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Study on the pharmacological activities and chemical structures of Viburnum dilatatum
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作者 Zhiheng Gao Yufei Xi +2 位作者 Man Wang Xiaoxiao Huang Shaojiang Song 《Asian Journal of Traditional Medicines》 CAS 2023年第2期54-59,共6页
Viburnum dilatatum(jiami in Chinese),belonging to the Caprifollaceae family,is widely distributed in Japan and China.Phytochemical investigations of Viburnum dilatatum(V.dilatatum)have resulted in the isolation of tri... Viburnum dilatatum(jiami in Chinese),belonging to the Caprifollaceae family,is widely distributed in Japan and China.Phytochemical investigations of Viburnum dilatatum(V.dilatatum)have resulted in the isolation of triterpenoids,phenolic glycosides essential oil,norisoprenoids,etc.Research results have shown that the chemical constituents of V.dilatatum possess various pharmacological activities,including antihyperglycemic,antioxidant activity and antiulcer effects.This study reviewed the chemical constituents and pharmacological activities of V.dilatatum to provide practical and useful information for further research and development of this plant. 展开更多
关键词 Viburnum dilatatum pharmacological activity chemical structures
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THE CHEMICAL STRUCTURES OF SPIRAMINEN AND SPIRAMINOL 被引量:1
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作者 Xiao Jiang HAO Jun ZHOU +1 位作者 Kaoru FUJI Manabu NODE Laberatiry of Phytochemistry, Kunming Institute of Botany, Acedemia Sinica, Kunming, 650204 Institute of Chemical Research, Kyoto University, Kyoto 611, Japan 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第6期427-430,共4页
Two new Components, spiramine N (1) and spiraminol (2) were isolated from Spiraea japonica var. aecuminata Franch. Their structureswere elucidated bychemical and spectxal means.
关键词 CHC DATA THE chemical structures OF SPIRAMINEN AND SPIRAMINOL CDC KBR CHEN
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Research Progress on the Natural Anti-peptic Ulcer Chemical Structures 被引量:1
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作者 简舒心 田应园 +2 位作者 汪鋆植 胡为民 黄年玉 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2018年第11期1703-1710,共8页
Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, t... Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, terpenes, alkaloids, steroids, phenylpropanoids,glycosides and chromenes from natural herbs or traditional medicinal plants, and helps us analyze the structure-activity relationship(SAR) of natural products in healing of peptic ulcer for further drug development. 展开更多
关键词 peptic ulcer natural products medicinal plants chemical structures structure-activity relationship
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Chemical structures and thermochemical properties of bagasse lignin 被引量:1
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作者 Wu Shu-bin Guo Yi-li Wang Shao-guang Li Meng-shi 《Forestry Studies in China》 CAS 2006年第3期34-37,共4页
The chemical structures of bagasse EMAL (enzymatic hydrolysis/mild acidolysis lignin) were revealed quantitatively with ^31p-NMR, DFRC (derivatization followed by reductive cleavage). The thermochemical characteri... The chemical structures of bagasse EMAL (enzymatic hydrolysis/mild acidolysis lignin) were revealed quantitatively with ^31p-NMR, DFRC (derivatization followed by reductive cleavage). The thermochemical characteristics of bagasse and bagasse EMAL were evaluated with thermogravimetry. The results show that bagasse EMAL is mainly formed by the phenolic hydroxyl group of guaiacyl and syringyl units. The DBDO content in bagasse EMAL was found to be 0.180 mmol.g^-1. The decomposition characteristics of bagasse EMAL under elevated temperature were much different from that of bagasse. 展开更多
关键词 BAGASSE LIGNIN chemical structure ^31p-NMR DFRC THERMOGRAVIMETRY
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Facial amphiphilicity index correlating chemical structures with antimicrobial efficacy
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作者 Leman Buzoglu Kurnaz Yuanyuan Luo +8 位作者 Xiaoming Yang Amjed Alabresm Ryan Leighton Rani Kumar JiHyeon Hwang Alan W.Decho Prakash Nagarkatti Mitzi Nagarkatti Chuanbing Tang 《Bioactive Materials》 SCIE CSCD 2023年第2期519-527,共9页
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... 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. 展开更多
关键词 ANTIMICROBIAL Facial amphiphilicity chemical structure PEPTIDE
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Effect of demineralization on pyrolysis characteristics of LPS coal based on its chemical structure 被引量:1
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作者 Lin Qian Jinkai Xue +3 位作者 Chao Tao Chao Ma Xiaopeng Jiang Feiqiang Guo 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第2期181-195,共15页
The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupansh... The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupanshui raw coal(LPS-R)and Liupanshui demineralized coal(LPS-D)were analyzed by FTIR and solid-state 13C-NMR.The pyrolysis experiments were carried out by TG,and the pyrolysis kinetics was analyzed by three iso-conversional methods.FTIR and 13C-NMR results suggested that the carbon structure of LPS coal was not altered greatly,while demineralization promoted the maturity of coal and the condensation degree of the aromatic ring,making the chemical structure of coal more stable.The oxygen-containing functional groups with low bond energy were reduced,and the ratio of aromatic carbon with high bond energy was increased,decreasing the pyrolysis reactivity.DTG curve-fitting results revealed that the thermal weight loss of LPS coal mainly came from the cleavage of aliphatic covalent bonds.By pyrolysis kinetics analysis of LPS-R and LPS-D,the apparent activation energies were 76±4 to 463±5 kJ/mol and 84±2 to 758±12 kJ/mol,respectively,under different conversion rates.The reactivity of the demineralized coal was inhibited to some extent,as the apparent activation energy of pyrolysis for LPS-D increased by acid treatment. 展开更多
关键词 DEMINERALIZATION chemical structure of coal Coal pyrolysis Pyrolysis kinetics Iso-conversional
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EFFECT OF CHEMICAL STRUCTURE OF COMONOMERS ON THE PROPERTIES OF COPOLYESTERS 被引量:7
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作者 武荣瑞 高谨 李慧萍 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1997年第3期226-230,共5页
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. T... 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. 展开更多
关键词 COPOLYESTERS POLYETHYLENETEREPHTHALATE COMONOMER chemical structure
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Chemical interaction motivated structure design of layered metal carbonate hydroxide/MXene composites for fast and durable lithium ion storage 被引量:1
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作者 Huibin Guan Hanna He +1 位作者 Tianbiao Zeng Chuhong Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第12期633-641,I0015,共10页
Rational architecture design has turned out to be an effective strategy in improving the electrochemical performance of electrode materials for batteries.However,an elaborate structure that could simultaneously endow ... Rational architecture design has turned out to be an effective strategy in improving the electrochemical performance of electrode materials for batteries.However,an elaborate structure that could simultaneously endow active materials with promoted reaction reversibility,accelerated kinetic and restricted volume change still remains a huge challenge.Herein,a novel chemical interaction motivated structure design strategy has been proposed,and a chemically bonded Co(CO_(3))_(0.5)OH·0.11 H_(2)O@MXene(CoCH@MXene)layered-composite was fabricated for the first time.In such a composite,the chemical interaction between Co^(2+)and MXene drives the growth of smaller-sized CoCH crystals and the subsequent formation of interwoven CoCH wires sandwiched in-between MXene nanosheets.This unique layered structure not only encourages charge transfer for faster reaction dynamics,but buffers the volume change of CoCH during lithiation-delithiation process,owing to the confined crystal growth between conductive MXene layers with the help of chemical bonding.Besides,the sandwiched interwoven CoCH wires also prevent the stacking of MXene layers,further conducive to the electrochemical performance of the composite.As a result,the as-prepared CoCH@MXene anode demonstrates a high reversible capacity(903.1 mAh g^(-1)at 100 mA g^(-1))and excellent cycling stability(maintains 733.6 mAh g^(-1)at1000 mA g^(-1)after 500 cycles)for lithium ion batteries.This work highlights a novel concept of layerby-layer chemical interaction motivated architecture design for futuristic high performance electrode materials in energy storage systems. 展开更多
关键词 chemical interaction motivated structure design Layer-by-layer structure Metal carbonate hydroxide Few-layer MXene Fast and durable lithium ion storage
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NON-EQUILIBRIUM STATIONARY STATE IN CHEMICAL REACTION OF SiO_2/Fe AT INTERFACE OF SLAG/METAL AND ITS STABILITY DURING ARC WELDING 被引量:2
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作者 LI Xiaoquan DU Zeyu YANG Xuguang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第1期44-46,共3页
For characteristics of open and far from thermodynamic equilibrium in welding chemical reaction, a new kind of quantitative method, which is used to analyze direction and extent for chemical reaction of SiO2/Fe during... For characteristics of open and far from thermodynamic equilibrium in welding chemical reaction, a new kind of quantitative method, which is used to analyze direction and extent for chemical reaction of SiO2/Fe during quasi-steady state period, is introduced with the concept of non-equilibrium stationary state. The main idea is based on thermodynamic driving forces, which result in non-zero thermodynamic fluxes and lead to chemical reaction far away from thermodynamic equilibrium. There exists certain dynamic equilibrium relationship between rates of diffusion fluxes in liquid phase of reactants or products and the rate equation of chemical reaction when welding is in quasi-steady state. As result of this, a group of non-linear equations containing concentrations of all substances at interface of slag/liquid-metal may be established. Moreover the stability of this non-equilibrium stationary state is discussed using dissipative structure theory and it is concluded theoretically that this non-equilibrium stationary state for welding chemical reaction is of stability. 展开更多
关键词 Welding chemical metallurgy Non-equilibrium stationary state Dissipative structure Stability
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ISOLATION, PROPERTIES AND CHEMICAL STRUCTURE OF A GLUCAN FROM GLYCYRRHIZIA URALENSIS FISCH
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作者 Ji Nian FANG and Bin Can LIN Shanghai Institute of Materia Medica, Academia Sinica, Shanghai 200031 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第8期627-628,共2页
A new polysaccharide,GBW was obtained homogeneous as determined by HPLC from the roots of Glycyrrhizia uralensis Fisch. The molecular weight was estimated to be 4000. The component sugar was identified as glucose only... A new polysaccharide,GBW was obtained homogeneous as determined by HPLC from the roots of Glycyrrhizia uralensis Fisch. The molecular weight was estimated to be 4000. The component sugar was identified as glucose only. The specific rotation [α]^(28)_D (C=0.1,H_2O) was +1200. The α-configuration was established by IR and ^(13)C NMR. Methylation analysis, periodate oxidation, Smith degradation, partial hydrolysis, KI-I_2 reaction and ^(13)C NMR showed that GBW is a new (1→4)linked linear α-D-glucan. The structure is shown as 1. 展开更多
关键词 HPLC PROPERTIES AND chemical STRUCTURE OF A GLUCAN FROM GLYCYRRHIZIA URALENSIS FISCH ISOLATION
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THE CHEMICAL STRUCTURE OF HYPODEMAPYRAZIN
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作者 Ying Hua LU Ya Min CHEN +4 位作者 Xin Min WUN Hong En WANG Cun Shen MA Rong Long ZHU De Quan YU Jining Medical College, Jining. Shandong 272113 Institute of Materia Medica, Chinese Academy of Medical Sciences, Bejing 100050 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第7期609-610,共2页
A novel alkaloid named Hypodemapyrazine was isolated from the whole plantof a fern, Hypodematium sinense Iwatsuki. Its chemical structure has been elucidated to be a novel skeleton containing a hydro-pyrazine by means... A novel alkaloid named Hypodemapyrazine was isolated from the whole plantof a fern, Hypodematium sinense Iwatsuki. Its chemical structure has been elucidated to be a novel skeleton containing a hydro-pyrazine by means of UV, IR, ~1H-NMR, ^(13)C-NMR and HRMS spectroscopy. 展开更多
关键词 THE chemical STRUCTURE OF HYPODEMAPYRAZIN UV
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LOCALIZED STUDIES ON ELECTRONIC STRUCTURE AND CHEMICAL BOND FOR [NCCuS_2MoS_2]^(2-) CLUSTER
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作者 Qian Shu LI Song LI Ao Qing TANG Institute of Theoretical Chemistry, Jilin University, Changchun, 130023. 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第7期561-562,共2页
The canonical and locatized molecutar orbiters of [NCCuS_2NoS_2]^(2-) cluster were calculated by means of CNDO quantum chemistry method. Then the energy and properties of corresponding chemicat bonds were discussed, e... The canonical and locatized molecutar orbiters of [NCCuS_2NoS_2]^(2-) cluster were calculated by means of CNDO quantum chemistry method. Then the energy and properties of corresponding chemicat bonds were discussed, especially, Cu-Sb-No three center conjugated π bonds and No-St-No conjugated π bonds were accounted for. 展开更多
关键词 LOCALIZED STUDIES ON ELECTRONIC STRUCTURE AND chemical BOND FOR NCCuS2MoS2 CLUSTER
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QUANTUM CHEMICAL CALCULATIONS ON THE ELECTRONIC STRUCTURE AND SPECTRA OF[Mo_3O_4-nSn]^(4+)(n=O-4)CLUSTER CATIONS
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作者 Zhi Ru LI Qian Shu LI Ji Kang FANG Zhi Ren ZHENG Jun ZHENG Department of Chemistry,Jilin University,Changchun,130023 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第1期43-46,共4页
The electronic structure and spectra of [Mo3O4-nSn]^(4+)(n=0-4) cations were calculated by means of INDO/CI quantum chemistry method to account for the experimental data of their spectra in water solutions.
关键词 HOMO n=O-4)CLUSTER CATIONS Ho LUMO N QUANTUM chemical CALCULATIONS ON THE ELECTRONIC STRUCTURE AND SPECTRA OF[Mo3O4-nSn MO
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A MICROCOMPUTER ANALYTIC SYSTEM FOR CRYSTAL STRUCTURE USED IN CHEMICAL LABORATORIES
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作者 Yang L(U|¨) Institute of Materia Medica,Chinese Academy of Medical Sciences,Beijing,100050Bo Mu WU Institute of Biophysics,Academia Sinica,Beijing,100101 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第8期637-640,共4页
The program system described in this paper is a microcomputer analytic system for X-ray crystal structure used in chemical laboratories.The abbreviated name is NOMCSDP.NOMCSDP has been developed on the basis of NRCVAX... The program system described in this paper is a microcomputer analytic system for X-ray crystal structure used in chemical laboratories.The abbreviated name is NOMCSDP.NOMCSDP has been developed on the basis of NRCVAX and SHELXS-86.It is a software for X- ray crystal structure analysis of organic molecules,especially natural organic molecules(1-7). 展开更多
关键词 A MICROCOMPUTER ANALYTIC SYSTEM FOR CRYSTAL STRUCTURE USED IN chemical LABORATORIES
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Spectroscopic Elucidation of the Links between Char Morphology and Chemical Structure of Coals of Different Ranks
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作者 Andrew O. Odeh 《Advances in Chemical Engineering and Science》 2016年第4期379-398,共20页
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 t... 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 m<sup>2</sup>/cm<sup>3</sup> 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 m<sup>2</sup>/cm<sup>3</sup> particle volume for sub-bituminous;440.60 - 241.70 m<sup>2</sup>/cm<sup>3</sup> particle volume for light volatile bituminous;452.71 - 247.73 m<sup>2</sup>/cm<sup>3</sup> particle volume for high volatile bituminous;349.11 - 347.52 m<sup>2</sup>/cm<sup>3 </sup>particle volume for semi-anthracite and 333.60 - 125.34 m<sup>2</sup>/cm<sup>3</sup> 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. 展开更多
关键词 Coal Char Char Morphology chemical Structure XRD SAXS
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The alkynyl-containing compounds from mushrooms and their biological activities
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作者 Ji-shuang Qi Yingce Duan +3 位作者 Zhao-chen Li Jin-ming Gao Jianzhao Qi Chengwei Liu 《Natural Products and Bioprospecting》 CSCD 2023年第1期138-158,共21页
Mushrooms have been utilized by humans for thousands of years due to their medicinal and nutritional properties.They are a crucial natural source of bioactive secondary metabolites,and recent advancements have led to ... Mushrooms have been utilized by humans for thousands of years due to their medicinal and nutritional properties.They are a crucial natural source of bioactive secondary metabolites,and recent advancements have led to the isolation of several alkynyl-containing compounds with potential medicinal uses.Despite their relatively low abundance,naturally occurring alkynyl compounds have attracted considerable attention due to their high reactivity.Bioactivity studies have shown that alkynyl compounds exhibit significant biological and pharmacological activities,including antitumor,antibacterial,antifungal,insecticidal,phototoxic,HIV-inhibitory,and immunosuppressive properties.This review systematically compiles 213 alkynyl-containing bioactive compounds isolated from mushrooms since 1947 and summarizes their diverse biological activities,focusing mainly on cytotoxicity and anticancer effects.This review serves as a detailed and comprehensive reference for the chemical structures and bioactivity of alkynyl-containing secondary metabolites from mushrooms.Moreover,it provides theoretical support for the development of chemical constituents containing alkynyl compounds in mushrooms based on academic research and theory. 展开更多
关键词 MUSHROOM Alkynyl compounds Bioactivity chemical structures
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Time-shift effect of spontaneous combustion characteristics and microstructure difference of dry-soaked coal
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作者 Yikang Liu Haiyan Wang +4 位作者 Huiyong Niu Tao Wang Zhiwen Chen Yuqi Chen Qingjie Qi 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第4期171-185,共15页
The physical and chemical properties of the air-dried residual coal after soaking in the goaf will change,resulting in an increase in its spontaneous combustion tendency.This study aimed to look into the features and ... The physical and chemical properties of the air-dried residual coal after soaking in the goaf will change,resulting in an increase in its spontaneous combustion tendency.This study aimed to look into the features and mechanism of soaked-dried coal's spontaneous combustion.Five samples of coal were dried to various degrees,and the weight loss features during thermal processing were examined.Based on this,the pore structure and chemical structure characteristics of the coal samples with the highest tendency to spontaneous combustion were quantitatively examined,and the mechanism by which soaking-drying afected the spontaneous combustion heating process of the remaining coal in goaf was investigated in turn.The results show that T1 decreases with the increase of drying time,T2–T6 shows a fuctuating change,and the ignition activation energy of 36-S-Coal is smaller than that of other coal samples.The pore type of 36-S-Coal changes from a oneend closed impermeable pore to an open pore,and the pore group area is large.During the 36 h drying process,the internal channels of the coal were dredged,and a large number of gravels and minerals were precipitated from the pores with the air fow.A large number of gravels were around the pores to form a surface structure that was easy to adsorb various gases.Furthermore,infrared spectroscopy was used to analyze the two coal samples.It was found that soaking and drying did not change the functional group types of coal samples,but the fatty chain degree of 36-S-Coal was reduced to 1.56.It shows that the aliphatic chain structure of coal is changed after 36 h of drying after 30 days of soaking,which leads to the continuous shedding of aliphatic chain branches of residual coal,and the skeleton of coal is looser,which makes the low-temperature oxidation reaction of 36-S-Coal easier.Based on the above results,the coal-oxygen composite mechanism of water-immerseddried coal is obtained,and it is considered that the key to the spontaneous combustion oxidation process of coal is to provide oxygen atoms and accelerate the formation of peroxides. 展开更多
关键词 Water-soaked coal Coal spontaneous combustion FTIR TG-DTG Pore structure chemical structure parameters
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Preparation and Properties of Chinese Lacquer Modified by Methylolureas
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作者 Qiang Xiao Yanjun Cao +6 位作者 Hailu Tan Qiaoling Feng Xinyue Gu Jianhua Lyu Hui Xiao Ming Chen Yuzhu Chen 《Journal of Renewable Materials》 SCIE EI 2023年第2期1003-1016,共14页
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 teste... 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. 展开更多
关键词 Raw lacquer methylolureas PROPERTIES thermal behavior chemical structure
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An Auto-Grading Oriented Approach for Off-Line Handwritten Organic Cyclic Compound Structure Formulas Recognition
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作者 Ting Zhang Yifei Wang +3 位作者 Xinxin Jin Zhiwen Gu Xiaoliang Zhang Bin He 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第6期2267-2285,共19页
Auto-grading,as an instruction tool,could reduce teachers’workload,provide students with instant feedback and support highly personalized learning.Therefore,this topic attracts considerable attentions from researcher... Auto-grading,as an instruction tool,could reduce teachers’workload,provide students with instant feedback and support highly personalized learning.Therefore,this topic attracts considerable attentions from researchers recently.To realize the automatic grading of handwritten chemistry assignments,the problem of chemical notations recognition should be solved first.The recent handwritten chemical notations recognition solutions belonging to the end-to-end trainable category suffered fromthe problem of lacking the accurate alignment information between the input and output.They serve the aim of reading notations into electrical devices to better prepare relevant edocuments instead of auto-grading handwritten assignments.To tackle this limitation to enable the auto-grading of handwritten chemistry assignments at a fine-grained level.In this work,we propose a component-detectionbased approach for recognizing off-line handwritten Organic Cyclic Compound Structure Formulas(OCCSFs).Specifically,we define different components of OCCSFs as objects(including graphical objects and text objects),and adopt the deep learning detector to detect them.Then,regarding the detected text objects,we introduce an improved attention-based encoder-decoder model for text recognition.Finally,with these detection results and the geometric relationships of detected objects,this article designs a holistic algorithm for interpreting the spatial structure of handwritten OCCSFs.The proposedmethod is evaluated on a self-collected data set consisting of 3000 samples and achieves promising results. 展开更多
关键词 Handwritten chemical structure formulas structure interpretation components detection text recognition
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Structural and Chemical Characterization of the Ediacaran Embryo-Like Fossils via the Combination of 3D-XRM and FIB-SEM Approaches
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作者 Qian Chen Weichen Sun +1 位作者 Suping Wu Zongjun Yin 《Journal of Earth Science》 SCIE CAS CSCD 2024年第4期1204-1214,共11页
The three-dimensional(3D)morphology,anatomy,and in-situ chemical composition analysis of fossils are crucial for systematic paleontology and determining their phylogenetic positions.Scanning electron microscopy(SEM)co... The three-dimensional(3D)morphology,anatomy,and in-situ chemical composition analysis of fossils are crucial for systematic paleontology and determining their phylogenetic positions.Scanning electron microscopy(SEM)coupled with energy-dispersive X-ray spectroscopy(EDS),offers valuable structural and chemical information for the analysis of fossils.However,its primary limitation is the restriction to two-dimensional surface data,which limits the exploration of fossils’3D complexities.Conversely,3D X-ray microscopy(3D-XRM),also known as a novel form of micro-computed tomography(micro-CT)facilitates the non-destructive 3D reconstruction of fossil specimens.Nevertheless,it lacks the capability to provide in-situ compositional data.Acknowledging the constraints inherent in these individual techniques,and in response to the evolving requirements of paleontological research,this study introduces an integrated approach that combines 3D-XRM with EDS-coupled focused ion beam scanning electron microscopy(FIB-SEM).This innovative strategy is designed to synergize the advantages of both techniques,thereby addressing challenges that conventional methods cannot.It enables the rapid identification of regions of interest(ROI)within fossil specimens at micrometer resolution.Subsequently,this method collects detailed data on both 3D structures and chemical compositions at the nanometer scale for the identified ROI.This integrated approach represents a significant advancement in paleontological and geological research methodologies,promising to meet the increasing demands of these fields. 展开更多
关键词 Embryo-like microfossils structural and chemical characterization 3D-XRM FIB-SEM 3D reconstruction
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