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Journal of Hydrodynamics 2024年第2期36卷 219-231页

作者： Chen Geng Zhao-hui Qian Ke-xin zheng Wei-xiang Ye Xian-wu Luo State Key Laboratory of Hydroscience cand Engineering Deparment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China

In the present paper,the unsteady cavitating turbulent flow over the twisted NACA66 hydrofoil is investigated based on an modified shear stress transfer k-ωpartially averaged Navier-Stokes(MSST PANS)model,i.e.,new MSST PANS(NMSST PANS)model,where the production term of kinetic energy in the turbulence model is modified with *** with the experimental data,cavitation evolution and its characteristic frequency are satisfactorily predicted by the proposed NMSST PANS *** is revealed that the interaction among the main flow,the reentrant jets,and sheet cavitation causes the formation of the primary shedding cavity near the mid-span and the secondary shedding cavity at each side of the twisted hydrofoil,and further induces the remarkable pressure gradient around shedding *** with the development of the primary and the secondary shedding cavities,the great pressure gradient associated with large cavity volume variation promotes the vortical flow generation and the spatial deformation of vortex structure during cavitation evolution,and results in the primary and the secondary U-type ***,dynamic mode decomposition(DMD)analysis is utilized to confirm the interaction among the main flow,the main reentrant jet and two side reentrant jets,and *** results indicate that the proposed NMSST PANS model is suitable to simulate the complicated cavitating turbulent flow for various engineering applications.

关键词： Cavitating turbulent flow partially averaged Navier-Stokes(PANS)model hydrofoil numerical simulation

Shear-thinning Catechol-modified Chitosan Hydrogel Loaded with Silver Nanoparticles for Endoscopic Submucosal Dissection

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Chinese Journal of Polymer Science 2024年第8期42卷 1147-1155页

作者： Wen-Jun Feng yan-He Wu Xiao-yang Liu zheng-Ke Wang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310058China

Shear-thinning hydrogels have emerged for endoscopic submucosal dissection,while wound intervention after surgery has rarely been ***,a catechol-modified chitosa n hydrogel with shear-thinning property was developed for simultaneously facilitating endoscopic submucosal dissection and postoperative wound *** from the shear-thinning and self-healing characteristics,the asprepared hydrogel showed easily endoscopic *** also performed very well as submucosal cushion,which could remain above 70%after injection for 120 min in ex vivo porcine large intestine *** fact,the cushion height of normal saline dramatically decreased to 46%of the initial height at 30 *** nanoparticles encapsulated into the network endowed the hydrogel with almost reached 100%antibacterial effect against *** and *** hemolysis ratio of the hydrogel was calculated to be as low as 0.8%.Combined with good hemocompatibility and cytocompatibility,the as-prepared hydrogel displayed much higher in vivo wound closu re and healing efficacy than normal *** results demonstrated the superiority of the shear-thinning chitosan hydrogel in facilitating clinical endoscopic submucosal dissection surgery.

关键词： Shear-thinning hydrogel Endoscopic mucosal dissection Wound healing Catechol-modified chitosan Silver nanoparticles

Advances of machine learning in materials science: Ideas and techniques

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Frontiers of physics 2024年第1期19卷 155-194页

作者： Sue Sin Chong Yi Sheng Ng hui-Qiong Wang Jin-Cheng zheng Department of New Energy Science and Engineering Xiamen University MalaysiaSepang 43900Malaysia Engineering Research Center of Micro-nano Optoelectronic Materials and Devices Ministry of EducationFujian Key Laboratory of Semiconductor Materials and ApplicationsCI Center for OSEDand Department of PhysicsXiamen UniversityXiamen 361005China

In this big data era, the use of large dataset in conjunction with machine learning (ML) has been increasingly popular in both industry and academia. In recent times, the field of materials science is also undergoing a big data revolution, with large database and repositories appearing everywhere. Traditionally, materials science is a trial-and-error field, in both the computational and experimental departments. With the advent of machine learning-based techniques, there has been a paradigm shift: materials can now be screened quickly using ML models and even generated based on materials with similar properties;ML has also quietly infiltrated many sub-disciplinary under materials science. However, ML remains relatively new to the field and is expanding its wing quickly. There are a plethora of readily-available big data architectures and abundance of ML models and software;The call to integrate all these elements in a comprehensive research procedure is becoming an important direction of material science research. In this review, we attempt to provide an introduction and reference of ML to materials scientists, covering as much as possible the commonly used methods and applications, and discussing the future possibilities.

关键词： machine learning materials science

A buffer overflow detection and defense method based on RiSC-V instruction set extension

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Cybersecurity 2024年第2期7卷 28-43页

作者： Chang Liu yan-Jun Wu Jing-zheng Wu Chen Zhao Intelligent Software Research Center Institute of SoftwareChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijingChina

Buffer overflow poses a serious threat to the memory security of modern operating *** overwrites the con-tents of other memory areas by breaking through the buffer capacity limit,destroys the system execution environ-ment,and provides implementation space for various system attacks such as program control flow *** makes it a wide range of harms.A variety of security technologies have been proposed to deal with system security problems including buffer *** example,No eXecute(NX for short)is a memory management technology commonly used in Harvard *** can refuse the execution of code which residing in a specific memory,and can effectively suppress the abnormal impact of buffer overflow on control ***,in recent years,it has also been used in the field of system security,deriving a series of solutions based on NX technology,such as ExecShield,DEP,StackGuard,***,these security solutions often rely too much on the processor archi-tecture so that the protection coverage is insufficient and the accuracy is *** in the emerging system architecture field represented by RiSC-V,there is still a lack of effective solutions for buffer overflow *** the continuous rapid development of the system architecture,it is urgent to develop defense methods that are applicable to different system application environments and oriented to all executable memory spaces to meet the needs of system security ***,we propose BOP,A new system memory security design method based on RISC-V extended instructions,to build a RISC-V buffer overflow detection and defense system and deal with the buffer overflow threat in *** to this method,NX technology can be combined with program control flow analysis,and Nx bit mechanism can be used to manage the executability of memory space,so as to achieve a more granular detection and defense of buffer overflow attacks that may occur in RISC-V system

关键词： RISc-V Operating system security Buffer overflow Control flow hijacking Nx bit Xibop

Impact of Ni particle size on CO_(2)activation and CO formation during reforming process:A density functional theory study

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Frontiers in Energy 2024年第4期18卷 525-534页

作者： Juntian NIU Shengzhuo CHEN Xianrong zheng Haiyu LIU yan JIN Jingyu RAN College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Low-grade Energy Utilization Technologies and Systems(Ministry of Education) Chongqing UniversityChongqing 400044China

In recent years,the dry reforming of methane(DRM)reaction has gained widespread attention due to its effective utilization of two major greenhouse *** Ni-based catalysts for DRM exhibit a strong dependence on particle size,however,the reaction mechanisms involved remain *** this work,the effect of metal particle size on CO_(2)activation and CO formation was explored in the DRM reaction using the density functional ***/MgO(x=13,25,37)was constructed to investigate the CO_(2)activation and the formation of CO during the DRM *** is found that CO_(2)is more inclined to undergo chemisorption on Nix/MgO before *** the variation in particle size,the main activation pathway of CO_(2)on the catalyst *** the smallest Ni13/MgO,CO_(2)tends to directly dissociate,while on the larger Ni25/MgO and Ni37/MgO,the hydrogenation dissociation of CO_(2)is more kinetically *** to Ni13/MgO and Ni37/MgO,the oxidation of surface C atoms and the oxidation of CH occur more readily on Ni25/*** indicates that C atoms are less likely to form on Ni25 particle and are more easily to be *** some extent,the results suggest that Ni25/MgO exhibits superior resistance to carbon formation.

关键词： particle size Ni/MgO catalyst CO_(2)activation CO formation

Dynamic lithium-compensation mechanism for densification of garnet-type Li_(7)La_(3)Zr_(2)O_(12)electrolyte by Li_(2)O atmosphere buffer pair

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Nano Research 2024年第7期17卷 6184-6191页

作者： Chujun zheng Ya Chen Haoxin Dong yan Lu Jun Jin Zhaoyin Wen CAS Key Laboratory of Materials for Energy Conversion Shanghai Institute of CeramicsChinese Academy of ScienceShanghai 200050China State Key Lab High Performance Ceram and Superfine Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Solid-state lithium metal batteries are one of the most promising options for next-generation batteries pursuing high-energy density and ***,the inevitable volatilization of lithium compounds during sintering leads to low relative density and low ionic conductivity of solid-state ***,the dynamic lithium-compensation mechanism is proposed to facilitate the densification of Ta-substituted garnet-type electrolyte(Li_(6.5)La_(3)Zr_(1.5)Ta_(0.5)O_(12)(LLZT))through the reversible manipulating of Li_(2)O ***_(2)ZrO_(3)is used as mother powder additive,which reacts with Li_(2)O in sintering atmosphere and forms Li_(6)Zr_(2)O_(7).Li_(2)ZrO_(3)/Li_(6)Zr_(2)O_(7)buffer pair manipulates the sintering Li_(2)O atmosphere,which is vital for LLZT,within the Li_(2)O partial pressure range corresponding to Li_(2)ZrO_(3)and Li_(6)Zr_(2)O_(7).Furthermore,the reversibility mechanism of buffer pair for Li_(2)O absorption and release is *** obtained LLZT exhibits a relative density of over 96%and an ionic conductivity exceeding 7×10^(−4)S·cm^(−1)with no abnormal grain *** symmetric cell demonstrates an excellent lithium dendrite suppressing ability(stable cycling at a current density of 0.3 mA·cm^(−2)for over 1000 h).Such dynamic lithium-compensation strategy has been successfully applied in atmosphere manipulation of LLZT sintering process,which reduces the dependence of LLZT on the Li_(2)O atmosphere,making it conducive to large-scale preparation of electrolyte ceramics.

关键词： solid-state batteries garnet-type electrolyte high-density electrolyte dynamic lithium-compensation buffer pair

Multi-point impact behavior and the relationship between CAI strength and DBIP of PMI foam sandwich structures

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Chinese Journal of Aeronautics 2024年第10期37卷 265-274页

作者： Keyu ZHU Xitao zheng Jiaming SUN Guoyue WANG Leilei yan School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

Sandwich structures are vulnerable to multi-point impacts,and such impacts can result in a reduction in residual strength even catastrophic ***,the multi-point impact behaviors of PMI foam sandwich structure are investigated and studied using experimental and numerical coupled *** impact energy levels and five Distances Between Impact Positions(DBIP)are considered in details,and representative impact characteristics are compared to reveal the association between Compression After Impact(CAI)strength and *** indicate that the interference between the multi-point impact events has a dominant effect on CAI strength when DBIP is small,and the variation in bending stiffness induced by the boundary effect is the dominant factor affecting CAI strength when DBIP ranges from 20 mm to 60 *** addition,matrix damage represents the primary damage mode in multi-point impact,and the calculated ratio of energy absorbed by the top face sheet and honeycomb core,in relation to the total absorbed energy,serves as a clear indicator of the damage severity experienced by both *** work is enlightening for the structural design of impact-resistant composites.

关键词： Multi-point impact Damage mechanism Interference effect CAI strength Numerical method

Solving the subset sum problem by the quantum Ising model with variational quantum optimization based on conditional values at risk

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 43-55页

作者： Qilin zheng Miaomiao Yu Pingyu Zhu yan Wang Weihong Luo Ping Xu Institute for Quantum Information and State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China Hefei National Laboratory Hefei 230088China

The subset sum problem is a combinatorial optimization problem,and its complexity belongs to the nondeterministic polynomial time complete(NP-Complete)*** problem is widely used in encryption,planning or scheduling,and integer *** accurate search algorithm with polynomial time complexity has not been found,which makes it challenging to be solved on classical *** effectively solve this problem,we translate it into the quantum Ising model and solve it with a variational quantum optimization method based on conditional values at *** proposed model needs only n qubits to encode 2ndimensional search space,which can effectively save the encoding quantum *** model inherits the advantages of variational quantum algorithms and can obtain good performance at shallow circuit depths while being robust to noise,and it is convenient to be deployed in the Noisy Intermediate Scale Quantum *** investigate the effects of the scalability,the variational ansatz type,the variational depth,and noise on the ***,we also discuss the performance of the model under different conditional values at *** computer simulation,the scale can reach more than nine *** selecting the noise type,we construct simulators with different QVs and study the performance of the model with *** addition,we deploy the model on a superconducting quantum computer of the Origin Quantum Technology Company and successfully solve the subset sum *** model provides a new perspective for solving the subset sum problem.

关键词： subset sum problem quantum Ising model conditional values at risk variational quantum optimization

Enhancement of comprehensive properties of Nb-Si based in-situ composites by Ho rare earth doping

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Rare Metals 2024年第9期43卷 4508-4520页

作者： Wei Wei Qi Wang Rui-Run Chen Chao-Wen zheng yan-Qing Su National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

This study examines the microstructure,mechanical properties(with a focus on room-temperature toughness),and oxidation resistance of Ho-doped NbDSi based in-situ *** base alloy consists of the coarse primary Nb_(5)Si_(3)phase and the Nb_(5)Si_(3)+Nbss(Nb solid solution)eutectic *** doping influences the solidification *** the Ho doping is higher than0.2 at%,the alloys transform into eutectic *** can be solid-solved in trace amounts in the Nbss ***,most of Ho forms a stable Ho oxide phase,which alleviates oxygen contamination problem to some ***,the interface separation between Ho oxide and other phases reduces the plastic deformation ***,with 0.4 at%Ho doping,the K_(Q)value is18.03 MPa·m^(1/2),which is 31.1%higher than that of the base *** strength of the Ho-doped alloys does not deteriorate with an increase in ***,the large network-like Ho_(2)O_(3)in the 0.8Ho alloy causes a decrease in toughness and *** addition,the Ho oxide phase effectively blocks the inward oxygen *** 0.8 at%Ho doping,the oxidation mass gain per unit area is 10.16 mg·cm^(2),which is 39.7%lower than that of the base alloy.

关键词： Nb-Si based composites Rare earth elements Ho Microstructure Properties

All-trans retinoic acid alleviates transmissible gastroenteritis virus-induced intestinal inflammation and barrier dysfunction in weaned piglets

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Journal of Animal Science and Biotechnology 2024年第3期15卷 1131-1144页

作者： Junning Pu Daiwen Chen Gang Tian Jun He Ping zheng Zhiqing Huang Xiangbing Mao Jie Yu Yuheng Luo Junqiu Luo hui yan Aimin Wu Bing Yu Institute of Animal Nutrition Sichuan Agricultural UniversityChengdu 611130SichuanPeople’s Republic of China Key Laboratory of Animal Disease-Resistance Nutrition Ministry of EducationMinistry of Agriculture and Rural AffairsKey Laboratory of Sichuan Province611130 ChengduSichuanPeople’s Republic of China

Background Transmissible gastroenteritis virus(TGEV)is one of the main pathogens causing severe diarrhea of *** pathogenesis of TGEV is closely related to intestinal ***-trans retinoic acid(ATRA)is the main active metabolite of vitamin A,which has immunomodulatory and anti-inflammatory ***,it is unclear whether ATRA can alleviate TGEV-induced intestinal inflammation and barrier dysfunction in *** study aimed to investigate the effects of ATRA on growth performance,diarrhea,intestinal inflammation and intesti-nal barrier integrity of TGEV-challenged *** In a 19-d study,32 weaned piglets were randomly divided into 4 treatments:Control group(basal diet),TGEV group(basal diet+TGEV challenge),TGEV+ATRA5 group(basal diet+5 mg/d ATRA+TGEV challenge)and TGEV+ATRA15 group(basal diet+15 mg/d ATRA+TGEV challenge).On d 14,piglets were orally administered TGEV or the sterile *** Feeding piglets with 5 and 15 mg/d ATRA alleviated the growth inhibition and diarrhea induced by TGEV(P<0.05).Feeding piglets with 5 and 15 mg/d ATRA also inhibited the increase of serum diamine oxidase(DAO)activ-ity and the decrease of occludin and claudin-1 protein levels in jejunal mucosa induced by TGEV,and maintained intestinal barrier integrity(P<0.05).Meanwhile,5 mg/d ATRA feeding increased the sucrase activity and the expres-sions of nutrient transporter related genes(GLUT2 and SLC7A1)in jejunal mucosa of TGEV-challenged piglets(P<0.05).Furthermore,5 mg/d ATRA feeding attenuated TGEV-induced intestinal inflammatory response by inhibit-ing the release of interleukin(IL)-1β,IL-8 and tumor necrosis factor-α(TNF-α),and promoting the secretion of IL-10 and secretory immunoglobulin A(sIgA)(P<0.05).Feeding 5 mg/d ATRA also down-regulated the expressions of Toll-like receptors and RIG-I like receptors signaling pathway related genes(TLR3,TLR4,RIG-I,MyD88,TRIF and MAVS)and the phosphorylation level of nuclear factor-κB-p65(NF-κB p65),and

关键词： All-trans retinoic acid Inflammation Intestinal barrier Piglets Transmissible gastroenteritis virus