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Search Results: 1 - 10 of 28003 matches for " MA Liqiang "
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Experimental evidence for seismic nucleation phase
Shengli Ma,Jin Ma,Liqiang Liu
Chinese Science Bulletin , 2002, DOI: 10.1360/02tb9174
Abstract: The friction experiments on macroscopically homogeneous and non-homogeneous faults were performed by using a double-shear friction rig, and the waveforms of acoustic emission and the fault slip corresponding to the stick-slip instability events were analyzed. The results indicate that there exist two types of nucleation phase for stick-slip instability of non-homogeneous faults, and one is coincident with the preslip model, the other with the cascade model. It is concluded that the seismic nucleation phase exists objectively, and its generation is related to heterogeneity of fault.
Experimental evidence for seismic nucleation phase

MA Shengli,MA Jin,LIU Liqiang,

科学通报(英文版) , 2002,
Abstract: The friction experiments on macroscopically homogeneous and non-homogeneous faults were performed by using a double-shear friction rig, and the waveforms of acoustic emission and the fault slip corresponding to the stick-slip instability events were analyzed. The results indicate that there exist two types of nucleation phase for stick-slip instability of non-homogeneous faults, and one is coincident with the preslip model, the other with the cascade model. It is concluded that the seismic nucleation phase exists objectively, and its generation is related to heterogeneity of fault.``
Coordinated Control of Traffic Signals for Multiple Intersections  [PDF]
Liqiang Fan
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.513197
Abstract: The proper phase difference of traffic signals for adjacent intersections could decrease the time of operational delay. Some theorems show how to minimize the total average delay time for vehicle operating at adjacent intersections under given conditions. If the distance and signal cycles of adjacent intersections satisfy with specific conditions, the total average delay time would achieve zero. If the signal cycles of adjacent intersections and the phase difference of them are co-prime numbers, the total average delay time would be a constant. In general, if signal cycles of adjacent intersections and the phase difference of them are reducible numbers, the minimum total average delay time would be solved by the given algorithm. Numerical experiments have verified the rationality of these theorems.
Recent Development of the Synthesis and Engineering Applications of One-Dimensional Boron Nitride Nanomaterials
Changhui Sun,Hongxiao Yu,Liqiang Xu,Qiang Ma,Yitai Qian
Journal of Nanomaterials , 2010, DOI: 10.1155/2010/163561
Abstract: One-dimensional (1D) nanomaterials with novel photoelectric, magnetic, mechanical, and electronic transport properties have long been the research focus throughout the world. Herein, the recent achievements in preparation of 1D boron nitride nanomaterials, including nanotubes, nanowires, nanoribbons, nanorods, and nanofibres are reviewed. As the most intriguing and researched polymorph, boron nitride nanotubes (BNNTs) are introduced thoroughly involving their functionalization and doping. The electronics and engineering applications of 1D boron nitride nanomaterials are illustrated in nanoscale devices, hydrogen storage, polymer composites, and newly developed biomedical fields in detail. 1. Introduction A nanoscience and nanotechnology revolution initiated by the observation of carbon nanotubes (CNTs) [1] has rapidly swept the world over the last couples of decades. A number of peculiar phenomena were found at the nanoscale. Of the epoch-making revolution, nanomaterials lie in the central position and construct a bridge between nanoscience and nanotechnology. Synthesis and characterization of new types of nanomaterials have attracted enormous concentration of scientists in chemistry, physics and materials. Of all, 1D nanomaterials such as tubes, wires, ribbons, fibers, and rods with exceptional electronic, mechanical, optical and magnetic properties have been widely researched and used as building blocks in nanoscale devices [2]. It is generally suggested that quantum confinement in 1D nanostructures leads to novel electronic and transport properties, which provides a good model to investigate the effect of dimensionality and reduced size on the above properties of 1D nanomaterials [3]. Light-weight 1D nanomaterials with large elastic modulus can be promising candidate in engineering field and used as reinforcement agent into composite materials [4]. Hexagonal boron nitride (h-BN) with layered structure analogous to graphite is an important III-V material. Stimulated by rapid development of carbon nanomaterials, a series of boron nitride nanostructures have been synthesized, especially 1D nanomaterials such as nanotubes, nanowires, nanoribbons, nanofibers, and nanorods (Figure 1) [5–9]. One-dimensional boron nitride nanomaterials exhibit not only excellent thermal conductivity and high elastic modulus comparable to these of carbon materials but better thermal and chemical stability. Contrary to carbon with good electrical conductivity, boron nitride is a nearly electrical insulator with a large band gap of 5.5?ev which is independent of tube diameter
Progress in Biodiversity Informatics
Lisong Wang,Bin Chen,Liqiang Ji,Keping Ma
生物多样性 , 2010,
Abstract: Biodiversity Informatics is a young and rapidly growing field that brings information science and technologies to bear on the data and information generated by the study of biodiversity and related subjects. Recent years, biodiversity informatics community has made an extraordinary effort to digitize primary biodiversity data, and develop modelling tools, data integration, and county/ regional/ global biodiversity networks. In doing so, the community is creating an unprecedented global sharing of information and data produced by biodiversity science, and encouraging people to consider, survey and monitor natural biodiversity. Due to success of several international biodiversity informatics projects, such as Species 2000, Global Biodiversity Information Facility, Barcoding of Life and Encyclopedia of Life, digitized information on species inventories, herbarium specimens, multimedia and literature is available through internet. These projects not only make great contributions to sharing digitized biodiversity data, but also in prompting the implementation of important biodiversity information standards, such as Darwin Core, and in the establishment of regional and national biodiversity networks. These efforts will facilitate the future establishment of a strong information infrastructure for data sharing and exchange at a global scale. Besides focusing on browsing and searching digitized data, scientists should also work on building data mining and modeling, such as MAXENT for Ecological Niche Modelling and LifeDesk for taxonomist’s knowledge management. At the same time, the idea of citizen sciences gains popularity showing us the benefit of the public working closely with the scientific community in completing internet-based biodiversity informatics activities. Therefore, biodiversity informatics has broad prospects, and is helping to build strong facilities that will aid in implementing the goals set by Global Plant Conservation Strategy and related international treaties, resolving biodiversity crises and the management of biodiversity resources in global climate change scenarios.
Epidermal growth factor (EGF) and interleukin (IL)-1β synergistically promote ERK1/2-mediated invasive breast ductal cancer cell migration and invasion
Ma Liqiang,Lan Fenghua,Zheng Zhiyong,Xie Feilai
Molecular Cancer , 2012, DOI: 10.1186/1476-4598-11-79
Abstract: Background Patients with invasive breast ductal carcinoma (IBDC) with metastasis have a very poor prognosis. Little is known about the synergistic action of growth and inflammatory factors in IBDC metastases. Methods The expression of activated extracellular signal-regulated kinase1/2 (phosphorylated or p-ERK1/2) was analyzed by immunohistochemistry in IBDC tissue samples from 80 cases. BT474 IBDC cell migration and invasion were quantified using the Transwell assay. Matrix metalloproteinase (MMP)-9 expression and activity were analyzed by RT-PCR, Western blotting and zymography. Activator protein (AP)-1 activity was measured with a luciferase reporter gene assay. The Wilcoxon signed-rank test, Chi-square test, the partition of Chi-square test, independent t-test, and Spearman’s method were used for the statistical analysis. Results Phosphorylated ERK1/2 was detected in 58/80 (72.5%) IBDC tissues, and was associated with higher TNM stage and lymph node metastasis, but not patient age or tumor size. Individually, epidermal growth factor (EGF), and interleukin (IL)-1β activated ERK1/2, increased cell migration and invasion, MMP-9 expression and activity, AP-1 activation in vitro and the expression of p-ERK1/2 was positively correlated with EGF expression levels, as well as IL-1β, MMP-9 and c-fos in IBDC tissue samples. Co-stimulation with EGF and IL-1β synergistically increased ERK1/2 and AP-1 activation, cell migration and invasion, and MMP-9 expression and activity. Inhibition of ERK1/2 using U0126 or siRNA abolished EGF and/or IL-1β-induced cell migration and invasion in a dose-dependent manner. Conclusion Activated ERK1/2 was associated with higher TNM stage and lymph node metastasis in IBDC. Both in vitro and in vivo studies indicated that ERK-1/2 activation may increase the metastatic ability of IBDC cells. Growth and inflammatory factors synergistically induced IBDC cell migration and invasion via ERK1/2 signaling, AP-1 activation and MMP-9 upregulation.
K-Nearest Neighbor Based Missing Data Estimation Algorithm in Wireless Sensor Networks  [PDF]
Liqiang Pan, Jianzhong Li
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.22016
Abstract: In wireless sensor networks, the missing of sensor data is inevitable due to the inherent characteristic of wireless sensor networks, and it causes many difficulties in various applications. To solve the problem, the missing data should be estimated as accurately as possible. In this paper, a k-nearest neighbor based missing data estimation algorithm is proposed based on the temporal and spatial correlation of sensor data. It adopts the linear regression model to describe the spatial correlation of sensor data among different sensor nodes, and utilizes the data information of multiple neighbor nodes to estimate the missing data jointly rather than independently, so that a stable and reliable estimation performance can be achieved. Experimental results on two real-world datasets show that the proposed algorithm can estimate the missing data accurately.
Cryogenic System for PKU-FEL  [PDF]
Lianyou Xiong, Nan Peng, Wenhai Lu, Liqiang Liu, Xiaojun Liu, Jing Li, Liya Ma, Bing Dong, Yongcheng Jiang, Jiancheng Tang, Liang Zhang
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.46A001

PKU-FEL based on superconducting (SC) accelerator facility is under construction at PekingUniversity. It will run in IR (5 - 10 μm) and THz (100 - 3000 μm) region as an ideal experimental FEL platform for universities. The SC accelerator facility is composed of a DC-SC injector and a 1.3-GHz 2 × 9-cell SC accelerator. In order to better the performance, the injector and the accelerator are bath-cooled by 2 K super fluid helium in cryostats. A 2 K cryogenic system has been designed, constructed and assembled.

Temporal and spatial distribution of microfractures in granites of different structures under triaxial compression and its significance in seismology
Liqiang Liu,Shengli Ma,Jin Ma,Xinglin Lei,K. Kusunose,O. Nishizawa,L. Jouniaux
Chinese Science Bulletin , 1999, DOI: 10.1007/BF02885854
Abstract: The temporal and spatial distribution of microfracturing activity in two kinds of granite under triaxial compression has been studied by using a new acoustic emission system. For Inada granite, there is no clear clustering of acoustic emission events in time and space, thus it is difficult to exactly deduce the time and position of the major fracturing. While for Mayet granite, acoustic emission events are clustered in time and space, so the time and position of the major fracturing can be exactly predicted according to microfracturing process. Such a difference may result from the difference in deformation mode caused by different rock structures.
Monoclonal Antibody-Based Sandwich ELISA for the Detection of Staphylococcal Enterotoxin A
Hua Kuang,Wenbing Wang,Liguang Xu,Wei Ma,Liqiang Liu,Libing Wang,Chuanlai Xu
International Journal of Environmental Research and Public Health , 2013, DOI: 10.3390/ijerph10041598
Abstract: A sensitive and specific monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (ELISA) was established and validated for the detection of staphylococcal enterotoxin A (SEA). After routine fusion and selection, 10 monoclonal antibodies showed high affinity for SEA. An optimal pair for sandwich ELISA was selected by pairwise interaction analysis. After optimization, the limit of detection (LOD) and linear dynamic range of the method were established, and were found to be 0.0282 ng/mL and 0.06–2 ng/mL, respectively. The recovery in pure milk ranged from 82.67% to 111.95% and the intra- and inter-assay coefficients of variation ranged from 3.16% to 6.05% and from 5.16% to 10.79%, respectively. Cross-reactivity with staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SEC), staphylococcal enterotoxin D (SED), and staphylococcal enterotoxin E (SEE) in this method were insignificant. These results indicate that the sandwich ELISA method developed in our study is effective for routine identification of SEA in food samples.
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