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Low cycle fatigue properties and microstructure evolution at 760℃ of a single crystal superalloy

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Progress in Natural Science:Materials International 2015年第1期25卷 78-83页

作者： Zhenxue Shi Xiaoguang Wang shizhong Liu Jiarong Li Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials

Low cycle fatigue(LCF) behavior of a single crystal superalloy was investigated at 760 ℃. Microstructure evolution and fracture mechanism were studied by scanning electron microscopy(SEM) and transmission electron microscopy(TEM), respectively. The results show that the fatigue data fluctuation was small and the fatigue parameters of the alloy had been determined. On increasing the cyclic number, the alloy initially showed slight cyclic softening at the early two or three cycles and slowly hardened to some extent afterwards, then kept stable for the most of the remaining fatigue life. The LCF of the alloy at 760 ℃ can be attributed to the main elastic damage in fatigue processing. The initiation site of fatigue crack was at or near the surface of the samples. Crack propagated perpendicularly to the loading direction at first and then along {111}octahedral slip planes. The fatigue fracture mechanism was quasi-cleavage fracture. The γ'phase morphology still maintained cubic shape after fracture. There were a number of slip bands shear the γ'precipitates and γ matrix near the fracture surface of the specimen. The inhomogeneous deformation microstructure was developed by dislocation motion of cross-slip and a limited γ'precipitate shearing by slip band, stacking faults or single dislocation was observed.

关键词： Single crystal superalloy LCF Fracture mechanism Microstructure

The effect of interaction between Bacillus subtilis DBM and soil minerals on Cu(Ⅱ) and Pb(Ⅱ) adsorption

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Journal of Environmental Sciences 2019年第4期31卷 328-337页

作者： Jun Bai Yuanqing Chao Yanmei Chen shizhong Wang Rongliang Qiu School of Environmental Science and Engineering Sun Yat-sen University School of Public Health Southwest Medical University Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology Sun Yat-sen University Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation Sun Yat-sen University

The effects of interaction between Bacillus subtilis DBM and soil minerals on Cu(Ⅱ)and Pb(Ⅱ)adsorption were *** combination with DBM,the Cu(Ⅱ)and Pb(Ⅱ)adsorption capacities of kaolinite and goethite improved compared with the application of the minerals *** modeling results of potentiometric titration data proved that the site concentrations of kaolinite and goethite increased by 80%and 30%,respectively after combination with ***,the involvement of functional groups in the DBM/mineral combinations resulted in lower concentrations of observed sites than the theoretical values and led to the enhancement of desorption rates by NH_4NO_3 and EDTA-Na_*** DBM-mineral complexes might also help to prevent heavy metals from entering DBM cells to improve the survivability of DBM in heavy metal-contaminated *** the combination process,the extracellular proteins of DBM provided more binding sites for the minerals to absorb Cu(Ⅱ)and Pb(Ⅱ).In particular,an especially stable complexation site was formed between goethite and phosphodiester bonds from EPS to enhance the Pb(Ⅱ)adsorption ***,we can conclude that the DBM–mineral complexes could improve the Cu(Ⅱ)and Pb(Ⅱ)adsorption capacities of minerals and protect DBM in heavy metal-contaminated environments.

关键词： Bacillus subtilis DBM Goethite Kaolinite Cu Pb

Influence of Ru Content on Microstructural Stability and Stress Rupture Property of DD15 Alloy

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Journal of Harbin Institute of Technology(New Series) 2023年第6期30卷 29-34页

作者： Zhenxue Shi shizhong Liu Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing 100095China

A fourth generation single crystal(SC)nickel based cast superalloy DD15 with 1%Ru,3%Ru,5%Ru was prepared using vacuum induction single crystal furnace in order to optimize the properties and cost of DD15 *** exposure experiment of three alloys was conducted at 1100℃for 1000 *** stress rupture properties tests were performed at 1100℃temperature and 137 MPa *** composition optimization of Ru element in DD15 alloy had been *** was found that the alloys with different Ru contents all consist of cuboidalγ′phase embedded coherent inγ***γ′phase of the alloy all has a size of about 300-500 nm and a volume content of more than sixty *** dimension ofγ′precipitates is reduced and uniform with increase of Ru *** element can reduce the distribution ratio of high melting point element,so the microstructural stability is enhanced with Ru content *** topologically close-packed(TCP)phase precipitated in the 5%Ru alloy even after 1000 h *** stress rupture life of the alloy is significantly improved as Ru content *** raft breadth decreases slightly as Ru content *** specimen with 1%Ru and 3%Ru exhibits the presence of TCP phases and without TCP phases precipitated in fracture specimen with 5%*** density and integrity ofγ/γ′interfacial dislocation network increase as Ru content of the alloy rises.

关键词： DD15 alloy Ru element stress rupture life microstructure stability

Degradation of o-chloronitrobenzene as the sole carbon and nitrogen sources by Pseudomonas putida OCNB-1

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Journal of Environmental Sciences 2009年第1期21卷 89-95页

作者： WU Haizhen WEI Chaohai WANG Yaqin HE Qincong LIANG shizhong College of Bioscience and Engineering South China University of Technology Guangzhou 510640 China. College of Environmental Science and Engineering South China University of Technology Guangzhou 510640 China

A bacterial strain that utilized o-chloronitrobenzene （o-CNB） as the sole carbon, nitrogen and energy sources was isolated from an activated sludge collected from an industrial waste treatment plant. It was identified as Pseudomonas putida based on its morphology, physiological, and biochemical characteristics with an automatic biometrical system and the 16S rRNA sequence analysis. Microcosm study showed that the biodegradation of o-CNB was optimized at culture medium pH 8.0 and 32℃. At these conditions, the strain degraded 85% of o-CNB at a starting concentration of 1.1 mmol/L in 42 h. o-Chloroaniline was identified as the major metabolite with high performance liquid chromatography （HPLC） and gas chromatography-mass spectrometry （GC-MS）. The study showed that o-CNB degradation by Pseudomonas putida OCNB-1 was initiated by aniline dioxyenase, nitrobenzene reductase and catechol-l,2- dioxygenase.

关键词： o-chloronitrobenzene Pseudomonas putida characterization degradation

THE INITIAL CAUSE OF VERTICAL MOTIONS IN THE MANTLE AND THE ATMOSPHERE

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Journal of Geographical Sciences 1993年第4期 29-49页

作者： Wang shizhong Meteorological Bureau of Jiangsu Province

In this treatise,the initial cause of vertical and horizontal motions in fluids in gravitational field is investigated,which is the theoretical fundamental of the fluid mechanics,geology and *** is shown that there exists naturally the net lifting force in fluid acting on the fluid itself,expressed with the distribution of its density by(r2 g/8 p)/V2 p,named the UPDRAFT FORCE so as to be distinguished from the ordinary buoyancy term g(p-p0)/*** up-draft force is the initial cause or driving force that we wish to *** applications of the principle of up-draft force to the mantle in geology,a closed set of differential equations for the viscous fluid is presented,on which the proposed"up-draft force tectonic model"is based for explaining the genesis and driving force of orogeny,continental drift and collision,*** equations can be used in calculating or simulating the situations of flow in mantle if the data of variables are available.

关键词： up-draft force driving force vertical motion fluid mantle atmosphere

Enhancing mixing of cohesive particles by baffles in a rotary drum

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Particuology 2016年第2期14卷 104-110页

作者： Zhixing Zhou Jihong Li Jingzhi Zhou shizhong Li Junxiao Feng Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China Beijing Engineering Research Centre of Biofuels China MOST-USDA Joint Research Center for Biofuels Beijing 100084 China Department of Thermal Science an-d Energy Engineering School of Mechanical Engineering University of Science and Technology Beifing Beijing 100081 China

A soft-sphere discrete cohesive powder model was used to simulate the transverse mixing of particles in a rotary drum. Using this model, the effect of cohesion strength and baffle length was investigated. Mixing time （tR） and mixing entropy were used to characterize the mixing behavior. The results showed that increasing particle cohesiveness increases tR. Baffles enhanced transverse mixing, especially for high- cohesive particles. Moreover, the baffle length played a significant role on mixing. An optimized length of 0.50 （L/R） enhances transverse mixing for high-cohesive particles, Further increases in baffle length only decreases the mixing rate by impeding the surface flow layer. In contrast to high-cohesive particles, low-cohesive particles needed much shorter baffles.A soft-sphere discrete cohesive powder model was used to simulate the transverse mixing of particles in a rotary drum. Using this model, the effect of cohesion strength and baffle length was investigated. Mixing time （tR） and mixing entropy were used to characterize the mixing behavior. The results showed that increasing particle cohesiveness increases tR. Baffles enhanced transverse mixing, especially for high- cohesive particles. Moreover, the baffle length played a significant role on mixing. An optimized length of 0.50 （L/R） enhances transverse mixing for high-cohesive particles. Further increases in baffle length only decreases the mixing rate by impeding the surface flow layer. In contrast to high-cohesive particles, low-cohesive particles needed much shorter baffles.

关键词： Cohesive particles Mixing Baffles Rotary drum

Construction of hierarchical three-dimensional interspersed flower-like nickel hydroxide for asymmetric supercapacitors

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Nano Research 2017年第11期10卷 3726-3742页

作者： Wutao Wei Weihua Chen Luoyi Ding shizhong Cui Liwei Mi Center for Advanced Materials Research Zhongyuan University of Technology Zhengzhou 450007 China College of Chemistry and Molecular Engineering Zhengzhou University Zhengzhou 450001 China

Low-cost and easily obtainable electrode materials are crucial for the application of *** hydroxides have recently attracted intensive attention owning to their high theoretical specific capacitance,high redox activity,low cost,and *** this study,novel three-dimensional （3D） interspersed flower-like nickel hydroxide was assembled under mild *** ammonia was used as the precipitant and inhibitor and CTAB was used as an exfoliation agent,the obtained exfoliated ultrathin Ni（OH）2 nanosheets were assembled into 3D interspersed flower-like nickel *** this novel 3D structure,the ultrathin Ni（OH）2 nanosheets not only provided a large contact area with the electrolyte,reducing the polarization of the electrochemical reaction and providing more active sites,but also reduced the concentration polarization in the electrode solution ***,the utilization efficiency of the active material was improved,yielding a high *** electrochemical performance was improved via promoting the electrical conductivity by mixing the as-synthesized Ni（OH）2 with carbon tubes （N-4-CNT electrode）,yielding excellent specific capacitances of 2,225.1 F＆#183;g-1 at 0.5 A＆#183;g-1 in a three-electrode system and 722.0 F＆#183;g-1 at 0.2 A＆#183;g-1 in a two-electrode *** N-4-CNT//active carbon （AC） device exhibited long-term cycling performance （capacitance-retention ratio of 111.4% after 10,000 cycles at 5 A＆#183;g-1） and a high specific capacitance of 180.5 F＆#183;g-1 with a high energy density of 33.5 W＆#183;h＆#183;kg-1 and a power density of 2,251.6 W＆#183;kg-1.

关键词： energy storage hierarchical nanostructures nickel ultrathin nanosheets supercapacitors

Effects of Rhenium on Creep Rupture Life of a Single Crystal Superalloys

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Journal of Materials Science & Technology 1999年第1期15卷 53-57页

作者： Li, Jiarong Tang, Dingzhong Lao, Riling Liu, shizhong Wu, Zhongtang Inst Aeronaut Mat Beijing 100095 Peoples R China

The slabs of a single crystal superalloy were poured with 2.2%Re, 3.2%Re and 4.2%Re and other element contents of the alloys were basically kept unchanged. The effects of Re on the ultimate tensile strength, creep rupture life and rafting of a single crystal superalloy were studied. The results show that with increasing Re content the ultimate tensile strength decreases but the plasticity increases at 982 degree C/248.2 MPa, 1038 degree C/206.8 MPa and 1070 degree C/176.8 MPa for the alloy; on the microstructure aspect, with increasing the creep rupture life of the alloy the rafting is getting bigger and bigger at the same test condition, and the rafting suppresses creep and increases creep rupture life in the single crystal superalloy. (Edited author abstract) 11 Refs.

关键词： Superalloys

Numerical simulation and experimental verification of silicone oil flow over magnetic fluid under applied magnetic field

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China Particuology 2007年第1期5卷 93-102页

作者： Ruoyu Hong Zhiqiang Ren shizhong Zhang Jianmin Ding Hongzhong Li Chemical Engineering Department & Key Laboratory of Organic Synthesis Soochow University Dushuh SIP Suzhou 215123 China MPR Laboratory Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China IBM HYDA/050-3 C202 3605 Highway 52 North Rochester MN 55901 USA

Two-layer flow of magnetic fluid and non-magnetic silicone oil was simulated numerically. The continuity equation, momentum equations, kinematic equation, and magnetic potential equation were solved in two-dimensional Cartesian coordinate. PLIC （piecewise linear integration calculation） VOF （volume of fluid） scheme was employed to track the free interface. Surface tension was treated via a continuous surface force （CSF） model that ensures robustness and accuracy. The influences of applied magnetic field, inlet velocity profile, initial surface disturbance of interface and surface tension were analyzed. The computed interface shapes at different conditions were compared with experimental observation.

关键词： Magnetic fluid Volume of fluid (VOF) Two-layer flow