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Reliability Analysis of Free Jet Scour Below Dams
Chuanqi Li,Shuai Wang,Wei Wang
Entropy , 2012, DOI: 10.3390/e14122578
Abstract: Current formulas for calculating scour depth below of a free over fall are mostly deterministic in nature and do not adequately consider the uncertainties of various scouring parameters. A reliability-based assessment of scour, taking into account uncertainties of parameters and coefficients involved, should be performed. This paper studies the reliability of a dam foundation under the threat of scour. A model for calculating the reliability of scour and estimating the probability of failure of the dam foundation subjected to scour is presented. The Maximum Entropy Method is applied to construct the probability density function (PDF) of the performance function subject to the moment constraints. Monte Carlo simulation (MCS) is applied for uncertainty analysis. An example is considered, and there liability of its scour is computed, the influence of various random variables on the probability failure is analyzed.
Maximum-Entropy Method for Evaluating the Slope Stability of Earth Dams
Chuanqi Li,Wei Wang,Shuai Wang
Entropy , 2012, DOI: 10.3390/e14101864
Abstract: The slope stability is a very important problem in geotechnical engineering. This paper presents an approach for slope reliability analysis based on the maximum-entropy method. The key idea is to implement the maximum entropy principle in estimating the probability density function. The performance function is formulated by the Simplified Bishop’s method to estimate the slope failure probability. The maximum-entropy method is used to estimate the probability density function (PDF) of the performance function subject to the moment constraints. A numerical example is calculated and compared to the Monte Carlo simulation (MCS) and the Advanced First Order Second Moment Method (AFOSM). The results show the accuracy and efficiency of the proposed method. The proposed method should be valuable for performing probabilistic analyses.
Bis(2-methyl-1H-benzimidazol-3-ium) naphthalene-1,5-disulfonate
Shuai-Shuai Wei,Shou-Wen Jin,Qiong Dong,Xin-Chao Cao
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812039396
Abstract: The asymmetric unit of the title compound, 2C8H9N2+·C10H6O6S22 , contains a 2-methylbenzimidazolium cation and one half of a naphthalene-1,5-disulfonate anion. The formula unit is generated by an inversion center. In the crystal, N—H...O hydrogen bonds link the components into chains along [001]. In addition, weak C—H...O hydrogen bonds and weak C—H...π interactions are observed. The methyl H atoms were refined as disordered over two sets of sites with equal occupancy.
Termination of Ca2+ Release for Clustered IP3R Channels
Sten Rüdiger ,Peter Jung,Jian-Wei Shuai
PLOS Computational Biology , 2012, DOI: 10.1371/journal.pcbi.1002485
Abstract: In many cell types, release of calcium ions is controlled by inositol 1,4,5-trisphosphate () receptor channels. Elevations in concentration after intracellular release through receptors (R) can either propagate in the form of waves spreading through the entire cell or produce spatially localized puffs. The appearance of waves and puffs is thought to implicate random initial openings of one or a few channels and subsequent activation of neighboring channels because of an “autocatalytic” feedback. It is much less clear, however, what determines the further time course of release, particularly since the lifetime is very different for waves (several seconds) and puffs (around 100 ms). Here we study the lifetime of signals and their dependence on residual microdomains. Our general idea is that microdomains are dynamical and mediate the effect of other physiological processes. Specifically, we focus on the mechanism by which binding proteins (buffers) alter the lifetime of signals. We use stochastic simulations of channel gating coupled to a coarse-grained description for the concentration. To describe the concentration in a phenomenological way, we here introduce a differential equation, which reflects the buffer characteristics by a few effective parameters. This non-stationary model for microdomains gives deep insight into the dynamical differences between puffs and waves. It provides a novel explanation for the different lifetimes of puffs and waves and suggests that puffs are terminated by inhibition while unbinding is responsible for termination of waves. Thus our analysis hints at an additional role of and shows how cells can make use of the full complexity in R gating behavior to achieve different signals.
Self-assembly of two-dimensional DNA crystals
Cheng Song,Yaqing Chen,Shuai Wei,Xiaozeng You,Shoujun Xiao
Chinese Science Bulletin , 2004, DOI: 10.1007/BF03184002
Abstract: Self-assembly of synthetic oligonucleotides into two-dimensional lattices presents a ‘bottom-up’ approach to the fabrication of devices on nanometer scale. We report the design and observation of two-dimensional crystalline forms of DNAs that are composed of twenty-one plane oligonucleotides and one phosphate-modified oligonucleotide. These synthetic sequences are designed to self-assemble into four double-crossover (DX) DNA tiles. The ‘sticky ends’ of these tiles that associate according to Watson-Crick’s base pairing are programmed to build up specific periodic patterns upto tens of microns. The patterned crystals are visualized by the transmission electron microscopy.
Reproduction and analysis of an animal model for assessing the efficacy of debridement agent for firearm injuries
Wei HU,Ai-min WANG,Bo ZHANG,Shuai LIU
Medical Journal of Chinese People's Liberation Army , 2011,
Abstract: Objective To reproduce an animal model for assessing the efficacy of a debridement agent for firearm injuries.Methods Rabbits and goats(4 each) were assigned to group A and group B,and 8 pigs were randomly divided into group C and group D(4 each).Spherical projectiles(initial velocity 850m/s,weight 0.375g) fired by a 53-type musket were used to produce soft tissue injuries of hind limbs in group A,B and C,and cylindrical projectiles(initial velocity 950m/s,weight 0.87g) fired by a 53-type musket were used in group D.The local traumatic condition,pathological zones,bacterial counts and cytokine levels of tissues around the wound tracks were measured,and the constancy of the model was evaluated using coefficient of variation(CV).Results Penetrating wounds of soft tissues were made in hind limbs in all animal.The consistency degree of wound track entrance size,exit size and volume of wound track was higher in group B and D than in group A and D.Typical pathological zones of firearm wounds were observed under light microscope,and it was found that the local traumatic condition was more constant in group C than in other three groups.Determination of bacterial counts showed a heavy bacterial contamination of tissues in wound tracks,but significant difference was found among these groups.TNF-α and IL-6 levels in wound tissues increased gradually within 24 hours after the injury,and the changes in TNF-α and IL-6 levels in plasma showed a similar trend,but all the cytokine levels were low.Conclusions Simple soft tissue penetrating wounds in posterior limbs of pigs produced by spherical projectiles(velocity 850m/s,weight 0.375g) possess typical histopathological and bacterial characteristics of firearm injuries.This model is simple to reproduce,the traumatic condition is constant,and has a good reproducibility.
Current clinical practice for Parkinson’s disease among Chinese physicians, general neurologists and movement disorders specialists: a national survey
Chen Wei,Chen Shuai,Xiao Qin,Wang Gang
BMC Neurology , 2012, DOI: 10.1186/1471-2377-12-155
Abstract: Background To explore current status and choices regarding diagnosis and treatment of Parkinson’s disease (PD) among physicians, general neurologists and movement disorders specialists in China via a national survey. Methods The cross-sectional questionnaire-based survey was conducted from November, 2010 to July, 2011. Six hundreds and twelve doctors from different cities in China were recruited for this study. Results 68.6% (n=420) and 23.9% (n=146) of doctors have read the national and international guidelines, respectively. There was a larger proportion of movement disorders specialists reading the guidelines, in contrast to physicians and general neurologists (P<0.001). Up to 76.4% (n=465) and 81.8% (n=498) of doctors would choose standard oral levodopa test and conventional MRI(with T1 and T2), respectively; Whereas susceptibility weighed imaging(SWI)(16.1%; n=98), transcranial sonography (TCS) (1.8%; n=11) and functional neuroimaging test, such as single photon emission computed tomography(SPECT) (10.2%; n=62) and positron emission tomography(PET)(13.3%; n=81) were less used for suspected patients with PD in clinical practice. Doctors at different levels or from different hospitals and cities would choose different medication for motor complications and non-motor symptoms of patients with PD, in addition to initial drug selection for newly diagnosed PD. Doctors who had read the guidelines had significantly better knowledge of medication selections for PD under specific circumstances. Conclusions Compared with commonly employed standard oral levodopa test and conventional MRI, SWI complements MRI, TCS and functional neuroimaging were less performed for diagnosis of PD in clinical practice in China. The choices of diagnostic methods and therapeutic strategy of PD vary among physicians, general neurologists and movement disorders specialists. Guideline awareness is markedly beneficial to reasonable PD medications strategy in China.
Characterization of Mechanical and Biological Properties of 3-D Scaffolds Reinforced with Zinc Oxide for Bone Tissue Engineering
Pei Feng, Pingpin Wei, Cijun Shuai, Shuping Peng
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087755
Abstract: A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam1/2, and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.
Glass transition with decreasing correlation length during cooling of Fe50Co50 superlattice and strong liquids
Shuai Wei,Isabella Gallino,Ralf Busch,C. Austen Angell
Physics , 2010, DOI: 10.1038/nphys1823
Abstract: The glass transition GT is usually thought of as a structural arrest that occurs during the cooling of a liquid, or sometimes a plastic crystal, trapping a metastable state of the system before it can recrystallize to stabler forms1. This phenomenon occurs in liquids of all classes, most recently in bulk metallic glassformers2. Much theoretical interest has been generated by the dynamical heterogeneity observed in cooling of fragile liquids3, 4, and many have suggested that the slow-down is caused by a related increasing correlation length 5-9. Here we report both kinetics and thermodynamics of arrest in a system that disorders while in its ground state, exhibits a large !Cp on arrest (!Cp = Cp,mobile - Cp,arrested), yet clearly is characterized by a correlation length that is decreasing as GT is approached from above. We show that GT kinetics in our system, the disordering superlattice Fe50Co50, satisfy the kinetic criterion for ideally 'strong' glassformers10, and since !Cp behavior through Tg also correlates10, we propose that very strong liquidsand very fragile liquids exist on opposite flanks of an order-disorder transition - one that is already known for model systems.
Thermodynamics, kinetics and fragility of bulk metallic glass forming liquids
Ralf Busch,Zach Evenson,Isabella Gallino,Shuai Wei
Physics , 2014,
Abstract: This review deals with the kinetic and thermodynamic fragility of bulk metallic glass forming liquids. The experimental methods to determine the kinetic fragility, relaxation behavior and thermodynamic functions of undercooled metallic liquids are introduced. Existing data are assessed and discussed using the Vogel-Fulcher-Tammann equation and in the frameworks of the Adam-Gibbs as well as the Cohen-Turnbull free volume approach. In contrast to pure metals and most non glass forming alloys, bulk glass formers are moderately strong liquids. In general the fragility parameter $D^{*} $ increases with the complexity of the alloy with differences between the alloy families, e.g. noble-metal based alloys being more fragile than Zr-based alloys. At least some bulk metallic glass forming liquids, such as Vitreloy 1, undergo transitions from a fragile state at high temperatures to a strong state at low temperatures with indications that in Zr-based alloys this behavior is a common phenomenon.
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