Biocompatibility and preliminary clinical application of HA/HDPE nanocomposites synthetic auditory ossicle

The biocompatibility of the hydroxyapatite/high density polyethtlene（HA/HDPE） nanocomposites synthetic auditory ossicle was evaluated, the percentage of S-period cells was detected by flow cytometry after L929 incubated with extraction of the HA/HDPE nanocomposites, titanium materials of clinical application as the control. Both of them were implanted in the animals and the histopathological evaluations were carried out, and the preliminary clinical trials about HA/HDPE nanocomposites synthetic auditory ossicles were also carried out. The statistical analysis show that there are no statistically significant differences between HA/HDPE test groups and control groups （P〉0.05）, which demonstrates that the HA/HDPE nanocomposites synthetic auditory ossicle has a good biocompatibility and clinical application outlook.     

Bismuth-based materials for rechargeable aqueous batteries and water desalination

Aqueous batteries and seawater desalination have received considerable attention in recent years due to their merits as high safety,environmental friendliness and cost-effectiveness.However,the scarcity of highly match electrode materials hinders their development.The exploration of high performance and low cost electrode materials is crucial for their potential applications.Bismuth(Bi),with high energy density and low redox potential,shows perspective in the field of aqueous batteries and seawater desalination,and significant progress has been achieved in the past decades.In this review,the unique properties and synthetic methods of Bi-based electrodes,as well as their applications are comprehensively summarized and discussed.The commonly used preparation methods of Bibased electrodes,including hydrothermal method,electrodeposition method,etc.,are introduced.Then,the applications of the Bi-based composites in aqueous batteries,such as Ni//Bi batteries and water desalination,are summarized.Finally,the challenges and future research direction of Bi-based materials are proposed.     

In-situ composite Cu-Cr contact cables with high strength and high conductivity

In order to develop a new type of contact cable with high strength and high electrical conductivity, Cu-Cr alloy series were selected as materials and Cu-Cr alloy castings were produced by means of directional solidification continuous casting (DSCC) process. The results show that the fibrillar strengthening phase, 13-Cr, orderly arranges among the copper matrix phase along the wire direction; and a microstructure of in-situ composite forms, which retains the basic property of good conductivity of the copper matrix and meanwhile obtains the strengthening effect of [3-Cr phase. The production technology as well as the mechanical property, electrical property, and synthetic property of the in-situ composite contact cables was discussed.     

Nanoparticles α-Al2O3 prepared by combustion synthesis method

Nanometer α-Al2O3 powders were synthesized by the method of low-temperature combustion synthesis （LCS） with aluminum nitrate nonahydrate and urea as raw materials. The prepared powders were studied by XRD, TG-DTA, FT-IR and TEM. It is found that the average size of particles is 60 -80 nm. The optimal synthetic conditions are obtained, i.e. , the suitable fuel is urea; the molar ratio of oxidizer to fuel is 1 ： 2 and the igniting temperature is 700℃. The results show that the size of particles is governed by synthesizing temperature, the fuel and the molar ratio of oxidizer to fuel. TEM image of the particles collected shows that the crystal habits of particles have a spheric structure and particles are polycrystal.     

Effects of rare earth element lanthanum on the microstructure of copper matrix diamond tool materials

Effects of rare earth element La on the microstructure of Cu matrix diamond tools were researched under the conditions of various materials components and the process parameters in order to improve materials properties. SEM,XPS and X-ray were used to investigate the fracture section, microstructure and the element valence in materials. The results shown that the combination of rare earth element La and transition element Ti is advantageous to the bonding state between diamond particles and matrix, so it can improve the materials properties. Suitable sintering temperature is 790℃.     

NONFERROUS METALS AND PLAIN BEARINGS

The definition of a plain bearing is given.The requirements for bearing materials are pro-posed.The historical perspective and recent development of the bearing materials are intro-duced,and the performances of current bearing materials are compared     

FINE STRUCTURES OF BOTH INTERFACES AND INTERFACIAL REACTION PRODUCTS

The characteristic of interface depending on the atomic structure exerts an inportant,andsometime controlling,influence on performance of the interacial materials.The present paper reviews the main studies on fine structure of both the materials inter-faces and interfacial reaction products in semiconductor uperlattice,metal multilayer ceram-ics and composite materials by mean of selected area electron doffraction patterns and highresolution electron microscopy.The following features of interfaces are reviewed:the orientation relationships;the char-acteristic of steps,facets and ronghness of interfaces;atomic bonding across the interface;thedegree of coherency,the structure of misfit dislocations and elastic relaxations at the inter-faces:the presence of defects at the onterfaces:the structure of the interfacial reaction prod-ucts as well as the reaction kinetics and reaetion mechanism.     

Influence of sample surface condition on nano indentation experiment

The microhardness and elastic modules of the materials were measured using the Nano Indenter II, which is a new measuring system for the mechanical properties of materials on nano-scale. It can determine themicrohardness,elastic modules and other mechanical properties of materials through measuring applied load and depth under indenter tip. The results indicated that surface condition of sample such as the surface roughness affects the experimental precision.     

Development tendencies of moulding and core sands

Further development of the technology for making moulding and core sands will be strictly limited by tough requirements due to protection of the natural environment. These tendencies are becoming more and more tense, so that we will reach a point when even processes, that from technological point of view fulfill high requirements of the foundry industry, must be replaced by more ecologically-friendly solutions. Hence, technologies using synthetic resins as binding materials will be limited. This paper presents some predictable development tendencies of moulding and core sands. The increasing role of inorganic substances will be noticed, including silicate binders with significantly improved properties, such as improved knock-out property or higher reclamation strength. Other interesting solutions might also be moulding sands bonded by geo-polymers and phosphate binders or salts and also binders based on degradable biopolymers. These tendencies and the usefulness of these binders are put forward in this paper.     

Microstructure and frictional properties of 3D needled C/SiC brake materials modified with graphite

The 3D needled C/SiC brake materials modified with graphite were prepared by a combined process of the chemical vapor infiltration,slurry infiltration and liquid silicon infiltration process.The microstructure and frictional properties of the brake materials were investigated.The density and open porosity of the materials as-received were about(2.1±0.1)g/cm3and(5±1)%,respectively.The brake materials were composed of 59%C,39%SiC,and 2%Si(mass fraction).The content of Si in the C/SiC brake materials modified with graphite was far less than that in the C/SiC brake materials without being modified with graphite,and the Si was dispersed.The braking curve of the 3D needled C/SiC modified with graphite was smooth,which can ensure the smooth and comfortable braking.The frictional properties under wet condition of the 3D needled C/SiC modified with graphite showed no fading.And the linear wear rate of the C/SiC modified with graphite was lower than that of the C/SiC unmodified.     

一步法制备氢氧化镁阻燃剂浓度放大实验工艺研究

在由硫酸镁一步制备阻燃型氢氧化镁的工艺基础上,通过工艺条件的调节,实现了硫酸镁溶液浓度由0.25 mol/L放大到1mol/L一步制备氢氧化镁阻燃剂的放大合成工艺,并分别考察了NaOH浓度、反应温度、陈化时间、表面活性剂用量等因素和氢氧化镁样品XRD图(001)面与(101)面衍射峰强度比之间的关系,确定了较佳的工艺条件.     

氢氧化镁阻燃剂研究进展

综述无机氢氧化镁阻燃剂国内外生长现状，论述氢氧化镁阻燃剂的阻燃机理、所需的特殊结构及相应制备技术，对国内制备氢氧化镁阻燃剂的几种工艺路线进行了简单叙述。并提出了由蛇纹石酸浸滤液一步法制备氢氧化镁阻燃剂的新工艺及今后氢氧化镁阻燃剂的发展趋势。     

磷氮阻燃剂 / 纯丙树脂光固化复合膨胀阻燃涂层制备及膨胀行为

目的制备一种新型磷氮类紫外光固化膨胀阻燃涂层,研究磷氮复合成分对阻燃性能及膨胀行为的影响。方法采用丙烯酸正丁酯、甲基丙烯酸甲酯、甲基丙烯酸缩水甘油酯为原料制备环氧侧基聚丙烯酸酯,进一步利用丙烯酸开环环氧制备光固化聚丙烯酸酯,并结合前期所合成的含磷单体磷杂环丙烯酸酯磷酸酯(PGMH)和含氮光固化单体三嗪基四丙烯酸酯(BDAETH)制备光固化膨胀阻燃涂层。通过热重法和红外光谱研究了PGMH对光固化聚丙烯酸酯固化膜热降解机理的影响。采用极限氧指数对涂层阻燃性能进行研究,设计并自制设备对涂层的膨胀行为进行监测。结果随着磷氮复合阻燃剂的添加,涂层在450~480℃之间快速膨胀,其最大单向膨胀度可达14。膨胀碳层隔绝氧气,从而提升阻燃性能,将光固化聚丙烯酸酯的氧指数从19提升到28.5。结论磷氮复合阻燃剂的添加可有效赋予涂层在升温或燃烧过程中的膨胀特性,生成隔绝氧气的膨胀碳层,提高涂层的阻燃性能。     

纳米阻燃母液提高APP/PER/MEL防火涂料耐水性研究

用Solsperse17000超分散剂对纳米二氧化硅和纳米氢氧化镁表面进行包覆改性,再加入树脂、助剂等,经球磨和超声波分散制成纳米阻燃母液,并配制出不同纳米母液含量的纳米改性防火涂料.用透射电子显微镜分析(TEM)和红外光谱分析(FT-IR)研究纳米粒子分散状态和稳定机制.用红外光谱分析(FT-IR)、扫描电子显微镜分析(SEM)、浸水失重曲线分析、差热分析(DTA)研究在水介质中纳米改性防火涂料形貌变化、分子结构变化、水介质传输行为和浸水前后防火涂层的热降解行为.结果表明:4%纳米阻燃母液能有效提高APP/PER/MEL防火涂料的耐水性,且不损害它的热降解行为和防火性能.     

Die structure optimization of equal channel angular extrusion for AZ31 magnesium alloy based on finite element method

Three-dimensional(3D)geometric models with different corner angles(90°and 120°)and with or without inner round fillets in the bottom die were designed.Some important process parameters were regarded as the calculation conditions used in DEFORMT M-3D software,such as stress—strain data of compression test for AZ31 magnesium,temperatures of die and billet,and friction coefficient.Influence of friction coefficient on deformation process was discussed.The results show that reasonable lubrication condition is im...     

钛冶炼氯化镁氨法制备氢氧化镁研究

以某钛冶炼厂中间产品氯化镁为原料,进行了氨法制备氢氧化镁的研究。通过单因素试验及正交试验得到了较合适的工艺条件,所得氢氧化镁符合HG/T3607-2000 I级标准。但由于氨法存在收率低及生产过程不环保,该法仅适于大型建厂来处理大批量的氯化镁,对于处理钛冶炼不定量的氯化镁并不适用。     

我国氢氧化铝阻燃剂现状及发展

氢氧化铝是一种重要的无机阻燃剂,其应用领域和使用量不断扩大.国内利用烧结法精液有机物含量低的优势,大力发展氢氧化铝阻燃填料产业,产品质量和技术水平有了很大的提高.但与国外先进水平相比,仍存在较大差距.本文对国际知名氢氧化铝阻燃剂企业的产品进行了简要介绍,并通过对比国内外氢氧化铝阻燃剂产品现状,找出国内外产品间的差距,并对国内氢氧化铝阻燃剂提出了发展方向及建议.     

Thermal expansion and dimensional stability of unidirectional and orthogonal fabric M40/AZ91D composites

Unidirectional (60%, volume fraction) and orthogonal (50%, volume fraction) M40 graphite fibre reinforced AZ91D magnesium alloy matrix composites were fabricated by pressure infiltration method. The coefficients of thermal expansion (in the temperature range of 20-350 ℃) and dimensional stability (in the temperature range of 20-150 ℃) of the composites and the corresponding AZ91D magnesium alloy matrix were measured. The results show that coefficients of thermal expansion of the composites in longitudinal direction decrease with elevating temperature. The coefficients of thermal expansion (CTE) for unidirectional M40/AZ91D composites and orthogonal M40/AZ91D composites are 1.24×10-6 ℃-1 and 5.71×10-6 ℃-1 at 20 ℃, and 0.85×10-6 ℃-1 and 2.75×10-6 ℃-1 at 350 ℃, respectively, much lower than those of the AZ91D alloy matrix. Thermal cycling testing demonstrates that the thermal stress plays an important role on residual deformation. Thus, a better dimensional stability is obtained for the AZ91D magnesium alloy matrix composites. More extreme strain hysteresis and residual plastic deformation are observed in orthogonally fabric M40 reinforced AZ91D composite, but its net residual strain after each cycle is similar to that of the unidirectional M40/AZ91D composite.     

超疏水铝合金表面的复合制备与性能

铝合金由于易被腐蚀的缺陷限制了其发展,研究表明表面超疏水化能有效地提升其耐腐蚀性能。 文中以铝合金作为基底材料,首先采用激光加工的方法制备微结构表面,然后采用氢氧化钠刻蚀制备超疏水表面。 利用扫描电子显微镜(SEM)、光学轮廓仪、X 射线能谱仪(EDS)、接触角测量仪和电化学工作站对样品表面微观形貌、化学元素组成、 润湿性能和耐腐蚀性能进行表征。 结果表明:激光功率为 30 W,氢氧化钠浓度为 0. 1 M,刻蚀时间为 6 min,该表面的接触角最高为 155. 1°,同时该超疏水表面具有双尺度分层结构,分别是光栅结构与更小一级的蜂窝状结构。 超疏水表面电化学测试表明,腐蚀电位发生左移,为-0. 635 V,自腐蚀电流密度变化更为明显,减小至 1. 68×10^-6 mA·cm^-2 。 该表面耐腐蚀性能显著增加。     

Tensile properties of hot rolled Mg_(97)Zn_1Y_2 alloy sheets at elevated temperatures

The elevated temperature tensile properties of Mg97Zn1Y2 magnesium alloy sheets, hot rolled at 390, 420 and 450 ℃ respectively, were tested in a temperature range from room temperature to 250 ℃ with a strain rate of 1.0×10-3 s-1. The results show that the variations in yield strength for Mg97Zn1Y2 magnesium alloy sheets hot rolled at 390 ℃ and 420 ℃ with temperature resemble each other due to their similar morphology of the chain-shaped strengthening phase. The yield strength maintains at a high level of 283 MPa before 200 ℃ and decreases significantly at 250 ℃. Despite of the fine lamellar structure of Mg97Zn1Y2 magnesium alloy sheet hot rolled at 450 ℃, its yield strength decreases linearly owing to occurrence of the coarse grain, and drops to 239 MPa at 250 ℃. The elongation for all hot rolled Mg97Zn1Y2 magnesium alloy sheets increases slightly with increasing testing temperature.