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Search Results: 1 - 10 of 19127 matches for " Chunhui Song "
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On the existence of weak solutions to the three-dimensional steady compressible Navier-Stokes equations in bounded domains
Song Jiang,Chunhui Zhou
Mathematics , 2011,
Abstract: We prove the existence of a weak solution to the three-dimensional steady compressible isentropic Navier-Stokes equations in bounded domains for any specific heat ratio \gamma > 1. Generally speaking, the proof is based on the new weighted estimates of both pressure and kinetic energy for the approximate system which result in some higher integrability of the density, and the method of weak convergence. Comparing with [12] where the spatially periodic case was studied, here we have to control the additional integral terms of both pressure and kinetic energy involving with the points near the boundary which become degenerate when the points approach the boundary. Such integral terms are estimated using some new techniques, i.e., we use the techniques of the mirror image and boundary straightening to prove that the weighted estimates of both pressure and kinetic energy for the points near the boundary can be controlled by the weighted estimates for the points on the boundary. Moreover, we prove that once the weighted estimates of the kinetic energy in the direction of the unit normal to the boundary are bounded, we can control the weighted estimates of the total energy on the boundary.
Contrasting Drought Tolerance in Two Apple Cultivars Associated with Difference in Leaf Morphology and Anatomy  [PDF]
Tuanhui Bai, Zhanying Li, Chunhui Song, Shangwei Song, Jian Jiao, Yuchen Liu, Zhidan Dong, Xianbo Zheng
American Journal of Plant Sciences (AJPS) , 2019, DOI: 10.4236/ajps.2019.105051
Abstract: Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. The present study examined the effects of drought on photosynthesis and water use efficiency (WUE) of two apple cultivars (Honeycrisp and Yanfu 3) that differ in drought tolerance. The results showed that the photosynthetic rate decreased in response to drought stress for both cultivars, with significant differences in intensity. Values for net photosynthetic rate (Pn) in stressed Yanfu 3 remained significantly lower than in the controls, while, for Honeycrisp, only a slight drop in photosynthesis. Similarly, stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) were markedly reduced in Yanfu 3 under drought stress. However, Honeycrisp showed only minor changes. Under drought stress, the contents of Chl a, Chl b and Chl t in Yanfu 3 were all decreased significantly compared with the control. However, little difference in Honeycrisp was noted between stressed plants and controls. Values for WUE in stressed Yanfu 3 remained higher than in the controls from day 3 until the end of the experiment, while no significant difference was observed in Honeycrisp. Furthermore, Honeycrisp also exhibited superior physiological traits, as indicated by its anatomical and morphological characteristics. Therefore, we conclude that the superior drought tolerance of Honeycrisp was due to its anatomical and morphological characteristics, which possibly contributed to the maintenance of higher photosynthetic capacity than Yanfu 3.
Research on the Filtering Algorithm in Speed and Position Detection of Maglev Trains
Chunhui Dai,Zhiqiang Long,Yunde Xie,Song Xue
Sensors , 2011, DOI: 10.3390/s110707204
Abstract: This paper introduces in brief the traction system of a permanent magnet electrodynamic suspension (EDS) train. The synchronous traction mode based on long stators and track cable is described. A speed and position detection system is recommended. It is installed on board and is used as the feedback end. Restricted by the maglev train’s structure, the permanent magnet electrodynamic suspension (EDS) train uses the non-contact method to detect its position. Because of the shake and the track joints, the position signal sent by the position sensor is always aberrant and noisy. To solve this problem, a linear discrete track-differentiator filtering algorithm is proposed. The filtering characters of the track-differentiator (TD) and track-differentiator group are analyzed. The four series of TD are used in the signal processing unit. The result shows that the track-differentiator could have a good effect and make the traction system run normally.
Analysis and Design of a Speed and Position System for Maglev Vehicles
Chunhui Dai,Fengshan Dou,Xianglei Song,Zhiqiang Long
Sensors , 2012, DOI: 10.3390/s120708526
Abstract: This paper mainly researches one method of speed and location detection for maglev vehicles. As the maglev train doesn’t have any physical contact with the rails, it has to use non-contact measuring methods. The technology based on the inductive loop-cable could fulfill the requirement by using an on-board antenna which could detect the alternating magnetic field produced by the loop-cable on rails. This paper introduces the structure of a speed and position system, and analyses the electromagnetic field produced by the loop-cable. The equivalent model of the loop-cable is given and the most suitable component of the magnetic flux density is selected. Then the paper also compares the alternating current (AC) resistance and the quality factor between two kinds of coils which the antenna is composed of. The effect of the rails to the signal receiving is also researched and then the structure of the coils is improved. Finally, considering the common-mode interference, 8-word coils are designed and analyzed.
A Portable and Power-Free Micro?uidic Device for Rapid and Sensitive Lead (Pb2+) Detection
Chunhui Fan,Shijiang He,Gang Liu,Lianhui Wang,Shiping Song
Sensors , 2012, DOI: 10.3390/s120709467
Abstract: A portable and power-free micro?uidic device was designed for rapid and sensitive detection of lead (Pb2+). 11-mercaptoundecanoic acid (MUA)-functionalized gold nanoparticles (MUA-AuNPs) aggregated in the presence of Pb2+ for the chelation mechanism. When we performed this analysis on a polydimethylsiloxane (PDMS) microfluidic chip, the aggregations deposited onto the surface of chip and formed dark lines along the laminar flows in the zigzag microchannels. This visual result can be observed by the naked eye through a microscope or just a drop of water as a magnifier. Ten μM Pb2+ was successfully detected.
Technology and Applications of Microbial Biosensor  [PDF]
Chunhui Dai, Seokheun Choi
Open Journal of Applied Biosensor (OJAB) , 2013, DOI: 10.4236/ojab.2013.23011
Abstract: A microbial biosensor is an analytical device that immobilizes microorganisms onto a transducer for the detection of target analytes. With the development of nanotechnology, nanomaterials have been used to achieve better immobilization for developing a more reliable and selective microbial biosensor. Also, significant progress has been made in the development of transducer technology leading to higher sensitivity. Microbial biosensors have become one of the most useful means of monitoring environmental, food and clinical samples. In this review, we focus on the newly developed technologies and applications of microbial biosensors in recent years.

Associations of IL-4, IL-4R, and IL-13 Gene Polymorphisms in Coal Workers' Pneumoconiosis in China: A Case-Control Study
Meilin Wang, Shasha Wang, Zhifang Song, Xiaomin Ji, Zhengdong Zhang, Jianwei Zhou, Chunhui Ni
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022624
Abstract: Background The IL-4, IL-4 receptor (IL4R), and IL-13 genes are crucial immune factors and may influence the course of various diseases. In the present study, we investigated the association between the potential functional polymorphisms in IL-4, IL-4R, and IL-13 and coal workers' pneumoconiosis (CWP) risk in a Chinese population. Methods Six polymorphisms (C-590T in IL-4, Ile50Val, Ser478Pro, and Gln551Arg in IL-4R, C-1055T and Arg130Gln in IL-13) were genotyped and analyzed in a case-control study of 556 CWP and 541 control subjects. Results Our results revealed that the IL-4 CT/CC genotypes were associated with a significantly decreased risk of CWP (odds ratio (OR) = 0.74, 95% confidence interval (CI) = 0.58–0.95), compared with the TT genotype, particularly among subgroups of age <65 years (OR = 0.68, 95%CI = 0.46–0.99) and dust exposure years ≥26 years (OR = 0.69, 95%CI = 0.50–0.94). Moreover, the polymorphism was significantly associated with risk of CWP patients with stage I. In addition, a combined effect was observed in a dose-dependent manner with increasing numbers of risk variant alleles (Ptrend = 0.023), and individuals with 11–12 risk alleles had a 47% higher risk of CWP than those with 0–8 risk alleles (OR = 1.47, 95% CI = 1.05–2.05). Conclusions Our results suggest that the IL-4 C-590T polymorphism is involved in the etiology of CWP and susceptibility to this disease. Larger studies are warranted to validate our findings.
Synthesis, structure and catalytic behavior of yttrium complexes bearing a diaminobis(phenolate) ligand
FengKui Song,ChunHui Yan,HongMei Sun,YingMing Yao,Qi Shen,Yong Zhang
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0434-6
Abstract: Yttrium complexes stabilized by a diaminobis(phenolate) ligand were synthesized and their catalytic behavior was explored. Reaction of YCl3 with 1 equiv of LNa2 [L= Me2NCH2CH2N{CH2-(2-O-C6H2-tBu2-3, 5)}2] gave the yttrium chloride LYCl(THF) (1) in 92% yield. Complex 1 can be used as starting material to prepare the yttrium amido derivative. Complex 1 reacted with 1 equiv of LiNPh2 in THF to afford the expected yttrium amido complex LYNPh2 (2) in high yield. Both of complexes 1 and 2 have been well detected by elemental analysis, NMR spectra and single-crystal X-ray analysis. It was found that complex 2 can efficiently initiate the ring-opening polymerization of L-lactide and -caprolactone, and a controlled manner is observed in the former case.
Magnetostratigraphy of Late Cenozoic fossil mammals in the northeastern margin of the Tibetan Plateau
Chunhui Song,Xiaomin Fang,Junping Gao,Junsheng Nie,Maodu Yan,Xianhai Xu,Dong Sun
Chinese Science Bulletin , 2003, DOI: 10.1360/03tb9039
Abstract: A number of fossil mammals have been found in the very thick Cenozoic stratigraphy of the Guide Basin in the northeastern margin of the Tibetan Plateau. Some of these are of great significance in mammal evolution and stratigraphic correlation on and around the Tibetan Plateau and North China. However, the chronology of these mammals is poorly constrained. Dating of the mammals will not only place precise age constraints on the mammals, but also provide much information on the related stratigraphy that records the uplift process of the Tibetan Plateau. Detailed paleomagnetism of the upper part of the Cenozoic stratigraphy at He’erjia and Lajigai north of Guide County has revealed magnetic chrons that can be correlated to Gauss and 3An chrons, determining the section spanning about 3.1–6.5 Ma and the first, second and third layers of fossil mammals at about 5.25, 5.1 and 4.4 Ma, respectively. Ages of the significant genus Gazella kueitensis and the Chinese elephant Anancus sinensis are firstly constrained at about 5.25 MaBP and 4.4 Ma, respectively. The mammalian evolution and the associated increase in coarse sediments and sedimentation rate may suggest that the northeastern Tibetan Plateau was uplifted rapidly at that time, and the eastern Tibetan Plateau with its neighboring regions was not high enough to stop mammal exchange between the northern and southern sides of the Tibetan Plateau.
Magnetic properties of surface soils across the southern Tarim Basin and their relationship with climate and source materials
JinBo Zan,XiaoMin Fang,JunSheng Nie,ShengLi Yang,ChunHui Song,Shuang Dai
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-010-4210-4
Abstract: The magnetic susceptibility (χ) of surface soils on the Chinese Loess Plateau (CLP) has strong positive correlation with mean annual precipitation. It is widely accepted that ultrafine magnetite/maghemite grains produced during pedogenesis are responsible for the enhancement of χ, and loess χ on the CLP has been widely used as a proxy for the intensity of the East Asian summer monsoon. However, few works have investigated mechanisms for the enhancement of χ in the case of surface aeolian sediments in westerly-dominated inland China, north of the Tibetan Plateau. Here detailed rock magnetism and grain size studies of 49 surface samples taken across the southern Tarim Basin for different rainfall/temperature/altitude conditions are presented. The results show that samples taken from desert have the lowest χ values and that χ of loessic sand and loess samples decreases with increasing altitude. In addition, the rock magnetism studies suggest that the magnetic properties of surface soils across the southern Tarim Basin are mainly controlled by the concentration of coarse aeolian ferrimagnetic minerals. The contribution of ultrafine pedogenically produced magnetic grains to χ is very limited.
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