Energy Spectra of Anti-nucleons in Finite Nuclei

The quantum vacuum in a many-body system of finite nuclei has been investigated within the relativistic Hartree approach which describes the bound states of nucleons and anti-nucleons consistently. The contributions of the Dirac sea to the source terms of the meson-field equations are taken into account up to the one-nucleon loop and one-meson loop. The tensor couplings for the $\omega$- and $\rho$-meson are included in the model. The overall nucleon spectra of shell-model states are in agreement with the data. The calculated anti-nucleon spectra in the vacuum differ about 20 -- 30 MeV with and without the tensor-coupling effects.Comment: 4 pages, to appear in the Proceedings of MENU 2004 (Beijing, Aug. 29 -- Sept. 4, 2004

Feedback Control of Nuclear Spin Bath of a Single Hole Spin in a Quantum Dot

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Finding Multiple Roots of Nonlinear Equation Systems via a Repulsion-Based Adaptive Differential Evolution

Finding multiple roots of nonlinear equation systems (NESs) in a single run is one of the most important challenges in numerical computation. We tackle this challenging task by combining the strengths of the repulsion technique, diversity preservation mechanism, and adaptive parameter control. First, the repulsion technique motivates the population to find new roots by repulsing the regions surrounding the previously found roots. However, to find as many roots as possible, algorithm designers need to address a key issue: how to maintain the diversity of the population. To this end, the diversity preservation mechanism is integrated into our approach, which consists of the neighborhood mutation and the crowding selection. In addition, we further improve the performance by incorporating the adaptive parameter control. The purpose is to enhance the search ability and remedy the trial-and-error tuning of the parameters of differential evolution (DE) for different problems. By assembling the above three aspects together, we propose a repulsion-based adaptive DE, called RADE, for finding multiple roots of NESs in a single run. To evaluate the performance of RADE, 30 NESs with diverse features are chosen from the literature as the test suite. Experimental results reveal that RADE is able to find multiple roots simultaneously in a single run on all the test problems. Moreover, RADE is capable of providing better results than the compared methods in terms of both root rate and success rate

Cloning and expression of a small heat shock protein gene CaHSP24 from pepper under abiotic stress

The sequence of a small heat shock protein (sHSP) gene CaHSP24 was obtained by homology-based candidate gene method and rapid amplification of cDNA ends (RACE). The cDNA sequence of this gene is 920 bp in size (GenBank: HM132040) and contains an open reading frame (ORF) of 636 bp, which was predicted to encode a protein with 211 amino acid residues. The phylogenetic tree showed that CaHSP24 was quite similar to mitochondrial sHSPs from other plants but was distantly related to sHSPs of pepper cytoplasm and chloroplast. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) showed that CaHSP24 was hardly detectable at 32°C, but accumulated markedly at 40°C. The gene was expressed 0.5 h after exposure to heat stress and the expression reached a peak in 1.5 h; the expression level in heat-resistant cultivar B35 was higher than that in heat-sensitive cultivar B6. The gene was also expressed weakly under salinity, heavy metal, low temperature and oxidative stresses; the expression levels under these conditions were remarkably lower than those under heat stress. Cell viability experiments showed that the heterologous expression of CaHSP24 could enhance the viability of Escherichia coli under heat stress. To sum up, CaHSP24 may play an important role for response to heat stress condition.Key words: Pepper, CaHSP24, heat stress, gene expression

The superheated Melting of Grain Boundary

Based on a model of the melting of Grain Boundary (GB), we discuss the possibility of the existence of superheated GB state. A Molecular Dynamics simulation presented here shows that the superheated GB state can realized in the high symmetric tilt GB. Whether the sizes of liquid nuclei exceed a critical size determined the superheating grain boundary melting or not. Our results also indicate that the increase of melting point due to pressure is smaller than the superheating due to nucleation mechanism.Comment: Accepted by PRB, 7 pages and 5 figure

Study of quasi-distributed optical fiber methane sensors based on laser absorption spectrometry

The coal industry plays an important role in the economic development of China. With the increase of coal mining year by year, coal mine accidents caused by gas explosion also occur frequently, which poses a serious threat to the life safety of absenteeism and national property safety. Therefore, high-precision methane fiber sensor is of great significance to ensure coal mine safety. This paper mainly introduces two kinds of quasi-distributed gas optical fiber sensing systems based on laser absorption spectroscopy. The gas fiber optic sensor based on absorption spectrum has high measurement accuracy, fast response and long service life. One is quasi-distributed optical fiber sensing system based on spatial division multiplexing (SDM) technology and the other is quasi-distributed optical fiber sensing system based on optical time domain reflection and time division multiplexing(TDM) technology