4-(2-吡啶偶氮)间苯二酚盐酸盐的晶体结构

用SYNTEXP3/R3四圆衍射仪收集4-(2-吡啶偶氮)间苯二酚盐酸盐晶体的三维衍射数据。晶体属P2₁/c空间群,a=11.339Å,b=6.835Å,c=18.170Å,β=102.76°,Z=4。利用Patterson法及直接法测定了晶体结构。经位置坐标参数,各向异性温度因子及比例因子块矩阵最小二乘修正后,最后的R值为0.055。晶体结构分析结果表明:4-(2-吡啶偶氮)间苯二酚的分子内所有非氢原子共面并形成大的共轭体系。氯离子及二个结晶水与分子中的N,O形成氢键,起到桥联分子的作用。     

茜素红S与人血清白蛋白相互作用的分光光度研究

在ｐＨ４．３左右的Ｂｒｉｔｏｎ－Ｒｏｂｉｎｓｏｎ（Ｂ－Ｒ）缓冲溶液中,茜素红Ｓ（ＡＲＳ）与人血清白蛋白（ＨＳＡ）结合,生成红色的复合物,吸光度值与ＨＳＡ含量呈线性关系。复合物的吸收峰值λｍａｘ为５３０ｎｍ,比ＡＲＳ试剂本身红移１１０ｎｍ。其表观摩尔吸光系数ε＝１．０×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。ＨＳＡ标准曲线在其质量浓度１０～９００ｍｇ／Ｌ间呈线性关系,最低检出限为３ｍｇ／Ｌ。研究了该配合物用于蛋白质分光光度法测定的基本条件。应用该法测定了人血清样品,回收率在９６．９％～１０２．１％范围内。实验表明该反应选择性、重现性和对照性均好,操作简便,适用测定浓度范围宽     

空间材料抗原子氧有机涂层防护作用的光谱分析

用Fourier变换红外光谱(FTIR)、光电子能谱(XPS)和扫描电镜(SEM)对在模拟原子氧(AO)环境中,空间材料及在其表面涂覆的有机防护涂层的表面所发生的侵蚀与防护作用进行了研究。结果表明：采用环氧树脂、聚胺脂、醇酸树脂作为防护涂层,经AO辐照后,它们的表面形貌均发生了较大变化,腐蚀严重;而用有机硅涂层的表面形貌变化却甚小,具有较明显的防护效果。光谱分析表明,这种防护作用缘于有机硅涂层表面经AO辐照后生成了致密的氧化硅膜层,对抑制AO的进一步侵蚀起到了抑制作用。     

n阶微分方程三点边值问题

用上、下解方法讨论了非线性n阶常微分方程满足三点全非线性边界条件的边值问题解的存在性和唯一性。     

A new cycloartane nortriterpenoid from Quercus variabilis Blume

The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid,3α-acetyloxy-4α,14α-dimethyl-9β, 19-cycloergost-24-oic acid(1),along with five known compounds(2-6).The structure of 1 was elucidated by 1D and 2D NMR and mass spectroscopy.     

A novel cytotoxic neophysalin from Physalis alkekengi var.francheti

A new neophysalin,named 5α-hydroxy-25,27-dihydro-4,7-didehydro-7-deoxyneophysalin A(1),along with three other known neophysalins(2-4) were isolated from the calyxes of Physalis alkekengi L.var.francheti(Mast.) Makino.The structure of 1 was determined by means of 1D and 2D NMR,UV,IR and mass spectra.Compound 1 displayed potent cytotoxicities in vitro against PC- 3 and LNCaP cell lines.     

The chemical constituents of the tissue culture cells of Daphne giraldii cullus

Three compounds were isolated from the tissue culture cells of Daphne giraldii cullus,their structures were identified as daphneolone(1),S-(+)-1-(4-hydroxy-3-methoxyphenyl)-3-hydroxy-5-phenyl-1-pentanone(2),S-(+)-1-(4-methoxyphenyl)-3- hydroxy-5-phenyl-1-pentanone(3),and among them,2 was a new compound,3 was a novel natural product.     

A new protoberberine alkaloid from Corydalis yanhusuo W.T.Wang

A new protoberberine alkaloid,named 5,6-dihydro-10-hydroxy-2,3,9-trimethoxy-13-methyldibenzo[a,g]quinolizinium(1) was isolated from the 60%ethanol extract of the tubers of Corydalis yanhusuo W.T.Wang,together with a new natural product,13- methylpalmatrubine(2).Their structures were established by spectroscopic methods.     

Two new benzophenone glucosides from Cratoxylon cochinchinensis

Two new benzophenone glucosides were isolated from the 60%ethanol extract of the dried stems of Cratoxylum cochinchinense. The structures were elucidated as 3-O-β-D-glucopyranosyl-2′,4,6′-trihydroxy-benzophenone and 3-O-β-D-glucopyranosyl-2′,5,6′-trihydroxybenzophenone on the basis of spectral and chemical methods.     

改进可变区域拟合模型的合成孔径声呐图像分割方法

为了自动且高精度地分割合成孔径声呐图像中的目标和阴影区域,提出一种核函数尺度自适应可变区域拟合(RSF)模型的分割方法。使用一种基于K-均值聚类的自动初始化方法对水平集进行初始化,减少了人为干预;提出改进的核函数尺度自适应RSF模型,其利用声呐成像中目标与阴影在沿扫测方向具有近似宽度的一般规律,自适应选择核函数尺度参数,使得对应目标和阴影的水平集函数能够同步演化,提高最终分割精度。通过对真实声呐图像的实验结果分析,验证了该方法能较为准确地实现目标和阴影区域的分割,具有一定的精确性和适应性。