海藻酸钠/大豆蛋白共混凝胶微球的结构

利用钙离子交联海藻酸钠／大豆分离蛋白共混溶液，制得海藻酸钠／大豆分离蛋共混凝胶微球．结果表明，海藻酸钠和大豆分离蛋白质量配比的不同以及各组分间相互作用的变化，微球呈现不同的微观结构．将微球干燥后置于水中溶胀，微球的尺寸无法回复到干燥前的尺寸，这是由于真空干燥处理使水分子挥发，促进微球内组分间形成了强的氢键作用所致．此外，用碱处理该共混微球，发现由于大豆分离蛋白溶解以及部分钙离子被置换析出，微球塌陷且内部形成了大孔．     

具有性质(G'_k)的Wakamatsu倾斜模

本文引进了具有性质(G'k)的Wakamatsu倾斜模的概念,并用同调有限子范畴的性质对其进行了刻画．     

橙皮素A的NMR研究

橙皮素A是从中药北沙参(Glehnia littoralis Fr. Schmidt ex Miquel)的正丁醇萃 取物中分离得到的一种8-O-4′-型异木脂素苷类化合物. 通过化学方法和波谱分析鉴 定了该 化合物的结构. 采用2D NMR技术对其NMR信号进行了全归属. DMSO-d₆代替CD₃OD作为溶剂，并利用重水交换，能准确读出偶合常数J_7,8值.      

北京自由电子激光最近进展──实现饱和振荡

北京自由电子激光(BFEL)装置于1993年底在10.68μm处实现了饱和振荡.输出激光能量为3mJ,饱和平顶宽度2μs.对应饱和振荡平均功率为210kW(宏脉冲),峰值功率约为20MW,比自发辐射高8个量级,单程小讯号净增益为24%,转换效率为0.45%,与理论预期结果相符.光束质量接近衍射极限.目前装置可工作于9-11μm.     

Possible triggering of solar activity to big earthquakes (Ms ≥ 8) in faults with near west-east strike in China

A big earthquake (Ms = 8.1) occurred at western Kunlun Mts gap on November 14, 2001. It is the biggest earthquake in China in the past 50 years and the only one with a magnitude bigger than 8 in China after Dangxiong Earthquake (M = 8) in Tibet in 1951. The big earthquake has drawn wide attention of scientists in seismological, geophysical, geological and astro-geodynamic circles. Scientists are interested in the occurrence regularity of the very big earthquakes and try to find out the fac…     

求解非对称线性方程组的QMRGCGS方法

1 引言 求解非对称线性方程组Ax=b的双共轭梯度方法(BCG)[3]和它的变形共轭梯度平方方法(CGS)[6]都有典型的不规则收敛行为,后来Freund和Nachtigal提出一种BCG类方法,即拟极小剩余方法(QMR)[7],用来补救BCG方法的收敛性并且产生了光滑的收敛曲线。然而,象BCG方法一样,QMR方法要用到系数矩阵A及其转置A~T与向量的乘积,为了解决这一问题,Freund提出TFQMR方法,此方法具有拟极小剩余性,同时不需用到A~T与向量的乘积。     

Effect of a low magnetic field on crystallinity and magnetic susceptibility of molecular magnet {NBu4[FeCr(ox)3]}x (NBu4=tetra( n-butyl) ammonium ion; ox=oxalate ion)

Molecular magnet {NBu₄[Fe Cr(ox)₃]}_x (NBu₄⁺=tetra(n-buty1) ammonium ion; ox²⁻=oxalate ion) was synthesized under an applied low magnetic field of 0.3 T in comparison to that synthesized without a field. Their crystallinities, morphologies and magnetic properties were characterized by using the X-ray diffractionmeter, the transmission electron microscope, and a superconducting quantum interference device. It is found that the average size of particles synthesized under the applied field appears larger than that synthesized without a field. Moreover, its crystallinity, morphology and magnetic susceptibility have also been improved. However, its chemical structure and ferromagnetic phase transition temperature T_c do not change. Possible reasons to explain this effect are also discussed.