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Microstructure and mechanical properties of Mg–Zn–(Nd)–Zr alloys with different extrusion processes

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Rare Metals 2016年第11期35卷 841-849页

作者： Xin Qiu Qiang yang Zhan-Yi cao Yong-bing Liu Jian Meng Key Laboratory of Automobile Materials of Ministry of Education Department of Materials Science and EngineeringJilin University State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied ChemistryChinese Academy of Sciences

The effect of Nd addition and the influence of extrusion processes on the microstructure and mechanical properties of Mg-6Zn-0.5Zr（ZK60） and Mg-6Zn-1.5Nd-0.5Zr（ZKNd602） alloys were investigated. Nd element can obviously refine the microstructure of both as-cast and asextruded Mg-Zn-Nd-Zr alloy. All of the extruded alloys exhibit a bimodal grain structure composed of equiaxedfine recrystallized（DRXed） grains and elongated coarse un DRXed grains. It is necessary to achieve high strength,particularly the yield strength, for ZKNd602 alloy, when it is extruded with a lower extrusion temperature, a suitable extrusion ratio and a relatively lower extrusion ram speed. In this study, the ultimate tensile strength（UTS）,yield strength（YS） and elongation（El） of the extruded ZKNd602 alloy were 421 MPa, 402 MPa and 6.7 %,respectively, with extrusion temperature of 290 °C, extrusion ratio of 18：1 and a ram speed of approximate0.4 mm·s^（-1）. Meanwhile, the extrusion process has obvious effects on the room-temperature properties but weak effects on the high-temperature properties.

关键词： Magnesium alloy Rare earth element Extrusion process Microstructure Mechanical property

Effects of blade rotation angle deviations on mixed-flow pump hydraulic performance

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Science China(Technological Sciences) 2014年第7期57卷 1372-1382页

作者： bing Hao cao ShuLiang State Key Laboratory of Hydroscience and Engineering Tsinghua University

By model test and numerical simulation, this paper analyzed the effects of different blades with varying rotation angle deviations on the hydraulic performance of a mixed-flow pump. It was found that when some blades had rotation angle deviations, the hydraulic performance curves of the mixed-flow pump would move. With a positive deviation, the curves moved towards the large flow rate; with a negative deviation, the curves moved towards the small flow rate. When some blades had rotation angle deviations, the symmetry and uniformity of the pressure distribution inside the mixed-flow pump flow passage both decreased; the larger the deviation, the greater the decrease. When a single blade had a large rotation angle deviation, a rather clear low pressure area was formed, lowering the cavitation performance. When two adjacent blades changed simultaneously, under the small flow rate condition, adverse pressure gradient and flow separation occurred in the flow field, and a hump appeared in the head curve and the operation stability of the mixed-flow pump dropped significantly. Near the best efficiency point（BEP）, the simultaneous change of two alternate blades produced a more significant change of pressure in the flow passage, with an even larger area. Compared to the effect of two adjacent blades, two alternate blades, when changed simultaneously, made the mixed-flow pump slightly less efficient, but with a flatter efficiency curve and relatively wider high efficiency area. By fitting the test results, a functional relation among the BEP of the mixed-flow pump QBEP, the number of deviated blades N, and blade rotation angle deviation α was established, thus realizing an effective prediction of the BEP of the mixed-flow pump when blade rotation angles have deviations.

关键词： mixed-flow pump blade rotation angle hydraulic performance model test numerical simulation

Multi-parameter optimization design, numerical simulation and performance test of mixed-flow pump impeller

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Science China(Technological Sciences) 2013年第9期56卷 2194-2206页

作者： bing Hao cao ShuLiang State Key Laboratory of Hydroscience and Engineering Tsinghua University

On the basis of the three-dimensional design platform of the mixed-flow pump impellers, an optimization design system was developed in this paper by improving the genetic algorithm with application of both strategies of keeping the optimal individu- al and employing the niche. This system took the highest efficiency of the impeller as the optimization objective and employed P, a0, A0h and A0t, which could directly affect the shape and the position of the blade, as optimization parameters. In addition, loss model was used to obtain fast and accurate prediction of the impeller efficiency. The optimization results illustrated that this system had advantages such as high accuracy and fine convergence, thus to effectively improve the design of the mixed-flow pump impellers. Numerical simulation was applied to determine the internal flow fields of the impeller obtained by optimization design, and to analyze both the relative velocity and the pressure distributions. The test results demonstrated that the mixed flow pump had the highest efficiency of 87.2%, the wide and flat high efficiency operation zone, the relatively wide range of blade angle adjustment, fine cavitation performance and satisfied stability.

关键词： mixed-flow pump impeller optimization design performance test numerical simulation

Design optimization for a launching system with novel structure

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Defence Technology（防务技术） 2019年第5期15卷 680-689页

作者： Run-duo cao Xiao-bing Zhang School of Energy and Power Engineering Nanjing University of Science and Technology

A launching system with novel structure using optimization method is investigated to improve the muzzle velocity of guns in this *** system has two tandem chambers of which the front one is ignited first and the other is ignited after a *** launching process of this novel system is modelled and a series of different schemes are simulated,to discover the interior ballistic performance of this novel launching *** order to obtain the optimal loading conditions,an optimization model combined with the combustion model is *** optimal schemes can improve the muzzle velocity by 20.6%without changing the parameters of *** means that this novel launch system could improve the interior ballistics performance significantly and it still has considerable potential to be ameliorated.

关键词： Interior ballistics Mobile chamber Design optimization

Flow Dynamics of a Spiral-groove Dry-gas Seal

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Chinese Journal of Mechanical Engineering 2013年第1期26卷 78-84页

作者： WANG bing ZHANG Huiqiang cao Hongjun School of Aerospace Tsinghua University Beijing 3E Energy Key Laboratory Tsinghua University

The dry-gas seal has been widely used in different industries. With increased spin speed of the rotator shaft, turbulence occurs in the gas film between the stator and rotor seal faces. For the micro-scale flow in the gas film and grooves, turbulence can change the pressure distribution of the gas film. Hence, the seal performance is influenced. However, turbulence effects and methods for their evaluation are not considered in the existing industrial designs of dry-gas seal. The present paper numerically obtains the turbulent flow fields of a spiral-groove dry-gas seal to analyze turbulence effects on seal performance. The direct numerical simulation （DNS） and Reynolds-averaged Navier-Stokes （RANS） methods are utilized to predict the velocity field properties in the grooves and gas film. The key performance parameter, open force, is obtained by integrating the pressure distribution, and the obtained result is in good agreement with the experimental data of other researchers. Very large velocity gradients are found in the sealing gas film because of the geometrical effects of the grooves. Considering turbulence effects, the calculation results show that both the gas film pressure and open force decrease. The RANS method underestimates the performance, compared with the DNS. The solution of the conventional Reynolds lubrication equation without turbulence effects suffers from significant calculation errors and a small application scope. The present study helps elucidate the physical mechanism of the hydrodynamic effects of grooves for improving and optimizing the industrial design or seal face pattern of a dry-gas seal.

关键词： flow dynamics spiral-groove dry-gas seal turbulence effects direct numerical simulation (DNS),Reynolds-averaged Navier-Stokes (RANS) method Reynolds lubrication equation

Mechanical Properties and Microcosmic Properties of Self-Compacting Concrete Modified by Compound Admixtures

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Journal of Renewable Materials 2022年第4期10卷 897-908页

作者： Song yang bing Qi Zubin Ai Zhensheng cao Shiqin He Lijun Li Power China Roadbridge Group Co. Ltd.Beijing100048China College of Civil Engineering North China University of TechnologyBeijing100043China Sichuan Tieke New Building Materials Co. Ltd.Chengdu610000China

It has become a research hotspot to explore raw material substitutes of *** is important to research the mechanical properties of self-compacting concrete(SCC)with slag powder(SP)and rubber particle(RP)replacing cement and coarse aggregate,respectively.12 kinds of composite modified self-compacting concrete(CMSCC)specimens were prepared by using 10%,20%and 30%SP and 30%,40%,50%and 60%*** rheological properties,mechanical properties and microstructure of the CMSCC were *** indicate that the workability,compressive strength,splitting tensile strength and flexural strength of CMSCC prepared by 20%SP and less than 40%RP are *** order to maximize the utilization of waste materials,20%SP and 40%RP can be used as the optimal ratio of the combined *** microstructure shows that the addition of proper amount of SP is conducive to the formation of increasingly more uniform C-S-H gel.C-SH gel can fill the internal pores of the sample and enhance the adhesion between the aggregate,thus improving the mechanical properties of *** has a rougher surface and lower density and stiffness,which inhibits the workability and mechanical properties of *** above research results have important theoretical and practical significance for the selection of raw materials of self-compacting concrete and the rational use of industrial wastes.

关键词： Self-compacting concrete slag powder rubber particle mechanical properties microstructure

Synthesis,pharmacokinetics and in vivo antifungal activity of the novel water-soluble prodrugs of itraconazole analogue YL-24

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Chinese Chemical Letters 2013年第4期24卷 321-324页

作者： Yu Liu Xu-Feng cao Xin Liu Yong-bing cao Wen-Jing Chu Yu-She yang State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of Sciences School of Pharmacy Second Military Medical University State Key Laboratory of Drug Research Shanghai Institute of Materia MedicoChinese Academy of Sciences

To improve the aqueous solubility of an itraconazole analogue, compound 1 （YL-24）, a series of novel prodrugs were synthesized. Among these prodrugs, the phosphate disodium salt compound 7 exhibited excellent aqueous solubility （9.8 mg/mL） at near-neutral pH and sufficient stability in buffer solutions, along with favorable pharmacokinetic profiles. In particular, compounds 1 and 7 provided moderate survival efficacy in murine systemic Candida albicans SC5314 infection model, but their efficacy was weaker than that of fluconazole.

关键词： SynthesisAntifungalWater-soluble prodrugsltraconazole analogue

The mechanisms of traditional Chinese medicine underlying the prevention and treatment of atherosclerosis

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Chinese Journal of Natural Medicines 2019年第6期17卷 401-412页

作者： LI Ting-Ting WANG Zhi-Bin LI yang cao Feng yang bing-You KUANG Hai-Xue Key Laboratory of Chinese Materia Medica (Ministry of Education) Heilongjiang University of Chinese Medicine

Atherosclerosis(AS) is a chronic inflammatory disease associated with high morbidity and mortality. The incidence of AS is increasing in the last decades. So development of safe and effective therapeutics for treating AS has become prominently important. Although there are numerous chemical drugs available for treating AS, some drugs are not effective and some have serious side effects. Traditional Chinese medicine(TCM) has a long history for the prevention and treatment of AS due to its less side effects and superior efficacy. This paper describes the effectiveness and underlying mechanisms for prevention and treatment of AS by TCM or its active components. Some TCM, e.g. XuemaiNing, Tongxinluo and Salvia miltiorrhiza have been reported to have cardio-protective effect. Some active components of TCM, e.g. saikosaponin-A, kuwanon G, luteolin and β-elemene have been isolated from various TCM and demonstrated to have beneficial effects on prevention and treatment of AS.

关键词： Atherosclerosis Traditional Chinese medicine Mechanism

Geochemical Characteristics of the Upper Permian Longtan Formation from Northeastern Sichuan Basin:Implications for the Depositional Environment and Organic Matter Enrichment

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Acta Geologica Sinica(English Edition) 2023年第4期97卷 1196-1213页

作者： XIAO Wei ZHANG bing yang Kai WANG Yan WEN Siyu MA Kai cao Gaoquan Earth Exploration and Information Technology Key Laboratory of Ministry of Education Chengdu University of TechnologyChengdu 610059China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu 610059China Institute of sedimentary geology Chengdu University of TechnologyChengdu 610059China

A set of organic-rich shales of the upper Permian Longtan Formation,which is widely developed in the northeastern part of the Sichuan Basin,is a key formation for the next step of exploration and *** present,most studies on this set of formations have focused on the reservoir characteristics and reservoir formation mechanism of the shales,and basic studies on the palaeoenvironment and organic matter(OM)enrichment mechanism have not been fully carried *** this paper,we recovered the sedimentary palaeoenvironment by mineralogical,elemental geochemical and organic geochemical analyses,and explored the enrichment mechanism of OM under the constraints of palaeoenvironmental *** shales can be divided into two stages of sedimentary evolution:compared with the shales of the Lower Longtan Formation,the shales of the Upper Longtan Formation are relatively rich in quartz,poor in clay and carbonate minerals,and the OM type changes from typeⅢto typeⅡ_(2).The depositional environment has undergone a change from sea level rise,from warm and wet climate to dry and cold climate,and from oxygen-poor condition restricted to open reduction environment;the land source input has decreased,the siliceous mineral content has increased,the biological productivity has improved,and the deposition rate has changed from high to low.A depositional model was established for the shales of the Longtan Formation,reflecting the differential reservoir formation pattern of organic *** the Lower Longtan Formation shales,the most important factors controlling OM content are terrestrial source input and deposition rate,followed by paleoclimate and paleooxygen *** the Upper Longtan Formation shales,the most important controlling factor is paleo-productivity,followed by sedimentation *** depositional model constructed for the Upper and Lower Longtan Formation shales can reproduce the enrichment of organic matter and provide a basis for later exploration and deve

关键词： geochemical characteristics sedimentary environment organic matter accumulation upper Permian northeastern Sichuan Basin