专题:水科学重大关切问题研究

<正>编者按水是世界中最重要也是最为奇特的物质.由于水的性质都具有反常的特点,水的理论和实验研究自身都极具挑战性,水参与各种物理、地质、化学、生命等过程,水的科学利用关系着人类的命运,水科学研究的重大意义是显而易见的.过去十年来,中国科学院组织相关研究所投入了可观的人力、物力全方位开展水科学研究,取得了一批     

Real-time and label-free detection of biomolecular interactions by oblique-incidence reflectivity difference method

We successfully conduct the label-free and real-time detection of the interactions between epoxy groups and rabbit IgG and 5' CTT CAG GTC ATG AGC CTG AT 3' oligonucleotide, and between the hybridization of 5' CTT CAG GTC ATG AGC CTG AT 3' and its complementary 3' GAA GTC CAG TAC TCG GAC TA 5' oligonucleotide, by the oblique-incidence reflectivity difference (OI-RD) method. The dynamic curves of OI-RD signals, corresponding to the kinetic processes of biomolecular combination or hybridization, are acquired. In our case, the combination of epoxy groups with rabbit IgG and 5' CTT CAG GTC ATG AGC CTG AT 3' oligonucleotide need almost one and a half hours and about two hundred seconds, respectively; and the hybridization of the two oligonucleotides needs about five hundred seconds. The experimental results show that the OI-RD is a promising method for the real-time and label-free detection of biomolecular interactions.     

Simple and universal method in designs of high-efficiency diffractive optical elements for spectrum separation and beam concentration

Diffractive optical elements(DOEs) with spectrum separation and beam concentration(SSBC) functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.     

我国固体物理理论研究的开拓者之一──李荫远教授

编者按１９８９年１０月１７日，中国科学院物理研究所召开了《李荫远先生从事科学研究活动４５周年座谈会》．会上所长杨国帧教授等分别向李荫远教授赠送了纪念品．中国科学院物理学数学部主任章综教授、副主任马大猷教授，中国科学院学部委员洪朝生教授等到会祝贺．现将李荫远教授从事科学研究活动４５年的主要经历和贡献介绍如下，以飨读者．     

Pd OECC薄膜的表面增强拉曼散射

利用较高检测灵敏度的 SERS技术 ,对浓度较低的 Pd OECC吸附在银表面上的薄层在室温下进行了拉曼谱的测量。得到 Pd OECC在强光破坏前后的 SERS光谱。在强光照射下 ,β-胡萝卜素分子的 SERS光谱的散射强度明显降低 ,且线宽增加 ,说明强光照射不但改变了β-胡萝卜素的构象 ,而且也改变了 β-胡萝卜素分子所处的微环境。其结果与强光照射前后吸收光谱的变化相一致。另外 ,没有观察到 Pd OECC薄层与银镜相互作用的其它新振动峰或Pd OECC中其它振动峰峰型的变化 ,可见 Pd OECC在银镜表面保持原来的状态 ,这证明SERS技术在光合作用光破坏机理研究中的可行性     

国际纯粹与应用物理联合会1990年举办的国际会议

C2 符号、单位、命名、原子质量和基本常数委员会 C2.1 第8届国际原子质量和基本常数会议 日期:9月 9日-14日 地址:以色列 耶路撒冷 组织者:Prof、N.Zeldes The Racah Inst.of　Physics Hebrew Unlv.of Jerusalem Jerusalem 91904,ISRAEL C2.2 精密电磁测量会议 日期:6月11日-15日 地址:加拿大 渥太华 组织者:Dr.J.Vanier National　Research Council Ottawa,Ontarir K1A OR6 CANADAC4 宇宙射线委员会 C4.1 第 21届国际宇宙射线会议 日期:1月 6日- 19日 地址:澳大利亚 阿得富德 组织者:Prof.J.R.Prescott Dept.Of Phy. &…     

Design optimization of highly efficient spectrum-splitting and beam-concentrating diffractive optical element for lateral multijunction solar cells

Two improved algorithms are proposed to extend a diffractive optical element （DOE） to work under the broad spec- trum of sunlight. An optimum design has been found for the DOE, with a weighted average optical efficiency of about 6.8% better than that of the previous design. The optimization of designing high optical efficiency DOEs will pave the way for future designs of high-efficiency, low-cost lateral multijunction solar cells based on such a DOE.     

Multiband Terahertz Photonic Band Gaps of Subwavelength Planar Fractals

Optical transmission properties of subwavelength planar fractals in terahertz （THz） frequency regime are studied by means of time-domain spectroscopy. The transmission spectra with multiple pass bands and stop bands are observed. The tunable photonic band gaps are realized by changing the angle between the principle axis of planar fractal and the polarization of THz wave. The possible application of the subwavelength optical component is discussed. We attribute the detected transmittance from subwavelength fractals to localized resonances.     

Pico-second photoelectric characteristic in manganite oxide La0.67Ca0.33MnO3 films

Ultrafast photoelectric characteristic has been observed in La_0.67Ca_0.33MnO₃ films on tilted SrTiO₃ substrates. A pico-second (ps) open-circuit photovoltage of the perovskite manganese oxide films has been obtained when the films were irradiated by a 1.064μm laser pulse of 25 ps duration. The rise time and full width at half-maximum of the photovoltage pulse are ～300 ps and ～700 ps, respectively. The photovoltaic sensitivity was as large as ～500 mV/mJ.     

MgB2超导薄膜的微波测量

报道了利用蓝宝石介质谐振器技术测量MgB2超导薄膜的微波表面电阻Rs、OK时的穿透深度λ(O)和超导能隙△(O)．λ(O)和△(O)的值是通过先测量样品穿透深度λ(T)的变化量△λ(T)，然后由BCS理论模型拟合△λ（T)的实验数据得到的．测试样品是利用化学气相沉积技术在MgO(111)基片上制备的c轴织构的MgB2超导薄膜，薄膜的超导转变温度和转变宽度分别为38K和0．1K．微波测试结果表明在10K，18GHz下MgB2薄膜的Rs约为100μΩ，可以和高质量的YBCO薄膜的Rs值相比拟；BCS理论拟合得到的MgB2超导薄膜的λ(0)=102nm，△(0)：1．13kTc．