云南红豆杉内生真菌次生代谢产物抗菌活性的研究

从红豆杉树皮中分离得到一株产紫杉醇或紫杉烷类化合物的内生真菌,分别用三氯甲烷、乙酸乙酯对其次生代谢产物进行提取,以白色念珠菌、枯草芽孢杆菌、金黄色葡萄球菌、绿脓杆菌、大肠杆菌作为指示菌株,对提取液的抑菌活性进行了检测。结果显示:目标菌株次生代谢产物的两种提取物对五种致病菌都有一定的抑制效果,且胞外提取物的抑菌活力均比胞内提取物的抑菌活力大;三氯甲烷提取物的抑菌活性强于乙酸乙酯提取物的抑菌活性;其中三氯甲烷胞外提取物对金黄色葡萄球和白色念珠菌菌表现出非常强烈的抑菌效果。     

山蒟(Piper hancei Maxim)杀虫活性初步研究

[目的]研究山蒟的杀虫活性,以丰富植物源农药的来源.[方法]采用胃毒法测定山蒟对家蝇的胃毒活性,浸渍法测定山蒟对致倦库蚊和白纹伊蚊的活性.[结果]结果显示:山药的石油醚萃取物表现较强的杀虫活性,石油醚提取物1 g/L处理家蝇12、24 h后,校正死亡率分别为86.66％、90％,处理家蝇12、24、36 h后的LC50值分别为1.4000、0.5000、0.2000 g/L,接近于处理36h后鱼藤酮的LC50值(0.08 g/L).石油醚提取物处理致倦库蚊和白纹伊蚊12h后的LC50值分别为2.4127、10.5163 mg/L,活性分别高于对照药物鱼藤酮的3.1727、21.5100 mg/L.[结论]山蒟具有较好杀虫活性,经检索未见相关文献曾报道山药的杀虫活性.     

孜然在农业植物病原真菌上的抑菌活性研究

以小麦赤霉病菌、玉米大斑病菌、辣椒疫霉病菌、苹果炭疽病菌、番茄灰霉病菌为供试菌种,对孜然的茎干、种子及种子的不同溶剂提取物进行了抑菌活性测定,结果表明,孜然(Cumlnum.cyminum)种子对菌丝的抑菌活性高,且其乙酸乙酯提取物的抑菌活性高于其它5种溶剂提取物,对辣椒疫霉病菌菌丝的EC50最小,为6.1335g/L。     

地肤子抑菌活性成分筛选

以最小抑菌浓度为指标,采用二倍稀释法分别测试地肤子乙醇提取物中的石油醚相、乙酸乙酯相、正丁醇相和水相萃取物对4株细菌和5株植物病原菌的抑制作用;再对抑菌活性较强的萃取物进行分离纯化,通过二倍稀释法测试所分离化合物的抑菌活性,并对其结构进行表征。结果表明,正丁醇相萃取物的抑菌活性最强,从中分离得到3个化合物,其中化合物Ⅰ的抑菌活性较强,对大肠杆菌具有显著的抑制作用,其最小抑菌浓度为31.3μg·mL-1,经1 HNMR、IR及高分辨质谱等鉴定化合物Ⅰ为齐墩果酸。齐墩果酸有较强的抑菌活性,是地肤子抑菌活性的物质基础。     

竹叶黄酮提取物的抑菌活性研究

采用稀释法研究了竹叶黄酮提取物的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）,并采用滤纸片法对竹叶黄酮提取物及其水解产物的抑菌活性进行了对比研究。试验结果表明竹叶黄酮提取物对藤黄微球菌、沙门氏菌、马红球菌、痢疾志贺氏菌、柠檬酸杆菌的抑菌效果及杀菌效果较好,其中竹叶黄酮提取物水解产物对藤黄微球菌的抑菌杀菌效果尤为明显,...     

三桠苦提取物抑菌活性研究

目的：研究三桠苦提取物的抑菌活性。方法：以95%乙醇为溶剂,分别利用超声波提取和回流提取方法获得三桠苦提取物,利用滤纸片扩散法,分析两种提取方法的提取物对大肠杆菌、金黄色葡萄球菌、枯草杆菌和沙门氏菌的抑菌活性差异,确定抑菌活性较好的提取方法。利用该方法提取三桠苦得到提取物,采用溶剂萃取法,依次用石油醚、二氯甲烷、乙酸乙酯和正丁醇分别萃取三桠苦提取物,得到极性大小不同的萃取物,再次利用滤纸片扩散法,比较这些萃取物对四种菌的抑菌活性,确定三桠苦的抑菌活性部位,为三桠苦抑菌活性成分的深入研究提供参考。结果：回流提取法获得的样品抑菌活性优于超声提取法;石油醚、二氯甲烷萃取物表现出较好的抑菌活性,乙酸乙酯萃取物抑菌活性较差、正丁醇萃取物无抑菌活性。结论：三桠苦提取物具有抑菌活性,其二氯甲烷萃取物是具有较强抑菌作用的活性部位。     

吴茱萸柠檬苦素提取物的抑菌效果研究

采用稀释法研究了吴茱萸柠檬苦素提取物的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）,并采用滤纸片法对吴茱萸柠檬苦素提取物和吴茱萸的醇提物的抑菌活性进行了对比研究。试验结果表明吴茱萸柠檬苦素提取物对藤黄微球菌、沙门氏菌、痢疾志贺氏菌、柠檬酸杆菌的抑菌效果及杀菌效果较好,其中吴茱萸柠檬苦素提取物的抑菌杀菌效果明显高于同浓...     

火炭母提取物抑菌活性的初步研究

对药用植物火炭母（Polygonum chinense Linn.）提取物的抑菌活性进行了研究。结果表明：（1）不同部位提取物中,叶和茎均含有抑菌活性物质,但叶提取物的抑菌效果更强、更明显;（2）不同溶剂提取物中,65%乙醇提取物具有最佳抑菌效果;（3）不同提取方法提取物中,超声提取物抑菌效果较索氏提取物抑菌效果强,但差异不是很大;（4）不同溶剂萃取物的抑菌实验表明,火炭母提取物中的抑菌活性物质易溶于乙醚、石油醚等非极性溶剂;（5）火炭母提取物对金黄色葡萄球菌、痢疾杆菌、枯草杆菌、藤黄球菌、白色念珠菌的最小抑菌浓度（MIC）分别为0.6g.mL-1、0.6g.mL-1、0.8g.mL-1、1.0g.mL-1、0.6g.mL-1,最小杀菌浓度（MBC）均为1.0g.mL-1。为开发新型、安全、高效的临床药物及扩大药源提供了科学依据。     

藓类提取物对白菜软腐病菌的抑菌活性

以欧文氏菌（Erwinia carotovora）为供试菌,对24种藓类乙醇提取物进行抑菌活性筛选。结果表明,有15种藓类提取物对欧文氏菌表现出不同程度抑菌作用,并将有较强抑菌作用的提取物对欧文氏菌进行了最低抑菌浓度MIC测定。     

无患子提取液制备纳米银及其协同抗菌性研究

以无患子提取液为还原剂,制备了含有纳米银的无患子复合抗菌液,考察了无患子提取液用量、温度、硝酸银摩尔浓度等因素对纳米银形貌和粒径的影响,并借助UV-Vis可见分光光谱、X射线衍射(XRD)以及透射电子显微镜(TEM)对产物进行表征;通过抑菌环法探讨了复合抗菌液对大肠杆菌的抗菌活性。由UV-Vis图谱可知,复合抗菌液等离子体共振吸收峰(SPR)在418 nm左右,说明该复合抗菌液中有纳米银的存在;XRD图表明合成的纳米银为面心立方结构;TEM图表明合成纳米银粒径为10~40 nm。由此获得的含有纳米银的无患子复合抗菌液对大肠杆菌表现出显著协同抗菌活性,抑菌圈直径变大。     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.     

泡沫起泡性、稳定性及评价方法

本文论述了泡沫的两个基本性质:起泡性和稳定性。对起泡性和提高泡沫稳定性的方法作了评价。