超软X射线流气式正比计数管

介绍了一种用于测量183～933eV超软X射线的圆柱形、侧窗式、流气式正比计数管,工作气体是0.11MPa的P-10气体或氦气-丙烷混合气体。计数管内径为φ25mm,直径为φ0.3mm的入射窗是由厚度80～90μgcm~2聚乙烯甲醛制成的。该计数管的特点:(1)薄窗,对软X射线透过率高。(2)流气式,工作寿命长。(3)能量分辨率好。(4)计数率高(1×10~(14)个/s)。(5)可测能区宽(0.183～10keV)。(6)可以方便更换窗膜材料、厚度及窗口直径。近几年来该计数管已经为高强度低能X光源提供较好监测。     

The Existence of Periodic Orbits for Higher Dimensional Autonomous Systemswith Small Perturbations

ＴｈｅＥｘｉｓｔｅｎｃｅｏｆＰｅｒｉｏｄｉｃＯｒｂｉｔｓｆｏｒＨｉｇｈｅｒＤｉｍｅｎｓｉｏｎａｌＡｕｔｏｎｏｍｏｕｓＳｙｓｔｅｍｓｗｉｔｈＳｍａｌｌＰｅｒｔｕｒｂａｔｉｏｎｓＪｉａｎｇＬｉｑｉｎｇ（蒋里强）；ＺｈｏｕＹｉ（周毅）；ＦａｎＹｅ（范晔）（...     

聚醚醚酮链结构与反应的模型化合物的量子化学研究

利用ＡＭ１方法对聚醚醚酮模型化合物全优化，结果为：芳环平均相互扭转角为３３．０度，桥键角１１７．０－１１８．０度，其分子结构拓扑图形表明：所有苯环（核）为平面构型，但其内角扭曲；其氢原子对苯环构型无实质性贡献，在更长链的计算中，冻结苯核与氢原子也得出满意结果，根据Ｍｕｌｌｉｋｅｎ键序与电荷讨论了醚交换与磺化反应。     

颗粒增强复合材料热应力分析的双层嵌套模型

建立了一个把增强颗粒球和基体空心球嵌入等效复合介质空腔中的“双层嵌套模型”,研究了颗粒增强材料自高温冷却下来时,不同相中热应力的分布特点。推出了热应力在弹性和弹塑性状态的各种表达式。研究表明,随着温度降低,增强体受到压应力,基体材料中存在的静水应力为拉应力。温度继续下降,将出现自增强颗粒与基体界面向外扩展的屈服区。随增强相体积分数增大,增强颗粒受到的压应力和基体中的静水拉应力减小,增强颗粒与基体界面屈服的起始温差增大,而基体材料全面屈服的温差却减小。     

Viscosity solution theory of a class of nonlinear degenerate parabolic equations II. Lipschitz continuity of free boundary

In [1] we construct a unique bounded Hölder continuous viscosity solution for the nonlinear PDEs with the evolutionp-Laplacian equation and its anisotropic version as typical examples. In this part, we investigate the Lipschitz continuity of the free boundary of viscosity solution and its asymptotic spherical symmetricity, however, this result does not include the anisotropic case.This research is supported by the National Natural Sciences Foundation of China.     

HL—1装置等离子体密度反馈实验

本文叙述HL-1装置用反馈脉冲补充送气方式控制等离子体密度的方法及实验结果。给出了在固有的物理实验条件下的最佳反馈方式,实现了对密度的有效控制及反馈。讨论了在不同密度条件下的几种反馈方式及反馈系统尚存在的不足之处。     

Poly(phenylene vinylene)‐based copolymers containing 3,7‐phenothiazylene and 2,6‐pyridylene chromophores: Fluorescence sensors for acids,metal ions,and oxidation

A novel copolymer, poly(N‐hexyl‐3,7‐phenothiazylene‐1,2‐ethenylene‐2,6‐pyridylene‐1,2‐ethenylene) ( P3 ), containing N‐hexyl‐3,7‐phenothiazylene and 2,6‐pyridylene chromophores was synthesized to investigate the effect of protonation, metal complexation, and chemical oxidation on its absorption and photoluminescence (PL). Poly(N‐hexyl‐3,8‐iminodibenzyl‐1,2‐ethenylene‐1,3‐phenylene‐1,2‐ethenylene) and poly(N‐hexyl‐3,7‐phenothiazylene‐1,2‐ethenylene‐1,3‐phenylene‐1,2‐ethenylene) ( P2 ), consisting of 1,3‐divinylbenzene alternated with N‐hexyl‐3,8‐iminodibenzyl and N‐hexyl‐3,7‐phenothiazylene, respectively, were also prepared for comparison. Electrochemical investigations revealed that P3 exhibited lower band gaps (2.34 eV) due to alternating donor and acceptor conjugated units (push–pull structure). The absorption and PL spectral variations of P3 were easily manipulated by protonation, metal chelation, and chemical oxidation. P3 displayed significant bathochromic shifts when protonated with trifluoroacetic acid in chloroform. The complexation of P3 with Fe³⁺ led to a significant absorption change and fluorescence quenching, and this implied the coordination of ferric ions with the 2,6‐pyridylene groups in the backbone. Moreover, both phenothiazylene‐containing P2 and P3 showed conspicuous PL quenching with a slight redshift when oxidized with NOBF₄. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1272–1284, 2004     

Photoluminescence properties of the composite of porous alumina and poly (2,5-dibutoxy-1,4 phenylenevinylene)

The spin coating method was used to assemble polymer (Poly (2,5-dibutoxy-1,4-phenylenevinylene)) (DBO-PPV) into the pores of porous alumina which was prepared by anodization. Four peaks in the photoluminescence (PL) spectra of the composite, with contributions from the DBO-PPV and porous alumina, were found. It was also found that the light emitting from the porous alumina could excite the photoluminescence of DBO-PPV. The nanometer effect of the porous alumina can lead to a blue shift of 90 nm of the PL peaks of DBO-PPV.