高支化含无机粒子的巯基硅氧烷溶胶的制备及结构表征

用溶胶-凝胶法制备了一种新型的多功能巯基硅氧烷溶胶,其结构用1H-NM R,FT-IR和M S进行了表征,巯基硅氧烷溶胶的无机粒子粒径大小与分布用小角度光散射仪(SALS)进行了测定。这种新型巯基硅氧烷溶胶能够提高改性亚麻籽油体系自由基聚合速率。     

聚甲基丙烯酸酯类玻璃化温度的量子化学-神经网络方法研究

用密度泛函(DFT)方法在6-31G(d)基组优化了32种聚甲基丙烯酸酯类的结构单元,得到了其量子化学参数,用模式识别,逐步回归和人工神经网络方法探讨了这些参数与聚甲基丙烯酸酯类Tg的关系,模式识别两类Tg大小不同的聚合物基本分布在不同区域,用逐步回归和人工神经网络方法所建立的定量模型的计算值与实验值的相关系数分别为0.9760,0.9912,预报结果与实验值基本一致。     

尘埃粒子计数器测量颗粒粒径大小及其分布准确性的检定装置及其不确定度分析

本文介绍了检定尘埃粒子计数器测量颗粒粒径大小及其分布准确性用的装置,并对其进行了不确定度分析.     

基底结构对纳米铜膜光电性能影响

采用射频磁控溅射法,在涤纶机织布、纺粘非织造布、针织布、纤维膜表面沉积纳米铜薄膜,并用紫外-可见分光光度计与四探针测试仪测试样品透光和导电性能,用彩色摄像机观察溅射样品的表面形貌,用毛管流动孔隙仪测试不同基底孔隙大小及分布,并对结果进行比较分析。结果表明,基底布表面结构形貌与孔隙大小对样品光透射率、导电性能均产生影响。随基底布孔隙率的增加,样品透射率提高,导电性能减弱,针织布由于其松散的线圈结构使得其表面电阻难以测知。     

使用材料复合法制取多孔电极及其电化学性能的测试分析

用材料复合的方法制出了多孔锌电极, 给出了可充分反映其内部三维网络骨架结构的扫描照片, 定量测试并分析了其孔隙率的大小, 进行了模拟放电, 测得电极的极化曲线和恒流下的放电曲线, 并和目前电源行业经常采用的用一般方法制出的多孔电极进行了性能比较分析。     

尘埃粒子计数器测量颗粒粒径大小及其分布准确性的检定装置及其不确？…

本文介绍了检定尘埃粒子计数器测量颗粒粒径大小及其分布准确性用的装置，并对其进行了不确定度分析。     

办公室空调房间不同送风速度的数值模拟

气流组织是控制、安排空调区域内空气流动过程的技术,其优劣直接影响室内的空调效果,而室内气流组织与送风温度的大小有直接关系。以办公室空调房间为例,建立其数学和物理模型,用CFD软件Airpak模拟它在不同的送风温度下的室内温度场和速度场,得出送风温度与室内温度场和速度场的关系,并用能量利用系数指标对其设计效果进行评价。结果表明送风温度升高时,室内气流流形和各点速度大小几乎不变,相同位置的气流温度有所升高,但垂直方向上温度梯度变小。     

办公室空调房间不同送风温度的数值模拟

气流组织是控制、安排空调区域内空气流动过程的技术,其优劣直接影响室内的空调效果,而室内气流组织与送风温度的大小有直接关系。以办公室空调房间为例,建立其数学和物理模型,用CFD软件Airpak模拟它在不同的送风温度下的室内温度场和速度场,得出送风温度与室内温度场和速度场的关系,并用能量利用系数指标对其设计效果进行评价。结果表明送风温度升高时,室内气流流形和各点速度大小几乎不变,相同位置的气流温度有所升高,但垂直方向上温度梯度变小。     

JVC推出家用简易高清晰度W—VHS新格式录像机

最近,JVC推出家庭用的简易高清晰度W—VHS新格式录像机,其最大特点是与现行VHS、S—VHS在高端兼容,实现了现在家庭中以等身高大小录/放画质优异的高清晰度MUSE节目,W—VHS格式技术内容如下:     

CLVD法制备炭毡/炭复合材料

用化学液气相沉积(CLVD)法制务炭毡／炭复合材料，用电镜扫描（SEM）观察了材料的微观结构，并分析了预制件内部温度梯度的建立过程，结果表明：该法制备的炭毡／炭复合材料致密均匀、结构理想，其预制体内部温度梯度的大小与前驱体的沸点有关。     

一种测定晶体取向及其分布的简便XRD方法

提出了旋转定向测试法，其原理是使试样的在粉末X射线衍射仪上进行θ扫描的同时绕其端面法线自转，增加了晶面法线通过衍射平面的机会。通过这种方法可直观地区分取向多晶，准单晶或者单晶体，评定研制过程中准单晶和择优取向材料的晶体品质，确定单晶，准单晶及择优取向等材料的晶面相对宏观端面的晶向偏离角和取向分散度，还可对单晶体材料进行三维晶面定向。旋转定向法测试晶体取向具有快速简便，一机多用，精度高等优点，在电子、光学、磁性，机械等材料研究领域具在广泛的应用。     

受控单晶晶种制取方法──单晶铸件定向凝固工艺研究之一EI

探讨了制造单晶铸件所需基本条件之一──制取具有良好性能和晶体取向晶种的即受控晶种的方法。主要对螺旋选晶法受控晶种的制取作了具体阐述。     

利用菊池衍射花样鉴定晶体结构的方法研究

电子背散射衍射(Electron Backscatter Diffraction, EBSD)是研究材料显微结构的重要手段之一, 通过EBSD获取的菊池衍射花样是材料内部微观晶体结构的直观反映。本研究通过识别菊池花样中的对称轴, 结合晶体对称定律, 提出了一种利用菊池花样进行晶体对称性分析和晶体结构鉴定的方法。通过该方法成功对三个未知样品的对称性和晶体结构进行了判断。其中一个样品确定到所属晶系, 另两个样品锁定到部分点群, 通过确定晶系和点群排除了部分不符合对称性的相鉴定结果。研究结果表明, 利用菊池花样进行对称性分析是判断晶体结构的有效方法。同现有方法相比, 菊池衍射花样法大大缩小了相鉴定的检索范围, 显著提高了相鉴定的准确性和可靠性, 是一种有望用于新一代EBSD设备的标定技术。     

A novel microcomputer temperature-compensating method for an overtone crystal oscillator

In this paper, a novel microcomputer temperature-compensating method for an overtone crystal oscillator (MCOXO) is presented. In this method, a ceramic oscillator is chosen, and its output frequency is mixed with the output frequency of an overtone crystal oscillator. A crystal filter is used to suppress the spurious mixing products. A microcomputer is used to control the switch capacitance array that is connected to the ceramic oscillator circuit. The frequency deviation of the crystal oscillator is directly compensated by the output frequency of the ceramic oscillator. As a result, the method is able to overcome the disadvantages of frequency stability degradation and phase noise deterioration that are provoked by adding inductance or frequency multiplication in traditional compensating approaches. At the same time, this method is able to compensate a quite wide frequency range and many types of oscillators, not just crystal oscillators. The experimental compensating results show that, using this method, the frequency-temperature stability of a 100 MHz 5th overtone temperature-compensated crystal oscillator can achieve /spl les/ /spl plusmn/2/spl times/10/sup -6/ for 0-70/spl deg/C.     

Growth of TGS single crystal by conventional and SR method and its analysis on the basis of mechanical, thermal, optical and etching studies

Unidirectional <001> bulk ferroelectric Tri glycine sulphate (TGS) single crystal of diameter 18 mm and length 150 mm was successfully grown by SR method. The grown TGS single crystal was characterized using etching, Vicker's microhardness, TG-DTA and UV-Vis analysis. The TGS crystals grown by SR method have higher hardness than conventional method grown crystals. Dislocation density (DD) is less in SR grown crystal compared to conventional method grown TGS crystals. The transmittance of SR grown TGS is 8% higher than that of the conventional grown crystal.     

聚焦离子束加工单晶体金刚石刀具实验研究

作为超精密切削加工刀具的理想材料,单晶体金刚石材料的加工制造方法直接决定了刀具切削加工表面的精度和质量.由于金刚石材料具有明显的各向异性,在传统的金刚石刀具机械刃磨法中需要综合考虑制备工艺和刀具性能的协同关系,主要包括不同晶面表现出显著的物理机械性能差异、不同晶向存在显著的难磨和易磨方向等.本文针对聚焦离子束(FIB)技术加工金刚石刀具的过程中,金刚石材料性质对聚焦离子束加工质量、加工效率的影响规律等关键工艺开展了研究.研究发现,与传统的机械刃磨法相比,聚焦离子束加工是基于高能离子束的轰击溅射实现材料的去除,聚焦离子束加工中存在的级联碰撞现象显著弱化了金刚石材料各向异性的影响.     

Fabrication of photonic crystals on several kinds of semiconductor materials by using focused-ion beam method

In this paper, we introduced the fabrication of photonic crystals on several kinds of semiconductor materials by using focused-ion beam machine, it shows that the method of focused-ion beam can fabricate two-dimensional photonic crystal and photonic crystal device efficiently, and the quality of the fabricated photonic crystal is high. Using the focused-ion beam method, we fabricate photonic crystal wavelength division multiplexer, and its characteristics are analyzed.     

Investigation of SR method grown 0 0 1 directed KDP single crystal and its characterization by high-resolution X-ray diffractometry (HRXRD), laser damage threshold, dielectric, thermal analysis, optical and hardness studies

0 0 1 directed potassium dihydrogen orthophosphate (KDP) single crystal was grown by Sankaranarayanan–Ramasamy (SR) method. The 0 0 1 oriented seed crystals were mounted at the bottom of the platform and the size of the crystals were 10 mm diameter, 110 mm height. Two different growths were tried, in one the crystal diameter was the ampoule's inner diameter and in the other the crystal thickness was less than the ampoule diameter. In the first case only the top four pyramidal faces were existing whereas in the second case the top four pyramidal faces and four prismatic faces were existing through out the growth. The crystals were grown using same stoichiometric solution. The results of the two growths are discussed in this paper. The grown crystals were characterized by high-resolution X-ray diffractometry (HRXRD), laser damage threshold, dielectric, thermal analysis, UV–vis spectroscopy and microhardness studies. The HRXRD analysis indicates that the crystalline perfection is excellent without having any very low angle internal structural grain boundaries. Laser damage threshold value has been determined using Nd:glass laser operating at 1054 nm. The damage threshold for the KDP crystal is greater than 4.55 GW cm⁻². The dielectric constant was higher and the dielectric loss was less in SR method grown crystal as against conventional method grown crystal. In thermal analysis, the starting of decomposition nature is similar in SR method grown KDP crystal and conventional method grown crystal. The SR method grown KDP has higher transmittance and higher hardness value compared to conventional method grown crystals.     

Full-field retardation measurement of a liquid crystal cell with a phase shift polariscope

A novel method is developed to provide high-resolution, full-field retardation measurement of the liquid crystal cell using a phase shift polariscope. The phase retardation of a liquid crystal cell is influenced by its thickness, and hence an accurate measurement of the full field retardation gives the thickness distribution of the liquid crystal cell. In the phase shift polariscope, phase shift images obtained by rotating the analyzer are recorded and analyzed to obtain the phase retardation and hence the whole field thickness distribution of the liquid crystal cells. The results obtained using this method are compared with those using a commercial pointwise sensor with good agreement. The proposed method yields accurate and repeatable full-field cell gap measurement of the liquid crystal cell with a simple experimental setup.     

喷流转晶法KDP晶体生长系统的流动与传质模拟

提出了一种通过锥顶喷流改善KDP锥面过饱和度的晶体生长方法。采用有限体积法和滑移网格技术,对传统转晶法及喷流转晶法的KDP晶体生长过程进行了数值模拟。展示了两种生长方式下晶体表面过饱和度时均分布云图及均方差,分析了不同转速、不同喷流速度、不同晶体尺寸对晶面时均过饱和度及均方差的影响。结果表明:相比于传统转晶法,喷流转晶法晶体的锥面过饱和度提高且表面均匀性增加。提高喷流速度可以进一步提高锥面过饱和度,但其均方差却呈现先减小后增大的变化。旋转速度的增加能提高锥面过饱和度并减小其均方差。此外,晶体尺寸也会在一定程度上影响喷流的效果。