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...     

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

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

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...     

THERMAL INSTABILITY OF D-T BURNING PLASMAS

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

Dynamic Wavelength Tuning of a Fiber Ring Semiconductor Laser

ＤｙｎａｍｉｃＷａｖｅｌｅｎｇｔｈＴｕｎｉｎｇｏｆａＦｉｂｅｒＲｉｎｇＳｅｍｉｃｏｎｄｕｃｔｏｒＬａｓｅｒＬＵＯＢｉｎＬ¨ＵＨｏｎｇｃｈａｎｇＰＡＮＷｅｉＣＨＥＮＪｉａｎｇｕｏ（ＳｏｕｔｈｗｅｓｔＪｉａｏｔｏｎｇＵｎｉｖｅｒｓｉｔｙ，Ｃｈｅｎｇｄｕ６...     

Crostalk in WDM SCM Systems due to SRS

ＣｒｏｓｔａｌｋｉｎＷＤＭＳＣＭＳｙｓｔｅｍｓｄｕｅｔｏＳＲＳＺＨＡＯＬｉａｎｇＸＵＤａｙｏｎｇＷＵＤｅｍｉｎｇＹＵＡＮＨｏｎｇＸＵＡｎｓｈｉ（ＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｏｎｉｃｓ，ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙＮａｔｉｏｎａｌＫｅｙＬ...     

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...     

Analysis of Optical Equalization in WDM System

ＡｎａｌｙｓｉｓｏｆＯｐｔｉｃａｌＥｑｕａｌｉｚａｔｉｏｎｉｎＷＤＭＳｙｓｔｅｍＳＵＮＪｉａｎＧＵＷａｎｙｉＬＩＧｕｏｒｕｉＸＵＤａｘｉｏｎｇ（ＢｅｉｊｉｎｇＵｎｉｖ．ｏｆＰｏｓｔｓ＆Ｔｅｌｅｃｏｍ．，ＢｅｉｊｉｎｇＰ．Ｏ．Ｂｏｘ１２８，Ｃｈｉｎａ...     

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

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

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.     

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。     

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.     

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.     

Spin-1/2 relativistic particle in a magnetic field in NC phase space

This work provides an accurate study of the spin-l/2 relativistic particle in a magnetic field in NC phase space. By detailed calculation we find that the Dirac equation of the relativistic particle in a magnetic field in noncommutative space has similar behaviour to what happens in the Landau problem in commutative space even if an exact map does not exist. By solving the Dirac equation in NC phase space, we not only obtain the energy level of the spin-1/2 relativistic particle in a magnetic field in NC phase space but also explicitly offer some additional terms related to the momentum-momentum non-commutativity.     

Effect of ausforming temperature and strain on the bainitic transformation kinetics of a low carbon boron steel

The effect of ausforming temperature and strain on the bainitic transformation kinetics was investigated in a low carbon boron steel. A new mechanism, which is based on the competition between the increase in nucleation rate and the decrease in average volume of bainite sheaf after deformation, is proposed. The increase in nucleation rate is due to the decrease in boron concentration at the grain boundaries after small deformation and the formation of sub-grain boundaries at the grain interior after large deformation. The decrease in average volume of bainite sheaf is ascribed to the frequent impingement of bainite sub-units after deformation. The increase in nucleation rate after deformation results in the decrease in incubation time, which is confirmed from the experiment. The increase in nucleation rate overcomes the decrease in average volume of bainite sheaf, resulting in the increase in transformation velocity and volume fraction after small deformation. On the contrary, the decrease in the average volume of bainite sheaf overcomes the increase in nucleation rate after large deformation, leading to the decrease in transformation velocity and volume fraction of bainite.     

20世纪后30年中国西北西部降水年代际变化机理分析

在全球气候变暖背景下1980年代中期中国西北西部气候发生了年代际突变,降水明显增加且主要是极端降水的贡献. 本文用欧洲中期预报中心再分析资料ERA-40计算了瞬变涡动、环流、水汽输送及其散度等的年代际变化并进行了分解分析. 结果表明, 1987年后大气环流年代际变化形成"东高西低"环流背景场,西风带向该区的水汽输送增加, 水汽辐合增强,其中主要是定常波水汽输送的贡献, 其结果是造成该区及周边空气水汽含量上升, 有利于降水或极端降水的增加. 夏季该区瞬变涡动增强且造成水汽辐合, 增加了降水天气出现的频率; 冬季瞬变涡动减弱, 天气过程减少, 说明降雪增加的原因应该是空气水汽含量增加, 导致降雪强度增加. 因此该区降水的增加即有中高纬度大气变暖变湿的贡献,也有瞬变涡动的动力作用. 未来西北西部降水的趋势主要取决于瞬变涡动与大气水汽含量变化的竞争．