Baoding, China
Baoding, China

Hebei University is the only Comprehensive University in Hebei which is directly under Hebei provincial government and the Ministry of Education, China. It's located in Baoding, Hebei Province, China. The university currently has an enrollment of 44,200, including 5500 graduates and 38,700 undergraduates. 169 international students are also studying at the university. Wikipedia.

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Yan H.,Hebei University
Journal of chromatography. A | Year: 2013

Dispersive liquid-liquid microextraction (DLLME) is a modern sample pretreatment technique that is regarded as consilient with the current trends of modern analytical chemistry. DLLME is simple, inexpensive, environmentally friendly, and could offer high enrichment factors from a wide gap between acceptor and donor phases. As a consequence, DLLME has attracted considerable attention from researchers and, based on the numerous publications concerning DLLME, has been generally accepted in separation science since the technique's invention in 2006. However, several innate weaknesses of DLLME, which restrict the technique's use in certain fields, have led to various attempts or suggestions to improve this technique. The present review focuses on the recent advances made in DLLME; the selected papers that are discussed in this work represent modifications that fall into three main categories (exploration of new extraction solvents, disperser solvents and combination with other techniques). The recent applications of DLLME in environmental, food and biological samples are also summarised, covering almost all of the publications related to the technology from the beginning. In addition, the feasibility of future trends of DLLME is discussed. Copyright © 2013 Elsevier B.V. All rights reserved.


Zhang C.,CAS Changchun Institute of Applied Chemistry | Zhang C.,Hebei University | Lin J.,CAS Changchun Institute of Applied Chemistry
Chemical Society Reviews | Year: 2012

Luminescent materials have found a wide variety of applications, including information displays, lighting, X-ray intensification and scintillation, and so on. Therefore, much effort has been devoted to exploring novel luminescent materials so far. In the past decade, defect-related luminescent materials have inspired intensive research efforts in their own right. This kind of luminescent material can be basically classified into silica-based materials, phosphate systems, metal oxides, BCNO phosphors, and carbon-based materials. These materials combine several favourable attributes of traditional commercially available phosphors, which are stable, efficient, and less toxic, being free of the burdens of intrinsic toxicity or elemental scarcity and the need for stringent, intricate, tedious, costly, or inefficient preparation steps. Defect-related luminescent materials can be produced inexpensively and on a large scale by many approaches, such as sol-gel process, hydro(solvo)thermal reaction, hydrolysis methods, and electrochemical methods. This review article highlights the recent advances in the chemical synthesis and luminescent properties of the defect-related materials, together with their control and tuning, and emission mechanisms (solid state physics). We also speculate on their future and discuss potential developments for their applications in lighting and biomedical fields. This journal is © The Royal Society of Chemistry 2012.


Zhang Z.,Hebei University
Information Sciences | Year: 2013

This paper presents a systematic study of interval type-2 fuzzy rough sets integrating rough set theory with interval type-2 fuzzy set theory using constructive and axiomatic approaches. From the perspective of a constructive approach, a pair of lower and upper interval type-2 fuzzy rough approximation operators with respect to an interval type-2 fuzzy relation is defined. The basic properties of the interval type-2 fuzzy rough approximation operators are studied. Using cut sets of interval type-2 fuzzy sets, classical representations of interval type-2 fuzzy rough approximation operators are then presented, and the connections between special interval type-2 fuzzy relations and interval type-2 fuzzy rough approximation operators are investigated. Adopting an axiomatic approach, an operator-oriented characterization of interval type-2 fuzzy rough sets is proposed; in other words, interval type-2 fuzzy rough approximation operators are characterized by axioms. Different axiom sets of interval type-2 fuzzy set-theoretic operators guarantee the existence of different types of interval type-2 fuzzy relations that produce the same operators. Finally, the relationship between interval type-2 fuzzy rough sets and interval type-2 fuzzy topological spaces is examined. We obtain sufficient and necessary conditions for the conjecture that an interval type-2 fuzzy interior (closure) operator derived from an interval type-2 fuzzy topological space can associate with an interval type-2 fuzzy reflexive and transitive relation such that the corresponding lower (upper) interval type-2 fuzzy rough approximation operator is the interval type-2 fuzzy interior (closure) operator. © 2012 Elsevier Inc. All rights reserved.


The hesitant fuzzy set is a useful generalization of the fuzzy set that is designed for situations in which it is difficult to determine the membership of an element to a set owing to ambiguity between a few different values. In this paper, we develop a wide range of hesitant fuzzy power aggregation operators for hesitant fuzzy information. We first introduce several power aggregation operators and then extend these operators to hesitant fuzzy environments, i.e., we introduce operators to aggregate input arguments that take the form of hesitant fuzzy sets. We demonstrate several useful properties of the operators and discuss the relationships between them. The new aggregation operators are utilized to develop techniques for multiple attribute group decision making with hesitant fuzzy information. Finally, some practical examples are provided to illustrate the effectiveness of the proposed techniques. © 2013 Elsevier Inc. All rights reserved.


Zhang Z.,Hebei University
Information Sciences | Year: 2012

Study mainly investigates generalized intuitionistic fuzzy (IF) rough sets based on IF coverings. By using an IF covering, an IF triangular norm, and an IF implicator, two pairs of generalized lower and upper IF rough approximation operators have been constructed, and some fundamental properties are examined. Then, we give some conditions under which the generalized lower IF rough approximation operator is an IF interior operator and the generalized upper IF rough approximation operator is an IF closure operator. Furthermore, the duality of the generalized IF rough approximation operators is discussed. In addition, we propose some concepts and conditions for two intuitionistic coverings to generate an identical lower IF rough approximation operator and an identical upper IF rough approximation operator with the purpose of removing the redundancy in an IF covering. Finally, we compare the IF-neighborhood-oriented IF rough approximation operators with IF-neighborhood-operator-oriented IF rough approximation operators and obtain the conditions under which some or all of these approximation operators are equivalent. © 2012 Elsevier Inc. All rights reserved.


In this paper, we extend the power geometric (PG) operator and the power ordered weighted geometric (POWG) operator [Z.S. Xu, R.R. Yager, Power-geometric operators and their use in group decision making, IEEE Transactions on Fuzzy Systems 18 (2010) 94-105] to Atanassov's intuitionistic fuzzy environments, i.e., we develop a series of generalized Atanassov's intuitionistic fuzzy power geometric operators to aggregate input arguments that are Atanassov's intuitionistic fuzzy numbers (IFNs). Then, we study some desired properties of these aggregation operators and investigate the relationships among these operators. Furthermore, we apply these aggregation operators to develop some methods for multiple attribute group decision making with Atanassov's intuitionistic fuzzy information. Finally, two practical examples are provided to illustrate the proposed methods. © 2013 Elsevier B.V. All rights reserved.


Yang R.-J.,Hebei University
European Physical Journal C | Year: 2011

Recently f(T) theories based on modifications of teleparallel gravity, where torsion is the geometric object describing gravity instead of curvature, have been proposed to explain the present cosmic accelerating expansion. The field equations are always second order, remarkably simpler than f(R) theories. In analogy to the f(R) theory, we consider here three types of f(T) gravity, and find that all of them can give rise to cosmic acceleration with interesting features, respectively. © Springer-Verlag / Società Italiana di Fisica 2011.


Zhang Z.,Hebei University
Knowledge-Based Systems | Year: 2012

In this paper, we present a general framework for the study of interval type-2 rough fuzzy sets by using both constructive and axiomatic approaches. First, several concepts and properties of interval type-2 fuzzy sets are introduced. Then, a pair of lower and upper interval type-2 rough fuzzy approximation operators with respect to a crisp binary relation is proposed. Classical representations of the interval type-2 rough fuzzy approximation operators are then constructed, and the connections between the special binary relations and the interval type-2 rough fuzzy approximation operators are investigated. Furthermore, an operator-oriented characterization of interval type-2 rough fuzzy sets is proposed; that is, interval type-2 rough fuzzy approximation operators are characterized by axioms. Different axiom sets of interval type-2 fuzzy set-theoretic operators guarantee the existence of different types of crisp binary relations, which produce the same operators. Furthermore, the relationship between interval type-2 rough fuzzy sets and interval type-2 fuzzy topological spaces is obtained. The sufficient and necessary condition for the conjecture that an interval type-2 fuzzy interior (closure) operator derived from an interval type-2 fuzzy topological space can be associated with a reflexive and transitive binary relation such that the corresponding lower (upper) interval type-2 rough fuzzy approximation operator is the interval type-2 fuzzy interior (closure) operator is examined. Finally, we provide a practical application to illustrate the usefulness of the interval type-2 rough fuzzy sets model. © 2012 Elsevier B.V. All rights reserved.


Disclosed in the present invention is a protein tyrosine phosphatase inhibitor. The preparation method therefor is: extracting the crude product from the Isaria Fumosorosea Wize solid or liquid fermentation broth using ethyl acetate, ethanol, methanol, or a mixed solvent of chloroform and methanol; separating the obtained extract using column chromatography on silica gel; and obtaining the target product. The inhibitor can be used to prepare pharmaceutical compositions for treating and preventing diabetes, obesity and cancers.


Disclosed in the present invention is a protein tyrosine phosphatase inhibitor. The preparation method therefor is: extracting the crude product from the Isaria Fumosorosea Wize solid or liquid fermentation broth using ethyl acetate, ethanol, methanol, or a mixed solvent of chloroform and methanol; separating the obtained extract using column chromatography on silica gel; and obtaining the target product. The inhibitor can be used to prepare pharmaceutical compositions for treating and preventing diabetes, obesity and cancers.

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