含氮配体Co、Fe配合物的合成、结构及性质

报导了四个单核Co（Ⅱ）和Fe（Ⅱ）的配合物[Co（L1）2]（ClO4)2·（CH3CN）（1）,[Fe（L1）2]（ClO4）2·（H2O）（2）,[Co（L2）]（ClO4）2（3）,以及[Fe（L2）]（ClO4）2·2H2O（4）,（其中L1＝4’-苯基-2,2’：6’,2”-三联吡啶,L2＝N,N,N-三-（2-（2-吡啶甲叉氨基）乙基）胺）的合成和性质,以及配合物1、3的晶体结构．配合物1和3的晶体都属于单斜晶系．它们的晶胞参数分别为：1a＝1．0855（4）nm,b＝1．6201（5）nm,c=2.5236（5）nm,β＝92．63（2）°,V＝4．433（1）nm3;3a=2.8351（8）nm,b＝1．0670（3）nm,c＝1．9255（5）m,β＝101．03（4）°,V＝5717（2）nm3．2和4的氧化还原电位分别为E＝0．78V和0．63V‘它们的d-d跃迁吸收最大值分别位于565和521nm处．     

沸石分子筛的骨架同晶置换(Ⅰ)——NH4BF4溶液中沸石分子筛的脱铝补硅

通过NH₄BF₄溶液对沸石分子筛进行脱铝补硅,对所得产物已用多种技术表征。结果表明,在此处理过程中,产物的硅铝比随溶液中NH₄BF₄浓度的增加而增加,热稳定性随之增强,酸量随之减弱,未发现硼对骨架元素的同晶置换,而发生了脱铝补硅作用。     

Deformation mechanisms of nanoclay‐reinforced maleic anhydride‐modified polypropylene

Fracture properties and deformation mechanisms of nanoclay‐reinforced maleic anhydride‐modified polypropylene (MAPP) were investigated. Elastic–plastic fracture mechanics was employed to characterize the toughness in light of substantial postyield deformation for the reinforced MAPP. Upon introduction of 2.5 wt % clay loading in maleated MAPP, it was observed that tensile strength, modulus, and fracture initiation toughness concomitantly increased substantially. Continued increase in clay loading thereafter only led to stiffening and strengthening effects to the detriment of fracture toughness. A plot of the J‐integral initiation fracture toughness versus the plastic zone size demonstrated that toughening arose from plastic deformation in the reinforced matrix. Careful examination of deformed tensile specimens using small angle X‐ray scattering (SAXS) showed 2.5 wt % clay gave rise to the highest equatorial scattering, which indicates the presence of microvoids in the matrix. The SAXS results were consistent with that shown in subcritically loaded crack‐tip deformation zone using transmission electron microscopy. Thus, both macroscale three‐point bend fracture data and SAXS results led us to consistent findings and conclusions. Further increase in clay loading above 2.5 wt % reduced the scattering the matrix plasticity and thus the fracture toughness. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2759–2768, 2004     

Color octet contribution in exclusive P-wave charmonium decay into octet and decuplet baryons

In the last years, the need for the color octet state in inclusive P-wave charmonium decay has been firmly established. However, the implications of this in the corresponding exclusive reactions have not been fully recognized. We argue for the necessity of the color octet in P- and higher-wave quarkonium decay. Using a set of phenomenologically constructed baryon wave functions, we consider the decay into an octet and decuplet baryon–antibaryon pair. By doing so, we subject the wave functions to a test of applicability. We show that the color singlet component alone is insufficient to account for the experimental measurements, and only by including the color octet contribution can the partial theoretical decay widths be brought into the range of the data. By the present and earlier applications of the set of wave functions, these show themselves to be reasonable model wave functions at around the scale –20 GeV. Received: 1 March 1999 / Published online: 18 May 2000     

A true random number generator based on mouse movement and chaotic cryptography

True random number generators are in general more secure than pseudo random number generators. In this paper, we propose a novel true random number generator which generates a 256-bit random number by computer mouse movement. It is cheap, convenient and universal for personal computers. To eliminate the effect of similar movement patterns generated by the same user, three chaos-based approaches, namely, discretized 2D chaotic map permutation, spatiotemporal chaos and “MASK” algorithm, are adopted to post-process the captured mouse movements. Random bits generated by three users are tested using NIST statistical tests. Both the spatiotemporal chaos approach and the “MASK” algorithm pass the tests successfully. However, the latter has a better performance in terms of efficiency and effectiveness and so is more practical for common personal computer applications.     

Fatigue testing of condoms

Tests currently used for condoms are surrogates for the challenges they face in use. The tests involve looking for holes and slow stretching to break. This article describes a test that adds cyclic strain to a level well below breakage, and examines the differences among brands and types of condom. It is shown that there are very significant differences in resistance to cyclic straining. Such a test could be developed into a standard test for condom acceptability.     

Determination of inorganic and organic anions in xylem saps of two contrasting oilseed rape (Brassica juncea L.) varieties: Roles of anions in long-distance transport of cadmium

By optimizing chromatographic conditions of an ion chromatographic system, we identified and measured the major inorganic and organic anions (chloride, nitrate, malate, sulfate, phosphate and citrate) in the xylem saps of two contrasting tolerant oilseed rape (Brassica juncea L.) varieties (the high Cd-accumulating genotype Xikou Huazi and the low Cd-accumulating genotype Liangting Huazi). Cadmium concentrations in xylem saps were determined by graphite furnace atomic absorption spectrometry. By analyzing the relationship between anion and cadmium concentrations, we considered that the relatively low phosphate concentrations in Xikou Huazi xylem saps might relate to the relatively high xylem transport of Cd for this genotype, and malate in oilseed rape xylem saps seemed to participate in the long-distance Cd translocation process. Our work might not only be very useful for understanding the mechanisms of Cd hyperaccumulation for Xikou Huazi, but also very beneficial for future application of Xikou Huazi in phytoremediation.     

Synthesis and evaluation of 8,9-amido analogs of geldanamycin

Amido analogs of geldanamycin, an ansamycin anticancer agent, were designed, synthesized, and assayed with SKBR3 cells, in which stability of HER2 receptor tyrosine kinase is dependent on the chaperone Hsp90. An amide was employed as a trisubstituted alkene isostere at the C8,9 position, which provided for a simplified, convergent synthesis through two major fragments, an aniline-amine left-hand portion and a dicarboxylic acid right-hand piece.     

Testing coefficients of AR and bilinear time series models by a graphical approach

AR and bilinear time series models are expressed as time series chain graphical models, based on which, it is shown that the coefficients of AR and bilinear models are the conditional correlation coefficients conditioned on the other components of the time series. Then a graphically based procedure is proposed to test the significance of the coefficients of AR and bilinear time series. Simulations show that our procedure performs well both in sizes and powers. This work was supported by the Hong Kong Polytechnic University Research Council, the National Natural Science Foundation of China (Grant No. 10671044) and the Science and Technology Bureau of Guangzhou Municipal Government of China (Grant No. LSBH-017)