Feng XIAO
,
Liang FANG
材料科学技术（英）
Density of molten Ni and Ni-W alloys was measured in the temperature range of 1773~1873 K with a sessile drop method. The density of molten Ni and Ni-W alloys trends to decrease with increasing temperature. The density and molar volume of the alloys trend to increase with increasing W concentration in the alloys. The calculation result shows an ideal mixing of Ni-W alloys.
关键词:
Density
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null
,
null
,
null
Ying XU
,
Mingli LI
,
Yan GUO
,
Fengji LU
材料科学技术（英）
The nano-TiO2/unsaturated polyester resin (referred to as nano-TiO2/UPR hereafter) was prepared with the ``reaction method", by which a chemical bond generated between nano-TiO2 and UP was inserted in the UP long chain. The performance of the nano-TiO2/UPR was determined by such a new structure. The research results showed that the reactivity of nano-TiO2/UPR is higher than that of UPR. The impact strength and bending strength of nano-TiO2/UPR are greatly enhanced as compared with that of UPR. Thermal resistance and dielectric property of nano-TiO2/UPR are the same as that of UPR.
关键词:
Nano-TiO2
,
null
,
null
,
null
Qijie ZHAI
,
Li FU
,
Huaying ZHAI
材料科学技术（英）
Effect of Nb on microstructure and mechanical properties of chilled cast iron at room and elevated temperatures is studied in this research. The results demonstrate that the cast structure and mechanical properties of chilled cast iron at room and elevated temperatures are improved with the addition of trace amount of Nb. However, if Nb was added too much, the cast structure and mechanical properties of chilled cast iron would deteriorate. The suitable content of Nb in chilled cast iron is about 0.05% (mass fraction). Except the dissolution in the matrix of cast iron the excessive Nb will form Nb-rich phases in three morphologies. Those are lumpy NbC, complicated strip-like phase and compound with pearlite structure.
关键词:
Nb
,
null
,
null
,
null
Wen CHEN
,
Manzhu KE
,
Qing XU
,
Quanyao ZHU
,
Liqiang MAI
,
Li LI
材料科学技术（英）
In this article, the vanadium pentoxide sols are synthesized by two different routes (melted and quenched in oxygen atmosphere or in air). The structure and properties of the vanadium pentoxide xerogel films are characterized by XRD, ESR, cyclic voltammograms curves and UV-visible transmittance analysis. The results show that the sample prepared in oxygen has poorer crystallization, lower content of V4+ ions and higher Li+ insertion capacity compared with that prepared in air.
关键词:
Preparation atmosphere
,
null
,
null
,
null
Dongxin HE
,
Chengguo WANG
,
Yujun BAI
,
Bo ZHU
材料科学技术（英）
To find out the high-quality polyacrylonitrile (PAN) fibers, some differences are sought by comparing domestic PAN fibers with the foreign ones. X-ray diffractometer (XRD), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectrometer, elemental analyzer, tensile-testing machine and high-temperature differential scanning calorimeter (DSC) are used to characterize the individual microstructure, chemical structure, elemental content, mechanical properties and thermal properties. It is found that high-quality PAN fibers have high density, lower titre, higher or adequate tensile strength, and they also have better conglomeration structure, smaller crystal dimension with dispersive distribution, less microvoids and flaws.
关键词:
Polyacrylonitrile (PAN) fiber
,
聚丙烯腈纤维
,
碳纤维
刘彪
,
冀棉
,
杨士勇
宇航材料工艺
太阳帆飞船由于无需动力等优势近年来引起了各国科学家的研究兴趣,并在深空探测领域具有重要的应用前景.太阳帆的结构设计和材料选择是影响其性能的重要因素,本文结合太阳帆飞行环境的特点,介绍了太阳帆的基本结构和飞行原理,重点针对目前几种比较典型的太阳帆设计,对其支撑材料以及帆面薄膜材料进行了综述,并分析了各种材料和设计的性能特点.
关键词:
飞行器
,
太阳帆
,
结构
,
材料
吴文军
,
胡子君
,
李俊宁
,
杨海龙
,
王晓婷
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2014.01.020
在溶胶-凝胶过程中加入纳米Al2O3颗粒制备Al2O3掺杂的SiO2纳米透波/隔热材料,研究了Al2O3掺杂对材料高温热稳定性、介电性能及隔热性能的影响.结果表明,Al2O3掺杂阻碍了SiO2颗粒之间的烧结,提高了材料的使用温度;材料介电常数符合Lichtenecker对数法则;室温热导率略有提高,通过组合结构改善了材料的隔热性能.
关键词:
Al2O3
,
透波/隔热材料
,
结构
,
性能
沈锦玉
,
朱海霖
,
冯新星
,
陈建勇
功能材料
利用冷冻干燥法制备了β-CaSiO_3/丝素蛋白复合支架材料,经XRD和FTIR分析表明复合支架中丝素的结构主要以β-折叠为主;SEM分析显示材料孔隙分布均匀,孔连通性较好,孔径尺寸约为100～300μm.对支架的孔隙率和机械强度等性能进行了表征,研究表明复合支架的孔隙率为83%～87%,机械强度有较大提高.应用模拟体液浸泡实验研究了复合支架的体外生物活性,并用XRD、FESEM和EDS对试样表面进行了表征;结果显示,样品经模拟体液浸泡3天后,表面都能沉积出类骨羟基磷灰石(HA)层,β-CaSiO_3的加入能加快复合支架表面沉积类骨HA的速度.研究结果显示β-CaSiO_3/丝素蛋白复合支架材料有望作为强度较好的生物活性硬组织修复材料.
关键词:
丝素蛋白
,
β-CaSiO_3
,
复合支架
,
结构
,
生物活性
