离子色谱测定土壤中Cl~-和SO_4~(2-)

介绍了离子色谱法测定土壤中Cl-和SO24-的可行性以及相关的前处理方法,通过一定前处理方法,减少土壤中杂质对测定的干扰和对色谱柱的污染。有效选取提取液的种类和浓度及提取时间,准确测定了土壤中Cl-和SO42-含量。Cl-和SO42-的相对标准偏差分别为2.70%、2.89%,检出限分别为0.1950、0.2230μg.mL-1,平均回收率分别为106.7%,95.8%。方法简便,快速、灵敏度高。     

具交叉感染的流行病模型的数学分析

In this paper,an initial boundary value problem with homogeneous Neumann boundary condition is studied for a reaction-diffusion system which models the spread of infectious diseases within two population groups by means of self and criss-cross infection mechanism. Existence,uniqueness and boundedness of the nonnegative global solution (u1,u2,u3,u4),existence of the limit of the solution as t→+∞,namely,(u1,u2,u3,u4)→(u*1,0,u*3,0),are proved.     

光学相干层析成像系统的实验研究

介绍了作者研究建立的光学相干层析（ＯＣＴ）成像系统,给出了利用该系统得以的实际生物样品光学相干层析图像,并对系统性能和结果作了分析,讨论了影响系统性能的一些因素及改进方法。     

激光相干层析成像的光散射模拟计算

利用低相干光作为光源的光学相干层析技术是一种新型成像技术。本文利用蒙特－卡罗（Ｍｏｎｔｅ－Ｃａｒｌｏ）模拟计算方法研究了该技术在不同的散射条件下,相干调制信号随散射系数的变化关系,得出了单次散射和多次散射的差别以及它对成像质量的影响,并进一步讨论了利用单次散射和多次散射信号,提高光学相干层析术图像清晰度和信号强度的方法。还研究了光束半径大小对成像分辨率的影响及变化过程,得出了对实验有指导意义的结果     

H2S·HOH or H2O·HSH, which is more stable in the water-hydrogen sulfide complex?

High-level ab initio calculations are carried out to study the relative stability of the two hydrogen bonded structures of water-hydrogen sulfide complex, one with water as the proton donor (A) and the other with hydrogen sulfide as the proton donor (B). The results show that structure A is considerably more stable than B at the correlated level, which is in contrast with previous results obtained from Hartree-Fock calculations.     

Flavonoids from the leaves of Epimedium Koreanum Nakai and their potential cytotoxic activities

Abstract

Phytochemical studies on the leaves of Epimedium koreanum Nakai have resulted in the discovery of two new flavonol glycosides, koreanoside F (1) and koreanoside G (2), along with six known flavonoids. Their structures were elucidated on the basis of HRESIMS, UV, IR, 1?D NMR and 2?D NMR data. Absolute configurations of 1 and 2 was further determined by ¹³C-NMR spectra with gate decoupling (GD). All of the compounds were evaluated for cytotoxic activities by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay. The results indicated that compounds 3, 5, 6, 7 and 8 inhibited the proliferation of A549 and NCI-292 cells with IC₅₀ values of 5.7–23.5?μM. Real-time monitoring in three kinds of lung cancer cells and a kind of human bronchial epithelial cells treated with compound 6 was also assessed.