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941.
THE ELECTRON-BEAM IRRADIATION ON THE HIGH TEMPERATURE SUPERCONDUCTING THIN FILMS: A NUMERICAL SIMULATION OF THE LOW TEMPERATURE SCANNING ELECTRON MICROSCOPY
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Low-temperature scanning electron microscopy (LTSEM) is a promising measuring technique for probing the spatial distribution of the superconducting properties of the high-temperature superconducting (HTS) thin films. A theoretical analysis of the electron-beam irradiation on the HTS thin films in the LTSEM has been carried out. An inhomogeneously distributed grain array model has been applied in the analysis, and some numerical sim-ulations have been carried out on the electron-beam induced voltage (EIV) signals in the LTSEM experiments. The comparisons of our numerical results with the LTSEM experi-mental data indicate that it is quite reasonable to use a two-dimensional Josephson junction array for stimulating the inhomogeneous HTS thin film sample. Our numerical results also show that the EIV signals are influenced by the electron-beam power used in the LTSEM, and a reduction of the electron-beam power is suggested in order to eliminate the errors in estimating the local values of critical temperature Tc and critical current Ic by the sample temperature and the bias current at which the first EIV signal occurs. 相似文献
942.
对半导体器件封装的气密性失效进行了研究。发现,柯伐镀金盖板遭致电化学腐蚀是导致气密性失效的主要原因。对电解液的形成和电化学腐蚀机理进行了深入的分析。提出了防止腐蚀,提高器件气密可靠性的思路和方法。 相似文献
943.
钢铁表面锌系磷化膜的研究 总被引:3,自引:0,他引:3
本文采用SEM和TEM等测试手段,研究了四功能处理液不同条件下在钢铁表面上形成锌系磷化膜的形貌,晶体结构;采用EDS研究了磷化膜的化学成发,通过实验确定了Zn/P值在2.12~3.20时,磷化膜具有良好的耐蚀性。 相似文献
944.
A vertical cavity surface emitting semiconductor laser is described which uses zinc diffusion and partial disordering of the epitaxial output mirror to provide waveguiding for lateral mode control. Mode suppression ratios against higher order transverse modes as high as 36 dB have been observed.<> 相似文献
945.
在机动车磁卡收费系统中,红外车辆分离子系统是一种重要设备,它是由平行等距红外线族构成的平面检测系统,其性能直接影响收费系统的正常运转。本文介绍该子系统的设计并对系统性能进行分析,得出:子系统采取相关检测技术后,不仅能有效地抑制外界干扰、噪声,还具有抗相邻红外信号干扰能力。 相似文献
946.
947.
Huang JM Yang CS Zhao R Takahashi H Fukuyama Y 《Chemical & pharmaceutical bulletin》2004,52(1):104-107
Seven new seco-prezizaane-type sesquiterpenes were isolated from the methanol extract of the pericarps of Illicium merrillianum. Their structures were elucidated as 3-deoxypseudoanisatin (1), 2beta-hydroxy-3,6-dedioxypseudoanisatin (2), 8alpha-hydroxy-10-deoxycyclomerrillianolide (3), 10beta-hydroxypseudoanisatin (4), 10beta-hydroxycyclopseudoanisatin (5), 1,6-dihydroxy-3-deoxyminwanensin (6), and 8-deoxymerrilliortholactone (7) by analyses of their spectroscopic data and chemical transformation. Compounds 4 and 5 as well as 6 and 7 coexist as a keto/acetal equilibrated mixture in methanol solution. 相似文献
948.
本文根据三阶非线性极化率对光场偏振态的依赖关系,指出存在于受激四光子混频中各个波偏振状态之间的6种组合关系;应用耦合理论,分析了偏振组合在双折射相位匹配中的作用,计算了受激四光子混频的频移,解释了实验中多种模式组合下的“双线”输出及频移随双折射的变化。 相似文献
949.
This paper reports on the experimental investigation of the dynamic large deflection response of a portal frame impacted at its midspan by a body moving at a certain speed. Both the deflection and velocity vs. time curves of the midspan and the dynamic history of a number of desired locations were recorded during the process of response. On the basis of the test data, the momentum and kinetic energy conversion between the frame and the moving body in the impact process are realized, and the occurrence and expansion of plastic regions are described. Investigation results show that the initial collision is approximately ideally inelastic, and that the elastic deformation plays a considerable role in the response though the input energy is much larger than the maximum elastic energy capacity of the beam member; therefore, in a general impact, the energy ratio should not be regarded as a sufficient criterion for a rigid—plastic solution. The ratios of the impulse transferred to and the energy absorbed by the frame in the initial collision to that carried by the moving body before impact is only related to the ratiobetween the equivalent mass of the frame paticipating in the initial collision and the mass of the impacting body, having nothing to do with the impacting velocity to a certain extent. 相似文献
950.