型钢与混凝土之间粘结强度的力学分析

基于大量实腹式型钢混凝土试件粘结滑移性能对比试验研究结果,得到了型钢与混凝土粘结面上粘结应力的分布特征和粘结力组成部分(化学胶结力、摩擦阻力和机械咬合力)之间的转化规律;根据磨损接触面的运动调节机理,分析了型钢与混凝土之间粘结面的微动磨损特征,论证了型钢混凝土粘结滑移试验中荷载-滑移曲线与接触体系三体理论中破损混凝土形成和演化规律之间的吻合特性;根据型钢与混凝土协同受力的主要缺陷是其粘结面易发生剪切粘结破坏的试验结论,对型钢与混凝土之间的粘结滑移破坏进行了剥层理论分析,阐释了型钢与混凝土之间摩擦阻力和机械咬合力的产生和转化规律;对型钢混凝土粘结强度进行了塑性极限理论分析,推导了粘结强度上限解的数学表达式,并对影响型钢与混凝土粘结性能的材料因素进行了探讨。研究成果为型钢混凝土结构的设计计算理论研究奠定了基础,并且为组合结构的数值实验分析提供了理论依据。     

角膜移植手术中打结作业的力学建模与分析

根据拍摄的外科医生临床手术缝合影像,将手术打结动作分解为4个基本步骤.以此为依据,建立了结点形成的力学模型并将其简化为对称张紧的受力形式.根据临界滑动条件,缝线间摩擦力和点接触形式作用的张力,建立了结点运动的力平衡方程并求解出合理的拉力角度范围.在此基础上,进一步推导出了缝线末端的运动轨迹方程,并对其进行分析和仿真.通过对比不同拉力条件下的仿真结果,规划出角膜移植手术机器人打结机构末端的最佳运动路径.     

柱加大截面加固与碳纤维加固框架节点的试验研究与比较

进行了柱加大截面加固框架节点及碳纤维加固框架节点的试验,并对两者在承载力、刚度、延性及耗能能力等方面进行了比较。两种加固方法都改变了节点核芯区脆性破坏的性质,节点核芯区的极限强度、延性、刚度及耗能能力都得以提高。柱加大截面法加固还提高了原节点核芯区的开裂荷载。     

水力冲孔作用下煤层底抽巷围岩损伤机理及位置优化方法研究

底抽巷作为瓦斯抽采的辅助巷道,有时还要兼顾煤层回采期间的通风等作用,服务期间需经历2次掘进扰动和煤层采动等影响,因此底抽巷合理布置对瓦斯抽采效果、岩巷支护稳定性具有极其重要的作用。基于理论分析、现场工程类似、数值模拟等方法对梁北煤矿大埋深底抽巷布置方案展开研究。在综合考虑应力环境、瓦斯抽采与底板突水等综合因素的影响后,最终确定梁北煤矿21071底抽巷层位选择为沿L8灰岩进行掘进,割灰岩厚度1~1.5m,距煤层实际距离约21m。     

基于多特征融合的票据分类技术及应用

对票据进行高速、准确的分类是实现票据自动处理的关键。论文分析了各种票据分类方法的优缺点,并根据金融、税务等行业所使用的票据特点,提出基于多特征融合的快速分类方法,可以将票据的几何尺寸、分类条码、标题、特征字符串、特征图像块、特征框线等特征有机地融合并进行分类,提高了票据分类的速度与准确性。利用该技术设计的银行票据处理系统的实际应用说明了该方法的有效性。     

脱硫石膏热处理制备注浆成型模具

石灰石-石膏湿法烟气脱硫技术以石灰石为原料吸收烟气中的二氧化硫,得到石膏晶体。在控制二氧化硫排放的同时,脱硫石膏的处理与综合利用也非常重要。以脱硫石膏为原料,分析脱硫石膏的成分,通过热处理使其脱水,并表征热处理过程对石膏物理性能的影响。将热处理后的石膏用于石膏模具的制作,并最终制备固体氧化物燃料电池阳极支撑体。燃料电池测试的结果显示,脱硫石膏可以用于管式固体氧化物燃料电池的制备。     

Preparation and characterization of multilayer Gd2O2S:Tb phosphor screen for X-ray detection application

Gd2O2S:Tb (GOS) phosphor screen, generally with a multilayer structure, has been widely used in digital X-ray imaging. GOS phosphor screen is fabricated via a slip casting route, which is an effective method to obtain multilayer composites with good strength. The GOS slurry was prepared using the menhaden oil, polyvinyl butyral and PEG-400 as dispersant, binder and plasticizer, respectively, and slip casted on a support layer. After the GOS scintillation layer is formed, a transparent polyethylene terephthalate film is covered on it as a protective layer. The X-ray excited emission spectra of the obtained GOS phosphor screen is well match to the spectral response of a-Si:H photodiode, and the spatial resolution was close to 3.7 LP/mm, which could meet the request of the commercial application.     

Colloidal processing of Al2O3-doped zirconia ceramics with CaO–P2O5–SiO2 glass as additive

Well-dispersed concentrated aqueous suspensions of Al₂O₃-doped Y-TZP (AY-TZP), AY-TZP with 5.4 vol% of CaO–P₂O₅–SiO₂ (CaPSi) glass (AY-TZP5) and 10.5 vol% CaPSi glass (AY-TZP10), with ammonium polyacrylate (NH₄PA) dispersant were prepared to produce slip cast compacts. The rheological properties of 35 and 40 vol% slips were studied. The densification, microstructure as well as hardness and fracture toughness were investigated as a function of CaPSi glass content at 1300°C-1500°C. The optimum NH₄PA concentration of 35 vol% AY-TZP5 and AY-TZP10 slips at pH ~9 was found to be about 43% and 67% greater than that of AY-TZP slips; this behavior was related to the greater amounts of Ca²⁺ ions leached out from the CaPSi glass surface. The viscosity of stabilized 40 vol% slips with NH₄PA attained a minimum value at 5.4 vol% CaPSi glass addition, and resulted in a more dense packing of cast samples. AY-TZP5 can be sintered at a lower temperature (1300°C) compared to that of AY-TZP. AY-TZP5 exhibited a fine microstructure of tetragonal ZrO₂ (grain sizes below 0.3 µm), and ZrSiO₄–Ca₂P₂O₇ particles homogeneously distributed within the zirconia matrix. It presented similar fracture toughness and a slightly lower hardness compared to those of AY-TZP.     

Making reusable reaction-bonded silicon nitride crucibles for silicon casting from kerf-loss silicon waste

Silicon kerf loss during wafer slicing and the broken quartz crucibles after silicon casting are two major solid wastes from photovoltaic (PV) industry. Especially, the recycle of kerf-loss silicon has become an urgent issue because near 100 000 t of solid wastes are generated every year. One of the most meaningful recycle routes of the kerf-loss silicon is to make silicon nitride crucibles to replace the quartz crucibles. In this study, we demonstrated how this is feasible through acid leaching refining, slip casting, and nitridation. The reaction-bonded silicon nitride (RBSN) crucibles after oxidation were found pure enough for silicon ingot growth. More importantly, they could be reused after ingot growth. With the present examples, the potential of using the kerf-loss silicon for fine ceramics is prominent.