磷锑钼抗光度法测定分子筛中的磷

研究建立了以磷（V）－洒石酸锑钾－钼酸铵－抗坏血酸显色体系测定分子筛中磷含量的新方法，提出了测定磷的最佳条件，在0.22mol·L^-1硫酸介质中，该显色体系最大吸收波长位于704nm，该波长处表观ε＝7.82×10^3L·mol^-1·cm^-1，磷（V）含量在0－0.90μg/mL浓度范围内遵守比耳定律。本法用于分子筛中磷含量的测定，获得了令人满意的结果。     

Shockwave Visualization Using Holographic Interferometer

High-speed holographic interferometry was employed to visualize and record Shockwave phenomena. We performed three kinds of holographic interferometry for visualization and recording of the propagation of a Shockwave: a real-time holographic interferometer with a high-speed framing camera, a real-time holographic interferometer with a high-speed streak camera and a double-pulse laser holographic interferometer with a dual-reference-beam module. The experimental results were compared and their advantages and disadvantages are discussed. The experimental results clearly show the high-speed Shockwave propagation and give the feasibility of quantitative interpretation of high-speed gas-dynamics.     

2，5-二烷基-1，4-苯二酚类衍生物的新合成方法

研究了合成2，5-二烷基-1，4-苯二酚衍生物的新方法，该方法是以2-取代烷 基1，4-环已二酮为原料，在LiCl催化下，与各种醛缩合反应就得2，5-二烷基-1， 4-苯二酚衍生物，是一种由非芳香环化合物合成2，5-二烷基-1，4-苯二酚衍生物 的新方法。应用该方法简便地合成了天然化合物η-生育酚。     

暗物质寻找实验中CsI(Tl)晶体反符合探测器实验研究

一个正在建设的位于韩国Y2L地下实验室的低能暗物质探测实验中, 采用了CsI(Tl)晶体反符合探测器作为主动屏蔽体. 本工作对CsI(Tl)晶体反符合探测器的实验性能进行了研究. 通过FADC系统记录的脉冲波形数据, 研究了探测器的能量分辨率和波形甄别的能力; 研究相同能量γ射线入射到反符合探测器不同位置的相对光输出将有助于选择探测器的工作参数; 为了解晶体自身放射性对暗物质测量的影响, 利用低本底HPGe探测器对CsI(Tl)晶体内部的放射性进行了测量, 得到晶体内部Cs同位素的放射性活度. 探测器系统进行了约18d的试运行取数. 实验数据表明, CsI(Tl)晶体探测器的反符合效率约为31% HPGe探测器的本底计数率水平约为133cpd. 为了进行暗物质探测研究, 需要采取有效的方法进一步降低探测器的本底水平.     

可紫外光固化的聚乙烯基硅氮烷合成与表征

采用带丙烯酸酯基团的烯丙基溴化合物(4-溴丁烯酸乙酯)和聚乙烯基硅氮烷发生取代反应,实现了丙烯酸酯基团在聚乙烯基硅氮烷主链上的链接.采用质子核磁共振谱(1H-NMR)和二维质子核磁共振谱(2D-1H-1H-NMR)对分子结构进行了表征,采用光学差热分析仪(Photo-DSC)和傅立叶转换红外光谱仪(FT-IR)测试了改性高分子的光敏性能,用热重分析仪(TGA)分析了产物在高纯氮气氛围下的陶瓷收率.结果表明,通过分子改性,交联固化时间从改性前的20min减少到1min之内,功能化的聚乙烯基硅氮烷可以在光刻蚀工艺中作为负性光刻胶使用.     

ESTIMATES OF LOWER CRITICAL MAGNETIC FIELD AND VORTEX PINNING BY INHOMOGENEITIES IN TYPE Ⅱ SUPERCONDUCTORS

The effect of an applied magnetic field on an inhomogeneous superconductor is studied and the value of the lower critical magnetic field Hc1 at which superconducting vortices appear is estimated. In addition, the authors locate the vortices of local minimizers, which depends on the inhomogeneous term a(x).     

In Situ Generation of Cationic Methylzirconium Complexes from rac-(EBI)Zr(NMe2)2 and NMR-Scale Polymerization of Propylene

ABSTRACT

Sequential NMR-scale reactions have been carried out in order to generate cationic methylzirconium complexes by the reaction of rac-(EBI)Zr(NMe₂)₂ (rac- 1 , EBI = Et(indenyl)₂) with methylaluminoxane (MAO) or various anionic compounds. By reacting 40 equiv. of MAO with rac- 1 in an NMR tube containing CD ₂CI₂ as a solvent at room temperature, rac- 1 is completely activated to give stable cationic methylzirconium complexes, [(EBI)ZrMe]⁺[MAO]^? which polymerize propylene to isotactic polypropylene (iPP). The formation of the cationic species is achieved after rac- 1 is methylated to form rac-(EBI)ZrMe₂ (rac- 2 ) by MAO and/or free Al₂Me₆ contained in MAO. The same sequential reaction has been performed by using rac(EBI)ZrCl₂ (rac- 3 ) for the comparison. MAO cannot generate the cationic species at the same reaction conditions in the reaction of rac- 3 and MAO, mainly due to the difficulties of methylation of rac- 3. Ansa ziconocene amide rac- 1 is stoichiometrically methylated by 2 equiv. of Al₂Me₆ to give rac- 2. Introduction of 1 equiv. of noncoordinating to the solution mixture of rac- 1 and 2 equiv. of Al₂Me₆ leads to the formation of stable cationic methylzirconium species, [rac-(EBI)Zr(μ-Me)₂AlMe₂]⁺. NMR-scale polymerizations have been carried out by adding a small amount of liquid propylene to these cationic species. The meso pentad values of iPP isolated in these polymerizations are in the range of 80.2–84.7%. By changing the order of sequential reaction, i.e., by reacting rac- 1 with noncoordinating anions prior to methylation by Al₂Me₆, the yield to give cationic methylzirconium species is decreased. Coordinative anions such as [HNMe₂Ph][BPh₄] and [HNBu₃][BP₄] are less effective for the generation of the active zirconium cations than noncoordinating anions. The amount of MAO needed to activate rac- 1 can be decreased by the pre-methylation of rac- 1 by Al₂Me₆.     

New Diarylheptanoid from the Barks of Alnus japonica Steudel

A new diarylheptanoid glycoside, 1,7-bis-（3,4-dihydroxyphenyl）-5-hydroxyheptane- 3-O-β-D-xylopyranoside （1）, together with nine known diarylheptanoids （2-10） were isolated from the fresh bark of Alnus japonica which is a species of the genus Alnus species, growing throughout Korea.     

ANALYSIS OF SOUND TRANSMISSION THROUGH PERIODICALLY STIFFENED PANELS BY SPACE-HARMONIC EXPANSION METHOD

An analysis method is developed to study sound transmission characteristics of a thin plate stiffened by equally spaced line stiffeners. The dynamic equation that describes the vibro-acoustic response of the system is derived by expanding the structural and acoustic responses in terms of the space harmonics and by using the virtual energy method. The series solution can be considered as the exact solution because the structural and acoustic-structural coupling effects in the system are fully considered and the solution converges. Parameter studies are conducted for major design parameters to understand the characteristics of the system.