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EFFECT OF chemical structure OF COMONOMERS ON THE PROPERTIES OF COPOLYESTERS

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Chinese Journal of Polymer Science 1997年第3期15卷 226-230页

作者：武荣瑞高谨李慧萍 Academy of Synthetic Fiber Beijing Institute of Clothing Technology Beijing 100029

The effect of different kinds of comonomers with or without flexible chain on properties of copolyesters, such as transition temperature, crystallization velocity, crystallinity and size Of crystallites, is studied. The experimental results indicate the obvious difference in properties between comonomers with iso-and ortho-structure of phenyl ring and comonomers with flexible chain. The influence of chemical structure of comonomers on properties of copolyesters is discussed.

关键词： copolyesters polyethyleneterephthalate comonomer chemical structure

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Spectroscopic Elucidation of the Links between Char Morphology and chemical structure of Coals of Different Ranks

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Advances in chemical Engineering and Science 2016年第4期6卷 379-398页

作者： Andrew O. Odeh Coal Research Group Unit of Energy Systems School of Chemical and Minerals Engineering North-West University Potchefstroom Campus Potchefstroom South Africa

In this investigation, SAXS and XRD were used to investigate both the physical and chemical changes in six coals of different ranks subjected to heat treatment. The specific surface area which gives an indication of the reactivity of the coal (measures surface area available for reaction) was determined to be in the range of 70.04 - 260.40 m2/cm3 particle volume for lignite from 450°C - 700°C. The specific surface area was determined to be in the range of 51.58 - 239.00 m2/cm3 particle volume for sub-bituminous;440.60 - 241.70 m2/cm3 particle volume for light volatile bituminous;452.71 - 247.73 m2/cm3 particle volume for high volatile bituminous;349.11 - 347.52 m2/cm3 particle volume for semi-anthracite and 333.60 - 125.34 m2/cm3 particle volume for anthracite respectively. On the other hand, the aromaticity was determined in the range of 0.66 - 0.76 for lignite;0.67 to 0.80 for sub-bituminous;0.91 - 0.97 for light volatile bituminous;0.93 - 0.99 for high volatile bituminous;0.96 - 1.00 for semi-anthracite and 0.96 to 0.99 for anthracite respectively. The porosity, pore size distribution associated with SAXS and the other crystallite parameters identified with XRD were also determined. Links between the physical and chemical parameters were established.

关键词： Coal Char Char Morphology chemical structure XRD SAXS

Isolation, Purification and chemical structure of a Pleurotus tuber-regium Proteoglycan

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食用菌学报 2006年第3期 66-69页

作者： WENG Bo-qi~ 1* , JIANG Zhi-he~ 2 , BIN Wen~ 3 , WANG Yi-xiang~ 1 , LUO Tao~ 2 , LIN Yong~ 2 ~ 1 Agricultural Ecology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350013, China ~ 2 Research Center of Edible Fungi Development and Application, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350013, China ~ 3 Department of Pharmaceutics, Shenyang Pharmaceutical University, Shenyang , Liaoning 110015, China

A proteoglycan with a molecular mass of 39810 as determined by gel filtration, was obtained from dry, powdered sclerotia of Pleurotus tuber-regium following extraction with water, ethanol precipitation, protein removal by the Sevage method, dialysis, and Sephadex G-75 chromatography. chemical analyses revealed the material to consist of 61.7% total sugar (calculated as glucose) and 38% nitrogen, and gas chromatography of acid-hydrolysis products indicated that the major monosaccharide components were glucose and galactose. Smith degradation data suggested that the main glycosidic linkage in the proteoglycan was β-1,4, and that β-1,3 linkages may also be present.

关键词： chemical structure Pleurotus tuber-regium Proteoglycan Sclerotia

chemical structure Changes and Correlation Analysis of High Density Polyethylene after Natural and Xenon Aging

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Chemical Structure Changes and Correlation Analysis of High ...

Facial amphiphilicity index correlating chemical structures with antimicrobial efficacy

2014中国功能材料科技与产业高层论坛

作者： Jun-jun GUO Hua YAN Zhi-de HU Jian-jian YANG Dept.of Chemistry ＆ Material Logistic Engineering University

Elucidation of the chemical structure changes that take place of high density polyethylene（HDPE）used as rotational packaging case by attenuated total reflection infrared spectroscopy（ATR-FTIR）,when natural aging ofLasa Tibet and xenon aging.The variations of carbonyl index（CI）,hydroxyl index（HI）,branching degree（N）and crystallinity（Xc）have been studied from qualitative and quantitative.Finally,the correlations between natural and xenon aging havebeen closely followed.It found that the oxidation and growth of unsaturated compounds play a leading role in the natural aging progress,but the polymeric chain scission is weak effect.However,the samples show a slower growth of unsaturated compounds and a sharp increase in polymeric chain scission after xenon aging.The CI,HI and N increased generally in a line fashion after natural and xenon aging while the Xc changes little.

关键词： Natural aging Xenon aging chemical structure Correlation ATR-FTIR

来源： cnki会议评论

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Bioactive Materials 2023年第2期20卷 519-527页

作者： Leman Buzoglu Kurnaz Yuanyuan Luo Xiaoming Yang Amjed Alabresm Ryan Leighton Rani Kumar JiHyeon Hwang Alan W.Decho Prakash Nagarkatti Mitzi Nagarkatti Chuanbing Tang Department of Chemistry and Biochemistry University of South CarolinaColumbiaSC29208United States Department of Pathology Microbiology and ImmunologyUniversity of South CarolinaSchool of MedicineColumbiaSC29209United States Department of Environmental Health Sciences University of South CarolinaColumbiaSC29208United States

Facial amphiphilicity is an extraordinary chemical structure feature of a variety of antimicrobial peptides and polymers.Vast efforts have been dedicated to small molecular,macromolecular and dendrimer-like systems to mimic this highly preferred structure or conformation,including local facial amphiphilicity and global amphiphilicity.This work conceptualizes Facial Amphiphilicity Index(FAI)as a numerical value to quantitatively characterize the measure of chemical compositions and structural features in dictating antimicrobial efficacy.FAI is a ratio of numbers of charges to rings,representing both compositions of hydrophilicity and hydrophobicity.Cationic derivatives of multicyclic compounds were evaluated as model systems for testing antimicrobial selectivity against Gram-negative and Gram-positive bacteria.Both monocyclic and bicyclic compounds are non-antimicrobial regardless of FAIs.Antimicrobial efficacy was observed with systems having larger cross-sectional areas including tricyclic abietic acid and tetracyclic bile acid.While low and high FAIs respectively lead to higher and lower antimicrobial efficacy,in consideration of cytotoxicity,the sweet spot is typically suited with intermediate FAIs for each specific system.This can be well explained by the synergistic hydrophobic-hydrophobic and electrostatic interactions with bacterial cell membranes and the difference between bacterial and mammalian cell membranes.The adoption of FAI would pave a new avenue toward the design of next-generation antimicrobial macromolecules and peptides.

关键词： Antimicrobial Facial amphiphilicity chemical structure Peptide

Directly imaging of the atomic structure of luminescent centers in CaYAlO_(4):Ce^(3+)

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Nano Research 2023年第2期16卷 3004-3009页

作者： Yalong Zhai Xuewei Yang Shu-Na Zhao Pei Liu Jun Lin Yang Zhang School of Materials Science and Engineering Center of Advanced Analysis&Gene SequencingZhengzhou UniversityZhengzhou 450001China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China DTU Nanolab.Technical University of Denmark Fysikvej2800 Kgs.LyngbyDenmark Green Catalysis Center and College of Chemistry Zhengzhou UniversityZhengzhou 450001China

Lanthanides(Ln^(3+))doped luminescent materials play critical roles in lighting and display techniques.While increasing experimental and theoretical research have been carried out on aluminate-based phosphors for white light-emitting diodes(WLEDs)over the past decades,most investigation was mainly focused on their luminescent properties;therefore,the local structure of the light emission center remains unclear.Especially,doping-induced local composition and structure modification around the luminescent centers have yet to be unveiled.In this study,we use advanced electron microscopy techniques including electron diffraction(ED),high-resolution transmission electron microscopy(HRTEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),in combination with energy dispersive X-ray spectroscopy(EDX)and electron energy loss spectroscopy(EELS),to reveal atomically resolved crystalline and chemical structure of Ce^(3+)doped CaYAlO4.The microscopic results prove substantial microstructural and compositional inhomogeneities in Ce^(3+)doped CaYAlO_(4),especially the appearance of Ce dopant clustering and Ce^(3+)/Ce^(4+)valence variation.Our research provides a new understanding the structure of Ln^(3+)doped luminescent materials and will facilitate the materials design for next-generation WLEDs luminescent materials.

关键词： luminescent white light-emitting diodes(WLEDs) rare earth element atomic structure chemical structure

Preparation and Properties of Chinese Lacquer Modified by Methylolureas

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Journal of Renewable Materials 2023年第2期11卷 1003-1016页

作者： Qiang Xiao Yanjun Cao Hailu Tan Qiaoling Feng Xinyue Gu Jianhua Lyu Hui Xiao Ming Chen Yuzhu Chen College of Forestry Sichuan Agricultural UniversityChengdu611130China Wood Industry and Furniture Engineering Key Laboratory of Sichuan Provinvial Department of Education Sichuan Agricultural UniversityChengdu611130China

In this study,different molar of methylolureas(MMU)were used to improve the properties and drying speed of the raw lacquer(RL).The drying time,gloss,pencil hardness and impact resistance of the lacquer film were tested.The thermal behaviors and chemical structures of the lacquer membrane were also discussed by thermal gravimetric analysis(TGA),fourier infrared spectrometer(FT-IR)and nuclear magnetic resonance(NMR)analysis,respectively.The results demonstrated that lower molar ratio MMU can significantly improve the properties of lacquer.The TGA analysis showed that the modified lacquer had high thermal stability than that of the control.The FT-IR and 13C NMR analysis revealed that the structures of the modified lacquer were significantly improved by cross-linking with the hydroxymethyl groups and methylene methyl ethers of MMU.In addition,through scanning electron microscopy(SEM)characterization,it was found that the introduction of MMU can effectively improve the surface smoothness of the lacquer film.

关键词： Raw lacquer methylolureas properties thermal behavior chemical structure

Natural product sciences: an integrative approach to the innovations of plant natural products

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Science China(Life Sciences) 2020年第11期63卷 1634-1650页

作者： Yuemao Shen Xiaojiang Hao Key Laboratory of chemical Biology of Natural Products School of Pharmaceutical SciencesShandong UniversityJinan 250012China State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China

The study on plant natural products not only helps us understand that their structural diversity is the inevitable result of plant species diversity, but also helps us understand certain rules and unity of the inevitable connection between the two. The diversity and complexity of chemical structures of many natural products are beyond imagination before we elucidated their structures.The question that follows is what is the biological significance of these natural products. Intrigued by the relationship between plant resources, natural products and biological functions, the Hao laboratory has taken an integrative approach that employs tools and knowledge from multi-disciplines, including natural product chemistry, chemical ecology and chemical biology, to unveil the effects of plant natural products on plant resistance to diseases, and environmental acclimations. Collaborating with cell biologists, the research has resulted in discovery of new mechanisms of cellular signaling and lead compounds.

关键词： plant natural product chemical structure biological significance

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Photochemistry and pharmacology of 9,19-cyclolanostane glycosides isolated from genus Cimicifuga

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Chinese Journal of Natural Medicines 2016年第10期14卷 721-731页

作者： SU Yang CHI Wen-Cheng WU Lun WANG Qiu-Hong KUANG Hai-Xue Department of Microbiology Immunology&Molecular GeneticsUniversity of California Los AngelesLos AngelesCA 90025USA Key Laboratory of Chinese Materia Medica Department of PharmacologyHeilongjiang University of Chinese MedicineHarbin 150040China The University of Sydney NSW 2006Australia

The constituents of Cimicifuga plants have been extensively investigated, and the principal metabolites are 9, 19-cyclolanostane triterpenoid glycosides, which often exhibit extensive pharmacological activities. 9, 19-Cyclolanostane triterpenoid glycosides are distributed widely in genus Cimicifuga rather than in other members of the Ranunculaceae family. So far, more than 140 cycloartane triterpene glycosides have been isolated from Cimicifuga spp.. The aim of this review was to summarize all 9, 19-cyclolanostane triterpenoid glycosides based on the available relevant scientific literatures from 2000 to 2014. Biological studies of cycloartane triterpene glycosides from Cimicifuga spp. are also discussed.

关键词： Cimicifuga spp 9,19-Cyclolanostane glycosides chemical structure Biological effects

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