检索结果-南通市图书馆

Investigation on the dynamic behavior of cloud cavitation around a flexible hydrofoil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2023年第4期35卷 712-723页

作者： yun-qing liu Wei Zhao Zhi Pan Zhi-pu Guo Rui Yuan Qin Wu School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China Wuhan Second Ship Design and Research Institute Wuhan430205China

The objective of this paper is to investigate the dynamic behavior of cloud cavitating flow around a flexible hydrofoil with experimental and numerical *** tightly coupled fluid-structure interaction(FSI)modeling is applied and validated with the experimental *** Q-criterion andω-criterion are applied to illustrate the interaction between the vortex structures and *** flexibility is seen to result in nose-up twist deformation,causing a reduction of the shedding frequency from an increase in the attached cavity *** to the flexibility,the fluctuation of load coefficients of the flexible hydrofoil is larger than that of the rigid ***,the re-entrant jet propagation speed of the flexible hydrofoil is greater than that of the rigid *** shed cloud cavity is observed to be uniform along the flexible hydrofoil span under the combined influence of the strong vibration and the gap flow.

关键词： Cloud cavitation fluid-structure interaction(FSI) vortex structures flexible hydrofoil

Unusual photocarrier and coherent phonon dynamics behaviors of layered PdSe_(2)unveiled by ultrafast spectroscopy of the edge surface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 143-152页

作者： Tiantian yun Changfu Huo Jinluo Cheng Zhi-Bo liu Xiao-qing Yan Key Laboratory of Weak-Light Nonlinear Photonics Ministry of EducationSchool of PhysicsNankai UniversityTianjin 300071China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China GPL Photonics Laboratory Key Laboratory of Luminescence Science and TechnologyChinese Academy of Sciences&State Key Laboratory of Luminescence Science and ApplicationsChangchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Layered materials exhibit different electronic and phonon properties along in-plane and out-of-plane directions;existing studies focus on their in-plane behaviors,and the influence of such anisotropies on the dynamics of photocarriers and phonons is ***,we fabricate layered PdSe_(2)crystals with flat edge surfaces and compare the time-resolved ultrafast spectroscopies on their basal and edge *** differences in the transient reflection spectroscopies reveal the inconsistent photocarrier and phonon dynamics behaviors on the two surfaces:the slow hot carrier relaxation process is accelerated and the thermoelasticity-induced longitudinal coherent acoustic phonon oscillation completely vanishes on the edge surface,as compared with the basal *** analysis reveals that the inconsistent hot carrier dynamics originate from the anisotropic properties of low-energy phonons in PdSe_(2),and the absence of phonon oscillation on the edge surface results from the wavevector-limited sensitivity of acoustic B_(1u)***,polarization-dependent spectroscopies indicate the diverse optical anisotropies beyond the in-plane of PdSe_(2).This work provides a new method to explore unique physical properties and modulate the optical anisotropy of layered materials.

关键词： PdSe_(2) ultrafast spectroscopy edge surface carrier dynamics coherent phonon oscillation anisotropy

维普期刊数据库

High-resolution neutronics model for ^(238)Pu production in high-flux reactors

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第5期35卷 226-236页

作者： qing-Quan Pan qing-Fei Zhao Lian-Jie Wang Bang-Yang Xia yun Cai Jin-Biao Xiong Xiao-Jing liu School of Nuclear Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610200China

We proposed and compared three methods(filter burnup,single energy burnup,and burnup extremum analysis)to build a high-resolution neutronics model for 238Pu production in high-flux *** filter burnup and single energy burnup methods have no theoretical approximation and can achieve a spectrum resolution of up to~1 eV,thereby constructing the importance curve and yield curve of the full energy *** burnup extreme analysis method combines the importance and yield curves to consider the influence of irradiation time on production efficiency,thereby constructing extreme *** three curves,which quantify the transmutation rate of the nuclei in each energy region,are of physical significance because they have similar distributions.A high-resolution neutronics model for ^(238)Pu production was established based on these three curves,and its universality and feasibility were *** neutronics model can guide the neutron spectrum optimization and improve the yield of ^(238)Pu by up to 18.81%.The neutronics model revealed the law of nuclei transmutation in all energy regions with high spectrum resolution,thus providing theoretical support for high-flux reactor design and irradiation production of ^(238)Pu.

关键词： ^(238)Pu Neutronics model High-flux reactor Spectrum resolution Spectrum optimization

维普期刊数据库

Contact engineering for temperature stability improvement of Bi-contacted MoS2 field effect transistors

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第6期67卷 172-179页

作者： Zizheng liu qing ZHANG Xiaohe HUANG Chunsen liu Peng ZHOU State Key Laboratory of Integrated Chip and Systems School of MicroelectronicsZhangjiang Fudan International Innovation CenterFudan University Frontier Institute of Chip and System Shanghai Key Lab for Future Computing Hardware and SystemFudan University Shaoxin Laboratory

Semimetallic bismuth（Bi） is one of the most effective strategies for reducing the contact resistance of two-dimensional transition metal dichalcogenide field effect transistors（FETs）. However, the low melting point of Bi contact（271.5℃） limits its reliable applications. In this study, we demonstrated that the temperature stability of Bi-contacted electrodes could be improved by inserting a high-melting point semimetallic antimony（Sb） between the Bi contacting layer and the gold（Au） capping layer. The proposed Bi/Sb/Au contact electrodes tended to form a metal mixture with a continuous surface during the heating process（Voids appeared on the surface of the Bi/Au contact electrodes after heating at 120℃）. Because of the improved contacting layer formed by the semimetal Bi/Sb alloy, the fabricated Bi/Sb/Au-contacted molybdenum sulfide（MoS2） FETs with different gate lengths demonstrated higher on-state current stability after heating treatment than the Bi/Au contact. Because of the Bi/Sb/Au contact and poly（methyl methacrylate） package, the MoS2FETs demonstrated time stability of at least two months from the almost unchanged transfer characteristics. The electrical stability indicates that the insertion of semimetallic Sb is a promising technology for reliable Bi-based contact.

关键词： temperature stability semimetallic bismuth contact semimetallic antimony contact MoS$_{2}$ FETs time stability

同方期刊数据库

Proposing a machine learning approach to analyze and predict basic high-temperature properties of iron ore fines and its factors

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2024年第5期31卷 1082-1094页

作者： qing-ke Sun Yao-zu Wang Jian-liang Zhang Zheng-jian liu Le-le Niu Chang-dong Shan yun-fei Ma Institute of Artificial Intelligence University of Science and Technology BeijingBeijing100083China School of Intelligence Science and Technology University of Science and Technology BeijingBeijing100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China

The basic high-temperature properties of iron ore play a crucial role in optimizing sintering and ore blending,but the testing process for these properties is complex and has significant lag time,which cannot meet the actual needs of ore blending.A prediction model for the basic high-temperature properties of iron ore fines was thus proposed based on a combination of machine learning algorithms and genetic ***,the prediction accuracy of different machine learning models for the basic high-temperature properties of iron ore fines was ***,a random forest model optimized by genetic algorithms was built,further improving the prediction accuracy of the *** test results show that the random forest model optimized by genetic algorithms has the highest prediction accuracy for the lowest assimilation temperature and liquid phase fluidity of iron ore,with a determination coefficient of 0.903 for the lowest assimilation temperature and 0.927 for the liquid phase fluidity after *** trained model meets the fluctuation requirements of on-site testing and has been successfully applied to actual production on site.

关键词： Iron ore Basic high-temperature property Machine learning Random forest Genetic algorithm

Nuclear volume effects in kinetic isotope fractionation:A case study of mercury oxidation by chlorine species

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2024年第3期43卷 411-423页

作者： Chenlu Yang Yining Zhang yun liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the effect of the NVE on these kinetic processes is not *** total fractionations(MDFs+NVEinduced MIFs)of several representative Hg-incorporated substances were selected and calculated with ab initio calculations in this work for both equilibrium and kinetic ***-induced MIFs were calculated with scaled contact electron densities at the nucleus through systematic evaluations of their accuracy and errors using the Gaussian09 and DIRAC19 packages(named the electron density scaling method).Additionally,the NVE-induced kinetic isotope effect(KIE)of Hg isotopes are also calculated with this method for several representative Hg oxidation reactions by chlorine *** KIEs for 202 Hg/^(198)Hg ranging from−2.27‰to 0.96‰are *** anomalous^(202)Hg-enriched KIEs(δ^(202)Hg/^(198)Hg=0.83‰,0.94‰,and 0.96‰,)caused by the NVE are observed,which are quite different from the classical view(i.e.,light isotopes react faster than the heavy ones).The electron density scaling method we developed in this study can provide an easier way to calculate the NVE-induced KIEs for heavy isotopes and serve to better understand the fractionation mechanisms of mercury isotope systems.

关键词： Nuclear volume effect Kinetic fractionation Hg isotopes Ab initio calculations

维普期刊数据库

MRm-DLDet:a memory-resident malware detection framework based on memory forensics and deep neural network

在线全文

学校读者我要写书评

暂无评论

Cybersecurity 2024年第1期7卷 88-109页

作者： Jiaxi liu yun Feng Xinyu liu Jianjun Zhao Qixu liu Institute of Information Engineering Chinese Academy of SciencesBeijing 100085China School of Cyber Security University of Chinese Academy of SciencesBeijing 100049China

Cyber attackers have constantly updated their attack techniques to evade antivirus software detection in recent *** popular evasion method is to execute malicious code and perform malicious actions only in ***-cious programs that use this attack method are called memory-resident malware,with excellent evasion capability,and have posed huge threats to cyber *** static and dynamic methods are not effective in detect-ing memory-resident *** addition,existing memory forensics detection solutions perform unsatisfactorily in detection rate and depend on massive expert knowledge in memory *** paper proposes MRm-DLDet,a state-of-the-art memory-resident malware detection framework,to overcome these ***-DLDet first builds a virtual machine environment and captures memory dumps,then creatively processes the memory dumps into RGB images using a pre-processing technique that combines deduplication and ultra-high resolution image cropping,followed by our neural network MRmNet in MRm-DLDet to fully extract high-dimensional features from memory dump files and detect *** receives the labeled sub-images of the cropped high-resolution RGB images as input of ResNet-18,which extracts the features of the *** trains a network of gated recurrent units with an attention ***,it determines whether a program is memory-resident malware based on the detection results of each sub-image through a specially designed voting *** created a high-quality dataset consisting of 2,060 benign and memory-resident *** other words,the dataset contains 1,287,500 labeled sub-images cut from the MRm-DLDet transformed ultra-high resolution RGB *** implement MRm-DLDet for Windows 10,and it performs better than the latest methods,with a detection accuracy of up to 98.34%.Moreover,we measured the effects of mimicry and adversarial attacks on MRm-DLDet,and the experimental results demonstrated the robustness

关键词： Memory-resident malware Memory forensics Malware detection Deep learning Ultra-high resolution image

RNA modifications in cellular metabolism:implications for metabolism-targeted therapy and immunotherapy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Signal Transduction and Targeted Therapy 2024年第4期9卷 1565-1594页

作者： Wei-Wei liu Si-qing Zheng Tian Li yun-Fei Fei Chen Wang Shuang Zhang Fei Wang Guan-Min Jiang Hao Wang Department of Laboratory Medicine The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiChina School of Clinical Medicine Shandong UniversityJinanChina Core Unit of National Clinical Research Center for Laboratory Medicine HefeiChina Neurosurgical Department The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiChina Department of Clinical Laboratory The Fifth Affiliated HospitalSun Yat-sen UniversityZhuhaiChina

Cellular metabolism is an intricate network satisfying bioenergetic and biosynthesis requirements of *** studies have been constantly making inroads in our understanding of pathophysiology,and inspiring development of *** a crucial component of epigenetics at post-transcription level,RNA modification significantly determines RNA fates,further affecting various biological processes and cellular *** be noted,immunometabolism defines the metabolic alterations occur on immune cells in different stages and immunological *** this review,we characterize the distribution features,modifying mechanisms and biological functions of 8 RNA modifications,including N6-methyladenosine(m6A),N6,2'-O-dimethyladenosine(m6Am),N1-methyladenosine(m1A),5-methylcytosine(m5C),N4-acetylcytosine(ac4C),N7-methylguanosine(m7G),Pseudouridine(V),adenosine-to-inosine(A-to-l)editing,which are relatively the most studied *** regulatory roles of these RNA modification on metabolism in diverse health and disease contexts are comprehensively described,categorized as glucose,lipid,amino acid,and mitochondrial *** we highlight the regulation of RNA modifications on immunometabolism,further influencing immune *** all,we provide a thorough discussion about clinical implications of RNA modification in metabolism-targeted therapy and immunotherapy,progression of RNA modification-targeted agents,and its potential in RNAtargeted ***,we give legitimate perspectives for future researches in this field from methodological requirements,mechanistic insights,to therapeutic applications.

关键词： metabolism targeted alterations

The synthetic gauge field and exotic vortex phase with spin-orbital-angular-momentum coupling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第8期76卷 54-61页

作者： Yingqi liu yun Chen Yuangang Deng Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing & School of Physics and Astronomy Sun Yat-Sen University (Zhuhai Campus)

Ultracold atoms endowed with tunable spin-orbital-angular-momentum coupling(SOAMC)represent a promising avenue for delving into exotic quantum phenomena. Building on recent experimental advancements, we propose the generation of synthetic gauge fields, and by including exotic vortex phases within spinor Bose–Einstein condensates, employing a combination of a running wave and Laguerre–Gaussian laser fields. We investigate the ground-state characteristics of the SOAMC condensate, revealing the emergence of exotic vortex states with controllable orbital angular momenta. It is shown that the interplay of the SOAMC and conventional spin-linear-momentum coupling induced by the running wave beam leads to the formation of a vortex state exhibiting a phase stripe hosting single multiply quantized singularity. The phase of the ground state will undergo the phase transition corresponding to the breaking of rotational symmetry while preserving the mirror symmetry. Importantly, the observed density distribution of the ground-state wavefunction, exhibiting broken rotational symmetry, can be well characterized by the synthetic magnetic field generated through light interaction with the dressed spin state. Our findings pave the way for further exploration into the rotational properties of stable exotic vortices with higher orbital angular momenta against splitting in the presence of synthetic gauge fields in ultracold quantum gases.

关键词： spin-orbital-angular-momentum coupling synthetic gauge fields ultracold atoms vortex phases