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Biomedical and Environmental Sciences 2024年第5期37卷 526-530页

作者： HUANG Shi Ting li shang yuan li Xin Yu ZHU Ying ZHU lin ZHANG Jia Yan ZHAO Yan Sheng DAGliA Maria XIAO Xiang BAI Juan School of Food and Biological Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina Department of Pharmacy University of Napoli FedericoⅡVia D.Montesano 4980131 NaplesItaly International Research Center for Food Nutrition and Safety Jiangsu UniversityZhenjiang 212013JiangsuChina

Bitter melon(Momordica Charania L.),a member of the Cucurbitaceae family,is widely distributed across tropical and subtropical ***,an important functional component of bitter melon,has been proven to exert hypoglycemic effects similarly to insulin,and also possesses lipid-lowering properties inhibiting preadipocyte differentiation and fat synthesis^([1]).

关键词： melon Momordica subtropical

Improving hydrogen storage thermodynamics and kinetics of Ce-Mg-Ni-based alloy by mechanical milling with TiF_(3)

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Journal of Magnesium and Alloys 2024年第4期12卷 1593-1607页

作者： Hongwei shang Wei Zhang Xin Wei Yaqin li Zeming yuan Jun li Yanghuan Zhang School of Mechanical and Electrical Engineering Chuzhou UniversityChuzhou 239000China Department of Functional Material Research Central Iron and Steel Research InstituteNo.76 Xueyuannan RoadHaidian DistrictBeijing 100081China Key Laboratory of Integrated Exploitation of Bayan-Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010China China Rare Earth New Material(Weishan)Co. Ltd.Jining 277600China

Mg-based hydrides are too stable and the kinetics of hydrogen absorption and desorption is not *** efficient way to improve these shortcomings is to employ reactive ball milling to synthesize the nanocomposite materials of Mg and *** this experiment,TiF_(3)was selected as an additive,and the mechanical milling method was employed to prepare the experimental *** alloys used in this experiment were the as-cast Ce_(5)Mg_(85)Ni_(10),as-milled Ce_(5)Mg_(85)Ni_(10)and Ce_(5)Mg_(85)Ni_(10)+3 wt.%*** phase transformation,structural evolution,isothermal and non-isothermal hydrogenation and dehydrogenation performances of the alloys were inspected by XRD,SEM,TEM,Sievert apparatus,DSC and *** revealed that nanocrystalline appeared in the as-milled *** with the as-cast alloy,ball milling made the particle dimension and grain size decrease dramatically and the defect density increase *** addition of TiF_(3)made the surface of ball milling alloy particles markedly coarser and more *** milling and adding TiF_(3)distinctly improved the activation and kinetics of the ***,ball milling along with TiF_(3)can decrease the onset dehydrogenation temperature of Mg-based hydrides and slightly ameliorate their thermodynamics.

关键词： Mg-based hydrides TiF_(3) Ball milling Thermodynamics Kinetics

The origin and evolution of Earth's nitrogen

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National Science Review 2024年第06期11卷 56-75页

作者： yuan li State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sciences Bayerisches Geoinstitut Universit?t Bayreuth

Nitrogen is a vital element for life on Earth. Its cycling between the surface(atmosphere + crust) and the mantle has a profound influence on the atmosphere and climate. However, our understanding of the origin and evolution of Earth's nitrogen is still incomplete. This review presents an overview of the current understanding of Earth's nitrogen budget and the isotope composition of different reservoirs, laboratory constraints on deep nitrogen geochemistry, and our understanding of the origin of Earth's nitrogen and the deep nitrogen cycle through plate subduction and volcanism. The Earth may have acquired its nitrogen heterogeneously during the main accretion phase, initially from reduced, enstatite-chondrite-like impactors,and subsequently from increasingly oxidized impactors and minimal CI-chondrite-like materials. like Earth's surface, the mantle and core are also significant nitrogen reservoirs. The nitrogen abundance and isotope composition of these three reservoirs may have been fundamentally established during the main accretion phase and have been insignificantly modified afterwards by the deep nitrogen cycle, although there is a net nitrogen ingassing into Earth's mantle in modern subduction zones. However, it is estimated that the early atmosphere of Earth may have contained ～1.4 times the present-day atmospheric nitrogen(PAN),with ～0.4 PAN being sequestered into the crust via biotic nitrogen fixation. In order to gain a better understanding of the origin and evolution of Earth's nitrogen, directions for future research are suggested.

关键词： nitrogen isotopes silicate Earth atmosphere magma ocean

Impact of the Political Risk on Food Reserve Ratio:Evidence Across Countries

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Journal of Systems Science & Complexity 2024年第5期37卷 2071-2103页

作者： XING Kai li shang YANG Xiaoguang School of Economics&Management Nanchang UniversityNanchang330031China Department of Statistics and Data Science National University of Singapore119077Singapore Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100190China

Using an unbalanced panel data covering 75 countries from 1991 to 2019,the authors explore how the political risk impacts on food reserve *** empirical findings show that an increasing political risk negatively affects food reserve ratio,and the same effects hold for both internal risk and external ***,the authors find that the increasing external or internal risks both negatively affect food production and food exports,but external risk does not significantly impact food imports and it positively impacts food consumption,while internal risk negatively impacts food imports and food *** results suggest that most governments have difficulty raising subsequent food reserve ratios in face of an increasing political risk,no matter if it is an internal risk or an external risk although the mechanisms behind the impacts are different.

关键词： External risk food reserve ratio internal risk political risk

Dynamic modeling and RBF neural network compensation control for space flexible manipulator with an underactuated hand

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Chinese Journal of Aeronautics 2024年第3期37卷 417-439页

作者： Dongyang shang Xiaopeng li Meng YIN Fanjie li School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China

In space operation,flexible manipulators and gripper mechanisms have been widely used because of light weight and ***,the vibration caused by slender structures in manipulators and the parameter perturbation caused by the uncertainty derived from grasping mass variation cannot be *** existence of vibration and parameter perturbation makes the rotation control of flexible manipulators difficult,which seriously affects the operation accuracy of ***’s more,the complex dynamic coupling brings great challenges to the dynamics modeling and vibration *** solve this problem,this paper takes the space flexible manipulator with an underactuated hand(SFMUH)as the research *** dynamics model considering flexibility,multiple nonlinear elements and disturbance torque is established by the assumed modal method(AMM)and Hamilton’s principle.A dynamic modeling simplification method is proposed by analyzing the nonlinear ***’s more,a sliding mode control(SMC)method combined with the radial basis function(RBF)neural network compensation is ***,the control law is designed using a saturation function in the control method to weaken the chatter *** the help of neural networks to identify the uncertainty composition in the SFMUH,the tracking accuracy is *** results of ground control experiments verify the advantages of the control method for vibration suppression of the SFMUH.

关键词： Space flexible manipulator RBF neural network Underactuated hand Dynamic models Model simplification

Atomistic understanding of rough surface on the interfacial friction behavior during the chemical mechanical polishing process of diamond

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Friction 2024年第6期12卷 1119-1132页

作者： Song yuan Xiaoguang GUO Hao WANG Renke KANG shang GAO State Key Laboratory of High-performance Precision Manufacturing Dalian University of TechnologyDalian 116024China

The roughness of the contact surface exerts a vital role in *** is still a significant challenge to understand the microscopic contact of the rough surface at the atomic ***,the rough surface with a special root mean square(RMS)value is constructed by multivariate Weierstrass–Mandelbrot(W–M)function and the rubbing process during that the chemical mechanical polishing(CMP)process of diamond is mimicked utilizing the reactive force field molecular dynamics(ReaxFF MD)*** is found that the contact area A/A0 is positively related with the load,and the friction force F depends on the number of interfacial bridge *** the surface roughness will increase the friction force and friction *** model with low roughness and high lubrication has less friction force,and the presence of polishing liquid molecules can decrease the friction force and friction *** RMS value and the degree of damage show a functional relationship with the applied load and lubrication,i.e.,the RMS value decreases more under larger load and higher lubrication,and the diamond substrate occurs severer damage under larger load and lower *** work will generate fresh insight into the understanding of the microscopic contact of the rough surface at the atomic level.

关键词： diamond random roughness reactive force field molecular dynamics(ReaxFF MD) friction Weierstrass-Mandelbrot(W-M)function chemical mechanical polishing(CMP)

Tough Polymeric Hydrogels Based on Amino Acid Derivative Mediated Dynamic Metal Coordination Bonds

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Chinese Journal of Polymer Science 2024年第10期42卷 1578-1588,I0014页

作者： Meng li Meng-yuan Zhang Wu-Xuan Lei Zhu-Ting Lv Qing-Hua shang Zheng Zhao Jiang-Tao li Yi-Long Cheng Engineering Research Center of Energy Storage Materials and Devices Ministry of EducationSchool of ChemistryXi’an Jiaotong UniversityXi’an710049China Polymer Materials&Engineering Department School of Materials Science&Engineering Chang’an UniversityXi’an710064China School of Electrical Engineering Xi’an Jiaotong UniversityXi’an710049China Department of Nuclear Medicine the First Affiliated Hospital of ChinaXi’an Jiaotong UniversityXi’an710049China

Abstract The development of physically crosslinked hydrogels with excellent mechanical and sensing properties is of importance for expanding the practical applications of intelligent soft hydrogel ***,after copolymerization of hydroxyl-containing amino acid derivative N-acryloyl serine(ASer)with acrylamide(AM),we introduce Zr4+through an immersion strategy to construct metal ion-toughened non-covalent crosslinked hydrogels(with tensile strength of up to 5.73 MPa).It is found that the synergistic coordination of hydroxyl and carboxyl groups with Zr^(4+)substantially increases the crosslinking density of the hydrogels,thereby imparting markedly superior mechanical properties compared to hydroxyl-free Zr^(4+)-crosslinked hydrogels,such as N-acryloyl alanine(AAla)copolymerized with AM hydrogels(with tensile strength of 2.98 MPa)Through the adjustment of the composition of the copolymer and the density of coordination bonds,the mechanical properties of the hydrogels can be modulated over a wide ***,due to the introduction of metal ions and the dynamic nature of coordination bonds,the hydrogels also exhibit excellent sensing performance and good self-recovery properties,paving the way for the development of flexible electronic substrates with outstanding comprehensive performances.

关键词： Hydrogel Amino acid Metal coordination Mechanical performance Flexible sensor

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铜片止水一次性成型新工艺设计与应用

广东水利电力职业技术学院学报 2024年第3期22卷 9-13页

作者：张艳杨正策杨韡韡卢文华沙天松李尚元贵州水利水电职业技术学院贵阳551400 贵州水利实业有限公司贵阳550000

混凝土面板堆石坝以上游薄层混凝土面板作为主要防渗结构。铜止水对于控制混凝土面板接缝渗漏起着至关重要的作用,其制作与安装质量直接影响防渗效果。在贵州惠水平寨水库混凝土面板堆石坝施工中,采用自主研发加工设备将铜片加工成型,... 详细信息

混凝土面板堆石坝以上游薄层混凝土面板作为主要防渗结构。铜止水对于控制混凝土面板接缝渗漏起着至关重要的作用,其制作与安装质量直接影响防渗效果。在贵州惠水平寨水库混凝土面板堆石坝施工中,采用自主研发加工设备将铜片加工成型,自动插入橡胶棒,用密封胶固定后将加工好的铜止水快速铺装到堆石坝体的斜坡面上。改进后的止水铜片连续加工工艺显著减少了焊缝,一机可加工多种尺寸,降低了施工和运输成本,加快了施工进度,提高了施工质量,最大限度降低了高坡作业时的事故风险。

关键词：混凝土面板堆石坝止水铜片连续加工技术设计与推广应用

Robustness of the octupole collectivity in 144Ba within the cranking covariant density functional theory in 3D lattice

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Nuclear Science and Techniques 2024年第8期35卷 124-131页

作者： Ze‑Kai li yuan‑yuan Wang Mathematics and Physics Department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071000China

The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice *** reduced B(E3)transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole *** available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3)are well ***,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h).

关键词： Octupole collectivity Cranking covariant density functional theory Rotational spectrum Electric transitional probabilities

Revealing effect of Al content on oxidation of novel Co-Cr-Nb-W carbide-strengthened superalloy

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Rare Metals 2024年第9期43卷 4521-4534页

作者： Chen ling shang-Ping li Jie Hou He-li Luo Central Iron&Steel Research Institute Beijing 100081China Beijing GAONA Materials&Technology Co. Ltd.Beijing 100081China

The high-temperature oxidation behavior of novel Co-Cr-Nb-W carbide-strengthened wear-resistance alloys with different Al contents(1wt%,2wt%and 3wt%)at 950,1000 and 1050℃was thoroughly investigated by scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy and field emission electron probe *** porous property of NbC in-situ oxidation products(Nb_(2)O_(5),Co Nb_(2)O_(6)and Co_(4)Nb_(2)O_(9))induces a multi-layered oxide scale with micropores and ***-Cr-Nb-W alloy with 1 wt%Al undergoes catastrophic oxidation and spalling above 1000℃.The outward transportation of Cr and Co is effectively restrained by a continuous Al_(2)O_(3)scale formed around NbC in-situ oxidation region when Al content reaches 3 wt%.The β-Co Al in Co-Cr-Nb-W alloy with 3 wt%Al has an oxidation priority over eutectic carbides and the alloy matrix which are both enriched with Cr,thereby preventing the formation of Cr-depletion area and improving the self-healing ability of the oxide film.A slight change in Al content has a remarkable influence on the cooperative effect of Al and Cr and multiplies the antioxidant capacity of Co-Cr-Nb-W alloy above 1000℃.

关键词： High-temperature oxidation behavior Oxidation kinetics Superalloy Wear-resistant alloy Microstructure