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STUDY ON PREVIEW CONTROL METHOD OF ACTIVE SUSPENSION BASED ON A HALF-CAR MODEL

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Journal of Central South University 1999年第1期11卷 52-56页

作者： shaojun liu Yan Li 1. College of Mechanical and Electrical Engineering Central South University of Technology 410083 Changsha China

Previous studies have confirmed in simulation and experiment that an improved control performance can be obtained when the optimal preview control method was applied to an active suspension system for a quarter car model. In order to investigate the effectiveness not only in riding comfort but also in road handling, an half car model with the hydro pneumatic active suspension system is proposed in this study. Whole preview control method and partial preview control method, in which the road information detected by the front wheel is sent to the controller to decide the input to rear suspension, are taken into design of the active suspension control system. Results of numerical simulation show that satisfactory control efficiency could be achieved in both whole preview control and partial preview control. The comparison of results suggests that whole preview control method can provide better system performance, but the partial preview control method is superior due to its lower cost.

关键词： active suspension whole preview control partial preview control

Enhanced fatigue property by fabricating a gradient nanostructured surface layer in a reduced-activation steel

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Progress in Natural Science:Materials International 2022年第3期32卷 385-391页

作者： Yanyun Zhao Mengtian Liang shaojun liu Weihua Zhang College of Nuclear Equipment and Nuclear Engineering Yantai University International Academy of Neutron Science Institute of Nuclear Energy Safety Technology Hefei Institutes of Physical Science Chinese Academy of Sciences Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering China University of Petroleum (East China)

Reduced activation ferritic/martensitic(RAFM) steels have been selected as candidate structural materials for future advanced nuclear power systems. In the present work, the influence of a gradient nanograined surface layer on the fatigue properties of RAFM steels was studied. A gradient nanostructured(GNS) surface layer with a thickness of ～85 μm was prepared on RAFM steel utilizing surface mechanical rolling treatment(SMRT). The mean grain size was approximate 43 nm at the topmost surface and increased gradually with depth. The results of the stress-controlled tension-compression fatigue experiments showed that the fatigue life enhanced approximately 6 times in the SMRT samples compared to the corresponding base metal counterparts. The relationship between the applied stress amplitude and the fatigue lifetime, and the fracture morphology showed that the surface strengthening and strain delocalization were caused by GNS, which suppressed surface crack initiation process, and hence the fatigue properties of RAFM steels improved. In addition, the deformation compatibility in GNS and coarse-grained boundaries leading to more dislocation interactions and accumulation during the cyclic process, also plays a crucial role in enhancing the fatigue properties of RAFM steel.

关键词： Gradient nanostructure RAFM steels Surface mechanical rolling treatment Fatigue

Pod1 is involved in the sexual differentiation and gonadal development of the Nile tilapia

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Science China(Life Sciences) 2011年第11期54卷 1005-1010页

作者： LI JianZhong liu shaojun NAGAHAMA Yoshitaka Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education College of Life Sciences Hunan Normal Univer sity Changsha 410081 China Laboratory of Reproductive Biology National Institute for Basic Biology Okazaki 444-8585 Japan

Pod1 is a member of the basic helix-loop-helix(bHLH) family of transcription factors that have been implicated in the regulation of sexual differentiation and gonadal development in ***,to date,little is known about the role of Pod1 in nonmammalian vertebrate *** cloned and characterized the Pod1 gene from *** tilapia Pod1 gene contains an open reading frame(ORF) of 525 nucleotides which potentially codes for a protein with 174 amino *** alignment revealed that the deduced tilapia protein sequence shared high homology(79.5% to 90.5%) with the Pod1 sequences of other *** tissue distribution of Pod1 revealed by RT-PCR showed that it had varied expression patterns in adult *** situ hybridization was performed to examine the temporal and spatial expression patterns of Pod1 during tilapia sexual differentiation and gonadal *** the undifferentiated gonad,Pod1 was expressed in the somatic cells of both ***,Pod1 expression in tilapia persisted in differentiated juvenile and adult ovary and *** data indicate for the first time that Pod1 is not only necessary for the onset of sexual differentiation,but also plays an important role in gonadal development in the teleost.

关键词： Pod1 somatic cells sexual differentiation gonadal development tilapia

Development of Mining Technology and Equipment for Seafloor Massive Sulfide Deposits

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Chinese Journal of Mechanical Engineering 2016年第5期29卷 863-870页

作者： liu shaojun HU Jianhua ZHANG Ruiqiang DAI Yu YANG Hengling College of Mechanical and Electrical Engineering Central South University Changsha 410083 China Shenzhen Research Institute Central South University Shenzhen 518000 China State Key Laboratory of Deep Sea Mineral Resources Development and Utilization Technology Changsha 410012 China

Seafloor massive sulfide（SMS） deposits which consist of Au, Ag, Cu, and other metal elements, have been a target of commercial mining in recent decades. The demand for established and reliable commercial mining system for SMS deposits is increasing within the marine mining industry. The current status and progress of mining technology and equipment for SMS deposits are introduced. First, the mining technology and other recent developments of SMS deposits are comprehensively explained and analyzed. The seafloor production tools manufactured by Nautilus Minerals and similar mining tools from Japan for SMS deposits are compared and discussed in turn. Second, SMS deposit mining technology research being conducted in China is described, and a new SMS deposits mining tool is designed according to the environmental requirement. Finally, some new trends of mining technology of SMS deposits are summarized and analyzed. All of these conclusions and results have reference value and guiding significance for the research of SMS deposit mining in China.

关键词： deep sea mining equipment mining key technology seafloor massive sulfide deposits new technology

A full-length 3D structure for MAPK/ERK kinase 2 (MEK2)

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Science China(Life Sciences) 2011年第4期54卷 336-341页

作者： LIANG Hao liu Tao CHEN FangJin liu ZhaoQing liu shaojun State Key Laboratory of Proteomics Department of Neurobiology Institute of Basic Medical Sciences Beijing 100850 China

As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse *** remains to be elucidated how so many different signals can be variously transferred by only two MEK molecules(MEK1 and MEK2) .Because of technological limitations the complete structures of the MEKs are still ***,we report the full-length structure of MEK2 obtained by homology modeling and molecular dynamics *** simulations show that the N-terminal part of MEK2 is highly flexible and this flexibility may enable MEK2 to interact with ERKs and other ligands in diverse manners that correspond to various upstream signals and downstream consequences.

关键词： MEK2 homology modeling molecular dynamics simulation 3D structure

Damage Processes of Polypropylene Fiber Reinforced Mortar in Different Fiber Content Revealed by Acoustic Emission Behavior

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Journal of Wuhan University of Technology(Materials Science) 2018年第1期33卷 155-163页

作者：王岩 CHEN Shijie XU Zhengzheng liu shaojun HU Hongxiang College of Civil and Transportation Engineering Hohai University

The performances of the cement-based materials can be improved by the incorporation of polypropylene fiber, but the damage processes become more complex with different fiber contents at the same time. The acoustic emission（AE） technology can achieve the global monitoring of internal damage in materials. The evolution process of failure mode and damage degree of polypropylene fiber reinforced mortar and concrete were analyzed by measuring the AE energy, RA value, AF value and b value. It was found that the cement matrix cracked on the initial stage, the cracks further developed on the medium stage and the fibers were pulled out on the last stage. The matrix cracked with minor injury cracks, but the fiber broke with serious damage cracks. The cumulative AE energy was proportional to the polypropylene fiber reinforced concrete and mortar＇s ductility. The damage mode and damage degree can be judged by identifying the damage stage obtained by the analysis of the AF value.

关键词： polypropylene fiber different content mortar concrete acoustic emission damage processes

Characterization of H3 methylation in regulating oocyte development in cyprinid fish

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Science China(Life Sciences) 2019年第6期62卷 829-837页

作者： Rong Zhou Rujie Shang Dingbin Gong Xiujuan Xu shaojun liu State Key Laboratory of Developmental Biology of Freshwater Fish College of Life Science Hunan Normal University

Histone post-modifications are important epigenetic markers involved in multiple cellular processes via regulation of gene transcription or remodeling of chromatin structure. Oocyte development is a critical process under rigorous control to prevent the generation of aberrant gametes. However, the regulatory mechanism of oocyte early development is not well-understood due to the tiny size and poor distinguishability of the gonad in juvenile stages. Here, two cyprinid hybrid fishes, a sterile allotriploid fish and a gynogenetic hybrid fish with delayed oocyte development, provided research models to investigate the mechanisms involved. We used cytogenetic and molecular methods to confirm the pachytene arrest of oocytes in allotriploid fish and gynogenetic hybrid fish. On the basis of these developmental differences, we screened 21 different histone H3 modifications by ELISA and found that four modifications(H3 K4 me3, H3 K9 me3, H3 K79 me, and H3 K79 me3) differed significantly in the two cyprinid hybrid fishes. Changes in histone methylation at the three residues(H3 K4, K9, K79) were caused by specific methyltransferases and demethylases. Our results provide new insights into the epigenetic regulation of oocyte early development in fish, a process critical for understanding of reproductive biology and with practical applications in the aquacultural breeding industry.

关键词： histone methylation oocyte development sterility allotriploid fish

H_∞ CONTROL OF AN ACTIVE SUSPENSION SYSTEM

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Journal of Central South University 1998年第2期10卷 61-64页

作者： shaojun liu Jue Zhong Hironao Yamada Yoshikazu Suematsu 1. College of Mechanical and Engineering Central South University of Technology 410083 Changsha China 2. Nagoya University Japan

An H ∞ controller for an active suspension system is designed, which has taken the performance of ride comfort and the system robustness into account. Simulation results show that a concentrated weighting of the car body acceleration output, for the frequency where human being are most sensitive to vibration, has been executed by introducing the frequency dependent weighing function, thus the suspension acceleration frequency response characteristic can be improved. It is also pointed out that the designed controller is effective in the system robustness against the fluctuation of parameter of system.

关键词： H ∞ control active suspension ride comfort robustness

Development and application of biological technologies in fish genetic breeding

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Science China(Life Sciences) 2015年第2期58卷 187-201页

作者： XU Kang DUAN Wei XIAO Jun TAO Min ZHANG Chun liu Yun liu shaojun Key Laboratory of Protein Chemistry and Fish Developmental Biology of Ministry of Education of China College of Life SciencesHunan Normal University

Fish genetic breeding is a process that remolds heritable traits to obtain neotype and improved *** the purpose of genetic improvement,researchers can select for desirable genetic traits,integrate a suite of traits from different donors,or alter the innate genetic traits of a *** improved varieties have,in many cases,facilitated the development of the aquaculture industry by lowering costs and increasing both quality and *** this review,we present the pertinent literatures and summarize the biological bases and application of selection breeding technologies(containing traditional selective breeding,molecular marker-assisted breeding,genome-wide selective breeding and breeding by controlling single-sex groups),integration breeding technologies(containing cross breeding,nuclear transplantation,germline stem cells and germ cells transplantation,artificial gynogenesis,artificial androgenesis and polyploid breeding)and modification breeding technologies(represented by transgenic breeding)in fish genetic ***,we discuss the progress our laboratory has made in the field of chromosomal ploidy breeding of fish,including distant hybridization,gynogenesis,and ***,we systematically summarize the research status and known problems associated with each technology.

关键词： fish genetic breeding genetic improvement biological method traits new variety