12种道地中药中无机元素的含量测定

报道了用Ｘ射线荧光分析法测定的１２种道地中药，９８个不同产地样品中的Ｆｅ、Ｃｕ、Ｚｎ、Ｍｎ、Ｓｒ、Ｃａ、Ｋ含量。结果表明，不同种属，不同产地，不同品种中药元素量存在差异，不同加工方法影响中药中元素含量，同种中药中元素分布模式也不同。     

稀土壳聚糖杂化材料的制备、表征及抑菌活性研究

在室温条件下,以天然高分子材料壳聚糖和稀土纳米氧化物为原料,用表面接枝法制备了两种RE2O3-TDI-壳聚糖(TDI=甲苯-2,4-二异氰酸酯,RE=镧,钕)杂化复合物,借助红外(IR)、热重(DSC-TG)、扫描电镜(SEM)等测试技术对所制备的壳聚糖杂化材料的物化性能进行了表征,并采用培养基扩散法和营养肉汤稀释法等抑菌实验方法对其进行了抑菌活性实验,结果表明该稀土纳米壳聚糖杂化材料具有很好的热稳定性及抑菌性能。     

A unique reaction pathway of fluorine-substituted ethyl groups on Cu(111): successive alpha,alpha-fluoride elimination

Fluorine-substituted ethyl groups on Cu(111) were generated by thermal scission of the C-I bond in the adsorbed C2F5I. Temperature-programmed reaction spectrometry observed a novel pathway resulting in the evolution of C4F6 above 400 K. Among the various isomers, this product was identified as hexafluro-2-butyne. Although abstraction of two fluorine atoms from the starting Cu-CF2CF3 was required, Cu-CCF3 (trifluoroethylidyne) was favored over Cu-CF=CF2 (trifluorovinyl) as the intermediate because this ethyl-ethylidyne-butyne pathway was suppressed on a Cu(100) surface devoid of the key threefold hollow binding sites for ethylidyne. Once formed, perfluoroethylidyne readily coupled to afford a tightly surface-bound hexafluoro-2-butyne up to 400 K. Therefore, the C-F bonds adjacent to the metal were found to be more susceptible to the bond activation, leading the chemisorbed perfluoroethyl to eliminate two F atoms successively from the alpha-carbon. This preference for alpha-elimination rather than beta-elimination (the most favorable route in hydrocarbons) may be quite general for metal surface-mediated reactions involving fluorinated alkyl groups.     

星体几何不等式的一种抽象形式

本文研究了拓广型星体的对偶Minkowski不等式.利用星体族的径向乘法、径向幂运算和多元型对偶混合体积的概念和积分的方法,得到了对偶Minkowski不等式的多元抽象形式,并将所得结果应用到积分几何学,得到了一个正数列非任意凸体的弦幂积分列的判定条件.     

面向微穿孔板吸声结构和吸声特性混合设计的软件平台

微穿孔板吸声结构是由微穿孔板与板后空腔组成的共振吸声结构,被认为是继多孔吸声材料之后发展起来的最有吸引力的吸声结构,其吸声特性与结构参数孔径d、板厚t、孔距b及空腔深度D有关,如何按需设计一个有效的微穿孔板吸声结构已成为目前研究的热点。本文从微穿孔板吸声结构和吸声特性混合设计的角度出发,使用面向对象的编程语言C++开发了微穿孔板吸声结构设计平台。与以往设计方法不同,本文开发的软件平台综合考虑了结构参数和吸声特性参数两方面的限制,根据实际应用要求平衡微穿孔板吸声结构的最大吸声系数与吸声带宽之间的制约关系,并以饱满的吸声曲线为目标,提供满足混合设计要求的优化结构参数。     

二维二氧化硅改性聚环氧乙烷基固态聚合物电解质用于增强锂离子电池性能

通过改性由酸蚀二维蛭石制备的二维二氧化硅,得到带正电荷的二维介孔二氧化硅(PSN⁺)纳米片,并将PSN⁺用作聚环氧乙烷(PEO)基固体聚合物电解质(SPEs)的填料。由于PSN⁺具有丰富的正电荷,PSN⁺与锂盐解离的阴离子能够有效结合,从而促进锂离子的运输,获得较好的锂离子转移数。在50 ℃时,基于PSN⁺的SPEs表现出较高的离子电导率(7.5×10^-5 S·cm^-1),锂离子迁移数为0.30,稳定电压窗为4.41 V。因此,组装后的LiFePO₄锂电池在50 ℃、0.2C下具有优异的初始放电比容量(155.7 mAh·g^-1),在循环100次后容量保持率为97.1%。     

WO3/CeO2-ZrO2, a promising catalyst for selective catalytic reduction (SCR) of NOx with NH3 in diesel exhaust

A WO3/CeO2-ZrO2 catalyst system was discovered for selective catalytic reduction of NOx with NH3; the catalyst (10 wt% WO3 loading) showed nearly 100% NOx conversion in a temperature range of 200-500 degrees C, at a space velocity of 90 000 h(-1) in a simulated diesel exhaust containing 550 ppm NOx (NO : NO2 feed ratio at 1.0), 10 vol% H2O and 10 vol% CO2; the catalyst also exhibited high temperature stability.     

Removal of phosphate from aqueous solution by zeolite synthesized from fly ash

Fifteen Chinese fly ashes were converted hydrothermally into zeolites, and phosphate immobilization capacity (PIC) of the synthesized zeolites and the corresponding raw fly ashes were determined using an initial phosphate concentration of 1000 mg/L. Results showed that there was a remarkable increase in PIC (from 1.2 to 7.6 times) following the synthesis process. Fractionation of immobilized phosphorus indicated that Fe+Al-P increased most significantly and consistently among all the phosphorus fractions following the conversion of fly ash to zeolite. The PIC and Ca+Mg-P were closely related to Ca content (with r values of 0.9683 and 0.9651, respectively) rather than Mg content (with r values of 0.3920 and 0.3212, respectively). The r values of PIC and Fe+Al-P with Fe content (with r values of 0.4686 and 0.6385, respectively) were higher than those with Al content (with r values of -0.7857 and -0.3770, respectively). Although calcium and iron components were mainly involved in phosphate immobilization, there was no significant change of Ca and Fe content following the conversion of fly ash to zeolite. Increase in dissociated Fe(2)O(3) and specific surface area probably accounted for the enhancement in PIC of synthesized zeolites compared with corresponding fly ashes. The PIC value of zeolites showed a significant correlation with dissociated Fe(2)O(3) (r=0.6186). The specific surface area increased 26.0-89.4 times as a result of the conversion of fly ash to zeolite. The maximum removal of phosphate occurred within different pH ranges for zeolites which were synthesized from high, medium and low calcium fly ashes and this behavior was explained by the reaction of phosphate with calcium and iron components.     

Determination of inorganic elements in iliac crests of rabbits by NAA

This paper deals with the osteoporosis model of New Zealand rabbits in order to study the function of inorganic elements for women patients with osteoporosis. The thirty cases of iliac crest are collected and determined using neutron activation analysis (NAA). The results show that the fluorine concentrations in the experimental group are higher than those in control group and the magnesium concentrations are significantly lower (P<0.001), but the concentrations of K, Na, Ca, Ba, Mn, Sr show no remarkable difference. Combined with the serum biochemical markers of bone formation and resorption, the physiological functions of some metal elements in bone are also discussed.     

Determination of bone mineral density in selected residents by DEXA

Bone mineral density (BMD) determination has been performed in 210 selected Shanghai residents of both sexes of age range 15–50 using Hologic QDR-2000 dual energy X-ray absorptiometry (DEXA). The results showed that in female groups the peak value of L1-L4 BMD was 1.023 g/cm² at the age of 31–35, but in the male groups it was 0.971 g/cm² aged 26–30 and the peak period lasted till the group aged 46–50. The similar conclusion has also obtained by further statistics.