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Search Results: 1 - 10 of 27940 matches for " Peihua Ma "
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Acid Value Determination and Pre-Esterification of Crude Euphorbia lathyris L. Oil  [PDF]
Qiuyun Zhang, Jinfeng Wu, Peihua Ma, Jie Cai, Yutao Zhang
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.32007
Abstract: There were various problems in the determination of oil acid value of the national standard method, and this paper developed a low cost, simple and effective way to determine the acid value of oil and grease. Furthermore, the esterification of high acid Euphorbia lathyris L. oil (ELO) with methanol could be efficiently catalyzed by hydrochloric acid to produce biodiesel, and the influencing factors such as the amount of catalyst, reaction time, reaction temperature and molar ratio of oil to methanol were also studied. Under the optimized conditions with the oil to methanol molar ratio of 1:30 and a reaction temperature of 70, 95.8% oil conversion was obtained within 40 min in the presence of only 2.0 wt% of catalyst. Therefore, the low-cost non-edible Euphorbia lathyris L. oil as a raw material had good potential for the synthesis of biodiesel in industry.
The Conceptual Model of Influencing Factors and Influencing Mechanism on Team Decision-Making Quality Mediated by Information Sharing  [PDF]
Peihua Dai
iBusiness (IB) , 2013, DOI: 10.4236/ib.2013.54015

Searching for the influencing factors on team decision-making quality is the hot issue in academic circles and business circles. Based on summarizing the main influencing factors on team decision-making quality, this thesis divides the main influencing factors into team composition factors and team process factors and researches the internal relationship between them. Targeted at the field decision making, this thesis analyzes the influencing process of the main factors on decision-making quality, and constructs the conceptual model of “influencing factors-information sharing-decision-making quality”. This model not only combines the main influencing factors correctly, but also exposes the “black box” between the influencing factors and decision-making quality in field decision making, which can make up for no relative research for the field decision making in the previous studies.

Journal of the Chilean Chemical Society , 2010, DOI: 10.4067/S0717-97072010000200006
Abstract: silver embedded lifepo4/c were preparad by direct hydrothermal synthesis of li2co3 feso4 and h3po4 in mixed solution of glucose and ag(nh3)2oh samples were characterized by xrd, sem and galvanostatic charge-discharge test. results show that silver particles are located in the inner part of synthesized diamond-like and rectangular particles. the reversible capacities of prepared samples are 141.3 mah g-1 and no capacity loss are detected after 800 cycles at 1c.
Journal of the Chilean Chemical Society , 2010,
Abstract: Silver embedded LiFePO4/C were preparad by direct hydrothermal synthesis of Li2CO3 FeSO4 and H3PO4 in mixed solution of Glucose and Ag(NH3)2OH Samples were characterized by XRD, SEM and galvanostatic charge-discharge test. Results show that silver particles are located in the inner part of synthesized diamond-like and rectangular particles. The reversible capacities of prepared samples are 141.3 mAh g-1 and no capacity loss are detected after 800 cycles at 1C.
Tensor-SIFT based Earth Mover's Distance for Contour Tracking
Peihua Li
Mathematics , 2010,
Abstract: Contour tracking in adverse environments is a challenging problem due to cluttered background, illumination variation, occlusion, and noise, among others. This paper presents a robust contour tracking method by contributing to some of the key issues involved, including (a) a region functional formulation and its optimization; (b) design of a robust and effective feature; and (c) development of an integrated tracking algorithm. First, we formulate a region functional based on robust Earth Mover's distance (EMD) with kernel density for distribution modeling, and propose a two-phase method for its optimization. In the first phase, letting the candidate contour be fixed, we express EMD as the transportation problem and solve it by the simplex algorithm. Next, using the theory of shape derivative, we make a perturbation analysis of the contour around the best solution to the transportation problem. This leads to a partial differential equation (PDE) that governs the contour evolution. Second, we design a novel and effective feature for tracking applications. We propose a dimensionality reduction method by tensor decomposition, achieving a low-dimensional description of SIFT features called Tensor-SIFT for characterizing local image region properties. Applicable to both color and gray-level images, Tensor-SIFT is very distinctive, insensitive to illumination changes, and noise. Finally, we develop an integrated algorithm that combines various techniques of the simplex algorithm, narrow-band level set and fast marching algorithms. Particularly, we introduce an inter-frame initialization method and a stopping criterion for the termination of PDE iteration. Experiments in challenging image sequences show that the proposed work has promising performance.
Increased intracellular calcium concentration causes electrical turbulence in guinea pig ventricular myocytes
XinRong Fan,JiHua Ma,Wei Wan,PeiHua Zhang,Chao Wang,Lin Wu
Science China Life Sciences , 2011, DOI: 10.1007/s11427-011-4146-1
Abstract: Dysregulation of intracellular Ca2+ homeostasis is associated with various pathological conditions and arrhythmogenesis of the heart. The objective of this study was to investigate the effects of an acute increase in intracellular Ca2+ concentration ([Ca2+]i) on the electrophysiology of ventricular myocytes by mimicking intracellular Ca2+ overload. The [Ca2+]i was clamped to either a controlled (65–100 nmol L 1) or increased (1 μmol L 1) level. The transmembrane action potentials and ionic currents were recorded using whole-cell patch clamp techniques. We found that the acute increase in [Ca2+]i shortened the action potential duration, reduced the action potential amplitude, maximum depolarization velocity and resting membrane potential, caused delayed after-depolarizations (DADs), and triggered activity—compared with these parameters in the control. The increased [Ca2+]i augmented late I Na in a time-dependent manner, reduced I CaL and I K1, and increased I Kr but not I Ks. The results of this study can be used to explain calcium overload-induced ventricular arrhythmias.
Resveratrol Attenuates the Na+-Dependent Intracellular Ca2+ Overload by Inhibiting H2O2-Induced Increase in Late Sodium Current in Ventricular Myocytes
Chunping Qian, Jihua Ma, Peihua Zhang, Antao Luo, Chao Wang, Zhiqiang Ren, Linghao Kong, Shuo Zhang, Xiaojing Wang, Ying Wu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0051358
Abstract: Background/Aims Resveratrol has been demonstrated to be protective in the cardiovascular system. The aim of this study was to assess the effects of resveratrol on hydrogen peroxide (H2O2)-induced increase in late sodium current (INa.L) which augmented the reverse Na+-Ca2+ exchanger current (INCX), and the diastolic intracellular Ca2+ concentration in ventricular myocytes. Methods INa.L, INCX, L-type Ca2+ current (ICa.L) and intracellular Ca2+ properties were determined using whole-cell patch-clamp techniques and dual-excitation fluorescence photomultiplier system (IonOptix), respectively, in rabbit ventricular myocytes. Results Resveratrol (10, 20, 40 and 80 μM) decreased INa.L in myocytes both in the absence and presence of H2O2 (300 μM) in a concentration dependent manner. Ranolazine (3–9 μM) and tetrodotoxin (TTX, 4 μM), INa.L inhibitors, decreased INa.L in cardiomyocytes in the presence of 300 μM H2O2. H2O2 (300 μM) increased the reverse INCX and this increase was significantly attenuated by either 20 μM resveratrol or 4 μM ranolazine or 4 μM TTX. In addition, 10 μM resveratrol and 2 μM TTX significantly depressed the increase by 150 μM H2O2 of the diastolic intracellular Ca2+ fura-2 fluorescence intensity (FFI), fura-fluorescence intensity change (△FFI), maximal velocity of intracellular Ca2+ transient rise and decay. As expected, 2 μM TTX had no effect on ICa.L. Conclusion Resveratrol protects the cardiomyocytes by inhibiting the H2O2-induced augmentation of INa.L.and may contribute to the reduction of ischemia-induced lethal arrhythmias.
Blind Deconvolution for Jump-Preserving Curve Estimation
Xingfang Huang,Peihua Qiu
Mathematical Problems in Engineering , 2010, DOI: 10.1155/2010/350849
Abstract: In many applications, observed signals are contaminated by both random noise and blur. This paper proposes a blind deconvolution procedure for estimating a regression function with possible jumps preserved, by removing both noise and blur when recovering the signals. Our procedure is based on three local linear kernel estimates of the regression function, constructed from observations in a left-side, a right-side, and a two-side neighborhood of a given point, respectively. The estimated function at the given point is then defined by one of the three estimates with the smallest weighted residual sum of squares. To better remove the noise and blur, this estimate can also be updated iteratively. Performance of this procedure is investigated by both simulation and real data examples, from which it can be seen that our procedure performs well in various cases.
Nonparametric estimation of a point-spread function in multivariate problems
Peter Hall,Peihua Qiu
Mathematics , 2007, DOI: 10.1214/009053606000001442
Abstract: The removal of blur from a signal, in the presence of noise, is readily accomplished if the blur can be described in precise mathematical terms. However, there is growing interest in problems where the extent of blur is known only approximately, for example in terms of a blur function which depends on unknown parameters that must be computed from data. More challenging still is the case where no parametric assumptions are made about the blur function. There has been a limited amount of work in this setting, but it invariably relies on iterative methods, sometimes under assumptions that are mathematically convenient but physically unrealistic (e.g., that the operator defined by the blur function has an integrable inverse). In this paper we suggest a direct, noniterative approach to nonparametric, blind restoration of a signal. Our method is based on a new, ridge-based method for deconvolution, and requires only mild restrictions on the blur function. We show that the convergence rate of the method is close to optimal, from some viewpoints, and demonstrate its practical performance by applying it to real images.
Distribution-free cumulative sum control charts using bootstrap-based control limits
Snigdhansu Chatterjee,Peihua Qiu
Statistics , 2009, DOI: 10.1214/08-AOAS197
Abstract: This paper deals with phase II, univariate, statistical process control when a set of in-control data is available, and when both the in-control and out-of-control distributions of the process are unknown. Existing process control techniques typically require substantial knowledge about the in-control and out-of-control distributions of the process, which is often difficult to obtain in practice. We propose (a) using a sequence of control limits for the cumulative sum (CUSUM) control charts, where the control limits are determined by the conditional distribution of the CUSUM statistic given the last time it was zero, and (b) estimating the control limits by bootstrap. Traditionally, the CUSUM control chart uses a single control limit, which is obtained under the assumption that the in-control and out-of-control distributions of the process are Normal. When the normality assumption is not valid, which is often true in applications, the actual in-control average run length, defined to be the expected time duration before the control chart signals a process change, is quite different from the nominal in-control average run length. This limitation is mostly eliminated in the proposed procedure, which is distribution-free and robust against different choices of the in-control and out-of-control distributions.
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