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37篇 您的检索式:作者名="LENG Bo"
    题名 作者 年代 出处 被引量
1Direct Yaw Moment Control for Distributed Drive Electric Vehicle Handling Performance Improvement显示文摘For a distributed drive electric vehicle(DDEV) driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control(DYC) has been widely studied and applied to vehicle stability control. Good vehicle handling performance: quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts: a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error(ITAE) function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method: yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.YU Zhuoping LENG Bo XIONG Lu FENG Yuan SHI Fenmiao 2016Chinese Journal of Mechanical Engineering2016,29,3:28
2Overexpression of cyclooxygenase-2 in human HepG2, Bel-7402 and SMMC-7721 hepatoma cell lines and mechanism of cyclooxygenase-2 selective inhibitor celecoxib-induced cell growth inhibition and apoptosis显示文摘AIM: To investigate the cyclooxygenase-2 (COX-2)expression level in human HepG2, Bel-7402 and SMMC-7721hepatoma cell lines and the molecular mechanism of COX-2 selective inhibitor celecoxib-induced cell growth inhibition and cell apoptosis.METHODS: Hepatoma cells were cultured and treated with celecoxib. Cell in situ hybridization (ISH) and immunocytochemistry were used to detect COX-2 mRNA and protein expression. Proliferating cell nuclear antigen and phosphorylated Akt were also detected by immunocytochemistry assay. Cell growth rates were assessed by 3-(4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium (MTT) bromide colorimetric assay. Celecoxibinduced cell apoptosis was measured by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and flow cytometry (FCM). The phosphorylated Akt and activated fragments of caspase-9, caspase-3 were examined by Western blotting analysis.RESULTS: Increased COX-2 mRNA and protein expression were detected in all three hepatoma cell lines. Celecoxib could significantly inhibit cell growth and the inhibitory effect was in a dose- and time-dependent manner evidenced by MTr assays and morphological changes.The apoptotic index measured by TUNEL increased correspondingly with the increased concentration of celecoxib and the reaction time. With 50 μmol/L celecoxib treatment for 24 h, the apoptotic index of HepG2, BEL-7402and SMMC-7721 cells was 25.01±3.08%, 26.40±3.05%,and 30.60±2.89%, respectively. Western blotting analysis showed remarkable activation of caspase-9, caspase-3and dephosphorylation of Akt (Thr308). Immunocytochemistry also showed the reduction of PCNA expression and phosphorylation Akt (Thr308) after treatment with celecoxib.CONCLUSION: COX-2 mRNA and protein overexpression in HepG2, Bel-7402 and SMMC-7721 cell lines correlate with the increased cell growth rate. Celecoxib can inhibit proliferation and induce apoptosis of hepatoma cell strains in a dose- and time-dependent manner.Ning-Bo Liu Tao Peng Chao Pan Yu-Yu Yao Bo Shen Jing Leng 2005World Journal of Gastroenterology2005,11,40:20
3NUMERICAL SIMULATION OF FLOW AND HEAT TRANSFER CHARA-CTERISTICS OUTSIDE A PERIODICALLY VIBRATING TUBE显示文摘Fluid flow and heat transfer characteristics outside a vibrating tube were numerically simulated by the dynamic mesh method. The mechanism of heat transfer enhancement via periodic vibration of the tube was explored by using the field synergy principle. It is found that the field synergy angle between fluid velocity vector and temperature gradient vector for a periodically vibrating tube is significantly smaller than that for a stationary tube, and it changes approximately according to the sinusoidal law in a vibration period. The effect of time phase of the vibration on the field synergy angle and convective heat transfer coefficient were also discussed. Results indicate that the vibration can enhance heat transfer and this effect is more remarkable when time phase angle ranges between 50o and 140o in a half period. Especially when the time phase angle is 90o, the average field synergy angle outside the tube reaches the minimum, which leads to the best heat transfer performance.JIANG Bo TIAN Mao-cheng LENG Xue-li TANG Yu-feng PAN Ji-hong 2008Journal of Hydrodynamics2008,20,5:14
4Aspirin inhibits proliferation of gemcitabine-resistant human pancreatic cancer cells and augments gemcitabine-induced cytotoxicity显示文摘Yan-qiu OU Wen bo ZHU Yan LI Peng-xin QIU Yi-jun HUANG Jun XIE Song-min HE Xiao-ke ZHENG Tian-dong LENG Dong XU Guang-mei YAN 2010Acta Pharmacologica Sinica2010,31,1:9
5Bunch-by-bunch beam size measurement during injection at Shanghai Synchrotron Radiation Facility显示文摘Fast beam profile measurement is important in fast beam dynamic behavior investigations. A bunch-bybunch beam size measurement system, which is presently used to measure horizontal profile, has been developed at the Shanghai Synchrotron Radiation Facility(SSRF) and is capable of measuring bunches within a separation of 2 ns.The system is based on a direct-imaging optical system and high-speed photomultiplier array detector. A high-bandwidth linear signal amplifier and acquisition module have also been designed to process bunch-by-bunch multichannel signals from the detector. The software resampling technique and principal component analysis method were developed to obtain the synchronized data and enhance the signal-to-noise ratio. The fast injection of transients was successfully captured and analyzed. Moreover, the bunchby-bunch positions and sizes exhibited strong oscillation after the injection at the horizontal betatron oscillation frequency of the SSRF storage ring, and this demonstrated the bunch-by-bunch measurement capability of our system.Han-Jiao Chen Jie Chen Bo Gao Yong-Bin Leng 2018Nuclear Science and Techniques2018,29,6:9
6The status of exploitation techniques of natural gas hydrate显示文摘Natural gas hydrate(NGH)has been widely considered as an alternative form of energy with huge potential,due to its tremendous reserves,cleanness and high energy density.Several countries involving Japan,Canada,India and China have launched national projects on the exploration and exploitation of gas hydrate resources.At the beginning of this century,an early trial production of hydrate resources was carried out in Mallik permafrost region,Canada.Japan has conducted the first field test from marine hydrates in 2013,followed by another trial in 2017.China also made its first trial production from marine hydrate sediments in 2017.Yet the low production efficiency,ice/hydrate regeneration,and sand problems are still commonly encountered;the worldwide progress is far before commercialization.Up to now,many gas production techniques have been proposed,and a few of them have been adopted in the field production tests.Nevertheless,hardly any method appears really promising;each of them shows limitations at certain conditions.Therefore,further efforts should be made on the economic efficiency as well as sustainability and environmental impacts.In this paper,the investigations on NGH exploitation techniques are comprehensively reviewed,involving depressurization,thermal stimulation,chemical inhibitor injection,CO2–CH4 exchange,their combinations,and some novel techniques.The behavior of each method and its further potential in the field test are discussed.The advantages and limitations of laboratory studies are also analyzed.The work could give some guidance in the future formulation of exploitation scheme and evaluation of gas production behavior from hydrate reservoirs.Lei Yang Yulong Liu Hanquan Zhang Bo Xiao Xianwei Guo Rupeng Wei Lei Xu Lingjie Sun Bin Yu Shudong Leng Yanghui Li 2019Chinese Journal of Chemical Engineering2019,27,9:9
7LncRNAs-directed PTEN enzymatic switch governs epithelial–mesenchymal transition显示文摘Despite the structural conservation of PTEN with dual-specificity phosphatases,there have been no reports regarding the regulatory mechanisms that underlie this potential dual-phosphatase activity.Here,we report that K27-linked polyubiquitination of PTEN at lysines 66 and 80 switches its phosphoinositide/protein tyrosine phosphatase activity to protein serine/threonine phosphatase activity.Mechanistically,high glucose,TGF-β,CTGF,SHH,and IL-6 induce the expression of a long non-coding RNA,GAEA(Glucose Aroused for EMT Activation),which associates with an RNA-binding E3 ligase,MEX3C,and enhances its enzymatic activity,leading to the K27-linked polyubiquitination of PTEN.The MEX3C-catalyzed PTEN^K27-polyUb activates its protein serine/threonine phosphatase activity and inhibits its phosphatidylinositol/protein tyrosine phosphatase activity.With this altered enzymatic activity,PTEN^K27-polyUb dephosphorylates the phosphoserine/threonine residues of TWIST1,SNAI1,and YAP1,leading to accumulation of these master regulators of EMT.Animals with genetic inhibition of PTEN^K27-polyUb,by a single nucleotide mutation generated using CRISPR/Cas9(Pten^K80R/K80R),exhibit inhibition of EMT markers during mammary gland morphogenesis in pregnancy/lactation and during cutaneous wound healing processes.Our findings illustrate an unexpected paradigm in which the lncRNA-dependent switch in PTEN protein serine/threonine phosphatase activity is important for physiological homeostasis and disease development.Qingsong Hu Chunlai Li Shouyu Wang Yajuan Li Bo Wen Yanyan Zhang Ke Liang Jun Yao Youqiong Ye Heidi Hsiao Tina K.Nguyen Peter K.Park Sergey D.Egranov David H.Hawke Jeffrey R.Marks Leng Han Mien-Chie Hung Bing Zhang Chunru Lin Liuqing Yang 2019Cell Research2019,29,4:8
8A macro-mechanical constitutive model of shape memory alloys显示文摘It is of practical interest to establish a precise constitutive model which includes the equations describing the phase transformation behaviors and thermo-mechanical processes of shape memory alloy (SMA). The microscopic mechanism of super elasticity and shape memory effect of SMA is explained based on the concept of shape memory factor defined by the author of this paper. The conventional super elasticity and shape memory effect of SMA are further unified as shape memory effect. Shape memory factor is redefined in order to make clear its physical meaning. A new shape memory evolution equation is developed to predict the phase transformation behaviors of SMA based on the differential relationship between martensitic volume fraction and phase transformation free energy and the results of DSC test. It overcomes the limitations that the previous shape memory evolution equations or phase transformation equations fail to express the influences of the phase transformation peak temperatures on the phase transformation behaviors and the transformation from twinned martensite to detwinned martensite occurring in SMA. A new macro-mechanical constitutive equation is established to predict the thermo-mechanical processes realizing the shape memory effect of SMA from the expression of Gibbs free energy. It is expanded from one-dimension to three-dimension with assuming SMA as isotropic material. All material constants in the new constitutive equation can be determined from macroscopic experiments, which makes it more easily used in practical applications.ZHOU Bo LIU YanJu LENG JinSong ZOU GuangPing 2009Science China(Physics,Mechanics & Astronomy)2009,52,9:6
9Characteristics of soil seed bank in plantation forest in the rocky mountain region of Beijing, China显示文摘We investigated characteristics (scales and composition) of soil seed banks at eight study sites in the rocky mountain region of Beijing by seed identification and germination monitoring. We also surveyed the vegetation communities at the eight study sites to explore the role of soil seed banks in vegetation restoration. The storage capacity of soil seed banks at the eight sites ranked from 766.26 to 2461.92 seeds·m -2 . A total of 23 plant species were found in soil seed banks, of which 63 80% of seeds were herbs in various soil layers and 60% of seeds were located in the soil layer at 0 5cm depth. Biodiversity indices indicated clear differences in species diversity of soil seed banks among different plant communities. The species composition of aboveground vegetation showed low similarity with that based on soil seed banks. In the above- ground plant community, the afforestation tree species showed high importance values. The plant species originating from soil seed banks represented natural regeneration, which also showed relatively high importance values. This study suggests that in the rocky mountain region of Beijing the soil seed banks played a key role in the transformation from pure plantation forest to near-natural forest, promoting natural ecological processes, and the role of the seed banks in vegetation restoration was important to the improvement of ecological restoration methods.HU Zeng-hui YANG Yang LENG Ping-sheng DOU De-quan ZHANG Bo HOU Bing-fei 2013Journal of Forestry Research2013,24,1:5
10Bioactive antiinflammatory antibacterial hemostatic citrate-based dressing with macrophage polarization regulation for accelerating wound healing and hair follicle neogenesis显示文摘The efficient cutaneous wound healing accompanied with the enhanced skin appendage regeneration is still a challenge.The bacterial infection and excessive/prolonged inflammation inhibit wound healing process and result in the scar formation.Herein,we reported an anti-inflammatory polycitrate-polyethyleneimine-Ibuprofen(PCEI)and multifunctional PCEI-based F127-ε-polypeptide-alginic(FEA)dressing(FEA-PCEI)for accelerating wound healing and hair follicle neogenesis.PCEI showed the excellent anti-inflammation function through stimulating macrophage towards anti-inflammatory M2 subtype polarization.The FEA-PCEI dressing showed the temperature-response gelation,injectability,robust antibacterial activity,light-damage-resistant,homeostasis ability,and good cytocompatibility.The optimized dosage of FEA-PCEI dressing could significantly accelerate wound healing with anti-infection ability,reduce the scar formation,and promote the hair follicle neogenesis.This study provided a wound-repairing strategy through regulating the phenotype of immune cells by the designing bioactive multifunctional biomaterials.Wenguang Liu Min Wang Wei Cheng Wen Niu Mi Chen Meng Luo Chenxi Xie Tongtong Leng Long Zhang Bo Lei 2021Bioactive Materials2021,6,3:4
11A macro-mechanical constitutive model for shape memory polymer显示文摘It is of theoretical and engineering interest to establish a macro-mechanical constitutive model of the shape memory polymer (SMP), which includes the mechanical constitutive equation and the material parameter function, from the viewpoint of practical application. In this paper, a new three-dimensional macro-mechanical constitutive equation, which describes the mechanical behaviors associated with the shape memory effect of SMP, is developed based on solid mechanics and the viscoelasticity theorem. According to the results of the DMA test, a new material parameter function is established to express the relationship of the material parameters and temperature during the glass transition of SMP. The new macro-mechanical constitutive equation and material parameter function are used to numerically simulate the process producing the shape memory effect of SMP, which includes deforming at high temperature, stress freezing, unloading at low temperature and shape recovery. They are also used to investigate and analyze the influences of loading rate and temperature change rate on the thermo-mechanical behaviors of SMP. The numerical results and the comparisons with Zhou’s material parameter function and Tobushi’s mechanical constitutive equation illustrate that the proposed three-dimensional macro-mechanical constitutive model can effectively predict the thermo-mechanical behaviors of SMP under the state of complex stress.ZHOU Bo 1,2* , LIU YanJu 3 & LENG JinSong 2 1 College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin 150001, China 2 Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin 150080, China 3 Department of Aerospace Science and Mechanics, Harbin Institute of Technology, Harbin 150001, China 2010Science China(Physics,Mechanics & Astronomy)2010,53,12:3
12Synthesis of N-methylene phosphonic chitosan(NMPCS)and its potential as gene carder显示文摘N-Methylene phosphoulc chitosan (NMPCS),an amphiphilic macromolecule with powerful chelating ability of Ca^(2+) ions,was synthesized and characterized.The physicochemical properties of NMPCS and the interactions between NMPCS and plasmid DNA were investigated by FTIR,^(13)C NMR,X-ray,agarose gel electrophorcsis retardation assay,atomic force microscopy (AFM) and circular dichroism (CD).The results suggest that at charge ratio 2:1 or above,DNA could be completely entrapped and spherical complexes with mean size of 80-210 nm were formed.Taking HeLa as host cell,luciferase expression mediated by NMPCS improved about 100 times compared to the expression mediated by chitosan.Dun Wan Zhu Jin Gen Bo Hai Ling Zhang Wen Guang Liu Xi Gang Leng Cun Xian Song Yu Ji Yin Li Ping Song Lan Xia Liu Lin Mei Xiu Lan Li Yang Zhang Kang De Yao 2007Chinese Chemical Letters2007,18,11:3
13Risk stratification in symptomatic intracranial atherosclerotic disease with conventional vascular risk factors and cerebral haemodynamics显示文摘Background and purpose Symptomatic intracranial atherosclerotic stenosis(sICAS)is associated with a considerable risk of recurrent stroke despite contemporarily optimal medical treatment.Severity of luminal stenosis in sICAS and its haemodynamic significance quantified with computational fluid dynamics(CFD)models were associated with the risk of stroke recurrence.We aimed to develop and compare stroke risk prediction nomograms in sICAS,based on vascular risk factors and these metrics.Methods Patients with 50%-99%sICAS confirmed in CT angiography(CTA)were enrolled.Conventional vascular risk factors were collected.Severity of luminal stenosis in sICAS was dichotomised as moderate(50%-69%)and severe(70%-99%).Translesional pressure ratio(PR)and wall shear stress ratio(WSSR)were quantified via CTA-based CFD modelling;the haemodynamic status of sICAS was classified as normal(normal PR&WSSR),intermediate(otherwise)and abnormal(abnormal PR&WSSR).All patients received guideline-recommended medical treatment.We developed and compared performance of nomograms composed of these variables and independent predictors identified in multivariate logistic regression,in predicting the primary outcome,recurrent ischaemic stroke in the same territory(SIT)within 1 year.Results Among 245 sICAS patients,20(8.2%)had SIT.The D2H2A nomogram,incorporating diabetes,dyslipidaemia,haemodynamic status of sICAS,hypertension and age≥50 years,showed good calibration(P for Hosmer-Lemeshow test=0.560)and discrimination(C-statistic 0.73,95%CI 0.60 to 0.85).It also had better performance in risk reclassification and provided larger net benefits in decision curve analysis,compared with nomograms composed of conventional vascular risk factors only,and plus the severity of luminal stenosis in sICAS.Sensitivity analysis in patients with anterior-circulation sICAS showed similar results.Conclusions The D2H2A nomogram,incorporating conventional vascular risk factors and the haemodynamic significance of sICAS as assessed in CFD models,could be a useful tool to stratify sICAS patients for the risk of recurrent stroke under contemporarily optimal medical treatment.Xuan Tian Hui Fang Linfang Lan Hing Lung Ip Jill Abrigo Haipeng Liu Lina Zheng Florence S Y Fan Sze Ho Ma Bonaventure Ip Bo Song Yuming Xu Jingwei Li Bing Zhang Yun Xu Yannie O Y Soo Vincent Mok Ka Sing Wong Thomas W Leung Xinyi Leng 2023Stroke & Vascular Neurology2023,8,1:2
14Cloning of Beauveria bassiana chitinase gene Bbchitl and its application to improve fungal strain virulence 显示文摘Weiguo Fang Bo Leng Yuehua Xiao 2005Applied and environmental microbiology2005,,1:1
15Cloning of Beau-veria bassiana chitinase gene bbchit1and its application to im-prove fungal strain virulence显示文摘Fang Weiguo Leng Bo Xiao Yuehua 2005Applied and Environmental Microbiology2005,71,1:1
16Nebrodeolysin, a novel hemolytic protein from mushroom Pleurotus nebrodensis with apoptosis-inducing and anti-HIV-1 effects显示文摘Hui Lv Yang Kong Qing Yao Bo Zhang Fang-wei Leng He-jiao Bian Jan Balzarini Els Van Damme Jin-ku Bao 2008Phytomedicine2008,,2:1
17Compatibilization of ethylene/maleic anhydride/glycidyl methacrylate terpolymer for poly ( phenylene sulfide )/poly ( amide-66 ) blends 显示文摘WU Bo ZHENG Xian LENG Jinhua 2012J Appl Polym Sci2012,124,:1
18Least squaresapproximations with a diverging number ofparameters显示文摘LENG Chen-lei LI Bo 2010StatisticsandProbabilityLetters2010,80,:1
19Skrinkage tuning parameter selection with adivergingnumberofparameters显示文摘WANG Han-sheng LI Bo LENG Chen-lei 2009JournaloftheRoyal Statistical Society Series B (StatisticalMethodology)2009,71,3:1
20Touschek lifetime study based on the precise bunch-by-bunch BCM system at SSRF显示文摘Continuous tracking of bunch charges is the key to maintain stable operations in a storage ring in top-up mode. Recently, a precise bunch-by-bunch beam-current measurement (BCM) system has been developed at the Shanghai Synchrotron Radiation Facility. To avoid the influence of longitudinal oscillation on the amplitudes of the sampling points, a method called two-point equilibrium sampling is introduced. The results, obtained during routine operation time, show that the relative resolution of the measurement of the bunch charges is better than 0.02%. With this high resolution, the new BCM system is able to monitor the bunch-by-bunch beam lifetime. By using the filling pattern information, the Touschek lifetime and the vacuum lifetime can also be calculated. In this paper, the principle of the new method and the experiments is presented in detail.Fang-Zhou Chen Zhi-Chu Chen Yi-Mei Zhou Ning Zhang Bo Gao Xing-Yi Xu Yong-Bin Leng 2019Nuclear Science and Techniques2019,30,9:1
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