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Search Results: 1 - 10 of 127852 matches for " Hongwei Li "
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Quantitative analysis of sialic acids in Chinese conventional foods by HPLC-FLD  [PDF]
Hongwei Li, Xingdan Fan
Open Journal of Preventive Medicine (OJPM) , 2014, DOI: 10.4236/ojpm.2014.42009

Background: Sialic acids are a family of ninecarbon sugar compounds with carboxylic acyl derivatives. It exists in bacteria, fish, mammals and other living organisms, participates in and regulates many important life events, such as cell recognition, membrane flow, endocytosis and so on. Sialic acid is usually located in the outermost layer of the sugar part of the cell membrane and the key positions of secreted glycoconjugates (glycolipids, glycoprotein and lipopolysaccharide). Sialic acid (Sia) is an important material foundation for variety of the structure and founction of glycoconjugates. Sia has been known as nearly 50 members, including N-acetylneuraminic acid (Neu5Ac), N-glycoulylneuraminic acid (Neu5Gc) and deaminoneuraminic acid (KDN) as its core monomer. The rest of the sialic acids are derived from these three monomers. The contents of Sia in Chinese food products are unknown. Objective: To determine the contents of Sia in raw and cooked red meat, seafood, poultry and so on. Design: The following food products were purchased from a Chinese supermarket: pork, beef, lamb, salmon, cod, tuna, cow milk, cheese, butter, duck, chicken and chicken eggs. Human milk was collected from Xiamen Maternity and Child Health Care Hospital (Xiamen, China). All tissues were homogenized and hydrolyzed with 0.05 M, 0.1 M and 0.2 M TFA for 150 min at 80°C in dark, respectively. The concentrations of Neu5Ac, Neu5Gc and KDN were determined by using HPLC with fluorescence detector. Results: The contents of total Sia (μg/g tissue or μg/mL liquid sample) in Chinese raw meat were highest in lamb (269.60), followed by pork (254.88), duck (200.63), chicken (162.86) and beef (88.03). The percentages of Neu5Gc were 36.08%, 26.48%, 0%, 0% and 28.40%, respectively. Cod contained higher levels of Sia (171.63) than salmon (104.43) and tuna (77.98). Only Neu5Ac was 50 found in detected aquatic product. Egg yolk contained the highest level of Sia (682.04), and a higher level of Sia (390.67) was found in the egg white. Also our result showed that human milk contained extremely high level of Sia (602.55). Neu5Ac was the predominant form of Sia in all

Research on Control Method of Inverters for Large-scale Grid Connected Photovoltaic Power System  [PDF]
Zhuo Zhang, Hongwei Li
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B284

A grid-connected inverter controlling method to analyze dynamic process of large-scale and grid-connected photovoltaic power station is proposed. The reference values of control variables are composed of maximum power which is the output of the photovoltaic array of the photovoltaic power plant, and power factor specified by dispatching, the control strategy of dynamic feedback linearization is adopted. Nonlinear decoupling controller is designed for realizing decoupling control of active and reactive power. The cascade PI regulation is proposed to avoid inaccurate parameter estimation which generates the system static error. Simulation is carried out based on the simplified power system with large-scale photovoltaic plant modelling, and the power factor, solar radiation strength, and bus fault are considered for the further research. It’s demonstrated that the parameter adjustment of PI controller is simple and convenient, dynamic response of system is transient, and the stability of the inverter control is verified.

A New Filled Function with One Parameter to Solve Global Optimization  [PDF]
Hongwei Lin, Huirong Li
Open Journal of Optimization (OJOp) , 2015, DOI: 10.4236/ojop.2015.41002
Abstract: In this paper, a new filled function with only one parameter is proposed. The main advantages of the new filled function are that it not only can be analyzed easily, but also can be approximated uniformly by a continuously differentiable function. Thus, a minimizer of the proposed filled function can be obtained easily by using a local optimization algorithm. The obtained minimizer is taken as the initial point to minimize the objective function and a better minimizer will be found. By repeating the above processes, we will find a global minimizer at last. The results of numerical experiments show that the new proposed filled function method is effective.
A Sensitive Reversed-Phase High-Performance Liquid Chromatography Method for the Quantitative Determination of Milk Xanthine Oxidase Activity  [PDF]
Zhongqin Li, Ruizhang Guan, Hongwei Liu
Open Journal of Medicinal Chemistry (OJMC) , 2013, DOI: 10.4236/ojmc.2013.31004

A new reversed-phase high performance liquid chromatography method was developed to quantitate the activity of xanthine oxidase involved in milk fat globule membrane with xanthine as the substrate and the separation of product (uric acid). The increment of uric acid in the reaction system was used to calculate the total activity of XO. The optimized assay conditions, linearity of detection, recovery of uric acid and chromatogram were developed in text, indicating this method is simple, rapid and efficient. It is an alternative potential method for the determination of the activity of XO in milk.

A Survey of Distance Metrics for Nominal Attributes
Chaoqun Li,Hongwei Li
Journal of Software , 2010, DOI: 10.4304/jsw.5.11.1262-1269
Abstract: Many distance-related algorithms, such as k-nearest neighbor learning algorithms, locally weighted learning algorithms etc, depend upon a good distance metric to be successful. In this kind of algorithms, a key problem is how to measure the distance between each pair of instances. In this paper, we provide a survey on distance metrics for nominal attributes, including some basic distance metrics and their improvements based on attribute weighting and attribute selection. The experimental results on the whole 36 UCI datasets published on the main web site of Weka platform validate their effectiveness.
Exact number of chord diagrams and an estimation of the number of spine diagrams of ordern
Banghe Li,Hongwei Sun
Chinese Science Bulletin , 1997, DOI: 10.1007/BF03186960
Abstract: As a byproduct, an upper bound is obtained, for the dimension of Vassiliev knot invariants of ordern, that is, 1/2(n 1)! for anyn≥3, and 1/2 (n 1)! 1/2 (n 2)! for biggern. Our upper bound is based on the work of Chmutov and Duzhin and is an improvement of their bound (n 1)!. Forn = 3, and 4, 1/2(n 1)! is already the best.
A few questions on the support function of the discussion in the teaching of convex analysis
Weiguo Li,Hongwei Zhang
International Mathematical Forum , 2012,
A Comparison Study on the Rhetorical Moves of Abstracts in Published Research Articles and Master’s Foreign-language Theses
Hongwei Ren,Yuying Li
English Language Teaching , 2011, DOI: 10.5539/elt.v4n1p162
Abstract: The abstract of research papers is one of the first things that a reader will read to determine the value of the research. A well-written abstract will surely promote the text attached to it more effectively. By examining the rhetorical moves in the abstracts of Chinese Master’s English theses and published research articles in applied linguistics, this study compares the practices of student writers and expert writers in fulfilling the rhetorical goal of abstracts to shed light on the degree to which students appropriate to the practices of their own discipline and to provide relevant ESP materials for both teachers and student writers of applied linguistics, especially those who write in English as a foreign language.
The Application of Lateral Inhibition Model in Image's Contour Enhancement and Design of Its Electro-Model
Hongwei Fu,Dongguang Li
Journal of Multimedia , 2009, DOI: 10.4304/jmm.4.6.333-340
Abstract: For overcoming the problems such as distortion and shift of object’s edge, easily losing the object detail information of methods in image edge detection, and satisfying higher demand for object detection in the modern war, a new image edge detection method was designed. LOG edge detection as a typical image processing method was introduced and the disadvantage of this model was analyzed firstly. Based on lateral inhibition theory, an acyclic lateral inhibition network model (ALINM) based on biology vision information processing mechanism was designed. The feasibility of object detection by lateral inhibition model was analyzed, in order to express the advantage such as rapid calculation easily real time operation of ALINM, the calculation magnitude of circulation difference lateral inhibition model was analyzed. Besides the correctness of ALINM was confirmed with two input cells, its transfer function was deduced. An algorithm of image edge detection based on this model was established finally, lateral inhibition effect also was confirmed by one-dimension
Cesari-type Conditions for Semilinear Elliptic Equations with Leading Term Containing Controls
Bo Li,Hongwei Lou
Mathematics , 2010,
Abstract: An optimal control problem governed by semilinear elliptic partial differential equations is considered. The equation is in divergence form with the leading term containing controls. By studying the $G$-closure of the leading term, an existence result is established under a Cesari-type condition.
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