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Performance optimization of grooved slippers for aero hydraulic pumps

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Chinese Journal of Aeronautics 2016年第3期29卷 814-823页

作者： Chen juan ma Jiming Li Jia Fu Yongling Department of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Sino-French Engineer School Beihang UniversityBeijing 100191China AVIC Xi'an Flight Automatic Control Research Institute.Xi'an 710065 China

A computational fluid dynamics （CFD） simulation method based on 3-D Navier Stokes equation and Arbitrary Lagrangian Eulerian （ALE） method is presented to analyze the grooved slip- per performance of piston pump. The moving domain of grooved slipper is transformed into a fixed reference domain by the ALE method, which makes it convenient to take the effects of rotate speed, body force, temperature, and oil viscosity into account. A geometric model to express the complex structure, which covers the orifice of piston and slipper, vented groove and the oil film, is constructed. Corresponding to different oil film thicknesses calculated in light of hydrostatic equilibrium theory and boundary conditions, a set of simulations is conducted in COMSOL to analyze the pump characteristics and effects of geometry （groove width and radius, orifice size） on these characteristics. Furthermore, the mechanics and hydraulics analyses are employed to validate the CFD model, and there is an excellent agreement between simulation and analytical results. The simulation results show that the sealing land radius, orifice size and groove width all dramatically affect the slipper behavior, and an optimum tradeoff among these factors is conducive to optimizing the pump design.

关键词： Arbitrary LagrangianEulerian (ALE) Computational fluid dynam-ics (CFD) Grooved slipper Hydraulic pump Navier-Stokes equation Performance analysis

Identification of blaIMI-mediated carbapenem-resistant Enterobacter from a duck farm in China

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Journal of Integrative Agriculture 2023年第8期22卷 2500-2508页

作者： HUANG hong-hao LU Yi-xing WU Su-juan ma Zhen-bao ZENG Dong-ping ZENG Zhen-ling National Laboratory of Safety Evaluation(Environmental Assessment)of Veterinary Drugs College of Veterinary Medicine/China National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria/Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationCollege of Veterinary MedicineSouth China Agricultural University Guangdong Haid Group Co. Ltd.Guangzhou 511400P.R.China

Carbapenem-and colistin-resistant Enterobacter has been a clinical and therapy problem in recent ***,we report the carbapenem-and colistin-resistant Enterobacter harboring bla_(IMI) isolated from intestinal samples and the environment of a duck farm in *** bla_(IMI)-positive Enterobacter isolates were resistant to carbapenem and *** bla_(IMI) subtypes were detected in different molecular categories of *** detection of the various IMI producers highlights the diversity of carbapenemases in a duck ***-genome sequencing demonstrated the bla_(IMI) genes were present in chromosomes or plasmids in these *** conjugation experiment demonstrated the ability of bla_(IMI)-carrying plasmid to transmit *** molecular evolution characteristics were examined through comparative genetic *** study demonstrated the presence of chromosomal and plasmid bla_(IMI) and the bla_(IMI)-carrying plasmid exhibits a horizontal transmission between Enterobacter and Escherichia coli *** similar genetic content was discovered between two bla_(IMI-16)-positive Enterobacter *** addition,a bla_(IMI-16)-carrying plasmid is an IncFII(Yp)plasmid,and a substantial amount of mobile genetic elements were identified around bla_(IMI-16).The IS-like elements and IncFII(Yp)plasmid are significant in the propagation of bla_(IMI).Our study provides evidence for the transmission of diverse bla_(IMI) genes in China and supplies additional reference data for bla_(IMI)-positive antimicrobialresistant *** surveys of bla_(IMI)-positive Enterobacter from animal-raising environments must be given more focus.

关键词： Enterobacter antimicrobial resistance carbapenemases colistin

BET in hematologic tumors:Immunity,pathogenesis,clinical trials and drug combinations

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Genes & Diseases 2023年第6期10卷 2306-2319页

作者： Tao ma Yan Chen Zhi-Gang Yi Yan-hong Li Jun Bai Li-juan Li Lian-Sheng Zhang Department of Hematology The Affiliated Hospital of Southwest Medical UniversityLuzhouSichuan 646000China Department of Hematology Lanzhou University Second HospitalLanzhouGansu 730000China

The bromodomain and extra-terminal(BET)proteins act as“readers”for lysine acetylation and facilitate the recruitment of transcriptional elongation *** protein is associated with transcriptional elongation of genes such as c-MYC and BCL-2,and is involved in the regulation of cell cycle and ***,BET inhibitors(BETi)have regulatory effects on immune checkpoints,immune cells,and cytokine *** role of BET proteins and BETi in a variety of tumors has been *** paper reviews the recent research progress of BET and BETi in hematologic tumors(mainly leukemia,lymphoma and multiple myeloma)from cellular level studies,animal studies,clinical trials,drug combination,*** has a promising future in hematologic tumors,and future research directions may focus on the combination with other drugs to improve the efficacy.

关键词： BET BRD4 Clinical trials Hematologic tumors Immunity MYC

Achieving nitritation at low temperatures using free ammonia inhibition on Nitrobacter and real-time control in an SBR treating landfill leachate

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Journal of Environmental Sciences 2015年第4期27卷 157-163页

作者： hongwei Sun Yongzhen Peng Shuying Wang juan ma Key Laboratory of Beijing Water Quality Science and Water Environment Recovery Engineering Beijing University of Technology School of Environmental and Municipal Engineering Lanzhou Jiaotong University

Free ammonia（FA） inhibition on nitrite-oxidized bacteria（NOB） and real-time control are used to achieve nitrogen removal from landfill leachate via nitrite pathway at low temperatures in sequencing batch reactor. The inhibition of FA on NOB activity during the aerobic period was prolonged using real-time control. The degree of nitrite accumulation was monitored along with variations of the ammonia-oxidizing bacteria and NOB population using fluorescence in situ hybridization techniques. It is demonstrated that the end-point of ammonia oxidization is detected from the on-line measured dissolved oxygen,oxidization–reduction potential, and p H signals, which could avoid the loss the FA inhibition on NOB caused by excess aeration. At low temperature（13.0–17.6°C）, the level of nitrite pathway rapidly increased from 19.8% to 90%, suggesting that nitritation was successfully started up at low temperature by applying syntrophic association of the FA inhibition and real-time control, and then this high level of nitrite pathway was stably maintained for as long as 233 days. Mechanism analysis shows that the establishment of nitritation was primarily the result of predominant ammonia-oxidizing bacteria developed in the nitrifying bacteria population compared to NOB. This was mainly due to a gradual reduction of nitrite amount that is available to provide energy for the growth of NOB,eventually leading to the elimination of NOB from the bacterial clusters in sequencing batch reactor sludge system.

关键词： Landfill leachate Nitritation Low temperature Free ammonia Inhibition AOB and NOB

Denitrifying phosphorus removal in a step-feed CAST with alternating anoxic-oxic operational strategy

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Journal of Environmental Sciences 2009年第9期21卷 1169-1174页

作者： ma juan PENG Yongzhen WANG Shuying WANG Li LIU Yangt ma Ningpin Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering College of Environmental and Energy Engineering Beijing University of Technology Beijing 100124 China. China Water Holdings Private Limited 28 Kaki Bukit Crescent Kaki Bukit Techpark I S416259 416259 Singpore.

A bench-scale cyclic activated sludge technology （CAST） was operated to study the biological phosphorus removal performance and a series of batch tests was carried out to demonstrate the accumulation of denitrifying polyphosphate-accumulating organisms （DNPAOs） in CAST system. Under all operating conditions, step-feed CAST with enough carbon sources in influent had the highest nitrogen and phosphorus removal efficiency as well as good sludge settling performance. The average removal rate of COD, NH4^＋-N, PO4^3--P and total nitrogen （TN） was 88.2%, 98.7%, 97.5% and 92.1%, respectively. The average sludge volume index （SVI） was 133 mL/g. The optimum anaerobic/aerobic/anoxic （AOA） conditions for the cultivation of DNPAOs could be achieved by alternating anoxic/oxic operational strategy, thus a significant denitrifying phosphorus removal occurred in step-feed CAST. The denitrification of NO^x--N completed quickly due to step-feed operation and enough carbon sources, which could enhance phosphorus release and further phosphorus uptake capability of the system. Batch tests also proved that polyphosphate-accumulating organisms （PAOs） in the step-feed process had strong denitrifying phosphorus removal capacity. Both nitrate and nitrite could be used as electron acceptors in denitrifying phosphorus removal. Low COD supply with step-feed operation strategy would favor DNPAOs accumulation.

关键词： cyclic activated sludge technology biological phosphorus removal denitrifying polyphosphate-accumulating organisms

Anti-parasitic effects of water-soluble alkaloid fractions from ethanolic extracts of Sophora moorcroftiana seeds in Caenorhabditis elegans

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Chinese Journal of Natural Medicines 2018年第9期16卷 665-673页

作者： LUO Yan-Ping ZHANG Yuan ZHANG Hui-Min ZHANG hong ZHANG Lin YU hong-juan CAO Ming-Qiang SHI Yan-Bin ZHI De-juan ma Xing-Ming DONG Kai-Zhong Department of Immunology School of Basic Medical Sciences Lanzhou University Lanzhou 730000 China Key Lab of Preelinical Study for New Drugs of Gansu Province Lanzhou 730000 China School of Pharmacy Lanzhou University Lanzhou 730000 China Department of Microbiology Medical College Northwest Minzu University Lanzhou 730000 China

Parasite infections of humans and animals remain a major global health problem, with limited choice of drugs being available to the treatment of parasitosis in the clinic. Sophora moorcroftiana(S. moorcroftiana) is a shrub that grows in Tibet Plateau of China. Decoction of the seeds has been used as a traditional Tibetan medicine to treat parasitosis for years. But the anti-parasitic effects of water-soluble fractions in the seeds need further investigation. In the present study, the water-soluble alkaloid fractions(E2) were obtained from S. moorcroftiana seeds by refluxing extraction with 60% ethanol and low polarity fraction(E2-a) and high polarity fraction(E2-b) were subsequently isolated from E2 using column chromatography. As a parasite model, Caenorhabditis elegans(C. elegans) were treated with different fractions and their survivals were recorded. The results showed that that E2-a induced a lower survival rate in C. elegans than E2-b and E2. The protoscoleces of Echinococcus granulosus(E. granulosus) were cultured in the presence of E2-a. Compared with E2-b and E2, protoscoleces exhibited decreased survival rate following E2-a treatment. Furtherly, the effects of E2-a on the behavior, brood size, and lifespan of the worms were investigated. Body bend frequencies of the worms treated with the high concentration of E2-a were reduced by two-thirds compared with the control group(P matodes to E2-a led to a decrease in head thrashes and pharyngeal pumps frequency(P < 0.01). E2-a treatment resulted in a significantly lower brood size(P < 0.01). Additional E2-a treatment induced a significantly shortened lifespan, compared with the control(P < 0.05). These findings indicated that water-soluble fraction E2-a from S. moorcroftiana seeds was a potential helminthic agent.

关键词： Sophora moorcroftiana Alkaloids Anthelmintics Caenorhabditis elegans Protoscoleces

^-pp and pp Elastic Scattering at High Energies

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Communications in Theoretical Physics 2007年第3X期48卷 541-544页

作者： ZHOU Li-juan ma Wei-Xing Collaboration Group of Hadron Physics and Non-perturbative QCD Study Guangxi University of Technology Liuzhou 545006 China Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100049 China

Based on the eikonalized Glauber representation of hadron-hadron scattering, we study the diffractive processes of ^-pp and pp elastic scattering at high energies. From our theoretical calculations and fits to the corresponding experimental data at high energies and all available momentum transfer, we find that the Pomeron exchange contributions play a significant role in description of differential cross section dσ/dt in the whole experimental domain. The Pomeron exchange contributions are related to multi-gluon exchanges in QCD, which are color singlet bound state of Reggeized gluons, such as tensor glueball and Odderon. Accordingly, we may claim that the ^-pp and pp diffractive processes at high energies s and moderate momentum transfer t would be a good tool to verify the existence of the color singlet multigluon bound states and to test QCD since QCD theory does predict the existence of these states. Therefore, we believe that the experimental measurement should be done for these diffractive processes.

关键词： pp and ^-pp scattering eikonalized Glauber model Reggeon and Pomeron exchanges

Pion Decay Constant and masses of Light Quarks and In-medium Goldstone Bosons

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Communications in Theoretical Physics 2006年第6期45卷 1085-1088页

Based on the fully dressed confining quark propagator, the pion decay constant fπ, local quark vacuum condensate, and the masses of light quarks and in-medlum Goldstone bosons are investigated. The pion decay constant fπ is predicted and compared with its value of experimental measurement. A great agreement is obtained. With the predicted fπ and values of Goldstone boson masses measured by experiments in free configuration the current masses of light quarks and the masses of in-medium Goldstone bosons are obtained.

关键词： pion decay constant quark propagator current mass of light quark masses of in-medium Goldstone bosons

Wear and corrosion resistance of CoCrNi composite coatings by laser cladding

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China Foundry 2022年第6期19卷 535-543页

作者： Di Jiang hong-zhi Cui Xiao-jie Song Xiao-juan Lian Xiao-feng Zhao Hao Chen Guo-liang ma School of materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China School of materials Science and Engineering Ocean University of ChinaQingdao 266100China

Two kinds of CoCrNi composite coatings,CoCrNiMo and CoCrNiMoBC,were prepared by laser cladding on the base metal of 304 stainless *** wear and corrosion properties of the coatings were studied by wear tests and electrochemical *** show that the addition of B_(4)C promotes the generation of the ceramic phase,and therefore improving the microhardness of the coating and enhancing its wear resistance,while simutaneously keeps its excellent corrosion *** dispersive X-ray spectrometry analysis shows that the chromium distribution in the two coatings is relatively uniform,which is beneficial for corrosion *** Kelvin probe microscopy results reveal that the potential difference between dendrites and interdendrites is only 20 mV,which leads to a relatively low driving force for galvanic *** through the atomic-scale high-resolution transmission electron microscopy shows that the fundamental reason for the high wear and corrosion resistance of the coating is the excellent coherent interface between the two phases,which reduces the interface energy and potential difference and thus improving its corrosion resistance.

关键词： wear corrosion laser cladding coherent boundary 304 stainless steel