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Zhang Y.,Harbin University
Computational Materials Science | Year: 2017

The bandgap nature and near-edge band structure of the chalcopyrite ZnXP2 (X = Si, Ge, Sn) are investigated using the first-principles approaches. For these materials, whereas the valence band maximums are well defined, there are several competing near-extrema at the conduction band-edge. Moreover, the energetically near-degenerate conduction states are usually derived from different electron orbitals, which results in distinct optical properties and thus different bandgap types. A pseudo-direct bandgap, which is related to a weak optical absorption onset, can also be found beside the well-known direct and indirect bandgaps. In this work, we first investigate the fundamental properties of the band-edge electronic states using the density functional theory with the generalized gradient approximation. The origins of bandgap anomaly of the ZnXP2 systems are then analyzed. Finally, we perform the many-body electronic structure calculations for more reliable band orderings. The quasiparticle calculations indicate that whereas ZnSiP2 and ZnSnP2 have a pseudo-direct and a direct bandgap, respectively. However, ZnGeP2 has a bandgap with mixed pseudo-direct and indirect characters. © 2017 Elsevier B.V.


Liu Z.,Jilin University | Liu Z.,Harbin University
Nonlinear Analysis: Real World Applications | Year: 2013

In this paper, we obtain sufficient criteria for the existence of periodic solutions to deterministic SIR and SEIR epidemic models with modified saturation incidence rates by means of using the continuation theorem based on coincidence degree theory, and we show that the solution is unique and globally stable. Second, we discuss their corresponding stochastic epidemic models with random perturbation have a unique global positive solution respectively, and we utilize stochastic Lyapunov functions to investigate the asymptotic behavior of the solution. © 2012 Elsevier Ltd. All rights reserved.


Rizzolo L.J.,Yale University | Peng S.,Yale University | Peng S.,Harbin University | Luo Y.,Sun Yat Sen University | Xiao W.,Sun Yat Sen University
Progress in Retinal and Eye Research | Year: 2011

The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier by regulating the movement of solutes between the fenestrated capillaries of the choroid and the photoreceptor layer of the retina. Blood-tissue barriers use various mechanisms to accomplish their tasks including membrane pumps, transporters, and channels, transcytosis, metabolic alteration of solutes in transit, and passive but selective diffusion. The last category includes tight junctions, which regulate transepithelial diffusion through the spaces between neighboring cells of the monolayer. Tight junctions are extraordinarily complex structures that are dynamically regulated. Claudins are a family of tight junctional proteins that lend tissue specificity and selectivity to tight junctions. This review discusses how the claudins and tight junctions of the RPE differ from other epithelia and how its functions are modulated by the neural retina. Studies of RPE-retinal interactions during development lend insight into this modulation. Notably, the characteristics of RPE junctions, such as claudin composition, vary among species, which suggests the physiology of the outer retina may also vary. Comparative studies of barrier functions among species should deepen our understanding of how homeostasis is maintained in the outer retina. Stem cells provide a way to extend these studies of RPE-retinal interactions to human RPE. © 2011 Elsevier Ltd.


Zang Z.,University of Shizuoka | Zhang Y.,Harbin University
Applied Optics | Year: 2012

The optical performances of the all-optical switching based on Yb3-doped fiber Bragg grating (FBG) are investigated under the case of self-phase modulation (SPM) and cross-phase modulation (XPM). For the SPM case, the optical bistability of FBG under different parameters is investigated. It shows that the width of the hysteresis loop and threshold switching power are strongly dependent on the fiber grating length, fiber grating detuning, and coupling constant. For the XPM case, the expressions of the threshold switching power in the different detuning range are given. The influence of parameters about different detuning and coupling constant to the threshold switching power and extinction ratio are also studied. In comparison with the SPM case, the switching power of FBG under XPM case can be reduced to less than 20 mW by optimizing the parameters of FBG. © 2012 Optical Society of America.


Lv W.,Harbin University | Yang T.,Harbin Medical University
Clinical Biochemistry | Year: 2012

Objectives: The aim was to investigate the free fatty acid (FFA) metabolic profiles and to identify biomarkers that can be used to distinguish patients with breast cancer (BC) from benign (BE) patients or healthy controls. Design and methods: A total of 114 subjects were divided into the following three groups: BC patients, BE patients and controls. The FFA profiles in three groups were studied by gas chromatography-mass spectrometry coupled with multivariate statistical analysis. Results: Three saturated fatty acids (C14:0, C16:0 and C18:0) and three unsaturated fatty acids (C18:2, C18:3 and C20:5) in BC were significantly different than controls. Palmitic acid, stearic acid, linoleic acid and total FFA were identified as potential biomarkers distinguished BC from the other groups. Conclusion: The alterations of FFA could reflect underlying metabolic changes in BC patients, and this study has demonstrated that FFA biomarkers might be helpful for prevention and characterization of BC patients. © 2011 The Canadian Society of Clinical Chemists.


Zang Z.-G.,Kyushu University | Zhang Y.-J.,Harbin University
Journal of Modern Optics | Year: 2012

We propose a new optical bistable device (OBD), which is constructed by connecting two symmetrical fiber Bragg gratings with a ytterbium-doped fiber to form a nonlinear Fabry-Perot cavity. The principle of this new OBD is described using the transfer-matrix method, and the two groups of transmitted and reflected optical bistability loops under different parameters are investigated symmetrically. Compared with single fiber Bragg grating switching, whose switching power is greater than 2 kW, this new device has evident merits in reducing the switching power to less than 45mW. © 2011 Copyright Taylor and Francis Group, LLC.


Tao L.,Harbin University
Advanced Materials Research | Year: 2011

The adsorption and decolorization of water-soluble azo dye(Eriochrome Black T) was investigated based on eggshell membrane. The effect of adsorption time, pH value, temperature as well as the dosage of eggshell membrane on the decolorization of Eriochrome Black T was studied. It is indicated from the experimental results that the azo-dye adsorption with eggshell membrane should be carried out in acidic solution. At the optimum conditions, 95% of Eriochrome Black T could be removed. In this study, the dumped eggshell membrane can be utilized to solve the pollution problem of dye wastewater, which will offer us a new way for utilization of eggshell membrane and treatment of wastewater. © (2011) Trans Tech Publications.


Li R.,Harbin University
Communications in Computer and Information Science | Year: 2011

In the context of sustainable development theory,the creation of green hotel has become the inevitable trend of hotel industry development.This paper takes green hotel in china as an example,studies on the measures for energy saving, such as adopting advanced technology, green procurement,green room,green food, green service, government's economic policy support, and so on. © 2011 Springer-Verlag Berlin Heidelberg.


Yang N.,Harbin University
Applied Mechanics and Materials | Year: 2014

The integration of Web technology to build collaborative learning environment, and systems analysis of Web technology to support collaborative learning theory, technical infrastructure, integration of Web and the advantages of collaborative learning is proposed mode of Web technology and collaborative learning environment architecture model. Finally, Google cloud computing applications - GoogleApp Engine and Google Apps interpreted as an instance of the Web and cloud computing technology is how to integrate, as well as collaborative learning environment integrated collaborative learning environment, as compared with the traditional strengths lie, and given based on Google Apps web collaborative learning strategies. Web2.0 and demonstrated the feasibility of integrating cloud computing technology, technical support for future research to broaden the thinking and learning. © (2014) Trans Tech Publications, Switzerland.


Yang G.-B.,Harbin University | Sun Z.-H.,Harbin University
Inorganic Chemistry Communications | Year: 2013

Two new metal-organic frameworks, [Zn2(FA)2(bix) 2]n·3nH2O (1) and [Zn(FA)(bib)] n (2), (H2FA = fumaric acid, bix = 4,4′- bis(imidazol-1-ylmethyl)benzene, bib = 1,4-bis(imidazolyl)butane), have been synthesized by combining the fumaric acid and flexible imidazole-based ligands with Zn(II) salts under hydrothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 is a 4-fold interpenetrated unc topological net, and 2 is a 5-fold interpenetrated dia topological net. Moreover, the luminescent properties of the two compounds were also investigated in the solid state at room temperature. © 2012 Elsevier B.V.

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