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High-temperature mechanical properties of near-eutectoid steel

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International Journal of Minerals,Metallurgy and Materials 2013年第9期20卷 829-834页

作者： Jun fu fu-ming Wang Fang Hao Gui-xiang Jin State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The high-temperature mechanical properties of near-eutectoid steel were studied with a Cleeble-1500 simu- lation machine. Zero strength temperature （ZST）, zero ductility temperature （ZDT）, hot ductility curves, and strength curves were measured. Two brittle zones and one plastic zone were found in the temperature range from the melting point to 600℃. Embrittlement in zone I is caused by the existence of liquid film along dendritic interfaces. Ductility loss in zone Ⅲ mainly results from precipitates and inclusions as well as S segregation along grain boundaries. Pearlite transformation also accounts for ductility deterioration in the temperature range of 700-600℃. Moreover, the straightening temperature of the test steel should be higher than 925℃ for avoiding the initiation and propagation of surface cracks in billets.

关键词： carbon steel eutectic alloys high temperature properties mechanical properties brittleness straightening billets

Thermal shock behavior of ZrB2-SiC ceramics with different quenching media

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Frontiers of Materials Science 2013年第2期7卷 184-189页

作者： Chang-An WANG ming-fu WANG State Key Lab of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Science and Technology on Scramjet Laboratory Beijing 100074 China

The thermal shock behavior of ZrB2-SiC ceramics was studied with water, air and methyl silicone oil as quenching media, respectively. The temperature of all coolants was room temperature （25℃） and the residual strength of the ceramics after quenching was tested. The strength of the ceramics after water quenching had an obvious drop when the temperature difference, AT, was about 275℃, while the residual strength of the specimens quenched by air and silicone oil only varied a little and even increased slightly when the temperature difference was higher than 800℃. The different thermal conductive coefficient of the coolants and surface heat transfer coefficient resulted in the differences in the thermal shock behavior. The formation of oxidation layer was beneficial for improving the residual strength of the ceramics after quenching.

关键词： ultra-high temperature ceramic (UHTC) zirconium diboride (ZrB2) siliconcarbide (SIC) thermal shock resistance mechanical property

Integrated HI emission in galaxy groups and clusters

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Research in Astronomy and Astrophysics 2017年第10期17卷 15-26页

作者： Mei Ai ming Zhu Jian fu National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences

The integrated HI emission from hierarchical structures such as groups and clusters of galax- ies can be detected by FAST at intermediate redshifts. Here we propose to use FAST to study the evolution of the global HI content of clusters and groups over cosmic time by measuring their integrated HI emissions. We use the Virgo Cluster as an example to estimate the detection limit of FAST, and have estimated the integration time to detect a Virgo type cluster at different redshifts （from z = 0.1 to z ---- 1.5）. We have also employed a semi-analytic model （SAM） to simulate the evolution of HI contents in galaxy clusters. Our simulations suggest that the HI mass of a Virgo-like cluster could be 2-3 times higher and the physical size could be more than 50% smaller when redshift increases from z = 0.3 to z = 1. Thus the integration time could be reduced significantly and gas rich clusters at intermediate redshifts can be detected by FAST in less than 2 hours of integration time. For the local Universe, we have also used SAM simulations to create mock catalogs of clusters to predict the outcomes from FAST all sky surveys. Comparing with the optically selected catalogs derived by cross matching the galaxy catalogs from the SDSS survey and the ALFALFA survey, we find that the HI mass distribution of the mock catalog with 20 s of integration time agrees well with that of observations. However, the mock catalog with 120 s of integration time predicts many more groups and clusters that contain a population of low mass HI galaxies not detected by the ALFALFA survey. A future deep HI blind sky survey with FAST would be able to test such prediction and set constraints on the numerical simulation models. The observational strategy and sample selections for future FAST observations of galaxy clusters at high redshifts are also discussed.

关键词： galaxy clusters -- neutral hydrogen (HI) -- galaxy evolution

Experimental and Theoretical Study on the Self-Weight Penetration Velocity of Suction Anchor Foundations in Sand

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China Ocean Engineering 2023年第5期37卷 863-875页

作者： SUN Kai MA Hui-huan WANG fu-ming School of Civil Engineering Sun Yat-Sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Guangdong Key Laboratory of Oceanic Civil Engineering Guangzhou 510275China

The application of the wellhead suction anchor in the second production test of natural gas hydrates(NGHs)in the South China Sea(SCS)was met with *** design incorporates a central conductor guide pipe,which distinguishes it from traditional suction ***,this addition resulted in a relatively high penetration resistance and a shallower penetration depth at the self-weight penetration *** mitigate this issue,the current study proposes an optimized design where the end of the suction foundation is *** installation characteristics of the traditional suction foundation and new suction foundation during self-weight penetration into sand are studied through laboratory tests and theoretical *** flat and sharpened bottom shapes are considered in the traditional and new suction *** effects of the initial penetration velocity on the initial penetration depth and soil plug and impact cavity characteristics are systematically *** results show that the self-weight penetration depth of the foundation with a sharpened bottom is 44.5%deeper than that of the foundation with a flat *** are cavities around the foundation at the self-weight penetration stage,and the penetration depth is overestimated by 15%-30%.Finally,a model for predicting the penetration depth of the new suction foundation is proposed.

关键词： suction foundation self-weight penetration penetration velocity soil plug sharpened bottom

Size effects on process performance and product quality in progressive microforming of shafted gears revealed by experiment and numerical modeling

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Advances in Manufacturing 2023年第1期11卷 1-20页

作者： Jun-Yuan Zheng Hui Liu ming-Wang fu Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongPeople’s Republic of China Research Institute for Advanced Manufacturing The Hong Kong Polytechnic UniversityHung HomKowloonHong KongPeople’s Republic of China

As one of the indispensable actuating components in micro-systems,the shafted microgear is in great production *** is a manufacturing process to produce microgears to meet the *** to the small geometrical size,there are uncertain process performance and product quality issues in this production *** this study,the shafted microgears were fabricated in two different scaling factors with four grain sizes using a progressively extrusion-blanking *** explore the unknown of the process,grain-based modeling was proposed and employed to simulate the entire forming *** results show that when the grains are large,the anisotropy of single grains has an obvious size effect on the forming behavior and process performance;and the produced geometries and surface quality are worsened;and the deformation load is *** deformation zones were identified in the microstructures with different hardness and distributions of stress and *** simulation by using the proposed model successfully predicted the formation of zones and revealed the inhomogeneous deformation in the forming *** undesirable geometries of microgears including material unfilling,burr and inclination were observed on the shaft and teeth of gear,and the inclination size is increased obviously with grain *** avoid the formation of inclination and material unfilling,the punch was redesigned,and a die insert was added to constraint the bottom surface of the gear *** new products had then the better forming quality.

关键词： Microforming Microprocess performance Microforming quality Size effect affected deformation behavior Die design optimization

Photoinduced Dehalocyclization to Access Oxindoles Using Formate as a Reductant

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Chinese Journal of Chemistry 2024年第11期42卷 1203-1208页

作者： Wei Ge Jia-Xin Wang ming-Chen fu Yao fu Hefei National Research Center for Physical Sciences at the Microscale iChEMCAS Key Laboratory of Urban Pollutant ConversionAnhui Province Key Laboratory of Biomass Clean EnergyUniversity of Science and Technology of ChinaHefeiAnhui230026 China Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering Hefei University of TechnologyHefeiAnhui230009 China

Herein,we report an efficient and practical protocol for the photoinduced dehalocyclization of ortho-halophenylacrylamides with formate by the engagement of a CO_(2) radical anion to access substituted *** method proceeds smoothly under mild conditions and exhibits a wide range of substrate as well as remarkable functional group compatibility.

关键词： Formate CO_(2)Radical ions Oxindole Photocatalysts Cyclization Organohalides

Limit theorems for supremum of Gaussian processes over a random interval

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Applied Mathematics(A Journal of Chinese Universities) 2018年第3期33卷 335-343页

作者： LIN fu-ming PENG Zuo-xiang School of Statistics and Management Shanghai University of Finance and Economics School of Mathematics and Statistics Sichuan University of Science & Engineering School of Mathematics and Statistics Southwestern University

Let {X(t), t ≥ 0} be a centered stationary Gaussian process with correlation r(t)such that 1-r(t) is asymptotic to a regularly varying function. With T being a nonnegative random variable and independent of X(t), the... 详细信息

关键词： stationary Gaussian process supremum of a process regularly varying functions random intervals

A temporal programming model with atomic blocks based on projection temporal logic

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Frontiers of Computer Science 2014年第6期8卷 958-976页

作者： Xiaoxiao YANG Yu ZHANG ming fu Xinyu FENG State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China Suzhou Institute for Advanced Study University of Science & Technology of China SuZhou 215123 China

Atomic blocks, a high-level language construct that allows programmers to explicitly specify the atomicity of operations without worrying about the implementations, are a promising approach that simplifies concurrent programming. On the other hand, temporal logic is a successful model in logic programming and concurrency verification, but none of existing temporal programming models supports concurrent programming with atomic blocks yet. In this paper, we propose a temporal programming model （αPTL） which extends the projection temporal logic （PTL） to support concurrent programming with atomic blocks. The novel construct that formulates atomic execution of code blocks, which we call atomic interval formulas, is always interpreted over two consecutive states, with the internal states of the block being abstracted away. We show that the framing mechanism in projection temporal logic also works in the new model, which consequently supports our development of an executive language. The language supports concurrency by introducing a loose interleaving semantics which tracks only the mutual exclusion between atomic blocks. We demonstrate the usage of αPTL by modeling and verifying both the fine-grained and coarse-grained concurrency.

关键词： atomic blocks semantics temporal logic programming verification framing

A Lightweight Dynamic Enforcement of Privacy Protection for Android

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Journal of Computer Science & Technology 2019年第4期34卷 901-923页

作者： Zi-Peng Zhang ming fu Xin-Yu Feng School of Computer Science and Technology University of Science and Technology of ChinaHefei 230026China OS Kernel Laboratory Huawei Technologies Co.Ltd.Shanghai 200135China State Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210023China

Inter-process communication(IPC)provides a message passing mechanism for information exchange between *** has been long believed that IPCs can be abused by malware writers to launch collusive information leak using two or more *** work on privacy protection focuses on the simple information leak caused by the individual applications and lacks effective approaches to preventing the collusive information leak caused by IPCs between multiple *** this paper,we propose a hybrid approach to prevent the collusive information leak based on information flow *** approach combines static information flow analysis and dynamic runtime checking *** leak caused by individual processes is prevented through static information flow control,and dynamic checking is done at runtime to prevent the collusive information *** a combination may effectively reduce the runtime overhead of pure dynamic checking,and reduce false-alarms in pure static *** develop this approach based on an abstract and simplified programming model,and formalize a novel definition of the leak-freedom property as our target security property.A simulation-based proof technique is used to prove that our approach is able to guarantee *** proofs are mechanized in Coq.

关键词： privacy protection dynamic runtime checking static information flow control Android verification