注重Html型帮助制作的规范化及主题大纲的作用

高效地制作适用的Html型帮助，需要制作者掌握帮助的制作原则和规范制作过程．主题大纲的设计是帮助制作的核心，其它步骤以主题大纲为依据，在制作过程中要充分利用模板，从而能快速地制作出风格统一的帮助页面，     

任意变迹的窄带宽光纤布拉格光栅的制备(英文)

通过控制平台移动速度来控制紫外曝光量和2次曝光的方法实现任意变迹光纤布拉格光栅的制备.该方法采用连续氩离子激光作为紫外光源,不需要光强掩模板,通过对移动平台速度的编程控制可以获得任意的光栅结构参数,如长度、变迹包络、平均折射率改变量等.在2次曝光过程中,由于对2次紫外曝光量的精确控制,整个光栅的总平均折射率变化保持不变,从而避免了由此引起的啁啾而可以获得无旁瓣窄带宽的反射光栅.采用该方法制备了一根2 cm长的高斯变迹光栅,其反射带宽达到了0.15 nm,反射率约为95%.     

Splitting PMMA with Mini Cutting Explosives

In order to improve the present aviation ejection escape system, the application of explosion cutting technique to aviation escape system is proposed to weaken the strength of canopy before ejecting it. A series of mini cutting explosives are designed to investigate the process of splitting PMMA plate. The phenomenon of spallation in PMMA is observed. The effects of different parameters of mini cutting explosives on the cutting depth are obtained. Consequently the appropriate material of half-circular metal covers, explosive types and the ranges of charge quantities are determined. On the other hand, the cutting process of aviation PMMA plate by mini cutting explosives is simulated by means of nonlinear dynamic analysis code LS-DYNA. In finite element analysis,Arbitrary Lagrangian Euler (ALE) algorithm is used to depict the fluid property of high energy explosives. Continuous damage material model is used to simulate the complicate dynamic damage behavior of PMMA due to explosion shock waves. Only sliding contact option is defined to fulfill the fluid-structure interaction between explosives and PMMA plate by distributed parameter methods. Phenomenon of spallation observed in the experiment is presented in the simulation. The relationship between the penetration depth of PMMA plate and charge linear density obtained by numerical simulation agrees well with experimental result.     

基于选择性激光烧结的骨组织仿生支架

This paper introduces a technical method by which bone tissue bionic scaffolds are fabricated on a selective laser sintering machine. It also analyses determinative factors in fabricating porous structure using this method, and proposes a new technique to fabricate porous structure by rapid prototyping method.     

“射频电路与天线”创新性实验

提出"射频电路与天线"课程的一种创新实验。实验内容是让学生全程自己动手设计和制作射频前端系统中的关键器件,均用铜贴纸贴在单面覆铜的FR4板上方法实现。通过实验,学生不仅能掌握电磁仿真软件的使用,同时还掌握射频器件的设计思想。创新实验能够有效地培养学生的独立研究能力、创新能力和综合设计能力,提高学生的工程素养和科研素质。     

Influence of Poly(methylmethacrylate) Dopant on Butadiene Derivative Electroluminescence

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Martlab在曲面建模中的应用

在准分子激光手术治疗中,手术的精确性和模型的准确性描述是重点同时也是难点,它直接决定手术的效果。针对单纯性近视情况,提出了一种新的理论模型,给出了其数学表达式,并在准分子激光治疗机上进行PMMA板试验,取得了很好的效果。     

光的衍射法测量杨氏模量

拉伸法测量金属丝杨氏模量的关键是如何测准金属丝在拉力作用下的微小伸长量．利用光的衍射法可以较精确地测量长度变化这一特点,对钢丝的杨氏模量进行了测量,给出测量杨氏模量的一种新方法．     

Constructing Rotating Item Pools for Constrained Adaptive Testing

Preventing items in adaptive testing from being over- or underexposed is one of the main problems in computerized adaptive testing. Though the problem of overexposed items can be solved using a probabilistic item-exposure control method, such methods are unable to deal with the problem of underexposed items. Using a system of rotating item pools, on the other hand, is a method that potentially solves both problems. In this method, a master pool is divided into (possibly overlapping) smaller item pools, which are required to have similar distributions of content and statistical attributes. These pools are rotated among the testing sites to realize desirable exposure rates for the items. A test assembly model, motivated by Gulliksen's matched random subtests method, was explored to help solve the problem of dividing a master pool into a set of smaller pools. Different methods to solve the model are proposed. An item pool from the Law School Admission Test was used to evaluate the performances of computerized adaptive tests from systems of rotating item pools constructed using these methods.     

基于CAM模型的沥青混合料粘弹性能研究

为了在全频范围内研究沥青混合料的粘弹特性,采用动态剪切流变仪对沥青混合料进行连续动态频率扫描,得到温度-频率-动态模量的三维关系．利用时温等效原理,将频率扫描试验得到的三维关系进行温-频转换,获得了跨越15个数量级的动态模量随频率变化的二维全频主曲线．基于试验所得到的全频主曲线,利用CAM流变模型对几种沥青混合料的流变性能进行了比较分析．结果表明,动态流变试验是获得沥青混合料全温全频主曲线的有效方法,基于全频域的CAM模型能够很好地描述沥青混合料的粘弹变形特性．     

Heat exchanging process of metal target under millisecond pulsed laser shocking

Laser plays an important role in synthesizing nanometer material. A three-dimensional mathematical model is established in this paper when single pulsed millisecond laser shocks the surface of the metal target at a liquid-solid interface. By changing laser power density and target size, the temperature field variation of the metal target is investigated. Results show that the generation process of nanoparticles includes heating, melting and boiloff.     

物理实验中有趣的几个“三”

对初、高中阶段的物理实验进行系统总结,从实验的基本组成、测量仪器的构成以及自动控制装置的构成三个方面进行了分析,发现都与"三"有密切联系。掌握了物理实验的基本组成就可以根据需要灵活设计探究实验;掌握了测量仪器的基本构成就可以根据需要自行设计、制作实验器材;掌握了自动控制装置的基本构成就可以设计、组装自动控制装置。通过对物理实验规律的归纳总结引导读者反思实验教学中对科学方法教育的创新和钻研。     

Preparation of poly (methyl methacrylate)/nanometer calcium carbonate composite by in-situ emulsion polymerization

Methyl methacrylate (MMA) emulsion polymerization in the presence of nanometer calcium carbonate (nano-CaCO3) surface modified with (-methacryloxypropyltrimethoxysilane (MPTMS) was carried out to prepare poly (methyl methacrylate) (PMMA)/nano-CaCO3 composite. The reaction between nano-CaCO3 and MPTMS, and the grafting of PMMA onto nano-CaCO3 were confirmed by infrared spectrum. The grafting ratio and grafting efficiency of PMMA on nano-CaCO3 modified with MPTMS were much higher than that on nano-CaCO3 modified with stearic acid. The grafting ratio of PMMA increased as the weight ratio between MMA and nano-CaCO3 increased, while the grafting efficiency of PMMA decreased. Transmission electron micrograph showed that nano-CaCO3 covered with PMMA was formed by in-situ emulsion polymerization.     

培养运算能力的方法

运算能力与其它能力密切相关，培养运算能力必须有层次地进行：正确理解概念，定理的条件和结论，清楚特定运算方法的适用范围，让学生明白进行某种运算的道德；运算必须有理有据；加强运算的基本功训练，积累经验，减少失损，提高运算速度，掌握运算方法，学会一些运算技巧，提高运算质量。     

Correlation Between Process Parameter and Primary Dendrite Arm Spacing in Laser Welding of Cu and Al

A combined numerical model of thermal field and the primary dendrite arm spacing(PDAS) was proposed to correlate the process parameters and PDAS in laser welding of Cu and Al. The solidification parameters simulated by the finite volume method with commercial software ANASYS FLUENT were applied in the PDAS model to predict the dendrite arm spacing of fusion zone. Dendrite was also examined by the metallographic method to validate the model. Results indicate that the calculated PDAS agrees with metallographic measurements reasonably, especially the Hunt model. PDAS increases apparently with increasing laser power while decreases slightly with increasing welding speed. Increasing laser power increases the secondary dendrite and increasing welding speed increases the microporosity in dendrite.     

选择性激光烧结零件的后处理

用激光快速成型设备间接烧结金属粉末,由于受设备激光功率的限制,制造出零件的密度和强度都很低,为改善这种情况,文章进行了一系列的试验.试验结果表明:在普通的粉末冶金烧结炉内,原型件通过两次烧结——熔渗铜后序处理即可获得高的强度、密度,可直接用作放电加工工具的电极.该方法为金属零件与电加工电极的快速制造开辟了新途径.     

用半导体激光器测定金属的线胀系数

本文介绍了用半导体激光器测定金属的线胀系数的方法,并给出测量结果。通过实验对比,此方法完全可以代替传统的测量金属线胀系数方法。在实验误差允许的范围内,完全满足实验精度的要求。     

锂电池负极α-Fe2O3纳米粒子制备及电化学性能研究

以高分子微球聚苯乙烯（PST）和聚甲基丙烯酸甲酯（PMMA）作为组装体,采用自组装方法在PST和PMMA微球表面自组装制备纳米α-Fe2O3电池负极材料,组装温度为PST（T=70℃）和PMMA（T=60℃）聚合温度.结果显示,采用PST作为组装体获得的α-Fe2O3纳米粒子颗粒更细,约70nm,粒径更均匀,分散性更好;而PMMA组装体获得的纳米粒径约80nm,分散性相对较差,主要原因是PMMA微球质地较软,易发生变形,而使α-Fe2O3纳米粒子吸附在PMMA表面不均匀,在热处理过程中受热不均导致α-Fe2O3纳米粒子尺寸不均,且有团聚趋势.XRD显示,两种组装体获得的均为纯相α-Fe2O3结构.电化学性能显示,采用PST作为组装体制备的纳米α-Fe2O3作为电池负极电化学性能明显优于PMMA组装体.     

周期可调光栅的制备

利用模板技术复制光盘沟槽结构,制备了聚二甲基硅氧烷(PDMS)弹性光栅薄膜。将复制具有光盘沟槽负结构的弹性光栅薄膜在自制的弹性光栅支架上进行拉伸,使光栅常数发生了连续变化,达到周期可调的目的。采用激光光栅衍射方法测量了光栅常数,并用扫描电子显微镜和光学显微镜分别对光栅薄膜微结构进行了表征。结果表明,制备的PDMS弹性薄膜光栅衍射现象显著,对此弹性光栅薄膜进行拉伸,光栅常数可连续调制,且光栅条纹无可视畸变。用该方法复制的周期可调光栅具有工艺简单、成本低廉等优点。相对于传统光栅,PDMS光栅材料环保无毒,具有高透光率、耐热性、耐寒性等优良的物理特性,特别是光栅常数连续可调,可以实现光路的切换和光通信信号滤波等多种功能,有广泛的应用前景。     

40Mn18Cr4V无磁钢激光焊接头组织和硬度分析

对40Mn18Cr4V无磁钢进行了三种不同工艺的激光对接焊,分析不同焊接工艺条件下激光焊接头的金相组织和显微硬度。结果表明焊缝金属中有大量δ铁素体形成,焊缝和热影响区的显微硬度较母材均降低,说明该钢种不适合于激光对接焊,只有使用激光填丝复合焊才有可能满足40Mn18Cr4V钢的焊接技术要求,同时所使用的焊丝成分也不能与母材成分完全相同。