Self-trapping and Self-focusing of Light Beams in Uniaxial Crystals

Ｓｅｌｆ－ｔｒａｐｐｉｎｇａｎｄＳｅｌｆ－ｆｏｃｕｓｉｎｇｏｆＬｉｇｈｔＢｅａｍｓｉｎＵｎｉａｘｉａｌＣｒｙｓｔａｌｓ￥ＧＵＯＱｉ（ＩｎｓｔｉｔｕｔｅｏｆＱｕａｎｔｕｍＥｌｅｃｔｒｏｎｉｃｓ，ＳｏｕｔｈＣｈｉｎａＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｇｕ...     

天然脱氧核糖核酸分子中碱基价键的振动变化

天然脱氧核糖核酸分子中碱基价键的振动变化余多慰，柯惟中（南京师范大学南京２１００９７）ＲａｍａｎＣｈａｒａｃｔｅｒｉｓｔｉｃＡｎａｌｙｓｅｓｏｆＴｈｅＴｗｏＣｏｖａｌｎｅｃｅＢｏｎｄｓｂｙＴｈｅＢａｓｅＳｌｄｅｏｆＧｌｙｃｏｓｉｄｌｃＢｏｎｄｉｎＤＮ...     

New Approach to Investigation of Tunable External Cavity Semiconductor Lasers

ＮｅｗＡｐｐｒｏａｃｈｔｏＩｎｖｅｓｔｉｇａｔｉｏｎｏｆＴｕｎａｂｌｅＥｘｔｅｒｎａｌＣａｖｉｔｙＳｅｍｉｃｏｎｄｕｃｔｏｒＬａｓｅｒｓ￥ＬＵＨｏｎｇｃｈａｎｇ；ＬＵＯＢｉｎ（ＳｏｕｔｈｗｅｓｔＪｉａｏｔｏｎｇＵｎｉｖｅｒｓｉｔｙ，Ｃｈｅｎｇｄｕ６１...     

用同位素替代方法识别化合物ABPO_5(A=Ca,Sr,Ba)的内振动模

用同位素替代方法识别化合物ＡＢＰＯ５（Ａ＝Ｃａ，Ｓｒ，Ｂａ）的内振动模张昊施颖朱恪刘玉龙刘竟青赵铁男梁敬魁（中国科学院物理研究所北京１０００８０）ＶｉｂｒａｔｉｏｎａｌＳｐｅｃｔｒｏｓｃｏｐｙＳｔｕｄｉｅｓｏｆＩｎｔｅｒｎａｌＭｏｄｅｓｏｆＳｔｉｌｗ...     

Dynamic Wavelength Tuning of a Fiber Ring Semiconductor Laser

ＤｙｎａｍｉｃＷａｖｅｌｅｎｇｔｈＴｕｎｉｎｇｏｆａＦｉｂｅｒＲｉｎｇＳｅｍｉｃｏｎｄｕｃｔｏｒＬａｓｅｒＬＵＯＢｉｎＬ¨ＵＨｏｎｇｃｈａｎｇＰＡＮＷｅｉＣＨＥＮＪｉａｎｇｕｏ（ＳｏｕｔｈｗｅｓｔＪｉａｏｔｏｎｇＵｎｉｖｅｒｓｉｔｙ，Ｃｈｅｎｇｄｕ６...     

拉曼光谱在医学上的应用（Ⅱ）

拉曼光谱在医学上的应用（Ⅱ）余国滔（北京大学生命科学学院北京１００８７１）ＢｉｏｍｅｄｉｃａｌＡｐｐｌｉｃａｔｉｏｎｓｏｆＲａｍａｎＳｐｅｃｔｒｏｓｃｏｐｙ（Ⅱ）ＹｕｅＫｗｏｋｔｏ（ＣｏｌｅｇｅｏｆＬｉｆｅＳｃｉｅｎｃｅｓ，ＰｅｋｉｎｇＵｎｉｖｅｒｓ...     

Crostalk in WDM SCM Systems due to SRS

ＣｒｏｓｔａｌｋｉｎＷＤＭＳＣＭＳｙｓｔｅｍｓｄｕｅｔｏＳＲＳＺＨＡＯＬｉａｎｇＸＵＤａｙｏｎｇＷＵＤｅｍｉｎｇＹＵＡＮＨｏｎｇＸＵＡｎｓｈｉ（ＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｏｎｉｃｓ，ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙＮａｔｉｏｎａｌＫｅｙＬ...     

THERMAL INSTABILITY OF D-T BURNING PLASMAS

ＴＨＥＲＭＡＬＩＮＳＴＡＢＩＬＩＴＹＯＦＤ－ＴＢＵＲＮＩＮＧＰＬＡＳＭＡＳ￥Ｂ．Ｒ．ＳＨＩＹ．Ｘ．ＬＯＮＧＨ．Ｇ．ＺＨＡＯ（ＳｏｕｔｈｗｅｓｔｅｒｎｉｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃｓ，Ｐ．Ｏ．Ｂｏｘ４３２，Ｃｈｅｎｇｄｕ６１００４１，Ｓｉｃｈｕａｎ...     

Optical Associative Memory Based on Double Phase Conjugation Using Bi_（12）TiO_（20） Photorefractive Fi

ＯｐｔｉｃａｌＡｓｓｏｃｉａｔｉｖｅＭｅｍｏｒｙＢａｓｅｄｏｎＤｏｕｂｌｅＰｈａｓｅＣｏｎｊｕｇａｔｉｏｎＵｓｉｎｇＢｉ＿（１２）ＴｉＯ＿（２０）ＰｈｏｔｏｒｅｆｒａｃｔｉｖｅＦｉｂｅｒ￥ＬＩＵＳｈｕｔｉａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，...     

Analytic Subject Index to Volume B6,(1997)

ＡｎａｌｙｔｉｃＳｕｂｊｅｃｔＩｎｄｅｘｔｏＶｏｌｕｍｅＢ６，（１９９７）ＬＡＳＥＲＤＥＶＩＣＥＳＮｏ．ＰａｇｅＴｈｅｔｅｍｐｅｒａｔｕｒｅｄｉｓｔｒｉｂｕｔｉｏｎｉｎｌｏｎｇｉｔｕｄｉｎａｌｙｐｕｍｐｅｄＴｉ∶ｓａｐｐｈｉｒｅｌａｓｅｒｓ１１Ｃｈａ...     

红外光谱法研究胆红素在溶液中的结构

本文详细地研究了胆红素在溶液中的结构,得到了很有实用价值的结果。     

An investigation of solid-solid phase transitions in cholesterol and in cholesteryl oleate by positron annihilation

The lifetimes of positrons annihilating in cholesterol and in cholesteryl oleate have been measured as a function of temperature in the vicinity of a previously reported solid-solid transition in each compound. The observed changes in lifetime parameters are discussed in terms of structural changes occurring in these two compounds.     

Multiple electron diffraction and two-dimensional crystalline order in liquid-crystal thin films

Electron diffraction in freestanding thin films in the crystal-B phase reveals extensive multiple diffraction in films of 14S5 but not of 4O.8, suggesting an important difference in the structural order in these films despite the similarities in their positional correlations found in earlier experiments. The result in a two-layer 14S5 film indicates surprisingly that secondary diffraction can occur in a crystal with only pseudo-long-range positional order.     

Size effect in nuclear spin-lattice relaxation and atomic mobility for molten gallium particles

The spin-lattice relaxation rate of gallium isotopes in a melt was shown by NMR to increase considerably with a decrease in gallium particle size. The dominant relaxation mechanism of gallium embedded in an synthetic opal matrix changes from magnetic dipole to electrical quadrupole. The increase in the correlation time of atomic motion in gallium particles with a decrease in their size was estimated. For gallium in opal, the correlation time was found to increase by more than an order of magnitude. It was shown that a variation in atomic mobility becomes noticeable already in gallium particles about 5 μm in size. __________ Translated from Fizika Tverdogo Tela, Vol. 45, No. 12, 2003, pp. 2242–2246. Original Russian Text Copyright ? 2003 by Tien, Charnaya, Sedykh, Kumzerov.     

夏秋两季洱海、太湖表层混合层的深度变化特征及其机理分析

湖泊表层混合层深度的变化不仅影响湖泊水生生态系统的演变, 而且影响流域的局地气候、降水量的时空格局等. 基于2008年夏秋两季洱海(高原湖泊)和太湖(平原湖泊)的气象与水温廓线观测资料, 分析探讨了两湖表层混合层深度的变化特征及其机制. 结果表明: 夏季洱海能维持持续的分层现象, 秋季有明显的日分层现象, 而在相应的两季中, 太湖仅可能存在日分层现象; 洱海表层混合层深度较同期太湖更浅; 太湖两季的表层混合层深度变化较洱海频繁, 即太湖水体混合与分层的交替过程对气象条件的响应较洱海更为迅速. 太湖这类浅水湖泊, 水深是抑制其存在稳定、持续分层的关键因素, 在合适的辐射条件下, 可形成日分层现象; 而洱海这类深度的湖泊, 净热量通量是影响其是否存在持续、稳定分层的主要因子. 该研究为进一步探讨湖泊与大气两种湍流运动的耦合机制及水生生态环境演替规律等提供了有力的参考.     

Spectral Properties of Single BODIPY Dyes in Polystyrene Microspheres and in Solutions

The absorption, fluorescence, fluorescence quantum yield, and photostability of five BODIPY dyes are characterized and compared as single dyes in two environments, in 40-nm polystyrene spheres and in solution. The absorption and fluorescence spectra of the dyes in spheres are similar in profile but shifted to lower energies compared to those in solution. All the dyes are highly fluorescent, with three having fluorescence quantum yields of 1.0. For three of the five dyes, the yields were the same in spheres as in solution (1.00, 1.00, and 0.73). The high concentration of these dyes in spheres does not quench their fluorescence. For two other dyes the yields dropped, from 1.00 to 0.55 in one case and 0.83 to 0.50 in another, comparing the dyes in solution versus in spheres. The photodegradation of the dyes decreases in spheres compared to in solution in all but one case. For one dye, it decreases as much as 800-fold. Dyes overlooked because of low fluorescence or stability in solution could become useful fluorescent materials in the microsphere environment.     

降雨对无线激光通信的影响

通过激光信号在雨介质中传输的实验发现,在大雨环境下,激光信号透射率要比在小雨或微雨的情况下大。这说明光信号在小雨时衰减较大,在大雨时衰减较小。这一现象与人们通常所认为的有所不同。针对降雨对激光信号的影响,根据Mie散射理论和Weibull雨滴尺寸分布模型,分析了不同尺寸的粒子对光的散射作用以及对衰减效率因子的影响,推导出单球粒子对光波的衰减公式,得到了衰减与降雨率的确定关系。通过数值计算发现,与小粒子相比大粒子的前向散射光强更大且更加集中;激光信号在雨介质中传输时,衰减系数在小雨时较大,中雨、大雨时较小,暴雨时不断增大。这一结果与实际情况较吻合,为激光在通信系统中的应用提供了一定的理论依据。     

转小鼠金属硫蛋白(MT)基因烟草不同器官中金属离子铅和锌的分布

转金属硫蛋白(MT)基因植物具有清除重金属污染的能力,但是金属离子在植物体内的分布研究较少。文章以多代培育纯合的转MT烟草为材料,研究了转MT基因烟草积累铅和锌以及铅和锌在不同器官的分布情况。结果表明转基因植株的老叶、茎部和根部铅和锌积累量显著高于普通烟草植株,整株的铅和锌含量分别提高了21.8%和27.2%。铅和锌在植物体内的分布也发生了变化,转基因植株老叶和根中的铅含量分别高出普通烟草同位置的30.2%和47.8%,锌在转基因植株老叶、茎和根中的含量分别高出普通烟草同位置的44.7%,29.2%和21.6%,说明铅更容易在转基因植株老叶和根中积累,而锌更容易在转基因植株的老叶和茎中积累。     

Fiber-optic sensor based on evanescent wave absorbance around 2.7 μm for determining water content in polar organic solvents

The feasibility of sapphire fiber-optic sensors based on evanescent wave absorption spectroscopy in the infrared range for quantitative determination of water content in polar organic solvents has been investigated. Evanescent wave absorption spectra of sapphire fiber-optic sensors in glycerol, ethanol, and glycol with different water concentrations obtained and analyzed, respectively. Evanescent absorbance of the sensors in those organic solvents has been utilized to implement for in situ monitoring water concentration in organic solvents. The evanescent absorbance of sensors in glycerol and glycol has been found to vary linearly with water content in the range 0–30 % and in ethanol in the range 0–10 %, respectively. The fiber-optic sensors based on evanescent absorbance for monitoring water concentrations in those organic solvents are acceptably accurate, cost-effective, and reliable. Some methods to improve the accuracy of predicated water content in those organic solvents are also suggested. Overall, the results demonstrate that the sapphire fiber-optic sensor based on evanescent absorption spectroscopy is a promising candidate for prediction of water content in polar organic solvents in on-line and remote situation.     

Ultrastructural study on dynamics of plastids and mitochondria during microgametogenesis in watermelon

Dynamics of plastids and mitochondria during microgametogenesis in watermelon were examined by means of transmission electron microscopy. Plastids are present as proplastids in the microspore and as amyloplasts in the vegetative cell of the bicellular pollen grain, whereas the generative cell is completely devoid of plastids, suggesting that microspore plastids are excluded from the generative cell during the microspore mitotic division. Therefore, watermelon is classified as Lycopersicon type, where plastids exclusion from the generative cell leads to purely maternal plastid inheritance. Mitochondria in the generative cell show noticeable alterations in size and cristae during microgametogenesis. The diameter of mitochondria is about 0.5 μm in the newly born generative cell, while only about 0.16 μm in the spindle-shaped generative cell. Numerous cristae are present in mitochondria in the spherical generative cell, but, in contrast, mere two or three cristae retain in the spindle-shaped generative cell in the mature pollen grain. In conclusion, the size and cristae number of mitochondria in the generative cell are reduced significantly during microgametogenesis in watermelon.