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FPGA-based high resolution DPWM control circuit

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1136-1141页

作者： SONG Hu JIANG Naiti HU Shanshan li hongtao School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China Nanjing Marine Radar Institute Nanjing 210003China

Two improved structures of high resolution digital pulse width modulator(DPWM) control circuit are proposed. Embedded digital clock manager(DCM) blocks and digital programmable delay circuits are employed as the basic resources to construct the field-programmable gate array(FPGA)-based DPWM implementations. Detailed schemes are illustrated and the circuits have been successfully implemented on the Artix-7 FPGA device developed by Xilinx. Experimental results show that when the basic clock operates at the frequency of 200 MHz, the resolutions of the two approaches can reach 625 ps and 500 ps, respectively. Besides,the presented schemes possess other merits including flexible resolution, strong versatility and relatively good stability.

关键词： digital clock manager(DCM) digital programmable delay circuit digital pulse width modulator(DPWM)

ANALYTICAL CHIP FORMATION MODEL OF MICRO-END-MILliNG

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Chinese Journal of Mechanical Engineering 2008年第1期21卷 5-8页

作者： li Chengfeng LAI Xinmin li hongtao PENG linfa NI Jun School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200240 China Shien-Ming Wu Manufacturing Research Center University of Michigan Michigan 48109 USA

A new analytical chip formation model is proposed for micro-end-milling operations. The model calculates an instantaneous uncut chip thickness by considering the combination of exact trochoidal trajectory of the tool tip and tool run-out, while the simplified circular trajectory and the neglected run-out create negligible change in conventional-scale chip formation models. Newton-Raphson iterative method is employed during the calculation to obtain quadratic convergence. The proposed approach allows the calculation of instantaneous uncut chip thickness to be done accurately and rapidly, and the prediction accuracy of this model is also verified by comparing the simulation results to experimental cutting forces.

关键词： Chip formation End-milling Run-out

Crystallographic orientation dependence on nanoscale friction behavior of energetic β-HMX crystal

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Friction 2023年第12期11卷 2264-2277页

作者： Ying YIN hongtao li Zhihong CAO Binghong li Qingshan li Hongtu HE Jiaxin YU Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621999China Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education State Key Laboratory of Environment-friendly Energy MaterialsSouthwest University of Science and TechnologyMianyang 621010China

Tribology behaviors of energetic crystals play critical roles in the friction-induced hotspot in highenergy explosive,however,the binder and energetic crystals are not distinguished properly in previous *** this study,for the first time,the nanoscale friction ofβ-octahydro-1,3,5,7-tetranitro1,3,5,7-tetrazocine(β-HMX)crystal is studied with nanoscratch tests under the ramping load *** results show that the nanoscale friction and wear ofβ-HMX crystal,as a typical energetic material,is highly depended on the applied *** friction coefficient ofβ-HMX crystal is initially high when no discernible wear is observed,and then it decreases to a stable value which varies from~0.2 to~0.7,depending on the applied load,scratch direction,and crystal ***β-HMX(011)surfaces show weakly friction and wear anisotropy behavior;in contrast,theβ-HMX(110)surfaces show strongly friction and wear anisotropy behavior where the friction coefficient,critical load for the elastic–plastic deformation transition and plastic–cracking deformation transition,and deformation index at higher normal load are highly depended on the scratch *** analyses indicate the slip system and direction ofβ-HMX surfaces play key roles in determining the nanoscale friction and wear ofβ-HMX *** obtained results can provide deeper insight into the friction and wear of energetic crystal materials.

关键词： β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(β-HMX) nanoscratch friction wear plastic deformation

Progress in the research of GSH in cells

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Chinese Science Bulletin 2011年第28期56卷 3057-3063页

作者： ZHAO HongMei RUAN HaiHua li hongtao Tianjin Key Laboratory of Food Biotechnology College of Biotechnology and Food Science Tianjin University of Commerce Tianjin 300134China

Glutathione (GSH), γ-Glu-Cys-Gly, is one of the most abundant small non-protein thiol molecules in mammalian tissues, particu- larly in the liver. Although glutathione is present in thiol-reduced (GSH) and disulfide oxidized (GSSG) forms, the predominant form is GSH and its content can exceed 10 mmol/L in liver cells. As an important intracellular reductant, GSH has many biological functions in cells. Its major function is as an anti-oxidant as it can protect proteins from oxidation by reversible posttranslational modification (glutathionylation) and decrease reactive oxygen species-mediated damage. However, it does have numerous other functions, including to chelate metal irons; enhance the absorption of iron, selenium and calcium; participate in lipid and insulin metabolism; regulate cellular events such as gene expression, DNA and protein synthesis, cell proliferation and apoptosis, redox-dependent signal transduction pathways, cytokine production and the immune response; and control protein glutathionylation. Therefore, GSH plays important roles in cell survival and health, and an imbalance in the GSH level can lead to many diseases. In this review, we provide an overview of the function of GSH in mammalian cells and discuss future research of GSH.

关键词： GSH 细胞内哺乳动物细胞抗氧化剂信号转导通路谷胱甘肽蛋白质半胱氨酸

Spontaneous escape behavior of silver from graphite-like carbon coating and its inhibition mechanism

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Journal of Materials Science & Technology 2017年第11期33卷 1402-1408页

作者： Wenting Shao Xinyu Zhang Bailing Jiang Cancan liu hongtao li College of Materials Science and Engineering Nanjing Tech University College of Materials Science and Engineering Xi'an University of Technology

A series of silver-doped graphite-like carbon coatings was prepared on the surface of aluminum alloy using the magnetron sputtering method. The spontaneous escape behavior and inhibition mechanism of silver from graphite-like carbon coating were studied. The results showed that when the sample prepared with a 0.01-A current on the silver target was placed in an atmospheric environment for 0.5 h, an apparent silver escape phenomenon could be observed. However, the silver escape phenomenon was not observed for samples prepared with a 0.05-A current on the silver target if the sample was retained in a 10^（-1） Pa vacuum environment, even after 48 h. Compared with the sample placed in the atmospheric environment immediately after an ion plating process, the silver escape time lagged for 6 h. Nanometer-thick pure carbon coating coverage could effectively suppress silver escape. When the coating thickness reached700 nm, permanent retention of silver could be achieved in the silver-doped graphite-like carbon *** the silver residue content in the graphite-like carbon coating increased from 2.27 at.% to 5.35 at.%, the interfacial contact resistance of the coating decreased from 51mΩcm^2 to 6 mΩcm^2.

关键词： Silver Graphite-like carbon coating Spontaneous escape mechanism Inhibition mechanism Interfacial contact resistance

Characteristics and Influencing Factors of the Microbial Concentration and Activity in Atmospheric Aerosols over the South China Sea

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Journal of Ocean University of China 2021年第2期20卷 257-270页

作者： QI Jianhua YIN Yidan XIE Jiamin li Mengzhe DING Xue li hongtao Key Laboratory of Marine Environment and Ecology Ministry of EducationOcean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266100China

Oceans are important sources of microbes in atmospheric aerosols;however, information about the characteristics of airborne microbes and their influencing factors over oceans is lacking. Here we report the characteristics of the microbial abundance and activity in aerosols sampled near the sea surface over the South China Sea(SCS) from May to June 2016. The airborne microbial concentration range in the aerosols was 1.68?105 to 4.84?105 cells m-3 over the SCS, reflecting an average decrease of 40% – 54% over the SCS compared with that in the samples from the coastal region of Qingdao. About 63% – 76% of the airborne microbes occurred in coarse particles(> 2.1 ?m), with a variable size distribution over the SCS. The microbial activity range in aerosols, measured by the fluorescein diacetate(FDA) hydrolysis method, was 2.09 – 11.97 ng m-3 h-1 sodium fluorescein(SF) over the SCS, which was 15% – 79% lower than that over the coastal region. These values reflected a different spatial distribution over the SCS from that of the microbial concentration. Except for certain samples, all samples had 68% of the microbial activity occurring in coarse particles. Correlation analysis showed that the microbial abundance and activity were positively correlated with the aerosol, organic carbon(OC), and water-soluble organic carbon(WSOC) concentrations, indicating that the airborne microbes may be related to the reactions of certain water-soluble organic chemicals in the atmosphere. Moreover, the concentrations of airborne microbes were significantly negatively correlated with the horizontal offshore distance. The microbial concentration and activity were significantly correlated with wind speed.

关键词： microbes aerosols microbial activity size distribution WSOC

Regulating the non-effective carriers transport for high-performance lithium metal batteries

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Journal of Energy Chemistry 2024年第5期92卷 132-141页

作者： Simeng Wang Youchun Yu Shaotong Fu hongtao li Jiajia Huang Institute of Process Engineering Chinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Haike Group Research Institute of Innovation&Technology Dongying 257000ShangdongChina

The absence of control over carriers transport during electrochemical cycling,accompanied by the deterioration of the solid electrolyte interphase(SEI)and the growth of lithium dendrites,has hindered the development of lithium metal ***,a separator complexion consisting of polyacrylonitrile(PAN)nanofiber and MIL-101(Cr)particles prepared by electrospinning is proposed to bind the anions from the electrolyte utilizing abundant effective open metal sites in the MIL-101(Cr)particles to modulate the transport of non-effective *** binding effect of the PANM separator promotes uniform lithium metal deposition and enhances the stability of the SEI layer and long cycling stability of ultra-high nickel layered oxide *** PANM as the li||NCM96 separator enables high-voltage cycling stability,maintaining 72%capacity retention after 800 cycles at a charging and discharging rate of 0.2 C at a cut-off voltage of 4.5 V and 0°***,the excellent high-rate performance delivers a specific capacity of 156.3 mA h g^(-1) at 10 *** addition,outstanding cycling performance is realized from−20 to 60°*** separator engineering facilitates the electrochemical performance of lithium metal batteries and enlightens a facile and promising strategy to develop fast charge/discharge over a wide range of temperatures.

关键词： Functional separators Metal-organic frameworks 3D continuous ion transport networks Electrospinning lithium metal batteries

A High-Assurance Trust Model for Digital Community Control System Based on Internet of Things

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Wuhan University Journal of Natural Sciences 2016年第1期21卷 29-36页

作者： li hongtao XING Jinsheng MA Jianfeng College of Mathematics and Computer Science Shanxi Normal University School of Computer Science and Technology Xidian University

Security issues and lnternet of Things （loT） become indispensable part in digital community as loT develops with the pervasive introduction of additional ＂smart＂ sensors and devices over the last decades, and it necessitates the implementation of information security principle in digital community system. A three-level criticality model to determine the potential impact is proposed in digital community system when various devices lost in this paper. Combining the actual security requirement of digital community and characteristics of loT, a hierarchical security architecture including defense-in-deep cybersecurity and distribute secure control is proposed. A high-assurance trust model, which assumes insider compromise, which exists in the digital community, is finally proposed according to the security issues analysis.

关键词： digital community Intemet of Things(IoT) information security security architecture secure control

A theoretical derivation of the Hoek-Brown failure criterion for rock materials

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第4期7卷 361-366页

作者： Jianping Zuo Huihai liu hongtao li State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology Institute of Rock Mechanics and Fractals School of Mechanics and Civil Engineering China University of Mining and Technology Aramco Research Center

This study uses a three-dimensional crack model to theoretically derive the HoekeBrown rock failure criterion based on the linear elastic fracture theory. Specifically, we argue that a failure characteristic factor needs to exceed a critical value when macro-failure occurs. This factor is a product of the micro-failure orientation angle （characterizing the density and orientation of damaged micro-cracks） and the changing rate of the angle with respect to the major principal stress （characterizing the microscopic stability of damaged cracks）. We further demonstrate that the factor mathematically leads to the empirical HoekeBrown rock failure criterion. Thus, the proposed factor is able to successfully relate the evolution of microscopic damaged crack characteristics to macro-failure. Based on this theoretical development, we also propose a quantitative relationship between the brittleeductile transition point and confining pressure, which is consistent with experimental observations.

关键词： Failure criterionTriaxial compressionMicro-failure orientationFracture mechanicsBrittle--ductile transition