聚四氟乙烯、聚醚醚酮和热固性树脂材料的摩擦磨损性能及差异性研究

选取了聚四氟乙烯(PTFE)、聚醚醚酮(PEEK)和热固性树脂3种常用于制备水润滑轴承的材料,测试了它们在不同载荷、不同转速和不同润滑状况下的摩擦磨损性能.研究结果表明,同种材料在不同润滑状况下的摩擦系数波动幅度有明显差别.在转速逐渐升高的条件下,热固性树脂材料和聚四氟乙烯材料的摩擦性能有一定提高,而聚醚醚酮材料的摩擦性能变化不大.PTFE材料在干摩擦状态下的磨损方式主要为粘着磨损和疲劳磨损,而在水润滑状态下的疲劳磨损程度加剧.     

溶胶-凝胶法制备耐高温绝缘涂料

以正硅酸乙酯、无机盐为先驱体,通过溶胶-凝胶法制备了耐高温绝缘涂料,并在该材料中加入了Cr2O3,经过800℃热处理后对该材料的电绝缘性能进行了测定并且利用DTA、XRD、SEM等测试手段对该材料的物相组成、表面形貌进行了研究与分析。结果表明,该绝缘涂料经800℃热处理后,电绝缘性能有了显著提高,绝缘电阻率可以达到57.71×109Ω.cm。     

溶胶-凝胶法制备耐高温绝缘涂料

以正硅酸乙酯、无机盐为先驱体,通过溶胶-凝胶法制备了耐高温绝缘涂料,并在该材料中加入了Cr2O3,经过800℃热处理后对该材料的电绝缘性能进行了测定并且利用DTA、XRD、SEM等测试手段对该材料的物相组成、表面形貌进行了研究与分析。结果表明,该绝缘涂料经800℃热处理后,电绝缘性能有了显著提高,绝缘电阻率可以达到57．71×10^9Ω·cm。     

外墙建筑涂料饰面做法十忌

外墙建筑涂料饰面具有造价较低、施工方便、提高工效、色彩丰富和便于维修更新等特点．多年来在各类建筑中得到广泛应用，但也经常发生颜色不匀、掉色、粉化、剥落等问题，严重影响建筑物美观．分析了外墙建筑涂料饰面做法十忌，供建筑施工参考．     

A combined continuous-discontinuous approach for failure process of quasi-brittle materials

Rock,concrete and other geo-materials,due to the presence of microstructural inhomogeneity,their fracture processes and damage characteristics are associated with the distribution of micro-cracks contained in the materials.In this study,by introducing a cohesive zone model based on fracture mechanics into the framework of deformable discrete element method,a continuous-discontinuous coupling analysis approach for simulating the fracture of quasi-brittle materials is proposed.The cohesive interface elements are inserted into certain engineering or research region.It is assumed that damage and fracture occur only in the interface elements,while bulk material is modeled to be elastic.The Mohr-Coulomb criterion with tension cut-off is adopted as the damage initiation criterion,and a scalar damage variable representing damage in the material is used to describe the rate at which the material stiffness is degraded.Cracks are simulated explicitly by the failure of the interface elements.Numerical simulations are performed in order to validate the suggested method.Partial applications are also listed.The results show that this method provides a simple but effective tool for the simulation of crack initiation and propagation,and it can reflect the whole process of quasi-brittle materials from small deformation to large deformation and failure.     

粉煤灰聚苯乙烯新型保温建筑材料的实验研究

为了有效利用粉煤灰和废弃聚苯乙烯研制新型节能墙体建筑材料,以石灰、石膏作为粉煤灰活性激发剂,用废弃聚苯乙烯颗粒(EPS)作为保温成分制备砌块材料,采用X射线衍射(XRD),热重-差热分析(TGA-DTA)和扫描电子显微镜(SEM)分析方法,研究了砌块材料的优化配比及分析了砌块材料的龄期水化机理.结果表明:石灰掺比为10％,石膏掺比为5％,粉煤灰掺量为20％～25％,改性EPS为2.5％时,砌块材料的导热系数为0.505 W/(m· K),保温性、施工性能、耐久与耐候性能均优良.     

夏热冬冷地区居住建筑外墙外保温的质量分析

为了减少质量缺陷或通病对外保温系统的影响,提高居住建筑外墙外保温系统的节能效果和使用寿命,结合外墙外保温的设计和施工要求,分析了外墙外保温工程的质量缺陷及产生的原因,提出了提高外墙保温系统耐久性的方法,通过案例研究了集成一体化保温板的生产和施工方法,为夏热冬冷地区居住建筑外墙外保温工程的设计与施工提供借鉴.     

地板采暖分户热计量系统的研究

分析探讨了住宅地板供暖系统采用按户计量的技术特点,提供地板采暖分户热计量时安装热计量装置的选择方法,并进行了不同工况下的的实验验证和与其它测试手段结果的比较.     

Preparation of Biologically Active Materials by Biomimetic Process

In order to form the apatite nuclei on a surface of the substrate, the substrate was placed on or in CaO, SiO2-based glass particles which were soaked in a simulated body fluid with ion concentrations nearly e-qual to those of human blood plasma, and to make the apatite nuclei grow on the substrate in situ, the substrate was soaked in another solution highly supersaturated with respect to the apatite. The induction period for the ap-atite nucleation varied from 0 to 4 days depending on the kind of the substrate.The thickness of the apatite layer increases linearly with increasing soaking time in the second solution. The rate of grouth of the apatite layer in-creases with increasing degree of the supersaturation and temperature of the second solution, reaching 7 um/d in a solution with ion concentrations which is as 1.5 times as those of the simulated body fluid at 60℃.The adhesive strength of the apatite layer to the substrate varies depending on the kind and roughness of the substrate. Polyethyleneterephthalate and polyethersulfone plates abraded with No. 400 diamond paste show adhesive strengths of as high as 4 MPa. This type of composite of the bone-like apatite with metals, ceramics and organic polymers might be useful not only as highly bioactive hard tissue-repairing materials with analogous mechanical properties to those of the hard tissues, but also as highly biocompatible soft tissue-repairing materials with ductility.     

汽车动力电池正极材料锰酸锂球磨工艺研究

通过锂电池正极材料锰酸锂的研究,探索材料制备工艺对正极材料电化学性能的影响,对比不同球磨工艺对所制备锰酸锂电化学性能影响,并使用XRD、粒度分析仪、高精度电池性能测试系统等对正极材料、电池进行分析,得出了的球磨方法.     

基于层次分析法的生土建筑综合效益评价

房屋建筑的综合效益是房屋从建造过程、运营使用和维护一直到回收循环再利用的全过程的效益.目前对生土建筑的综合效益评价尚未形成一个评价体系.本文从生土建筑本身的具体特点人手,从技术安全性、成本、环境及社会效益等多方面进行分析.将定性与定量的方法相结合,利用层次分析法确定各评价指标及其权重,建立生土建筑综合效益简易评价模型,为生土建筑提供一种科学的评价效益的方法.其基本评价步骤为首先构建生土建筑综合评价模型及判断矩阵,然后进行层次排序,并对判断矩阵进行一致性检验,在定性、定量指标转换的基础上形成评价方法.     

高层建筑现浇混凝土外墙外保温技术研究

介绍了新开发的外墙外保温节能体系;发现了植筋与钢筋网、钢板网连接的牢固性及钢板网抹灰技术能消除温度变化引起的应力变形和裂缝;提出并应用了外墙外保温分层卸荷理论,有效地解决了外墙外保温体系四大关键技术难题;阐述了工程应用情况,说明该新型外墙外保温节能体系施工安全、操作简便、经济实用、就地取材、高效节能,经实测建筑节能率达到了65%;适用于各类营房工程、边防哨所、永久性工事及各类工业与民用建筑外围护结构的墙体保温节能.     

A comparative analysis of dielectric properties of oil-paper insulation and polymer materials before and after thermal aging

The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric constants between insulation paper and transformer oil,restricted the development of transformer with smaller size and larger capacity.In view of this situation and the transformer’s demand for the dielectric physicochemical and mechanical property of insulation material,polycarbonate,polyester film and polyphenylene sulfide with high high-temperature resistance were chosen for the comparison analysis in this paper We did the 300-day thermal aging experiment on four samples in transformer oil under different aging temperatures of90°C,110°C and 130°C,then analyzed the changes of their dielectric properties.The experiment results are as follows;the permittivity and dielectric dissipation factor of the three polymer materials are apparently smaller than those of the paper both before and after 300-day aging;the volume resistivity and partial discharge inception voltage of the three materials are higher than those of the paper both before and after aging;and the breakdown field strength of polycarbonate is higher than that of the paper both before and after aging,while that of polyester film and polyphenylene sulfide are slightly lower than that of the paper.     

居住建筑的生态技术

住宅建设随着城市化进程的加快必然造成消耗资源、影响环境的局面,运用生态建筑技术建造住宅是改善这一局面的有效措施.从生态技术角度对住宅建筑的环境、节能、材料使用、绿化、使用太阳能和减少污染等方面进行了有益的探索.     

冬作训服系统层次搭配设计和保暖新材料应用研究

本文对YG606型平板保温仪增设了不同风速下多层次织物系统传热系数测试功能,研究了聚四氟乙烯微孔膜层压织物、陶瓷微粒填充聚丙烯纤维针织布等保暖新材料在军用冬作训服系统中的层次搭配方式.     

Possibility of utilizing water-atomized Fe-Ni-Mo steel powder as base materials for warm compaction process

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基于模糊层次分析法的公共建筑综合效益评价研究

针对公共建筑效益评价研究现状,提出对于公共建筑的评价更应当注重包括经济、社会、环境效益的综合效益评价．为此,应用模糊综合评判方法构建了公共建筑综合效益评价模型,并以徐州市奥体中心项目为例进行了实证研究．研究表明：将模糊综合评判方法应用于公共建筑综合效益评价,其评价结果真实可靠,具有较强的实用性和良好的应用价值．     

合肥地区典型外保温系统保温层最优厚度研究

对合肥地区某建筑进行模拟建筑能耗分析,得到外墙保温层厚度与相对节能量呈对数关系。通过运用生命周期成本法建立合肥地区典型外保温系统的计算模型,得出合肥地区PU泡沫塑料外保温系统、EPS外保温系统和胶粉聚苯颗粒外保温系统的保温层最优厚度。无机保温砂浆外保温系统不适宜本地区。     

集中供暖系统中使用地板辐射供暖的技术措施及常见问题浅析

针对集中供暖系统中使用地板辐射供暖出现的个别突出问题进行研究,分析其具体原因,指出集中供暖热水不宜直接作为地板辐射供暖的热源,并就地板辐射供暖中的常见问题,从设计、选材、施工和管理使用等方面提出具体要求和改进措施．