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| 1 | Spatial and temporal variations and controlling factors of potential evapotranspiration in China:1956-2000显示文摘Based on the climatic data of 580 stations in China during 1956 and 2000, potential evapotranspiration are calculated using the Penman-Monteith Method recommended by FAO. The spatial and temporal distributions of the potential evapotranspiration over China and the temporal trends of the regional means for 10 major river basins and whole China are analyzed. Through a partial correlation analysis, the major climate factors which affect the temporal change of the potential evapotranspiration are analyzed. Major results are drawn as follows: 1) The seasonal and annual potential evapotranspiration for China as a whole and for most basins show decline tendencies during the past 45 years; for the Songhua River Basin there appears a slightly increasing trend. 2) Consequently, the annual potential evapotranspirations averaged over 1980-2000 are lower than those for the first water resources assessment (1956-1979) in most parts of China. Exceptions are found in some areas of Shandong Peninsula, western and middle basins of the rivers in Southwest China, Ningxia Hui Autonomous Region as well as the source regions of the Yangtze and Yellow rivers, which may have brought about disadvantages to the exploration and utilization of water resources. 3) Generally, sunshine duration, wind speed and relative humidity have greater impact on the potential evapotranspiration than temperature. Decline tendencies of sunshine duration and/or wind speed in the same period appear to be the major causes for the negative trend of the potential evapotranspiration in most areas. | GAO Ge CHEN Deliang REN Guoyu CHEN Yu LIAO Yaoming | 2006 | Journal of Geographical Sciences2006，16，1： | 34 |
| 2 | Physical and numerical investigation on transient cavitating flows显示文摘The objective of this paper is to investigate transient cavitating flows around a hydrofoil via combined physical and numerical studies. The aims are to 1) investigate the periodic formation, breakup, shedding, and collapse of the sheet/cloud cavities, 2) provide a better insight in the physical mechanism that governs the dynamics and structures of the sheet/cloud cavitation, 3) quantify the influence of cavitation on the surrounding flow structures. Results are presented for a Clark-Y hydrofoil fixed at an angle of attack of a=8° at a moderate Reynolds number, Re=7×105 , for sheet/cloud cavitating conditions. The experimental studies were conducted in a cavitation tunnel at Beijing Institute of Technology, China. The numerical simulations are performed by solving the incompressible, multiphase unsteady Reynolds-averaged Navier-Stokes (URANS) equations via the commercial code CFX using a transport equation-based cavitation model; a filter-based density corrected model (FBDCM) is used to regulate the turbulent eddy viscosity in both the cavitation regions near the foil and in the wake. The results show that numerical predictions are capable of capturing the initiation of the cavity, growth toward the trailing edge, and subsequent shedding in accordance with the quantitative features observed in the experiment. Regarding vapor shedding in the cavitating flow around the three-dimensional foil, it is primarily attributed to the effect of the re-entrant flow, which is formed due to the strong adverse pressure gradient. The results show strong correlation between the cavity and vorticity structures, demonstrating that the inception, growth, shedding, and collapse of sheet/cloud cavities are important mechanisms for vorticity production and modification. | HUANG Biao WANG GuoYu ZHAO Yu WU Qin | 2013 | Science China(Technological Sciences)2013，56，9： | 15 |
| 3 | Detached-eddy Simulation for Time-dependent Turbulent Cavitating Flows显示文摘The Reynolds-averaged Navier-Stokes(RANS),such as the original k-ω two-equation closures,have been very popular in providing good prediction for a wide variety of flows with presently available computational resource.But for cavitating flows,the above equations noticeably over-predict turbulent production and hence effective viscosity.In this paper,the detached eddy simulation(DES) method for time-dependent turbulent cavitating flows is investigated.To assess the state-of-the-art of computational capabilities,different turbulence models including the widely used RANS model and DES model are conducted.Firstly,in order to investigate the grid dependency in computations,different grid sizes are adopted in the computation.Furthermore,the credibility of DES model is supported by the unsteady cavitating flows over a 2D hydrofoil.The results show that the DES model can effectively reduce the eddy viscosities.From the experimental validations regarding the force analysis,frequency and the unsteady cavity visualizations,more favorable agreement with experimental visualizations and measurements are obtained by DES model.DES model is better able to capture unsteady phenomena including cavity length and the resulting hydrodynamic characteristics,reproduces the time-averaged velocity quantitatively around the hydrofoil,and yields more acceptable and unsteady dynamics features.The DES model has shown to be effective in improving the overall predictive capability of unsteady cavitating flows. | HUANG Biao WANG Guoyu YU Zhiyi SHI Shuguo | 2012 | Chinese Journal of Mechanical Engineering2012，25，3： | 10 |
| 4 | A cavitation model for computations of unsteady cavitating flows显示文摘A local vortical cavitation(LVC) model for the computation of unsteady cavitation is proposed.The model is derived from the Rayleigh–Plesset equations,and takes into account the relations between the cavitation bubble radius and local vortical effects.Calculations of unsteady cloud cavitating fows around a Clark-Y hydrofoil are performed to assess the predictive capability of the LVC model using well-documented experimental data.Compared with the conventional Zwart's model,better agreement is observed between the predictions of the LVC model and experimental data,including measurements of time-averaged fl w structures,instantaneous cavity shapes and the frequency of the cloud cavity shedding process.Based on the predictions of the LVC model,it is demonstrated that the evaporation process largely concentrates in the core region of the leading edge vorticity in accordance with the growth in the attached cavity,and the condensation process concentrates in the core region of the trailing edge vorticity,which corresponds to the spread of the rear component of the attached cavity.When the attached cavity breaks up and moves downstream,the condensation area fully transports to the wake region,which is in accordance with the dissipation of the detached cavity.Furthermore,using vorticity transport equations,we also fin that the periodic formation,breakup,and shedding of the sheet/cloud cavities,along with the associated baroclinic torque,are important mechanisms for vorticity production and modification When the attached cavity grows,the liquid–vapour interface that moves towards the trailing edge enhances the vorticity in the attached cav-ity closure region.As the re-entrant jet moves upstream,the wavy/bubbly cavity interface enhances the vorticity near the trailing edge.At the end of the cycle,the break-up of the stable attached cavity is the main reason for the vorticity enhancement near the suction surface. | Yu Zhao Guoyu Wang Biao Huang | 2016 | Acta Mechanica Sinica2016，32，2： | 9 |
| 5 | Multiphase fluid dynamics and transport processes of low capillary number cavitating flows显示文摘To better understand the multiphase fluiddynamics and associated transport processes of cavitatingflows at the capillary number of 0.74 and 0.54,and to validatethe numerical results,a combined computational and exper-imental investigation of flows around a hydrofoil is stud-ied based on flow visualizations and time-resolved interfacemovement.The computational model is based on a mod-ified RNG k-ε model as turbulence closure,along with avapor-liquid mass transfer model for treating the cavitationprocess.Overall,favorable agreement between the numericaland experimental results is observed.It is shown that the cavi-tation structure depends on the interaction of the water-vapormixture and the vapor among the whole cavitation stage,the interface between the vapor and the two-phase mixtureexhibits substantial unsteadiness.And,the adverse motionof the interface relates to pressure and velocity fluctuationsinside the cavity.In particular,the velocity in the vapor regionis lower than that in the two-phase region. | Xiangbin Li Guoyu Wang Zhiyi Yu Wei Shyy | 2009 | Acta Mechanica Sinica2009，25，2： | 6 |
| 6 | Study of weighted space deconvolution algorithm in computer controlled optical surfacing formation显示文摘Theoretical and experimental research on the deconvolution algorithm of dwell time in the technology of computer controlled optical surfacing (CCOS) formation is made to get an ultra-smooth surface of space optical element. Based on the Preston equation, the convolution model of CCOS is deduced. Considering the morbidity problem of deconvolution algorithm and the actual situation of CCOS technology, the weighting spatial deconvolution algorithm is presented based on the non-periodic matrix model, which avoids solving morbidity resulting from the noise induced by measurement error. The discrete convolution equation is solved using conjugate gradient iterative method and the workload of iterative calculation in spatial domain is reduced effectively. Considering the edge effect of convolution algorithm, the method adopts a marginal factor to control the edge precision and attains a good effect. The simulated processing test shows that the convergence ratio of processed surface shape error reaches 80%. This algorithm is further verified through an experiment on a numerical control bonnet polishing machine, and an ultra-smooth glass surface with the root-mean-square (RMS) error of 0.0088 μm is achieved. The simulation and experimental results indicate that this algorithm is steady, convergent, and precise, and it can satisfy the solving requirement of actual dwell time. | 李洪玉 张伟 Guoyu Yu | 2009 | Chinese Optics Letters2009，7，7： | 5 |
| 7 | Incidence and prevalence of moyamoya disease in urban China: a nationwide retrospective cohort study显示文摘Background and objective Moyamoya disease(MMD)is an increasingly recognised cause of stroke,mainly described in East Asia.China is the largest nation in Asia,but few studies reported the epidemiology of MMD,especially at a national level.We aimed to estimate the incidence and prevalence of MMD in China.Methods We performed a population-based study using data from the national databases of Urban Basic Medical Insurance between 2013 and 2016,covering approximately 0.50 billion individuals.MMD cases were identified by diagnostic code(International Classification of Diseases,10th Revision I67.5)or related diagnostic text.Results A total of 1987 MMD patients(mean age 44.45±14.30 years,female-to male ratio 1.12)were identified,representing a national crude incidence of 0.59(95%CI:0.49 to 0.68)and a prevalence of 1.01(95%CI:0.81 to 1.21)per 100000 person-years in 2016.Rates were higher in females than in males for the incidence(0.66 vs 0.52)and prevalence(1.05 vs 0.90).And the age-specific rates showed a bimodal distribution,with the highest peak in middle-aged group and the second peak in child group.Conclusions Our results confirm that MMD is relatively common in East Asians,but the rates in China were lower than those in other East Asian countries such as Japan and Korea.The unique epidemiological features,including a relatively weak female predominance and a shift in the highest peak of incidence from children to adults,revealed new sight into MMD.Further research is expected to explore the potential pathogenesis of MMD. | Yixin Sun Guoyu Zhou Jingnan Feng Lu Chen Guozhen Liu Jinxi Wang Qingliang Wang Junyou Yu Xiwang Yang Zheng Yang Pei Gao Shengfeng Wang Siyan Zhan | 2021 | Stroke & Vascular Neurology2021，6，4： | 4 |
| 8 | Mechanical properties and microstructure analysis of refilling friction stir welding on 2219 aluminum alloy显示文摘The 2219 aluminum alloy under refilling friction stir welding (RF-FSW) was investigated. The micrographs showed that the bead could be divided into six zones, and the grain size and shape were greatly different in these zones. According to the microstructure analysis, the weld nugget zone and the shoulder stirring zone consisted of equiaxed grains, while the grains in the heat affected zone were seriously coarsened. It was obvious that bending deformation occurred in the thermo-mechanically affected zone. According to the microhardness analysis, the lowest hardness of the weld was at the thermo-mechanically affected zone, and the microhardness increased with the retraction of the stir-pin. The tensile strength and elongation of the bead were 70% and 80% of the base metal, respectively. The tensile strength was slightly different for the stable stage and the retraction stage, while the elongation decreased in the retraction stage. The mechanical properties and microstructure responded to different retraction speed were analyzed, and it showed that the elongation decreased with increasing retraction speed. | Peilin LI Zhongfeng XU Chun YU Hao LU Junshan YAO Guoyu CHEN | 2012 | Acta Metallurgica Sinica(English Letters)2012，25，3： | 3 |
| 9 | Application study of the awning measure to obstruct solar radiation in permafrost regions on the Qinghai-Tibet Plateau显示文摘With globe warming,road safety will change dramatically,especially within the Qinghai-Tibet Plateau permafrost regions.Because of higher elevation and better atmospheric transparency,the Qinghai-Tibet Plateau has stronger radiation than other regions,which can change the daily variation of ground surface temperature on the Plateau.The awning measure(shading board) is one of the actively protected permafrost measures,which was adopted along the Qinghai-Tibet railway and highway and the Qing-Kang Highway in China.Field test results show that embankment surface month mean net radiation is 60-130 W/m2,but the value is below 20 W/m2 under the shading board,and the reducing level of natural net radiation is 80%-90%.The shading board reduced the heat flow entering into the embankment by 80%-90% or more,with heat entering into the soil on the common embankment,but emitting from the embankment under the shading board.At the same time,ground surface temperature under the shading board is 6-8 ℃ lower than the exposed embankment.Test results show that the shading board measure can rapidly and effectively reduce net radiation and heat flow into the embankment,decrease embankment surface and interior temperature,effectively delay increase rate of soil temperature under globe warming,ensure stability and safety of the embankment,and guarantee unblocked road projects in cold and permafrost regions. | WenJie Feng ZhiZhong Sun Zhi Wen GuoYu Li Ze Zhang WenBing Yu | 2012 | Research in Cold and Arid Regions2012，4，2： | 3 |
| 10 | Extreme Temperature Change of the Last 110 Years in Changchun,Northeast China显示文摘In China and East Asia,the long-term continuous observational data at daily resolution are insufficient,and thus there is a lack of good understanding of the extreme climate variation over the last 100 years plus.In this study,the extreme temperature indices defined by ETCCDI(Expert Team on Climate Change Detection and Indices)and local meteorological administrations were analyzed for Changchun City,Northeast China,by using the daily maximum temperature(Tmax)and daily minimum temperature(Tmin)over 1909?2018.The results showed that extreme cold events,such as cold days,cold nights,frost days,icing days,and low temperature days,decreased significantly at rates of?0.41 d(10 yr)^?1,?1.45 d(10 yr)^?1,?2.28 d(10 yr)^?1,?1.16 d(10 yr)?1 and?1.90 d(10 yr)^?1,respectively.Warm nights increased significantly at a rate of 1.71 d(10 yr)^?1,but warm days decreased slightly and the number of high temperature days decreased at a rate of?0.20 d(10 yr)?1.The frequency of cold surge events increased significantly at a rate of 0.25 d(10 yr)^?1,occurring mainly from the mid-1950s to late-1980s.The average Tmax,average Tmin and extreme Tmin increased at rates of 0.09℃(10 yr)^?1,0.36℃(10 yr)^?1 and 0.54℃(10 yr)^?1,respectively;and extreme Tmax decreased significantly at a rate of?0.17℃(10 yr)^?1.In 1909?2018,1951?2018 and 1979?2018,the indices related to cold events decreased,while the trends of the indices related to warm events were different for different periods. | Xiujing YU Guoyu REN Panfeng ZHANG Jingbiao HU Ning LIU Jianping LI Chenchen ZHANG | 2020 | Advances in Atmospheric Sciences2020，37，4： | 2 |
| 11 | Decreased expression of protease-activated receptor 4 in human gastric cancer显示文摘 | Yong Zhang Guoyu Yu Ping Jiang Yang Xiang Wenliang Li Wenhui Lee Yun Zhang | 2011 | International Journal of Biochemistry and Cell Biology2011，，9： | 2 |
| 12 | Thresholding based on variance and intensity contrast显示文摘 | Qiao Yu Hu Qingmao Qian Guoyu | 2007 | Pattern Recognition2007，40，2： | 1 |
| 13 | Thresholding based on variance and intensity contrast 显示文摘 | Qiao Yu Hua Qingmao Qian Guoyu | 2007 | Pattern Recognition2007，40，2： | 1 |
| 14 | Comparison of anti- corrosion properties of polyurethane based composite coatings with low infrared emissivity 显示文摘 | Wang Yajun Xu Guoyue Yu Huijuan | 2011 | Applied Surface Science2011，257，10： | 1 |
| 15 | Impacts of permafrost mean annual ground temperature and ice content on thermal re- gime of pile foundation of Qinghai-Tibet Power Transmission Line显示文摘 | Li Guoyu Yu Qihao Ma Wei | 2013 | Advanced Materials Research2013，6106，： | 1 |
| 16 | Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller 显示文摘 | YU Zhiyi WANG Guoyu CAO Shuliang | 2009 | Front Mech Eng China2009，4，1： | 1 |
| 17 | Numerical analysis of wind speed variation under awning boards covering embankment side slopes显示文摘 | Wenjie Feng Norbert I. K?mle Yonghong Niu Zhizhong Sun Guoyu Li Wenbing Yu | 2011 | Cold Regions Science and Technology2011，，3： | 1 |
| 18 | Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller显示文摘 | Yu Zhiyi Wang Guoyu Cao Shuliang | 2009 | Front Mech Eng China2009，4，1： | 1 |
| 19 | Characteristics of seed germination in five non-halophytic Chinese desert shrub species显示文摘 | Kazuo Tobe Liping Zhang Guoyu Yu Qiu Hideyuki Shimizu Kenji Omasa | 2001 | Journal of Arid Environments2001，，2： | 1 |
| 20 | Study on design optimization of a crushed stone layer with shading board placed on a railway embankment on warm permafrost显示文摘 | Guoyu Li Ning Li Jiamei Kang Fujun Niu Wenbing Yu Lei Shi Guiquan Bi | 2007 | Cold Regions Science and Technology2007，，1： | 1 |
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