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Research.in Astronomy and Astrophysics 2023年第8期23卷 103-116页

作者： Shu Niu Fu-Guo Xie Wei sun Li ji Key Laboratory for Research.in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China University of chinese Academy of Sciences Beijing 100049China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China Key Laboratory of Dark Matter and Space Astronomy Chinese Academy of SciencesNanjing 210023China

The feeding and feedback processes at the vicinity of a supermassive black hole(BH)are essential for our understanding of the connection between supermassive BH and its host *** this work,we provide a detailed investigation,both observational and theoretical,on the diffuse(~2"-20",~0.08-0.8 pc)X-ray emission around Sgr A*.Over two-decade chandra observations are gathered to obtain highest signal-to-noise to *** find that,the line center of iron lines of the outer 8"-18"region,ε_(c)=6.65+0.02-0.03 keV,is comparable to that(ε_(c)=6.60+0.05-0.03 keV)of the inner 2"-5"*** is somewhat unexpected,since the gas temperature decreases further away from the central *** on a dynamical inflow-outflow model that considers the gas feeding by stellar winds from Wolf-Rayet stars,we calculate the X-ray spectrum based on both the conventional collisional ionization equilibrium(CiE)assumption,and the newly developed non-equilibrium ionization(NEi)*** find that,theoretically gases within~8"-10"remain in a CiE state,outside of this radius they will be in the NEi state.A comparison of the properties of~6.6 keV iron lines between CiE and NEi is ***,the NEi interpretation of outer region is supported by the chandra line center ε_(c) measurements of this region.

关键词： X-rays diffuse background-galaxies active-Galaxy center-(galaxies:)quasars emission lines

Strategic Priority Program on Space Science

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空间科学学报 2014年第5期34卷 505-515页

作者： WU ji sun Lilin Certer for Spaoe Science and Appkied Research Chinese Academy of Sciences

in 1957, the launch of the first artificial satellite ushered in a new era for modern space science. The past 50 years' developments in china's space science have witnessed many major missions, and substantial progress has been achieved in space science study, exploration technology as well as experiment technology. Strategic Priority Program on Space Science was officially started in 2011. Through both self-developed space science missions and those with international cooperation,it is expected that the innovative breakthroughs will be realized, leapfrog development of related high-tech will be achieved to establish the important strategic status of space science in national development. To sum up, the implementation of the Strategic Priority Program on Space Science will definitely promote the rapid development of china's space science endeavor, making contributions to china's development and the progress of human civilization.

关键词： Strategic Priority Program on Space Science Science objectives Payload Status

Secure Computation Efficiency Resource Allocation for Massive MiMO-Enabled Mobile Edge Computing Networks

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china Communications 2024年第11期21卷 150-162页

作者： sun Gangcan sun jiwei Hao Wanming Zhu Zhengyu ji Xiang Zhou Yiqing School of Electrical and information Engineering Zhengzhou UniversityZhengzhou 450001China Beijing Key Laboratory of Mobile Computing and Pervasive Device and the institute of Computing Technology Chinese Academy of SciencesBeijing 100190China

in this article,the secure computation efficiency(SCE)problem is studied in a massive multipleinput multiple-output(mMiMO)-assisted mobile edge computing(MEC)*** first derive the secure transmission rate based on the mMiMO under imperfect channel state *** on this,the SCE maximization problem is formulated by jointly optimizing the local computation frequency,the offloading time,the downloading time,the users and the base station transmit *** to its difficulty to directly solve the formulated problem,we first transform the fractional objective function into the subtractive form one via the dinkelbach ***,the original problem is transformed into a convex one by applying the successive convex approximation tech.ique,and an iteration algorithm is proposed to obtain the ***,the stimulations are conducted to show that the performance of the proposed schemes is superior to that of the other schemes.

关键词： eavesdropping massive multiple input multiple output mobile edge computing partial offloading secure computation efficiency

Fermi Blazars in the Zwicky Transient Facility Survey:Properties of Large Optical Variations

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Research.in Astronomy and Astrophysics 2024年第10期24卷 104-115页

作者： Si-Si sun Zhong-Xiang Wang Shun-Hao ji Department of Astronomy School of Physics and AstronomyYunnan UniversityKunming 650091China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

We analyze the optical light curve data,obtained with the Zwicky Transient Facility(ZTF)survey,for 47 γ-ray blazars monitored by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope(Fermi).These 47sources are selected because they are among the Fermi blazars with the largest optical variations in the ZTF *** color-magnitude variation patterns are seen in them,with one being redder-to-stable-when-brighter(RSWB;in 31 sources)and the other being stable when brighter(in 16 sources).The patterns fit with the results recently reported in several similar studies with different ***,we find that the colors in the stable state of the sources share similar values,for which(after being corrected for the Galactic extinction)most sources are in a range of 0.4–*** feature could be intrinsic and may be applied in,for example,study of the intragalactic *** also determine the turning points for the sources showing the RSWB pattern,after which the color changes saturate and become *** find a correlation between optical fluxes and γ-ray fluxes at the turning *** physical implications of the correlation remain to be investigated,probably better with a sample of high-qualityγ-ray flux measurements.

关键词： (galaxies:)BL Lacertae objects:general (galaxies:)quasars:general gamma-rays:galaxies

Experimental and Modeling Study of the Regular Polygon Angle-spiral Liner in Ball Mills

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chinese Journal of Mechanical Engineering 2017年第2期30卷 363-372页

作者： Yi sun Man LiANG Xiaohang jiN Pengpeng ji jihong SHAN College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310014China

Load behavior is one of the most critical factors affecting mills＇ energy consumption and grinding efficiency, and is greatly affected by the liner profiles. Generally, as liner profiles vary, the ball mill performances are extremely different. in order to study the performance of the ball mill with regular polygon angle-spiral liners（RPASLs）, experimental and numerical studies on three types of RPASLs, including regular quadrilateral, pentagonal and hexagonal, are carried out. For the fine product of desired size, two critical parameters are analyzed： the energy input to the mill per unit mass of the fine product, E＊, and the rate of production of the fine product, F＊. Results show that the optimal structure of RPASLs is Quadrilateral ASL with an assembled angle of 50°. Under this condition, the specific energy consumption E＊ has the minimum value of 303 J per fine product and the production rate F＊ has the maximum value of 0.323. The production rate F＊ in the experimental result is consistent with the specific collision energy intensity to total collision energy intensity ratio Es/Et in the simulation. The relations between the production rate F＊ and the specific energy consumption E＊ with collision energy intensity Es and Et are obtained. The simulation result reveals the essential reason for the experimental phenomenon and correlates the mill performance parameter to the collision energy between balls, which could guide the practical application for Quadrilateral ASL.

关键词： Load behavior Regular polygon angle-spiral liner (RPASL) Particle size distribution. Rate of production of fine product Energy consumption. Collision energy intensity

Novel Ship Propulsion System

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chinese Journal of Mechanical Engineering 2009年第2期22卷 198-206页

作者： ji Yulong sun Yuqing ZHANG Hongpeng ZHANG Yindong chEN Haiquan School of Marine Engineering Dalian Maritime University Dalian 116026 China

As the development tends towards high-speed, large-scale and high-power, power of the ship main engine becomes larger and larger. This make the engine design and cabin arrangement become more and more difficult. Ship maneuverability becomes bad. A new ship propulsion system, integrated hydraulic propulsion （iHP）, is put forward to meet the development of modem ship. Principle of iHP system is discussed. Working condition matching characteristic of iHP ship is studied based on its matching characteristic charts. According to their propulsion principle, dynamic mathematic models of iHP ship and direct propulsion （DP） ship are developed. These two models are verified by test sailing and test stand data. Based on the software Matlab/Simulink, comparison research between iHP ship and DP ship is conducted. The results show that cabin arrangement of iHP ship is very flexible, working condition matching characteristic of iHP ship is good, the ratio of power to weight of iHP ship is larger than DP ship, and maneuverability is excellent. iHP system is suitable for engineering ship, superpower ship and warship, etc.

关键词： ship integrated hydraulic propulsion (iHP) ship propulsion system modeling and simulation working condition matching characteristic

An efficient scheme for accelerating the calculation of stacking fault energy in multi-principal element alloys

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Journal of Materials Science & Technology 2024年第8期175卷 204-211页

作者： Haoran sun Zhigang Ding Hao sun Junjun Zhou ji-chang Ren Qingmiao Hu Wei Liu School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

We present the High-Throughput Computing and Statistical Analysis(HCSA)scheme,which efficiently and accurately predicts the stacking fault energies(SFEs)of multi-principal element alloys(MPEAs).Our approach estimates the SFE of a single complex supercell by averaging numerous SFEs from small supercells,resulting in superior accuracy compared to traditional density functional theory(DFT)*** validate our scheme,we applied it to NiFe and Ni_(10)Co_(60)Cr_(25)W_(5)alloys,achieving an SFE error of only 11%,in contrast to the 45%error obtained from traditional DFT calculations for *** observed a strong correlation between the average SFEs of samples with the same valence electron concentration as that of the experimental *** scheme provides an efficient and reliable tool for predicting SFEs in MPEAs and holds the potential to significantly accelerate materials design and discovery processes.

关键词： Multi-principal element alloys Stacking fault energy Density functional theory High-throughput calculation

Transient liquid-phase bonding of superalloy K465 using a Ni-Cr-Fe-B-Si amorphous interlayer alloy

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Rare Metals 2020年第4期39卷 408-412页

作者： ji-De Liu Bo Li Yuan sun Tao jin Xiao-Feng sun Zhuang-Qi Hu Department of Superalloys Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China

A kind of Ni-Cr-Fe-B-Si system amorphous alloy was used as interlayer in transient liquid-phase bonding(TLP bonding)of polycrystalline superalloy *** bonding behavior,microstructure feature and the tensile properties of the joints were *** are B-rich phase and Si-rich phase formed in the center of the seam after bonding at 1210℃for 30 *** isothermal solidification is complete after bonding at 1210℃for 4 *** relationship of the average width of the remnant eutectic zone and bonding time at 1210℃is *** tensile strength of the bonded joint at room temperature and 900℃is comparable to that of K465 alloy.

关键词： interlayer alloy Transient liquid-phase bonding Superalloy K465 Alloy

improved shielding and filtering applied to immunity enhancement of underground gas sensors

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Journal of china University of Mining and Technology 2008年第2期18卷 220-223页

作者： sun ji-ping MA Feng-ying State Key Laboratory of Coal Resources and Safe Mining China University of Mining ＆ Technology Beijing 100083 China College of Electronic information and Control Engineering Shandong Institute of Light Industry Jinan Shandong 250100 China

in order to eliminate false alarms,issued by gas sensors in coal mining,caused by Electromagnetic interference(EMi),both computer simulation and field measurements were introduced to analyze the underground EMi distribution.A simplified model of a sensor with metal enclosure was established and the effects of shielding properties about the enclosure aperture were *** the haulage motor is the moving EMi source,varying with time,the onsite flameproof measuring instruments cannot accomplish synchronous measurements of electromagnetic field *** simplify the field measurements,two sensors,one with a lead and the other without a lead,were chosen to conduct the contrasting *** EMi current caused by the perforation lead was comparatively strong and therefore nickel zinc ferrite beads were used to cut off the EMi propagation *** peak value of the interference current was reduced by 20%-70% with the *** switching on the sensor power,the sen-sors still occasionally gave false alarms when the switch of nearby large-scale electric equipment was operated.A complex EMi filter was used and the EMi attenuated *** running results demonstrated that false alarms had been *** con-clude that the improved shielding and filtering are highly significant in enhancing the immunity of the gas sensor.

关键词： false alarms EMi shielding properties filtering immunity

Learning Hierarchical User interest Models from Web Pages

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Wuhan University Journal of Natural Sciences 2006年第1期11卷 6-10页

作者： YANG Feng-qin sun Tie-li sun ji-gui College of Computer Science and Technology Jilin University Changchun 130012 Jilin China Key Laboratory for Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun 120012 Jilin China Department of Computer Science Northeast Normal University Changchun 130024 Jilin China

We propose an algorithm for learning hierarchical user interest models according to the Web pages users have browsed. in this algorithm, the interests of a user are represented into a tree which.is called a user interest tree, the content and the structure of which can change simultaneously to adapt to the changes in a user＇s interests. This expression represents a user＇s specific and general interests as a continuurn. in some sense, specific interests correspond to shortterm interests, while general interests correspond to longterm interests. So this representation more really reflects the users＇ interests. The algorithm can automatically model a us er＇s multiple interest domains, dynamically generate the in terest models and prune a user interest tree when the number of the nodes in it exceeds given value. Finally, we show the experiment results in a chinese Web Site.

关键词： personalization user interest model vector space model agglomerate clustering method