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Search Results: 1 - 10 of 32913 matches for " Ning Cheng "
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Switching probability investigation of electric field-induced precessional magnetization switching
Hongguang Cheng,Ning Deng
Physics , 2013,
Abstract: We report theoretical investigation of the switching probability of electric field-induced precessional magnetization switching by solving the Fokker-Planck equation numerically with finite difference method. The switching probability is determined by the net magnetic field induced by the deviation of precession angle from its equilibrium position after precession process. The error rate has the lowest value under an appropriate applied external field for the voltage pulse duration ${\tau}_{pulse}$ a little longer than the half precession period. The calculated results show that ultra-low error rate down to the order of $10^{-12}$ can be achieved for thermal stability factor {\Delta} = 50 and low damping factor material should be used for free layer to improve the switching probability. For parallel (anti-parallel) magnetization to anti-parallel (parallel) magnetization switching process, the spin transfer torque tends to decrease (increase) the error rate when the ${\tau}_{pulse}$ is shorter than the half precession period, and increase (decrease) the error rate when ${\tau}_{pulse}$ is longer than the half-period. These results exhibit potential of electric field-induced precessional magnetization switching for ultra-low power, high speed magnetic random access memory (MRAM) application.
Infinite Horizon LQ Zero-Sum Stochastic Differential Games with Markovian Jumps  [PDF]
Huai-Nian Zhu, Cheng-Ke Zhang, Ning Bin
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.330188
Abstract: This paper studies a class of continuous-time two person zero-sum stochastic differential games characterized by linear It?’s differential equation with state-dependent noise and Markovian parameter jumps. Under the assumption of stochastic stabilizability, necessary and sufficient condition for the existence of the optimal control strategies is presented by means of a system of coupled algebraic Riccati equations via using the stochastic optimal control theory. Furthermore, the stochastic H control problem for stochastic systems with Markovian jumps is discussed as an immediate application, and meanwhile, an illustrative example is presented.
Adsorption of Naphthalene on Modified Zeolite from Aqueous Solution  [PDF]
Ning Li, Wang-Yu Cheng, Yong-Zhang Pan
Journal of Environmental Protection (JEP) , 2017, DOI: 10.4236/jep.2017.84030
Abstract: In this study, the modified zeolite with certain hydrophobicity was prepared by modifying natural zeolite by the silane coupling agents such as vinyltrimethoxysilane (VTMO), trimethoxysilane (TMS) and trimethylchlorosilane (TMCS). The modified zeolite has a higher hydrophobicity and adsorption capacity than natural zeolite while ensuring the advantages of natural zeolite, which is more conducive to the adsorption of organic pollutants from aqueous solution. The adsorption experiment on naphthalene in aqueous solution shows that the modified zeolite has a stronger adsorption capacity. In the adsorption thermodynamics experiment, the isothermal adsorption models such as Freundlich and Langmuir can better describe the adsorption of naphthalene on modified zeolite, but the isothermal adsorption model Freundlich has a higher correlation. At 303K, the static adsorption capacity is 339μg/g. The kinetic analysis shows that the adsorption of naphthalene on modified zeolite conforms to the quasi-second order kinetic model.
Design of Power Supply for On-line Monitoring System of Transmission Lines  [PDF]
Kai Chen, Zi-jian Zhao, Yu-ning Zhang, Yang-chun Cheng, Yuan Dai
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B109
Abstract:

This paper uses CT to gain the energy directly from the high-voltage transmission line, to address the problem of power supply for monitoring system in high voltage side of transmission line. The draw-out power coil can induce voltage from the transmission line, using single-chip microcomputer to analog and output PMW wave to control the charging module, provides a stable 3.4 V DC voltage to the load, and solve the problem of easy saturating of core. The power supply based on this kind of draw-out power coil has undergone the overall testing, and it is verified-showing that it can properly work in a non-saturated status within the current range of 50 - 1000 A, and provide a stable output. The equipment also design protection circuit to improve the reliability to avid the impacts of the impulse current or short-circuit current. It effectively solves the problem of power supply for On-line Monitoring System of Transmission.

Adaptive Fuzzy Observer Backstepping Control for a Class of Uncertain Nonlinear Systems with Unknown Time-delay

Shao-Cheng Tong Ning Sheng,

国际自动化与计算杂志 , 2010,
Abstract: In this paper, a new adaptive fuzzy backstepping control approach is developed for a class of nonlinear systems with unknown time-delay and unmeasured states. Using fuzzy logic systems to approximate the unknown nonlinear functions, a fuzzy state observer is designed for estimating the unmeasured states. On the basis of the state observer and applying the backstepping technique, an adaptive fuzzy observer control approach is developed. The main features of the proposed adaptive fuzzy control approach not only guarantees that all the signals of the closed-loop system are semiglobally uniformly ultimately bounded, but also contain less adaptation parameters to be updated on-line. Finally, simulation results are provided to show the effectiveness of the proposed approach.
Studies on the switching speed effect of the phase shift keying in SLED for generating high power microwave
Xiong Zhengfeng,Cheng cheng,Yu Jian,Chen Huaibi,Ning Hui
Physics , 2015,
Abstract: SLAC energy doubler (SLED) type radio-frequency pulse compressors are widely used in large-scale particle accelerators for converting long-duration moderate-power input pulse into short-duration high-power output pulse. The phase shift keying (PSK) is one of the key components in SLED pulse compression systems. Performance of the PSK will influence the output characteristics of SLED, such as rise-time of the output pulse, the maximal peak power gain, and the energy efficiency. In this paper, high power microwave source based on power combining and pulse compression of conventional klystrons was introduced, the nonideal PSK with slow switching speed and without power output during the switching process were investigated, the experimental results with nonideal PSK agreed well with the analytical results.
Evidence for the involvement of NGF in human sperm motility  [PDF]
Cui-Ge Shi, Kai Lin, Xiang-Bo Xu, Shu-Cheng Zhang, Ning Wang, Ming Fan
Journal of Biomedical Science and Engineering (JBiSE) , 2012, DOI: 10.4236/jbise.2012.59066
Abstract: Motility is an important physiological characteristic of a mature sperm. Nerve growth factor (NGF) is a key protein for the survival, maintenance and development of the central and peripheral nervous systems. It has been shown that NGF and its receptors TrkA and p75 are widely expressed in the testis, accessory reproductive organ, and the epididymal sperms. These observation have shifted the attention to the role of NGF on male reproductive physiology. In the present study, we found that NGF remarkably increased testicular coefficient in rats subjected to unpredictable chronic mild stress. Furthermore, we investigated the role of NGF on human sperm motility in vitro by CASA. The results showed that the parameters of sperm motility after NGF treatment had significantly increased, the means of VAP, VSL, VCL, BCF and LIN were significantly increased 32% than those of NGF absence, the means of MAD, STR, ALH and WOB had no notable difference. In addition, NGF promotes the sperm motility in a time- and dose-dependent manner. Taken together, our findings suggest that NGF plays a promoted role in sperm motility.
One Case about the Diagnosis and Treatment of Right-Sided Infective Endocarditis without Any Inducement  [PDF]
Shengsen Chen, Kangkang Yu, Qingxia Ling, Chong Huang, Jianming Zheng, Qi Cheng, Mengqi Zhu, Ning Li, Mingquan Chen
Case Reports in Clinical Medicine (CRCM) , 2014, DOI: 10.4236/crcm.2014.312134
Abstract: We present a case of Staphylococcus aurous tricuspid valve endocarditis without any risk factors (intravenous drug users, with pacemaker or central venous lines and with congenital heart disease). Transthoracic echocardiography, as first line examination, showed the vegetations on tricuspid valve. In our case, the diagnosis and treatment of right-sided infective endocarditis without any inducement were extremely difficult. Therefore, once a patient comes out with fever, the blood culture remains positive for gram-positive bacterium, and the infectious location still unknown, then the infective endocarditis should be considered. In addition, surgical measure is also an important therapy for right-sided infective endocarditis.
Meta-Analysis of the Association of HLA-DRB1 with Anti-Citrullinated Protein Antibody-Positive and Anti-Citrullinated Protein Antibody-Negative Rheumatoid Arthritis  [PDF]
Helin Feng, Jianfa Xu, Ning Zhang, Tianshu Gu, Lishi Wang, Cheng Tian, Yan Jiao, Karen Hasty, Weikuan Gu, Qingyi Liu
Open Journal of Immunology (OJI) , 2016, DOI: 10.4236/oji.2016.64013
Abstract: Because of genetic complex and variations of auto antibodies of rheumatoid arthritis (RA) in different populations, the data on the association of HLA-DRB1 alleles in anti-citrullinated protein antibody of (ACPA) RA were inconsistent. The purpose of the study is to systematically summarize results of published data through performing a meta-analysis using data in which HLA-DRB1 alleles are associated with ACPApositive RA and ACPA-negative RA. In this study, we collected data from 12 studies with 13,861 cases and 12,896 controls. Information in these studies included HLADRB1 typing and ACPA status from different countries. Odds ratios (ORs) and corresponding 95% confidence intervals (CI) were used to analyze the association of different HLA-DRB1 alleles with ACPA-positive RA or ACPA-negative RA. To correct skewing data, the analysis of ACPA-status was stratified by patient distribution. Our analyses indicate that in ACPA-positive RA, all patients with RA had significantly higher frequencies of HLA-DRB1*01, *04, *0401, *0405, *07, *11, *13 and *14 than controls. One of the HLA-DRB1*07, *11, *13 and *14 showed protective association with RA. In addition, HLA-DRB1*03, *10 and *12 had more influence than control to RA in European populations; the HLA-DRB1*03 and *12 alleles were associated with the protection. In ACPA-negative RA, only DRB1*07 was associated with the protection (OR 0.53 [95% CI 0.36 - 0.76]) among all HLA-DRB1 alleles in European populations. In ACPA-positive RA, currently available results indicate that *01, *04, *0401 and *0405 are susceptible, while HLA-DRB1*07, *11, *13 and *14 are protective in all populations. While the HLA-DRB1*10 is susceptible, HLA-DRB1*03 and *12 show protective association with RA in European populations. Additionally, regardless of the positive or negative ACPA, the DRB1*07 is always associated with protection in European populations.
Single-Tooth Modeling for 3D Dental Model
Tianran Yuan,Wenhe Liao,Ning Dai,Xiaosheng Cheng,Qing Yu
International Journal of Biomedical Imaging , 2010, DOI: 10.1155/2010/535329
Abstract: An integrated single-tooth modeling scheme is proposed for the 3D dental model acquired by optical digitizers. The cores of the modeling scheme are fusion regions extraction, single tooth shape restoration, and single tooth separation. According to the “valley” shape-like characters of the fusion regions between two adjoining teeth, the regions of the 3D dental model are analyzed and classified based on the minimum curvatures of the surface. The single tooth shape is restored according to the bioinformation along the hole boundary, which is generated after the fusion region being removed. By using the extracted boundary from the blending regions between the teeth and soft tissues as reference, the teeth can be separated from the 3D dental model one by one correctly. Experimental results show that the proposed method can achieve satisfying modeling results with high-degree approximation of the real tooth and meet the requirements of clinical oral medicine. 1. Introduction As the 3D (three dimensional) dental model can be acquired easily through different kinds of intra or extra oral measurement methods including optical digitizers [1–3], CT (CBCT) [4, 5] and MRI [6], CAD (Computer-Aided Design)/CAM (Computer-Aided Manufacturing) has been introduced to dentistry and achieved great success in clinical applications [7–10] such as orthodontics, oral and maxillofacial surgery. Dental restorations can be designed and manufactured much more easily compared with traditional complex and labor-intensive process. Pre- or postsurgery simulation can be used to achieve assessment of dental skeletal relationships and facial aesthetics, audit orthodontic outcomes with regard to soft and hard tissues, and direct 3D treatment planning. In general, the 3D dental models (including 3D single-tooth) used in CAD/CAM dentistry system are mostly obtained by optical digitizers, which is typically represented by using a watertight triangular mesh. The 3D dental model is an integral model without obvious blending boundary between the single-tooth and the soft tissues. Two adjoining teeth sometimes are fused together and without obvious tooth gap, due to teeth overlapping, lower measurement precision, and limited resolution triangulating methods during digitizing step. In order to satisfy the prerequisites of manufacturing the dental restorations and assessing the virtual dental behaviors, the teeth have to be independent of each other and keep the original shape of the real tooth. The accurate single-tooth shape restoration and extraction techniques for the 3D dental model play a
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