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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 ...

Correlation between chemical structure and Biological Activity of Host-Selective Plant Pathogen Mycotoxins

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 *** variations of carbonyl index（CI）,hydroxyl index（HI）,branching degree（N）and crystallinity（Xc）have been studied from qualitative and ***,the correlations between natural and xenon aging havebeen closely *** 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 ***,the samples show a slower growth of unsaturated compounds and a sharp increase in polymeric chain scission after xenon *** 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

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Chinese Forestry Science and Technology 2007年第1期6卷 62-68页

作者： WEI Shuhua LIANG Jun WE Jianren ZHANG Xingyao School of Resources and Environment of Nanjing Forestry University Nanjing 210037 P.R. China Institute of Forest Ecology Environmental and Protection Chinese Academy of Forestry Beijing 100091. P.R. China

Toxin, one of the most important factors of plant fungal disease, has attracted much attention of many academicians who have been studying pathogen mycotoxin in deep research. The paper summarized chemical structures of some host-selective plant pathogen mycotoxins discovered in recent years and the correlation between biological activity and chemical structure of toxin.

关键词： plant pathogen fungi host-selective toxin chemical structure biological activity

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

Facial amphiphilicity index correlating chemical structures with antimicrobial efficacy

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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 *** 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 *** work conceptualizes Facial Amphiphilicity Index(FAI)as a numerical value to quantitatively characterize the measure of chemical compositions and structural features in dictating antimicrobial *** is a ratio of numbers of charges to rings,representing both compositions of hydrophilicity and *** derivatives of multicyclic compounds were evaluated as model systems for testing antimicrobial selectivity against Gram-negative and Gram-positive *** monocyclic and bicyclic compounds are non-antimicrobial regardless of *** efficacy was observed with systems having larger cross-sectional areas including tricyclic abietic acid and tetracyclic bile *** 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 *** can be well explained by the synergistic hydrophobic-hydrophobic and electrostatic interactions with bacterial cell membranes and the difference between bacterial and mammalian cell *** 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

Effects of microstructural evolutions of pyrolysis char and pulverized coal on kinetic parameters during combustion

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Journal of Iron and Steel Research International 2019年第12期26卷 1273-1284页

作者： Jiang-yong He Chong Zou Jun-xue Zhao Cheng Ma Xiao-rui Zhang School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710311ShaanxiChina

Pyrolysis chars have potential as fuels for pulverized coal injection(PCI);however,their proper and efficient utilization requires evaluation of char combustion *** combustion characteristics of two chars(F-char and M-char)and two pulverized coals(H-PCI and P-PCI)were analyzed herein using thermogravimetric analysis–mass *** apparent activation energy(Ea)of the sample under non-isothermal combustion conditions was obtained using the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods,and the reaction mechanism for the fuels was established using the Malek ***,changes in the microscopic pore structure and carbon chemical structure of the fuels at different stages of combustion were characterized using N2 adsorption and X-ray diffraction to analyze the relationship between microstructural evolution and *** results suggested that Ea of the sample first rapidly decreased and then became stabilized during *** with pulverized coals,the two chars presented more developed micro-scopic pore structure,less-ordered carbon chemical structure and lower Ea during *** combustion,the stacking height of the aromatic layer first decreased and then increased,whereas the specific surface area first increased and then *** volatile content significantly influenced Ea only during the initial stage of *** the middle stage,Ea was controlled more by the microscopic pore structure and the carbon chemical structure,and those influences disappeared in the later *** transition point of the structures affecting Ea occurred at a combustion rate between 52.9%and 72.0%.In general,the microscopic pore structure and the carbon chemical structure influenced kinetic parameters more than the volatile content.

关键词： Char Pulverized coal Combustion chemical structure Kinetics Activation energy Pore structure

PREPARATION AND structure OF FIVE DERIVATIVES OF β-(1→3)-D-GLUCAN ISOLATED FROM PORIA COCOS SCLEROTIUM

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Chinese Journal of Polymer Science 2004年第2期22卷 137-145页

作者：张俐娜 Department of Chemistry Wuhan University Wuhan 430072 China

A new solvent of cellulose (1.5 mol/L NaOH/0.5 mol/L urea aqueous solution) was used as one of the homogeneous reaction media of polysaccharides for methylation, hydroxyethylation and hydroxypropylation. A water insoluble β -(1—>3)-D-glucan, sample PCS3- isolated from fresh sclerotium of Poria cocos was sulfated in dimethyl sulfoxide (Me 2 SO), carboxymethylated in NaOH, isopropanol solution, as well as methylated, hydroxyethylated and hydroxypropylated in the new solvent system, respectively, to obtain five water-soluble derivatives coded as S-PCS3- C- PCS3- M-PCS3- HE-PCS3- and HP-PCS3- Their chemical structure and distribution of substitution were characterized by infrared spectroscopy (IR), elementary analysis (EA), 1 H-NMR, 13 C-NMR, 2D-COSY, 2D-TOCSY and 2D- 1 H-detected 1H 13C HMQC spectra. The results reveal that the relative reactivity of hydroxyl groups of the β -(1-?3)-D-glucan is in the order C-6 > C-4 > C-2 on the whole. The substitution of the samples S-PCS3- C-PCS3- and M-PCS3- occurred mainly at C-6 position and secondly at C-4 and C-2 positions, and that of HE-PCS3- occurred at C-6 and C-4 positions and of HP-PCS3- almost completely occurred at C-6 position. The degrees of substitution (DS) obtained from 13 C-NMR range from 0.23 to 1.27. The water solubility of the derivatives is in the order S-PCS3- >C-PCS3- >M-PCS3- >HE-PCS3- >HP-PCS3- This work provides a novel and nonpolluting process for the methylation, hydroxyethylation and hydroxypropylation of β -(1—>3)-D-glucan.

关键词： chemical structure Sulfation Carboxymethylation Methylation Hydroxyethylation Hydroxypropylation β-D- glucan Poria cocos sclerotium NMR

NMR Analysis to Identify Biuret Groups in Common Polyureas

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Chinese Journal of Polymer Science 2018年第10期36卷 1150-1156页

作者： Wei-Guang Qiu Fei-Long Zhang Xu-Bao Jiang Xiang-Zheng Kong College of Chemistry and chemical Engineering University of Jinan

Polyureas （PU） are well known as a class of high impact engineering materials, and widely used also in emerging advanced applications. As a general observation, most of them are only soluble in a very limited number of highly protonic solvents, which makes their chemical structure analysis a great challenge. Besides the presence of abundant hydrogen bonding, the poor solubility of PU in common organic solvents is often ascribed to the formation of biuret crosslinking in their molecular chains. To clarify the presence of biuret groups in PU has been of great interest. To this end, two samples, based on hexamethylene diisocyanate （HDI） and toluene diisocyanate （TDI） respectively, were synthesized by precipitation polymerization of each of these diisocyanates in water-acetone at 30℃. Their chemical structures were analyzed by high resolution magic angle spinning （HR-MAS） NMR, and through comparison of their NMR spectra with those of specially prepared biuret-containing polyurea oligomers, it was concluded that biuret group was absent in all the PU prepared at 30 ℃. In addition, this NMR analysis was also applied to a PU obtained by copolymerization of TDI with ethylene diamine （EDA） and water at 65 ℃ in EDA aqueous solution. It was confirmed that biuret unit was also absent in this PU and that EDA was more active than water towards TDI. The presence of EDA was crucial to the formation of uniform PU microspheres. This study provides therefore a reliable method for the analysis of PU chemical structure.

关键词： Diisocyanate Polyurea chemical structure Biuret NMR spectroscopy

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 *** 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 ***,doping-induced local composition and structure modification around the luminescent centers have yet to be *** 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 *** 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 *** 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