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A New Triterpenoid Glycoside from Decaisnea Fargesii

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Chinese Chemical Letters 1999年第5期10卷 397-400页

作者： kong, j Lu, RH Gao, HX Wang, M Wang, YP Wang, HQ Chinese Acad Sci Lanzhou Inst Chem Phys Lanzhou 730010 Peoples R China NW Normal Univ Dept Chem Lanzhou 730070 Gansu Peoples R China

A new triterpenoid glycoside, named decaisoside F. has been isolated from Decaisnea faresii. Its structure was determined on basis of chi mical method, FAB-MS. homonuclear and heteronuclear correlation esperiments. including H-1--(HCOSY)-H-1. H-1--C-13 COSY, TOSCY, HMBC and NOESY techniques to be 3-O-beta-D- xylopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-Larabinopyranosyl) hederagenin 28-O-beta-D-xylopyranosyl (1-->4)-beta-D-glucopyrancrsyl (1-->6)-beta-D-glucopyranoside.

关键词： Decaisnea fargesii triterpenoid glycoside decaisoside F 2D-NMR

Conformation and Counterion Distribution of Polyelectrolyte in Solution as Viewed from Dielectric Approach

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Chinese journal of Polymer Science 2024年第9期42卷 1278-1301,I0005页

作者： kong-Shuang Zhao College of Chemistry Beijing Normal UniversityBeijing 100875China

Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding ***,the subject of polyelectrolyte solutions has attracted a wide range of interests in both basic and applied research,and has also been extensively ***,the understanding of the molecular dynamics and conformation of polyelectrolytes in solution remains to be deepened,and universal consensus on some key issues have not been *** methods have contributed to solving the above problems in different ways,including dielectric relaxation spectroscopy(DRS).In this perspective,we briefly reviewed the history of dielectric spectroscopic research on polyelectrolyte solution,with emphasis on summarizing our *** particular,we expound the characteristics of DRS and its ability to obtain the internal information of the system of ***,we evaluate the advantages and limitations of the dielectric method and discussed future prospects of this field.

关键词： Polyelectrolyte Dielectric relaxation spectroscopy Chain conformation Thermosensitive microgel PNIPAM microgel Spherical polyelectrolyte brushes

Flat jet electrochemical milling of TC4 alloy with tailoring backward parallel flow

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Chinese journal of Aeronautics 2024年第4期37卷 574-592页

作者： Huanghai kong Ningsong QU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In flat jet electrochemical milling, the electrolyte forms a backward parallel flow after impacting the workpiece, resulting in a weak current density distribution on the workpiece. Poor surface quality usually occurs on the machined titanium alloy surface because it inevitably suffers from the weak current density. In this study, a method of flat jet electrochemical milling with tailoring the backward parallel flow was proposed to eliminate the negative effects caused by the weak current density. Multiphysics simulations are carried out to comprehend the mechanism of flat jetEC milling with tailoring backward parallel flow and better construct the novel tool *** on flat jet electrochemical milling of TC4 alloy with and without tailoring backward parallel flow are conducted. The results reveal that, compared with flat jet electrochemical milling without tailoring backward parallel flow, the recommended tool reduces the surface roughness by86% to 93%, and improves the material removal rate by 93% to 163% with different feed ***, the recommended tool is more conducive to maintaining the inherent hardness of the material. Finally, a surface with low Sa of 0.37 μm is obtained.

关键词： Flat jet electrochemical milling TC4 alloy Surface roughness Micro-hardness Material removal rate

Soil inorganic amendments produce safe rice by reducing the transfer of Cd and increasing key amino acids in brown rice

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journal of Environmental Sciences 2024年第2期136卷 121-132页

作者： Fanyi kong Shenggao Lu Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment Key Laboratory of Environmental Remediation and Ecosystem HealthMinistry of EducationCollege of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China

The digestibility of cadmium(Cd)in brown rice is directly related to amino acid metabolism in rice and human *** our field study,three kinds of alkaline calcium-rich soil inorganic amendments(SIAs)at three dosages were applied to produce safe rice and improve the quality of rice in Cd-contaminated *** the increased application of SIA,Cd content in iron plaque on rice root significantly increased,the transfer of Cd from rice root to grain significantly decreased,and then Cd content in brown rice decreased *** vitro digestibility of Cd in brown rice was estimated by a physiologically based extraction *** showed that more than 70%of Cd in brown rice could be digested by simulated gastrointestinal *** on the total and digestible Cd contents in brown rice to evaluate the health risk,the application of 2.25 ton SIA/ha could produce safe rice in acidic slightly Cd-contaminated paddy *** amino acids(AAs)in brown rice were determined by high-performance liquid *** contents of 5 key AAs(KAAs)that actively respond to environmental changes increased significantly with the increased application of *** structural equation model indicated that KAAs could be affected by the Cd translocation capacity from rice root to grain,and consequently altered the ratio of indigestible Cd in brown *** formation of indigestible KAAs-Cd complexes by combining KAAs(phenylalanine,leucine,histidine,glutamine,and asparagine)with Cd in brown rice could be considered a potential mechanism for reducing the digestibility of Cd.

关键词： Cadmium digestibility Soil inorganic amendments Safe rice Amino acid Priming effect Health risk

Achieving ultrahigh strength and ductility in high-entropy alloys via dual precipitation

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journal of Materials Science & Technology 2023年第35期166卷 67-77页

作者： j.M.Guo B.C.Zhou S.Qiu H.j.kong M.C.Niu j.H.Luan T.L.Zhang H.Wu Z.B.jiao Department of Mechanical Engineering Research Institute for Advanced ManufacturingThe Hong Kong Polytechnic UniversityHong KongChina The Hong kong Polytechnic University Shenzhen Research Institute Shenzhen 518057China Department of Materials Science and Engineering City University of Hong KongHong KongChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

The strength-ductility trade-offhas been a longstanding dilemma in metallic *** we report an innovative approach to achieve a high strength-ductility synergy via dual precipitation of sheared and bypassed precipitates.(Ni_(2) Co_(2) FeCr)_(96-x) Al_(4) Nb_(x)(at.%)alloys strengthened by nanoscale L12 particles and Laves precipitates were selected as a model for this study,and their precipitate microstructures and mechanical properties were thoroughly *** dual-precipitation-strengthened alloys exhibit a yield strength of more than 1400 MPa,an ultimate tensile strength of over 1800 MPa,and a uniform elon-gation of 18%,thus achieving a high strength-ductility *** analysis reveals that the nanoscale L1_(2) precipitates contribute to the strength via the particle shearing mechanism,whereas the Laves phase provides the strengthening through the Orowan bypass *** study of deformation microstruc-tures shows that the L1_(2) precipitates are sheared by stacking faults,which facilitates long-range disloca-tion gliding through the *** a result,deformation induces the formation of hierarchical stacking fault networks and immobile Lomer-Cottrell locks,which effectively enhance the work hardening ca-pability and plastic stability,thereby resulting in a high ductility at high strength *** are piled-up against the interface between the Laves precipitates and matrix,which increases the work hardening capability at the early stages of plastic deformation but causes stress *** dual precipitation strategy may be useful for many other alloys for achieving superior mechanical properties for technological applications.

关键词： High-entropy alloy Dual precipitation Precipitation strengthening Deformation mechanism

Competition of Composition Fluctuation Modes in Weakly Segregated Salt-doped Symmetric Diblock Copolymers

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Chinese journal of Polymer Science 2024年第9期42卷 1375-1385,I0008页

作者： Yuan-Xin Zhou Xian kong South China Advanced Institute for Soft Matter Science and Technology School of Emergent Soft MatterSouth China University of TechnologyGuangzhou510640China Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices South China University of TechnologyGuangzhou510640China

Salt-doped block copolymers have widespread applications in batteries,fuel cells,semiconductors,and various industries,where their properties crucially depend on phase separation ***,investigations into salt-doped diblock copolymers have predominantly focused on microphase separation,overlooking the segregation between ionic and polymeric *** study employs weak segregation theory to explore the interplay between phase separation dominated by the polymer-modulated mode and the salt-out-modulated mode,corresponding to microscopic and macroscopic phase separations,*** comparing diblock copolymers doped with salts to those doped with neutral solvents,we elucidate the significant role of charged species in modulating phase *** phase separation mode exhibits a transition between the polymer-modulated and salt-out-modulated modes at different *** systems doped with neutral solvents,this transition is stepwise,while in salt-ion-doped systems,it is *** a sufficiently large Flory-Huggins parameter between ions and polymers,the salt-out-modulated mode becomes dominant,promoting macrophase *** to the solvation effect of salt ions,salt-doped systems are more inclined to undergo microphase ***,we explore factors influencing the critical wavenumber of phase separation,including doping level and the Flory-Huggins parameters between two blocks and between ions and polymeric *** findings reveal that in a neutral solvent environment,these factors alter only the boundary between micro-and macro-phase separations,leaving the critical wavenumber unchanged in microphase separation ***,in a salt-doped environment,the critical wavenumber of microphase separation varies with these *** provides valuable insights into the pivotal role of electrostatics in the phase separation of salt-doped block copolymers.

关键词： Block copolymer Phase separation Field theory Salt-doped

Non-dimensional analysis on blast wave propagation in foam concrete:Minimum thickness to avoid stress enhancement

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Defence Technology（防务技术） 2024年第6期36卷 30-46页

作者： Ya Yang Xiangzhen kong Qin Fang State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007JiangsuChina

Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau ***,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast *** investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov *** difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress *** difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are *** particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is ***,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering.

关键词： Foam concrete Blast wave propagation Non-dimensional analysis Stress enhancement

Enhanced Natural Convection for Accelerating Melting of Phase Change Material in Cellular Structure through Inserting Fin

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journal of Thermal Science 2024年第2期33卷 548-563页

作者： kong Dekui ZHANG Yongcun LIU Shutian State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian116024China

The design of thermal conductivity enhancers(TCE) is quite critical to overcoming the disadvantage of the poor thermal conductivity of phase change materials(PCM).The main contribution of this study is firstly to discuss how to actively enhance natural convection of the melted PCM in cellular structure by the fin formed in the structure under the condition of the same metal mass,apart from simultaneously improving heat conduction,which can boost the heat transfer ***,a tailored hybrid fin-lattice structure(HFS) as TCE is designed and fabricated by additive manufacturing(AM).A two-equation numerical method is applied to study the heat transfer of the PCM,and its feasibility is validated with the experimental *** numerical results indicate that enhanced natural convection and improved heat conduction can be obtained simultaneously when a well-designed fin is embedded into a lattice *** enhanced natural convection results in the improved melting rate and the decreased wall temperature;e.g.,the complete melting time and the wall temperature are reduced by 11.6% and 19.7%,respectively,because of the fin for metal ***,the parameters of HFS including the porosity,pore density,and fin dimension have a great impact on the heat *** enhancement effect of the fin for HFS on the melting rate of the PCM increases as the thermal conductivity of the base material *** example,when the fin is introduced into the lattice structure,the complete melting time is reduced by 24.1% for metal *** summary,this study enables us to obtain a good understanding of the mechanism of the heat transfer and provides necessary experimental data for the structural design of HFS fabricated by AM.

关键词： natural convection heat transfer enhancement phase change material additive manufacturing hybrid fin-lattice structure

Al-modified yolk-shell silica particle-supported NiMo catalysts for ultradeep hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene:Efficient accessibility of active sites and suitable acidity

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Petroleum Science 2024年第1期21卷 654-666页

作者： Ke Yu Wei-Min kong Zhen Zhao Ai-jun Duan Lian kong Xi-Long Wang State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang 110034LiaoningChina

Yolk-shell SiO2 particles(YP)with center-radial meso-channels were fabricated through a simple and effective ***-containing YP-supported NiMo catalysts with different Al amounts(NiMo/AYP-x,x=Si/Al molar proportion)were prepared and dibenzothiophene(DBT)and 4,6-dimethyl-dibenzothiophene(4,6-DMDBT)were employed as the probes to evaluate the hydrodesulfurization(HDS)catalytic *** as-prepared AYP-x carriers and corresponding catalysts were characterized by some advanced characterizations to obtain deeper correlations between physicochemical properties and the HDS *** average pore sizes of series AYP-x supports are above 6.0 nm,which favors the mass transfer of organic *** cavity between the yolk and the shell is beneficial for the enrichment of S-containing compounds and the accessibility between reactants and active *** embedded into the silica framework could facilitate the formation of Lewis(L)and Brønsted(B)acid sites and adjust the metal-support interaction(MSI).Among all the as-synthesized catalysts,NiMo/AYP-20 catalyst shows the highest HDS *** improved HDS activity of NiMo/AYP-20 catalyst is attributed to the perfect combination of excellent structural properties of the yolk-shell mesoporous silica,enhanced acidity,moderate MSI,and good accessibility/dispersion of active components.

关键词： Al-containing yolk-shell silica particles Accessibility Acidity Metal-support interaction Hydrodesulfurization