北京谱仪端盖簇射计数器工作气体的研究

为使北京谱仪端盖族射计数器更好地工作在自猝灭流光ＳＱＳ模式下，提高其能量分辨以及线性等指标，用Ａｒ，ＣＯ２，Ｌｓｏｂｕｔａｎｅ三元工作气体对探测器的工作性能进行了仔细研究，找出了一适合于主雇地数器的工作气体，此外，还研究了异丁的纯度对探测器性能的影响。     

辐射制备缓释抗癌药阿糖胞苷的研究

报告了甲基丙烯酸酯类在室温下进行辐射聚合制备缓释抗癌药阿糖胞苷（Ａｒａ－Ｃ）的研究结果。结果表明，不仅亲水性单体，而且疏水性单体（包括ＭＭＡ、ＥＭＡ和ＢＭＡ等）都可用于辐射固化。加入到亲水性基质中的疏水性单体可以延缓药物的离体释放，其顺序是ＭＭＡ＜ＥＭＡ＜ＢＭＡ，央ＭＭＡ－ＨＥＭＡ共聚物中，Ａｒａ－Ｃ释放率随着基质中的ＭＭＡ含量增加而降低。药物的离体释放还受许多困素的控制，结果显示：药物释放量随着     

Microstructure study of Sm,Mn-modified PbTiO3 piezoelectric ceramics by XRD profile-fitting technique

By using the X-ray diffraction profile-fitting technique, the microstructures of Sm, Mn-modified PbTiO₃ piezoelectric ceramic discs, including ferroelectric domain sizes, microstrains, and their variations with the poling strength have been quantitatively investigated. The results manifest that the modified PbTiO₃ ceramics contain a high density of domain walls due to the presence of finely-divided coherent domain structures (tens of nanometres in dimension). The poling treament can evidently influence the domain-size distribution, with a more homogeneous microstructure being developed; however, it simultaneously causes high anisotropic microstrains within the structure which, together with the high density of domain walls, is expected to be responsible for the unusual high electromechanical coupling properties possessed by this material.     

Ka-band solid-state pulsed Gunn oscillator and power combiner

GaAs Gunn diodes were fabricated for pulse source application at 8 mm wave band and operated with pulsewidths of 0.05 to 2.0 microseconds and duty cycles of 0.001 to 0.01. Peak pulse output power levels of 0.8–1.2W are achieved and the maximum available power is 1.6W with the highest efficiency of 6.5 percent. A simple and compact pulsed power combiner is also given in this paper.     

27keV Ar~+斜入射时的Cu-Au合金溅射实验角分布

用27keV Ar~+分别在垂直和倾斜入射情况下,轰击了Cu-Au(30wt％)合金样品,测量了Cu和Au原子的溅射角分布。角分布是用卢瑟福背散射(RBS)技术分析Al捕获膜上的Cu-Au沉积成分而定量得到的。结果表明:(1)在Ar~+倾斜(θ=40°)入射时,Cu原子择优发射,且程度比垂直入射(θ_r=O°)时增强:(2)倾斜入射时,Cu原子的角分布显示出在接近于样品表面法线方向的发射角范围内(θ<45°),发射机率比垂直入射时减小。     

A vectorial boundary element method analysis of integrated optical waveguides

In this paper, a new vectorial boundary element method is introduced and applied to the modal analysis of dielectric waveguides with piecewise homogeneous refractive indexes. The procedure, which is free of spurious modes, determines the full field distribution from the longitudinal fields at the refractive index boundaries. Singular kernels are evaluated through series solutions while the electric field discontinuity at corners is accommodated through either a grid refinement technique or a semianalytic approach. Our formalism generates propagation constants and modal field distributions for several representative refractive index profiles with far higher accuracy than standard finite-difference or finite-element procedures.     

首钢2号高炉的技术进步

介绍首钢2号高炉大修采用的新技术、开炉操作和投产以来的生产情况。     

小纸层析法快速测定^99mTc—HMPAO放射化学纯度

采用小纸层析系统１：１的氯仿／四氢呋喃展开剂分析＾９９ｍＴｃ－ＨＭＰＡＯ的放射化学纯度，并与两个薄层析系统和一个纸层析系统的方法作比较。配对ｔ检验结果表明两种方法测定的放射化学纯度无显著差异；放射化学纯度在７４．２％－９６．４％，小纸层析法与薄层／纸层析法紧密相关，回归公式ｙ＝１．００６ｘ－０．３２３。