Synthesis and Crystal Structure of Ethyl 2,7,7-Trimethyl-4-(4''''-methylphenyl)- 5-oxo-1,4,5,6,7,8-hexahydroquinoline-3- carboxylate in Aqueous Medium

1 INTRODUCTION The 1,4-dihydropyridines (1,4-DHPs) are biologi- cally interesting compounds and have been developed extensively in pharmacology. 1,4-DHP derivatives are used therapeutically in the treatment of cardio- vascular disorders, especially hypertension and coro- nary heart disease such as angina pectoris, atheros- clerosis, etc. The DHPs have emerged as one of the most important classes of drugs for the treatment of gastrointestinal disease, Raynaud?s disease, pulmonary hyper…     

Synthesis and Crystal Structure of N, N'''''''',N''''''''-Tris-(2-oxynaphthalidene)-tris-(2-iminoethyl) Amine

1 INTRODUCTION Schiff’s bases are well known ligands representedby many bi-, tri-, tetra-, and hexa-dentate example-es[1], but heptadentate ligands are relatively rare[2, . 3]We have reported a copper complex of tetradentateSchiff’s bases[4]…     

混沌吸引子在两个周期振子耦合下的相同步

在分析了系统稳定的基础上，对非线性混沌吸引子在两个独立外周期振子耦合下的相同步进 行了研究.与一个周期振子耦合的情况不同，两个周期振子对混沌吸引子的耦合具有排他性 和竞争性，相同步在两个亚稳态交替出现，各自同步时间长度由外振子参数决定.确定了周 期外振子参数与同步时间长度的关系并与数值模拟计算结果进行了比较. 关键词： 混沌吸引子 相同步     

等离子体成像的初步诊断结果

HL-2A装置的主要目标是开展高参数条件下改善等离子体约束实验，研究剖面控制和建立先进约束位形。在偏滤器物理方面，研究等离子体粒子与能量控制、边界输运及刮削层物理机制，此外也可以进行二级加热和电流驱动。     

Structure of Cytochromec and Its Platinum-modified Derivatives by Fourier Transform Infrared Spectroscopy

ＳｔｒｕｃｔｕｒｅｏｆＣｙｔｏｃｈｒｏｍｅｃａｎｄＩｔｓＰｌａｔｉｎｕｍ┐ｍｏｄｉｆｉｅｄＤｅｒｉｖａｔｉｖｅｓｂｙＦｏｕｒｉｅｒＴｒａｎｓｆｏｒｍＩｎｆｒａｒｅｄＳｐｅｃｔｒｏｓｃｏｐｙＪＩＡＮＧＬｉ－ｊｕａｎａ，ＳＵＮＷｅｉ－ｙｉｎａ，ＦＡＮＧＪ...     

煤中氢键类型的研究煤中氢键类型的研究

采用真空红外光谱技术清晰地观察到了碳含量７３～８８ｗ％（ｄａｆ）的四个煤样及其溶剂抽出物中的五种羟基的不同氢键缔合类型，并通过原位热解红外光谱技术研究了它们的热稳定性。结果表明，它们的热稳定性顺序为：ＯＨ…π＜ＯＨ…Ｎ＜ＯＨ自缔合≈环状四聚体ＯＨ＜ＯＨ…醚氧。     

布朗运动实验的改进

1溶液配制的改进（1）挤出一点儿橙黄色的油彩（学生绘画用），加水，搅拌，直到观察到稍显混浊状．（2）用胶头滴管滴墨汁两到三滴于小烧杯中，加清水（最好蒸馏水）15—20ml，搅拌．（3）将稀释后的墨汁用胶头滴管吸2—3滴滴于油彩溶液中，搅拌匀．（4）通过滤纸过滤后滴入载     

On the Nonexistence of Laurent Polynomial First Integrals for General Nonlinear Systems

The integrability of a system of ODEs 圣=/(x1is defined as the existence of a sufficiently rich set of first integrals such that its solutions canbe expressed by these integrals.Here,a single-valued function西(。)is called a first integralof the system(1)if it is constant along any solution curve of the system(1).If≯(z)isdifferentiable,then this definition can be written as the condition (筹川瑚=0.The singularity analysis has been proved to be a successful tool for finding integrable systems…     

有机掺杂溶胶-凝胶法制备pH敏感膜及其光谱响应的研究

使用四甲氧基硅烷（TMOS）和二甲基二甲氧基硅烷（DiMe-DMOS)为共先驱体，采用溶胶－凝胶的有机掺杂，制备对pH具有宽程响应的敏感膜。详细考察了包埋溴酚蓝和溴酚绿的敏感膜对pH的响应值、响应时间、泄漏和可逆性等响应性能指标，并进行了溴酚蓝和溴酚绿在水相与膜内吸收光谱的研究。     

Synthesis and Crystal Structure of the Heteropolymate Compound Na_3H_2[Ce_3(H_2O)_(18)Bi_2W_(22)O_(76)]·23H_2O

1 INTRODUCTION As a rich remarkable class of inorganic cluster systems, polyoxometalates continue to be the focus of significant attention in the 21th century because of their various and alluring topologies as well as their unusual physicochemical prope…