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Bismuth-free Mg_(3)Sb_(2) with enhanced room-temperature thermoelectric and mechanical properties

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Journal of Materiomics 2024年第5期10卷 1101-1108页

作者： jie song Peng Luo Hailong sun Hezhang Li Chao Wang Yi Niu jing Jiang Clean Energy Materials and Engineering Center State Key Laboratory of Electronic Thin Films and Integrated DevicesSchool of Electronic Science and EngineeringUniversity of Electronic Science and Technology of ChinaChengdu611731China The State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing100084China

Thermoelectric materials are competitive candidates for special cooling ***_(3)Sb_(2)-based materials consisting of inexpensive ingredients have profound thermoelectric *** present,alloying with Mg_(3)Bi_(2) is the most effective approach to optimize the thermoelectric properties of Mg_(3)Sb_(2)-based ***,the extremely low abundance of bismuth in the crust contradicts its economic *** this work,the ZrO_(2) micro-particles were separated into the Mg_(3.2)Sb_(1.99)Te_(0.01).The doping effect of Zr atoms at Mg sites increased the electrical conductivity,and the combined secondary phase lowered the lattice thermal *** acceptable degradation in the Seebeck coefficient,the sample combined with 5%(in mass)ZrO_(2) exhibited a dimensionless figure of merit(zT)of 0.49 and a power factor of 2.7 mW·m^(−1)·K^(−2) near room *** average zT in the range from 300 K to 500 K reached 0.8,on par with the Mg_(3)Sb_(2) single bond Mg_(3)Bi_(2) ***,the compressive and bending strengths reach 669 MPa and 269 MPa,respectively,far superior to the common room-temperature *** secondary phase showed a surprising and uncostly promotion of the Mg_(3)Sb_(2)-based thermoelectric materials,impelling the realization of its commercial application.

关键词： Mg_(3)Sb_(2)-Mg_(3)Bi_(2)alloy Secondary phase Room-temperature thermoelectric properties Mechanical properties Inexpensive ingredients

Gas film/regenerative composite cooling characteristics of the liquid oxygen/liquid methane (LOX/LCH4) rocket engine

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2024年第8期25卷 631-649页

作者： Xinlin LIu Jun sun Zhuohang JIANG Qinglian LI Peng CHENG jie song Science and Technology on Scramjet Laboratory College of Aerospace Science and EngineeringNational University of Defense TechnologyChangsha 410073China

The thermal protection of rocket engines is a crucial aspect of rocket engine *** this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber was investigated.A gas film/regenerative composite cooling model was developed based on the Grisson gas film cooling efficiency formula and the one-dimensional regenerative cooling *** accuracy of the model was validated through experiments conducted on a 6 kg/s level gas film/regenerative composite cooling thrust ***,key parameters related to heat transfer performance were *** results demonstrate that the model is sufficiently accurate to be used as a preliminary design *** temperature rise error of the coolant,when compared with the experimental results,was found to be less than 10%.Although the pressure drop error is relatively large,the calculated results still provide valuable guidance for heat transfer *** addition,the performance of composite cooling is observed to be superior to regenerative *** the gas film flow rate results in higher cooling efficiency and a lower gas-side wall ***,the position at which the gas film is introduced greatly impacts the cooling *** optimal introduction position for the gas film is determined when the film is introduced from a single row of *** optimal introduction position results in a more uniform wall temperature distribution and reduces the peak ***,it is observed that a double row of holes,when compared to a single row of holes,enhances the cooling effect in the superposition area of the gas film and further lowers the gas-side wall *** results provide a basis for the design of gas film/regenerative composite cooling systems.

关键词： Liquid oxygen/liquid methane(LOX/LCH4)rocket engine Gas film cooling Regenerative cooling Heat transfer characteristics

Hybrid HMX multi-level assembled under the constraint of 2D materials with efficiently reduced sensitivity and optimized thermal stability

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Defence Technology（防务技术） 2024年第9期39卷 123-132页

作者： Xiaomin song Longjin Huang Rufang Peng Qi Huang Jinjiang Xu jie sun Institute of Chemical Materials China Academy of Engineering PhysicsMianyang621900China State Key Laboratory of Environment-friendly Energy Materials School of Materials Science and EngineeringSouthwest University of Science and TechnologyMianyang621010China

The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive ***,screening suitable coating agents to enhance the interfacial effect to obtain high-energy and low-sensitivity explosives has long been a major *** this work,HMX-PEI/rGO/g-C_(3)N_(4)(HPrGC)composites were innovatively prepared by a multi-level coating strategy of two-dimensional graphite rGO and g-C_(3)N_(4).The g-C_(3)N_(4) used for desensitization has a richπ-conjugated system and shows outstanding ability in reducing friction *** hierarchical structure of HPrGC formed by electrostatic self-assembly andπ-πstacking can effectively dissipate energy accumulation under heat and mechanical stimulation through structural evolution,thus exhibiting a prominent synergistic desensitization effect on *** results show that rGO/gC_(3)N_(4) coating has no effect on the crystal structure and chemical structure of *** importantly,the perfect combination of g-C_(3)N_(4) and rGO endows HPrGC with enhanced thermal stability and ideal mechanical sensitivity(IS:21 J,FS:216 N).Obviously,the new fabrication of HPrGC enriches the variety of desensitizer materials and helps to deepen the understanding of the interaction between explosives and coatings.

关键词： HMX-PEI/rGO/g-C_(3)N_(4) Electrostatic self-assembly π-πstacking Synergistic desensitization

Correlation between abdominal computed tomography signs and postoperative prognosis for patients with colorectal cancer

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World Journal of Gastrointestinal Surgery 2024年第7期16卷 2145-2156页

作者： Shao-Min Yang jie-Mei Liu Rui-Ping Wen Yu-Dong Qian jing-Bo He jing-song sun Department of Radiology Xingtan Hospital Affiliated to Shunde Hospital of Southern Medical UniversityFoshan 528315Guangdong ProvinceChina Department of Rehabilitation Medicine Shunde HospitalSouthern Medical UniversityFoshan 528399Guangdong ProvinceChina Department of Radiology Lecong Hospital of ShundeFoshan 528315Guangdong ProvinceChina Department of ultrasound Lecong Hospital of ShundeFoshan 528315Guangdong ProvinceChina

BACKGROuND Patients with different stages of colorectal cancer(CRC)exhibit different abdominal computed tomography(CT)***,the influence of CT signs on CRC prognosis must be *** To observe abdominal CT signs in patients with CRC and analyze the correlation between the CT signs and postoperative *** The clinical history and CT imaging results of 88 patients with CRC who underwent radical surgery at Xingtan Hospital Affiliated to Shunde Hospital of Southern Medical university were retrospectively *** and multivariate Cox regression analyses were used to explore the independent risk factors for postoperative death in patients with *** three-year survival rate was analyzed using the Kaplan-Meier curve,and the correlation between postoperative survival time and abdominal CT signs in patients with CRC was analyzed using Spearman correlation *** For patients with CRC,the three-year survival rate was 73.86%.The death group exhibited more severe characteristics than the survival group.A multivariate Cox regression model analysis showed that body mass index(BMI),degree of periintestinal infiltration,tumor size,and lymph node CT value were independent factors influencing postoperative death(Pup had a low three-year survival rate(log-rankχ2=66.487,11.346,12.500,and 27.672,respectively,Purvival time of CRC patients was negatively correlated with BMI,degree of periintestinal infiltration,tumor size,lymph node CT value,mean tumor long-axis diameter,and mean tumor short-axis diameter(r=-0.559,0.679,-0.430,-0.585,-0.425,and-0.385,respectively,Pue,and mean tumor short-axis diameter(r=0.303,0.431,and 0.437,respectively,PuSION The degree of periintestinal infiltration,tumor size,and lymph node CT value are c

关键词： Colorectal cancer Abdominal Computed tomography signs Radical surgery Prognosis Correlation

Bio-inspired barnacle cement coating of biodegradable magnesium alloy for cerebrovascular application

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Rare Metals 2024年第10期43卷 5164-5185页

作者： Hang Li Fei Wang Xiao-jing sun Liu-jie Qi jing-An Li Mujahid Iqbal Shao-Kang Guan School of Material Science and Engineering Zhengzhou University Henan Key Laboratory of Advanced Magnesium Alloy&Key Laboratory of Materials Processing and Mold (Ministry of Education) Zhengzhou University Department of Physics University of Agriculture Faisalabad

Ischemic stroke is increasing worldwide, and stent intervention has gradually become one of the effective treatments. Owing to its good mechanical properties and biocompatibility, biodegradable Mg-Zn-Y-Nd alloy(ZE21B) has good application prospects in vascular ***, too fast degradation and delayed endothelialization are the bottleneck problem to limit its further application. In this study, the bio-inspired coating barnacle cement cp19k is constructed on ZE21B surface through electrostatic spraying to improve the corrosion resistance and pro-endothelialization ability. The coating was evaluated through electrochemistry, static immersion corrosion,in vitro blood experiments and cell experiments. Cp19k effectively improved the corrosion resistance of the substrate ZE21B, reduced the degradation rate, improved endothelial cell proliferation and migration capabilities,inhibited smooth muscle cells proliferation and regulated contractile phenotype, inhibited macrophage adhesion,regulated macrophage M2 phenotype, and reduced the expression of inflammatory factor of TNF-a and inhibited fibroplasia in vivo. Our data indicated that the barnacle cement cp19k coating had potential application on the surface modification of Mg alloy cerebrovascular stent.

关键词： Barnacle cement cp19k Biodegradable magnesium alloy Cerebrovascular stent M2 phenotype Pro-endothelialization

Health risk assessment of trace metal(loid)s in agricultural soils based on Monte Carlo simulation coupled with positive matrix factorization model in Chongqing, southwest China

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Journal of Mountain Science 2024年第1期21卷 100-112页

作者： MA jie CHu Lijuan sun jing WANG Shenglan GE Miao DENG Li Chongqing Ecological and Environmental Monitoring Center Chongqing 401147China Key Laboratory of Organic Pollutants in Environmental Chemical Behavior and Ecological Toxicology of Chongqing Chongqing 401147China Department of Pediatrics Chongqing Health Center for Women and ChildrenChongqing 401147China Department of Pediatrics Women and Children’s Hospital of Chongqing Medical UniversityChongqing 401147China

This study aimed to investigate the pollution characteristics, source apportionment, and health risks associated with trace metal(loid)s(TMs) in the major agricultural producing areas in Chongqing, China. We analyzed the source apportionment and assessed the health risk of TMs in agricultural soils by using positive matrix factorization(PMF) model and health risk assessment(HRA) model based on Monte Carlo simulation. Meanwhile, we combined PMF and HRA models to explore the health risks of TMs in agricultural soils by different pollution sources to determine the priority control factors. Results showed that the average contents of cadmium(Cd), arsenic (As), lead(Pb), chromium(Cr), copper(Cu), nickel(Ni), and zinc(Zn) in the soil were found to be 0.26, 5.93, 27.14, 61.32, 23.81, 32.45, and 78.65 mg/kg, respectively. Spatial analysis and source apportionment analysis revealed that urban and industrial sources, agricultural sources, and natural sources accounted for 33.0%, 27.7%, and 39.3% of TM accumulation in the soil, respectively. In the HRA model based on Monte Carlo simulation, noncarcinogenic risks were deemed negligible(hazard index ults. The relationship between TMs, their sources, and health risks indicated that urban and industrial sources were primarily associated with As, contributing to 75.1% of carcinogenic risks and 55.7% of non-carcinogenic risks, making them the primary control factors. Meanwhile, agricultural sources were primarily linked to Cd and Pb, contributing to 13.1% of carcinogenic risks and 21.8% of non-carcinogenic risks, designating them as secondary control factors.

关键词： Monte Carlo simulation Health risk assessment Trace metal(loid)s Positive matrix factorization Agricultural soils

Interfacial charge redistribution to promote the catalytic activity of Vs-CoP-CoS_(2)/C n-n heterojunction for oxygen evolution

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Chinese Chemical Letters 2024年第2期35卷 611-616页

作者： Jiawen sun Hui Xue jing sun Niankun Guo Tianshan song Yi-Ru Hao Qin Wang College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China

Modulating surface charge redistribution based on interface and defect engineering has been considered as a resultful means to boost electrocatalytic ***,the mechanism of synergistic regulation of heterojunction and vacancy defects remains ***,a Vs-CoP-CoS_(2)/C n-n heterojunction with sulfur vacancies is successfully constructed,which manifests superior electrocatalytic activity for oxygen evolution,as demonstrated by a low overpotential of 170 mV to reach 10 mA/cm^(2).The experimental results and density functional theory calculations testify that the outstanding OER performance of Vs-CoP-CoS_(2)/C heterojunction is owed to the synergistic effect of sulfur vacancies and built-in electric field at n-n heterogeneous interface,which accelerates the electron transfer,induces the charge redistribution,and regulates the adsorption energy of active intermediates during the *** study affords a promising means to regulate the electrocatalytic performance by the construction of heterogeneous interfaces and defects,and in-depth explores the synergistic mechanisms of n-n heterojunction and vacancies.

关键词： Charge redistribution n-n Heterojunction Built-in electric field Sulfur vacancy Oxygen evolution reaction

Transient Damping of Virtual Synchronous Generator for Enhancing Synchronization Stability during Voltage Dips

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 143-151页

作者： Shitao sun Yu Lei Guowen Hao Yi Lu Jindong Liu Zhaoxin song jie Zhang North China Electric Power Research Institute Co. Ltd.Beijing 100045China State Grid Xinyuan Co. Ltd.Beijing 100761China Hebei Fengning Pumped Storage Energy Co.Ltd. Chengde 068350China

Virtual synchronous generators(VSGs)are widely introduced to the renewable power generation,the variablespeed pumped storage units,and so on,as a promising gridforming *** is noted that VSGs can provide virtual inertia for frequency support,but the larger inertia would worsen the synchronization stability,referring to keeping synchronization with the grid during voltage ***,this paper presents a transient damping method of VSGs for enhancing the synchronization stability during voltage *** is revealed that the loss of synchronization(LOS)of VSGs always accompanies with the positive frequency deviation and the damping is the key factor to remove LOS when the equilibrium point *** order to enhance synchronization stability during voltage dips,the transient damping is proposed,which is generated by the frequency deviation in active power ***,the proposed method can realize seamless switching between normal state and grid ***,detailed control design for transient damping gain is given to ensure the synchronization stability under different inertia requirements during voltage ***,the experimental results are presented to validate the analysis and the effectiveness of the improved transient damping method.

关键词： Virtual synchronous generator(VSG) Transient damping Synchronization stability Voltage dips

Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

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Nuclear Science and Techniques 2024年第3期35卷 84-95页

作者： Lei Peng Yong-jie sun jing-Yi Shi Yi-Fei Liu Shang-Ming Chen Liu-Liu Li State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion *** order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics *** results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile *** atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation ***,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at *** bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation ***,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

关键词： Helium bubble Grain boundary Embrittlement Reduced activation ferritic martensitic steel Molecular dynamics Bain path