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18篇 您的检索式:作者名="Cheng Keming"
    题名 作者 年代 出处 被引量
1ELE restrains empty glumes from developing into lemmas显示文摘Although there is evident homology among reproductive organs when comparing Poaceae (grass) and eudicots, the identity of grass specific organs, such as lodicules, palea, lemma, and glumes has been the subject of a vast and largely inconclusive discussion. Here we provide some direct evidence to support the idea that the empty glumes of rice (Oryza sativa) are counterparts of lemmas. We show that the development of empty glumes is regulated by ELE (elongated empty glume), which belongs to a plant specific novel gene family. Mutations at the ELE locus cause elongated empty glumes, which mimic the lemmas and have the epidermal morphology of lemmas with four or five vascular bundles. As a nuclear-localized gene, ELE is specifically expressed at the empty glumes of immature spikelets, and its ectopic expression causes many floral development defects, including lemma-like palea, extra palea-like structures, elongated lodicules, extra stamens and stigmas. Our result suggests that empty glumes are lemmas of the sterile florets located at the lateral side of the rice spikelet, and ELE acts as a regulator restraining its growth to maintain its small size in wild-type plants.Lilan Hong Qian Qian Keming Zhu Ding Tang Zejun Huang Ling Gao Ming Li Minghong Gu Zhukuan Cheng 2010Journal of Genetics and Genomics2010,37,2:11
2Numerical and experimental investigation into hypersonic boundary layer transition induced by roughness elements显示文摘In this work, the Direct Numerical Simulation(DNS) and Oil-Film Interferometry(OFI)technique are used to investigate the hypersonic boundary layer transition induced by single and double roughness elements at Mach number 5. For single roughness, the DNS results showed that both horseshoe vortices and hairpin vortices caused by shear layer instability can affect the boundary layer instability. The generation of the near-wall unstable structure is the key point of boundary layer transition behind the roughness element. At the downstream of the roughness element, the interaction between horseshoe vortices and hairpin vortices will spread in the spanwise direction.For double roughness elements, the effect of the spacing between roughness elements on the transition is studied. It is found that the case of higher spacing between roughness elements is more effective for inducing transition than the lower one. The interaction between two adjacent roughness elements can suppress the evolution of horseshoe vortices in the downstream and trigger the instability of shear layer. Thus, the transition will be suppressed accordingly.Hao DONG Shicheng LIU Xi GENG Song LIU Liming YANG Keming CHENG 2019Chinese Journal of Aeronautics2019,32,3:6
3OsAM1 is required for leptotene-zygotene transition in rice显示文摘发生在成熟分裂的发作的事件充分没被阐明。在现在的学习, OsAM1 被基于地图的克隆在米饭(Oryza sativa L.) 识别。OsAM1, Arabidopsis SWI1 的一个相当或相同的事物和玉米 AM1,与一个卷卷领域把蛋白质编码为它的中央区域。在 Osam1 异种,花粉母亲房间在 leptotene 被逮捕,证明 OsAM1 为 leptotene-zygotene 转变被要求。Immunocytological 分析表明 OsAM1 在早前期作为 foci 存在我 meiocytes。很微弱的 OsREC8 foci 在 Osam1 异种坚持了,显示 OsAM1 没为 OsREC8 的起始的 meiotic 招募被要求。当 OsAM1 不在时,包括 PAIR2, ZEP1 和 OsMER3,许多另外的批评 meiotic 部件不能正确地被安装到染色体上。在 pair2, Osmer3 和 zep1 异种,相反, OsAM1 能通常被装载,建议 OsAM1 起造在成熟分裂的开始的合适的染色体结构里的一个基本作用。Lixiao Che Ding Tang Kejian Wang Mo Wang Keming Zhu Hengxiu Yu Minghong Gu Zhukuan Cheng 2011Cell Research2011,21,4:4
4Discovery and its geological significance of the mantle- derived helium in the inclusions of the Ordovician oil-bearing reservoir rocks in the Huanghua depression,China显示文摘The values of the helium isotopes in the inclusions of the Ordovician reservoir rocks in the Kongxi buried hill belt in the Huanghua depression were first measured and the source of helium and its geological significance were investigated in comparison with those of the helium isotopes in the conclusions in the Ordovician rocks in the Ordos basin and the Tarim basin. The input of the mantle-derived helium into the inclusions in the carbonate reservoir rocks was found from the Konggu 3 well, the Konggu 4 well, and the Konggu 7 well in the Kongxi buried hill belt. The 3He/4He and R/Ra in the conclusions in the Ordovician oil-bearing reservoir rocks in the Konggu 7 well average 2.54×10-6(3) (sample quantity, the same below) and 1.82(3), respectively. The percent of the mantle-derived helium in the inclusions of the reservoir rocks in the Konggu 7 well reaches up to an average of 23.0%(3). The age of the contribution of the mantle-derived helium to the inclusions in the Kongxi buried hill belt is in the Late Triassic or the Early Tertiary. The finding of the mantle-derived helium shows that the interaction of the deep crust with mantle and the activity of deep faults occurred, the terrestrial heat flow value was high, and mantle-derived inorganic gas pools might be formed in the Kongxi buried hill belt. The finding of the mantle-derived helium in the inclusions of oil-bearing reservoir rocks also provides a new way for researching the activity of mantle-derived matter and its associated geological problems.ZHANG Xiaobao XU Yongchang SUN Mingliang CHENG Keming LIU Wenhui LI Xiufen MA Liyuan 2004Science China Earth Sciences2004,47,1:4
5Experimental investigation of influence of strake wings on self-induced roll motion at high angles of attack显示文摘The modern high performance air vehicles are required to have extreme maneuverability,which includes the ability of controlled maneuvers at high angle of attack. However, the nonlinear and unsteady aerodynamic phenomena, such as flow separation, vortices interaction, and vortices breaking down, will occur during the flight at high angle of attack, which could induce the uncommanded motions for the air vehicles. For the high maneuverable and agile air missile, the nonlinear roll motions would occur at the high angle of attack. The present work is focused on the selfinduced nonlinear roll motion for a missile configuration and discusses the influence of the strake wings on the roll motion according to the results from free-to-roll test and PIV measurement using the models assembled with different strake wings at a = 60°. The free-to-roll results show that the model with whole strake wings(baseline), the model assembled with three strake wings(Case A)and the model assembled with two opposite strake wings(Case C) experience the spinning, while the model assembled with two adjacent strake wings(Case B), the model assembled with one strake wing(Case D) and the model with no strake wing(Case E) trim or slightly vibrate at a certain '×'rolling angle, which mean that the rolling stability can be improved by dismantling certain strake wings. The flow field results from PIV measurement show that the leeward asymmetric vortices are induced by the windward strake wings. The vortices would interact the strake wings and induce crossflow on the downstream fins to degrade the rolling stability of the model. This could be the main reason for the self-induced roll motion of the model at a = 60°.Geng Xi Shi Zhiwei Cheng Keming 2016Chinese Journal of Aeronautics2016,29,6:3
6Drag Reduction Effect for Hypersonic Lifting-Body Vehicle with Counterflowing Jet显示文摘This study takes the novel approach of using a counterflowing jet positioned on the nose of a lifting-body vehicle to explore its drag reduction effect at a range of angles of attack.Numerical studies are conducted at a freestream Mach number of 8 in standard atmospheric conditions corresponding to the altitude of 40 km.The effects of jet pressure ratio and flying angles of attack on drag reduction of the model are systematically investigated.Considering the reverse thrust generated from the counterflowing jet,the drag on the nose at hypersonic speeds could be reduced up to 66%.The maximum lift-to-drag ratio of the model is obtained at 6°;meanwhile,the counterflowing jet produces a drag reduction of 8.8%for the whole model.In addition to the nose,the counterflowing jet influences the drag by increasing the pressure drag of the model and reducing the skin friction drag of the first cone within 8°.The results show that the potential of the counterflowing jet as a means of active flow control for drag reduction is significant in the engineering application on hypersonic lifting-body vehicles.Dong Hao Deng Fan Xie Feng Geng Xi Cheng Keming 2018Transactions of Nanjing University of Aeronautics and Astronautics2018,35,5:2
7MXene-GaN van der Waals metal-semiconductor junctions for high performance multiple quantum well photodetectors显示文摘A MXene-GaN-MXene based multiple quantum well photodetector was prepared on patterned sapphire substrate by facile drop casting.The use of MXene electrodes improves the responsivity and reduces dark current,compared with traditional Metal-Semiconductor-Metal(MSM)photodetectors using Cr/Au electrodes.Dark current of the device using MXene-GaN van der Waals junctions is reduced by three orders of magnitude and its noise spectral intensity shows distinct improvement compared with the traditional Cr/Au–GaN–Cr/Au MSM photodetector.The improved device performance is attributed to low-defect MXene-GaN van der Waals interfaces.Thanks to the high quality MXene-GaN interfaces,it is possible to verify that the patterned substrate can locally improve both light extraction and photocurrent collection.The measured responsivity and specific detectivity reach as high as 64.6 A/W and 1.93×1012 Jones,respectively,making it a potential candidate for underwater optical detection and communication.The simple fabrication of MXene-GaN-MXene photodetectors spearheaded the way to high performance photodetection by combining the advantages of emerging 2D MXene materials with the conventional III-V materials.Lingzhi Luo Yixuan Huang Keming Cheng Abdullah Alhassan Mahdi Alqahtani Libin Tang Zhiming Wang Jiang Wu 2021Light(Science & Applications)2021,10,10:1
8Expulsion and primary migration of the oil derived from coal显示文摘Zhao Changyi Cheng Keming 1998Science in China: Series D1998,41,4:1
9Sinusoidal electromagnetic field stimulates rat osteoblast dif- ferentiation and maturation via activation of NO-cGMP-PKGpathway 显示文摘CHENG Guozheng ZHAI Yuankun CHEN Keming 2011Nitric Oxide2011,25,3:1
10Preparation and Properties of Polyacrylamide/Sodium Alginate Hydrogel and the Effect of Fe^(3+)Adsorption on Its Mechanical Performance显示文摘The preparation and application of functional hydrogels based on natural polysaccharides have always been a hot research topic.In this study,using acrylamide(AM)monomer,N,N'-methylene bisacrylamide(MBA)as crosslinking agent,potassium persulfate(K2S2O8)as initiator,in the presence of natural polysaccharide sodium alginate(SA),the PAM/SA hydrogel was prepared by free radical polymerization.Fourier transform infrared spectroscopy(FT-IR),swelling performance tests,scanning electron microscope(SEM),thermogravimetric analysis(TGA),UV-visible spectrophotometer,mechanical property measurements were carried out to analyze the composition,morphology,and performance of the hydrogels.The swelling behavior,dye adsorption performance,and the mechanical properties of PAM/SA hydrogels before and after Fe^(3+)adsorption were studied.The experimental results showed that the introduction of SA with 4.7%,7.8%,and 10.3%effectively improved the mechanical and dye adsorption properties of PAM composite hydrogels.The adsorption capacity of PAM/4.7%SA and PAM/10.3%SA hydrogels at equilibrium can reach 40.01 and 44.02 mg/g for methylene blue,which is higher than the value 13.58 mg/g of pure PAM hydrogel.The compressive strength of pure PAM hydrogel is 0.124 MPa.When the SA content is 4.7%,7.8%,and 10.3%,the compressive strength of the PAM/SA hydrogel was corresponding to 0.130 MPa,0.134 MPa,and 0.152 MPa,respectively.Fe^(3+)was introduced into the PAM/SA hydrogels,and PAM/SA/Fe^(3+)double-network hydrogels with excellent mechanical properties could be prepared by adjusting the SA content(4.7%,7.8%,and 10.3%),soaking time(1 h,2 h,3 h,4 h,5 h,6 h),and Fe^(3+)concentration(4.76%,7.41%,9.09%,and 13.04%).Under the same Fe^(3+)concentration of 9.09%and adsorption time of 4 h,the compressive strengths of the PAM/4.7%SA,PAM/7.8%SA,and PAM/10.3%SA hydrogels could reach 0.354 MPa,0.767 MPa,and 0.778 MPa,respectively.Zheng Cao Yang Zhang Keming Luo Yinqiu Wu Hongxin Gao Junfeng Cheng Chunlin Liu Guoliang Tao Qingbao Guan Lei Zhang 2021Journal of Renewable Materials2021,9,8:1
11ERECT PANICLE2 Encodes a Novel Protein That Regulates Panicle Erectness in Indica Rice显示文摘Zhu Keming Tang Ding Yan Changjie Chi Zhengchang Yu Hengxiu Chen Jianmin Liang Jiansheng Gu Minghong Cheng Zhukuan 2010Genetics2010,,2:1
12AN ADAPTIVE COLOR PLANE INTERPOLATION METHOD BASED ON EDGE DETECTION显示文摘In this letter, an adaptive interpolation algorithm based on edge detection is proposed. With this algorithm, all the missing green values can be reconstructed in Bayer pattern image by using edge detection interpolation method. Reconstructed images composed of green pixels are classified according to the high frequency components in image, and the threshold T needed for all kinds of green images in the edge detection is determined through experiments. The edge detection is carried out based on the one Dimensional (1D) gradient operator. If the gradient value is greater than T, this pixel is located on the edge; otherwise the pixel is in the smooth area of the image. Finally, the simple bilinear interpolation is used for the smooth area while the Laplacian interpolation with the second-order correction term is adopted to reconstruct the other red/blue values on the edge. This algorithm resolves effectively the conflicts between reconstructing high quality color image and reducing computational complexity, and thus largely enhances the processing speed for the reconstructed color image.Cheng Yongqiang Xie Keming Zhou Yingfeng Liu Yanlong 2007Journal of Electronics(China)2007,24,2:1
13Oblique shock train motion based on schlieren image processing显示文摘In this paper,shock train motion in a Mach number 2.7 duct is studied experimentally,and large numbers of schlieren images are obtained by a high-speed camera.An image processing method based on Maximum Correlation Detection(MCD)is proposed to detect shock train motion from the schlieren images,based on which the key structures,e.g.,separation positions and separation shock angles on the top and bottom walls,can be analysed in detail.The oscillations of the shock train are generated by rhombus and ellipse shafts at various excitation frequencies.According to the analysis of MCD results,the distributions of the frequency components of shock train oscillation generated by the two shafts are distinctly different,in which the motion generated by the ellipse shaft is much smoother;shock train motion is mainly characterized by the oscillation of separation position while the separation shock strength is not so sensitive to downstream disturbance;there is a hysteresis loop relation between the downstream pressure and separation position.Longsheng XUE Chuan CHENG Chengpeng WANG Lantian ZHANG Kang LI Keming CHENG 2023Chinese Journal of Aeronautics2023,36,3:0
14Contributors and potential of hydrocarbon generation of source rocks by solid-state ^(13)C NMR spectroscopy显示文摘SOLID-STATE 13C nuclear magnetic resonance (NMR) technique is an effective method to study the texture of material. Under the condition of high magnetic field (400 MHz) and by the application of cross polarization, magic angle spinning (CP/MAS), total sideband suppression (TOSS), etc., the content of different textural carbons in kerogen has been quantitatively analyzed by the solid-state 13C NMR spectroscopy of a series of kerogen of thermal simulation samples with Ro value ranging from 0.64% to 1.76%. The results show thatWANGZhaoyun, ZHAO Changyi, CHENG Keming and LU Qinghua1. Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China:2. University of Petroleum, Beijing, 100083 China 1997Chinese Science Bulletin1997,42,6:0
15Three vortex motion in the slightly viscous flow显示文摘The dynamics of three vortices moving in an ideal fluid in a plane can be expressed in Hamiltonian form. However, when viscosity can not be ignored, the system of point vortices has not this delicious structure. This investigation focuses on the viscosity effect on the motion of three vortices. Since the viscous diffusion of vortices is simulated by Brownian motion, the equations of intervortical distances are obtained by Ito formula. These equations show that there exist two viscosity effects on intervortical distances: stable expansion and random impulse. Furthermore, via employing the asymptotic solution to these equations, these two viscous effects have been shown to destroy the self-similar process of collapse and make it into a new configuration, which is similar to the near collapse in the ideal case.ZHU Hao & CHENG KeMing College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China 2010Science China(Physics,Mechanics & Astronomy)2010,53,4:0
16The model of hydrocarbon generation and evolution for coal and macerals in the Tuha Basin显示文摘By means of Py-GC, 13C NMR and fluorescent analysis, the properties of hydrocarbon generation of macerals are determined, and the evolution model of hydrocarbon generation is established for macerals and coal of the Tuha Basin. There are two stages of oil generation for the coal of the Tuha Basin, whose R+o values are 0.40-0.80 and 0.90-1.20 respectively.Changyi Zhao Keming Cheng 1998Chinese Science Bulletin1998,43,21:0
17The internal efficiency in higher education:An analysis based on economies of scope显示文摘已有的关于中国高校效率的文献多集中于研究高校的规模(规模经济),更深层次的关于高校内部运行效率尤其是内部产出组合效率(范围经济)的研究寥寥无几。中国高校的教学和科研资源是否互补、本科生教育和研究生培养资源是否共享等重大问题缺少理论探讨和经验研究。在高等教育资源稀缺的现实背景下,研究高校范围经济对于实现中国高等教育内涵式发展意义重大。使用多产出成本函数,并利用教育部直属高校数据对中国高校的本科生教育、研究生培养和科研活动之间的资源互补状况进行的研究发现:中国高校提供这些产出时未充分共享资源,其中研究生的培养较为孤立,范围不经济程度较高;在考虑中国高校的教学和科研质量后,高校产出间的资源不共享程度更为加大。反思范围不经济的原因,主要在于中国高校的设备、师资、图书的条块分割和内部管理体制的交叉重叠,同时,现行的研究生培养方式导致了研究生培养的相对割裂。因此,有关部门在制定高等教育管理政策时应充分考虑到高校内部资源的共享和互补,还应重视学校的类型和办学地点对高校内部资源配置的影响。CHENG Gang WU Keming 2008Frontiers of Education in China2008,3,1:0
18An integration method based on a novel combined flow for aerodynamic configuration of strutjet engine显示文摘In this paper a novel design method of aerodynamic configuration is proposed to integrate forebody,strut and inlet for strutjet engine,and a model at design point of Mach number6 is generated to investigate the aerodynamic performance by both simulations and experiments.The basic flow field employed by proposed method is a combined flow named IBB,which is combined by Internal Conical Flow A(ICFA),truncated Busemann flow I(BI)for external section,and truncated Busemann flow II(BII)for internal section.The model configuration is generated by streamline tracing method from basic flow field,in which the forebody section is traced from ICFA and BI flows,and the inlet as well as strut section is traced from BII flow.The simulations in Mach number 4,5,and 6 demonstrate uniform starting flow fields with relatively high total pressure recovery,which agree well with experiments in wind tunnel.Additionally,in low Mach number cases,this inlet could start at Mach number 3 while it is unstarted at Mach number 2.7;in high Mach number cases,a uniform flow could still exist in Mach number 6.5 while a relatively strong shock wave boundary layer interaction is found in cowl area of Mach number 7 case,indicating the inlet designed by proposed method works in a relatively wide Mach number range.Longsheng XUE Chuan CHENG Chengpeng WANG Keming CHENG 2021Chinese Journal of Aeronautics2021,34,9:0
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