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13篇 您的检索式:作者名="HE Keqiang"
    题名 作者 年代 出处 被引量
1Additive manufacturing of hydroxyapatite bioceramic scaffolds: Dispersion, digital light processing, sintering, mechanical properties, and biocompatibility显示文摘Hydroxyapatite(HA)bioceramic scaffolds were fabricated by using digital light processing(DLP)based additive manufacturing.Key issues on the HA bioceramic scaffolds,including dispersion,DLP fabrication,sintering,mechanical properties,and biocompatibility were discussed in detail.Firstly,the ffects of dispersant dosage,solid loading,and sintering temperature were studied.The optimal dispersant dosage,solid loading,and sintering temperature were 2wt%,50vol%,and 1250℃,respectively.Then,the mechanical properties and biocompatibility of the HA bioceramic scaffolds were investigated.The DLP-prepared porous HA bioceramic scaffold was found to exhibit excellent mechanical properties and degradation behavior.From this study,DLP technique shows good potential for manufacturing HA bioceramic scaffolds.Chengwei FENG Keqiang ZHANG Rujie HE Guojiao DING Min XIA Xinxin JIN Chen XIE 2020Journal of Advanced Ceramics2020,9,3:12
2Progress and challenges towards additive manufacturing of SiC ceramic显示文摘Silicon carbide(SiC)ceramic and related materials are widely used in various military and engineering fields.The emergence of additive manufacturing(AM)technologies provides a new approach for the fabrication of SiC ceramic products.This article systematically reviews the additive manufacturing technologies of SiC ceramic developed in recent years,including Indirect Additive Manufacturing(Indirect AM)and Direct Additive Manufacturing(Direct AM)technologies.This review also summarizes the key scientific and technological challenges for the additive manufacturing of SiC ceramic,and also forecasts its possible future opportunities.This paper aims to provide a helpful guidance for the additive manufacturing of SiC ceramic and other structural ceramics.Rujie HE Niping ZHOU Keqiang ZHANG Xueqin ZHANG Lu ZHANG Wenqing WANG Daining FANG 2021Journal of Advanced Ceramics2021,10,4:9
3Karst Collapse Mechanism and Criterion for Its Stability显示文摘Karst collapse, caused by natural or artificial abstraction of groundwater, has been a focus of environmental geological problems for its ever-increasing hazardousness. The potential erosion theory and vacuum suction erosion theory,which reveal the origin of karst collapse macroscopically, are popularly accepted. However, a mathematic prediction criterion for karst collapse cannot be established only by these two theories. From a new perspective, this paper attempts to explain the microcosmic mechanism of karst collapse on the basis of these two theories. When the shear stress surpasses the shear strength of soil, a certain point or a certain plane in the unconsolidated soil covering karst caves will fail under the mechanical effects of water and air as well as its load-pressure, and with the increase of damaged points, a breaking plane appears and the soil on karst caves is completely damaged; as a result, the karst ground collapses. On the basis of the MohrCoulomb failure theory and previous studies, the paper presents a prediction criterion of karst collapse. Finally, by taking,for example, nine typical cases of collapse caused by pumping tests in Guizhou, the paper gives the calculation process of the model and proves its reliability.HE Keqiang LIU Changli WANG Sijing 2001Acta Geologica Sinica(English Edition)2001,75,3:5
4Influences of NiCO_3 content on the microstructure and magnetic properties of Ni_(0.5)Zn_(0.5)Fe_2O_4 powders prepared by SHS显示文摘Stoichiometric Ni0.5Zn0.5Fe2O4 powders were produced by self-propagating high temperature synthesis (SHS). The effects of NiCO3 content in the raw materials on the microstructure and magnetic properties of Ni-Zn ferrite powders were systematically studied. The Ni0.5Zn0.5Fe2O4 powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The magnetic properties of the powders were evaluated by vibrating sample magnetometry (VSM). The results show that the introduction of NiCO3 into reactants improves the con- version percentage and refines the Ni0.5Zn0.5Fe2O4 particles. The increase of NiCO3 content enhances the magnetic properties of Ni0.5Zn0.5Fe2O4. Particularly, the saturation magnetization reaches the maximum when the NiCO3 content is 3 at.%.WANG Keqiang HE Xiaodong LI Xiao JIANG Jiuxing SUN Yue 2009Rare Metals2009,28,5:2
5Comprehensive fuzzy evaluation model and evaluation of the karst collapse susceptibility in Zaozhuang Region, China显示文摘Keqiang He Yuyue Jia Bin Wang 2013Natural Hazards2013,68,2:1
6Environmental impact of drainage of Dianzi Iron Mine on the groundwater system of the Dawu Water Supply Base显示文摘He Keqiang Xu Guangming 2004Environmental Geology2004,45,8:1
7Mechanical properties of additively-manufactured cellular ceramic structures:A comprehensive study显示文摘Cellular ceramic structures(CCSs)are promising candidates for structural components in aerospace and modern industry because of their extraordinary physical and chemical properties.Herein,the CCSs with different structural parameters,i.e.,relative density,layer,size of unit cells,and structural configuration,were designed and prepared by digital light processing(DLP)-based additive manufacturing(AM)technology to investigate their responses under compressive loading systematically.It was demonstrated that as the relative density increased and the size of the unit cells decreased,the mechanical properties of one-layer CCSs increased.The mechanical properties of three-layer CCSs were more outstanding than those of the CCSs with one and two layers.In addition,structural configurations also played a vital role in the mechanical properties of the CCSs.Overall,the mechanical properties of the CCSs from superior to inferior were that with the structural configurations of modified body-centered cubic(MBCC),Octet,SchwarzP,IWP,and body-centered cubic(BCC).Furthermore,structural parameters also had significant impacts on the failure mode of the CCSs under compressive loading.As the relative density increased,the failure mode of the one-layer CCSs changed from parallel-vertical-inclined mode to parallel-vertical mode.It was worth noting that the size of the unit cells did not alter the failure mode.Inclined fracture took a greater proportion in the failure mode of the multi-layer CCSs.But it could be suppressed by the increased relative density.Similarly,the proportions of the parallel-vertical mode and the fracture along a specific plane always changed with the variation of the structural configurations.This study will serve as the base for investigating the mechanical properties of the CCSs.Xueqin ZHANG Keqiang ZHANG Bin ZHANG Ying LI Rujie HE 2022Journal of Advanced Ceramics2022,11,12:1
8Mechanism and mechanical model of karst collapse in an over - pumping area显示文摘He Keqiang Wang Bin Zhou Dunyun 2004Environmental Geology2004,46,8:1
9Quantitative characterization of defects in stereolithographic additive manufactured ceramic using X-ray computed tomography显示文摘Ceramics have been widely fabricated by additive manufacturing(AM).Compared to conventional technologies,the strength of additive manufactured ceramic is relatively low owing to the formation of defects during manufacturing process.These defects have significant effects on the microstructure and mechanical properties of additive manufactured ceramics.However,systematic research on defects,including defect geometrical features,quantitative statistics,and formation mechanism,as well as the intrinsic relationship with mechanical properties,need to be studied in depth.In this work,Al2 O3 ceramics were prepared from photosensitive slurries with different solid loadings by using stereolithographic(SL)additive manufacturing.The defects,including their sizes and distributions,in both green and sintered bodies were investigated by using scanning electron microscopy(SEM)and X-ray computed tomography(X-CT).Geometrical features and quantitative statistics of the defects were evaluated and discussed to reveal their formation mechanism.Moreover,the intrinsic relationship between defects and mechanical properties of the additive manufactured ceramic was revealed.This study can give some fundamental understanding of the defects in additive manufactured ceramics.Keqiang Zhang Qiaoyu Meng Xueqin Zhang Zhaoliang Qu Rujie He 2022Journal of Materials Science & Technology2022,,23:1
10A review of modeling,simulation,and control technologies of altitude ground test facilities for control application显示文摘As the pivotal test equipment of aero-engines design,finalization,improvement,modification,etc.,the Altitude Ground Test Facilities(AGTF)plays an important role in the research and development of the aero-engines.With the rapid development of advanced high-performance aeroengine,the increasing demand of high-altitude simulation test is driving AGTF to improve its test ability and level of automation and intelligence.The modeling method,simulation tool,and control technology are the key factors to support the improvement of the AGTF control system.The main purpose of this paper is to provide an overview of modeling methods,simulation tools,and control technologies in AGTF control system for future research.First,it reviews the evolution of AGTF in the world,from the early formative stage to integration stage.Then,the mathematical modeling method of AGTF for control application is overviewed.Furthermore,the simulation tools used in the AGTF control system are overviewed from numerical simulation to hardware-in-loop simulation and further to semi-physical simulation.Meanwhile,the control technologies used in the AGTF control system are summarized from single-variable control to multivariable integrated control,and from classical control theory to modern control theory.Finally,recommendations for future research are outlined.Therefore,this review article provides extensive literature information for the modeling,simulation,and control design of AGTF for control application.Xitong PEI Xi WANG Jiashuai LIU Meiyin ZHU Zhihong DAN Ai HE Keqiang MIAO Louyue ZHANG Zheng XU 2023Chinese Journal of Aeronautics2023,36,9:0
11Field Control Effects and Crop Safety Assessment of Triazole Fungicides on Apple Rust显示文摘In order to provide a reference basis for efficient prevention and control of apple rust,apple rust(Gymnosporangium yamadai)was used as the test material,the field control effects of six triazole fungicides with different concentrations and different application times on apple rust,and the safety of application in different periods on the crop were investigated in field trials.The results showed that the control effect and safety of myclobutanil were excellent.In the prevention test,the effects of myclobutanil 40%EC 2000 times and 4000 times dilutions in protecting apple leaves from G.yamadai infection reached more than 98%at 10 d after the second spraying in the fruitlet stage,and in the treatment test,the control effects of inhibiting the spread of leaf lesions were 90.89%and 87.17%at 16 d after the fourth spraying in the fruit expansion stage,respectively.The results of the crop safety test showed that when applying the triazole fungicides with different concentrations from the red bud stage to the fruit expansion stage of apple trees,there were no adverse effects on the leaves,branches,flowers and fruit,as well as no rust or deformity on the fruit surface.When spraying the fungicides from the red bud stage to the fruit expansion stage,except that the single fruit weights in the treatment of the 10%difenoconazole DC 2000 times and myclobutanil 40%EC 4000 times dilutions were reduced without a significant difference from the control,and the values of other treatments were all reduced by more than 9%compared with the control.When applying the fungicides during the fruit expansion period,none of the tested fungicide treatments had a significant effect on the fruit growth.He JIANG Yuxiang LU Xiaoyue CHONG Keqiang CAO Jie WEI Shutong WANG 2021Agricultural Biotechnology2021,10,3:0
12Aging-induced YTHDF aggregates impair mitochondrial function by trapping mitochondrial RNAs and suppressing their expression in the brain显示文摘DearEditor,Brain aging is associated with a decrease in cognitive function,which is often accompanied by defective changes in mitochondrial morphology and reduction in mitochondrial function(Faitg et al.,2021).The main function of mitochondria is to produce energy in the form of ATP,which is vital to fulfill high energy demand of neurons,mainly for synaptic processes(Lee et al.,2018).Mitochondrial dysfunction acts as a key factor for age-related cognitive decline(Grimm and Eckert,2017).Juan Zhang Dingfeng Li Keqiang He Qiang Liu Zhongwen Xie 2024Protein & Cell2024,15,2:0
13Multilayer dielectric grating pillar-removal damage induced by a picosecond laser显示文摘Multilayer dielectric gratings typically remove multiple-grating pillars after picosecond laser irradiation;however,the dynamic formation process of the removal is still unclear.In this study,the damage morphologies of multilayer dielectric gratings induced by an 8.6-ps laser pulse were closely examined.The damage included the removal of a single grating pillar and consecutive adjacent grating pillars and did not involve the destruction of the internal high-reflection mirror structure.Comparative analysis of the two damage morphological characteristics indicated the removal of adjacent pillars was related to an impact process caused by the eruption of localized materials from the left-hand pillar,exerting impact pressure on its adjacent pillars and eventually resulting in multiple pillar removal.A finite-element strain model was used to calculate the stress distribution of the grating after impact.According to the electric field distribution,the eruptive pressure of the dielectric materials after ionization was also simulated.The results suggest that the eruptive pressure resulted in a stress concentration at the root of the adjacent pillar that was sufficient to cause damage,corresponding to the experimental removal of the adjacent pillar from the root.This study provides further understanding of the laser-induced damage behavior of grating pillars and some insights into reducing the undesirable damage process for practical applications.Kun Shuai Xiaofeng Liu Yuanan Zhao Keqiang Qiu Dawei Li He Gong Jian Sun Li Zhou Youen Jiang Yaping Dai Jianda Shao Zhilin Xia 2022High Power Laser Science and Engineering2022,10,6:0
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