High-efficiency finishing process for metal mold by large-area electron beam irradiation

A new finishing process for metal molds by large-area electron beam (EB) irradiation is proposed in this study. In the large-area EB irradiation equipment used here, an EB with high-energy density is irradiated without focusing the beam, and so the EB with a maximum diameter of 60 mm can be used for melting or evaporating metal surface instantly. Experimental results show that the surface roughness decreases from 6 μmRz to less than 1 μmRz in just a few minutes under proper machining conditions. The corrosion resistance of metal mold surface also could be greatly improved by large-area EB irradiation. Furthermore, the surface roughness of tilting surface close to 90° could be well improved. Therefore, large-area EB irradiation method has a possibility to become a high-efficiency finishing process for metal molds.     

Visible Light Excitation Characteristics of Novel Infrared Up-conversion Materials

The Fluorescence excitation spectrum, emission spectrum and infrared up-conversion luminescence excitation spectrum are measured. The results of spectrum measurement show that the electron trapping materials CaS: Eu, Sm are of visible light excitation. The mechanism of visible light excitation is analyzed.     

Effect of dose rate and length of storage on the ESR signal strength in irradiated chicken bone

One hundred and twenty-five pairs of chicken drumsticks were randomly allocated to one of five dose rates: 5, 10, 15, 20 or 600 kGyh-. The highest dose rate was obtained using a linear accelerator whilst the remaining dose rates were provided using a ⁶⁰Co gamma source. Each batch of 25 pairs was further divided into groups five of which were stored at 4°C for 0, 7, 14, 21 or 28 days. ESR spectroscopy was used to measure the intensity of the radiation-induced signal. There was a quadratic relationship between ESR signal strength and dose rate, which although statistically significant is unlikely to be of practical importance. The magnitude of the ESR signal declined by about 20% over the first 14 days of storage at 4°C and thereafter the decrease was minimal.     

一种适用于有限长度混合相位未知脉冲的最小平方反褶积新方法

普通的最小平方反褶积只有在子波为最小相位脉冲和反射序列为白噪声的假设下才是成立的,而对于混合相位未知脉冲来说,这种最小平方反褶积就不再适用了。本文提出一种适合于有限长度混合相位未知脉冲的最小平方反褶积方法。运用此法只需预先估计一个混合相位子波的长度。合成数据的试验结果表明,该方法有较好的效果,且对预先估计出的子波长度不敏感。文中还证明混合相位未知脉冲最小平方反褶积等效于一种有间隙的平滑误差滤波器的作用,而这种有间隙的平滑误差滤波又可分解为一个前向多步预测误差滤波与一个后向多步预测误差滤波之和。可以预计这种新的反滤积方法将在地震数据处理中得到有效的应用。     

A novel technique to prepare LiNbO3 at low temperature

Fresh niobium hydroxide was first precipitated from NbF₅ solution using an aqueous ammonium hydroxide under basic conditions. Then a simple procedure of mixing lithium and niobium hydroxides together and heating at a low temperature (400 °C) produced pure ultrafine single phase LiNbO₃ (LN). In the literature, this is the lowest temperature so far reported on the formation of LN. The phase content and lattice parameters are determined by X-ray diffraction (XRD). The average particle size and morphology were studied by transmission electron microscopy (TEM).     

辐射剂量对环氧树脂电子束固化行为的影响

分析了电子束剂量对环氧树脂体系辐射固化行为的影响规律。研究结果表明，电子束辐射过程中，温度由树脂辐射体系表面向内部逐渐降低，随着辐射剂量提高，树脂体系温度上升，辐射表面与内部的温度梯度加大，高辐射剂量下的温度变化缓慢。树脂辐射固化层厚度以及在相同厚度的固化程度均随辐射剂量增加，但增幅逐渐变小，树脂辐射固化度沿固化深度会加速下降。     

Plastic deformation of bcc metal thin foils without dislocation

Heavy plastic deformation of fcc metal thin foils to fracture has been found recently to proceed without involving dislocations, and it results in the formation of high density of vacancy clusters. Thin foil specimens of bcc metals such as V and Mo were plastically deformed to fracture in in situ elongation experiments under an electron microscope. Morphology of thinning and fracture was found to be similar to fcc metals, and no dislocation was observed during heavy deformation. Electron diffraction analysis at the tip of a crack during deformation confirmed a large elastic deformation of up to 5%. Unlike in fcc metal thin foil specimens, point defect clusters were not observed near fractured tips. This difference is attributed to the difference in vacancy reaction, though the deformation in bcc metals without dislocation most likely does produce vacancies.     

填充等离子体波纹波导色散曲线计算软件的设计

从一种正弦波纹波导慢波结构的色散方程理论推导出发,设计了在不同结构参数、有无电子注以及填充不同等离子体浓度的情况下,计算其色散曲线的专用软件.该软件除了具有传统的数值计算功能外,提供了一个较为友好的图形用户界面.该界面直接显示该波纹波导的结构图,同时用户可以通过该界面很方便地修改各主要参数,比较不同情况下得到的色散曲线,以获得优化的参数选择.     

多丝正比室中电子的最大漂移时间

多丝正比室中电子的最大漂移时间是逃逸门电路中的一个重要参数。这个参数的选择将影响逃逸门工作方式的多丝正比室的整体性能。通过实验测量得到了多丝正比室中电子的最大漂移时间的实际值和最大漂移时间随多丝正比室工作状态的变化，测量结果在实际中得到应用。     

国际微电子专用关键设备的现状和发展趋势（考察报告）

讲述了参观Ｓｅｍｉｃｏｎ／ｗｅｓｔ９４′展览会及考察美国和西德的５个公司、１所大学所了解到的投影光刻技术、电子束曝光技术、透镜面形测试技术的发展。