Wyniki wyszukiwania - Biblioteka Nauki

1

Anderson Localization in Quantum Chaos: Scaling and Universality

100%

García-García A. , Wang J.

Acta Physica Polonica A

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2007

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tom 112

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nr 4

635-653

EN

The one-parameter scaling theory is a powerful tool to investigate Anderson localization effects in disordered systems. In this paper we show that this theory can be adapted to the context of quantum chaos provided that the classical phase space is homogeneous, not mixed. The localization problem in this case is defined in momentum, not in real space. We then employ the one-parameter scaling theory to: (a) propose a precise characterization of the type of classical dynamics related to the Wigner-Dyson and Poisson statistics which also predicts in which situations Anderson localization corrections invalidate the relation between classical chaos and random matrix theory encoded in the Bohigas-Giannoni-Schmit conjecture, (b) to identify the universality class associated with the metal-insulator transition in quantum chaos. In low dimensions it is characterized by classical superdiffusion, in higher dimensions it has in general a quantum origin as in the case of disordered systems. We illustrate these two cases by studying 1d kicked rotors with non-analytical potentials and a 3d kicked rotor with a smooth potential.

2

Study on Fluorescence Characteristic of a Complex Probe οf CdSe Quantum Dots Coupling with Thiazole Orange

80%

Fei X. , Jia G. , Wang J. , Gu Y.

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tom 117

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nr 6

949-952

EN

CdSe quantum dots were synthesized using thioglycolic acid as stabilizer in aqueous solution under N_{2}. The UV-vis spectrometry and fluorescence spectra indicate that the bimodal quantum dots were formed and the optical band gaps are about 650 nm and 750 nm, respectively. The quantum dots coated with TO were prepared in room temperature, and the fluorescence characteristic was studied. The result showed that the peak shift of quantum dots fluorescence spectra can mainly be due to the change of the capping layer, resulting in the confinement energy change. This is vital for the investigating on of the forming process and mechanisms of the combination of thiazole orange dye and quantum dots.

3

Intrinsic Rhythmic Fluctuation of Membrane Voltage Evoked by Membrane Noise in the Hodgkin-Huxley System

80%

Kuang S. , Wang J. , Zeng T.

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tom 117

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nr 3

435-438

EN

We study the influence of membrane noise on the fluctuations of membrane voltage in the Hodgkin-Huxley neuronal system for the giant axon of squids. We find that the resting potentials of membrane patches in the absence of any external stimulus, exhibit apparent rhythmic fluctuation behaviors. The intrinsic fluctuation frequencies of membrane voltage, due to channel noise, thermal noise, or both, roughly share the same frequency ranges, despite that the fluctuations arisen from the former noise are overwhelmingly larger in amplitude than that from the latter. We also show that the rhythmic fluctuations can help enhance the encoding of weak signals within the rhythmic frequencies ranges and thus contribute positively to the information processing in the nervous system.

4

Structural and Optical Properties of ZnO Nanowires Doped with Magnesium

70%

Zhuang H. , Wang J. , Liu H. , Li J. , Xu P.

Acta Physica Polonica A

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2011

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tom 119

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nr 6

819-823

EN

ZnO nanowires doped with Mg have been successfully prepared on Au-coated Si (111) substrates using chemical vapor deposition method with a mixture of ZnO, Mg, and activated carbon powders as reactants at 850°C. The structural, compositional, morphological and optical properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. The nanowires are single crystalline in nature and preferentially grow up along [0001] direction with the average diameter and length of about 60 nm and several hundred micrometers, respectively, thinner and longer than the results of literature using the similar method. Room temperature photoluminescence spectroscopy shows a blueshift from the bulk band gap emission, which can be attributed to Mg doping that were detected by energy dispersive X-ray analysis EDX in the nanowires. Finally, the possible growth mechanism of crystalline ZnO nanowires is discussed briefly.

5

Opiate abuse, innate immunity, and bacterial infectious diseases

70%

Wang J. , Barke R. A. , Ma J. , Charboneau R. , Roy S.

Archivum Immunologiae et Therapiae Experimentalis

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2008

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tom 56

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nr 5

299-309

EN

The first line of defense against invading bacteria is provided by the innate immune system. Morphine and other opiates can immediately disrupt the body's first line of defense against harmful external bacteria. Opiate, for example morphine, abuse degrades physical and physiologic barriers, and modulates phagocytic cells (macrophages, neutrophils) and, nonspecific cytotoxic T cells (gd T), natural killer cells, and dendritic cells, that are functionally important for carrying out a rapid immune reaction to invading pathogens. In vitro studies with innate immune cells from experimental animals and humans and in vivo studies with animal models have shown that opiate abuse impairs innate immunity and is responsible for increased susceptibility to bacterial infection. However, to better understand the complex interactions between opiates, innate immunity, and bacterial infection and develop novel approaches to treat and even prevent bacterial infection in the opiate-abuse population, there is an urgent need to fill the numerous gaps in our understanding of the cellular and molecular mechanisms by which opiate abuse increases susceptibility to bacterial infection.

6

Synchronization Study and Introductory Experiment οf Laser-Triggered Surface Flashover in Voltage Pulse

61%

Pan R. , Wang J. , Sun Y. , Sun G. , Yan P. , Zhang D.

Acta Physica Polonica A

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2009

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tom 115

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nr 6

1167-1169

EN

With the aim of studying the characteristics of laser-triggered surface flashover in voltage pulse, synchronization problem of laser pulse and voltage pulse should be solved. A single/double harmonic, with wavelength λ of 1064/532 nm, Q-switched Nd:YAG laser is used to trigger the surface flashover. The synchronization problem is solved using a self-made digital delay/pulse generator. The delay time and jitter of Marx's trigger input and output, Marx's trigger output and Marx's output, laser input and output are respectively measured. Based on the result of the delay time and the timing sequence of the laser triggering system, the synchronization of laser pulse and voltage pulse is obtained through adjusting the channel delay time of digital delay/pulse generator. In addition, introductory experiment of laser-triggered surface flashover is carried out using the flat electrodes and columned insulators.

7

Characteristics of Magnetic Core in Magnetic Pulse Compression System

61%

Zhang D. , Yan P. , Sun Y. , Wang J. , Zhou Y. , Pan R.

Acta Physica Polonica A

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2009

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tom 115

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nr 6

1001-1003

EN

In order to obtain the characteristics of magnetic core under ≈0.5-5 μs saturation time, a one-stage magnetic pulse compression circuit without external demagnetization circuits which are commonly used in magnetic compressors is designed. The current through the core is calculated by voltage across the resistive load, and the loop voltage is picked up with a single wire loop and integrated by software. B-H curves are derived from the measured voltage and current wave forms. B-H curves show that the core loss is in inverse proportion to the time to saturation, whereas the percentile core loss decreases as the charging energy increases. While the eddy current loss and dissipated energy are in direct proportion to dB/dt. The low inductance of magnetic switch indicates that the core is saturated and behaves as an air core. By applying custom characteristics to each stage in Pspice simulation, more practical energy transfer in magnetic pulse compression and the effects of leakage current are presented.

8

A direct comparison of rejection by CD8 and CD4 T cells in a transgenic model of allotransplantation

51%

Porrett P. M. , Lee I. M. K. , Lian M. M. , Wang J. , Caton A. J. , Deng S. , Markmann J. E. , Moore D. J.

Archivum Immunologiae et Therapiae Experimentalis

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2008

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tom 56

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nr 3

192-200

EN

Introduction: The relative contributions of CD4+ and CD8+ T cells to transplant rejection remains unknown. The authors integrated a previous model of CD4-mediated graft rejection with a complementary model of CD8-mediated rejection to directly compare the function of graft-reactive CD4+ and CD8+ lymphocytes in vivo in a model where rejection requires transgenic T cells. These studies allow direct comparison of CD4 and CD8 T cell responses to the same antigen without the confounding effects of T cell depletion or homeostatic proliferation. Materials and Methods: Clone 4 and TS1 mice possess MHC class I- and II-restricted CD8+ and CD4+ T cells, respectively, which express transgenic T cell receptors that recognize the influenza hemagglutinin antigen (HA). We compared the in vivo response of CFSE-labeled, HA-specific transgenic CD8+ and CD4+ T cells after adoptive transfer into syngeneic BALB/c mice grafted with HA-expressing skin. Results: As in the authors' CD4+ model, HA104 skin was consistently rejected by both Clone 4 mice (n=9, MST: 14.2) and by 5x105 Clone 4 lymphocytes transferred to naive BALB/c hosts that do not otherwise reject HA+ grafts. Rejection correlated with extensive proliferation of either graft-reactive T cell subset in the draining lymph nodes, and antigen-specific CD4+ and CD8+ cells acquired effector function and proliferated with similar kinetics.Conclusions: These data extend the authors' unique transgenic transplantation model to the investigation of CD8 T cell function. The initial results confirm fundamental functional similarity between the CD4 and CD8 T cell subsets and provide insight into the considerable redundancy underlying T cell mechanisms mediating allograft rejection.

9

Development of a 20 kJ Sparker for High Resolution Ocean Seismic Survey

51%

Sun Y. , Gao Y. , Yan P. , Wang J. , Yuan W. , Wu H. , Wang Y. , Wan P. , Zhao G.

Acta Physica Polonica A

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2009

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tom 115

|

nr 6

1059-1061

EN

An ocean sparker with a stored energy of 20 kJ was developed for high resolution ocean seismic survey. The sparker is mainly composed of a high voltage high frequency charging supply, energy storage capacitors, a discharging switch and discharging electrodes. The H-bridge inverter and series resonant mode were adopted in the charging supply, and a dry high voltage transformer was used to improve the safety and maintenance, the average charging rate exceeded 4 kJ/s. An optical fiber connected between the high voltage system and the control system was used to isolate high voltage and transmit the high voltage signal. The high voltage electrodes of the discharging electrodes consisted of several hundreds of electrodes. The experimental results show that the sparker can be operated at repetition rates of 12 shots/min, and can meet the expected design requirements. Further field tests will be done in the near future.

10

Theoretical Analysis of the TE Mode Cerenkov Type Second Harmonic Generation in Ion-Implanted X-Cut Lithium Niobate Planar Waveguides

51%

Du G. , Li G. , Zhao S. , Qiao W. , Yang K. , An J. , Li M. , Wang J. , Wang W.

Acta Physica Polonica A

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2009

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tom 115

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nr 3

685-689

EN

We present a study of the Cerenkov configuration second harmonic generation in X-cut ion-implanted lithium niobate waveguides. An approximate solution of conversion efficiency is given and plotted which shows that it is very sensitive to the waveguide depth and pump wavelength. The results can be used in the design of waveguides for the efficient second harmonic generation in the Cerenkov configuration.

11

Novel 12-bp deletion in the coding region of the bovine NPM1 gene affects growth traits

41%

Huang Y.-Z. , Zhang E.-P. , Chen H. , Wang J. , Li Z.-J. , Huai Y.-T. , Ma L. , Lan X.-Y. , Ren G. , Lei C.-Z. , Fang X.-T. , Wang J.-Q.

Journal of Applied Genetics

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2010

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tom 51

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nr 2

199-202

EN

The nucleophosmin 1 gene (NPM1) encodes a multifunctional nucleolar phosphoprotein that plays a crucial role in the control of various aspects of cell growth and homeostasis. In this study, the coding region of the NPM1 gene was screened in 1035 individuals of 4 Chinese cattle breeds by DNA sequencing and polyacrylamide gel electrophoresis. A novel 12-bp deletion mutation was identified in the coding region of the NPM1 gene. The PCR products of primer NPM1-P2 exhibited 3 genotypes and 2 alleles: 178 bp (denoted as W) and 166 bp (denoted as D). Genotype DD and allele D were predominant in the studied populations. Association analysis with growth traits in the Nanyang breed (N = 265) showed that the animals with genotype DD had significantly greater birth weight, body weight, body length, and heart girth than those with genotype WD (P < 0.01 or P < 0.05) at birth and after 6 months and 12 months, but not at 18 and 24 months of age. Results of this study suggest that the NPM1 gene is a candidate gene for growth traits in cattle.