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Investigation of Projectile Impact Behaviors of Graphene Aerogel Using Molecular Dynamics Simulations

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 3047-3061页

作者： Xinyu Zhang Wenjie Xia Yang wang liang wang Xiaofeng Liu Department of Engineering Mechanics Shanghai Jiao Tong UniversityShanghai200240China Department of Aerospace Engineering Iowa State UniversityAmesIA50011USA School of Materials Science and Engineering University of Science&Technology BeijingBeijing100083China Zernike Institute for Advanced Materials University of GroningenGroningen9747The Netherlands

Graphene aerogel(GA),as a novel solid material,has shown great potential in engineering applications due to its unique mechanical properties.In this study,the mechanical performance of GA under high-velocity projectile impacts is thoroughly investigated using full-atomic molecular dynamics(MD)simulations.The study results show that the porous structure and density are key factors determining the mechanical response of GA under impact loading.Specifically,the impact-induced penetration of the projectile leads to the collapse of the pore structure,causing stretching and subsequent rupture of covalent bonds in graphene sheets.Moreover,the effects of temperature on the mechanical performance of GA have been proven to be minimal,thereby highlighting the mechanical stability of GA over a wide range of temperatures.Finally,the energy absorption density(EAD)and energy absorption efficiency(EAE)metrics are adopted to assess the energy absorption capacity of GA during projectile penetration.The research findings of this work demonstrate the significant potential of GA for energy absorption applications.

关键词： Graphene aerogel molecular dynamics simulation impact response energy absorption

A stable implicit nodal integration-based particle finite element method(N-PFEM)for modelling saturated soil dynamics

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2172-2183页

作者： liang wang Xue Zhang Jingjing Meng Qinghua Lei Department of Earth Sciences ETH ZürichZürich8092Switzerland Department of Civil Engineering and Industrial Design University of LiverpoolLiverpoolL693BXUK Department of Civil Environmental and Natural Resources EngineeringLuleåUniversity of TechnologyLuleå97187Sweden Department of Earth Sciences Uppsala UniversityUppsala75105Sweden

In this study,we present a novel nodal integration-based particle finite element method(N-PFEM)designed for the dynamic analysis of saturated soils.Our approach incorporates the nodal integration technique into a generalised Hellinger-Reissner(HR)variational principle,creating an implicit PFEM formulation.To mitigate the volumetric locking issue in low-order elements,we employ a node-based strain smoothing technique.By discretising field variables at the centre of smoothing cells,we achieve nodal integration over cells,eliminating the need for sophisticated mapping operations after re-meshing in the PFEM.We express the discretised governing equations as a min-max optimisation problem,which is further reformulated as a standard second-order cone programming(SOCP)problem.Stresses,pore water pressure,and displacements are simultaneously determined using the advanced primal-dual interior point method.Consequently,our numerical model offers improved accuracy for stresses and pore water pressure compared to the displacement-based PFEM formulation.Numerical experiments demonstrate that the N-PFEM efficiently captures both transient and long-term hydro-mechanical behaviour of saturated soils with high accuracy,obviating the need for stabilisation or regularisation techniques commonly employed in other nodal integration-based PFEM approaches.This work holds significant implications for the development of robust and accurate numerical tools for studying saturated soil dynamics.

关键词： Particle finite element method Nodal integration Dynamic saturated media Second-order cone programming(SOCP)

Synthesis of Anti-Pancreatic Cancer Natural Product Majusculamide D and Analogues Reveals a Preliminary Structure-Activity Relationships

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Chinese Journal of Chemistry 2024年第6期42卷 605-610页

作者： Xiuhe Zhao Mengxue Lv Xiaonan Xi Yaxin Lu liang wang Yue Chen The State Key Laboratory of Medicinal Chemical Biology College of PharmacyNankai UniversityTianjin300350 China College of Chemistry Nankai UniversityTianjin300071 China

The total synthesis of majusculamide D(1)was achieved from commercially available materials.In addition,we synthesized eight analogues including three stereoisomers of majusculamide D that differ in the fatty acid chain.Six analogues including a simplified analogue 29 exhibited significant nanomolar-level IC50 values against Panc-1 cells in MTT assays.A preliminary SAR analysis indicated that the hydroxyl group at C10 and C2−C3 unsaturated double bond of majusculamide D were essential in maintaining the high activity against Panc-1 cells and the orientation of C40-Me and C42-Me groups was tolerable.

关键词： Majusculamide D Natural products SAR Anti-pancreatic cancer Lipopentapeptide

Rapid Unconscious Acquisition of Conditioned Fear with Low-Spatial-Frequency but Emotionally Neutral Stimuli

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Research 2024年第1期2023卷 753-762页

作者： Yujie Chen Si Chen Zhongju Sun Xilei Zhang Xiangyong Yuan liang wang Yi Jiang State Key Laboratory of Brain and Cognitive Sciences CAS Center for Excellence in Brain Science and Intelligence TechnologyInstitute of PsychologyChinese Academy of SciencesBeijing 100101China Department of Psychology University of Chinese Academy of SciencesBeijing 100049China Chinese Institute for Brain Research Beijing 102206China CAS Key Laboratory of Mental Health Institute of PsychologyChinese Academy of SciencesBeijing 100101China

It has long been proposed that emotionally“prepared”(i.e.,fear-related)stimuli are privileged in the unconscious acquisition of conditioned fear.However,as fear processing is suggested to highly depend on the coarse,low-spatial-frequency(LSF)components of the fear-related stimuli,it is plausible that LSF may play a unique role in the unconscious fear conditioning even with emotionally neutral stimuli.Here,we provided empirical evidence that,following classical fear conditioning,an invisible,emotionally neutral conditioned stimulus(CS+)with LSF,but not with high spatial frequency(HSF),can rapidly elicit stronger skin conductance responses(SCRs)and larger pupil diameters than its CS−counterpart.In comparison,consciously perceived emotionally neutral CS+with LSF and HSF elicited comparable SCRs.Taken together,these results support that the unconscious fear conditioning does not necessarily entail emotionally prepared stimuli but prioritizes LSF information processing and highlight the crucial distinctions between the unconscious and the conscious fear learning.These findings not only coincide with the postulation that a rapid,spatial-frequency-dependent subcortical route is engaged in unconscious fear processing but also suggest the existence of multiple routes for conscious fear processing.

关键词： neutral necessarily diameters

Design of Support Effect in the Catalytic Application of Ligand-Protect Gold Clusters

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Chinese Journal of Chemistry 2024年第1期42卷 73-86页

作者： Shuohao Li Shenguang Fu Yuqing Gong Nuojie Wu Lei wang liang wang School of Safety Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China Schoolof Chemistry and Chemical Engineering Yangzhou UniversityYangzhouJiangsu 225009 Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization China University of Mining and Technology XuzhouJiangsu 221008China

Ligand-protected gold(Au_(n))clusters sometimes need the removal of organic ligands to expose more active sites and reduce steric hindrance in catalytic reactions,and large amount of organic and inorganic materials usually need to be employed as supports to anchor Aun clusters through different interaction mechanisms.Whereas,less comprehensive summaries have been provided about the crucial contribution of various supports to the catalytic performance of the supported Aun clusters.Herein,this review firstly summarizes synthesis methods(e.g.,impregnation and encapsulation processes)for the supported Aun cluster catalysts,and then mainly points out specific contributions of support effect in a great diversity of catalytic reactions,as well as deep interaction mechanisms.Besides,opportunities and challenging issues will be stated towards supported Aun clusters,in terms of improving catalytic performance and structural stability of Aun clusters inthedemand of catalysis.

关键词： Gold clusters Synthesis Support effect Catalytic performance Interaction

Comparison of various prediction models in the effect of laparoscopic sleeve gastrectomy on type 2 diabetes mellitus in the Chinese population 5 years after surgery

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Chinese Medical Journal 2024年第3期137卷 320-328页

作者： Chengyuan Yu liang wang Guangzhong Xu Guanyang Chen Qing Sang Qiqige Wuyun Zheng wang Chenxu Tian Nengwei Zhang Surgery Centre of Diabetes Mellitus Peking University Ninth School of Clinical MedicineBeijing 100038China Department of Surgery Beijing Shijitan HospitalCapital Medical UniversityBeijing 100038China

Background:The effect of bariatric surgery on type 2 diabetes mellitus(T2DM)control can be assessed based on predictive models of T2DM remission.Various models have been externally verified internationally.However,long-term validated results after laparoscopic sleeve gastrectomy(LSG)surgery are lacking.The best model for the Chinese population is also unknown.Methods:We retrospectively analyzed Chinese population data 5 years after LSG at Beijing Shijitan Hospital in China between March 2009 and December 2016.The independent t-test,Mann–Whitney U test,and chi-squared test were used to compare characteristics between T2DM remission and non-remission groups.We evaluated the predictive efficacy of each model for longterm T2DM remission after LSG by calculating the area under the curve(AUC),sensitivity,specificity,Youden index,positive predictive value(PPV),negative predictive value(NPV),and predicted-to-observed ratio,and performed calibration using Hosmer–Lemeshow test for 11 prediction models.Results:We enrolled 108 patients,including 44(40.7%)men,with a mean age of 35.5 years.The mean body mass index was 40.3±9.1 kg/m^(2),the percentage of excess weight loss(%EWL)was(75.9±30.4)%,and the percentage of total weight loss(%TWL)was(29.1±10.6)%.The mean glycated hemoglobin A1c(HbA1c)level was(7.3±1.8)%preoperatively and decreased to(5.9±1.0)%5 years after LSG.The 5-year postoperative complete and partial remission rates of T2DM were 50.9%[55/108]and 27.8%[30/108],respectively.Six models,i.e.,"ABCD",individualized metabolic surgery(IMS),advanced-DiaRem,DiaBetter,Dixon et al’s regression model,and Panunzi et al’s regression model,showed a good discrimination ability(all AUC>0.8).The"ABCD"(sensitivity,74%;specificity,80%;AUC,0.82[95%confidence interval[CI]:0.74–0.89]),IMS(sensitivity,78%;specificity,84%;AUC,0.82[95%CI:0.73–0.89]),and Panunzi et al’s regression models(sensitivity,78%;specificity,91%;AUC,0.86[95%CI:0.78–0.92])showed good discernibility.In the Hosmer–Lemeshow goodness-of-fit test,except for DiaRem(P<0.01),Di

关键词： Type 2 diabetes mellitus Risk prediction models External validation Sleeve gastrectomy Bariatric surgery

Carbon emission reduction: Contribution of geothermal energy and practice in China

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China Geology 2024年第1期7卷 161-164页

作者： liang wang Li-qiong Jia Natural Resources Integrated Survey Command Center China Geological SurveyMinistry of Natural ResourcesBeijing 100055China Development and Research Center China Geological SurveyMinistry of Natural ResourcesBeijing 100037China

As a kind of natural energy from the earth’s interior,geothermal energy is characterized by large reserve,wide distribution,good stability,high utilization coefficient,and positive effects of energy-saving and emission-reduction.It is of great significance for promoting green and low-carbon energy transition,reducing greenhouse gas emission,and achieving global climate goals and sustainable economic development.Hence,it has been highly recognized and valued by lots of countries around the world,and has become one of the most important clean energy sources that countries are accelerating to develop and utilize.The potential of the global geothermal energy resource is estimated to be 1.25×1027 J,equivalent to 4.27×10^(16) t of standard coal,among which the geothermal resource between 0 km and 5 km is 1.45×10^(26) J,equivalent to 4.95×1015 t of standard coal(China Geological Survey,2018).

关键词： energy utilize interior

A Multi-AGV Routing Planning Method Based on Deep Reinforcement Learning and Recurrent Neural Network

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1720-1722页

作者： Yishuai Lin Gang Hu liang wang Qingshan Li Jiawei Zhu the School of Computer Science and Technology Xidian UniversityXi’an 710000China Suzhou Mingyi Intelligence Warehousing Information Technology Co. Ltd.Kunshan 215300China the School of Information Engineering Chang’an UniversityXi’an 710000China

Dear Editor,This letter presents a multi-automated guided vehicles(AGV) routing planning method based on deep reinforcement learning(DRL)and recurrent neural network(RNN), specifically utilizing proximal policy optimi... 详细信息

关键词： network AGV Deep

A Secure Communicating While Jamming Approach for End-to-End Multi-Hop Wireless Communication Network

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Chinese Journal of Electronics 2024年第3期33卷 833-846页

作者： Xiao MA Dan LI liang wang Weijia HAN Nan ZHAO School of Physics and Information Technology Shaanxi Normal University Beijing Aerospace Science and Industry Century Satellite Hi-tech Co. Ltd.Xi'an Branch School of Computer Science Shaanxi Normal University School of Telecommunications Engineering Xidian University

With the rapid development of wireless communications,cellular communication and distributed wireless network are fragile to eavesdropping due to distributed users and transparent communication.However,to adopt bigger transmit power at a given area to interfere potential eavesdroppers not only incurs huge energy waste but also may suppresses regular communication in this area.To this end,we focus on secure communication in multi-hop wireless communication network,and propose two communicating while jamming schemes for secure communication in presence of potential eavesdroppers for the narrow band and broad band point-to-point(P2P) systems respectively with the aid of artificial noise transmitted by a chosen cooperative interferer.Furthermore,to achieve the end-to-end(E2E) multi-hop secure communication,we devise the secure network topology discovering scheme.via constructing a proper network topology with at least one proper node as the cooperative interferer in each hop,and then propose the secure transmission path planning scheme to find an E2E secure transmission route from source to destination,respectively.Experiments on the wireless open-access research platform demonstrate the feasibility of the proposed schemes.Besides,simulations results validate that the proposed schemes can achieve better performance compared with existing methods in both the P2P communication case and E2E multi-hop communication network scenario.

关键词： Wireless communication Network topology Law Simulation Wireless networks Noise Spread spectrum communication