绕圆柱体自由表面磁流体流动和传热的研究

本文对在不同雷诺数下,绕圆柱体的磁流体自由表面流动及传热进行了模拟,分析了磁场对绕流圆柱尾迹和涡分离的影响,获得了两种雷诺数下的电磁力密度、流场和温度场分布。结果表明,磁场不仅影响了流动的形态,而且对湍流有抑制作用,降低了自由表面的更新机制,从而减少了传热能力;在相同的Hartmann数下,相比低雷诺数下的流动换热情况,高雷诺数下的湍流不能被完全抑制,自由表面与尾迹的相互作用也较强,因而自由表面换热也较强。     

仲态电子偶素湮没辐射能量的改进测量

用充氧气的气凝硅胶作仲态电子偶素源,用¹⁹²Ir精密γ能量作标准,以时间选择能谱仪和滑动比较法改进测量仲态电子偶素2γ湮没能量,得到hv=510995.34±0.69eV.经电子偶素结合能修正,得正、负电子对静止质量,与电子质量比较,表明正、负电子质量在1.4ppm内一致.     

茴香酸乙酯的合成

从茴香油生产茴香醛的废渣、废液中提取副产品茴香酸，合成茴香酸乙酯。对合成条件进行了研究，取得了满意的结果。     

Interaction of gravitational waves with a superconducting cylindrical antenna

In this paper we investigate the effects of gravitational waves (GW) on a superconducting cylindrical antenna (S-antenna). We suggest that the electric fields induced by GW of dimensionless amplitudeh - 10^–24 in the interior of existing cylindrical antenna might be detectable.     

溶剂萃取法制备碳酸盐的热力学讨论

向金属氯化物(Ⅰ)的水溶液中通入CO_2气体,以期制备相应的碳酸盐和酸式碳酸盐,在常温常压下,体系的△G>0,反应几乎是不可能的。向反应体系中加入有机溶剂(S),使生成的HCl即被萃取,可促进Ⅰ的继续转化。分析计算表明,S对HCl必须有很强的萃取能力,其K_萃须在10~5以上。研究了加入有机溶剂N_(235)前后,体系的热力学状态、函数及其变化。加入N_(235)后,K_萃值增大了5个数量级。考察了温度、时间和通气次数对系统热力学性质的影响。根据反应的耦合原理和热力学分析,提出萃取剂选择的原则。结合实验数据的估算说明:溶剂萃取法由Ⅰ和CO_2制备碳酸盐的工艺路线是可行的。     

Determination of atrazine, desethyl atrazine and desisopropyl atrazine in environmental water samples using hollow fiber-protected liquid-phase microextraction and high performance liquid chromatography

A new method based on hollow fiber-protected liquid-phase microextraction (LPME) was developed for the simultaneous determination of atrazine, desethyl atrazine and desisopropyl atrazine in environmental water samples. In LPME, analytes were extracted into 1-octanol immobilized in the micropores of a poly(vinylidene fluoride) porous hollow fiber membrane, and back extracted into the acceptor (4 M HCl) filled in the lumen of the hollow fiber. After LPME, the analytes trapped in the acceptor were analyzed with high-performance liquid chromatography after neutralization. The effect of extraction factors such as sample pH, acceptor pH, salinity, extraction time, stirring rate, and humic acid were studied. Under the optimized conditions, the limits of detection and relative standard deviations were respectively in the range of 0.5–1.0 μg L⁻¹ and 3.9–4.7% (n = 5). The proposed method was applied to determine atrazine, desethyl atrazine and desisopropyl atrazine in wastewater and groundwater samples. The three analytes were below the limits of detection, but good relative spiked recoveries over 90.1 ± 5.9% at 5 μg L⁻¹ spiked level were obtained.     

Adsorption, desorption and activities of acid phosphatase on various colloidal particles from an Ultisol

Adsorption, desorption and activity of acid phosphatase on various soil colloidal particles and pure clay minerals were studied. Higher adsorption amounts and low percentage of desorption of acid phosphatase were found on fine soil clays (<0.2 μm). Electrostatic force and ligand exchange are the major driving forces that are involved in the adsorption of enzymes on soil clays. More enzyme molecules were adsorbed on soil clays in the presence of organic components. However, enzymes on organic clays were more easily released. One-third of the enzyme on goethite was adsorbed via ligand exchange process. Some other interactions, such as van der Waals force, hydrophobic force and hydrogen bonding may be more important in the adsorption of enzyme on kaolinite and the enzyme in this system cannot be easily removed. Coarse clays (0.2–2 μm) and inorganic soil clays had higher affinities for enzyme molecules than fine clays and organic clays, respectively. The activity of enzyme bound on soil clays was inhibited and the thermal stability was increased in the presence of organic matter. Data obtained in this study are helpful for a better understanding of the interactions of enzymes with inorganic and organic constituents in soil and associated environments.     

Coriatone and corianlactone, two novel sesquiterpenes from Coriaria nepalensis

Both coriatone (1). a novel highly oxygenated picrotoxane-type sesquiterpene, and corianlactone (2). with an unprecedented sesquiterpene basic skeleton, named coriane, were isolated from Coriaria nepalensis Wall. The structures of 1 and 2 were determined by analysis of their two-dimensional NMR data, and the structure of 2 was confirmed by X-ray analysis. Compounds 1 and 2 showed no remarkable inhibitory activity toward K(562) cells. They are cytotoxic with IC(50) > 50 microg/mL (cis-platinim: IC(50) = 0.49 microg/mL).     

双核银络合物[Ag_2(dppm)_2(Py)_2(μ-Cl)]ClO_4的合成与结构

二-(二苯基膦)甲烷(dppm)是一种易与金属形成多核络合物的有机膦配体。我们用dppm作为配体合成了一系列银的多核络合物,并对其结构进行了研究。本文报导了其中一个双核化合物[Ag_2(dppm)_2(Py)_2(μ-Cl)]ClO_4的合成及晶体结构、分子结构的测定。