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A Movable Mass Spectroscopy Sampling Apparatus for Measuring Spatial Distribution of Neutral Radicals in Silane Plasma

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Chinese Physics Letters 2005年第4期22卷 904-906页

作者：王照奎林揆训林璇英邱桂明祝祖送 DepartmentofPhysics ShantouUniversityShantou515063

movable mass spectroscopy gas sampling apparatus has been established and astraight-line fit of silane depletion fraction f is proposed. The spatial density distributions ofSiHn (n = 0-3) radicals in silane radio frequency glow discharge have been measured by a massspectrometer. The experimental results demonstrate that the densities of the neutral radicals havethe peak value near the middle position of electrodes, and the densities of SiH2 and SiH3 are higherthan those of Si and SiH in silane plasma. This reveals that SiH2 and SiH3 may be the primaryprecursors in forming the a-Si:H film.

关键词： HYDROGENATED AMORPHOUS-SILICON ATOMIC-SCALE ANALYSIS THIN-FILMS PRECURSOR

Low-Temperature Growth of Polycrystalline silicon Films by SiCl4／H2 rf Plasma Enhanced Chemical Vapour Deposition

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Chinese Physics Letters 2003年第10期20卷 1879-1882页

作者：林璇英黄创君林揆训余运鹏余楚迎池凌飞 DepartmentofPhysics ShantouUniversityShantou515063

Polycrystalline silicon film was directly fabricated at 200°C by the conventional plasma enhanced chemical vapour deposition method from SiCl4 with H2 dilution. The crystallization depends strongly on the deposition power. The maximum crystallinity and the crystalline grain size are over 80% and 200-500 nm, respectively. The results of energy dispersive spectroscopy and infrared spectroscopy measurements demonstrate that the film is mostly composed of silicon, without impurities such as Cl, N, C and bonded H. It is suggested that the crystallization at such a low temperature originates from the effects of chlorine, i.e., in-situ chemical, etching, in-situ chemical cleaning, and the detachment of bonded H.

关键词：多晶硅薄膜低温生长 SiCl4/H2 等离子体增强化学气相沉积 PECVD 四氯化硅

Study on the Conformation of Cyclodecapeptide Loloatin C with Obvious Antibiotic Activity

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Chinese Journal of Structural Chemistry 2005年第3期24卷 273-278页

作者：陈河如郭锡坤 SchoolofScience ShantouUniversityShantou515063China

The conformation of cyclodecapeptide loloatin C with obvious antibiotic activity has been investigated in 2,2,2-trifluoroethanol/sodium acetate buffer solution and then characterized by FT-IR, CD and NMR spectrum. The results of FT-IR show that there exists β-strand or β-turn secondary structure in the molecule. According to the CD spectrum, the helical turn is dominant but the β-turn structure also exists. Conformation of the whole molecule is probably a helical β-turn. The chemical shifts and coupling constants prove the existence of a β-structure in the regions of Val1, Orn2 and Leu3. NOESY data and temperature gradients of amide protons suggest that the molecular conformation is a dumbbell-like structure with the waist located between ornithyl (position 2) and D-phenylalanyl (position 7) and β-turn on both ends.

关键词： loloatin C conformation solution conformation cyclopeptides

Fast Growth of Polycrystalline Film in SiCl4／H2 Plasma

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Chinese Physics Letters 2004年第6期21卷 1168-1170页

作者： HUANGRui LINXuan-Ying YUYun-Peng LINKui-Xun WEIJun-Hong YUChu-Ying WANGZhao-Kui DepartmentofPhysics ShantouUniversityShantou515063

We report the discovery of fast growth of polycrystalline silicon films under low temperature of 200-300°C from SiCl4/H2 mixture gases by plasma enhanced chemical vapour deposition technique. The deposition rate strongly depends not only on the rf power and the flow ratio of H2/SiCl4, but also on the substrate temperature, while the crystalline fraction is mainly affected by both the rf power and the flow ratio of H2/SiCl4. The high film-growth rate is due to the enhancement of the gas-phase reaction in SiCl4/H2 plasma. By means of adjusting the matching relation between the flow ratio of H2/SiCl4 and rf power, and optimizing the substrate temperature, we obtain the polycrystalline silicon films deposited at a higher deposition rate over 3.5A/s, with a crystalline fraction of 75% and an average crystallite size of 400-500 nm in diameter.

关键词： Surfaces interfaces and thin films Plasma physics

Formation of Optical Solitons in Nonlinear Photonic Crystal Waveguides

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Chinese Physics Letters 2004年第9期21卷 1762-1765页

作者：兰胜陈雄文 DepartmentofPhysics ShantouUniversityShantou515063

Relying on the huge group velocity dispersion available in photonic crystal (PC) waveguides, we observe the formation of both Bragg grating solitons and gap solitons in nonlinear PC waveguides in numerical experiments. Also, we indicate the potential applications of optical solitons in optical limiting, optical delay, and pulse compression and the feasibility of observing optical solitons in practical experiments.

关键词： Optics quantum optics and lasers

Tolerance of Photonic Crystal Impurity Bands to Disorder of Defects in Coupled Cavity Waveguides

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Chinese Physics Letters 2004年第5期21卷 863-866页

作者：林旭升黄翀欧阳艳东兰胜 DepartmentofPhysics ShantouUniversityGuangdong515063

We investigate the tolerance of photonic crystal impurity bands to the disorder of defects in one-dimensional coupled cavity waveguides. Although impurity bands formed by defect modes close to the air band are quasiflat in the absence of disorder, they are easily deteriorated when disorders are introduced into defects. In contrast, impurity bands created by defect modes near the dielectric band are less sensitive to disorder in the defect size. It is found that the sensitivity of defect mode frequency to defect size and the quality factor of defect modes are two crucial factors in determining the tolerance of impurity bands to the disorder of defects.

关键词： Optics quantum optics and lasers Condensed matter: structural mechanical & thermal

Ecophysiological characteristics of four intertidal marine macroalgae during emersion along Shantou coast of China,with a special reference to the relationship of photosynthesis and CO_(2)

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Acta Oceanologica Sinica 2005年第3期24卷 105-113页

作者： ZOUDinghui GAOKunshan MarineBiologyInstitute ScienceCenterShantouUniversityShantou515063China MarineBiologyInstitute ScienceCenterShantouUniversityShantou515063China／／InstituteofHydrobiologyChineseAcademyofSciencesWuhan430072China

Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents. The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petalonia fascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G. intermedia and S. hemiphyllumexhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia, exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intermedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO2 in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.

关键词： marine macroalgae ecophysiology photosynthesis CO2 zonation

Behaviour of Internal Stress in Melt—Spun Ni—Mn—Ga Ribbons

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Chinese Physics Letters 2003年第3期20卷 427-429页

作者：赵韦人李健靓等 DepartmentofPhysics ShantouUniversityShantou515063 InstituteofFunctionalMaterials CentralIronandSteelResearchInstituteBeijing100081

We investigate the martensitic transition of melt-spun Ni-Mn-Ga ribbons, during which an abrupt release of internal stress occurs. The release results in the appearance of two peaks on the curve of field-induced strains versus temperature. During and after the transformation, a large lag of field-induced strains was observed, indicating a competition between the stress energy and Zeemann energy. The lag leads to an unusual relation of the strains to the inducing field.

关键词： Martensitic transformations

Impacts of Elevated CO2 Concentration on Biochemical Composition, Carbonic Anhydrase, and Nitrate Reductase Activity of Freshwater Green Algae

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Journal of Integrative Plant Biology 2005年第6期47卷 668-675页

作者： Jian-RongXIA Kun-ShanGAO MarineBiologyInstitute ShantouUniversityGuangdong515063China／／InstituteofHydrobiologytheChineseAcademyofSciencesWuhan430072China MarineBiologyInstitute ShantouUniversityGuangdong515063China／／InstituteofHydrobiologytheChineseAcademyofSciencesWuhan430072China

: To investigate the biochemical response of freshwater green algae to elevated CO2 concentrations, Chlorella pyrenoidosa Chick and Chlamydomonas reinhardtii Dang cells were cultured at different CO2 concentrations within the range 3-186 ümol/L and the biochemical composition, carbonic anhydrase (CA), and nitrate reductase activities of the cells were investigated. Chlorophylls (Chl), carotenoids, carbonhydrate, and protein contents were enhanced to varying extents with increasing CO2 concentration from 3-186 ümol/L. The CO2 enrichment significantly increased the Chl a/Chl b ratio in Chlorella pyrenoidosa, but not in Chlamydomonas reinhardtii. The CO2 concentration had significant effects on CA and nitrate reductase activity. Elevating CO2 concentration to 186 ümol/L caused a decline in intracellular and extracellullar CA activity. Nitrate reductase activity, under either light or dark conditions, in C. reinhardtii and C. pyrenoidosa was also significantly decreased with CO2 enrichment. From this study, it can be concluded that CO2 enrichment can affect biochemical composition, CA, and nitrate reductase activity, and that the biochemical response was species dependent.

关键词： carbonic anhydrase Chlamydomonas reinhardtii Chlorella pyrenoidosa CO2 nitrate reductase