The geometry effects for stress intensity factor of sandwich specimen for measuring interfacial fracture toughness

The interfacial stress intensity factors for three types of sandwich specimens: the single edge crack tensile specimen, the three point bend specimen and the four point shear specimen were obtained by the finite element analysis and compared with the asymptotic solutions. The results show that the geometric effect for mode II specimen is larger than mode I specimen. The limit curves for geometry factor equal to 1.05 were obtained to indicate the usable range of validity of the asymptotic solution.     

Beam test of the CsI(Tl) calorimeter for the BELLE detector at the KEK-B factory

We studied the performance of a prototype electromagnetic calorimeter for the BELLE detector at the KEK proton synchrotron for an energy range of 0.25–3.5 GeV. The prototype consisted of an array of 6 × 5 CsI(Tl) crystals with 30 cm length (16.2 radiation lengths) and about 6 cm × 6 cm cross section. The scintillation light of each CsI(Tl) crystal was read out by two large-area PIN photodiodes and charge-sensitive preamplifiers attached at the rear face of the crystal. We measured the energy and position resolution for electrons and the e/π separation for two sets of matrix configurations: one corresponded to the center and the other to the edge of the barrel calorimeter. The overall performance measured by the test proves that the prototype calorimeter is satisfactory for the use in the BELLE detector.     

Fe－Cu包埋团簇的制备及其微观结构的研究

基于溅射－气体－聚集（ＳＧＡ）形成团簇的原理，提出了蒸发－气体－聚集（ＥＧＡ）共沉积方法，并在方华膜载网上成功地制备了Ｆｅ－Ｃｕ纳米磁性包理团簇样品。ＴＥＭ／ＥＤ分析表明，样品中Ｆｅ团簇被Ｃｕ原子所包裹，形成了以Ｆｅ团簇为芯，Ｃｕ膜为壳的良好的芯－壳式包埋结构。当衬底温度由２５℃变化到２００℃时，样品形貌由弥散状过渡到集团状，直至形成大的块状；其结构也相应的由Ｆｅ－Ｃｕ多晶共存变化为一种不规则的单晶形态。     

A Study of the Specific Heats of the Compounds in the Sm_2O_3-BaO-CuO System

By means of X-ray diffraction and adiabatic scanning calorimeter,the specific heatsof five compounds in the Sm_2O_3-BaO--CuO system,such as Sm_2BaO_4,Sm_2CuO_4,BaCuO_4,Sm_2BaCuO_5,SmBa_2Cu_3O_(7-x),from -150℃ to 800℃ have been measured.It is found that the specific heats ofthese compounds increase smoothly with the increase of temperature.     

Use of subunit-specific antisense oligodeoxynucleotides to define developmental changes in the properties of N-methyl-D-aspartate receptors

Antisense oligodeoxynucleotides were used to determine whether alterations in the expression of N-methyl-D-aspartate (NMDA) receptor subunit mRNA are responsible for developmental changes in the sensitivity of receptors to agonists and antagonists. Xenopus laevis oocytes were injected with mRNA prepared from neonatal and adult rat cerebral cortex, and the effects of agonists and antagonists were determined under voltage-clamp conditions. Glycine-site antagonists like 7-chlorokynurenate and glutamate-site antagonists like CGP-39653 were more potent at NMDA receptors expressed from mRNA from adult rat cerebral cortex than those expressed from mRNA from 1-day-old rat. NMDA receptors from 1-day-old rat cerebral cortex were more sensitive to activation by glycine than were receptors from adult rat cerebral cortex. 7-Chlorokynurenate and CGP-39653 were more potent inhibitors of responses seen with heteromeric NR1/NR2A receptors than with NR1/ NR2B receptors. Conversely, heteromeric NR1/NR2B receptors were more sensitive to activation by glycine than were NR1/NR2A receptors. We previously described a delay in the expression of the NR2A subunit in developing rat brain. Anti-sense oligodeoxynucleotides were used to determine whether the delayed expression of the NR2A subunit underlies changes in pharmacological properties observed during development. The properties of receptors seen when adult brain mRNA was coinjected with antisense oligodeoxynucleotides against the NR2A subunit were similar to those found in receptors from 1-day-old rat brain. These data suggest that changes in the sensitivity of NMDA receptors to antagonists and to glycine seen during development are a result of alterations in the expression of different species of NR2 subunit mRNA.     

Finite twist and extension of a cylindrical elastic membrane

Summary We consider a circular cylindrical membrane subjected to longitudinal extension and twist. The associated equilibrium deformation is considered to be axisymmetric and the analysis is based on a direct two-dimensional formulation. Wrinkling of the membrane is taken into account in an approximate way by introducing arelaxed strain energy function derived from the neo-Hookean strain energy for isotropic elastic solids. Analytical formulae for wrinkled parts of the membrane are used to corroborate the results of a numerical treatment of the full boundary value problem.Dedicated to the memory of A. C. Pipkin     

数字式速度比例同步电脑控制系统

数字式速度比例同步控制系统，是把先进的交流变频调速技术，微电子技术和节能效果显著的永磁同步电机融为一体组成的性能优良的调速控制系统。该系统具有调速精度高调整范围大、稳定性好、抗干扰能力强、调整方便、节电效果显著等一系列优点。本文详细介绍了该系统的工作原理，并通过应用实例和分析对比，阐述该系统的优越性。     

稠油油藏的注汽量预测

利用HCZ预测模型，可对已开发油田的年产量和累计产量进行全程预测，并且在实际应用中取得了较好的预测结果。本文结合稠油田的实际情况，推导出HXZ预测模型在热采中注汽参数的预测公式。结合曙光油田曙1－7－5块的开发数据进行了预测，效果较好。     

淀积条件对GDa—SiNx薄膜电学特性的影响

本文讨论了用辉光放电法制备氮化硅薄膜时衬底温度、射频功率和气体流量比对薄膜的电导率、介电常数和击穿强度的影响。通过优化生长条件，制备了优质非晶氮化硅薄膜，其介电常数为７．５、击穿强度为５．５ＭＶ／ｃｍ、电导率为１０－１３（Ωｃｍ）－１。