饮料瓶瓶盖注射模设计

在分析塑件结构特点基础上，详细阐述了模具结构设计，介绍了模具工作过程。并以图示的方式模拟了模具的脱模过程。     

Effect of coagulation temperature on structures and properties of poly(<Emphasis Type="Italic">p</Emphasis>-phenylene benzobisoxazole) (DHPBO) fibers during dry-jet wet-spinning process

The effect of coagulation temperature on the morphology, microstructures and mechanical properties of dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO) fibers was investigated during dry-jet wet-spinning process, in which the coagulation bath concentration and drawn ratio were kept as 10 wt% of PPA in water and 1.7, respectively. The structures and mechanical properties of the as-spun DHPBO fibers were characterized by FTIR, XRD, SEM, and single fiber tensile testing. The results indicated that in PPA/H₂O coagulation system, when the coagulation temperature was 25°C, highly crystallized DHPBO as-spun fibers possessing fine crystallites, circular and smooth morphology, and excellent mechanical properties could be achieved. Supported by the National Natural Science Foundation of China (Grant No. 50673017), Shanghai Leading Academic Discipline Project (Grant No. B603) and the Program of Introducing Taleuts of Discipline to University of People’s Republic of China (“111” Program) (Grant No. 111-2-04)     

Effect of coagulation temperature on structures and properties of poly(p-phenylene benzobisoxazole) (DHPBO) fibers during dry-jet wet-spinning process

The effect of coagulation temperature on the morphology, microstructures and mechanical properties of dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO) fibers was investigated during dry-jet wet- spinning process, in which the coagulation bath concentration and drawn ratio were kept as 10 wt% of PPA in water and 1.7, respectively. The structures and mechanical properties of the as-spun DHPBO fibers were characterized by FTIR, XRD, SEM, and single fiber tensile testing. The results indicated that in PPA/H2...     

Introduction of fluorin into PBO polymer chains: Toward higher thermal stability and lower dielectric constant

A series of novel fluorinated benzoxazole polymers (6FPBO's) with high thermal stability and low dielectric constant were synthesized by copolymerization of 1,3-diamino-4, 6-dihydroxybenzene dihy-drochloride (DAR), 1,4-benzenedicarboxylic acid (PTA) and various amount of 4'4- (hexafluoroisopro-pylidene) bis (benzoic acid) (BIS-B-AF) in the medium of polyphosphoric acid (PPA). 6FPBO fibers were then obtained via dry-jet wet-spinning technique and characterized by means of Fourier transform infrared (FTIR) spectra, thermogravimetric analysis (TGA), single fiber tensile testing machine and scanning electron microscopy (SEM). FTIR spectrum of 6FPBO fibers indicated that the fluorine groups had been incorporated into PBO molecular chains successfully. TGA curves revealed that 6FPBO fibers possessed high thermal stability just as pure PBO fibers. Moreover, dielectric constant spectrum of 6FPBO exhibited that the polymers had low dielectric constant, especially in the range of high- frequency.     

Research on theory and key technology of trusted computing platform security testing and evaluation

Trusted computing has become a new trend in the area of international information security, and the products of trusted computing platform begin to be used in application. Users will not use the products of information security, unless it goes through the testing and evaluation. Here we concentrate on the testing and evaluation problem of trusted computing platform, begin with constructing proper formalization model of trusted computing platform for testing, and establish a mathematical chain of trust model...     

Microstructural Evolution of P92 Steel During Long-Term Aging

The mechanical properties and microstructure evolution of P92 steel were investigated after aging up to 11,000 h at 923 K. Charpy impact and tensile tests were carried out to study the strength and ductility of aged P92 steel. In addition, microstructure evolution of the samples during long-term aging was investigated with X-ray diffraction, optical microscopy and scanning electron microscope (SEM). Then, statistical quantitative image analysis based on SEM images was used to evaluate the precipitation during long-term aging. The mechanical properties were found to be associated with the evolution of precipitation, especially the coarsening of Laves-phase. Results show that the ductility and strength of P92 steel decrease with the growth of Laves-phase during short-term aging (shorter than 1000 h). However, as the aging time further increasing, the ductility and strength of P92 steel decrease slowly with the coarsening of Laves-phase.     

石油含水率测量动态补偿模型研究

针对传统微波透射法测量石油含水率存在的测量误差大等问题,提出了一种基于神经网络的动态补偿方法,确定衰减和相移两个参量作为动态补偿模型的输入;针对传统BP算法具有收敛速度慢、容易陷入局部极小值等缺点,采用微粒群训练算法对神经网络动态补偿模型进行训练,可使微波透射石油含水率测量结果的补偿过程具有寻优全局性和精确性。实验结果表明,利用该技术对石油含水率测量结果进行校正是一种有效的方法,具有一定的应用价值。     

一种新型并联混合有源滤波器的研究

本文提出了一种新型并联混合型有源滤波器的拓扑，新型拓扑通并联谐 振抑制流过无源网络的基波无功电流，减小了有源滤波器承担的基波电流。同时在此拓扑基础上讨论了它的控制策略，在此控制策略下，有源滤波器不承担基波电矿井，且只承担很小的基波电流，因此有源滤波器的容量达到了最小，本文分析了并联谐振对无源网络阻抗的影响，并对此分析了控制策略在传统拓扑和新型拓扑下对有源滤波器容量的影响，最后通过仿真证明了结论的正确性。     

一种可调姿态的机床模块机械接口设计与分析

可重构机床通过其功能模块互换来实现零件族内各零件的加工转换,然而受机床结构布局和模块自重等影响,如何保证模块可互换条件下的机床整机性能与精度要求是可重构机床研究领域中的难题.提出一种可实现模块姿态微调整又能保证机床整机刚度的机械接口装置,该接口采用梳齿结合面及辅助支撑实现机床模块间的精准定位和刚性连接,通过锁紧螺栓对弹性胀紧球接口单元施加预紧变形实现模块姿态的微调整,由接口单元内钢球的不同布置协调预紧变形与接口联接刚度;建立了该机械接口的有限元模型,分析了不同结构尺寸和受力条件对机械结构接口刚度特性的影响规律,为该机械接口的进一步应用提供了理论依据.     

微胶囊化改性氢氧化镁及其在低密度聚乙烯中的阻燃性能研究

采用一步法合成了三聚氰胺树脂和脲醛树脂.分别对氢氧化镁阻燃剂进行微胶囊化改性,通过对其FT-IR、SEM、TEM、TG-DSC、XRD,以及添加至高聚物中后进行复合材料常规力学性能测试和极限氧指数(LOI)的测定,研究微胶囊化改性超细氢氧化镁的改性效果.结果表明,三聚氰胺树脂和脲醛树脂被成功包覆在氢氧化镁表面,并且改性后氢氧化镁热稳定性良好,粉体与聚合物基体之间的界面粘结性得到提高,与未改性氢氧化镁相比机械性能有较大提高,其极限氧指数较低密度聚乙烯有很大提升.其中,以反应温度70℃、包覆量15%的微胶囊化改性效果最好.