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18篇 您的检索式:作者名="YouGang Wang"
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1Induction of xenogeneic islet transplantation tolerance by simultaneously blocking CD28-B7 and OX40-OX40L co-stimulatory pathways显示文摘It has been demonstrated that prolonged graft survival can be achieved through inhibiting the activation of T cells, and addition of soluble CTLA4Ig and OX40Ig proteins to mixed lymphocyte reactions can effectively inhibit T cell proliferation. To explore the potential of this type of treatment in xenotransplantation, we infected streptozotocin-induced diabetic BalB/c mice (H-2d) (200 mg/kg, IV) with 5×108 pfu AdCTLA4Ig-IRES-OX40Ig on day 1 before islets trans-plantation through the tail vein. The results showed that this treatment prolonged the islet xeno-grafts survival significantly. The reaction to exogenous glucose stimulation was normal and the cytokine secretion of the type Th1 cells was inhibited. The AdCTLA4Ig-IRES-OX40Ig-mediated treatment effectively induced the T cells into anergy and the Th1/Th2 cells into deviation. These results strongly supported the therapeutic potential of blockade of costimulation by Ad-CTLA4Ig-IRES-OX40Ig genes transfer in inducing the organ transplantation tolerance.WANG Guangming FENG Yougang HAO Jie LI Ailing GAO Xiang XIE Shusheng 2005Science China(Life Sciences)2005,48,5:4
2Internal Resonances for the Heave Roll and Pitch Modes of a Spar Platform Considering Wave and Vortex Exciting Loads in Heave Main Resonance显示文摘The objective of this paper is to study the nonlinear coupling internal resonance of the heave,roll,and pitch response performance of a spar platform when their frequencies are in the ratio of 2:1:1 under wave and vortex exciting loads.The three degree-of-freedom(DOF)nonlinear coupled equations are established by considering a time-varying wet surface with a first-order wave force in heave and pitch and a vortex-induced force in roll.The first-order steady-state response is solved using the multi-scale method in heave main resonance.The multiple solutions of the motion equations are discussed using the analytic method and a numerical simulation.A sensitivity analysis is conducted to test the influence of the damping and internal detuning parameter.The regions of multiple solutions are found,and the jump phenomenon exists with the changes of the wave excitation.The regions of multiple solutions depend on the values of damping and detuning parameter.Wei Li Yougang Tang Bin Wang Yan Li 2018Journal of Marine Science and Application2018,17,2:2
3Generation of ApoE deficient dogs via combination of embryo injection of CRISPR/Cas9 with somatic cell nuclear transfer显示文摘Atherosclerotic cardiovascular disease is the leading cause of death in the world which is resulted from complex interactions among multiple genetic and environmental factors(WHO).Atherosclerosis is a chronic inflammatory disease characterized by accumulation of lipids in the arterial wall(Gofman and Lindgren,1950).Tremendous clinical and experimental efforts haveChong Feng Xiaomin Wang Hui Shi Quanmei Yan Min Zheng Jing Li Quanjun Zhang Yumin Qin Yougang Zhong Jidong Mi Liangxue Lai 2018Journal of Genetics and Genomics2018,45,1:2
4Effects of Second-Order Sum-and Difference-Frequency Wave Forces on the Motion Response of a Tension-Leg Platform Considering the Set-down Motion显示文摘This paper presents a study on the motion response of a tension-leg platform(TLP) under first-and second-order wave forces, including the mean-drift force, difference and sum-frequency forces. The second-order wave force is calculated using the full-field quadratic transfer function(QTF). The coupled effect of the horizontal motions, such as surge, sway and yaw motions, and the set-down motion are taken into consideration by the nonlinear restoring matrix. The time-domain analysis with 50-yr random sea state is performed. A comparison of the results of different case studies is made to assess the influence of second-order wave force on the motions of the platform. The analysis shows that the second-order wave force has a major impact on motions of the TLP. The second-order difference-frequency wave force has an obvious influence on the low-frequency motions of surge and sway, and also will induce a large set-down motion which is an important part of heave motion. Besides, the second-order sum-frequency force will induce a set of high-frequency motions of roll and pitch. However, little influence of second-order wave force is found on the yaw motion.WANG Bin TANG Yougang CAI Runbo 2018Journal of Ocean University of China2018,17,2:2
5Hopf Bifurcation of a Nonresident Computer Virus Model with Delay显示文摘In this paper, a delayed nonresident computer virus model with graded infection rate is considered in which the following assumption is imposed: latent computers have lower infection ability than infectious computers. With the aid of the bifurcation theory, sufficient conditions for stability of the infected equilibrium of the model and existence of the Hopf bifurcation are established. In particular, explicit formulae which determine direction and stability of the Hopf bifurcation are derived by means of the normal form theory and the center manifold reduction for functional differential equations. Finally, a numerical example is given in order to show the feasibility of the obtained theoretical findings.Zizhen Zhang Yougang Wang Massimiliano Ferrara 2018Analysis in Theory and Applications2018,34,3:1
6A research and application of parametric modeling techno- logy for truck frame base on ANSYS 显示文摘Chai Shan Wang Yougang Wang Pengcheng 2011Key Enginee- ring Materials2011,,:1
7CFD Simulation of the Vertical Motion Characteristics of the Moonpool Fluid for the Truss Spar显示文摘The research purpose of this paper is to estimate the impacts of the parameters of the guide plate on the vertical motion characteristics of the moonpool fluid. With the volume of fluid(VOF) method, three-dimensional models of the moonpool fluid motions of the truss spar platform are established. Simulation results are then presented for the moonpool forced oscillation by employing the dynamic mesh method and user-defined functions in FLUENT. The motions of the moonpool fluid and the loads on the guide plates are obtained for both cases of square-ring and crisscross. The results show that the shape and area of the guide plate at the bottom of the moonpool have a significant impact on the physical parameters of the moonpool, including the load on the moonpool guide plate, motion form of the moonpool fluid and the mass flow rate.Bin Wang Liqin Liu Yougang Tang 2014Journal of Marine Science and Application2014,13,1:1
8Detecting HI Galaxies with Deep Neural Networks in the Presence of Radio Frequency Interference显示文摘In the neutral hydrogen(H I)galaxy survey,a significant challenge is to identify and extract the H I galaxy signal from the observational data contaminated by radio frequency interference(RFI).For a drift-scan survey,or more generally a survey of a spatially continuous region,in the time-ordered spectral data,the H I galaxies and RFI all appear as regions that extend an area in the time-frequency waterfall plot,so the extraction of the H I galaxies and RFI from such data can be regarded as an image segmentation problem,and machine-learning methods can be applied to solve such problems.In this study,we develop a method to effectively detect and extract signals of H I galaxies based on a Mask R-CNN network combined with the PointRend method.By simulating FAST-observed galaxy signals and potential RFI impact,we created a realistic data set for the training and testing of our neural network.We compared five different architectures and selected the best-performing one.This architecture successfully performs instance segmentation of H I galaxy signals in the RFI-contaminated time-ordered data,achieving a precision of 98.64%and a recall of 93.59%.Ruxi Liang Furen Deng Zepei Yang Chunming Li Feiyu Zhao Botao Yang Shuanghao Shu Wenxiu Yang Shifan Zuo Yichao Li Yougang Wang Xuelei Chen 2023Research in Astronomy and Astrophysics2023,23,11:0
9Application of Regularization Methods in the Sky Map Reconstruction of the Tianlai Cylinder Pathfinder Array显示文摘The Tianlai cylinder pathfinder is a radio interferometer array to test 21 cm intensity mapping techniques in the post-reionization era.It works in passive drift scan mode to survey the sky visible in the northern hemisphere.To deal with the large instantaneous field of view and the spherical sky,we decompose the drift scan data into m-modes,which are linearly related to the sky intensity.The sky map is reconstructed by solving the linear interferometer equations.Due to incomplete uv coverage of the interferometer baselines,this inverse problem is usually ill-posed,and regularization method is needed for its solution.In this paper,we use simulation to investigate two frequently used regularization methods,the Truncated Singular Value Decomposition(TSVD),and the Tikhonov regularization techniques.Choosing the regularization parameter is very important for its application.We employ the generalized cross validation method and the L-curve method to determine the optimal value.We compare the resulting maps obtained with the different regularization methods,and for the different parameters derived using the different criteria.While both methods can yield good maps for a range of regularization parameters,in the Tikhonov method the suppression of noisy modes are more gradually applied,produce more smooth maps which avoids some visual artefacts in the maps generated with the TSVD method.Kaifeng Yu Shifan Zuo Fengquan Wu Yougang Wang Xuelei Chen 2024Research in Astronomy and Astrophysics2024,24,2:0
10The Tianlai Cylinder Pathfinder array: System functions and basic performance analysis显示文摘The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe,with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state.Each of its three parallel cylinder reflectors is oriented in the north-south direction,and the array has a large field of view.As the Earth rotates,the northern sky is observed by drift scanning.The array is located in Hongliuxia,a radio-quiet site in Xinjiang,and saw its first light in September 2016.In this first data analysis paper for the Tianlai cylinder array,we discuss the sub-system qualification tests,and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018.We show typical interferometric visibility data,from which we derive the actual beam profile in the east-west direction and the frequency band-pass response.We describe also the calibration process to determine the complex gains for the array elements,either using bright astronomical point sources,or an artificial on site calibrator source,and discuss the instrument response stability,crucial for transit interferometry.Based on this analysis,we find a system temperature of about 90 K,and we also estimate the sensitivity of the array.JiXia Li ShiFan Zuo FengQuan Wu YouGang Wang JuYong Zhang ShiJie Sun YiDong Xu ZiJie Yu Reza Ansari YiChao Li Albert Stebbins Peter Timbie YanPing Cong JingChao Geng Jie Hao QiZhi Huang JianBin Li Rui Li DongHao Liu YingFeng Liu Tao Liu John PMarriner ChenHui Niu Ue-Li Pen Jeffery BPeterson HuLi Shi Lin Shu YaFang Song HaiJun Tian GuiSong Wang QunXiong Wang RongLi Wang WeiXia Wang Xin Wang KaiFeng Yu Jiao Zhang BoQin Zhu JiaLu Zhu XueLei Chen 2020Science China(Physics,Mechanics & Astronomy)2020,63,12:0
11Classifying Globular Clusters and Applying them to Estimate the mass of the Milky Way显示文摘We combine the kinematics of 159 globular clusters(GCs) provided by the Gaia Early Data Release 3(EDR3) with other observational data to classify the GCs,and to estimate the mass of the Milky Way(MW).We use the agemetallicity relation,integrals of motion,action space and the GC orbits to identify the GCs as either formed in situ(Bulge and Disk) or ex situ(via accretion).We find that 45.3% have formed in situ,while 38.4% may be related to known merger events:Gaia-Sausage-Enceladus,the Sagittarius dwarf galaxy,the Helmi streams,the Sequoia galaxy and the Kraken galaxy.We also further identify three new sub-structures associated with the Gaia-Sausage-Enceladus.The remaining 16.3% of GCs are unrelated to the known mergers and thought to be from small accretion events.We select 46 GCs which have radii 8.0 GuangChen Sun Yougang Wang Chao Liu Richard J.Long Xuelei Chen Qi Gao 2023Research in Astronomy and Astrophysics2023,23,1:0
12Constraining Brans–Dicke Cosmology with the CSST Galaxy Clustering Spectroscopic Survey显示文摘The Brans-Dicke(BD)theory is the simplest Scalar-Tensor theory of gravity,which can be considered as a candidate of modified Einstein’s theory of general relativity.In this work,we forecast the constraints on BD theory in the CSST galaxy clustering spectroscopic survey with a magnitude limit~23 AB mag for point-source 5σdetection.We generate mock data based on the zCOSMOS catalog and consider the observational and instrumental effects of the CSST spectroscopic survey.We predict galaxy power spectra in the BD theory from z=0 to 1.5,and the galaxy bias and other systematical parameters are also included.The Markov Chain Monte Carlo technique is employed to find the best-fits and probability distributions of the cosmological and systematical parameters.A BD parameterζis introduced,which satisfiesζ=In(1+(1/ω)).We find that the CSST spectroscopic galaxy clustering survey can give|ξ|<10^(-2),or equivalently|ω|>O(10^(2))and|■/G|<10^(-13),under the assumptionζ=0.These constraints are almost at the same order of magnitude compared to the joint constraints using the current cosmic microwave background,baryon acoustic oscillations and TypeⅠa supernova data,indicating that the CSST galaxy clustering spectroscopic survey would be powerful for constraining the BD theory and other modified gravity theories.Anda Chen Yan Gong Fengquan Wu Yougang Wang Xuelei Chen 2022Research in Astronomy and Astrophysics2022,22,5:0
13The Electromagnetic Characteristics of the Tianlai Cylindrical Pathfinder Array显示文摘A great challenge for 21 cm intensity mapping experiments is the strong foreground radiation which is orders of magnitude brighter than the 21 cm signal.Removal of the foreground takes advantage of the fact that its frequency spectrum is smooth while the redshifted 21 cm signal spectrum is stochastic.However,a complication is the nonsmoothness of the instrument response.This paper describes the electromagnetic simulation of the Tianlai cylinder array,a pathfinder for 21 cm intensity mapping experiments.Due to the vast scales involved,a direct simulation requires a large amount of computing resources.We have made the simulation practical by using a combination of methods:first simulate a single feed,then an array of feed units,finally with the feed array and a cylindrical reflector together,obtain the response for a single cylinder.We studied its radiation pattern,bandpass response and the effects of mutual coupling between feed units,and compared the results with observation.Many features seen in the measurement result are reproduced well in the simulation,especially the oscillatory features which are associated with the standing waves on the reflector.The mutual coupling between feed units is quantified with Sparameters,which decrease as the distance between the two feeds increases.Based on the simulated S-parameters,we estimate the correlated noise which has been seen in the visibility data,and the results show very good agreement with the data in both magnitude and frequency structures.These results provide useful insights on the problem of 21 cm signal extraction for real instruments.Shijie Sun Jixia Li Fengquan Wu Peter Timbie Reza Ansari Jingchao Geng Huli Shi Albert Stebbins Yougang Wang Juyong Zhang Xuelei Chen 2022Research in Astronomy and Astrophysics2022,22,6:0
14Multi-Objective Optimization of Mechanical Running Conditions of Large Scale Statically Indeterminate Rotary Kiln显示文摘Combined with the second rotary kiln of Alumina Factory in Great Wall Aluminum Company, the mechanics characteristics of statically indeterminate large-scale rotary kiln with variable cross-sections is analyzed. In order to adjusting the running axis of rotary kiln, taking the force equilibrium of the rollers and the minimum of relative axis deflection as the optimization goal, the multi-objective optimization model of mechanical running conditions of kiln rotary is set up. The mechanical running conditions of the second rotary kiln after multi-objective optimization adjustment are compared with those before adjustment and after routine adjustment. It shows that multi-objective optimization adjustment can make axis as direct as possible and can distribute kiln loads equally.Hu Xiaoping Xiao Yougang Wang Guangbin 2006工程科学(英文版)2006,4,1:0
15A Fast Radio Burst Backend for the Tianlai Dish Pathfinder Array显示文摘The Tianlai Dish Pathfinder Array is a radio interferometer array consisting of 16 six-meter dish antennas.The original digital backend integration time is at the seconds level,designed for H I intensity mapping experiment.A new digital backend with millisecond response is added to enable it to search for fast radio burst during its observations.The design and calibration of this backend,and the real time search pipeline for it are described in this paper.It is capable of forming 16 digital beams for each linear polarization,covering an area of 19.6 square degrees.The search pipeline is capable of searching for,recording and classifying FRBs automatically in real time.In commissioning,we succeeded in capturing the signal pulses from the pulsars PSR B0329+54 and B2021+51.Zijie Yu Furen Deng Shijie Sun Chenhui Niu Jixia Li Fengquan Wu Wei-Yang Wang Yougang Wang Hui Feng Lin Shu Jie Hao Reza Ansari Albert Stebbins Xuelei Chen 2022Research in Astronomy and Astrophysics2022,22,12:0
16Combination of CTLA4-FasL gene transfer and allogeneic bone marrow transplantation led to durable macrochimerism and donor-specific tolerance in mouse model显示文摘Mixed hemopoietic chimerism is capable of inducing donor specific tolerance, thus eliminating the chronic immunosuppressive therapy following organ trans- plantation. As yet no safe and effective tolerance protocol is available for clinical implementation. Here we describe an alternative nonmyeloablative based strategy of using a single injection of recombination adenovirus vector encoding CTLA4-FasL fusing gene and donor bone marrow cells to promote durable mixed macrochimerism (>20% on 140 d). Chimeras exhibited robust donor-specific tolerance, as evi- denced by acceptance of fully allogeneic skin grafts (the mean survival time (MST)>200 d) and rejection of third- party skin grafts in a normal manner (MST<10 d). In this model, the frequencies of helper T lymphocyte precursor (HTLp) and cytotoxic T lymphocyte precursor (CTLp) were greatly reduced on day 14 after transplantation, suggesting that CTLA4-FasL led to rapid systemic peripheral tolerance to facilitate the bone marrow engraftment, while both HTLp and CTLp remained at low level only in recipient mice with mixed chimerism on day 140 after transplantation, demon- strating that long-term skin grafts tolerance was associated with stable mixed chimerism, and central deletion of donor specific T cell may be the main mechanism for tolerance maintenance.FENG Yougang WANG Guangming HAO Jie LI Ailing YUAN Guohong LI Chong ZENG Fuqing XlE Shusheng 2005Chinese Science Bulletin2005,50,20:0
17A Simulation of Calibration and Map-making Errors of the Tianlai Cylinder Pathfinder Array显示文摘The Tianlai cylinder array is a pathfinder for developing and testing 21 cm intensity mapping techniques.In this paper,we use numerical simulation to assess how its measurement is affected by thermal noise and the errors in calibration and map-making process,and the error in the sky map reconstructed from a drift scan survey.Here we consider only the single frequency,unpolarized case.The beam is modeled by fitting to the electromagnetic simulation of the antenna,and the variations of the complex gains of the array elements are modeled by Gaussian processes.Mock visibility data are generated and run through our data processing pipeline.We find that the accuracy of the current calibration is limited primarily by the absolute calibration,where the error comes mainly from the approximation of a single dominating point source.We then studied the m-mode map-making with the help of Moore-Penrose inverse.We find that discarding modes with singular values smaller than a threshold could generate visible artifacts in the map.The impacts of the residue variation of the complex gain and thermal noise are also investigated.The thermal noise in the map varies with latitude,being minimum at the latitude passing through the zenith of the telescope.The angular power spectrum of the reconstructed map show that the current Tianlai cylinder pathfinder,which has a shorter maximum baseline length in the North-South direction,can measure modes up to l■2πb_(NS)/λ~200 very well,but would lose a significant fraction of higher angular modes when noise is present.These results help us to identify the main limiting factors in our current array configuration and data analysis procedure,and suggest that the performance can be improved by reconfiguration of the array feed positions.Kaifeng Yu Fengquan Wu Shifan Zuo Jixia Li Shijie Sun Yougang Wang Xuelei Chen 2023Research in Astronomy and Astrophysics2023,23,10:0
18Stellar Dynamical Modeling—Counting Conserved Quantities显示文摘Knowing the conserved quantities that a galaxy’s stellar orbits conform to is important in helping us understand the stellar distribution and structures within the galaxy.Isolating integrals of motion and resonances are particularly important,non-isolating integrals less so.We compare the behavior and results of two methods for counting the number of conserved quantities,one based on the correlation integral approach and the other a more recent method using machine learning.Both methods use stellar orbit trajectories in phase space as their only input,and we create such trajectories from theoretical spherical,axisymmetric,and triaxial model galaxies.The orbits have known isolating integrals and resonances.We find that neither method is fully effective in recovering the numbers of these quantities,nor in determining the number of non-isolating integrals.From a computer performance perspective,we find the correlation integral approach to be the faster.Determining the algebraic formulae of(multiple)conserved quantities from the trajectories has not been possible due to the lack of an appropriate symbolic regression capability.Notwithstanding the shortcomings we have noted,it may be that the methods are usable as part of a trajectory analysis tool kit.Richard J.Long Shude Mao Yougang Wang 2023Research in Astronomy and Astrophysics2023,23,5:0
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