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Search Results: 1 - 10 of 139820 matches for " LI Xi-bing "
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Fractal Property of Granite Failure under Coupled Static-Dynamic Load
动静组合加载作用下花岗岩破碎的分形特征

WANG Qi-sheng,LI Xi-bing,
王其胜
,李夕兵

实验力学 , 2009,
Abstract: 在分离式霍普金森压杆实验装置上进行了花岗岩破坏的动静组合加载实验.通过对受载后岩样破碎块度进行筛分统计,得到了该加载条件下岩石破碎的粒度分布.在此基础上,通过理论计算公式,进一步得到了相应的破碎分形维数,分别探讨了静载荷和冲击载荷对分维数的影响.结果表明,动静组合加载作用下花岗岩破碎分维值在2.0~2.8之间;相同静载不同动载下,花岗岩的破碎分维值与试样的应变率有关,随应变率增大而增大;而在相同冲击动载下,静载荷变化对分形维数的影响不大.
STUDY ON FRACTAL GRADATION OF TAILINGS AND KNOWLEDGE BANK OF ITS CEMENTING STRENGTH
尾砂分形级配与胶结强度的知识库研究

LIU Zhi-xiang,LI Xi-bing,
刘志祥
,李夕兵

岩石力学与工程学报 , 2005,
Abstract: Characteristics of tailings gradation are studied by using fractal theory. Experimental data about the fractal gradations of tailings material and their cementing strength from a lot of mines are analyzed. Neural network is used to establish the model of knowledge bank which embodies the relations between strengths of cemented tailings and content of cement,consistence,fractal dimension of porosity and correlation coefficient of fractal dimension. Combining grading method with chaotic optimization,the neural network model achieves rapid training and avoids local minimum when there are a lot of samples to be trained. Research results show that the strengths of cemented tailings increase with the decrease of fractal dimension of porosity and with the increase of the correlation coefficients of fractal dimension. Because fractal dimension of porosity and its correlation coefficient embody the global distribution information of tailing granule,they can be used as a standard of rationality of gradation. According to gradation of tailings,the knowledge bank model can predict the strengths of cemented tailings in different contents of cement or consistence,and guide filling design in mine.
ANALYSIS OF ENERGY DISTRIBUTIONS OF MILLISECOND BLAST VIBRATION SIGNALS USING THE WAVELET PACKET METHOD
多段微差爆破振动信号频带能量分布特征的小波包分析

LING Tong-hua,LI Xi-bing,
凌同华
,李夕兵

岩石力学与工程学报 , 2005,
Abstract: Blast vibration analysis is the foundation for studying the control of blasting vibration damage. Based on the characteristics of short-time non-stationary random signals,this paper investigates the energy distributions of blasting vibration signals by means of the wavelet packet analysis technique. In this paper,the characteristics of wavelet transform and wavelet packet analysis are briefly introduced. Then,6 sets of blasting vibration signals of multi-interval-time in millisecond blasts are analyzed by using the wavelet packet analysis technique with MATLAB. Energy distributions for different frequency bands are obtained. The results show that the wavelet packet analysis method is an effective means for studying seismic effect induced by blasting,and is especially useful for establishing the velocity-frequency criteria.
RESEARCH ON CHAOS AND INTELLIGENT IDENTIFICATION OF ACOUSTIC EMISSION IN ROCK MASS
岩体声发射混沌与智能辨识研究

LI Xi-bing,LIU Zhi-xiang,
李夕兵
,刘志祥

岩石力学与工程学报 , 2005,
Abstract: Acoustic emission(AE) in rock specimen was tested under loading and breakage,and AE in rock engineering was surveyed. Action laws of AE in rock mass were researched with chaotic kinetics,and chaotic attractors of AE in different stages were calculated during deformation and breakage in rock engineering. By coupling chaos with neural network,a prediction model of AE was established. According to characteristics of AE in different stages,an intelligent identification model for analyzing stability in rock engineering was created. Research results show that there are four different stages in AE activities,i. e.,stable period,earlier active period, intensely active period,and reversal period. Breakage occurs in the reversal period with abnormal AE and diminishing value of chaotic attractor. In-situ case verifies that chaotic kinetics can reflect the characteristics of and the intelligent identification model proposed in this paper is able to predict and analyze stability in rock engineering,especially in deep mining.
Hydrothermal Synthesis and Photocatalytic Properties of Cu-doped BiVO4 Microsheets
LIU Guo-Cong, JING Zhen, ZHANG Xi-Bing, LI Xian-Feng, LIU Hong
无机材料学报 , 2013, DOI: 10.3724/sp.j.1077.2013.12204
Abstract: Using Bi(NO3)3·5H2O, NaVO3 and Cu(NO3)2·3H2O as raw materials, Cu-doped BiVO4 microsheets were synthesized by ultrasonic-hydrothermal process with cetyltrimethyl ammonium bromide (CTAB) as template. The as-prepared samples were investigated by XRD, XPS, SEM, HRTEM, UV-Vis and BET tests. The results reveal that uniform and well crystallized Cu/BiVO4 microsheets in monoclinic crystal structure, with length of 1.0–2.0 μm, width of 0.5–2.0 μm and thickness of 200–300 nm, could be obtained via an ultrasonic-hydrothermal route assisted by 2.0 g CTAB. Compared with BiVO4 particles, Cu/BiVO4 nanosheets show a little red shift in the absorption band, resulting in a narrowed band gap (<2.4 eV). For 5.0wt% Cu/ BiVO4 microsheet, its photodegradation rate constant K is5.89 ×10–2 /min and the best photocatalytic activity is found with a 100% degradation of methylene blue (MB) with 10 mg/L concentration under visible-light irradiation for 60 min.
On the Acoustic Emission (AE) Energy Characteristics of Rock Subjected to Stress Waves
应力波作用下岩石声发射能量特征

WAN Guo-xiang,WANG Qi-sheng,LI Xi-bing,
万国香
,王其胜,李夕兵

实验力学 , 2012,
Abstract: Acoustic emission experiment of rock failure subjected to stress waves was carried out based on SHPB (split Hopkinson pressure bar) experimental system. The variation of acoustic emission energy of granite subjected to this loading was obtained. Experimental results show that the variation of AE energy presents two different features: mode I, energy decays rapidly after peak value, however, at the end of the loading, energy rises and "inflection point"appears; mode II, energy decays slowly after peak value, but no "inflection point"appears. Through analysis of rock fragmentation, relation between the AE peak energy and the fractal dimension value is obtained. Above results may be helpful to both theory and practice for seeking precursory characteristics of AE of rock mass subjected to stress wave.
THEORETICAL ANALYSIS AND EXPERIMENTS OF ROCK FRAGMENTATION UNDER COUPLING DYNAMIC AND STATIC LOADS
动静载荷耦合作用下岩石破碎理论分析及试验研究

ZHAO Fu-jun,LI Xi-bing,FENG Tao,XIE Shi-yong,
赵伏军
,李夕兵,冯涛,谢世勇

岩石力学与工程学报 , 2005,
Abstract: According to the fracture characteristics of rock under indenter,the relations between the length of the median,radial and lateral cracks and the loading parameters of impact hammer,impact speed and static pressure were determined. The cutting effects of rock influenced by impact frequency were also analyzed. On the multifunctional testing device,the indentation and cutting test under coupling dynamic and static loads were conducted on granite. Experimental results show that the cutting effects of rock can be improved greatly under the combined loads,the special energy consumption of rock fragmentation varies with the ratio of impact point space to cutting depth,and has an optimum value at which the cutting effects of rock are optimum. The reasonable method of fragmenting rock is that enough large crack area is caused firstly by impact load and then rock is cut by cutting load and static load. High energy,high frequency and small impact space have good effect on cutting the brittle hard rock.
The relation between the frequency of electromagnetic radiation (EMR) induced by rock fracture and attribute parameters of rock masses
岩石破裂电磁辐射频率与岩石属性参数的关系

LI Xi-Bing,WAN GUO-Xiang,ZHOU Zi-Long,
李夕兵
,万国香,周子龙

地球物理学报 , 2009,
Abstract: 为进一步明确岩石破裂电磁辐射频率特征,基于岩石破裂电磁辐射是由岩石破裂时传播裂纹引起原子扰动产生的假说,通过断裂力学理论中小范围屈服条件下张开位移法计算岩石破裂时的裂纹宽度,由单脉冲电磁辐射频率与裂纹宽度之间的关系.研究电磁辐射频率与岩石属性参数之间的关系,并给出了它们之间的关系表达式;单独讨论了不同属性参数对电磁辐射频率的影响.结果表明,电磁辐射频率随弹性模最增大而增大,随岩样尺寸和强度增大而减小.随泊松比的变化、岩石弹模的不同电磁辐射频率有变化;当弹模较小时,泊松比的影响也较小,而当弹模很大,即岩石刚度很大时,泊松比的增大会导致频率的增大;裂纹初始长度的变化受试件尺寸的影响,进而影响频率,当尺寸较大时,裂纹长度对频率影响较小,当尺寸较小时,频率随裂纹长度增大而增大.通过计算几种常见岩石破裂时电磁辐射频率值发现,岩石破裂时电磁辐射频率达到10.Hz量级,这与现有的实验结果相吻合.
CATASTROPHIC MODEL AND TESTING STUDY ON FAILURE OF STATIC LOADING ROCK SYSTEM UNDER DYNAMIC LOADING
动静组合载荷作用下岩石失稳破坏的突变理论模型与试验研究

ZUO Yu-jun,LI Xi-bing,MA Chun-de,ZHANG Yi-ping,WANG Wei-hua,
左宇军
,李夕兵,马春德,张义平,王卫华

岩石力学与工程学报 , 2005,
Abstract: The stability and its changing law of uniaxial static loading rock system are analyzed by the catastrophe theory. The relationship between dynamic loading and the response of uniaxial static loading rock system is nonlinear and changing law of self-vibration frequency of the system is found out to be adherent to the nonlinear dynamics model of uniaxial static loading rock system. It is shown that when dynamic loading frequency and amplitude reach certain value,fierce jump of amplitude of uniaxial static loading rock system under dynamic loading will occur,then failure of rock specimen subsystem will appear. And the intensity of dynamic signal plays a decisive role in the evolution of uniaxial static loading rock system under dynamic loading. These theoreticalanalytical results are proved by experiment on uniaxial static loading rock system under dynamic loading.
Expression profile analysis of Peptide5 and Peptide6 in Arabidopsis
拟南芥Peptide5和Peptide6的表达谱分析

JIANG Xi-Bing,YU Di-Qiu,
蒋细兵
,余迪求

遗传 , 2008,
Abstract: 通过对5个拟南芥(Arabidopsis thaliana L.)预测性多肽进行RT-PCR分析,在mRNA水平证实了Peptide5和Peptide6预测性多肽的真实性。表达谱分析表明:两基因在不同的发育期和不同的组织普遍表达,为组成型基因;对NaCl、聚乙二醇4000(PEG4000)、茉莉酸甲酯(MeJA)、水杨酸(sA)、机械损伤和冷害做出基因转录水平的响应。启动子顺式作用元件分析提示,拟南芥Peptide5基因可能参与了次生木质部的形成。
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