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Search Results: 1 - 10 of 77601 matches for " LIANG Zheng-zhao "
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NUMERICAL ANALYSIS OF PATHWAY FORMATION OF GROUNDWATER INRUSH FROM FAULTS IN COAL SEAM FLOOR
含断层煤层底板突水通道形成过程的仿真分析

LI Lian-chong,TANG Chun-an,LIANG Zheng-zhao,MA Tian-hui,ZHANG Yong-bin,
李连崇
,唐春安,梁正召,马天辉,张永彬

岩石力学与工程学报 , 2009,
Abstract: 基于对断层形态、产状要素、力学性质复杂性及断层诱发突水机制的认识,针对承压水上采煤的含断层岩体水力学模型,通过有限元数值仿真再现了含断层煤层开采底板采动裂隙形成、断层活化到突水通道形成的全过程.通过对损伤演化、应力场和渗流场的解读,揭示开采扰动及水压驱动下完整底板由隔水岩层到突水通道的演化机制.数值分析结果显示:断层本身的物理力学性质及断层的产状要素,包括断距和倾角等,对煤层底板的相对安全性都具有重要的影响.最后结合现场地质、水文地质调查及数值仿真结果对一工程实例进行突水机制分析,为承压水上采煤底板突水的机制分析及防治提供一些新的认识.
ANALYSIS OF PROBABILITY OF WATER INRUSH FROM GROUT CURTAIN BASED ON BACKGROUND STRESS FIELD AND MICROSEISMICITY
基于背景应力场与微震活动性的注浆帷幕 突水危险性评价

LIU Chao,TANG Chun-an,LI Lian-chong,LIANG Zheng-zhao,ZHANG Sheng-jun,
刘超
,唐春安,李连崇,梁正召,张省军

岩石力学与工程学报 , 2009,
Abstract: 为了研究背景应力场、微震活动规律和突水危险性之间的关系,结合张马屯铁矿注浆帷幕共同体堵水工程,运用已经建立并运行的ESG微震监测系统,圈定微破裂形成并积聚的三维空间,划分注浆帷幕共同体的突水危险区域.通过三维有限元程序MSC.PATRAN建立矿帷幕共同体的三维力学模型,模拟高水压下的背景应力场分布,得到矿帷幕共同体的应力场集中区域.二者对比结果表明:帷幕西南区域和矿体采空区两侧积聚了大量的微震定位事件,微震活动性信息较为明显;而在上述2个区域,高水压力和开采扰动使原应力场发生极大改变,出现了明显的地应力集中现象,说明应力场的扰动会诱发微破裂的萌生、发展和贯通.微震活动规律与背景应力场表现出了很好的一致性,采用不同的科研手段分析和预测注浆帷幕共同体背景应力场和微震活动规律的前兆性信息特征,并且初步评价其突水危险性.研究成果可以指导工程技术人员采取相应的开采方式和防治措施,为井下开采活动的正常运行提供安全保障.
NUMERICAL SIMULATION OF COUPLED GAS FLOW IN FAILURE PROCESS OF GASSY COAL-ROCK
含瓦斯煤岩破裂过程流固耦合数值模拟

XU Tao,TANG Chun-an,SONG Li,YANG Tian-hong,LIANG Zheng-zhao,
徐 涛
,唐春安,宋 力,杨天鸿,梁正召

岩石力学与工程学报 , 2005,
Abstract: 根据煤岩体介质变形与瓦斯渗流的基本理论,考虑到煤岩介质材料力学性质的非均匀性特点以及煤岩介质变形破裂过程中透气性的非线性变化特性以及煤岩体变形破裂过程中瓦斯渗流与煤岩体变形间的耦合作用,在岩石破裂过程分析系统(RFPA2D)的基础上,建立了含瓦斯煤岩破裂过程流固耦合作用的RFPA2D–Flow耦合模型,并给出了RFPA2D–Flow耦合模型的数值求解方法。并应用该模型对石门掘进诱发煤与瓦斯的延期突出进行了数值模拟,模拟结果再现了含瓦斯煤岩在瓦斯压力、地应力及煤岩力学性质共同作用下渐进损伤破裂诱致突出的全过程,模拟结果进一步表明延期突出与瞬时突出都是地应力、瓦斯压力和煤体物理力学性质3个因素综合作用的结果,都具备突出的4个阶段,即应力集中阶段、应力诱发煤岩破裂阶段、瓦斯动力驱动裂纹扩展阶段和突出阶段,为进一步深入理解煤与瓦斯突出机理及瓦斯抽放防治突出等提供理论基础和科学依据。
STRESS PARALLEL COMPUTING IN ROCK FAILURE PROCESS ANALYSIS SYSTEM
岩石破裂过程分析系统中的应力并行求解

ZHANG Yong-bin,TANG Chun-an,ZHANG Huai,LIANG Zheng-zhao,MA Tian-hui,YANG Tian-hong,
张永彬
,唐春安,张 怀,梁正召,马天辉,杨天鸿

岩石力学与工程学报 , 2006,
Abstract: Powerful and accurate computation is becoming one of the most important tools for rock failure process analysis and related rock engineering problems.It demands supercomputer or large-scale parallel computer and related software that can be run on them.Common personal computers(PC) and workstations are incapable when they are facing the accurate simulation of micro-scale crack formation and evolution in rocks and other different typs of materials,which requires terascale computing,even petascale super-computing in future.A parallel model of rock failure process analysis is proposed.This model is developed from serial version of rock failure process analysis(RFPA) directly,which has been presented before.Parallelism of finite element method(FEM) in stress module has been completed using discontinuous finite element method and domain decomposition parallel algorithms for parallelization of RFPA.Numerical test shows that the program is robust and possesses good scalability and pocketability.Stress analysis of tens of millions order linear equations has been finished within twenty five minutes on 32-node PC-cluster.
Competing electronic orders on Kagome lattices at van Hove filling
Wan-Sheng Wang,Zheng-Zhao Li,Yuan-Yuan Xiang,Qiang-Hua Wang
Physics , 2012, DOI: 10.1103/PhysRevB.87.115135
Abstract: The electronic orders in Hubbard models on a Kagome lattice at van Hove filling are of intense current interest and debate. We study this issue using the singular-mode functional renormalization group theory. We discover a rich variety of electronic instabilities under short range interactions. With increasing on-site repulsion $U$, the system develops successively ferromagnetism, intra unit-cell antiferromagnetism, and charge bond order. With nearest-neighbor Coulomb interaction $V$ alone (U=0), the system develops intra-unit-cell charge density wave order for small $V$, s-wave superconductivity for moderate $V$, and the charge density wave order appears again for even larger $V$. With both $U$ and $V$, we also find spin bond order and chiral $d_{x^2 - y^2} + i d_{xy}$ superconductivity in some particular regimes of the phase diagram. We find that the s-wave superconductivity is a result of charge density wave fluctuations and the squared logarithmic divergence in the pairing susceptibility. On the other hand, the d-wave superconductivity follows from bond order fluctuations that avoid the matrix element effect. The phase diagram is vastly different from that in honeycomb lattices because of the geometrical frustration in the Kagome lattice.
Transcriptome comparison and gene coexpression network analysis provide a systems view of citrus response to ‘Candidatus Liberibacter asiaticus’ infection
Zheng Zhi-Liang,Zhao Yihong
BMC Genomics , 2013, DOI: 10.1186/1471-2164-14-27
Abstract: Background Huanglongbing (HLB) is arguably the most destructive disease for the citrus industry. HLB is caused by infection of the bacterium, Candidatus Liberibacter spp. Several citrus GeneChip studies have revealed thousands of genes that are up- or down-regulated by infection with Ca. Liberibacter asiaticus. However, whether and how these host genes act to protect against HLB remains poorly understood. Results As a first step towards a mechanistic view of citrus in response to the HLB bacterial infection, we performed a comparative transcriptome analysis and found that a total of 21 Probesets are commonly up-regulated by the HLB bacterial infection. In addition, a number of genes are likely regulated specifically at early, late or very late stages of the infection. Furthermore, using Pearson correlation coefficient-based gene coexpression analysis, we constructed a citrus HLB response network consisting of 3,507 Probesets and 56,287 interactions. Genes involved in carbohydrate and nitrogen metabolic processes, transport, defense, signaling and hormone response were overrepresented in the HLB response network and the subnetworks for these processes were constructed. Analysis of the defense and hormone response subnetworks indicates that hormone response is interconnected with defense response. In addition, mapping the commonly up-regulated HLB responsive genes into the HLB response network resulted in a core subnetwork where transport plays a key role in the citrus response to the HLB bacterial infection. Moreover, analysis of a phloem protein subnetwork indicates a role for this protein and zinc transporters or zinc-binding proteins in the citrus HLB defense response. Conclusion Through integrating transcriptome comparison and gene coexpression network analysis, we have provided for the first time a systems view of citrus in response to the Ca. Liberibacter spp. infection causing HLB.
6-(4-Chlorophenyl)-2-(4-methoxyphenyl)-6,7-dihydro-4H-pyrazolo[5,1-c][1,4]oxazine
Liang-Wen Zheng,Bao-Xiang Zhao
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811025906
Abstract: In the title compound, C19H17ClN2O2, the pyrazole ring is almost planar with a maximum deviation of 0.009 (3) and makes a dihedral angle of 8.96 (9)° with the oxazine ring. The dihedral angles between the pyrazole ring and the chlorine- and methoxy-substituted benzene rings are 50.95 (8) and 13.24 (9)°, respectively. An intermolecular C—H...N hydrogen bond links the molecules into infinite chains along the a axis. The crystal structure is further stabilized by C—H...π interactions.
Factors associated with fasting plasma ghrelin levels in children and adolescents
Chao-Chun Zou, Li Liang, Zheng-Yan Zhao
World Journal of Gastroenterology , 2008,
Abstract: AIM: To measure plasma ghrelin levels in children and adolescents, analyze the associated factors, and investigate the role of ghrelin in obesity, insulin resistance and reproductive physiology.METHODS: A total of 283 subjects aged 4.8-15.8 year were enrolled. Fasting blood samples were collected and plasma ghrelin levels were measured by radioimmunoassay. Fasting glucose (FG), fasting insulin (FI), baseline testosterone (T), estradiol (E2), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), serum total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT) and uric acid (UA) were measured. Body mass index (BMI), insulin resistance by homeostasis model (HOMA-IR) and beta cell function by homeostasis model (HOMA-β) were calculated.RESULTS: The median ghrelin level was 290 ng/L (15.0-1325.0 ng/L). Bivariate correlation analysis showed that ghrelin levels were inversely correlated with BMI, ALT, TG, UA, LH, FI and HOMA-IR (all P < 0.05). No other significant correlation was found between ghrelin levels and age, gender, TC, E2, FSH, PRL, FG and HOMA-β. Stepwise multiple regression analysis showed that only BMI and FI were independent determinants of plasma ghrelin levels in these children and adolescents (P = 0.018 and P = 0.046, respectively), which explained 25.4% of the variance.CONCLUSION: These data suggest that the lower ghrelin levels in obese subjects may be the result of obesity and hyperinsulinemia, which is very common in obese subjects. Moreover, ghrelin may regulate human reproductive physiology indirectly.
An Index for Characterization of Natural and Non-Natural Amino Acids for Peptidomimetics
Guizhao Liang, Yonglan Liu, Bozhi Shi, Jun Zhao, Jie Zheng
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067844
Abstract: Bioactive peptides and peptidomimetics play a pivotal role in the regulation of many biological processes such as cellular apoptosis, host defense, and biomineralization. In this work, we develop a novel structural matrix, Index of Natural and Non-natural Amino Acids (NNAAIndex), to systematically characterize a total of 155 physiochemical properties of 22 natural and 593 non-natural amino acids, followed by clustering the structural matrix into 6 representative property patterns including geometric characteristics, H-bond, connectivity, accessible surface area, integy moments index, and volume and shape. As a proof-of-principle, the NNAAIndex, combined with partial least squares regression or linear discriminant analysis, is used to develop different QSAR models for the design of new peptidomimetics using three different peptide datasets, i.e., 48 bitter-tasting dipeptides, 58 angiotensin-converting enzyme inhibitors, and 20 inorganic-binding peptides. A comparative analysis with other QSAR techniques demonstrates that the NNAAIndex method offers a stable and predictive modeling technique for in silico large-scale design of natural and non-natural peptides with desirable bioactivities for a wide range of applications.
Spin precession caused by spin-spin interaction between bounded electrons in quantum dots
Pei Wang,Jin-liang Zheng,Xuean Zhao
Physics , 2006, DOI: 10.1016/j.physe.2006.12.060
Abstract: In this paper, we study the spin-spin interaction between two electrons bounded in a quantum dot. The result shows that spin-spin interaction will cause a pair of spins precessing synchronously. If the two spins are parallel at initial time, the total spin oscillates as a cosine function. If the two spins are antiparallel at initial time, the total spin keeps zero. The precessing period is proportional to the cube of quantum dot radius. For a 2D round quantum dot with radius $R=50{\text{nm}}$, the precessing period equals nearly $12\mu {\text{s}}$.
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