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1.
为建设高分子物理精品课程,近年来我们关注和跟踪高分子科学发展前沿,开设了"高分子材料流变学"、"高分子凝聚态物理"等新课,编著出版新教材。这些课程和教材的一个显著特点是不失时机地将学科发展的新动态、新成果引入研究生、本科生教学,提升高分子物理课教学质量。在编著新教材中,除介绍大量新知识、新思想外,还探索性地构建起新课程的理论体系和框架。  相似文献   

2.
新型四硫代富瓦烯衍生物的合成及其性质的研究   总被引:2,自引:0,他引:2  
合成了3个新的含有卤素取代基的四硫代富瓦烯衍生物及6个新的相关化合物。利用溶液的电子吸收光谱对四硫代富瓦烯衍生物的性质进行了研究。研究结果表明, 四硫代富瓦烯衍生物的分子中π轨道之间的能级差较小, 因而分子具有较高的稳定性。  相似文献   

3.
概念是有机合成化学发展的基础之一,新概念的产生和发展可为有机合成开拓新的研究领域和发展方向。此文介绍现代有机合成中的一些新概念和新方法,结合具体的有机合成反应实例展示有机合成在这些概念的基础上取得的新成果和新进展,并综合归纳了现代有机合成的发展方向和应重视的研究领域。  相似文献   

4.
中国番荔枝科植物抗癌有效成分研究   总被引:6,自引:0,他引:6  
陈若芸  于德泉 《有机化学》2001,21(11):1046-1050
介绍了近年来我们实验室中国番荔枝科植物抗癌有效成分研究工作。从番荔枝科5种紫玉盘属植物,5种哥纳香属植物,1种番荔枝属植物,1种囊瓣木属植物中分离得到59种新的番荔枝内酯,32种新的多氧取代环己烯,12种新的苯乙烯吡喃酮和3种新的生物碱,并通过化学和光谱方法鉴定了它们的结构。大部分化合物显示了较强的抗癌活性。并对抗癌活性成分海南哥纳香醇甲进行了全合成。  相似文献   

5.
In the context of formation of new aza analogs of camptothecin, nitration then reduction of condensed pyridones was realized, leading to new derivatives of pyrrolo-aza-indoles. Treatment of these compounds with hydrobromic acid led to new structure rearrangements while oxidation of the α-position was unsuccessful. Mechanisms of formation of the new products are discussed.  相似文献   

6.
A new three-parameter cubic equation of state is presented by combination of a modified attractive term and van der Waals repulsive expression. Also a new alpha function for the attractive parameter of the new EOS is proposed. The new coefficients of alpha function and the other parameters of the attractive term are adjusted using the data of the saturated vapor pressure and liquid density of almost 60 pure compounds including heavy hydrocarbons. The new EOS is adopted for prediction of the various thermophysical properties of pure compounds such as saturated and supercritical volume, enthalpy of vaporization, compressibility factor, heat capacity and sound velocity. Following successful application of the new EOS for the pure components, using vdW one-fluid mixing rules, the new EOSs are applied to prediction of the bubble pressure and vapor mole fraction of the several binary and ternary mixtures. The accuracy of the new EOS for phase equilibrium calculation is demonstrated by comparison of the results of the present EOSs with the PT, PR, GPR and SRK cubic EOSs.  相似文献   

7.
N-取代芳环-4-氨基喹唑啉类化合物的合成及生物活性研究   总被引:10,自引:0,他引:10  
刘刚  宋宝安  桑维钧  杨松  金林红  丁雄 《有机化学》2004,24(10):1296-1299
以4-氯喹唑啉和芳香胺反应,合成了三个新的N-取代苯环或杂环4-氨基喹唑啉类化合物.三个新化合物经1HNMR,IR及元素分析证明其结构.生物活性测试表明,三个新化合物均有一定的抑菌效果.  相似文献   

8.
According to Watson′s DSC principle, a new design of electric circuit of DSC was proposed, Referring to the instrument constraction of DSC of Perkin-Elmer corporation, a new instrument construction of DSC was designed.This new electric circuit and this new instrument construction can overcome the shortcomings in de- sign of DSC of Perkin-Elmer corporation, Figure 1 is a schematic diagram of the new electric circuit. The temperatures and enthalpies of phase transitions of stan- dard materials were measured by using the new DSC. The experimental results are shown in table 1.  相似文献   

9.
A new bicyclogermacrane sesquiterpenoid, two new cembrane diterpenoids and five new dolabellane diterpenoids, along with known terpenoids, have been isolated from the Malaysian liverwort Chandonanthus hirtellus. The structures of the new compounds were established by spectroscopic and chemical methods in addition to X-ray crystallographic studies.  相似文献   

10.
SummaryThethemeof 17ICCEisthatthenewcenturyoffersnewchallenges,newopportunitiesandnewhopesforchemicaledu cation .Theseaspirationsarecertainlycriticalforchemicaledu cationinAustralia ,particularlyatthetertiarylevel.Ithasbeenrecognizedforatleastthepasttwode…  相似文献   

11.
Water-soluble constituents of Glehnia littoralis fruit   总被引:2,自引:0,他引:2  
From the water-soluble portion of the methanol extract of the fruit of Glehnia littoralis Fr. SCHMIDT ex MIQ. (Umbelliferae; "hamabofu" in Japanese), thirty compounds, including three new monoterpenoids and a new monoterpenoid glucoside, a new benzofuran glucoside, a new alkyl glucoside, and a new glucide, were obtained. Their structures were clarified by spectral investigation.  相似文献   

12.
In this paper we present new modified open Newton Cotes integrators and we develop a new modified trigonometrically-fitted open Newton-Cotes method. We study the connection between the new proposed schemes, the differential methods and the symplectic integrators. although The research on multistep symplectic integrators is very poor, although, much research has been done on one step symplectic integrators and several of then have obtained based on symplectic geometry. In this paper a new open modified numerical algorithm of Newton-Cotes type is produced. We present the new obtained method as symplectic multilayer integrator. The new obtained symplectic schemes are applied for the solution of the resonance problem of the radial Schrödinger Equation. The results show the efficiency of the new proposed algorithm.  相似文献   

13.
In a survey the development of epoxy resin systems is described. During the past years countless formulations based on known structures were used, but only a relative small number of new epoxies and curing agents were investigated and only very few new compounds came on the market. A choice of these products will be discussed, also new latent accelerators and curing agents. By improvement of technical processes purer epoxies can be offered and toxicological risks could be strongly reduced. Especially new results in the fast growing field of photocrosslinking will be described. Besides iodonium, sulfonium and phosphonium compounds new arene iron salts and their behaviour will be presented. Generally, the trend in the epoxy field is to better heat resistant structures for new formulations in the field of adhesives and fibre-reinforced materials, and to new photocrosslinking systems.  相似文献   

14.
Density functional calculations were carried to improve the calculated CO vibrational frequencies for transition metal carbonyls. Two types of density functionals were studied, hybrid and generalized‐gradient methods. Using the simplex optimization method, new polarization functions for C and O atoms were obtained. With these new optimized functions, new scaling factors were obtained. The results reveal that, with the new polarization functions, the agreement between the calculated and the experimental values improves considerably. In general, the new scaling factors are very close to unit, with standard uncertainties close to ±0.006 cm?1. The use of the new polarization functions allows more precise calculations of the transition metal carbonyl CO vibrational frequencies. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008  相似文献   

15.
The present article starts with a short overview of the international development of the polyolefin production in the last 10 years and with a forecast for the next 3 to 5 years. The reason for these developments, as the cost/properties relationships will be discussed. The extended properties of the polypropylenes, their molecular and supermolecular structures, and the correlations to the properties play a central role in the paper. The reinforcing and compounding maximized the properties and reduced the weaknesses of the mechanical and thermal properties. The narrower molecular weight distribution and the possible new copolymers with better randomness and new comonomers explain the importance of the metallocene catalysts. Examples demonstrate the future developments of new PP's by orientation on a second generation of single site catalysts.

The super soft PIP's as a new interesting elastomer class, are described. The new developments from the post reactor modification to a new HMS-PP technology are described in detail. The new graft copolymers with styrene and methylmethacrylate are pointed.  相似文献   

16.
Short segments of zigzag single‐walled carbon nanotubes (SWCNTs) were obtained from a calixarene scaffold by using a completely new, simple and expedited strategy that allowed fine‐tuning of their diameters. This new approach also allows for functionalised short segments of zigzag SWCNTs to be obtained; a prerequisite towards their lengthening. These new SWCNT short segments/calixarene composites show interesting behaviour in solution. DFT analysis of these new compounds also suggests interesting photophysical behaviour. Along with the synthesis of various SWCNTs segments, this approach also constitutes a powerful tool for the construction of new, radially oriented π systems.  相似文献   

17.
Medicinal chemistry is facing new challenges in approaching precision medicine. Several powerful new tools or improvements of already used tools are now available to medicinal chemists to help in the process of drug discovery, from a hit molecule to a clinically used drug. Among the new tools, the possibility of considering folding intermediates or the catalytic process of a protein as a target for discovering new hits has emerged. In addition, machine learning is a new valuable approach helping medicinal chemists to discover new hits. Other abilities, ranging from the better understanding of the time evolution of biochemical processes to the comprehension of the biological meaning of the data originated from genetic analyses, are on their way to progress further in the drug discovery field toward improved patient care. In this sense, the new approaches to the delivery of drugs targeted to the central nervous system, together with the advancements in understanding the metabolic pathways for a growing number of drugs and relating them to the genetic characteristics of patients, constitute important progress in the field.  相似文献   

18.
杨啸涛  章诒学  汪雨 《分析化学》2011,(10):1517-1520
讨论了永久磁场塞曼背景校正原子吸收光谱仪的外光路和磁场的设计工艺,描述了可以同时获得交流磁场和直流磁场塞曼背景校正测定结果的新系统,以及可以克服洛伦兹力对测定产生影响的磁场和石墨炉的供电系统.  相似文献   

19.
李国胜  郑能武 《化学学报》1994,52(5):448-455
本文将价电子的轨道平均半径~n~l(n、l为轨道的主量子数和角量子数)引入电负性函数中,并采取与常规方法不同的方式确定有效核电荷数Z'。在此基础上,提出新的电负性标度-Z'/~n~l。该标度与Mulliken电负性有良好的线性关系,与Pauling电负性有大体上一致的周期性变化趋势。新标度有一定的物理含义,它代表价电子的平均核势,并且完全可由理论计算得到。  相似文献   

20.
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