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Damage evolution and removal behaviors of GaN crystals involved in double-grits grinding

International Journal of Extreme Manufacturing 2024年第2期6卷 469-484页

作者： chen Li Yuxiu Hu Zongze wei Chongjun Wu Yunfeng Peng Feihu Zhang Yanquan Geng State Key Laboratory of Robotics and System(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China Key Laboratory of Microsystems and Microstructures Manufacturing(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China College of Mechanical Engineering Donghua UniversityShanghai 201620People’s Republic of China Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005People’s Republic of China

Elucidating the complex interactions between the work material and abrasives during grinding of gallium nitride(GaN)single crystals is an active and challenging research *** this study,molecular dynamics simulations were performed on double-grits interacted grinding of GaN crystals;and the grinding force,coefficient of friction,stress distribution,plastic damage behaviors,and abrasive damage were systematically *** results demonstrated that the interacted distance in both radial and transverse directions achieved better grinding quality than that in only one *** grinding force,grinding induced stress,subsurface damage depth,and abrasive wear increase as the transverse interacted distance ***,there was no clear correlation between the interaction distance and the number of atoms in the phase transition and dislocation *** interacted distances between abrasives can decrease grinding force,coefficient of friction,grinding induced stress,subsurface damage depth,and abrasive wear during the grinding *** results of grinding tests combined with cross-sectional transmission electron micrographs validated the simulated damage results,*** atoms,high-pressure phase transition,dislocations,stacking faults,and lattice *** results of this study will deepen our understanding of damage accumulation and material removal resulting from coupling between abrasives during grinding and can be used to develop a feasible approach to the wheel design of ordered abrasives.

关键词： grinding double-grits molecular dynamics damage material removal gallium nitride

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High amylose to amylopectin ratios in nitrogen-free diets decrease the ileal endogenous amino acid losses of broiler chickens

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Animal Nutrition 2023年第3期14卷 111-120页

作者： Huajin Zhou Tahir Mahmood wei Wu Yanhong chen Yao Yu Jianmin Yuan State Key Laboratory of Animal Nutrition College of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China Adisseo Animal Nutrition DMCCDubai 00000United Arab Emirates

This study explored the variation of ileal endogenous amino acid(IEAA)losses and its influencing factors in chickens offered nitrogen-free diets(NFD)containing different ratios of amylose to amylopectin(AM/AP).A total of 252 broiler chickens at 28 d old were randomly allocated into 7 treatment groups for a 3-d *** dietary treatments included a basal diet(control),a NFD containing corn starch(CS),and 5NFD with AM/AP ratios of 0.20,0.40,0.60,0.80,and 1.00,*** the AM/AP ratio increased,the IEAA losses of all AAs,starch digestibility and maltase activity linearly decreased(P<0.05),but the DM digestibility linearly and quadratically decreased(P<0.05).Compared with the control,the NFD increased the number of goblet cells and its regulatory genes mucin-2 and krüppel-like factor 4(KLF-4)while decreasing serum glucagon and thyroxine concentrations,ileal villus height,and crypt depth(P<0.05).Additionally,NFD with lower AM/AP ratios(0.20 and 0.40)decreased the ileal microbiota species richness(P<0.05).In all NFD groups,the number of Proteobacteria increased whereas the abundance of Firmicutes dropped(P<0.05).However,the broilers in the AM/AP 0.60 group were closer to the digestive physiological state of chickens fed the control diet,with no significant change in maltase activity and mucin-2 expression(P<0.05).In conclusion,increasing AM/AP ratio in a NFD decreased the IEAA losses and the apparent ileal digestibility of starch but inevitably resulted in malnutrition and disruption of gut microbiota *** study recommends AM/AP in NFD at 0.60 to measure IEAA of broiler chickens.

关键词： Broiler chicken Endogenous amino acid losses Nitrogen-free diet Amylose Amylopectin Goblet cells

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Advances in gas sensors of tetrapyrrolato-rare earth sandwich-type complexes——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

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Journal of Rare Earths 2021年第2期39卷 113-120页

作者： Xiangjie Tang Qi Liu Chuangyu wei Xuehui Lv zhicheng Jin Yanli chen Jianzhuang Jiang School of Materials Science and Engineering College of ScienceChina University of Petroleum(East China)Qingdao 266580China Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials Department of ChemistryUniversity of Science and Technology BeijingBeijing 100083China

In recent years,sandwich-type rare earth tetrapyrrole derivatives,have attracted more and more attention as material for conductimetric *** have not only great chemical stability and processability,but also flexible molecular structure,which is a key to adjustable semiconductor *** this mini review,we focus mainly on the development of tetrapyrrolato-rare earth sandwich-type complexes as the semiconducting active layer in the gas sensors published in the last ten years(2010-2020).The main part includes two *** the single component gas sensing of sandwich rare earth tetrapyrrole complexes,we describe the influence factors of the single-component semiconducting active layer on the sensing performance of tetrapyrrolato-rare earth sandwich-type complexes,including substituents,central metals and π-conjugate *** the multi-component gas sensors,the synergistic effect between tetrapyrrolato-rare earth sandwich-type complex and other materials on improving sensitivity and conductivity has been discussed briefly.

关键词： Sandwich-type rare earth tetrapyrrole complex Phthalocyanine Gas sensor Rare earths

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Application of nanoscale metal-organic frameworks in tumor immunotherapy

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Rare Metals 2024年第10期43卷 4867-4883页

作者： Xiao-Xuan Zeng Jing-Sheng Lu Dong-wei Ma Yu-Ting Huang Ling chen Gang Wang Qing chen Ning Lin College of Pharmacy Guangxi Scientific Research Center of Traditional Chinese MedicineGuangxi University of Chinese MedicineNanning 530200China Guangxi Zhuang Yao Medicine Center of Engineering and Technology Nanning 530200China

Immunotherapy has attracted wide attention because it can not only kill tumor cells but also effectively prevent tumor ***,due to the poor efficacy of the monotherapy in tumor immunotherapy,combination therapies are needed to enhance their efficacy,such as chemodynamic therapy/immunotherapy,photodynamic therapy/immunotherapy,sonodynamic therapy/immunotherapy and so *** metal-organic frameworks(nMOFs)are widely used for drug delivery because of their rich and variable composition,high drug loading capacity and good *** with other conventional drug delivery systems(DDSs),nMOFs play more advantageous role in inducing immune cell death of tumor cells and combination *** article focuses on the application of n MOFs in tumor immunotherapy in terms of their use as gatekeepers,supplementary agents and drug carriers,respectively,with the aim of providing some ideas and references for the design of smart nanoscale DDS for tumor immunotherapy.

关键词： Metal–organic frameworks Tumor Immunotherapy Drug delivery system

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Effect of boron on microstructure and mechanical properties of cast Ti-44Al6-Nb ingots

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China Foundry 2015年第1期12卷 9-14页

作者： Jian-chong Li Rui-run chen zhi-kun Ma Xiao-yu chen Hong-sheng Ding Jing-jie Guo AVIC Beijing Institute of Aeronautical Materials School of Materials Science and Engineering Harbin Institute of Technology Department of Tank Repair People's Liberation Army Armored Force Engineering Institute

In order to improve the mechanical properties of Ti Al alloys, especially the ductility at room temperature, and to study the effect of boron(B) on Ti Al alloys, different contents(0, 0.1, 0.3, 0.6, 0.9, 1.2, at.%) of B were added into Ti-44Al-6Nb alloys to prepare ingots. The surface quality, macrostructure, microstructure, compressive properties and fracture surface of the ingots were studied. The results show that B has little influence on the surface quality except that there are some dark spots on the surface when the content of B is 0.9%. B can refine the grains. The average grain size decrease from about 0.8 mm to 0.088 mm with increasing B content. Meanwhile, the grain morphology of these ingots changes from big equiaxed grains with lamellars to fine equiaxed grains. When the content of B is 1.2%, the primary Ti B2 phase forms in the liquid phase and increases the nucleation rate, leading to further refinement of the grains. The compressive testing results show that B can increase the strength and the ductility, the compressive strength and compressibility can reach 2,037.8 MPa and 26.7% from 1,156.2 MPa and 10.2% when the boron content is 0.6%, which is resulted from grain refining and grain boundary strengthening. It is found that the compressive strength and the compressibility are relatively stable when the B content is more than 0.3%.

关键词： boron TiAl alloy compressive property grain refining

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Construction and heterologous expression of the di-AFN A_(1) biosynthetic gene cluster in Streptomyces model strains

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Chinese Journal of Natural Medicines 2022年第11期20卷 873-880页

作者： wei weijia WANG Wenzhao LI Chao TANG Yue GUO Zhengyan chen Yihua State Key Laboratory of Microbial Resources Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China College of Life Sciences University of Chinese Academy of SciencesBeijing 100149China Institute of Medicinal Biotechnology Chinese Academy of Medical SciencesBeijing 100050China

Natural cyclohexapeptide AFN A_(1) from Streptomyces alboflavus 313 has moderate antibacterial and antitumor *** artificial designed AFN A_(1) homodimer,di-AFN A_(1),is an antibiotic exhibiting 10 to 150 fold higher biological activities,compared with the ***,the yield of di-AFN A_(1) is very low(0.09±0.03 mg·L^(−1))in the engineered strain Streptomyces alboflavus 313_hmtS(***/313_hmtS),which is not friendly to be genetically engineered for titer improvement of di-AFN A_(1) *** this study,we constructed a biosynthetic gene cluster for di-AFN A_(1) and increased its production through heterologous *** the collection of di-AFN A_(1) biosynthetic genes,the afn genes were located at three sites of *** 313 *** di-AFN A_(1) biosynthetic gene cluster(BGC)was first assembled on one plasmid and introduced into the model strain Streptomyces lividans TK24,which produced di-AFN A_(1) at a titer of 0.43±0.01 mg·L^(−1).To further increase the yield of di-AFN A_(1),the di-AFN A_(1) BGC was multiplied and split to mimic the natural afn biosynthetic genes,and the production of di-AFN A_(1) increased to 0.62±0.11 mg·L^(−1) in *** TK24 by the later ***,different Streptomyces hosts were tested and the titer of di-AFN A_(1) increased to 0.81±0.17 mg·L^(−1),about 8.0-fold higher than that in ***/313_*** heterologous expression of di-AFN A_(1) with a remarkable increased titer will greatly facilitate the following synthetic biological study and drug development of this dimeric cyclohexapeptide.

关键词： Cyclohexapeptide di-AFN A_(1) Titer improvement Heterologous expression Streptomyces host

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Change of pore water near the freezing front during soil freezing: Migration and mechanisms

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Pedosphere 2024年第4期34卷 770-782页

作者： Yajun SHI wei MA Lianhai ZHANG chengsong YANG Fei SHANG cheng chen State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Department of Joint NMR Laboratory for Freeze-Thaw Processes in Soils of State Key Laboratory of Frozen Soil Engineering and Suzhou Niumag Analytical Instrument Corporation Lanzhou 730000China

The formation and growth of segregation ice dominate the frost heave during soil freezing,which is closely related to water *** analyze segregation ice during soil freezing for different soils,a freezing-thawing experiment was conducted with Lanzhou loess(LZL)and Qinghai-Tibet Plateau silty clay(QSC)using a novel layered nuclear magnetic resonance *** LZL freezing,the unfrozen water content first increased and then decreased with decreasing temperature near the freezing front,but decreased with decreasing temperature in other layers,whereas during the freezing of QSC,the unfrozen water content in different layers(including the freezing front)decreased with decreased ***,the increased liquid water near the freezing front during LZL freezing was primarily adsorbed *** addition to the temperature gradient,the squeezing action during soil freezing was another important factor affecting water migration,especially at the early stage of soil ***,which of the two factors,squeezing action and temperature gradient,was the dominant one causing water migration depended on soil *** the early stage of soil freezing,the squeezing action had a significant effect on the water migration of LZL,but no significant effect on that of ***,water accumulation of LZL near the freezing front due to squeezing action at the early stage of freezing limited the formation and growth of segregation *** study provided an improved understanding for ice segregation and water migration during soil freezing.

关键词： freezing-thawing experiment frozen soil nuclear magnetic resonance phase transition segregation ice squeezing action unfrozen water water migration

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Heterogeneous body compositions and all-cause mortality in acute coronary syndrome patients:a ten-year retrospective cohort study

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Journal of Geriatric Cardiology 2024年第5期21卷 534-541页

作者： Guang-zhi LIAO Lin BAI Yu-Yang YE Xue-Feng chen Xin-Ru HU Yong PENG Department of Cardiology West China HospitalSichuan UniversityChengduSichuanChina

BACKGROUND The association of different body components,including lean mass and body fat,with the risk of death in acute coronary syndrome(ACS)patients are *** We enrolled adults diagnosed with ACS at our center between January 2011 and December 2012 and obtained fol-low-up outcomes via telephone *** used restricted cubic splines(RCS)with the Cox proportional hazards model to analyze the associations between body mass index(BMI),predicted lean mass index(LMI),predicted body fat percentage(BF),and the value of LMI/BF with 10-year *** also examined the secondary outcome of death during *** During the maximum 10-year follow-up of 1398 patients,331 deaths(23.6%)occurred,and a U-shaped relationship was found between BMI and death risk(P_(nonlinearity)=0.03).After adjusting for age and history of diabetes,the overweight group(24≤BMI<28 kg/m^(2))had the lowest mortality(HR=0.53,95%CI:0.29-0.99).Predicted LMI and LMI/BF had an inverse linear relationship with a 10-year death risk(P_(nonlinearity)=0.24 and P_(nonlinearity)=0.38,respectively),while an increase in BF was associ-ated with increased mortality(P_(nonlinearity)=0.64).During hospitalization,31 deaths(2.2%)were recorded,and the associations of the indicators with in-hospital mortality were consistent with the long-term outcome *** Our study provides new insight into the“obesity paradox”in ACS patients,highlighting the importance of considering body composition *** LMI and BF may serve as useful tools for assessing nutritional status and predicting the prognosis of ACS,based on their linear associations with all-cause mortality.

关键词： patients mortality coronary

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3D flower-like mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme heterojunction with optimized photothermal-photocatalytic performance

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Green Energy & Environment 2023年第1期8卷 200-212页

作者： Sijia Song Zipeng Xing Ke Wang Huanan Zhao Peng chen Zhenzi Li wei Zhou Department of Environmental Science School of Chemistry and Materials ScienceKey Laboratory of Functional Inorganic Material ChemistryMinistry of Education of the People's Republic of ChinaHeilongjiang UniversityHarbin150080China Shandong Provincial Key Laboratory of Molecular Engineering School of Chemistry and Chemical EngineeringQilu University of Technology(Shandong Academy of Sciences)JinanShandong250353China

3D flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal *** heterojunction with narrow band gap of~1.95 eV extended the photoresponse to near-infrared region,which showed obvious photothermal effect due to the introduction of MoS_(2) with broad spectrum ***_(2) nanosheets were anchored onto the surface of flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2) nanosheets,thereby forming efficient layered heterojunctions,the solar-driven photocatalytic efficiency in degradation of highly toxic dichlorophenol and reduction of hexavalent chromium was improved to 98.5%and 99.2%,which was~4 and 7 times higher than that of the pristine Bi_(4)O_(5)I_(2),*** addition,the photocatalytic hydrogen production rate reached 496.78 μmol h^(-1)g^(-1),which was~6 times higher than that of the pristine Bi_(4)O_(5)I_(2).The excellent photocatalytic performance can be ascribed to the promoted photothermal effect,as well as,the formation of compact Z-scheme layered *** 3D flower-like hierarchical mesoporous structure provided adequate surface active-sites,which was conducive to the mass ***,the high stability of the prepared photocatalyst further promoted its potential practical *** strategy also provides new insights for fabricating layered Zscheme heterojunctions photocatalysts with highly photothermal-photocatalytic efficiency.

关键词： Photocatalysis Z-scheme heterojunction Bi4O5I2 MoS2 Photothermal effect

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Enantioselective Diels-Alder reactions with left-handed G-quadruplex DNA-based catalysts

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Chinese Chemical Letters 2021年第5期32卷 1701-1704页

作者： Kun chen zhiyong He wei Xiong Chun-Jiang Wang Xiang Zhou College of Chemistry and Molecular Sciences Key Laboratory of Biomedical Polymers of Ministry of EducationWuhan UniversityWuhan 430072China

Since the discovery of left-handed G-quadruplex(L-G4)structure formed by natural DNA,there has been a growing interest in its potential *** study utilised it to catalyse enantioselective Diels-Alder reactions,considering its different optical rotation compared to an ordinary *** was determined that when L-G4 was used with a combination of copper(Ⅱ)ions,there was a good enantioselectivity(-52%ee)without further addition of *** further consideration was given by adding G4 ligands,G4 was further stabilised,even obtaining a better enantioselectivity(up to-80%ee).Moreover,when using ligands that have regulatory effects on G4,the ee value can be *** this work,a minimal left-handed G4 was reported.A follow-up study was also con ducted,which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity,but is not so effective as the former *** indicates that a complete G4 structure is relatively conducive to chiral catalysis.

关键词： Diels-Alder reaction Left-handed G-quadruplex Asymmetric catalysis Enantioselectiv ity G-quadruplex ligand

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