A new cytotoxic cardenolide from the latex of Antiaris toxicaria

A new cardenolide,toxicarioside E(1),was isolated from the latex ofAntiaris toxicaria(Pers.) Lesch(Moraceae).Its structure was elucidated on the basis of spectral data and chemical evidence.Compound 1 showed significant cytotoxicity against K562 and SGC-7901 cell lines in vitro by MTT method with the IC_(50) value of 0.026 and 0.027μg/mL,respectively.     

Measurement of Atrazine Adsorption onto Surficial Sediments (Natural Surface Coatings)——New Evidence for the Importance of Fe Oxides

To reveal the relative contribution of the components, Fe, Mn oxides or organic materials(OMs) in the surficial sediments(SSs), and the natural surface coating samples(NSCSs) to adsorbing atrazine(AT), a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting(NLSF) to estimate the relative contribution of the com-ponents. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, be-fore and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs(NSCSs) facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs(NSCSs) particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar ba-sis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in con-trolling the environmental behavior of AT in an aquatic environment.     

一种新型直流混合型HTSCFCL的研究

在研究混合型高温超导限流器和失超桥式整流型高温超导限流器原理的基础上,提出了一种新型单相混合型高温超导限流器,利用MATLAB进行仿真研究,结果表明该限流器设计参数准确,限流效果明显.新型直流混合型HTSCFCL的研究对限制短路电流和提高系统稳定运行具有十分重要的意义.     

ICP—AES同时测定植物中十八种元素的方法研究（干灰化法）

本文应用电感耦合等离子体光谱法(简称 ICP-AES)同时测定植物中十八种元素。用干灰化法制备待测液。选用了仪器最佳折衷条件。并采用了干扰等效浓度消除光谱干扰。本法的准确度与精密度均达到满意的结果。方法简便、快速。     

泡塑富集发射光谱法连测化探样品中超痕量金、铂、钯

为实现化探方法直接寻找贵金属金、铂、钯。需要一种操作简便、检出限低、对设备无特殊要求的分析方法。本文研究了泡塑富集发射光谱法连测化样品超痕量金、铂钯的方法。方法用于贵州省二级标准样的测定,结果与推荐值相符。     

一种亲水的酚羟基修饰聚苯乙烯树脂对酚类化合物的吸附热力学

在283-323K和研究的浓度范围内,苯酚、对甲苯酚、对氯苯酚和对硝基苯酚在亲水性的酚羟基修饰聚苯乙烯树脂（AM-1）与大孔吸附树脂（Amberlite XAD-4)上平衡吸附数据符合Freundlich吸附等温方程。酚类化合物在AM-1上的吸附容量比在Amberlite XAD-4上的吸附容量增加20%以上,这主要得益于AM-1表面的酚羟基入树脂的微孔结构。在较稀的溶液中AM-1对苯酚的吸附量比AmberliteXAD-4对苯酚的吸附量增加60%,表明AM-1对苯酚有特殊的选择性。Freundlich吸附等温线、相对吸附容量以及等量吸附焓表明,四种酚在两种树脂上的吸附是物理吸附过程。对酚类化合物被两种树脂吸附的吸附焓、自由能、吸附熵也作了测试,并对吸附行为作了合理的解释。     

聚合硅酸硫酸铁和聚合硫酸铁处理黄河水的效果及其絮体特性研究

采用聚合硅酸硫酸铁(PFSS)和聚合硫酸铁(PFS)两种无机高分子混凝剂处理黄河水,考察了两种混凝剂对浊度和UV254的去除效果,并结合混凝过程中絮体zeta电位的变化,分析了两种混凝剂的混凝机理.通过激光粒度仪在线观察混凝过程中絮体的生长情况,发现PFSS比PFS生成的絮体生长速度快,尺寸大.对形成的絮体施加不同强度的剪切力,通过观察絮体粒径的变化来比较絮体的强度,发现PFSS生成的絮体强度较大.研究了在不同剪切强度和不同剪切时间下絮体的破碎程度和絮体的恢复能力(分别以破碎因子Bf和恢复因子Rf表示),发现在强剪切力和长剪切时间下Bf和Rf均较大;在相同条件下PFSS生成絮体的Bf较小而PFS生成絮体的Rf较大,这表明前者的抗剪切能力较强,而后者具有更强的再生能力.     

Electrocatalytic activity of non-precious metal catalyst Co-N/C toward oxygen reduction reaction

<正>Metallic cobalt was deposited on acetylene black to synthesize a composite Co/C by chemical reduction method.A platinumfree electrocatalyst Co-N/C(800) for oxygen reduction reaction(ORR) was synthesized by mixing the composite Co/C with urea and heat-treating at 800℃.The results from linear sweep voltammograms indicated that the Co-N/C(800) is active to ORR.Theβ-Co and cobalt oxides are not the active site of the catalyst Co-N/C.However,the existence of cobalt facilitated the modification of nitrogen to carbon black and led to the formation of active site of catalyst Co-N/C(800).     

改进桥路型高温超导限流器的实验研究

本文介绍了单相基本桥型高温超导限流器的基本工作原理,及其参数变化对限流特性的影响.在此基础上研究应用于电力系统中的改进桥路型高温超导故障限流器实验室样机,正常工作情况,在电桥上引入直流偏置电流,不出现限流现象;短路故障情况,整流桥中的直流偏流影响限流效果,在桥路上引入限流电阻,使故障电流限制到预定的范围.研究了该限流器的工作原理,分析限流参数的变化对其限流特性的影响.实验表明,该限流器有很好的限流和重合闸能力,能显著减少暂态及稳态的故障电流。