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| 1 | The fractal measurement of experimental images of supersonic turbulent mixing layer显示文摘Flow visualization of supersonic mixing layer has been studied based on the high spatiotemporal resolution Nano-based Planar Laser Scattering(NPLS) method in SML-1 wind tunnel. The corresponding images distinctly reproduced the flow structure of laminar,transitional and turbulent region,with which the fractal measurement can be implemented. Two methods of measuring fractal dimension were introduced and compared. The fractal dimension of the transitional region and the fully developing turbulence region of supersonic mixing layer were measured based on the box-counting method. In the transitional region,the fractal dimension will increase with turbulent intensity. In the fully developing turbulent region,the fractal dimension will not vary apparently for different flow structures,which em-bodies the self-similarity of supersonic turbulence. | ZHAO YuXin YI ShiHe TIAN LiFeng HE Lin CHENG ZhongYu | 2008 | Science China(Physics,Mechanics & Astronomy)2008，51，8： | 24 |
| 2 | Aero-optical aberration measuring method based on NPLS and its application显示文摘The existing methods for measuring aero-optical aberration suffer from several problems,such as low spatiotemporal resolution,sensitivity to environment,and integral effects.A new method for measuring aero-optical aberration of supersonic flow is proposed.Based on the self-developed measuring method of supersonic density field,the wavefront aberration induced by a cross-section of supersonic flow field could be measured by ray-tracing.Compared with other methods,the present one has three significant innovations:(1) high spatiotemporal resolution.Its time resolution is 6 ns,and the spatial resolution can reach up to micrometers;(2) it can avoid the integral effects and study the wavefront aberration induced by the flow field of interest locally;(3) it can also avoid the influence from the test section wall boundary layers and environmental disturbances.The present method was applied to supersonic flow around an optical bow cap.The results of high spatiotemporal resolution reveal fine wavefront structures,and show that shock waves,expansion waves and turbulent boundary layers have different impacts on the wavefront aberration. | YI ShiHe TIAN LiFeng ZHAO YuXin HE Lin CHEN Zhi | 2010 | Chinese Science Bulletin2010，55，31： | 20 |
| 3 | Visualization of coherent structures in a supersonic flat-plate boundary layer显示文摘Flow in a flat-plate zero-pressure-gradient boundary layer at Mach 3 was visualized via nanoparticle-based planar laser scattering (NPLS). Coherent structures such as an individual hairpin vortex and hairpin packet were identified in the streamwise-wall-normal plane on the basis of the now accepted hairpin model. Λ-shaped vortices were found in a staggered pattern in the stream-wise-spanwise plane, which indicated H-type transition in the present experiments. This is the direct evidence (in the form of flow visualization) of such coherent structures in a supersonic boundary layer. A series of NPLS images taken in streamwise-spanwise planes at different heights is presented, and the three-dimensional structures of the supersonic boundary layer agree well with the hairpin model. | HE Lin YI ShiHe ZHAO YuXin TIAN LiFeng CHEN Zhi | 2011 | Chinese Science Bulletin2011，56，6： | 19 |
| 4 | The experimental study of interaction between shock wave and turbulence显示文摘The interaction between shock wave and turbulence has been studied in supersonic turbulent mix layer wind tunnel. The interaction between oblique shock wave and turbulent boundary layer and the influence of large vortex in mix layer on oblique shock wave have been observed by NPLS technique. From NPLS image, not only complex flow structure is observed but also time-dependent supersonic flow visualization is realized. The mechanism of interaction between shock wave and turbulence is discussed based on high quality NPLS image. | ZHAO YuXin YI ShiHe HE Lin CHENG ZhongYu TIAN LiFeng | 2007 | Chinese Science Bulletin2007，52，10： | 18 |
| 5 | Study of density field measurement based on NPLS technique in supersonic flow显示文摘Due to the influence of shock wave and turbulence, supersonic density field exhibits strongly inhomogeneous and unsteady characteristics. Applying traditional density field measurement techniques to supersonic flows yields three problems: low spatiotemporal resolution, limitation of measuring 3D density field, and low signal to noise ratio (SNR). A new method based on Nano-based Planar Laser Scattering (NPLS) technique is proposed in this paper to measure supersonic density field. This method measures planar transient density field in 3D supersonic flow by calibrating the relationship between density and concentration of tracer particles, which would display the density fluctuation due to the influence of shock waves and vortexes. The application of this new method to density field measurement of supersonic optical bow cap is introduced in this paper, and the results reveal shock wave, turbulent boundary layer in the flow with the spatial resolution of 93.2 μm/pixel. By analyzing the results at interval of 5 μs, temporal evolution of density field can be observed. | TIAN LiFeng YI ShiHe ZHAO YuXin HE Lin CHENG ZhongYu | 2009 | Science China(Physics,Mechanics & Astronomy)2009，52，9： | 15 |
| 6 | An experimental study of aero-optical aberration and dithering of supersonic mixing layer via BOS显示文摘The optical performance of supersonic mixing layer is heavily deteriorated by the aero-optical aberration and dithering of coherent structures, but current measuring methods limit the spatiotemporal resolution in relevant studies. A high resolution whole-field aero-optical aberration and dithering measuring method based on the Background Orient Schlieren (BOS) technique was studied. The systematic structure, sensitivity and resolution of BOS are analyzed in this paper. The aero-optical aberration and dithering of streamwise structures in supersonic mixing layers were quantificationally studied with BOS. The aberration field of spanwise structures revealed the ribbon-like aberration structures, which heavily restrict the optical performance of a mixing layer. The quantifications of aero-optical aberration and dithering are very important in studying aero-optical performance of supersonic mixing layer. | ZHAO YuXin , YI ShiHe, TIAN LiFeng, HE Lin & CHENG ZhongYu College of Aerospace and Material Engineering, National University of Defense Technology, Changsha 410073, China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，1： | 13 |
| 7 | Multiresolution analysis of density fluctuation in supersonic mixing layer显示文摘Due to the difficulties in measuring supersonic density field, the multiresolution analysis of supersonic mixing layer based on experimental images is still a formidable challenge. By utilizing the recently developed nanoparticle based planar laser scattering method, the density field of a supersonic mixing layer was measured at high spatiotemporal resolution. According to the dynamic behavior of coherent structures, the multiresolution characteristics of density fluctuation signals and density field images were studied based on Taylor’s hypothesis of space-time conversion and wavelet analysis. The wavelet coefficients reflect the characteristics of density fluctuation signals at different scales, and the detailed coefficients reflect the differences of approximation at adjacent levels. The density fluctuation signals of supersonic mixing layer differ from the periodic sine signal and exhibit similarity to the fractal Koch signal. The similarity at different scales reveals the fractal characteristic of mixing layer flowfield. The two-dimensional wavelet decomposition and reconstruction of density field images extract the approximate and detailed signals at different scales, which effectively resolve the characteristic structures of the flowfield at different scales. | ZHAO YuXin1, YI ShiHe, TIAN LiFeng, HE Lin & CHENG ZhongYu College of Aerospace and Material Engineering, National University of Defense Technology, Changsha 410073, China | 2010 | Science China(Technological Sciences)2010，53，2： | 11 |
| 8 | Grey 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 | 2015 | Neuroscience Bulletin2015，31，1： | 11 |
| 9 | A flow control study of a supersonic mixing layer via NPLS显示文摘The flow control of a supersonic mixing layer was studied in a supersonic mixing layer wind tunnel with convective Mach number (Mc) at 0.5. The passive control of the mixing layer was achieved by perturbation tapes on the trailing edge of the splitter plate. The control effects of 2D and 3D perturbation tapes with different sizes were compared. The mixing layer was visualized via NPLS,and the transient fine structures were identifiable in NPLS images,which were used to analyze the effects of flow control. The results show that the 2D tapes can enhance the 2D characteristic of the mixing layer,delaying mixing layer transition; and the 3D tapes can enhance the 3D characteristic of the mixing layer,advancing mixing layer transition. 3D structures of the mixing layer were visualized,and the H-type Λ vortexes were found with 3D tapes control. | YI ShiHe HE Lin ZHAO YuXin TIAN LiFeng CHENG ZhongYu | 2009 | Science China(Physics,Mechanics & Astronomy)2009，52，12： | 10 |
| 10 | Aero-optical wavefront measurement technique based on BOS and its applications显示文摘A collimated light beam will be refracted if it propagates through a flow-field with index-of-refraction variations,and its wavefront will be distorted.If we measure the deflection angle of the light beam,the gradient of the wavefront can be obtained using the Malus law,and the wavefront aberration can be computed with a reconstruction algorithm.Two characteristics of background oriented schlieren(BOS) are conducive to wavefront aberration measurement:BOS can be used to measure the deflection angle of a light beam by measuring the displacement field between the reference image and the experiment image.Moreover,in a BOS system of Schlieren mode,only the ray perpendicular to the background image can be captured with a camera.This is helpful to measure wavefront aberrations that occur after a planar wavefront has passed through the flow-field.Based on these characteristics of BOS of Schlieren mode,a new wavefront measurement technique,which is called the BOS-based wavefront technique(BOS-WT),is proposed in this paper.It works by constructing the relationship between the displacement of the background image and the aero-optical wavefront gradient and uses the Southwell wavefront reconstruction algorithm.A BOS-WT system was assembled,and its temporal resolution was found to be 6 ns,and its temporal-correlation resolution reached 0.2 μs.A BOS-WT can measure the time-correlation transient wavefront quantitatively.It is simple and easy to operate.In this paper,we also present a study of the aero-optical performance of supersonic mixing layer based on our BOS-WT transient wavefronts at an interval of 5 μs.The results showed the wavefront was transient and distorted after it had passed through the mixing layer.Through the analysis of the data at the 5 μs interval,the temporal evolution of wavefront can be obtained. | TIAN LiFeng YI ShiHe ZHAO YuXin HE Lin CHEN Zhi | 2011 | Chinese Science Bulletin2011，56，22： | 10 |
| 11 | Wheat 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 | 2022 | Science China(Life Sciences)2022，65，9： | 9 |
| 12 | Density field measurement and approximate reconstruction of supersonic mixing layer显示文摘The density field measurement of supersonic mixing layer based on the nanoparticle-based planar laser scattering method was studied.The calibration of experimental images was analyzed,and the relation between tracer particles concentration and local density of flowfield was calibrated with oblique shockwave experiment.According to the characteristic of mixing layer images,the influence of uneven light intensity distribution was calibrated.With these calibration methods,the density field of supersonic mixing layer with convective Mach number at 0.12 was measured.By analyzing the spanwise vortical structures and streamwise density field,the three dimensional(3D) density field was approximately reconstructed,which apparently reflected the 3D structure of supersonic mixing layer. | ZHAO YuXin YI ShiHe TIAN LiFeng HE Lin CHENG ZhongYu | 2010 | Chinese Science Bulletin2010，55，19： | 7 |
| 13 | Evaporation of liquid fuel droplet at supercritical conditions显示文摘A comprehensive analysis of liquid fuel droplet evaporation at supercritical conditions is performed.The numerical model is based on complete time-dependent conservation equations,with a full account of variable thermophysical properties and vapor-liquid interfacial thermodynamics.And the model employs the Peng-Robinson(PR)equation of state(EOS).As a specific example,problems involving n-heptane droplet in nitrogen gas are investigated.The results indicate that the increase of ambient pressure and temperature results in the increase of surface temperature rise rate and surface regression rate.The transition from subcritical state to supercritical state can occur at the droplet surface when the droplet evaporates in a strongly supercritical environment. | HE Peng LI YunQing ZHAO LiFeng | 2011 | Science China(Technological Sciences)2011，54，2： | 7 |
| 14 | Switching off IMMP2L signaling drives senescence via simultaneous metabolic alteration and blockage of cell death显示文摘 | Lifeng Yuan Linhui Zhai Lili Qian De Huang Yi Ding Handan Xiang Xiaojing Liu J. Will Thompson Juan Liu Yong-Han He Xiao-Qiong Chen Jing Hu Qing-Peng Kong Minjia Tan Xiao-Fan Wang | 2018 | Cell Research2018，28，6： | 7 |
| 15 | Experimental study of a supersonic turbulent boundary layer using PIV显示文摘Particle image velocimetry was applied to the study of the statistical properties and the coherent structures of a flat plate turbulent boundary layer at Mach 3. The nanoparticles with a good flow-following capability in supersonic flows were adopted as the tracer particles in the present experiments. The results show that the Van Driest transformed mean velocity profile satisfies the incompressible scalings and reveals a log-law region that extends to y/ =0.4, which is further away from the wall than that in incompressible boundary layers. The Reynolds stress profiles exhibit a plateau-like region in the log-law region. The hairpin vortices in the streamwise-wall-normal plane are identified using different velocity decompositions, which are similar to the results of the flow visualization via NPLS technique. And multiple hairpin vortices are found moving at nearly the same velocity in different regions of the boundary layer. In the streamwise-spanwise plane, elongated streaky structures are observed in the log-law region, and disappear in the outer region of the boundary layer, which is contrary to the flow visualization results. | HE Lin YI ShiHe ZHAO YuXin TIAN LiFeng CHEN Zhi | 2011 | Science China(Physics,Mechanics & Astronomy)2011，54，9： | 6 |
| 16 | The effects of EGR and ignition timing on emissions of GDI engine显示文摘The effects of EGR and ignition timing on engine emissions and combustion were studied through an experiment carried out on an air-guided GDI engine.The test results showed that the ignition timing significantly affected the GDI engine emissions,that the NOx emissions significantly reduced when the ignition timing was retarded,and that NOx emissions decreased with the EGR level increasement.A higher EGR rate could reduce CO emissions while the CO emissions were less affected by the ignition timing.The HC emissions decreased at a lower EGR rate.At 2500 r/min,an appropriate EGR rate could cut down CO emissions.The exhaust gas temperature could significantly decrease with improving the EGR rate,and the exhaust gas temperature at 2500 r/min was clearly higher than that at 1850 r/min.The nucleation mode particles increased clearly,the accumulation mode particle number decreased gradually with the increase of EGR rate,and the typical particle size of nucleation mode particle was in the range of 10–25 nm. | ZHAO LiFeng YU XiuMin QIAN DingChao DONG Wei SUN Ping HE Ling YANG Song | 2013 | Science China(Technological Sciences)2013，56，12： | 5 |
| 17 | Theoretical and simulation research of hydrodynamic instabilities in inertial-confinement fusion implosions显示文摘Inertial fusion energy(IFE)has been considered a promising,nearly inexhaustible source of sustainable carbon-free power for the world's energy future.It has long been recognized that the control of hydrodynamic instabilities is of critical importance for ignition and high-gain in the inertial-confinement fusion(ICF)hot-spot ignition scheme.In this mini-review,we summarize the progress of theoretical and simulation research of hydrodynamic instabilities in the ICF central hot-spot implosion in our group over the past decade.In order to obtain sufficient understanding of the growth of hydrodynamic instabilities in ICF,we first decompose the problem into different stages according to the implosion physics processes.The decomposed essential physics processes that are associated with ICF implosions,such as Rayleigh-Taylor instability(RTI),Richtmyer-Meshkov instability(RMI),Kelvin-Helmholtz instability(KHI),convergent geometry effects,as well as perturbation feed-through are reviewed.Analytical models in planar,cylindrical,and spherical geometries have been established to study different physical aspects,including density-gradient,interface-coupling,geometry,and convergent effects.The influence of ablation in the presence of preheating on the RTI has been extensively studied by numerical simulations.The KHI considering the ablation effect has been discussed in detail for the first time.A series of single-mode ablative RTI experiments has been performed on the Shenguang-Ⅱlaser facility.The theoretical and simulation research provides us the physical insights of linear and weakly nonlinear growths,and nonlinear evolutions of the hydrodynamic instabilities in ICF implosions,which has directly supported the research of ICF ignition target design.The ICF hot-spot ignition implosion design that uses several controlling features,based on our current understanding of hydrodynamic instabilities,to address shell implosion stability,has been briefly described,several of which are novel. | LiFeng Wang WenHua Ye XianTu He JunFeng Wu ZhengFeng Fan Chuang Xue HongYu Guo WenYong Miao YongTeng Yuan JiaQin Dong Guo Jia Jing Zhang YingJun Li Jie Liu Min Wang YongKun Ding WeiYan Zhang | 2017 | Science China(Physics,Mechanics & Astronomy)2017，60，5： | 4 |
| 18 | An experimental study on fine structures of supersonic laminar/turbulent flow over a backward-facing step based on NPLS显示文摘Fine structures of supersonic flow over a 5 mm high backward facing step(BFS),including expansion wave fan,reattachment shock,supersonic boundary layer were measured in a Ma=3.0 low-noise indraft wind tunnel.By varying the superficial roughness of the wall upstream from the step,supersonic laminar flow and supersonic turbulent flow could be formed over a BFS.Measurements on the spatiotemporal features of the holistic flow field and the fine structures in four typical regions were carried out using NPLS(nano-based planar laser scattering).Flow structures,including expansion wave fan,reattachment shock,supersonic boundary layer and its separation,reattachment and redevelopment are revealed by measuring the holistic structure of the transient flow field.Comparing the two time-averaged flow fields with each other,it is apparent that supersonic turbulent flow over a BFS(STF-BFS) has a larger expansion angle and a shorter recirculation region,and its redeveloped boundary layer increases at a smaller obliquity while the angle of reattachment shock is the same for the supersonic laminar flow over a BFS(SLF-BFS).With regard to time-evolution features,the K-H vortices in the SLF-BFS suffers from shearing,expansion,reattachment and three-dimensional effects while in the STF-BFS large-scale structures are affected by the incline and distortion at the reattachment point due to expansion,viscosity and reverse-pressure.Studies on local regions indicate that in the SLF-BFS,the emergence of compression waves which distinctly converge into a reattachment shock is due to the local convective Mach number and the inducement of K-H vortices in the free shear layer.Nevertheless,in the STF-BFS,compression waves and K-H vortices are barely evident,and the formation of a reattachment shock is related to the wall compressive effect. | CHEN Zhi YI ShiHe HE Lin TIAN LiFeng ZHU YangZhu | 2012 | Chinese Science Bulletin2012，57，6： | 4 |
| 19 | Sunway supercomputer architecture towards exascale computing:analysis and practice显示文摘In recent years,the improvements of system performance and energy efficiency for supercomputers have faced increasing challenges,which create more intensive demands on the architecture design for realizing exascale computing.This paper first analyzes the main requirements of exascale computing on the aspects of the parallel computing application and supercomputing center operation.Afterwards,a mapping scheme of'demands-challenges-architecture'is proposed.Then,the major challenges of exascale supercomputer,such as scalability,power consumption,data movement,programming and availability,are thoroughly analyzed,and the corresponding appropriate solutions are proposed.Moreover,this paper proposes the Sunway computer architecture towards exascale computing in which the many-core processor,network chipset and software system are all domestically-designed.The technology roadmap of Sunway supercomputer will hold the comprehensive design methods for the architecture,including the processor,interconnect network,assembly structure,power supply,cooling system,system software,parallel algorithm and application support,promising great advances for exascale supercomputing. | Jiangang GAO Fang ZHENG Fengbin QI Yajun DING Hongliang LI Hongsheng LU Wangquan HE Hongmei WEI Lifeng JIN Xin LIU Daoyong GONG Fei WANG Yan ZHENG Honghui SUN Zhou ZHOU Yong LIU Hongtao YOU | 2021 | Science China(Information Sciences)2021，64，4： | 3 |
| 20 | Spatiotemporal dynamics of the vegetation in Ningxia,China using MODIS imagery显示文摘The vegetation in the Ningxia Hui Autonomous Region(henceforth,Ningxia)of north-western China plays an important role in guarding regional ecological safety and sustainable development.However,it is unclear how climate affects vegetation growth in terms of seasonality and various vegetation types in Ningxia.Based on remote sensing vegetation index from 2001 to 2016,climatic parameters,and the Chinese vegetation type data,this article examines the spatiotemporal effects of climate parameters on vegetation.The relative importance to variability in the normalized difference vegetation index(NDVI)for different seasons and various vegetated types is also determined.The results demonstrate that the vegetation increased from 2001 to 2016 in Ningxia.The rate of NDVI increase was fastest in summer and slowest in spring.Areas with significant increases in vegetation occurred primarily in the southern mountain,Liupan Mountain,and central arid areas.Degraded vegetation occurred in the Yellow River irrigation area with intense human activity influence.The vegetation in most areas of Ningxia will continue to increase in the future.The sensitivity of vegetation to temperature,precipitation,sunshine duration,and wind velocity showed significantly seasonal variability.Sunshine duration and wind velocity were important climatic factors affecting vegetation growth in Ningxia.However,the impact of summer precipitation variation on summer NDVI(SMN)demonstrated a time lag effect.The impact of climate variation on vegetation was distinct among various vegetation types.Moreover,the spatial pattern of vegetation in Ningxia was also impacted by human activities. | Yi HE Haowen YAN Lei MA Lifeng ZHANG Lisha QIU Shuwen YANG | 2020 | Frontiers of Earth Science2020，14，1： | 3 |
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