一种超硬的物质，该物质可以切削玻璃和许多其他物质，包括处于软状态的该金属本身。
托福TPO10阅读原文及答案解析Part1托福TPO作为托福的模考工具，它的题目对于我们备考托福很有参考价值，为了帮助大家备考，下面小编给大家整理了托福TPO10阅读原文及答案解析Part1，望喜欢！托福TPO10阅读原文Part1Chinese PotteryChina has one of the world's oldest continuous civilizations-despite invasions and occasional foreign rule. A country as vast as China with so long-lasting a civilization has a complex social and visual history, within which pottery and porcelain play a major role.The function and status of ceramics in China varied from dynasty to dynasty, so they may be utilitarian, burial, trade-collectors', or even ritual objects, according to their quality and the era in which they were made. The ceramics fall into three broad types-earthenware, stoneware, and porcelain-for vessels, architectural items such as roof tiles, and modeled objects and figures. In addition, there was an important group of sculptures made for religious use, the majority of which were produced in earthenware.The earliest ceramics were fired to earthenware temperatures, but as early as the fifteenth century B.C., high-temperature stonewares were being made with glazed surfaces. During the Six Dynasties period (AD 265-589), kilns in north China were producing high-fired ceramics of good quality. Whitewares produced in Hebei and Henan provinces from the seventh to the tenth centuries evolved into the highly prized porcelains of the Song dynasty (AD. 960-1279), long regarded as one of the high points in the history of China's ceramic industry.The tradition of religious sculpture extends over most historical periods but is less clearly delineated than that of stonewares or porcelains, for it embraces the old custom of earthenware burial ceramics with later religious images and architectural ornament. Ceramic products also include lead-glazed tomb models of the Han dynasty, three-color lead-glazed vessels and figures of the Tang dynasty, and Ming three-color temple ornaments, in which the motifs were outlined in a raised trail of slip-as well as the many burial ceramics produced in imitation of vessels made in materials of higher intrinsic value.Trade between the West and the settled and prosperous Chinese dynasties introduced new forms and different technologies. One of the most far-reaching examples is the impact of the fine ninth-century AD. Chinese porcelain wares imported into the Arab world. So admired were these pieces that they encouraged the development of earthenware made in imitation of porcelain and instigated research into the method of their manufacture. From the Middle East the Chinese acquired a blue pigment-a purified form of cobalt oxide unobtainable at that time in China-that contained only a low level of manganese. Cobalt ores found in China have a high manganese content, which produces a more muted blue-gray color. In the seventeenth century, the trading activities of the Dutch East India Company resulted in vast quantities of decorated Chinese porcelain being brought to Europe, which stimulated and influenced the work of a wide variety of wares, notably Delft. The Chinese themselves adapted many specific vessel forms from the West, such as bottles with long spouts, and designed a range of decorative patterns especially for the European market.Just as painted designs on Greek pots may seem today to bepurely decorative, whereas in fact they were carefully and precisely worked out so that at the time, their meaning was clear, so it is with Chinese pots. To twentieth-century eyes, Chinese pottery may appear merely decorative, yet to the Chinese the form of each object and its adornment had meaning and significance. The dragon represented the emperor, and the phoenix, the empress; the pomegranate indicated fertility, and a pair of fish, happiness; mandarin ducks stood for wedded bliss; the pine tree, peach, and crane are emblems of long life; and fish leaping from waves indicated success in the civil service examinations. Only when European decorative themes were introduced did these meanings become obscured or even lost.From early times pots were used in both religious and secular contexts. The imperial court commissioned work and in the Yuan dynasty (A.D. 1279-1368) an imperial ceramic factory was established at Jingdezhen. Pots played an important part in some religious ceremonies. Long and often lyrical descriptions of the different types of ware exist that assist in classifying pots, although these sometimes confuse an already large and complicated picture.Paragraph 2: The function and status of ceramics in China varied from dynasty to dynasty, so they may be utilitarian, burial, trade-collectors', or even ritual objects, according to their quality and the era in which they were made. The ceramics fall into three broad types-earthenware, stoneware, and porcelain-for vessels, architectural items such as roof tiles, and modeled objects and figures. In addition, there was an important group of sculptures made for religious use, the majority of which were produced in earthenware.托福TPO10阅读题目Part11.The word "status" in the passage is closest in meaning to○ origin○ importance○ quality○ design2. According to paragraph 2, which of the following is true of Chinese ceramics?○ The function of ceramics remained the same from dynasty to dynasty.○ The use of ceramics as trade objects is better documented than the use of ceramics as ritual objects.○ There was little variation in quality for any type of ceramics over time.○ Some religious sculptures were made using the earthenware type of ceramics.Paragraph 3: The earliest ceramics were fired to earthenware temperatures, but as early as the fifteenth century B.C., high-temperature stonewares were being made with glazed surfaces. During the Six Dynasties period (AD 265-589), kilns in north China were producing high-fired ceramics of good quality. Whitewares produced in Hebei and Henan provinces from the seventh to the tenth centuries evolved into the highly prized porcelains of the Song dynasty (AD. 960-1279), long regarded as one of the high points in the history of China's ceramic industry. The tradition of religious sculpture extends over most historical periods but is less clearly delineated than that of stonewares or porcelains, for it embraces the old custom of earthenware burial ceramics with later religious images and architectural ornament. Ceramic products also include lead-glazed tomb models of the Han dynasty, three-color lead-glazed vessels and figures of theTang dynasty, and Ming three-color temple ornaments, in which the motifs were outlined in a raised trail of slip-as well as the many burial ceramics produced in imitation of vessels made in materials of higher intrinsic value.3. The word "evolve" in the passage is closest in meaning to○ divided○ extended○ developed○ vanished4. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.○ While stonewares and porcelains are found through out most historical periods, religious sculpture is limited to the ancient period.○ Religious sculpture was created in most periods, but its history is less clear than that of stonewares or porcelains because some old forms continued to be used even when new ones were developed.○ While stonewares and porcelains changed throughout history, religious sculpture remained uniform in form and use.○ The historical development of religious sculpture is relatively unclear because religious sculptures sometimes resemble earthenware architectural ornaments.5. Paragraph 3 supports all of the following concerning the history of the ceramic industry in China EXCEPT:○ The earliest high-fired ceramics were of poor quality.○ Ceramics produced during the Tang and Ming d ynasties sometimes incorporated multiple colors.○ Earthenware ceramics were produced in China before stonewares were.○ The Song dynasty period was notable for the production of high quality porcelain ceramics.Paragraph 4: Trade between the West and the settled and prosperous Chinese dynasties introduced new forms and different technologies. One of the most far-reaching examples is the impact of the fine ninth-century AD. Chinese porcelain wares imported into the Arab world. So admired were these pieces that they encouraged the development of earthenware made in imitation of porcelain and instigated research into the method of their manufacture. From the Middle East the Chinese acquired a blue pigment-a purified form of cobalt oxide unobtainable at that time in China-that contained only a low level of manganese. Cobalt ores found in China have a high manganese content, which produces a more muted blue-gray color. In the seventeenth century, the trading activities of the Dutch East India Company resulted in vast quantities of decorated Chinese porcelain being brought to Europe, which stimulated and influenced the work of a wide variety of wares, notably Delft. The Chinese themselves adapted many specific vessel forms from the West, such as bottles with long spouts, and designed a range of decorative patterns especially for the European market.6. The word "instigate" in the passage is closest in meaning to○ improved○ investigated○ narrowed○ caused7. According to paragraph 4, one consequence of the tradeof Chinese ceramics was○ the transfer of a distinctive blue pigment from China to the Middle East○ an immediate change from earthenware production to porcelain production in European countries○ Chinese production of wares made for the European market○ a decreased number of porcelain vessels available on the European marketParagraph 5: Just as painted designs on Greek pots may seem today to be purely decorative,whereas in fact they were carefully and precisely worked out so that at the time, their meaning was clear, so it is with Chinese pots. To twentieth-century eyes, Chinese pottery may appear merely decorative, yet to the Chinese the form of each object and its adornment had meaning and significance. The dragon represented the emperor, and the phoenix, the empress; the pomegranate indicated fertility, and a pair of fish, happiness; mandarin ducks stood for wedded bliss; the pine tree, peach, and crane are emblems of long life; and fish leaping from waves indicated success in the civil service examinations. Only when European decorative themes were introduced did these meanings become obscured or even lost.8. The word "whereas" in the passage is closest in meaning to○ while○ previously○ surprisingly○ because9. In paragraph 5, the author compares the designs onChinese pots to those on Greek pots in order to○ emphasize that while Chinese pots were decorative, Greek pots were functional○ argue that the designs on Chinese pots had specific meanings and were not just decorative○ argue that twentieth-century scholars are better able to understand these designs than were ancient scholars ○ explain how scholars have identified the meaning of specific images on Chinese pots10. Which of the following is mentioned in paragraph 5 as being symbolically represented on Chinese ceramics?○ Chinese rulers○ love of homeland○ loyally to friends○ success in trade11. Paragraph 5 suggests which of the following about the decorations on Chinese pottery?○ They had more importance for aristocrats than for ordinary citizens.○ Their significance may have remained clear had the Chinese not come under foreign influence.○ They contain some of the same images that appear on Greek pots○ Their significance is now as clear to twentieth century observers as it was to the early Chinese.Paragraph 6: From early times pots were used in both religious and secular contexts. The imperial court commissioned work and in the Yuan dynasty (A.D. 1279-1368) an imperial ceramic factory was established at Jingdezhen. Pots played an important part in some religious ceremonies. Long and oftenlyrical descriptions of the different types of ware exist that assist in classifying pots, although these sometimes confuse an already large and complicated picture.12. The word "these" in the passage refers to○ religious ceremonies○ descriptions○ types of ware○ potsParagraph 4: Trade between the West and the settled and prosperous Chinese dynasties introduced new forms and different technologies. One of the most far-reaching examples is the impact of the fine ninth-century AD. Chinese porcelain wares imported into the Arab world. ■So admired were these pieces that they encouraged the development of earthenware made in imitation of porcelain and instigated research into the method of their manufact ure. ■From the Middle East the Chinese acquired a blue pigment-a purified form of cobalt oxide unobtainable at that time in China-that contained only a low level of manganese. Cobalt ores found in China have a high manganese content, which produces a more muted blue-gray color. ■In the seventeenth century, the trading activities of the Dutch East India Company resulted in vast quantities of decorated Chinese porcelain being brought to Europe, which stimulated and influenced the work of a wide variety of wares, notably Delft. ■The Chinese themselves adapted many specific vessel forms from the West, such as bottles with long spouts, and designed a range of decorative patterns especially for the European market.13. Look at the four squares [■]that indicate whe re the following sentence could be added to the passage.Foreign trade was also responsible for certain innovations incoloring.Where could the sentence best fit?14.Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Ceramics have been produced in China for a very long time.●●●Answer choices○ The Chinese produced earthenware, stoneware, and porcelain pottery and they used their ceramics for a variety of utilitarian, architectural, and ceremonial purposes.○ The shape and decoration of ceramics produced for religious use in China were influenced by Chinese ceramics produced for export.○ As a result of trade relations, Chinese ceramic production changed and Chinese influenced the ceramics production of other countries.○ Chinese burial ceramics have the longest and most varied history of production and were frequently decorated with written texts that help scholars date them.○ Before China had contact with the West, the meaning of various designs used to decorate Chinese ceramics was well understood.○ Ceramics made in imperial factories were used in bothreligious and non-religious contexts.托福TPO10阅读答案Part1参考答案：1. ○22. ○43. ○34. ○25. ○16. ○47. ○38.○19. ○210. ○111. ○212. ○213. ○214. The Chinese producedAs a result of tradeBefore China had contact托福TPO10阅读翻译Part1参考翻译：中国的陶瓷尽管中国曾饱受入侵，偶尔丧失主权受制于外国，她仍然拥有世界上最源远流长的文明。
金属元素与人体（Metal elements and the human body）The so-called trace elements, in environmental geochemistry, refers to only 0.01% of the earth's components of more than 60 kinds of elements, their content is generally between 1 * 10-8 to 1 * 10-88. In the medical field, from the structure of the human body, accounting for less than 1/10000 of the total weight of the human body, that is, trace elements.Trace elements in the human body content is very small, less than 5/10000 of the total weight. Such as iron, zinc, copper, manganese, chromium, selenium, vanadium, iodine and so on. With the development of science, people's knowledge is expanding, and the number of these trace elements will increase.The main functions of trace elements in human body are:1, carrying constant elements, bringing a large number of elements to various tissues.2 acts as the active center of various enzymes in the organism and promotes metabolism. Enzymes are an essential catalyst in many chemical reactions in living organisms, and many trace elements are components or activators of enzymes. For example, zinc is involved in the activity or structure of more than 200 enzymes.3, participate in the role of various hormones in vivo. Such as zinc can promote the function of sex hormones, chromium can promote the role of islet.Iron. Iron in the human body is about 4 - 5 grams. The functionof iron in the body is mainly involved in the formation of hemoglobin and promote hematopoiesis. The hemoglobin content is about 72%. Iron is found in spinach, lean meat, yolk, and animal liver.Copper. Normal adults contain 100 - 200 milligrams of copper. Its main function is to participate in the process of hematopoiesis, enhance disease resistance and participate in the formation of pigments. Copper in the liver, kidney, fish, shrimp, clams in higher content; fruit juice, brown sugar also has a certain content.Zinc. It plays an important role in many physiological functions of human body. Participates in the synthesis of many enzymes; accelerates the growth and development; strengthens the wound tissue regeneration ability; strengthens the resistance; promotes the sexual function. Zinc in fish, meat, animal liver and kidney content is higher.Fluoride. It is the normal component of bones and teeth. It can prevent dental caries and prevent osteoporosis in the elderly. More fluoride content of food, food (wheat, rye flour), fruit, tea, meat, vegetables, tomatoes, potatoes, carp, beef and so on.Se. Adults need about 0.4 milligrams per day. Selenium has antioxidant, protective function of red blood cells, and found the role of cancer prevention. Selenium is abundant in wheat, corn, Chinese cabbage, pumpkin, garlic and seafood.Iodine. Play a physiological role through thyroxine, such aspromoting protein synthesis, activating more than 100 enzymes, regulating energy conversion, accelerating growth and development, and maintaining the structure of the central nervous system. Iodine, kelp, seaweed, sea fish, sea salt and so on are rich in content.Cobalt element. Is an important component of vitamin B12. Cobalt plays an important role in protein, fat, carbohydrate metabolism, hemoglobin synthesis, and can dilate blood vessels and lower blood pressure. But excessive cobalt can cause excessive red blood cells, can also cause gastrointestinal dysfunction, deafness, myocardial ischemia.Chromium. Can help insulin play a role in preventing atherosclerosis, promoting protein metabolism synthesis, and promote growth and development. But when the chromium content increases, such as long-term inhalation of chromate powder, can induce lung cancer.In view of this, trace elements are especially important for the human body, but too little intake and too little can cause disease. At present, many local diseases and some tumors are related to trace elements.With the development of society and people industrialized lifestyle changes also affect the balance of trace elements in the human body and cause many diseases, such as breastfeeding problems caused by the lack of certain trace elements to infant growth abnormalities and disease; food processing is too fine will be lost and some trace elements, which leads to the lack of trace elements in the diet. The diet is too monotonous totrace elements imbalance cause disease; and due to the wide application of aluminum cookware products with the balance of aluminum elements in the human body too much and other trace elements can cause senile dementia.The supplement of trace elements mainly depends on food,So people diet rich and thick collocation, in order to maintain the content of trace elements in normal and balanced, if there is obvious deficiency or excess related diseases should be treated timely seek medical treatment as soon as possible.Trace elements are closely related to human health. Excessive intake, lack or lack of them can lead to abnormal physiological or disease in human body to a certain extent. The most prominent function of trace elements is closely related to vital energy, which can play a large physiological role only as much or less as a match. It is worth noting that these trace elements must be supplied directly or indirectly from the soil. According to scientific research, so far, has been recognized as essential trace elements related to human health and life has 18 kinds, namely iron, copper, zinc, cobalt, manganese, chromium, selenium, iodine, fluorine, nickel, molybdenum, vanadium, tin, silicon, boron, strontium, rubidium, arsenic etc.. Each of these trace elements has its specific physiological function. Although they are very small in the body, they are essential for maintaining certain metabolic processes in the body. Once these essential trace elements are lacking, the body can develop disease and even endanger life. There have been reports abroad: the body contains iron, copper, zinc and reduce the total amount, can weaken the immune mechanism (resistance todisease power), reduce disease resistance, and promote bacterial infection, and the mortality rate is higher after infection. Trace elements play an important role in disease resistance, cancer prevention, longevity and so onIn recent years, more and more attention has been paid to the relationship between trace elements and human health. Food containing certain trace elements should be produced at intervals. The so-called trace elements are for macro elements. There are 11 kinds of macro elements in the human body, also called main elements. They are arranged in order of oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus, potassium, sulfur, sodium, chlorine and magnesium. Among them, oxygen, carbon, hydrogen and nitrogen accounted for 95% of the human body quality, and the rest was about 4%. In addition, trace elements accounted for about 1%. In the essential elements of life, there are 14 kinds of metal elements, among which the content of potassium, sodium, calcium and magnesium account for more than 99% of the total metal elements in the human body, while the other 10 elements are few. Traditionally, an element with a content higher than 0.01% is called a constant element, and an element below this value is called a trace element. If the body lacks a major element, it can cause human dysfunction, but this rarely happens, and the diet generally contains more than enough macro elements. Although trace elements are very few in vivo, they can not be underestimated in the process of life. Without the necessary trace elements, the activity of enzymes will be reduced or completely lost, and the synthesis and metabolism of hormones, proteins and vitamins will also be impaired, and human life processes will be difficult to continue.There are two possible trace elements, nickel and arsenic, each containing 0.1ug/g.At present, the function of certain trace elements is not fully understood, and the following is a brief introduction.Iron is an essential element in the exchange and transport of oxygen in the blood, and many redox systems in the body are inseparable from it. Most of the iron in the body is found in special blood cells. There is no living thing without iron.Zinc and zinc are important elements of life. They act as vital gears in the process of life and transfer substances and exchange energy. It is essential for the formation of multiple proteins. The visual area of the eyeball contains as much as 4% zinc, indicating that it has some special function. Zinc generally exists in food, as long as no partial eclipse, the body is generally not zinc.Copper and copper are also essential for the human body. It is a unique and extremely effective catalyst in the biological system. Copper is an active component of more than 30 enzymes and plays an important regulatory role in the metabolism of the body. Coronary heart disease is reported to be related to copper deficiency. Copper is not readily retained in the body and is often ingested and supplemented. Tea contains traces of copper, so it is good to drink tea often.Chromium is an essential element in the metabolism of sugar or fat that is involved in insulin and is an essential element inmaintaining normal cholesterol.Cobalt and cobalt are a necessary component of vitamin B12 molecules, and B12 is an essential component in the formation of red blood cells.Manganese and manganese are involved in many enzyme catalyzed reactions and are indispensable for all living things.Molybdenum is a component of an enzyme that catalyzes the conversion of purines to uric acid. Molybdenum is also necessary for the exchange of energy. Trace molybdenum is the constituent of eye pigment. There are more molybdenum in pod, cabbage and Chinese cabbage. It is good for the eyes to eat more vegetables.The main function of iodine iodide in the body is to participate in the synthesis of thyroxine. Iodine deficiency can cause hyperthyroidism, iodine deficiency can cause mental retardation in children.Fluorine and fluorine are essential trace elements necessary for the formation of hard bones and for the prevention of dental caries.One of the necessary conditions for human survival is the need to breathe, so that the body must have certain substances that can be combined with oxygen or carbon dioxide to transport oxygen and excrete two oxygen to carbon. These substances are compounds with iron as the backbone.The animal has a complex system, to accept the living environment to the information, and through the information transmission to the nerve commander of life -- the brain, then the brain can make various instructions, the various functional departments in the corresponding reaction indicator. Metals also play a key role in this transmission and command system.The metal has great contribution to the family. Cells are able to recreate and it is the same as the next generation of cells, each cell is because nucleic acid contains a transfer of genetic information, it can indicate a variety of amino acids connected according to the provisions of the order, the formation of the provisions of the protein, the genetic code of the next generation of protein synthesis process is affected by some metal control the.Therefore, more and more people believe that the survival and development of human beings are inseparable from the absorption, transmission, distribution and utilization of these necessary trace elements. In the human body, although the content of trace elements is much less than that of sugar, fat and protein, but their function is no less than sugar, fat and protein. In addition, scientists have learned that the use of these trace elements is definitely not very simple, and not as simple as eating rice, steamed bread, fish, vegetables and fruits. For example, some people have assumed that the center of the molecular structure of vitamin B12 is a cobalt ion, that is, vitamin B12 is a cobalt compound, so if you lack vitamin B12, you should eat a little more cobalt salt. But the fact is not so simple, eating a simple cobalt salt, not only for the treatment of vitamin B12 deficiency symptoms are invalid, butslightly toxic, and only the use of vitamin B12 is really effective. It seems that the use of trace elements is still a great learning.The so-called trace elements, in environmental geochemistry, refers to only 0.01% of the earth's components of more than 60 kinds of elements, their content is generally between 1 * 10-8 to 1 * 10-88. In the medical field, from the structure of the human body, accounting for less than 1/10000 of the total weight of the human body, that is, trace elements.Trace elements in the human body content is very small, less than 5/10000 of the total weight. Such as iron, zinc, copper, manganese, chromium, selenium, vanadium, iodine and so on. With the development of science, people's knowledge is expanding, and the number of these trace elements will increase.Trace elements are closely related to human health. Excessive intake, lack or lack of them can lead to abnormal physiological or disease in human body to a certain extent. The most prominent function of trace elements is closely related to vital energy, which can play a large physiological role only as much or less as a match. It is worth noting that these trace elements must be supplied directly or indirectly from the soil. According to scientific research, 18 essential trace elements related to human health and life have been identified so far,They are iron, copper, zinc, cobalt, manganese, chromium, selenium, iodine, nickel, fluorine, molybdenum, vanadium, tin, silicon, strontium, boron, rubidium, arsenic and so on. Each of these trace elements has its specific physiological function.Although they are very small in the body, they are essential for maintaining certain metabolic processes in the body. Once these essential trace elements are lacking, the body can develop disease and even endanger life. There have been reports abroad: the body contains iron, copper, zinc and reduce the total amount, can weaken the immune mechanism (resistance to disease power), reduce disease resistance, and promote bacterial infection, and the mortality rate is higher after infection. Trace elements play an important role in disease resistance, cancer prevention, longevity and so on.。
