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415篇 您的检索式:作者名="Lifeng Zhang"
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1Evidence of crustal ‘channel flow’ in the eastern margin of Tibetan Plateau from MT measurements显示文摘Magnetotelluric (MT) survey has been carried out in the eastern margin of the Tibetan Plateau and its neighboring Shimian-Leshan area, Sichuan Province. Analysis of this MT data reveals that the electric structure of the Tibetan Plateau differ much from that of the Sichuan block. In general, the electric re-sistivity of crust beneath the Sichuan block in the east is larger than that of the eastern margin of the Tibetan Plateau in the west. The crust of the plateau is divided into upper, middle, and lower layers. The middle crust is a low resistivity layer with minimum down to 3―10 Ωm about 10―15 km thick. It pre-sumably contains partial melt and/or salt-bearing fluids with low viscosity, prone to deform and flow, producing a 'channel flow' under the southeastward squeeze of the eastern Tibetan Plateau. This low-resistivity layer makes the upper crust decoupled mechanically from the lower crust. In the brittle upper crust, faults are dominated by left-lateral strike-slip and thrust motions, leading to surface rising and shallow earthquakes. The low-resistivity layer also cut the Xianshuihe-Anninghe fault zone into two sections vertically. In this region, the thicknesses of upper, middle, and lower crust vary laterally, pro-ducing a transitional zone in the eastern margin of the Tibetan Plateau characterized by thicker crust and higher elevation in the west and thinner crust and lower elevation in the east.ZHAO GuoZe CHEN XiaoBin WANG LiFeng WANG JiJun TANG Ji WAN ZhanSheng ZHANG JiHong ZHAN Yan XIAO QiBin 2008Chinese Science Bulletin2008,53,12:57
2Class I phosphatidylinositol 3-kinase inhibitor LY294002 activates autophagy and induces apoptosis through p53 pathway in gastric cancer cell line SGC7901显示文摘我们试图学习 LY294002 的效果,一级 phosphatidylinositol 3-kinase (PI3K ) 的一个禁止者在增长上,在胃的癌症房间的 apoptosis,和 autophagy 衬里 SGC7901。在这研究,我们证明 LY294002 禁止了胃的癌症 SGC7901 房间的生存能力。我们也证明 LY294002 增加了 1 点亮的联系微导管的蛋白质的表示链 3 (LC3 ) ,并且增加的 monodansylcadaverine (MDC ) 把泡标记。LY294002 由激活 p53 和 caspase-3 激活 autophagy,并且由 up-regulatingp53 和 apoptosis (美洲狮) 的 p53-up-regulated 调节的人导致了 apoptosis。因此, LY294002 可能通过 p53 和下游的点美洲狮的激活在 SGC7901 房间导致 cytotoxicity。这些调查结果建议表明小径的一级 PI3K 的抑制是为管理胃的癌症的潜在的策略。Chungen Xing Baosong Zhu Huihui Liu Huihua Yao Lifeng Zhang 2008Acta Biochimica et Biophysica Sinica2008,40,3:17
3Reversal of B-cell hyperactivation and functional impairment is associated with HBsAg seroconversion in chronic hepatitis B patients显示文摘B 房间对再感染在肝炎 B 病毒(HBV ) 和保护的清理起一个重要作用。然而,与长期的 HBV 感染的结果被联系的这些房间的功能的特征仍然保持未知。我们包括地在不同阶段从 CHB 病人调查了外部 B 房间子集的频率,显型,和功能:有免疫力的忍耐(信息技术) ,有免疫力的激活(IA ) ,有免疫力的清理(IC ) ,有 HBsAg seroconversion 的应答者(解决的病人, RP ) ,并且健康控制(HC ) 。IA 病人与另外的组相比显示了外部血记忆 B 房间的更低的百分比。B 房间的全面 polyclonal 激活,由激活标记和 IgG 和 IgM 的分泌物的高水平显示了,在 IA 病人被观察。这 B 房间 hyperactivation 能被增加的 IFN-α 导致;并且在 IA 病人的可溶的 CD40 ligands。尤其是,合作激发器分子 CD80 和浆液 HBsAb 的表示和 HBsAg 特定的 B 房间的频率显著地与 HC 题目相比在信息技术, IA,和 IC 病人被减少。更重要地, B 房间 hyperactivation, co-stimulatory 分子 downregulation 和 HBsAg 特定的 B 房间缺陷在 RP 病人被颠倒。B 房间 hyperactivation 和功能的缺陷的颠倒在长期的肝炎 B 病人与 HBsAg seroconversion 被联系。Xiangsheng Xu Qinghua Shang Xinyue Chen Weimin Nie Zhengsheng Zou Ang Huang Ming Meng Lei Jin Ruonan Xu Ji-Yuan Zhang Junliang Fu Lifeng Wang Zirong Tang Yunbo Xie Xiaoming Yang Zheng Zhang Fu-Sheng Wang 2015Cellular & Molecular Immunology2015,12,3:15
4Efficacy and safety evaluation of intravenous infusion of cervus and cucumis polypeptides for treatment of avascular necrosis of the femoral head: a randomized clinical trial显示文摘OBJECTIVE: To investigate the efficacy and safety of intravenous cervus and cucumis polypeptides for treating avascular necrosis of the femoral head(ANFH) in regard to pain and hip function in a randomized clinical trial.METHODS: A total of 96 subjects with ANFH who were recruited at the Orthopaedic Hospital Affiliated with Hebei United University and Qian Hai Femoral Head Hospital of Beijing were assigned by lottery to an intervention group(n = 48) or a control group(n = 48). All subjects underwent physical therapy and rehabilitation exercises. In addition,subjects in the intervention group were given intravenous infusions of cervus and cucumis polypeptides. Visual analogue scale(VAS), Harris hip score,and radiography or magnetic resonance imaging were applied to assess all subjects at the beginning of treatment and 3, 6, and 9 months afterward. All the subjects were followed up for 2 years.RESULTS: At the beginning of treatment, there were no statistically significant differences between the two groups in terms of the general condition of patients or the VAS and Harris hip scores(all P > 0.05). At 3, 6, and 9 months after treatment,however, the VAS score decreased and the Harris hip score increased in all patients, with the improvement of intervention group significantly greater than that of the control group(P < 0.05).The total effectiveness rates for the intervention and control groups were 89.58% and 70.83%, respectively, with the difference being statistically significant(P < 0.05). There was no statistically significant difference between the two groups in terms of the safety of the injections(P > 0.05).CONCLUSION: Intravenous infusion of cervus and cucumis polypeptides relieved pain and improved hip function of subjects with ANFH.Thus, the intravenous infusion of cervus and cucumis polypeptides was a safe, effective treatment for ANFH.Wei Liyou Zhang Hongwei Li Xinmin Yang Chunyan Wang Guoqiang Zhang Lifeng Cui Mingwu Han Lijun 2016Journal of Traditional Chinese Medicine2016,36,1:15
5SHRIMP zircon U-Pb dating for gabbro from the Tiding ophiolite in Tibet显示文摘WANG Ran XIA Bin ZHOU Guoqing ZHANG Yuquan YANG Zhiqing LI Wenqian WEI Dongliang ZHONG Lifeng XU Lifeng 2006Chinese Science Bulletin2006,51,14:14
6Aspirin alleviates endothelial gap junction dysfunction through inhibition of NLRP3inflammasome activation in LPS-induced vascular injury显示文摘The loss of endothelial connective integrity and endothelial barrier dysfunction can lead to increased vascular injury, which is related to the activation of endothelial inflammasomes. There are evidences that low concentrations of aspirin can effectively prevent cardiovascular diseases. We hypothesized that low-dose aspirin could ameliorate endothelial injury by inhibiting the activation of NLRP3 inflammasomes and ultimately prevent cardiovascular diseases. Microvascular endothelial cells were stimulated by lipopolysaccharide(2 μg/mL) and administrated by 0.1–2 mmol/L aspirin. The wild type mice were stimulated with LPS(100 μg/kg/day), and 1 h later treated with aspirin(12.5, 62.5, or125 mg/kg/day) and dexamethasone(0.0182 mg/kg/day) for 7 days. Plasma and heart were harvested for measurement of ELISA and immunofluorescence analyses. We found that aspirin could inhibit NLRP3 inflammasome formation and activation in vitro in dose-dependent manner and has correlation between the NLRP3 inflammasome and the ROS/TXNIP pathway. We also found that low-concentration aspirin could inhibit the formation and activation of NLRP3 inflammasome and restore the expression of theendothelial tight junction protein zonula occludens-1/2(ZO1/2). We assume that aspirin can ameliorate the endothelial layer dysfunction by suppressing the activation of NLRP3 inflammasome.Xing Zhou Yanjiao Wu Lifeng Ye Yunting Wang Kaimin Zhang Lingjun Wang Yi Huang Lei Wang Shaoxiang Xian Yang Zhang Yang Chen 2019Acta Pharmaceutica Sinica B2019,9,4:13
7Incidence and mortality of primary bone cancers in China, 2014显示文摘Objective: In this study, we aimed to estimate the updated incidence and mortality of primary bone cancers based on population-based cancer registration data in 2014, collected by the National Central Cancer Registry of China(NCCRC).Methods: In 2017, 339 registries' data were qualified based on data quality criteria set down by the NCCRC.Cases of primary bone cancers were retrieved from the national database. We estimated numbers of primary bone cancer cases and deaths in China using age-specific rates and corresponding national population stratified by area,sex, age-group(0, 1-4, 5-9, 10-14, …, 85+). Chinese standard population in 2000 and Segi's World population were applied for the calculation of age-standardized incidence and mortality rates.Results: In 2014, 24,000 primary bone cancer cases and 17,200 deaths attributable to primary bone cancers were estimated to have occurred in China. The crude incidence rate of primary bone cancers was 1.76/100,000, with agestandardized incidence rate by Chinese standard population(ASIRC) and by World standard population(ASIRW)being 1.35/100,000 and 1.32/100,000, respectively. The crude mortality rate of primary bone cancers was1.26/100,000, with age-standardized mortality rate by Chinese standard population(ASMRC) and by World standard population(ASMRW) being 0.88/100,000 and 0.86/100,000, respectively. Age-specific incidence curve was bimodally distributed with age, with the first peak occurring in the second decade of the life and the second peak in the elderly. Males had higher crude and age-standardized rates for both incidence and mortality compared with females. Both crude and age-standardized incidence rates were higher in rural areas than in urban areas, so were the crude and age-standardized mortality rates.Conclusions: This population-based study presents the most recently available estimates on primary bone cancers in China, revealing that the males are 1.34 times as much as females suffering from primary bone cancers and the adolescents in puberty and the elderly are predominantly affected groups by these cancers. High-quality cancer registration data are a prerequisite for undertaking further study for gaining insight into the causes and risk factors for primary bone cancers in China.Liang Xia Rongshou Zheng Yanjun Xu Xiaojun Xu Siwei Zhang Hongmei Zeng Lifeng Lin Wanqing Chen 2019Chinese Journal of Cancer Research2019,31,1:13
8Urban expansion in China and its effect on cultivated land before and after initiating'Reform and Open Policy'显示文摘Urbanization in China has expanded at an unprecedented speed since the declaration of 'Reform and Open Policy'and presented many challenges. Unbalanced regional development, appearance of super megacities and concomitant problems,and conflicts between urbanization and cultivated land protection are three critical problems that Chinese urbanization has to face. To develop new plans for foreseeable future urbanization in China, it is critical to understand the evolving history of cities across China. This study maps urban expansion of 60 typical Chinese cities based on large amount of remote sensing data and the labor-intensive image interpretation method, in order to understand the history of urban expansion from the 1970 s to 2013.Results showed that area of cities expanded 5.23 times compared to their area in the 1970 s. Urban expansion in China accelerated three times(1988–1996, 1999–2006, and 2009–2011) and decelerated three times(1997–1998, 2007–2008, and 2012–2013) over the 40 years. The urban area of South China expanded most significantly 9.42 times, while the urban area in Northeast China expanded only 2.37 times. The disparity among different administrative ranks of cities was even greater than(3.81 times) the differences among different regions. Super megacities have been continuously expanding at a fast rate(8.60-fold), and have not shown obvious signs of slowing down. The proportion of cultivated land among the land sources for urban expansion decreased to a small extent in the 1990 s, but cultivated land continues to be the major land source for urban expansion. Effective future urbanization needs controlling the expansion scale of large cities and reasonably developing medium and small cities, as well as balancing regional development.ZHANG ZengXiang WEN QingKe LIU Fang ZHAO XiaoLi LIU Bin XU JinYong YI Ling HU ShunGuang WANG Xiao ZUO LiJun LI Na LI MinMin SHI LiFeng ZENG Tian JU HongRun 2016Science China Earth Sciences2016,59,10:12
9Effect of deformation and cooling rate on the transformation behavior and microstructure of X70 steels显示文摘The effects of the deformation in the non-recrystallization region of austenite and the cooling rate on the transformation behavior and microstructure of low-carbon low-alloy steel for pipeline application were studied on the thermal-mechanical simulator Gleeble-1500. It was shown that an increase in deformation amount can greatly increase the nucleation site of ferrite when deformed in the non-recrystallization region of austenite, and an increase in nucleation ratio can greatly refine grains. When the cooling rate is accelerated, the driving force of nucleation is increased and the nucleation rate also improves. Ultra-refine grains can be obtained by controlled rolling. The high density of ferrite nucleus, which forms along the austenite grain boundary, twin interface, and deforma- tion band are introduced in the matrix of austenite by the control of hot rolling, after which the microstructure can be refined. It was found that the acicular ferrite has a very fine sub-structure, high dislocation density, and a thin slab with ultra-fine grains. Small M/A islands and cementite are precipitated on the matrix of the slabs by the analysis technique of TEM and SEM.Zhiping Zhao Zhenmin Wang Hongmei Zhang Lifeng Qiaol 2007Journal of University of Science and Technology Beijing2007,14,5:11
10Grey matter volume abnormalities in patients with bipolar I depressive disorder and unipolar depressive disorder:a voxelbased morphometry study显示文摘Bipolar disorder and unipolar depressive disorder(UD) may be different in brain structure. In the present study,we performed voxel-based morphometry(VBM) to quantify the grey matter volumes in 23 patients with bipolar I depressive disorder(BP1) and 23 patients with UD,and 23 age-,gender-,and educationmatched healthy controls(HCs) using magnetic resonance imaging. We found that compared with the HC and UD groups,the BP1 group showed reduced grey matter volumes in the right inferior frontal gyrus and middle cingulate gyrus,while the UD group showed reduced volume in the right inferior frontal gyrus compared to HCs. In addition,correlation analyses revealed that the grey matter volumes of these regions were negatively correlated with the Hamilton depression rating scores. Taken together,the results of our study suggest that decreased grey matter volume of the right inferior frontal gyrus is a common abnormality in BP1 and UD,and decreasedgrey matter volume in the right middle cingulate gyrus may be specifi c to BP1.Yi Cai Jun Liu Li Zhang Mei Liao Yan Zhang Lifeng Wang Hongjun Peng Zhong He Zexuan Li Weihui Li Shaojia Lu Yuqiang Ding Lingjiang Li 2015Neuroscience Bulletin2015,31,1:11
11Numerical simulation on inclusion transport in continuous casting mold显示文摘Turbulent flow, the transport of inclusions and bubbles, and inclusion removal by fluid flow transport and by bubble flota- tion in the strand of the continuous slab caster are investigated using computational models, and validated through comparison with plant measurements of inclusions. Steady 3-D flow of steel in the liquid pool in the mold and upper strand is simulated with a fi- nite-difference computational model using the standard k-ε turbulence model. Trajectories of inclusions and bubbles are calculated by integrating each local velocity, considering its drag and buoyancy forces. A “random walk” model is used to incorporate the effect of turbulent fluctuations on the particle motion. The attachment probability of inclusions on a bubble surface is investigated based on fundamental fluid flow simulations, incorporating the turbulent inclusion trajectory and sliding time of each individual inclusion along the bubble surface as a function of particle and bubble size. The change in inclusion distribution due to removal by bubble transport in the mold is calculated based on the computed attachment probability of inclusions on each bubble and the computed path length of the bubbles. The results indicate that 6%-10% inclusions are removed by fluid flow transport, 10% by bubble flotation, and 4% by entrapment to the submerged entry nozzle (SEN) walls. Smaller bubbles and larger inclusions have larger attachment prob- abilities. Smaller bubbles are more efficient for inclusion removal by bubble flotation, so long as they are not entrapped in the solidi- fying shell. A larger gas flow rate favors inclusion removal by bubble flotation. The optimum bubble size should be 2-4 mm.Lifeng Zhang Brian G Thomas 2006Journal of University of Science and Technology Beijing2006,13,4:10
12The approach to calculate the aerodynamic drag of maglev train in the evacuated tube显示文摘In order to study the relationships between the aerodynamic drag of maglev and other factors in the evacuated tube,the formula of aerodynamic drag was deduced based on the basic equations of aerodynamics and then the calculated result was confirmed at a low speed on an experimental system developed by Superconductivity and New Energy R&D Center of South Jiaotong University.With regard to this system a high temperature superconducting magnetic levitation vehicle was motivated by a linear induction motor(LIM) fixed on the permanent magnetic guideway.When the vehicle reached an expected speed,the LIM was stopped.Then the damped speed was recorded and used to calculate the experimental drag.The two results show the approximately same relationship between the aerodynamic drag on the maglev and the other factors such as the pressure in the tube,the velocity of the maglev and the blockage ratio.Thus,the pressure,the velocity,and the blockage ratio are viewed as the three important factors that contribute to the energy loss in the evacuated tube transportation.Jiaqing Ma Dajing Zhou Lifeng Zhao Yong Zhang Yong Zhao 2013Journal of Modern Transportation2013,21,3:10
13Debris Flow Hazard Assessment Based on Support Vector Machine显示文摘Seven factors, including the maximum volume of once flow , occurrence frequency of debris flow , watershed area , main channel length , watershed relative height difference , valley incision density and the length ratio of sediment supplement are chosen as evaluation factors of debris flow hazard degree. Using support vector machine (SVM) theory, we selected 259 basic data of 37 debris flow channels in Yunnan Province as learning samples in this study. We create a debris flow hazard assessment model based on SVM. The model was validated though instance applications and showed encouraging results.YUAN Lifeng 1, 2 , ZHANG Youshui 3 1. Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, Sichuan, China 2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China 3. Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2006Wuhan University Journal of Natural Sciences2006,11,4:9
14Effect of extrusion speed on microstructure and mechanical properties of the Mg-Ca binary alloy显示文摘This work reported the effect of extrusion speeds on the microstructures and mechanical properties of Mg-Ca binary alloy.The results showed that yield strength of the as-extruded Mg-1.2wt.%Ca alloys decrease from∼360MPa to∼258MPa as the ram speed increases from 0.4mm/s to 2.4 mm/s,and the elongation increases from∼3.9%to∼12.2%.The microstructure changes from bimodal grain feature to the complete dynamical recrystallization(DRX)with increase of the extrusion speed.The ultrafine DRXed grains in size of∼0.85μm,the numerous nano-Mg_(2)Ca particles dispersing along the grain boundaries and interiors,as well as the high density of residual dislocations,should account for the high strength.It is believed that the high degree of dynamic recrystallization and the resulting texture randomization play the critical roles in the ductility enhancement of the high-speed extruded Mg alloys.Jingren Li Aiyue Zhang Hucheng Pan Yuping Ren Zhuoran Zeng Qiuyan Huang Changlin Yang Lifeng Ma Gaowu Qin 2021Journal of Magnesium and Alloys2021,9,4:9
15Wheat genomic study for genetic improvement of traits in China显示文摘Bread wheat(Triticum aestivum L.)is a major crop that feeds 40%of the world’s population.Over the past several decades,advances in genomics have led to tremendous achievements in understanding the origin and domestication of wheat,and the genetic basis of agronomically important traits,which promote the breeding of elite varieties.In this review,we focus on progress that has been made in genomic research and genetic improvement of traits such as grain yield,end-use traits,flowering regulation,nutrient use efficiency,and biotic and abiotic stress responses,and various breeding strategies that contributed mainly by Chinese scientists.Functional genomic research in wheat is entering a new era with the availability of multiple reference wheat genome assemblies and the development of cutting-edge technologies such as precise genome editing tools,highthroughput phenotyping platforms,sequencing-based cloning strategies,high-efficiency genetic transformation systems,and speed-breeding facilities.These insights will further extend our understanding of the molecular mechanisms and regulatory networks underlying agronomic traits and facilitate the breeding process,ultimately contributing to more sustainable agriculture in China and throughout the world.Jun Xiao Bao Liu Yingyin Yao Zifeng Guo Haiyan Jia Lingrang Kong Aimin Zhang Wujun Ma Zhongfu Ni Shengbao Xu Fei Lu Yuannian Jiao Wuyun Yang Xuelei Lin Silong Sun Zefu Lu Lifeng Gao Guangyao Zhao Shuanghe Cao Qian Chen Kunpu Zhang Mengcheng Wang Meng Wang Zhaorong Hu Weilong Guo Guoqiang Li Xin Ma Junming Li Fangpu Han Xiangdong Fu Zhengqiang Ma Daowen Wang Xueyong Zhang Hong-Qing Ling Guangmin Xia Yiping Tong Zhiyong Liu Zhonghu He Jizeng Jia Kang Chong 2022Science China(Life Sciences)2022,65,9:9
16MiR-181a-5p regulates 3T3-L1 cell adipogenesis by targeting Smad7 and Tcf7I2显示文摘Dan Ouyang Lifeng Xu Lihua zhang Dongguang Guo Xiaotong Tan Xiaofang Yu Junjie Qi Yaqiong Ye Qihong Liu Yongjiang Ma Yugu Li 2016Acta Biochimica et Biophysica Sinica2016,48,11:9
17Effect of China's rapid development on its iconic giant panda显示文摘Anthropogenic factors affect biodiversity and have led to the contraction or extinction of animal populations worldwide.Here,we use historical demographic data,spanning the past 300 years,to show that a rapid distributional contraction of giant pandas took place during the 18th and 19th centuries alongside the increase in human population.Land-use also underwent a significant change across the areas where giant pandas were found because of government agricultural policy and the introduction of new crops.The impact of social development on giant pandas includes habitat loss and fragmentation,and range reductions.Our findings would facilitate the design of effective conservation strategies that seek to conserve and increase current habitats of this iconic species,especially in areas that our analysis has identified as places where pandas have suffered from high human pressure.ZHU LiFeng HU YiBo ZHANG ZeJun WEI FuWen 2013Chinese Science Bulletin2013,58,17:8
18Heterogeneous lamellar-edged Fe-Ni(OH)_(2)/Ni_(3)S_(2)nanoarray for efficient and stable seawater oxidation显示文摘Development of efficient non-precious catalysts for seawater electrolysis is of great significance but challenging due to the sluggish kinetics of oxygen evolution reaction(OER)and the impairment of chlorine electrochemistry at anode.Herein,we report a heterostructure of Ni_(3)S_(2)nanoarray with secondary Fe-Ni(OH)_(2)lamellar edges that exposes abundant active sites towards seawater oxidation.The resultant Fe-Ni(OH)_(2)/Ni_(3)S_(2)nanoarray works directly as a free-standing anodic electrode in alkaline artificial seawater.It only requires an overpotential of 269 mV to afford a current density of 10 mA·cm^(-2)and the Tafel slope is as low as 46 m V·dec^(-1).The 27-hour chronopotentiometry operated at high current density of 100 mA·cm^(-2)shows negligible deterioration,suggesting good stability of the Fe-Ni(OH)_(2)/Ni_(3)S_(2)@NF electrode.Faraday efficiency for oxygen evolution is up to〜95%,revealing decent selectivity of the catalyst in saline water.Such desirable catalytic performance could be benefitted from the introduction of Fe activator and the heterostructure that offers massive active and selective sites.The density functional theory(DFT)calculations indicate that the OER has lower theoretical overpotential than Cl_(2) evolution reaction in Fe sites,which is contrary to that of Ni sites.The experimental and theoretical study provides a strong support for the rational design of high-performance Fe-based electrodes for industrial seawater electrolysis.Baihua Cui Zheng Hu Chang Liu Siliang Liu Fangshuai Chen Shi Hu Jinfeng Zhang Wei Zhou Yida Deng Zhenbo Qin Zhong Wu Yanan Chen Lifeng Cui Wenbin Hu 2021Nano Research2021,14,4:7
19Microphysical Characteristics of Precipitation during Pre-monsoon,Monsoon, and Post-monsoon Periods over the South China Sea显示文摘Raindrop size distribution (RSD) characteristics over the South China Sea (SCS) are examined with onboard Parsivel disdrometer measurements collected during marine surveys from 2012 to 2016. The observed rainfall is divided into premonsoon, monsoon, and post-monsoon periods based on the different large-scale circumstances. In addition to disdrometer data, sounding observation, FY-2E satellite, SPRINTARS (Spectral Radiation-Transport Model for Aerosol Species), and NCEP reanalysis datasets are used to illustrate the dynamical and microphysical characteristics associated with the rainfall in different periods. Significant variations have been observed in respect of raindrops among the three periods. Intercomparison reveals that small drops (D < 1 mm) are prevalent during pre-monsoon precipitation, whereas medium drops (1?3 mm) are predominant in monsoon precipitation. Overall, the post-monsoon precipitation is characterized by the least concentration of raindrops among the three periods. But, several large raindrops could also occur due to severe convective precipitation events in this period. Classification of the precipitation into stratiform and convective regimes shows that the lg(Nw) value of convective rainfall is the largest (smallest) in the pre-monsoon (post-monsoon) period, whereas the Dm value is the smallest (largest) in the pre-monsoon (post-monsoon) period. An inversion relationship between the coefficient A and the exponential b of the Z?R relationships for precipitation during the three periods is found. Empirical relations between Dm and the radar reflectivity factors at Ku and Ka bands are also derived to improve the rainfall retrieval algorithms over the SCS. Furthermore, the possible causative mechanisms for the significant RSD variability in different periods are also discussed with respect to warm and cold rain processes, raindrop evaporation, convective activities, and other meteorological factors.Qingwei ZENG Yun ZHANG Hengchi LEI Yanqiong XIE Taichang GAO Lifeng ZHANG Chunming WANG Yanbin HUANG 2019Advances in Atmospheric Sciences2019,36,10:7
20Laser direct writing and characterizations of flexible piezoresistive sensors with microstructures显示文摘Functional materials with high viscosity and solid materials have received more and more attentions in flexible pressure sensors,which are inadequate in the most used molding method.Herein,laser direct writing(LDW)method is proposed to fabricate flexible piezoresistive sensors with microstructures on PDMS/MWCNTs composites with an 8%MWCNTs mass fraction.By controlling laser energy,microstructures with different geometries can be obtained,which significantly impacts the performances of the sensors.Subsequently,curved microcones with excellent performance are fabricated under parameters of f=40 kHz and v=150 mm·s^(-1).The sensor exhibits continuous multi-linear sensitivity,ultrahigh original sensitivity of 21.80%kPa^(-1),wide detection range of over 20 kPa,response/recovery time of~100 ms and good cycle stability for more than 1000 times.Besides,obvious resistance variation can be observed when tiny pressure(a peanut of 30 Pa)is applied.Finally,the flexible piezoresistive sensor can be applied for LED brightness controlling,pulse detection and voice recognition.Chenying Zhang Wei Zhou Da Geng Cheng Bai Weida Li Songyue Chen Tao Luo Lifeng Qin Yu Xie 2021Opto-Electronic Advances2021,4,4:7
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