检索结果-南通市图书馆

Chinese Chemical Letters 2013年第11期24卷 987-992页

作者： Shu Sun Jian-Bing Shi yu-ping dong Chen Lin Xiao-yu Hu Le-Yong Wang School of Materials Science and Engineering Beijing Institute of Technology Key Laboratory of Mesoscopic Chemistry of MOE Center for Multimolecular Chemistry School of Chemistry and Chemical Engineering Nanjing University

A pseudorotaxane and its polypseudorotaxanes formed between pillar[5]arene moieties and noctylpyrazinium cations as novel fluorescent sensors for the selective detection of halogen ions were reported.A collapse of these pillar[5]arene-based pseudorotaxanes and polypseudorotaxanes occurred upon the addition of Cl,Br,and I（tetrabutylammonium salts）,respectively,leading to their fluorescence *** fluorescence enhancement of the pseudorotaxane and the polypseudorotaxanes increases in the order of I

关键词： Pillararene Polypseudorotaxanes Fluorescent sensor Halogen ions detection

SYNTHESIS AND PHOTOLUMINESCENCE OF AN ANTHRACENE-CONTAINING HYPERBRANCHED POLY(ARYLENEETHYNYLENE)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2005年第6期23卷 665-669页

作者： Yong-qiang dong Zhen Li Jacky W. Y. Lam yu-ping dong Xin-de Feng Ben-zhong Tang Department of Polymer Science and Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 China Department of Chemistry Center for Display Research The Hong Kong University of Science ＆ Technology Clear Water Bay Kowloon Hong Kong China

A hyperbranched poly（aryleneethynylene） containing anthracene chromophore was synthesized by palladiumcatalyzed cross-coupling reaction of 2,4,6-triiodophenyl 9-anthracenylcarboxylate with 9,9-bis[4-（2-propynyloxy）phenyl]- 9H-fluorene. The structure and properties of the polymer are characterized and evaluated by NMR, IR, UV, PL and TGA analyses. The polymer is soluble in common organic solvents, possesses high thermal stability （Td 〉 330℃）, and emits a strong blue light of 465 nm in both solution and solid states.

关键词： Hyperbranched polymer Cross-coupling Blue light emission

Synthesis and Properties of Photodegradable Poly(furan-amine)s by a Catalyst-free Multicomponent Cyclopolymerization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2019年第10期37卷 981-989,I0004页

作者： Wei-Qiang Fu Gui-Nan Zhu Jian-Bing Shi Bin Tong Zheng-Xu Cai yu-ping dong Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science and EngineeringBeijing Institute of Technology

A series of new photodegradable poly(furan-amine)s(PFAs) were synthesized by a one-pot, catalyst-free, multicomponent cyclopolymerization between diisocyanides, dialkylacetylene dicarboxylates, and aromatic dialdehydes. All polymerizations were conducted in toluene at 100 ℃ for 6 h without inert gas protection and furnished polymers with a satisfactory molecular weight(Mw up to32200) and yield. The PFA structure was confirmed by spectroscopic techniques, such as GPC, FTIR, and NMR, as well as by comparison with a model compound. The polymers exhibited good solubility in common organic solvents and thermal stability. All the PFAs had high refractive indices in the visible light region(400 nm to 800 nm). Moreover, the PFAs were substantially degraded by UV irradiation due to the presence of furan rings. The film thickness reduction rate could be over 90%.

关键词： Photodegradation Multicomponent reaction Catalyst-free polymerization

Ds-echinoside A,a new triterpene glycoside derived from sea cucumber,exhibits antimetastatic activity via the inhibition of NF-κB-dependent MMP-9 and VEGF expressions

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第7期12卷 534-544页

作者： Qin ZHAO Zhi-dong LIU Yong XUE Jing-feng WANG Hui LI Qing-juan TANG yu-ming WANG ping dong Chang-hu XUE College of Food Science and Engineering Ocean University of China Qingdao 266003 China

Ds-echinoside A (DSEA),a non-sulfated triterpene glycoside,was isolated from the sea cucumber Pearsonothuria *** vitro and in vivo investigations were conducted on the effects of DSEA on tumor cell adhesion,migration,invasion,and *** this study,we found that DSEA inhibited the proliferation of human hepatocellular liver carcinoma cells Hep G2,with a half-maximal inhibitory concentration (IC50) of 2.65 μmol/L,and suppressed Hep G2 cell adhesion,migration,and invasion in a dose-dependent *** also reduced tube formation of human endothelial cells ECV-304 on matrigel in vitro and attenuated neovascularization in the chick embryo chorioallantoic membrane (CAM) assay in *** analysis revealed that DSEA significantly decreased the expression of matrix metalloproteinase-9 (MMP-9),which plays an important role in the degradation of basement membrane in tumor metastasis and *** also increased the protein expression level of tissue inhibitor of metalloproteinase-1 (TIMP-1),an important regulator of MMP-9 *** the results of Western blotting,the expressions of nuclear factor-kappa B (NF-κB) and vascular endothelial growth factor (VEGF) were found to be remarkably reduced by *** findings suggest that DSEA exhibits a significant antimetastatic activity through the specific inhibition of NF-κB-dependent MMP-9 and VEGF expressions.

关键词： Triterpene glycoside Ds-echinoside A (DSEA) Metastasis Angiogenesis Nuclear factor-κB (NF-κB) Matrix metalloproteinase-9 (MMP-9) Vascular endothelial growth factor (VEGF)

Catalyst-Free Four-Component Spiropolymerization for the Construction of Spirocopolymers with Tunable Photophysical Properties

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第10期41卷 1525-1532页

作者： Luo-Jie Zhu Gui-Nan Zhu Wen-Ya Yan Peng Sun Jian-Bing Shi Jun-Ge Zhi Bin Tong Zheng-Xu Cai yu-ping dong Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing100081China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing100081China Key Laboratory of Cluster Science of Ministry of Education School of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing100081China

Spiropolymers have gained a great deal of interest from both academic and industrial fields by virtue of their unique geometric structures and physical ***,we prepared a series of spirocopolymers through the catalyst-free four-component spiropolymerization of diisocyanides,activated alkynes,and two different kinds of monomers with reactive carbonyl *** is found that the polymerization reactivity of monomers,feeding modes,and feed ratios play significant roles in *** with high reactivity and feeding reactive monomers first contribute to improving the molecular weights and yields of the *** constructed copolymers have two different kinds of spiro structures,which is confirmed by the nuclear magnetic *** addition,the spirocopolymers display the unique cluster-triggered emission and aggregation-induced emission properties,and their emission properties can be well-modulated by altering the ratio of *** is highly anticipated that this line of research will enrich the methodology of multi-component spiropolymerization,and provide a new insight into developing spiropolymers with various spiro structures and tunable properties.

关键词： Multi-component spiropolymerization Spirocopolymers Aggregation-induced emissions Clusterization-triggered emissions

NITROXIDE-MEDIATED FREE RADICAL SYNTHESIS OF MESOGEN-JACKETED LIQUID CRYSTAL POLYMERS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 1999年第2期17卷 189-192页

作者： Xin-hua Wan Hui-lin Tu Ying-feng Tu dong Zhang Ling Sun Qi-feng Zhou yu-ping dong Mao Tang Department of Polymer Science & Engineering, College of Chemistry, Peking University, Beijing 100871, China Department of Materials & Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China Peking Univ Coll Chem Dept Polymer Sci & Engn Beijing 100871 Peoples R China Beijing Inst Technol Dept Chem & Mat Engn Beijing 100081 Peoples R China

The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.

关键词： TEMPO 'living' free radical polymerization mesogen-jacketed liquid crystal polymer mesophase polymerization

Tomato Root Response to Subsurface Drip Irrigation

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2004年第2期14卷 205-212页

作者： ZHUGEyu-ping ZHANGXu-dong ZHANGyu-Long LIJun YANGLi-Juan HUANGYi LIUMing-Da KeyLaboratoryofTerrestrialEcologicalProcess InstituteofAppliedEcologyChineseAcademyofSciencesShenyang110016（China）.E-mail：zgyp@*** LandandEnvironmentalCollege ShenyangAgriculturalUniversityShenyang110161（China）

Four depth treatments of subsurface drip irrigation pipes were designated as 1) at 20,2) 30 and 3) 40 cm depths all with a drip-proof flumes underneath,and 4) at 30 cm without a drip-proof flume to investigate the responses of a tomato root system to different technical parameters of subsurface drip irrigation in a glass greenhouse,to evaluate tomato growth as affected by subsurface drip irrigation,and to develop an integrated subsurface drip irrigation method for optimal tomato yield and water use in a glass greenhouse. Tomato seedlings were planted above the subsurface drip irrigation pipe. Most of the tomato roots in treatment 1 were found in the top 0-20 cm soil depth with weak root activity but with yield and water use efficiency (WUE) significantly less (P ---- 0.05) than treatment 2; root activity and tomato yield were significantly higher (P = 0.05) with treatment 3 compared to treatment 1; and with treatment 2 the tomato roots and shoots grew harmoniously with root activity,nutrient uptake,tomato yield and WUE significantly higher (P= 0.05) or as high as the other treatments. These findings suggested that subsurface drip irrigation with pipes at 30 cm depth with a drip-proof flume placed underneath was best for tomato production in greenhouses. In addition,the irrigation interval should be about 7-8 days and the irrigation rate should be set to 225 m3 ha-1 per event.

关键词： greenhouse root system response soil water subsurface drip irrigation

LINEAR AND HYPERBRANCHED POLYMERS WITH HIGH THERMAL STABILITY AND LUMINESCENCE EFFICIENCY

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2001年第6期19卷 585-590页

作者： Jacky Wing Yip Lam Jing-dong Luo Han Peng Zhi-liang Xie Kai-tian Xue yu-ping dong Lin Cheng Cheng-feng Qiu Hoi Sing Kwok Ben-zhong Tang Departments of Chemistry and Electrical & Electronic Engineering Hong Kong University of Science & Technology Clear Water Bay, Kowloon, Hong Kong China Hong Kong Univ Sci & Technol Dept Chem Kowloon Hong Kong Peoples R China Hong Kong Univ Sci & Technol Dept Elect & Elect Engn Kowloon Hong Kong Peoples R China

New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3 and 6 with 1-heptyne and 1-octyne have been achieved with WCl6- and TaCl5-Ph4Sn catalysts, respectively, giving soluble linear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2 x 10(5)) in high yields (up to 98%). The structures and properties of the polymers are characterized and evaluated by R NMR, TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stability and emit strong blue light upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL was observed in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has been achieved in 2, which are the best results for substituted polyacetylenes attainable so far.

关键词： disubstituted polyacetylene hyperbranched polyarylene light emission

在线全文

学校读者我要写书评

暂无评论

基于期权博弈的新产品项目战略投资决策

控制与决策 2007年第6期22卷 613-617页

作者：余冬平邱菀华北京航空航天大学经济管理学院北京100083

同时考虑企业投资的先动优势和后动优势,建立了新产品项目战略投资决策的期权博弈分析框架.研究了双头垄断企业最优均衡投资产量和最优投资时机决策,分析了其均衡战略投资策略规则及其条件,探讨了投资成本差异和市场不确定性程度对企业... 详细信息

同时考虑企业投资的先动优势和后动优势,建立了新产品项目战略投资决策的期权博弈分析框架.研究了双头垄断企业最优均衡投资产量和最优投资时机决策,分析了其均衡战略投资策略规则及其条件,探讨了投资成本差异和市场不确定性程度对企业价值和投资临界值的影响.最后通过数值释例对理论结果进行了验证.

关键词：实物期权双头垄断期权博弈先动优势后动优势

在线全文

学校读者我要写书评

暂无评论

基于竞争互动的实物期权均衡执行战略研究

系统工程理论与实践 2007年第5期27卷 12-21,28页

作者：余冬平中央财经大学国防经济与管理研究院北京100081

运用期权博弈方法,研究了成本不对称双头垄断企业战略投资决策问题.首先给出企业价值函数和投资临界值的显性表达式;分别针对正和负的外部性,对两企业实物期权均衡执行战略进行了深入研究,给出了均衡存在形式及其条件,以及各均衡最优投... 详细信息

运用期权博弈方法,研究了成本不对称双头垄断企业战略投资决策问题.首先给出企业价值函数和投资临界值的显性表达式;分别针对正和负的外部性,对两企业实物期权均衡执行战略进行了深入研究,给出了均衡存在形式及其条件,以及各均衡最优投资策略规则;并探讨了不确定对投资临界值,以及不确定、先动优势及后动优势对均衡形成和企业投资时间间隔的影响;最后,通过数值释例给出了几个最优投资策略的精练纳什均衡解.

关键词：竞争互动实物期权期权博弈双头垄断纳什均衡