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Search Results: 1 - 10 of 90549 matches for " HU Yu-kun "
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Biorthonormal Matrix-Product-State Analysis for Non-Hermitian Transfer-Matrix Renormalization-Group in the Thermodynamic Limit
Yu-Kun Huang
Statistics , 2011, DOI: 10.1088/1742-5468/2011/07/P07003
Abstract: We give a thorough Biorthonormal Matrix-Product-State (BMPS) analysis of the Transfer-Matrix Renormalization-Group (TMRG) for non-Hermitian matrices in the thermodynamic limit. The BMPS is built on a dual series of reduced biorthonormal bases for the left and right Perron states of a non-Hermitian matrix. We propose two alternative infinite-size Biorthonormal TMRG (iBTMRG) algorithms and compare their numerical performance in both finite and infinite systems. We show that both iBTMRGs produce a dual infinite-BMPS (iBMPS) which are translationally invariant in the thermodynamic limit. We also develop an efficient wave function transformation of the iBTMRG, an analogy of McCulloch in the infinite-DMRG [arXiv:0804.2509 (2008)], to predict the wave function as the lattice size is increased. The resulting iBMPS allows for probing bulk properties of the system in the thermodynamic limit without boundary effects and allows for reducing the computational cost to be independent of the lattice size, which are illustrated by calculating the magnetization as a function of the temperature and the critical spin-spin correlation in the thermodynamic limit for a 2D classical Ising model.
A Strong Tracking Particle Filter with Application to Fault Prediction
强跟踪粒子滤波算法及其在故障预报中的应用

HU Chang-Hua,ZHANG Qi,QIAO Yu-Kun,
胡昌华
,张琪,乔玉坤

自动化学报 , 2008,
Abstract: Particle degeneracy and its poor ability to track saltatory states are two main problems when a particle filter is applied to fault prediction.The sequential importance re-sampling particle filter can abate the influence of particle degeneracy but will easily lead to another problem-sample impoverishment.The extended particle filter can resolve the problem of particle degeneracy to a certain extent but can not track the saltatory state.A strong tracking particle filter is put forward by introducing a strong tracking filter into a particle filter to resolve the above problems,in which the strong tracking filter is used to update particles and produce importance densities.As a result, the problems of particle degeneracy and sample impoverishment are ameliorated,and the tracking ability is improved. Simulation results demonstrate that the strong tracking particle filter is feasible and system fault can be predicted in time and correctly.
The Biomass of Different Species Communities of Alpine Meadow in Bayinbulak Region
巴音布鲁克高寒草甸不同群落类型的生物量

HU Yu-kun,LI Kai-hui,WANG Xin,FAN Yong-gang,ZHANG Xiao-yan,
胡玉昆
,李凯辉,王鑫,范永刚,张晓艳,吾买尔·吾守,HU Yu-kun,LI Kai-hui,WANG Xin,FAN Yong-gang,ZHANG Xiao-yan,Wumaier·wushou

资源科学 , 2007,
Abstract: 生物量是生态系统获取能量能力的集中体现, 对生态系统结构的形成具有十分重要的影响。草地生态系统是陆地生态系统分布最广的生态类型之一, 在全球变化中的作用非常重要。本文以新疆天山中部的巴音布鲁克高寒草甸为研究对象, 选取了黑花苔草(Carex melantha)、鬼见愁锦鸡儿(Caragana jubata)和线叶嵩草(Kobresia capillifolia) 3种典型的群落类型,开展了生物量研究。结果表明:①黑花苔草群落盖度最大, 为100%, 物种数最低, 每平方米拥有植物8种~11种。鬼见愁锦鸡儿群落盖度次之, 为86.14%, 物种组成丰富, 每平方米拥有植物12种~15种。线叶嵩草群落盖度最低, 55.7%, 每平方米拥有植物13种~16种;②各群落内部的物种丰富度与地上生物量之间无显著关系, 而群落间表现出负相关, 差异极显著;③黑花苔草群落的地下生物量最大, 线叶嵩草群落次之, 鬼见愁锦鸡儿群落最低, 分别为13 608.8g/m2、6 097.8g/m2和2 554.74g/m2;④3种群落的地下生物量呈现出“T”形分布的模式, 且集中分布在0cm~10cm的土层中;⑤3种群落的地上生物量与土壤含水量呈极显著正相关, 地下生物量受相对湿度影响较大,二者也呈极显著正相关。
松辽盆地北部双城地区扶余油层层序地层格架与沉积体系展布
Sequence Stratigraphy Framework and Depositional System Distribution of Fuyu Reservoir in Shuangcheng Area, Northern Songliao Basin

邓庆杰,胡明毅,胡忠贵,吴玉坤
DENG Qing-jie
,HU Ming-yi,HU Zhong-gui,WU Yu-kun

- , 2015,
Abstract: 摘要: 通过多口岩心精细观察,结合135口探井资料分析,识别出各种沉积微相标志,确定了松辽盆地北部双城地区扶余油层主要为曲流河-浅水三角洲沉积体系,进一步划分为5种亚相、11种微相。以高分辨率层序地层学理论为指导,通过岩-电结合、井-震结合等技术手段,识别层序界面,将其详细划分为2个长期基准面半旋回、7个中期基准面旋回,建立等时层序地层格架。以中期基准面旋回为编图单元,结合地震属性综合分析,编制了不同时期岩相古地理图,分析其演化规律,建立沉积模式,研究表明:研究区扶余油层主要经历了2个大的演化阶段:Q3-sq1—Q4-sq1时期,由浅水三角洲平原沉积逐渐向曲流河沉积转换;Q4-sq2—Q4-sq3时期,由曲流河沉积向浅水三角洲平原、前缘沉积转换,反映水体先变浅又逐渐变深的一次湖退-湖侵沉积过程,为近期油气勘探提供重要的指导意义。
Abstract: Based on core observation, combined with 135 exploration wells data, various sedimentary microfacies signs were identified. All these showed that Fuyu reservoir mainly developed meandering river-shallow water delta depositional system in Shuangcheng area, Northern Songliao Basin, furtherly divided into 5 subfacies and 11 microfacies. With the guidance of high resolution sequence stratigraphy, using the technologies of rock-electric combination, well-seismic combination and so on, several sequence boundaries were identified. Fuyu reservoir can be divided into 2 long-term base level hemicycles and 7 middle-term base level cycles, and in this way, isochronous sequence stratigraphy framework has been established. Taking middle-term base level cycle as compilation unit, combined with the analysis of seismic attribute, lithofacies paleographic maps in different period were compiled and depositional model was established. Research show that Fuyu reservoir in study area mainly experienced two evolutionary stages: during the period of Q3-sq1—Q4-sq1, shallow delta plain gradually converted to meandering river; while during the period of Q4-sq2—Q4-sq3, meandering river depositional system converted to delta plain subfaceis and delta front subfacies. All these reflected a lake retreat-lake transgression depositional process during which the sedimentary water is firstly shallowing then gradually deepening. The results of above studies provide an important guidance for recent oil and gas exploration
Distribution and rDNA-ITS sequence analysis of Epichlo endophyte symbiosis with Achnatherum sibiricum in mid-and eastern Inner Mongolia Steppe
内蒙古中东部草原羽茅Epichlo属内生真菌的分布及rDNA-ITS序列系统发育

ZHANG Xin,LI Yi,WEI Yu-Kun,WANG Yin-Hu,LIN Feng,REN An-Zhi,GAO Yu-Bao,
张欣
,李熠,魏宇昆,王银华,林枫,任安芝,高玉葆

生态学报 , 2007,
Abstract: 对内蒙古中东部地区分布的羽茅6个地理种群的染菌率进行了调查,采集种子并从中分离得到不同形态型的内生真菌,选取其中的19株进行rDNA-ITS片段的扩增、克隆、测序和系统发育分析。结果表明:(1)6个样地羽茅种群内生真菌感染率除西乌旗为96.7%外,其他5个样地均为100%,表明内生真菌侵染羽茅并非偶然现象,二者之间存在一种稳定的共生关系。(2)ITS和5.8S序列得到的N-J树显示,相对于Epichlo属的其他参考菌株,不同地理种群羽茅中的内生真菌聚为一类,形成一个具有97%支持强度的分支。由此推测,不同地理种群羽茅中的内生真菌具有相同的起源点。(3)结合形态观察结果和rDNA-ITS序列分析结果可以看出,羽茅内生真菌种群的优势种亲缘关系较近,可能起源于同一种内生真菌;但由于其地理分布广、气候差异大、群落类型差别也较大,从而造成不同地理种群内生真菌形态上的分化以及种群间明显的遗传分化和较高的遗传多样性。
Effect of root-knot nematode inoculation on rhizospheric soil pH and microbial community of cucumber (Cucumis sativus L. ) plant
根结线虫接种对黄瓜植株根际土壤pH和微生物的影响

XU Hu,RUAN Wei-Bin,GAO Yu-Bao,SONG Xiao-Yan,WEI Yu-Kun,
许 华
,阮维斌,高玉葆,宋晓艳,魏宇昆

中国生态农业学报 , 2010,
Abstract: Root-knot nematodes (RKNs) are the most destructive field pathogens of cucumber plant. This study evaluated rhizospheric soil pH and soil microbial community response to RKN inoculation. Results of the study show that aerobic bacteria, anaerobic bacteria and total bacteria number as well as bacteria/fungi (B/F) ratio gradually decline with the increasing inoculation rate. However, fungi number gradually increases with increasing inoculation rate. Both actinomyce/fungi (A/F) ratio and actinomyce number increase at an inoculation rate of 2 000 eggs per plant, but gradually decrease with increasing inoculation rate. Under RNKs inoculation, rhizospheric soil pH is significantly positively correlated with aerobic bacteria, B/F, anaerobic bacteria number, total bacteria number, actinomyce number and A/F ratio. However, rhizospheric soil pH is significantly negatively correlated with fungi number. RKNs infection apparently increases fungal population density in rhizospheric soils, implying degradation of soil quality due to RKNs infection.
Analyzing the Climatic Changes in Hebei Plain over the Last 34 Years
河北平原34年来气候变化趋势分析

ZHAO Shao-hua,YANG Yong-hui,QIU Guo-yu,FAN Tong,HU Yu-kun,
赵少华
,杨永辉,邱国玉,樊彤,胡玉昆

资源科学 , 2007,
Abstract: 基于河北平原49个气象台站的逐月气象资料,利用Hargreaves模型模拟分析了1966年~1999年共34年时间序列上河北平原的蒸散、降水和气温等气候变化。结果表明,在时间序列上的四季和年蒸散变化中,春季表现为上升趋势,其他季节和年蒸散则均呈下降趋势,其中夏季蒸散呈幂函数下降并达显著水平(P<0.05),年蒸散也表现为幂函数下降趋势,34年间蒸散的平均下降速率为7.4mm/10年。降水的变化则表现为春冬季节上升,夏秋季节下降,年变化呈线性下降趋势,下降速率为16.67mm/10年。河北平原四季和年平均气温均呈现线性增加趋势,除夏季之外,其他季节均温和年均温的增高均达极显著水平(P<0.01),年均温的增温速率为0.38℃/10年。降水的平均下降速率大于蒸散的平均下降速率,加上近年来平均气温的逐渐升高,表明34年来河北平原的气候趋向干旱化。
Sedimentary Microfacies of the First Member of Shahejie Formation in Pucheng Oilfield, Dongpu Sag of Bohaiwan Basin
渤海湾盆地东濮凹陷濮城油田沙一段沉积微相研究

ZHANG Yu-kun,HU Wang-shui,LI Xiang-ming,ZHOU Jiang-jiang,CAI Feng,
张宇焜
,胡望水,李相明,周江江,蔡峰

天然气地球科学 , 2009,
Abstract: According to the research on the core and well logging data of the first member of Shahejie Formation, this paper analyzes the sedimentary characteristics and distribution of the sedimentary microfacies of the area. Delta facies and lake facies are developed in the research area. The delta facies developed subsea river channel, mouth bar, distal bar, frontal sand sheet and predelta mud microfacies; Lake facies developed shallow\|lake beach sand, shallow\|lake sandbar and shallow\|lake mud microfacies. The sedimentary mode and the sedimentary characteristics are established on the basis of considering the macrocosmic depositional setting and the microcosmic sedimentary characteristics.
Relationships between aboveground biomass and environmental factors along an altitude gradient of alpine grassland
不同海拔梯度高寒草地地上生物量与环境因子关系

LI Kai-hui,HU Yu-kun,WANG Xin,FAN Yong-gang,WUMAIER Wu-shou,
李凯辉
,胡玉昆,王鑫,范永刚,吾买尔·吾守

应用生态学报 , 2007,
Abstract: In order to analyze the relationships between aboveground biomass and environmental factors along an altitude gradient of Bayanbulak alpine grassland on the southern slope of Tianshan Mountain, nine plots were selected, with each at 100 m interval of altitude. The results showed that Stipa purpurea and Festuca ovina communities distributed at the altitude from 2460 to 2760 m, and the aboveground biomass were 52.2-75.9 g x m(-2). Kobresia capillifolia + S. purpurea communities distributed at altitude 2860 m, and the aboveground biomass was 53.2 g x m(-2). K. capillifolia, Aichemilla tianschanica and Carex stenocarpa distributed at the altitude from 2860 to 3260 m, and the aboveground biomass was 62.1-107.4 g x m(-2). The mean relative humidity in July and August had greater effects on the aboveground biomass. Altitude had a negative correlation with the aboveground biomass of gramineous functional group, but a positive correlation with that of sedge functional group. The mean air temperature in July and August was the key factor affecting the aboveground biomass of gramineous and sedge functional groups, and the stepwise regression equations were Y = 13.467X - 97.284 and Y = 171.699 - 15.331X, respectively (X represented mean air temperature, and Y represented aboveground biomass). Altitude was negatively correlated with mean air temperature and soil pH value (P < 0.01), and positively correlated with mean relative humidity (P < 0.01) and soil available nitrogen and water content (P < 0.05).
The Emission Model of Secondary Electron in Multistage Depressed Collector CAD
多级降压收集极CAD中的二次电子发射模型

Huang Tao,Yang Zhong-hai,Jin Yong-bing,Jin Xiao-lin,Hu Quan,Qin Yu-kun,
黄桃
,杨中海,金勇兵,金晓林,胡权,秦钰昆

电子与信息学报 , 2008,
Abstract: The Multistage Depressed Collector (MDC) is widely used to improve the efficiency of microwave amplifiers. The emission of secondary electron in MDC has important influence on the efficiency. In this paper, the emission models of true secondary electron, elastic and inelastic reflected electron are discussed, and the corresponding emission ratio, angle and energy distribution are deeply analyzed. Moreover, the convergence criteria in MDC simulation is discussed, when the secondary electron are considered. The results of the analysis and discussion are used in the CAD software about MDC design, and the effects of secondary electron on the efficiency of MDC are quantitatively analyzed.
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