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132篇 您的检索式:作者名="Zhenguo Wang"
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1Mapping wetland changes in China between 1978 and 2008显示文摘Four wetland maps for all China have been produced,based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978,1990,2000 and 2008).These maps were mainly developed by manual interpretation and validated by substantial field investigation in 2009.Based on these maps,we analyzed the 2008 wetland distribution in China and discussed wetland changes and their drivers over the past 30 years.(i) There were about 324097 km 2 of wetlands in 2008,for which inland marshes or swamps were the most common wetland type (35%),with lakes (26%) second.Most of the wetlands were in Heilongjiang,Inner Mongolia,Qinghai and Tibet,occupying about 55% of the national wetland area.(ii) From 1978 to 2008,China's wetland area continually and significantly decreased,by about 33% based on changes in the wetland map.This was in sharp contrast to the increase in artificial wetlands,which increased by about 122%.Inland marshes accounted for the main loss of total wetlands from 1978 to 2000.From 2000 through 2008,riverine and lacustrine wetlands constituted the main wetland loss.Fortunately however,the rate of wetland loss decreased from 5523 to 831 km 2 /a.(iii) The change ratio of lost natural wetlands (including inland and coastal wetlands) to non-wetlands has decreased slightly over the past 30 years.From 1978 to 1990,nearly all natural wetlands (98%) lost were transformed into non-wetlands.However,the ratio declined to 86% from 1990 to 2000,and to 77% from 2000 to 2008.(iv) All Chinese provinces were divided into three groups according to patterns of wetland changes,which could relate to the driving forces of such changes.Tibet was completely different from other provinces,as it was one representative example in which there was a net wetland increase,because of global warming and decreased human activity since 1990.Increased economic development caused considerable wetland loss in most eastern provinces,and artificial wetlands increased.NIU ZhenGuo ZHANG HaiYing WANG XianWei YAO WenBo ZHOU DeMin ZHAO KuiYi ZHAO Hui LI NaNa HUANG HuaBing LI CongCong YANG Jun LIU CaiXia LIU Shuang WANG Lin LI Zhan YANG ZhenZhong QIAO Fei ZHENG YaoMin CHEN YanLei SHENG YongWei GAO XiaoHong ZHU WeiHong WANG WenQing WANG Hong WENG YongLing ZHUANG DaFang LIU JiYuan LUO ZhiCai CHENG Xiao GUO ZiQi GONG Peng 2012Chinese Science Bulletin2012,57,22:51
2China's wetland change (1990-2000) determined by remote sensing显示文摘Two wetland maps for the entire China have been produced based on Landsat data acquired around 1990 and 2000. Wetlands in China have been divided into 3 broad categories with 15 sub-categories except rice fields. In 1990, the total wetland area in China was 355208 km2 whereas in 2000 it dropped to 304849 km2 with a net loss of 50360 km2. During an approximate 10-year period, inland wetland reduced from 318326 to 257922 km2, coastal wetland dropped from 14335 to 12015 km2, while artificial wetland increased from 22546 to 34911 km2. The greatest natural wetland loss occurred in Heilongjiang, Inner Mon- golia, and Jilin with a total loss of over 57000 km2 of wetland. In western China, over 13000 km2 of wetlands were newly formed in Xinjiang, Tibet, and Qinghai. About 12000 km2 of artificial wetlands were also added for fish farm and reservoir constructions. The newly formed wetlands in western China were caused primarily by climate warming over that region whereas the newly created artificial wetlands were caused by economic developments. China’s wetland loss is caused mainly by human activities.Peng Gong ZhenGuo Niu Xiao Cheng KuiYi Zhao DeMin Zhou JianHong Guo Lu Liang XiaoFeng Wang DanDan Li HuaBing Huang et al. 2010Science China Earth Sciences2010,53,7:28
3Suppression of Jasmonic Acid-Mediated Defense by Viral-Inducible MicroRNA319 Facilitates Virus Infection in Rice显示文摘MicroRNAs (miRNAs ) 是植物开发和主人病毒相互作用的枢轴的调节的人。然而,角色和涉及病毒的感染和主人危险性的特定的 miRNAs 的行动模式仍然保持大部分不清楚。在这研究,我们给那瑞斯看引起 miR319 的增加的累积,但是减少的破旧绝技病毒(RRSV ) 感染调整 miR319 的 TCP (TEOSINTE BRANCHED/CYCLOIDEA/PCF ) 的表示基因,特别 TCP21,在米饭植物。转基因的米饭植物 overexpressing miR319 或 downregulating TCP21 展出了像疾病的显型并且与野类型的植物比较显示出显著地更高的危险性到 RRSV。相反,仅仅温和的疾病症状在感染 RRSV 的线 overexpressing TCP21 并且特别在转基因的植物 overexpressing 被观察 miR319 抵抗的 TCP21。miR319 的 RRSV 感染和 overexpression 在米饭与 JA 生合成和信号相关的基因的 downregulated 表示一起引起了减少的内长的 jasmonic 酸(JA ) 层次。然而,有甲基 jasmonate 的米饭植物的治疗减轻了 RRSV 引起并且减少了病毒累积的疾病症状。一起拿,我们的结果建议由在米饭的 RRSV 感染的 miR319 的正式就职压制调停 JA 的防卫便于病毒感染和症状开发。Chao Zhang Zuomei Ding Kangcheng Wu Liang Yang Yang Li Zhen Yang Shan Shi Xiaojuan Liu Shanshan Zhao Zhirui Yang Yu Wang Luping Zheng Juan Wei Zhenguo Du Aihong Zhang Hongqin Miao Yi Li Zujian Wu Jianguo Wu 2016Molecular Plant2016,9,9:27
4The recommendations of Chinese Parkinson’s disease and movement disorder society consensus on therapeutic management of Parkinson’s disease显示文摘Background:Parkinson’s disease(PD)is a chronic,progressive and debilitating disease,which affects over 2.5 million people in China.PD is characterized clinically by resting tremor,muscular rigidity,bradykinesia and postural instability.As the disease progresses,additional complications can arise such as non-motor and neurobehavioral symptoms.Pharmacological treatment and surgical intervention for PD have been implemented in China.Until 10 years ago,there was lack of standardization for the management of PD in different regions and among different physicians,leading to different treatment levels in different regions and different physicians.Since then,the Chinese Parkinson’s Disease and Movement Disorder Society have published three versions of guidelines for the management of PD in China,in 2006,2009 and 2014,respectively.Correspondingly,the overall level of treatment for PD in China improved.Objectives:To update the treatment guidelines based on current foreign and domestic practice guidelines and clinical evidence,and to improve the treatment options available to physicians in the management of PD.Summary:A variety of treatment recommendations in the treatment guidelines have been proposed,including physical activity and disease-modifying medication,which should be initiated at the early-stage of the disease.The principles of dosage titration should be followed to avoid acute adverse reactions to the drugs,to achieve a satisfactory clinical effect with a low dose and to reduce the incidence of long-term motor complications.Moreover,different treatment strategies should be considered at different stages of the disease.Importantly,treatment guidelines and personalized treatments should be valued equally.A set of treatment recommendations has been developed to assist physicians to improve and optimize clinical outcomes for patients with PD in China.Shengdi Chen Piu Chan Shenggang Sun Haibo Chen Baorong Zhang Weidong Le Chunfeng Liu Guoguang Peng Beisha Tang Lijuan Wang Yan Cheng Ming Shao Zhenguo Liu Zhenfu Wang Xiaochun Chen Mingwei Wang Xinhua Wan Huifang Shang Yiming Liu Pingyi Xu Jian Wang Tao Feng Xianwen Chen Xingyue Hu Anmu Xie Qin Xiao 2016Translational Neurodegeneration2016,5,1:23
5Investigation on high angle of attack characteristics of hypersonic space vehicle显示文摘The high angle of attack characteristics play an important role in the aerodynamic performances of the hypersonic space vehicle. The three-dimensional Reynolds Averaged Navier-Stokes (RANS) equations and the two-equation RNG k-? turbulence model have been employed to investigate the influence of the high angle of attack on the lift-to-drag ratio and the flow field characteristics of the hypersonic space vehicle, and the contributions of each component to the aerodynamic forces of the vehicle have been discussed as well. At the same time, in order to validate the numerical method, the predicted results have been compared with the available experimental data of a hypersonic slender vehicle, and the grid independency has been analyzed. The obtained results show that the predicted lift-to-drag ratio and pitching moment coefficient show very good agreement with the experimental data in the open literature, and the grid system makes only a slight difference to the numerical results. There exists an optimal angle of attack for the aerodynamic performance of the hypersonic space vehicle, and its value is 20°. When the angle of attack is 20°, the high pressure does not leak from around the leading edge to the upper surface. With the further increasing of the angle of attack, the high pressure spreads from the wing tips to the central area of the vehicle, and overflows from the leading edge again. Further, the head plays an important role in the drag performance of the vehicle, and the lift percentage of the flaperon is larger than that of the rudderevator. This illustrates that the optimization of the flaperon configuration is a great work for the improvement of the aerodynamic performance of the hypersonic space vehicle, especially for a high lift-to-drag ratio.HUANG Wei LI ShiBin LIU Jun WANG ZhenGuo 2012Science China(Technological Sciences)2012,55,5:19
6Design and aerodynamic investigation of a parallel vehicle on a wide-speed range显示文摘In order to design a hypersonic vehicle for a wide-ranged Mach number,a novel parallel vehicle for a wide-speed range has been proposed.In this paper,we employ a numerical method to investigate a parallel vehicle’s aerodynamic performance and flow field characteristics.The obtained results show that the aerodynamic performance of the novel parallel vehicle is better than that of the waverider designed with a single Mach number for the wide-speed range.With the increase in Mach number,the lift-to-drag ratio of the novel parallel vehicle first increases and then decreases.When the Mach number is 7 and the angle of attack is 3?,the lift-to-drag ratio is the largest,and its value is 3.968.When the angle of attack is 3?,the lift-to-drag ratio is not lower than 3.786 in the range considered in the current study,and the novel parallel vehicle’s aerodynamic performance is good.The wing changes the drag performance of the parallel vehicle remarkably,and results in the decrease of the lift-to-drag ratio.Meanwhile,the wing can enhance the pitching moment performance.LI ShiBin HUANG Wei WANG ZhenGuo LEI Jing 2014Science China(Information Sciences)2014,57,12:16
7Recent Developments in the Crystallization Process: Toward the Pharmaceutical Industry显示文摘Zhenguo Gao Sohrab Rohani Junbo Gong Jingkang Wang 2017Engineering2017,3,3:16
8Geographical characteristics of China’s wetlands derived from remotely sensed data显示文摘In this paper, we report the first wetland mapping of the entire China using Landsat enhanced thematic mapper plus (ETM+) data. These data were obtained from the Global Land Cover Facility at the University of Maryland spanning from 1999 to 2002. A total of 597 scenes of Landsat images were georeferenced and mosaiced. Manual image interpretation of satellite images was aided with elevation data, soil data, land cover/land use data and Google Earth. The minimum mapping unit is 10 pixel × 10 pixel, equivalent to 9 ha. The aim of our first round of mapping was only targeted at the boundary delineation of any type of wetland except those wetlands that are under agricultural use (i.e., paddy fields), which has already been well mapped by others. Our interpretation results indicate that a total of 359478 km2 of wetlands are of non-agricultural use. Among our preliminarily mapped wetland, 339353 km2 are inland wetland, 2786 km2 are non-agricultural artificial wetland, and 17609 km2 are coastal wetland. Because low-tide is rarely captured in satellite images, an under-estimation of coastal wetland is inevitable. We conducted some statistics based on our mapped wetlands and compared them with those previously obtained from a number of sources including a land cover/land use map made with satellite images during the late 1990s and early 2000s, a marshland map developed in approximately the same period, survey data of coastal wetland in early 1980s, and area data for approximately 400 larger patches of marshland in China compiled in 1996. Because some inconsistencies exist in the guidelines of those different wetland surveys, difference in area is expected. Some further comparison indicates that the wetland distributions derived from the preliminary wetland map are reasonable and more objective than other sources. The mapping process also indicated that the method adopted by us was efficient and cost-effective. We also found that in order to ensure comparability of the wetland maps developed at different times, a set of standard guidelines on the wetland categories to be mapped, and the mapping methods to be used must be well conceived, developed and effectively employed. We carried out some initial geographical analysis on the distribution of wetlands.NIU ZhenGuo GONG Peng CHENG Xiao GUO JianHong WANG Lin HUANG HuaBing SHEN ShaoQing WU YunZhao WANG XiaoFeng WANG XianWei YING Qing LIANG Lu ZHANG LiNa WANG Lei YAO Qian YANG ZhenZhong GUO ZiQi DAI YongJiu 2009Science China Earth Sciences2009,52,6:15
9Clinical characteristics of human infection with a novel avian-origin influenza A(H10N8) virus显示文摘Zhang Wei Wan Jianguo Qian Kejian Liu Xiaoqing Xiao Zuke Sun Jian Zeng Zhenguo Wang Qi Zhang Jinxiang Jiang Guanghui Nie Cheng Jiang Rong Ding Chengzhi Li Ran Horby Peter Gao Zhancheng 2014Chinese Medical Journal2014,,18:12
10Effect of Panax notoginseng saponins on the expression of beta-amyloid protein in the cortex of the parietal lobe and hippocampus, and spatial learning and memory in a mouse model of senile dementia显示文摘BACKGROUND: The pharmacological actions of Panax notoginseng saponins (PNS) lie in removing free radicals, anti-inflammation and anti-oxygenation. It can also improve memory and behavior in rat models of Alzheimer’s disease. OBJECTIVE: Using the Morris water maze, immunohistochemistry, real-time PCR and RT-PCR, this study aimed to measure improvement in spatial learning, memory, expression of amyloid precursor protein (App) and β-amyloid (Aβ), to investigate the mechanism of action of PNS in the treatment of AD in the senescence accelerated mouse-prone 8 (SAMP8) and compare the effects with huperzine A. DESIGN, TIME AND SETTING: A completely randomized grouping design, controlled animal experiment was performed in the Center for Research & Development of New Drugs, Guangxi Traditional Chinese Medical University from July 2005 to April 2007. MATERIALS: Sixty male SAMP8 mice, aged 3 months, purchased from Tianjin Chinese Traditional Medical University of China, were divided into four groups: PNS high-dosage group, PNS low-dosage group, huperzine A group and control group. PNS was provided by Weihe Pharmaceutical Co., Ltd. (batch No.: Z53021485, Yuxi, Yunan Province, China). Huperzine A was provided by Zhenyuan Pharmaceutical Co., Ltd. (batch No.: 20040801, Zhejiang, China). METHODS: The high-dosage group and low-dosage group were treated with 93.50 and 23.38 mg/kg PNS respectively per day and the huperzine A group was treated with 0.038 6 mg/kg huperzine A per day, all by intragastric administration, for 8 consecutive weeks. The same volume of double distilled water was given to the control group. MAIN OUTCOME MEASURES: After drug administration, learning and memory abilities were assessed by place navigation and spatial probe tests. The recording indices consisted of escape latency (time-to-platform), and the percentage of swimming time spent in each quadrant. The number of Aβ1-40, Aβ1-42 and App immunopositive neurons in the brains of SAMP8 mice was analyzed by immunohistochemistry. The mRNA content of App, tau, acetylcholinesterase, and synaptophysin (Syp) was tested by real time PCR and RT-PCR. RESULTS: The PCR results show that PNS can downregulate the expression of the App gene and upregulate the expression of the Syp gene in the parietal cortex and hippocampus of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than those of the PNS low-dosage group and the huperzine A group (P < 0.05). The results of the Morris water maze and immunohistochemistry indicated that PNS can improve the capacity for spatial learning and memory in SAMP8 mice, and reduce the content of Aβ1-40, Aβ1-42 and expression of App in the brains of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than that of the PNS low-dosage group and the huperzine A group (P < 0.05). CONCLUSION: These results support the hypothesis that PNS plays a therapeutic and protective role on the pathological lesions and learning dysfunction of Alzheimer’s disease. The therapeutic effects of PNS for Alzheimer’s disease are possibly achieved through downregulating the expression of the App gene and upregulating the expression of the Syp gene. The therapeutic effects of PNS are dose-dependent and are greater than the effect of huperzine A.Zhenguo Zhong Dengpan Wu Liang Lu Jinsheng Wang Wenyan Zhang Zeqiang Qu 2008Neural Regeneration Research2008,3,12:9
11Research status of key techniques for shock-induced combustion ramjet(shcramjet) engine显示文摘As one of the most promising propulsion systems in the future,shock-induced combustion ramjet engine can remedy the disadvantages in the integrated design of scramjet engine and airframe.It can shorten the length of the combustor,lighten the structure weight of the engine and keep better performance in a broad range of flight Mach number.The elementary principle of shock-induced combustion ramjet engine is introduced.The key technologies of this kind of propulsion system are described,while their research status is presented in detail.Suggestion on the development of shcramjet engine in China is put forward.HUANG Wei,QIN Hui,LUO ShiBin & WANG ZhenGuo Institute of Aerospace & Materials Engineering,National University of Defense Technology,Changsha 410073,China 2010Science China(Technological Sciences)2010,53,1:9
12Design and analysis of a hypersonic inlet with an integrated bump/forebody显示文摘Numerical simulations and experiments showed that bump inlet had a remarkable effect on boundary layer diversion of supersonic flow.However,the design and analysis of bump in hypersonic flow was still few.In this paper,the mechanism of a supersonic bump inlet is introduced to the design of hypersonic forebody.A hypersonic inlet with an integrated bump/forebody is obtained by the Method Of Characteristics(MOC)based on a chin inlet.Numerical simulations show that the modified inlet achieves diversion of low-speed flow.Besides,the integrated bump/-forebody is also beneficial to inlet start.During the starting process,the shape of the separation zone is rebuilt by the modified forebody surface which makes spillage much easier.This new design leads to a reduction of the self-start Mach number by 0.95.Shangcheng XU Yi WANG Zhenguo WANG Xiaoqiang FAN Xingyu ZHAO 2019Chinese Journal of Aeronautics2019,32,10:9
13Multidisciplinary design optimization approach and its application to aerospace engineering显示文摘The multidisciplinary design optimization(MDO)approach is very crucial for the conceptual design of the aircraft,and this is due to the complex interaction between different disciplines, especially for the hypersonic vehicle. In the hypersonic vehicle, the airframe and the engine are highly integrated. In the current survey, the research progress in the MDO approach has been reviewed comprehensively from four primary techniques, namely the design of experiments, the surrogate modeling, the optimization method and the MDO framework, and its application to the aerospace engineering has been summarized from its category as well. The concurrent subspace optimization approach is the most popular method in the aerospace engineering for its easy implementation, and following is the collaborative optimization approach. The multi-level optimization approach has attracted a growing attention due to its high efficiency. In conclusion, some promising research recommendations have been put forward, namely the combination of the low- and high-fidelity optimization approaches, the consideration of the uncertainty analysis and the MDO approach coupled with the data mining techniques.Zhenguo Wang Wei Huang Li Yan 2014Chinese Science Bulletin2014,59,36:7
14Theoretical analysis of flamelet model for supersonic turbulent combustion显示文摘Being physically intuitionistic and computationally efficient,the flamelet model has obtained increasing attention and becomes popular in numerical simulations of supersonic combustion.However,the flamelet model was firstly built for simulations of the low-speed flows.Therefore it is still unclear whether the assumption of the flamelet model is reasonable in supersonic combustion.This paper tries to identify the existence of the flamelet mode in supersonic combustion.Firstly,the interaction of the turbulent fluctuation and the flame is discussed,based on which the combustion regime is distinguished.Then the charac-teristic length scale of the turbulent flows and the combustion inside the scramjet combustor are calculated and compared,which are used to identify whether the assumption of the flamelet model is reasonable in supersonic flows.The results show that for premixed combustion,due to the low fluctuation velocity in the recirculation zone and the shear layer,the assumption of the flamelet model is established for all the flight Mach numbers,while for non-premixed combustion the assumption is also established for most of the flight Mach numbers except for very high Mach number under which the slow reaction mode dominates the combustion.In order to quantitatively examine the combustion mode,numerical calculations are performed to simulate the strut-injection supersonic combustion which has been experimentally investigated in German Aerospace Center.The results show that the supersonic combustion occurs in the fully-developed turbulent regions and the assumption of the flamelet model is established in the whole flow field.FAN ZhouQin LIU WeuDong SUN MingBo WANG ZhenGuo ZHUANG FengChen LUO WenLei 2012Science China(Technological Sciences)2012,55,1:7
15Experimental Study on Effects of Fuel Injection on Scramjet Combustor Performance显示文摘In order to investigate the effects of fuel injection distribution on the scramjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combus- tor performances. In addition, an inner-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances.Wu Xianyu Li Xiaoshan Ding Meng Liu Weidong Wang Zhenguo 2007Chinese Journal of Aeronautics2007,20,6:7
16Super-Tough and Environmentally Stable Aramid Nanofiber@MXene Coaxial Fibers with Outstanding Electromagnetic Interference Shielding Efficiency显示文摘Although electrically conductive and hydrophilic MXene sheets are promising for multifunctional fibers and electronic textiles,it is still a challenge to simultaneously enhance both conductivity and mechanical properties of MXene fibers because of the high rigidity of MXene sheets and insufficient inter-sheet interactions.Herein,we demonstrate a core-shell wet-spinning methodology for fabricating highly conductive,super-tough,ultra-strong,and environmentally stable Ti_(3)C_(2)T_(x) MXene-based core-shell fibers with conductive MXene cores and tough aramid nanofiber(ANF)shells.The highly orientated and low-defect structure endows the ANF@MXene core-shell fiber with supertoughness of~48.1 MJ m^(-3),high strength of~502.9 MPa,and high conductivity of~3.0×10^(5)S m^(-1).The super-tough and conductive ANF@MXene fibers can be woven into textiles,exhibiting an excellent electromagnetic interference(EMI)shielding efficiency of 83.4 dB at a small thickness of 213μm.Importantly,the protection of the ANF shells provides the fibers with satisfactory cyclic stability under dynamic stretching and bending,and excellent resistance to acid,alkali,seawater,cryogenic and high temperatures,and fire.The oxidation resistance of the fibers is demonstrated by their wellmaintained EMI shielding performances.The multifunctional core-shell fibers would be highly promising in the fields of EMI shielding textiles,wearable electronics and aerospace.Liu-Xin Liu Wei Chen Hao-Bin Zhang Lvxuan Ye Zhenguo Wang Yu Zhang Peng Min Zhong-Zhen Yu 2022Nano-Micro Letters2022,14,7:6
17A hybrid LES (Large Eddy Simulation)/assumed sub-grid PDF (Probability Density Function) model for supersonic turbulent combustion显示文摘A hybrid LES (Large Eddy Simulation)/assumed sub-grid PDF (Probability Density Function) closure model has been devel-oped for supersonic turbulent combustion. Scalar transport equations for all species in a given chemical kinetic mechanism were solved, which are necessary in the supersonic combustion where the non-equilibrium chemistry is essentially involved. The clipped Gaussian PDF of temperature and multivariate ? PDF of composition were used to close the sub-grid chemical sources that appear in the conservation equations. The sub-grid variances of temperature and composition were constructed based on scale similarity approach. A semi-implicit approach based on the PDF model was proposed to tackle the resulting numerical stiffness associated with finite rate chemistry. The model was applied to simulate a supersonic, coaxial H2-air burner, where both the mean and rms (root mean square) results were compared with the experimental data. In general, good agree-ments were achieved, which indicated that the present sub-grid PDF method could work well in simulating supersonic turbu-lent combustion. Moreover, the calculation showed that the sub-grid fluctuations of temperature and major species in the combustion region were of the order of 10%-20% of their rms, while the sub-grid fluctuation of hydroxyl might be as high as 40%-50% of its rms.WANG HongBo QIN Ning SUN MingBo WU HaiYan WANG ZhenGuo 2011Science China(Technological Sciences)2011,54,10:6
18The First Case of Asymptomatic Infection of COVID-19-Kashgar Prefecture, Xinjiang Uygur Autonomous Region, China, October, 2020显示文摘On October 24,2020,a 17-year-old female was detected as having an asymptomatic infection of coronavirus disease 2019(COVID-19)during a regular nucleic acid test in Kashgar Prefecture,Xinjiang Uygur Autonomous Region.She was then transferred to a local designated hospital for medical observation.The patient lived in Shufu County of Kashgar Prefecture and worked in a local garment factory.On the afternoon of October 24 after she was diagnosed as positive,a total of 831 persons in the garment factory were tested and the results were all negative.Afterwards,16 close contacts and 406 of close contacts of close contacts were also tested,and 137 were positive and had asymptomatic infections.Ji Wang Jun Zhao Xiang Zhao Zhenguo Gao Yang Song Xin Ma Kai Nie Aimin Xu Mahemuti Ling Zhang Wenbo Xu Yan Cui 2020China CDC weekly2020,2,45:6
19Effect of cavity flame holder configuration on combustion flow field performance of integrated hypersonic vehicle显示文摘As one of the most common methods to be used as the flame holding mechanism in the propulsion system of the integrated hypersonic vehicle,the research of cavity flame holder has drawn an ever increasing attention of many researchers. The two-dimensional coupled implicit NS equations,the standard k-ε turbulent models and the finite-rate/eddy-dissipation reaction model were employed to simulate the experimental items arranged by the orthogonal design,and the variance analysis method was used to investigate the effects of the geometric parameters of the cavity flame holder on the aero-propulsive performance of the integrated hypersonic vehicle,namely the depth,the ratio of length-to-depth and the sweepback angle. The obtained results show that the geometric parameters make only a little difference to the aero-propulsive performance of the vehicle in the range considered in this paper,and the cavity flame holder with its sweepback angle 45° can satisfy the performance requirement of the integrated hypersonic vehicle further. The hydrogen injected from the upper stream of the cavity makes the boundary layer separate on the lower wall of the engine,and a separate region appears in the upper stream and down stream of the injection slot,respectively.HUANG Wei, LUO ShiBin, LIU Jun & WANG ZhenGuo Institute of Aerospace & Materials Engineering, National University of Defense Technology, Changsha 410073, China 2010Science China(Technological Sciences)2010,53,10:6
20Methanogenic archaea and sulfate reducing bacteria induce severe corrosion of steel pipelines after hydrostatic testing显示文摘Complex interactions within a microbial consortium can induce severe corrosion in oil pipelines.This study investigated the mechanism of microbiologically influenced corrosion(MIC)that led to failure of X52 steel pipelines after hydrostatic testing.Laboratory hydrostatic testing with untreated lake water and underground water were used to simulate and study the events that led to the actual corrosion.Biofilm analysis,weight loss,and several electrochemical measurements demonstrated rapid corrosion rates after hydrostatic testing.Analysis of microbial community structures revealed that methanogenic archaea and sulfate reducing bacteria(SRB),introduced by the hydrotest water,formed corrosive biofilms on X52 steel coupon surfaces that induced severe pitting.Enze Zhou Jianjun Wang Masoumeh Moradi Huabing Li Dake Xu Yuntian Lou Jinheng Luo Lifeng Li Yulei Wang Zhenguo Yang Fuhui Wang Jessica A.Smith 2020Journal of Materials Science & Technology2020,47,13:5
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