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Mechanical Strain Regulates Osteoblast Proliferation Through Ca^(2+)-CaMK-CREB Signal Pathway

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Chinese Medical Sciences Journal 2016年第2期31卷 100-106页

作者： yong Guo Qi Lv Xian-qiong Zou zhi-xiong Yan Yu-xian Yan Depantment of Bioengineering College of Biotechnology Guilin Medical University Institute of Medical Equipment Academy of Military Medical Sciences Experiment Management Center Logistical College of People Armed Police Forces

Objective To investigate the effects of mechanical strain on Ca^(2+)-calmodulin dependent kinase(CaMK)-cA MP response element binding protein(CREB) signal pathway and proliferation of osteoblasts. Methods Using a four-point bending device, MC3T3-E1 cells were exposed to mechanical tensile strains of 2500 μs and 5000 μs at 0.5 Hz respectively. The intracellular free Ca^(2+)([Ca^(2+)]i) concentration and calmodulin activity were assayed by fluorospectrophotometry, CaMK II β, CREB, and phosphorylated(activated) CREB(p-CREB) were assessed by Western blot, and cells proliferation was assayed with MTT. Pretreatment with verapamil was carried out to block Ca^(2+) channel, and inhibitor U73122 was used to inhibit phospholipase C(PLC). Results Mechanical strains of 2500 μs and 5000 μs for 1 to 10 minutes both increased [Ca^(2+)]i level of the cells. The 2500 μs strain, a periodicity of 1 h/d for 3 days, activated calmodulin, elevated protein levels of CaMK II β and p-CREB, and promoted cells proliferation, which were attenuated by pretreatment of verapamil or U73122. The effects of 5000 μs strain on calmodulin, CaMK II β, p-CREB and proliferation were contrary to 2500 μs strain. Conclusion The mechanical strain regulates osteoblasts proliferation through Ca^(2+)-Ca MK-CREB signal pathway via Ca^(2+) channel and PLC/IP_3 transduction cascades.

关键词： mechanical strain calcium phospholipase C proliferation cAMP response element binding protein

Characterization of the Grain Structures in Vacuum-Assist HighPressure Die Casting AM60B Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第7期29卷 619-628页

作者： Xiao-Bo Li Shou-Mei xiong zhi-Peng Guo School of Materials Science and Engineering Tsinghua University Key Laboratory for Advanced Materials Processing Technology Ministry of EducationTsinghua University

The structures in vacuum-assist high-pressure die casting （HPDC） AM60B alloy were studied by using an optical microscope and a scanning electron microscope with an energy dispersive spectrometer. It was found that the HPDC under the vacuum could significantly change the morphology and distribution of the microstructure. For both conventional and vacuum-assist HPDC processes, the externally solidified crystals （ESCs） tended to aggregate in the center along the thickness direction of the castings. Besides, the aggregation was more pronounced, and the number of ESCs decreased, and the ESCs tended to become smaller and more globular, as the distance between the specimen location and runner increased. Compared with the conventional castings, the vacuum-assist HPDC can significantly reduce the size and amount of ESCs, and the ESCs tended to be more globular. For the distribution of ESCs along the thickness of the specimens, the aggregation tendency was more pronounced in vacuum-assist die castings than that in conventional castings. Besides, the distribution of ESCs at different locations was more converged in the vacuum-assist HPDC than that in the conventional HPDC.

关键词： AM60B alloy Grain structure Vacuum-assist high-pressure die casting Externally solidifiedcrystals

Identification of thermal effects involved in DSC experiment on Al-Cu-Mg-Ag alloys with high Cu:Mg ratio

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International Journal of Minerals,Metallurgy and Materials 2011年第6期18卷 671-675页

作者： Jian-bo Zhang yong-an Zhang Bao-hong Zhu Feng Wang zhi-hui Li Xi-wu Li Bai-qing xiong State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Non-ferrous Metals Beijing 100088 China

Precipitation reactions in the differential scanning calorimetry （DSC） of an Al-Cu-Mg-Ag alloy were identified by analyzing the results from hardness test,electrical conductivity test,and transmission electron microscope （TEM） *** is discovered that thermal effects can be identified through selected area electron diffraction and bright-field *** reaction peaks around 171,231,and 276℃ can be attributed to a structural rearrangement of coherent zones,to the precipitation of Ω phases,and to the precipitation of Ω and θ＇ and possible combination with the transition of θ＇→θ,*** addition,the hardness and electrical conductivity of the alloy change proportionately with the progression of reactions during the heating *** phenomenon can be attributed to the evolution of the micro-structure.

关键词： aluminum alloys thermal effects identification differential scanning calorimetry microstructure

Configuration design,energy management and experimental validation of a novel series-parallel hybrid electric transit bus

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第9期10卷 1269-1276页

作者： Wei-wei xiong yong ZHANG Cheng-liang YIN Institute of Automotive Engineering Shanghai Jiao Tong University Shanghai 200240 China

This paper aims to present the configuration design approach and the energy management strategy （EMS） of a series-parallel hybrid electric transit bus （SPHEB） jointly developed by Shanghai Automotive Industry Co. Ltd. （SAIC） and Shanghai Jiao Tong University （SJTU）, China. A major feature of this SPHEB is that a novel manual transmission is designed to switch the powertrain configuration between series and parallel types. To reduce the fuel consumption as well as sustain the battery state of charge, an EMS including seven energy flow modes is designed and applied to this SPHEB. Governed by this EMS, the engine is maintained to operate in high efficiency regions. The experimental test carded on the transit bus city driving cycle is described and analyzed. The experimental results demonstrate the technical feasibility and fuel economy of this approach.

关键词： Series-parallel hybrid bus Powertrain configuration Energy management Experimental validation

Series-parallel Hybrid Vehicle Control Strategy Design and Optimization Using Real-valued Genetic Algorithm

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Chinese Journal of Mechanical Engineering 2009年第6期22卷 862-868页

作者： xiong Weiwei YIN Chengliang ZHANG yong ZHANG Jianlong Institute of Automotive Engineering Shanghai Jiao Tong University Shanghai 200240 China

Despite the series-parallel hybrid electric vehicle inherits the performance advantages from both series and parallel hybrid electric vehicle, few researches about the series-parallel hybrid electric vehicle have been revealed because of its complex co nstruction and control strategy. In this paper, a series-parallel hybrid electric bus as well as its control strategy is revealed, and a control parameter optimization approach using the real-valued genetic algorithm is proposed. The optimization objective is to minimize the fuel consumption while sustain the battery state of charge, a tangent penalty function of state of charge（SOC） is embodied in the objective function to recast this multi-objective nonlinear optimization problem as a single linear optimization problem. For this strategy, the vehicle operating mode is switched based on the vehicle speed, and an ＂optimal line＂ typed strategy is designed for the parallel control. The optimization parameters include the speed threshold for mode switching, the highest state of charge allowed, the lowest state of charge allowed and the scale factor of the engine optimal torque to the engine maximum torque at a rotational speed. They are optimized through numerical experiments based on real-value genes, arithmetic crossover and mutation operators. The hybrid bus has been evaluated at the Chinese Transit Bus City Driving Cycle via road test, in which a control area network-based monitor system was used to trace the driving schedule. The test result shows that this approach is feasible for the control parameter optimization. This approach can be applied to not only the novel construction presented in this paper, but also other types of hybrid electric vehicles.

关键词： series-parallel hybrid electric vehicle control strategy design optimization real-valued genetic algorithm

Research on automatic high velocity arc spraying technique and metastable coating materials

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Advances in Manufacturing 2013年第1期1卷 97-101页

作者： Xiu-Bing Liang yong-xiong Chen zhi-Bin Zhang Shi-Cheng Wei yong-Ming Guo Bin-Shi Xu National Engineering Research Center for Mechanical Product Remanufacturing The Academy of Armored Forces Engineering National Key Laboratory for Remanufacturing The Academy of Armored Forces Engineering College of Materials Science and Engineering Beijing University of Technology

Into the 21st century, remanufacturing engineering has been accepted by more and more people in China. Remanufacturing is an industrial maintenance technology for worn or waste electro-mechanical products using advanced technology, which means the high-level stage for the maintenance and surface engineering. In this paper, a new automotive high velocity arc spraying system was introduced. And three kinds of advanced amorphous and nanocrystalline metastable coatings were developed, including Fe, Ni and Al-based amorphous and nanocrystalline composite coatings. Their research development and applications were introduced. And the development trends of high velocity arc spraying system and advanced metastable surface protective coating materials on the remanu- facturing engineering were indicated.

关键词： Remanufacturing. Arc spraying. AmorphousNanocrystalline Coating

Effect of Sintering on Grain Boundary Microstructure and Electrical Properties of CaCu_3Ti_4O_(12) Ceramics

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Wuhan University Journal of Natural Sciences 2015年第3期20卷 255-261页

作者： YANG zhi xiong Rui City College Wuhan University of Science and Technology School of Physics and Technology/Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education Wuhan University

CaCu3Ti4O12 ceramic with a giant dielectric constant was synthesized by sol-gel method and sintered in three different sintering conditions： 1 035 ℃ for 48 h, 1 080 ℃ for 3 h and 48 h. The phase of the ceramics, the element distribution, the valance state of Ti ions at grain boundaries, and the electrical properties were characterized via X-ray diffraction（XRD）, energy dispersive X-ray analysis（EDAX）, X-ray photoelectron spectroscopy（XPS）, electrical conduction and dielectric measurement. The results demonstrate that the grain-boundary microstructure and the electrical properties are influenced by sintering conditions： 1 By raising sintering temperature, the Cu-rich and Ti-poor grain boundary was formed and grain resistivity was decreased. 2 By prolonging sintering time, the content of Ti3＋ near the grain boundary increased, leading to the decrease of the grain-boundary resistivity and the increase of the activation energy at grain boundary. The ceramic, sintering at 1 080 ℃ for 48 h, exhibited a small grain resistivity（60.5 ＊cm）, a large grain-boundary activation energy（0.42 e V）, and a significantly enhanced dielectric constant（close to 1×105 at a low frequency of 1×103 Hz）. The results of electrical properties accord with the internal boundary layer capacitor model for explaining the giant dielectric constant observed in Ca Cu3Ti4O12 ceramics.

关键词： CaCu3Ti4O12 sintering microstructure electrical conduction dielectric

Elevated temperature endurance and creep properties of extruded 2D70 Al alloy rods

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Rare Metals 2011年第3期30卷 310-315页

作者： WANG Guojun xiong Baiqing ZHANG yong＇an LI zhihui State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous Metals Beijing 100088 China Northeast Light Alloy Co. Ltd. Harbin 150060 China

The elevated temperature performances of 2D70 Al alloy hot extrusion rods after two-stage homogenization and intensive deformation were studied by measuring the elevated temperature enduring strength and the creep ultimate strength. The fracture morphology of some selected samples after testing at different elevated temperatures was observed by scanning electron microscopy （SEM）. The results indicate that, as the test temperature increases, the elevated temperature enduring strength of 2D70 Al alloy decreases gradually. In a comparison between 150 C and 240 C, the notch enduring strength drops from 375 to 185 MPa and the smooth enduring strength drops from 337 to 130 MPa. Enduring strength is not sensitive to the notch. The notch sensitivity ratio （NSR） coefficient is in the range of 1.119 to 1.423 from 150 C to 240 C. The creep test results show that, as the test temperature increases from 150 C to 240 C, the creep ultimate strength of 2D70 Al alloy rods drops gradually from 312 to 117 MPa.

关键词： aluminum alloys high temperature properties strength of materials creep notched bar tensile testing

Transformation behavior of precipitates during artificial aging at 170℃in Al-Mg-Si-Cu alloys with and without Zn addition

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Rare Metals 2021年第7期40卷 1907-1914页

作者： Shang Zhu zhi-Hui Li Li-Zhen Yan Xi-Wu Li Shu-Hui Huang Hong-Wei Yan yong-An Zhang Bai-Qing xiong State Key Laboratory of Nonferrous Metals and Processes GRIMAT Engineering Institute Co..LtdBeijing 101407China

The transformation behavior of precipitates in Al-Mg-Si-Cu alloys with and without Zn addition during artificial aging at 170℃was investigated in this *** Al-Mg-Si-Cu alloys with and without Zn addition,two types of precipitates,needle-likeβ″and lath-like L,are formed with the aging time increasing from 8 to 34 *** needle-likeβ″precipitate exhibits a Mg-to-Si atomic ratio of 1.31 which is in agreement with the theoretical ratio of1.25 forβ″(Mg5 Al2 Si4).In addition,theβ″precipitate is supposed to contain Al and *** further partitioning of Mg,Si and Cu and release of Al,the needle-likeβ″precipitate can transform to lath-like L *** L phase has significantly higher concentrations of Mg,Si and Cu and lower concentration of Al,with a higher Mg-to-Si atomic ratio(1.41)deviated from theoretical ratio ofβ″.However,the major of Zn has a random distribution in Al matrix and exhibits no significant partitioning into *** remained in matrix can enhance the transformation ofβ″precipitates to L precipitates.

关键词： Al-Mg-Si-Cu alloys Zn addition Precipitates Transformation