检索结果-南通市图书馆

China Foundry 2012年第2期9卷 114-118页

作者： Liu Zhe Chen weiping Deng Yu state Engineering Research Center for Metallic Materials Net-shape Processing School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou 510640China

Cooling rate and inoculation practice can greatly affect the graphite morphology of ductile irons. In the present research, the effects of the cooling rate and antimony addition on the graphite morphology and mechanical properties of ductile irons have been studied. Three ductile iron castings were prepared through solidification under cooling conditions S （slow）, M （medium） and F （fast）. The cooling rates around the equilibrium eutectic temperature （1,150 ℃） for these cooling conditions （S, M and F） were set at 0.21 ℃.min1, 0.32℃.min1 and 0.37℃-min-1, respectively. In addition, four ductile iron castings were prepared by adding 0.01%, 0.02%, 0.03% and 0.04% （by weight） antimony, respectively under the slow cooling condition. The results show that the nodularity index, tensile strength and hardness of the ductile iron castings without antimony addition are all improved with the increase of cooling rate, while the ductile iron casting solidified under the medium cooling rate possesses the largest number of graphite nodules. Furthermore, for the four antimony containing castings, the graphite morphology and tensile strength are also improved by the antimony additions, and the effect of antimony addition is intensified when the addition increases from 0.01% to 0.03%. Moreover, the rare earth elements （REE）/antimony ratio of 2 appears to be the most effective for fine nodular graphite formation in ductile iron.

关键词： ductile iron cooling rate antimony graphite morphology mechanical properties

Stability analysis on Tingzikou gravity dam along deep-seated weak planes during earthquake

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2012年第1期6卷 69-75页

作者： weiping HE Yunlong HE state Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China

The stability of a gravity dam against sliding along deep-seated weak planes is a universal and important problem encountered in the construction of *** is no recommended method for stability analysis of the dam on deep-seated weak planes under earthquake condition in Chinese design *** Tingzikou dam as an example,the research in this paper is focused on searching a proper way to evaluate the seismic safety of the dam against sliding along deep-seated weak planes and the probable failure modes of dam on deep-seated weak planes during *** is concluded that there are two probable failure modes of the dam along the main weak geological planes in the *** the first mode,the concrete tooth under the dam will be cut and then the dam together with part foundation will slide along the muddy layer;in the second mode,the dam together with part foundation will glide along the path consist of the weak rock layer under the tooth and the muddy layer downstream the *** there is no geological structure planes to form the second slip surface,the intersection of the main and the second slip surface is 40 to 80 m downstream from dam toe,and the angle between the second slip surface and the horizontal plane probably be 25 to 45 degrees.

关键词： gravity dam deep-seated weak planes stability against sliding earthquake

3D Printing of NiCoP/Ti3C2 MXene Architectures for Energy Storage Devices with High Areal and Volumetric Energy Density

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2020年第10期12卷 300-312页

作者： Lianghao Yu weiping Li Chaohui Wei Qifeng Yang Yuanlong Shao Jingyu Sun College of Energy Soochow Institute for Energy and Materials InnovationS(SIEMIS)Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow University215006 SuzhouJiangsuPeople’s Republic of China

Designing high-performance electrodes via 3D printing for advanced energy storage is appealing but remains *** normal cases,light-weight carbonaceous materials harnessing excellent electrical conductivity have served as electrode ***,they struggle with undermined areal and volumetric energy density of supercapacitor devices,thereby greatly impeding the practical ***,we demonstrate the in situ coupling of NiCoP bimetallic phosphide and Ti3C2 MXene to build up heavy NCPM electrodes affording tunable mass loading throughout 3D printing *** resolution of prints reaches 50μm and the thickness of device electrodes is ca.4 ***-printed electrode possessing robust open framework synergizes favorable capacitance of NiCoP and excellent conductivity of MXene,readily achieving a high areal and volumetric capacitance of 20 F cm^-2 and 137 F cm^-3 even at a high mass loading of^46.3 mg cm^-***,an asymmetric supercapacitor full cell assembled with 3D-printed NCPM as a positive electrode and 3D-printed activated carbon as a negative electrode harvests remarkable areal and volumetric energy density of 0.89 mWh cm^-2 and 2.2 mWh cm^-3,outperforming the most of state-of-the-art carbon-based *** present work is anticipated to offer a viable solution toward the customized construction of multifunctional architectures via 3D printing for high-energy-density energy storage systems.

关键词： 3D printing NiCoP/MXene Asymmetric supercapacitor Energy density Tailorable loading

Energy studies of precipitation sequence in Ni_(75)Al_(10)Cr_(15) alloy based on the phase field theory

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2011年第5期54卷 821-826页

作者： DONG weiping CHEN Zheng WANG YongXin state Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China

Based on the phase field theory, the phase precipitation sequence of Ni75A110Cr15 alloy and the free energy of each phase were studied. Moreover, the interatomic potentials of Llo phase, L12 phase and DO22 phase changing with temperature and concen- trations were computed through utilizing the interatomic potentials equations induced by Khachaturyan＇s relational equations between the interatomic potentials and the long-range order （LRO） parameters. Results match preceding work and demonstrate that the phase precipitation sequence of Ni75AlloCr15 alloy is the disordered phase -L10 pre-precipitation phase -L12 equilibrium phase -L12＋DO22 equilibrium phase. Free energies of Llo pre-precipitation phase are higher and interatomic potentials are smaller than those of L12 equilibrium phase; therefore, it is concluded that Llo phase is unstable, and phase transformation would occur to L12 which is more stable; L12 phase precipitates earlier than DO22 phase because L12＇s interaction potentials are larger than DO22＇s.

关键词： precipitation sequence pre-precipitation phase equilibrium phase interatomic potentials free energy phase field theory

Investigation on Normal Dynamic Contact Characteristics of Mechanical Interface of Machine Tools

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2021年第1期34卷 104-123页

作者： Zhiqiang Gao weiping Fu Wen Wang Shuangqi Wang Dongya Zhang Zhifei Xue School of Mechanical and Precision Instrument Engineering Xian University of TechnologyXi’an710048China state Key Laboratory of Power System of Tractor China YITUO Group Co.LtdLuoyang471039China

The dynamic contact characteristics of mechanical interface significantly impact the performance of machine *** static contact behaviors of mechanical interface have been ***,most mechanical interfaces are exposed to dynamic *** is necessary to study the dynamic contact characteristics of mechanical interface.A normal dynamic microcosmic contact model is built using the statistical method,and the interactional effects of adjacent asperities are *** influences of the normal preload,vibrational frequency and displacement amplitude on normal contact stiffness and damping of mechanical interface are *** predicted contact stiffness and damping of mechanical interface are verified by a series of simulations and experiments.

关键词： Dynamic Stiffness Damping Asperity interaction Experiment

The Origin,Historical Variations,and Distribution of Heavy Metals in the Qiongzhou Strait and Nearby Marine Areas

维普期刊数据库评论

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 Ocean university of China 2017年第2期16卷 262-268页

作者： ZHANG Zhiqiang CHEN Liang WANG weiping LI Tuanjie ZU Tingting Guangzhou Institute of Geochemistry Chinese Academy of Sciences:CAS Key Laboratory of Marginal Sea GeologyGuangzhou 510640P.R.China South China Sea Branch of state Oceanic Administration Guangzhou 510300P.R.China South China Sea Branch Institute of Oceanology Chinese Academy of SciencesGuangzhou 510301P.R.China

We analyzed heavy metal concentrations in a number of surface sediments and cores from the Qiongzhou Strait and surrounding marine *** areas of high concentrations are primarily outside the eastern mouth of the Qiongzhou Strait and on the west side of the Leizhou Peninsula,whereas the areas of low concentrations are located primarily in the eastern Qiongzhou *** maximum Cd,Pb and Zn concentrations in the samples collected in our study do not exceed the official standards for marine sediments,whereas the concentrations of Cr and Cu slightly exceed the *** exist between the concentrations of Cu,Pb,Zn,Cr and Cd,and the concentrations of these metals are positively correlated with the mean particle size(φ value),indicating that the finer sediments have adsorbed greater amounts of heavy metal elements than the coarser *** evaluation of the potential environmental risks demonstrates that certain indices of heavy metal pollution and environmental risks are relatively low and may be assigned low risk levels,thereby indicating that,in terms of heavy metals,the marine sedimentary environment in this region is only mildly *** analysis of the contaminant origins shows that the heavy metals in this region primarily originate in the Pearl River Estuary and that a small amount of them is derived from local *** elevated heavy metal concentrations from the upper sections of the cores started 130 years ago,which indicats that heavy metals in the surface sediments are primarily due to human activities associated with industrialization.

关键词： heavy metals sediment origin Qiongzhou Strait

Optimal Control of Slurry Pressure during Shield Tunnelling Based on Random Forest and Particle Swarm Optimization

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2021年第7期128卷 109-127页

作者： weiping Luo Dajun Yuan Dalong Jin Ping Lu Jian Chen Key Laboratory of Urban Underground Engineering of the Education Ministry Beijing Jiaotong UniversityBeijing100044China School of Civil Engineering Beijing Jiaotong UniversityBeijing100044China China Railway 14 Bureau Group Co. Ltd.Jinan250101China

The control of slurry pressure aiming to be consistent with the external water and earth pressure during shield tunnelling has great significance for face stability,especially in urban areas or underwater where the surrounding environment is very sensitive to the fluctuation of slurry *** this study,an optimal control method for slurry pressure during shield tunnelling is developed,which is composed of an identifier and a *** established identifier based on the random forest(RF)can describe the complex non-linear relationship between slurry pressure and its influencing *** proposed controller based on particle swarm optimization(PSO)can optimize the key factor to precisely control the slurry pressure at the normal state of advancement.A data set from Tsinghua Yuan Tunnel in China was used to train the RF model and several performance measures like R2,RMSE,etc.,were employed to ***,the hybrid RF-PSO control method is adopted to optimize the control of slurry *** good agreement between optimized slurry pressure and expected values demonstrates a high identifying and control precision.

关键词： Shield tunnelling slurry pressure optimal control random forest particle swarm optimization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

混合润滑状态下非高斯表面法向接触刚度研究

机械科学与技术 2024年第8期43卷 1386-1393页

作者：高志强席云鹏彭丽霞傅卫平王雯王双琦西安理工大学机械与精密仪器工程学院西安710048

为了揭示混合润滑状态下表面形貌特征对接触特性的影响,针对微凸体高度非高斯分布粗糙表面在法向静载荷作用下的固-液接触问题展开研究。固-液接触结合面包括微凸体的固体接触和润滑介质的流体接触。对于固体接触部分,基于弹塑性固体力... 详细信息

为了揭示混合润滑状态下表面形貌特征对接触特性的影响,针对微凸体高度非高斯分布粗糙表面在法向静载荷作用下的固-液接触问题展开研究。固-液接触结合面包括微凸体的固体接触和润滑介质的流体接触。对于固体接触部分,基于弹塑性固体力学对非高斯等效粗糙表面接触展开接触特性分析,建立了考虑微凸体弹塑性变形的非高斯粗糙表面法向接触刚度计算模型;对于流体接触部分,提出了一种考虑微凸体峰度/偏度分布影响的密闭油坑接触模型。通过仿真分析,揭示了法向压力、非高斯表面粗糙度参数及润滑油黏度系数对混合润滑固-液结合面法向接触刚度的影响规律,并对比分析了无润滑介质的固-固结合面和存在润滑介质时的固-液结合面法向接触刚度。研究表明:固-液和固-固结合面法向接触刚度均随着法向载荷的增大呈非线性增大,且固-液结合面相对固-固结合面的接触刚度略大;润滑介质黏度越大,接触刚度越大;非高斯分布的峰度和偏度对混合润滑结合面接触刚度具有显著影响,相对于零偏度分布的高斯分布表面,呈负偏度分布的非高斯表面通常具有较大的接触刚度;在轻载时,峰度对接触刚度的影响不容忽视。因此,通过改变接触表面峰度/偏度、增大法向载荷、提高润滑介质黏度,可有效改善混合润滑状态固-液结合面法向接触刚度。

关键词：机械结合面非高斯粗糙表面混合润滑固-液结合面接触刚度

Cooperative energy acceptor of three Yb^(3+) ions

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2018年第5期36卷 461-467页

作者： Junjie Guo Weihua Di Tuerxun Aidilibike Yangyang Li Xiaohui Liu weiping Qin state Key Laboratory on Integrated Optoelectronics College of Electronic Science ＆ Engineering Jilin University Changchun 130012 China Yili Normal university Electronic and Information Engineering Yining 835000 China

Our previous work first reported the cooperative sensitized luminescence from Cu2＋ or Pb2＋ by three clustered Yb^3＋ ions, in which three NIR photons can be converted into a high energy photon. Could a reverse process happen that a high energy photon is cut into three NIR photons？ This work demonstrated an example of three-photon quantum cutting （QC） phosphor, CaF2：Ce^3＋,Yb^3＋, in which three clustered Yb^3＋ ions （Yb^3＋-trimer） cooperatively and indirectly received a 306 nm ultraviolet （UV） photon energy transferred from a Ce^3＋ ion in 5d excited state and emitted three 975 nm near-infrared （NIR） photons. The cluster destruction experiments were designed to verify the necessity of the presence of Yb^3＋-trimers for QC. The dynamical analysis on luminescence of Ce^3＋ ions confirmed the energy transfer from Ce^3＋ ions to Yb^3＋-trimers. The doping concentration effect on luminescence was investigated. Furthermore, the maximum energy transfer （ET） efficiency and the corresponding QC efficiency were estimated to be 61% and 222%, respectively. Therefore, the reported three-photon QC phosphor has an attractive prospect in efficiently harvesting solar energy for silicon solar cells.

关键词： Cooperative acceptor Yb3+-trimer Ce^3+-yb^3+ Quantum cutting Solar cells Rare earths

Phase field simulation of interatomic potentials for double phase competition during early stage precipitation

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2011年第19期 2057-2062页

作者： DONG weiping , WANG YongXin, YANG Kun, CHEN Zheng & LU YanLi state Key Laboratory of Solidification Processing, Northwestern Polytechnical university, Xi’an 710072, China

Phase field model was employed to study the variations of interatomic potentials of Ni 3 Al (L1 2 phase) and Ni 3 V (DO 22 phase) as a function of temperature and concentration. The long-range order (LRO) parameter related interatomic potentials equations formulated by Khachaturyan were utilized to establish the inversion equations for L1 2 and DO 22 phases, with which interatomic potentials could be calculated. The interatomic potentials of Ni-Al and Ni-V exhibited approximately linear increases and decreases, individually, with enhanced Al concentration. Substituting the inverted interatomic potentials into the microscopic phase field equations led to three cases of precipitation sequence: the DO 22 phase preceded L1 2 phase precipitating at the interatomic potentials of Ni-V > Ni-Al; the vice cases; and two phases precipitated simultaneously at interatomic potentials of Ni-V and Ni-Al were equal.

关键词： phase field model L1 2 and DO 22 phases interatomic potentials double phase competition