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A Multi-mode Electronic Load Sensing Control Scheme with Power Limitation and Pressure Cut-off for Mobile Machinery

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 157-170页

作者： min Cheng Bolin Sun Ruqi Ding Bing xu State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing400044China Key Laboratory of Conveyance and Equipment Ministry of EducationEast China Jiaotong UniversityNanchang330052China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou310027China

In mobile machinery,hydro-mechanical pumps are increasingly replaced by electronically controlled pumps to improve the automation level,but diversified control functions(e.g.,power limitation and pressure cut-off)are integrated into the electronic controller only from the pump level,leading to the potential instability of the overall *** solve this problem,a multi-mode electrohydraulic load sensing(MELS)control scheme is proposed especially considering the switching stability from the system level,which includes four working modes of flow control,load sensing,power limitation,and pressure *** on the actual working requirements,the switching rules for the different modes and the switching direction(i.e.,the modes can be switched bilaterally or unilaterally)are *** priority of different modes is also defined,from high to low:pressure control,power limitation,load sensing,and flow *** multiple switching rules are satisfied at the same time,the system switches to the control mode with the highest *** addition,the switching stability between flow control and pressure control modes is analyzed,and the controller parameters that guarantee the switching stability are obtained.A comparative study is carried out based on a test rig with a 2-ton hydraulic *** results show that the MELS controller can achieve the control functions of proper flow supplement,power limitation,and pressure cut-off,which has good stability performance when switching between different control *** research proposes the MELS control method that realizes the stability of multi-mode switching of the hydraulic system of mobile machinery under different working conditions.

关键词： Hydraulic control Load sensing Multi-Mode Power limitation Mobile machinery

Identification and comparison of long non-coding RNAs in the silk gland between domestic and wild silkworms

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Insect Science 2018年第4期25卷 604-616页

作者： Qiu-Zhong Zhou shou-min Fang Qiang Zhang Quan-You Yu Ze Zhang Laboratory of Evolutionary and Functional Genomics School of Life Sciences Chongqing University Chongqing China College of Life Science China West Normal University Nanchong Sichuan China

Under long-term artificial selection, the domestic silkworm （Bombyx mori） has increased its silk yield tremendously in comparison with its wild progenitor, Bombyx mandarina. However, the molecular mechanism of silk yield increase is still unknown. Comparative analysis of long non-coding RNAs （lncRNAs） may provide some insights into understanding this phenotypic variation. In this study, using RNA sequencing technology data of silk gland in domestic and wild silkworms, we identified 599 lncRNAs in the silk gland of the silkworm. Compared with protein-coding genes, the silk gland lncRNA genes tend to have fewer exon numbers, shorter transcript length and lower GC-content. Moreover, we found that three lncRNA genes are significantly and differentially expressed between domestic and wild silkworms. The potential targets of two differentially expressed lncRNAs （DELs）（dw4sg_0040 and dw4sg_0483） and the expression-correlated genes with the two DELs are mainly enriched in the related processes of silk protein translation. This implies that these DELs may affect the phenotypic variation in silk yield between the domestic and wild silkworms through the post-transcriptional regulation of silk protein.

关键词： domestication long non-coding RNAs RNA-seq silkworm silk gland transcriptome

A multi-fidelity simulation method research on front variable area bypass injector of an adaptive cycle engine

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Chinese Journal of Aeronautics 2022年第4期35卷 202-219页

作者： Zhewen xu ming LI Hailong TANG min CHEN School of Energy and Power Engineering Beihang UniversityBeijing 100083China Aero Engine Academy of China Beijing 101300China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China

Front Variable Area Bypass Injector(Front-VABI) is a component of the Adaptive Cycle Engine(ACE) with important variable-cycle features. The performance of Front-VABI has a direct impact on the performance and stability of ACE, but the current ACE performance model uses approximate models for Front-VABI performance calculation. In this work, a multi-fidelity simulation based on a de-coupled method is developed which delivers a more accurate calculation of the Front-VABI performance based on Computational Fluid Dynamics(CFD) simulation. This simulation method proposes a form of Front-VABI characteristic and its matching calculation method between it and the ACE performance model, constructs a coupling method between the(2-D) Front-VABI model and the(0-D) ACE performance model. The result shows, when ACE works in triple bypass mode, the approximate model cannot account for the effect of FrontVABI pressure loss on Core Driven Fan Stage(CDFS) design pressure ratio, and the calculated error of high-pressure turbine inlet total temperature is more than 40 K in mode transition condition(the transition operating condition between triple bypass mode and double bypass mode). In double bypass mode, the approximate model can better simulate the performance of FrontVABI by considering the local loss of area expansion. This method can be applied to the performance-optimized design of Front-VABI and the ACE control law design during mode transition.

关键词： Adaptive cycle engine Computational fluid dynamics Front variable area bypass injector Multi-fidelity simulation Performance model

Growth kinetics of cubic carbide free layers in graded cemented carbides

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International Journal of minerals,Metallurgy and Materials 2012年第1期19卷 64-71页

作者： Liu-yong Shi Yi-min Liu Ji-hua Huang shou-quan Zhang Xing-ke Zhao School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China College of Mechanical and Electrical engineering Hainen University Danzhou 571737 China Xiarnen Golden Egret Special Alloy Co. Ltd. Xiamen 361006 China

In order to reveal the formation mechanism of cubic carbide free layers （CCFL）, graded cemented carbides with CCFL in the surface zone were fabricated by a one-step sintering procedure in vacuum, and the analysis on microstructure and element distribution were performed by scanning electron microscopy （SEM） and electron probe micro-analyzer （EPMA）, respectively. A new physical model and ki- netic equation were established based on experimental results. Being different f^om previous models, this model suggests that nitrogen diffu- sion outward is only considered as an induction factor, and the diffusion of titanium through liquid phase plays a dominative role. The driving force of diffusion is expressed as the differential value between nitrogen partial pressure and nitrogen equilibrium pressure essentially. Simulation results by the kinetic equation are in good agreement with experimental values, and the effect of process parameters on the growth kinetics of CCFL can also be explained reasonably by the current model.

关键词： graded materials cemented carbides diffusion kinetics

Implant site development using titanium plate and platelet-rich fibrin for congenitally missed maxillary lateral incisors:A case report

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World Journal of Clinical Cases 2022年第6期10卷 2015-2022页

作者： Tian-shou Zhang Mahmoud Mudalal Si-Cong Ren Yan-min Zhou Department of Prosthodontics School and Hospital of StomatologyJilin UniversityChangchun 130021Jilin ProvinceChina Department of Dental Implantology School and Hospital of StomatologyJilin UniversityChangchun 130021Jilin ProvinceChina Department of Oral and Maxillofacial Surgery and Periodontology Faculty of DentistryThe Arab American UniversityJenin 240Palestine

BACKGROUND Bone deficiency and soft tissue atrophy in the absence of maxillary lateral incisors are among the most challenging problems for implant *** bone grafting is the gold standard for bone augmentation,but not without ***-rich fibrin(PRF),a biodegradable autologous biomaterial,has been widely used for bone and soft tissue ***,titanium plate is an advantageous barrier due to its good space-maintaining ***,there is a lack of literature on implant site development using titanium plate and PRF for congenitally missing maxillary lateral *** SUMMARY The patient was a 19-year-old girl with a congenitally missing tooth(#12).She underwent implant placement and simultaneous autologous bone grafting with titanium plate and *** the follow-up visit 15 d post-procedure,the vascularization of soft tissue was *** was no swelling or pain after the *** months postoperatively,bone regeneration was ***,the definitive restoration was placed,and the patient was satisfied with the esthetic *** Implant site development using titanium plate and PRF for congenitally missing maxillary lateral incisors is a feasible *** this case,the labial bone plate was displaced but remained connected to the base bone,ensuring blood *** titanium plate fixed the labial bone plate and maintained the osteogenic space,while the PRF provided growth factors and leukocytes for bone and soft tissue ***,the procedure reduced the surgical complexity and adverse reactions,displaying outstanding esthetic outcomes.

关键词： Implant placement Platelet-rich fibrin Missing incisor Bone augmentation Soft tissue regeneration Case report

Seasonal and interannual variations of flow discharge from Pearl River into sea

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Water Science and Engineering 2012年第4期5卷 399-409页

作者： Wei ZHANG shou-sheng MU Yan-jing ZHANG Kai-min CHEN State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University College of Harbour Coastal and Offshore EngineeringHohai University China Institute of Water Resources and Hydropower Research

Flow discharge from the river basin into the sea has severe impacts on the immediate vicinity of river channels, estuaries, and coastal areas. This paper analyzes the features and temporal trends of flow discharge at Pearl River＇s three main gauge stations： the Wuzhou, Shijiao, and Boluo gauge stations on the West River, North River, and East River, respectively. The results show no significant trend in annual mean discharge into the sea at the three gauge stations. Changes of monthly mean discharge at the Boluo Gauge Station are evident, and a majority of monthly discharge in the dry season displays significant increasing trends. Furthermore, changes of the extreme discharge are quite evident, with a significant decreasing trend in the annual maximum discharge and a significant increasing trend in the minimum one. The significantly decreasing ratio of the flood discharge to annual discharge at the Boluo Gauge Station indicates that the flow discharge from the East River has increased in the dry season and decreased in the flood season since the construction of dams and reservoirs. At the other two gauge stations, the Wuzhou and Shijiao gauge stations, the seasonal discharge generally does not change perceptibly. Human impacts, especially those pertaining to reservoir and dam construction, appear to be responsible for the seasonal variation of flow discharge. The results indicate that the construction and operation of dams and reservoirs in the East River have a greater influence on flow discharge, which can well explain why the seasonal variation of flow discharge from the East River is more evident.

关键词： Pearl River flow discharge climate change, human impact dam and reservoir

Enhancement of magnetic properties and thermal stability of nanocrystalline (NdDyTb)_(12.3)(FeZrNbCu)_(81.7)B_(6.0) alloy with Co substitution

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International Journal of minerals,Metallurgy and Materials 2009年第6期16卷 696-700页

作者： Xiao-qian Bao Wei Li Jie Zhu xue-xu Gao shou-zeng Zhou State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China College of Materials Science and Engineering Yanshan University Qirdauangdao 066004 China

The major drawbacks of Nd-Fe-B magnets are relatively low Curie temperature and poor thermal stability. Ribbons with the near stoichiometric 2：14：1 composition of Nd10.8Dy0.75Tb0.75Fe79.7-xCoxZr0.8Nb0.8Cu0.4B6.0 （x=0, 3, 6, 9, 12, 15） were prepared by rapid quenching and subsequent heat treatment. The effect of Co element on the magnetic properties, thermal stability, and microstructure of the ribbons was systematically studied by vibrating sample magnetometer （VSM）, thermal magnetic analysis, atomic force microscopy （AFM）, and transmission electron microscopy （TEM）. It was found that Co substitution was significantly effective in improving the magnetic properties and the thermal stability of nanocrystalline ribbons. Although the intrinsic coercivity decreased from 1308.7 kA/m for x=0 to 817.4 kA/m for x=15, the remanence polarization and maximum energy product increased from 0.839 T and 116.5 kJ/m^3 for the Co-free samples to 1.041 T and 155.1 kJ/m^3 for the 12at% Co-substituted samples, respectively. About 10 K increase in Curie temperature was observed for the 2：14：1 phase with 1at% Co substitution. The absolute values of temperature coefficients of induction and coercivity were significantly decreased with Co substitution, which may be attractive for high operational temperature applications. The microstructure of nanocrystalline ribbons was slightly refined with Co substitution.

关键词： nanocrystalline magnets Nd-Fe-B magnets Co substitution magnetic properties thermal stability microstructure

Cathodic reaction mechanisms in CO2 corrosion of low-Cr steels

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International Journal of minerals,Metallurgy and Materials 2019年第11期26卷 1405-1414页

作者： Jin-yang Zhu Li-ning xu min-xu Lu Wei Chang National Center for Materials Service Safety University of Science and Technology BeijingBeijing 100083China Corrosion and Protection Center Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China CNOOC Research Institute Beijing 100027China

The cathodic reaction mechanisms in CO2 corrosion of low-Cr steels were investigated by potentiodynamic polarization and galvanostatic *** but different dominant cathodic reactions were observed at different p H *** the higher p H level(p H>~5),H2 CO3 reduction was the dominant cathodic *** reaction was under activation *** the lower pH level(pHminant one and the reaction was under diffusion *** the intermediate area,there was a transition region leading from one cathodic reaction to *** measured electrochemical impedance spectrum corresponded to the proposed cathodic reaction mechanisms.

关键词： low alloy steel carbon dioxide corrosion EIS cathodic reaction mechanisms

Photo-degradation of Acid-red 3B dye catalyzed by TiO_2 nanotubes

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Journal of Environmental Sciences 2006年第4期18卷 783-787页

作者： JIANG Fang ZHENG shou-rong ZHENG Zheng xu Zhao-yi WANG Yan-jin State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing 210093 China

TiO2 nanotube precursor was synthesized by the hydrothermal reaction of TiO2 powders with NaOH solution and the properties of the nanotube materials were tuned using different post-treatments. Transmission electron microscopic （TEM） observation revealed that the nanotube could be obtained by either a direct rinse with acid solution or rinse with distilled water followed by acid solution. The results of X-ray diffraction （XRD） and inductively coupled plasma （ICP） analysis indicated that the nanotube material was composed of H2Ti2O5·H2O. In addition, the photocatalytic activities of the resulting catalysts were found to be strongly dependent on the post-treatment. The results of the photocatalytic reaction showed that the degradation of Acid-red 3B dye fitted pseudo-zero-order kinetics and TiO2 nanotube prepared under direct rinse with acid solution exhibited a higher catalytic efficiency compared to other catalysts.

关键词： TiO2 nanotube Acid-red 3B photocatalysis hydrothermal reaction