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38篇 您的检索式:作者名="Yunjun Zhang"
    题名 作者 年代 出处 被引量
1Artificially triggered lightning and its characteristic discharge parameters in two severe thunderstorms显示文摘The lightning-induced-damages in the mid-latitude regions are usually caused during severe thunder-storms. But the discharge parameters of natural lightning are difficult to be measured. Five lightning flashes have been artificially triggered with the rocket-wire technique during the passage of two severe thunderstorms. The discharge current and close electric field of return stroke in artificially triggered lightning have been obtained in microsecond time resolution by using current measuring systems and electric field change sensors. The results show that the five triggered lightning flashes include 1 to 10 return strokes, and the average return stroke current is 11.9 kA with a maximum of 21.0 kA and a mini-mum of 6.6 kA, similar to the subsequent return strokes in natural lightning. The half peak width of the current waveform is 39 μs, which is much larger than the usual result. The peak current of stroke Ip (kA) and the neutralized charge Q(C) has a relationship of Ip = 18.5Q0.65. The radiation field of return stroke is 5.9 kV·m-1 and 0.39 kV·m-1 at 60 m and 550 m, respectively. The radiation field decreases as r -1.119 with increase of horizontal distance r from the discharge channel. Based on the well-accepted transmission line model, the speed of return stroke is estimated to be about 1.4×108 m·s-1, with a variation range of (1.1―1.6)×108 m·s-1. Because of the similarities of the triggered lightning and natural lightning, the results in this article can be used in the protection design of natural lightning.QIE XiuShu ZHANG QiLin ZHOU YunJun FENG GuiLi ZHANG TingLong YANG Jing KONG XiangZhen XIAO QingFu WU ShuJun 2007Science China Earth Sciences2007,50,8:16
2QTG-Seq Accelerates QTL Fine Mapping through QTL Partitioning and Whole-Genome Sequencing of Bulked Segregant Samples显示文摘Deciphering the genetic mechanisms underlying agronomic traits is of great importance for crop improvement. Most of these traits are controlled by multiple quantitative trait loci (QTLs), and identifying the underlying genes by conventional QTL fine-mapping is time-consuming and labor-intensive. Here, we devised a new method, named quantitative trait gene sequencing (QTG-seq), to accelerate QTL fine-mapping. QTGseq combines QTL partitioning to convert a quantitative trait into a near-qualitative trait, sequencing of bulked segregant pools from a large segregating population, and the use of a robust new algorithm for identifying candidate genes. Using QTG-seq, we fine-mapped a plant-height QTL in maize (Zea mays L.), qPH7, to a 300-kb genomic interval and verified that a gene encoding an NF-YC transcription factor was the functional gene. Functional analysis suggested that qPH7-encoding protein might influence plant height by interacting with a CO-like protein and an AP2 domain-containing protein. Selection footprint ana卜 ysis indicated that qPH7 was subject to strong selection during maize improvement. In summary, QTG-seq provides an efficient method for QTL fine-mapping in the era of “big data'.Hongwei Zhang Xi Wang Qingchun Pan Pei Li Yunjun Liu Xiaoduo Lu Wanshun Zhong Minqi Li Linqian Han Juan Li Pingxi Wang Dongdong Li Yan Liu Qing Li Fang Yang Yuan-Ming Zhang Guoying Wang Lin Li 2019Molecular Plant2019,12,3:13
3Minor alloying behavior in bulk metallic glasses and high-entropy alloys显示文摘The effect of minor alloying on several bulk metallic glasses and high-entropy al-loys was studied. It was found that minor Nb addition can optimize the interface structure between the W fiber and the Zr-based bulk metallic glass in the compos-ites,and improve the mechanical properties. Minor Y addition can destabilize the crystalline phases by inducing lattice distortion as a result to improve the glass-forming ability,and the lattice distortion energy is closely related to the effi-ciency of space filling of the competing crystalline phases. A long-period ordered structure can precipitate in the Mg-based bulk metallic glass by yttrium alloying. For the high-entropy alloys,solid solution can be formed by alloying,and its me-chanical properties can be comparable to most of the bulk metallic glasses.ZHANG Yong ZHOU YunJun HUI XiDong WANG MeiLing CHEN GuoLiang 2008Science China(Physics,Mechanics & Astronomy)2008,51,4:10
4Effect of component substitution on the microstructure and mechanical properties of MCoCrFeNiTi_x (M = Cu, Al) solid-solution alloys显示文摘MCoCrFeNiTix (M = Cu, Al; x: molar ratio, x = 0, 0.5) alloys were prepared using the new alloy-design strategy of equal-atomic ratio and high entropy. By the component substitution of Al for Cu, the microstructure changes from the face-centered cubic solid solution of original CuCoCrFeNiTix alloys to the body-centered cubic solid solution of AlCoCrFeNiTix alloys. Compared with original CuCoCrFeNiTix alloys, AlCoCrFeNiTix alloys keep the similar good ductility and simultaneously possess a much higher compressive strength, which are even supe- rior to most of the reported high-strength alloys like bulk metallic glasses.ZHOU Yunjun ZHANG Yong WANG Xuefei WANG Yanli CHEN Guoliang 2008Rare Metals2008,27,6:5
5The U6 Biogenesis-Like I Plays an Important Role in Maize Kernel and Seedling Development by Affecting the 3' End Processing of U6 snRNA显示文摘Jiankun Li Junjie Fu Yan Chen Kaijian Fan Cheng He Zhiqiang Zhang Li Li Yunjun Liu Jun Zheng Dongtao Ren Guoying Wang 2017Molecular Plant2017,10,3:5
6A Review of Atmospheric Electricity Research in China显示文摘The importance of atmospheric electricity research has been increasingly recognized in recent decades. Research on atmospheric electricity has been actively conducted since the 1980 s in China. Lightning physics and its effects, as important branches of atmospheric electricity, have received more attention because of their significance both in scientific research and lightning protection applications. This paper reviews atmospheric electricity research based primarily on ground-based field experiments at different regions in China in the last decade. The results described in this review include physics and effects of lightning, rocket-triggered lightning and its physical processes of discharge, thunderstorm electricity on the Tibetan Plateau and its surrounding areas, lightning activity associated with severe convective storms, the effect and response of lightning to climate change, numerical simulation of thunderstorm electrification and lightning discharge, lightning detection and location techniques, and transient luminous events above thunderstorms.QIE Xiushu ZHANG Yijun YUAN Tie ZHANG Qilin ZHANG Tinglong ZHU Baoyou LU Weitao MA Ming YANG Jing ZHOU Yunjun FENG Guili 2015Advances in Atmospheric Sciences2015,32,2:5
7Apparent diffusion coefficient evaluation for secondary changes in the cerebellum of rats after middle cerebral artery occlusion显示文摘Supratentorial cerebral infarction can cause functional inhibition of remote regions such as the cerebellum,which may be relevant to diaschisis.This phenomenon is often analyzed using positron emission tomography and single photon emission CT.However,these methods are expensive and radioactive.Thus,the present study quantified the changes of infarction core and remote regions after unilateral middle cerebral artery occlusion using apparent diffusion coefficient values.Diffusion-weighted imaging showed that the area of infarction core gradually increased to involve the cerebral cortex with increasing infarction time.Diffusion weighted imaging signals were initially increased and then stabilized by 24 hours.With increasing infarction time,the apparent diffusion coefficient value in the infarction core and remote bilateral cerebellum both gradually decreased,and then slightly increased 3–24 hours after infarction.Apparent diffusion coefficient values at remote regions(cerebellum)varied along with the change of supratentorial infarction core,suggesting that the phenomenon of diaschisis existed at the remote regions.Thus,apparent diffusion coefficient values and diffusion weighted imaging can be used to detect early diaschisis.Yunjun Yang Lingyun Gao Jun Fu Jun Zhang Yuxin Li Bo Yin Weijian Chen Daoying Geng 2013Neural Regeneration Research2013,8,31:3
8Significance of vulnerability assessment in establishment of Hainan provincal disaster medical system显示文摘Hainan is an island province in south China with a high frequency of unconventional emergencies due to its special geographic location and national military defense role.Given the limited transportation route from Hainan to the outside world,self-rescue is more important to Hainan Province than other provinces in China and it is therefore imperative to establish an independent, scientific as well as efficient provincal disaster medical system in Hainan.The regulatory role for vulnerability analysis/assessment has been demonstrated in establisment of disaster medical system in varoius countries and or regions.In this paper,we attempt to describe/propose how to adopt vulnerability assessment through mathematical modeling of major biophysical social vulnerability factors to establish an independent,scientific,effieicnt and comprehensive provincial disaster medical system in Hainan.Min Li Chuanzhu Lu Wei Son Junhong Miao Yipeng Ding Longhe Li Leilei Zhang Nin Zhao Bijiang Hu Yunjun Zhang 2011Asian Pacific Journal of Tropical Medicine2011,4,8:2
9Land use and land cover classification using Chinese GF-2 multispectral data in a region of the North China Plain显示文摘The newly launched GF-2 satellite is now the most advanced civil satellite in China to collect high spatial resolution remote sensing data.This study investigated the capability and strategy of GF?2 multispectral data for land use and land cover (LULC) classification in a region of the North China Plain.The pixel-based and object-based classifications using maximum likelihood (MLC) and support vector machine (SVM) classifiers were evaluated to determine the classification strategy that was suitable for GF?2 multispectral data.The validation results indicated that GF-2 multispectral data achieved satisfactory LULC classification performance,and object-based classification using the SVM classifier achieved the best classification accuracy with an overall classification accuracy of 94.33% and kappa coefficient of 0.911.Therefore,considering the LULC classification performance and data characteristics,GF-2 satellite data could serve as a valuable and reliable high-resolution data source for land surface monitoring.Future works should focus on improving LULC classification accuracy by exploring more classification features and exploring the potential applications of GF-2 data in related applications.Kun JIA Jingcan LIU Yixuan TU Qiangzi LI Zhiwei SUN Xiangqin WEI Yunjun YAO Xiaotong ZHANG 2019Frontiers of Earth Science2019,13,2:2
10Fabrication and thermal decomposition of glycidyl azide polymer modified nitrocellulose double base propellants显示文摘Glycidyl azide polymer(GAP) with the advantages of non-volatility and excellent thermal stability is a candidate as a replacement for nitroglycerine(NG) in a double base propellant. The GAP-NC double base propellants were formulated with GAP and nitrocellulose(NC) fibers. Tensile test and SEM characterization indicated that GAP-NC propellants had a homogeneous structure. Thermogravimetric analysis of GAP-NC propellants revealed that the onset decomposition temperature reached a high level ranging from 192.9 to 194.6 °C, which indicated that the substitution of NG with GAP contributed to the safe storage and process operations for double base propellant. The result analysis of decomposition products of GAP-NC propellants showed that the main gas decomposition products of the propellants were NO, NO_2, CO, CO_2, NH_3, CH_4, HCN, N_2, CH_2O and C_2H_4O. The thermal decomposition process of the specimens was proposed.Benbo Zhao Tianfu Zhang Zhen Ge Yunjun Luo 2016Science China Chemistry2016,59,4:2
11Homology Modeling of CrylAc Toxin-binding Alkaline Phosphatase Receptor from Helicoverpa armigera and Its Functional Interpretation显示文摘Shan, Shiping Xia, Liqiu Ding, Xuezhi Zhang, Youming Hu, Shengbiao Sun, Yunjun Yu, Ziquan Han, Lizhen 2011Chinese Journal of Chemistry2011,29,3:1
12Ag and Ag/N2 plasma modification of polyethylene for the enhancement of antibacterial properties and cell growth/proliferation 显示文摘Wei Zhang Yunjun Luo Huaiyu Wang 2008Aeta Biomaterialia2008,4,6:1
13Fractional vegetation cover estimation in heterogeneous areas by combining a radiative transfer model and a dynamic vegetation model显示文摘A fractional vegetation cover(FVC)estimation method incorporating a vegetation growth model and a radiative transfer model was previously developed,which was suitable for FVC estimation in homogeneous areas because the finer-resolution pixels corresponding to one coarseresolution FVC pixel were all assumed to have the same vegetation growth model.However,this assumption does not hold over heterogeneous areas,meaning that the method cannot be applied to large regions.Therefore,this study proposes a finer spatial resolution FVC estimation method applicable to heterogeneous areas using Landsat 8 Operational Land Imager reflectance data and Global LAnd Surface Satellite(GLASS)FVC product.The FVC product was first decomposed according to the normalized difference vegetation index from the Landsat 8 OLI data.Then,independent dynamic vegetation models were built for each finer-resolution pixel.Finally,the dynamic vegetation model and a radiative transfer model were combined to estimate FVC at the Landsat 8 scale.Validation results indicated that the proposed method(R^(2)=0.7757,RMSE=0.0881)performed better than either the previous method(R^(2)=0.7038,RMSE=0.1125)or a commonly used method involving look-up table inversions of the PROSAIL model(R^(2)=0.7457,RMSE=0.1249).Yixuan Tu Kun Jia Shunlin Liang Xiangqin Wei Yunjun Yao Xiaotong Zhang 2020International Journal of Digital Earth2020,13,4:1
14显示文摘Bao Lihong Lan Yunjun Zhang Shufen 2006Polym Res2006,13,6:1
15Isolation and analysis of water stress induced genes in maize seedlings by subtraetive PCR and cDNA macroarry显示文摘Zheng Jun Zhao Junfeng Tao Yazhong Wang Jianhua Liu Yunjun Fu Junjie Jin Ying Gao Peng Zhang Jinpeng Bai Yunfeng Wang Guoying 2004Plant Molecular Biology2004,55,:1
16Lack of evolutionary changes identified in SARS-CoV-2 for the re-emerging outbreak of COVID-19 in Beijing,China显示文摘Although significant achievements have shown that the coronavirus disease 2019(COVID‐19)resurgence in Beijing,China,was initiated by contaminated frozen products and transported via cold chain transportation,international travelers with asymptomatic symptoms or false‐negative nucleic acid may have another possible transmission mode that spread the virus to Beijing.One of the key differences between these two assumptions was whether the virus actively replicated since,so far,no reports showed viruses could stop evolution in alive hosts.We studied severe acute respiratory syndrome coronavirus 2(SARS‐CoV‐2)sequences in this outbreak by a modified leaf‐dating method with the Bayes factor.The numbers of single nucleotide variants(SNVs)found in SARS‐CoV‐2 sequences were significantly lower than those called from B.1.1 records collected at the matching time worldwide(P=0.047).In addition,results of the leaf‐dating method showed ages of viruses sampled from this outbreak were earlier than their recorded dates of collection(Bayes factors>10),while control sequences(selected randomly with ten replicates)showed no differences in their collection dates(Bayes factors<10).Our results which indicated that the re‐emergence of SARS‐CoV‐2 in Beijing in June 2020 was caused by a virus that exhibited a lack of evolutionary changes compared to viruses collected at the corresponding time,provided evolutionary evidence to the contaminated imported frozen food should be responsible for the reappearance of COVID‐19 cases in Beijing.The method developed here might also be helpful to provide the very first clues for potential sources of COVID‐19 cases in the future.Yang Li Yunjun Zhang Mifang Liang Yi Zhang Xuejun Maa Yong Zhang Xiaohua Zhou 2022Biosafety and Health2022,4,1:1
17Overexpression of a novel crylle gene confers resistance to CrylAc-resistant cotton bollworm in transgenic lines of maize显示文摘Zhang Yuwen Liu Yunjun Ren Yuan 2013Plant Cell Tissue and Organ Culture2013,115,:1
18Aliphatic anionic polyurethane microe- mulsion leather filling - retanning agent 显示文摘Bao Lihong Lan Yunjun Zhang Shufen 2007Journal of the Science of Leather Technologists and Chemists2007,91,:1
19Isolation and analysis of water stress induced genes in maize seedlings by subtractive PCR and cDNA macroarray显示文摘Jun Zheng Jinfeng Zhao Yazhong Tao Jianhua Wang Yunjun Liu Junjie Fu Ying Jin Peng Gao Jinpeng Zhang Yunfeng Bai Guoying Wang 2004Plant Molecular Biology2004,,6:1
20MODIS -driven estimation of terrestrial latent heat flux in China based on a modified Priestley–Taylor algorithm显示文摘Yunjun Yao Shunlin Liang Jie Cheng Shaomin Liu Joshua B. Fisher Xudong Zhang Kun Jia Xiang Zhao Qiming Qin Bin Zhao Shijie Han Guangsheng Zhou Guoyi Zhou Yuelin Li Shaohua Zhao 2012Agricultural and Forest Meteorology2012,,:1
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