丛生稻耐冷性QTL的遗传图谱

本试验研究了一组重组自交系群体的耐冷性QTL，鉴定了水稻耐冷性QTL的染色体区域。自交系群体包括80个品系，它们来源于籼型品种Milyang23与粳型丛生稻Hapcheonaengrni 3间的杂交组合。采用2个形态和132个DNA标记对该组群体进行了基因型分类，还评价了冷水小区和控制小区中与耐冷性状相关的农艺性状。在冷水小区中，重组自交系抽穗推迟，茎秆缩短，而且两个小区间的抽穗期和茎秆差异存在显著的统计学差异。     

偃麦草属种间杂种高代群体的细胞学和育性研究

大偃麦草和山黑麦中，经常利用其双倍体来转移理想性状和恢复种间杂种育性。本试验研究了E.lancelatus、E.caninus、以及其F1杂种、高代材料（F7和F8）和高代双倍体后代的3个世代（C1、C2和C3）的细胞学、育性和形态学特性。E.lancelatus和E.caninus的减数分裂染色体联会为典型的异源四倍体。F1杂种的染色体配对表明这两个亲本间存在密切关系。在F8和F7代中观察到最频繁的二价体联会数为14个二价体。     

Structure of a three-dimensional, microporous molybdenum phosphate with large cavities

The synthesis, single-crystal x-ray structural characterization, and sorption properties of a microporous molybdenum phosphate, (Me(4)N)(1.3)(H(3)O)(0.7)[Mo(4)O(8)(PO(4))(2)] . 2H(2)O (Me, methyl), are presented. The three-dimensional framework is built up from Mo(4)O(8)(4+) cubes and PO(4)(3-) tetrahedra that are connected in such a way that large, cation-filled voids are generated; these voids constitute 25% of the volume of the solid. Absorption isotherms for water show the completely reversible uptake of 4 to 5 percent by weight water into the micropores of this compound, which corresponds to 10 to 12 percent by volume.     

Phase diagram of degenerate exciton systems

Degenerate exciton systems have been produced in quasi-two-dimensional confined areas in semiconductor coupled quantum well structures. We observed contractions of clouds containing tens of thousands of excitons within areas as small as (10 micron)2 near 10 kelvin. The spatial and energy distributions of optically active excitons were determined by measuring photoluminescence as a function of temperature and laser excitation and were used as thermodynamic quantities to construct the phase diagram of the exciton system, which demonstrates the existence of distinct phases. Understanding the formation mechanisms of these degenerate exciton systems can open new opportunities for the realization of Bose-Einstein condensation in the solid state.     

省级农业科学院专利申请与授权调查分析

为了了解我国各省农业科学院的科学研究水平和技术革新状况以及我国农业科学院所从事科学研究的发展动向,本文对全国各省农业科学院申请和授权的各类专利数量和近年来专利申请数的年度变化情况进行了对比分析,并对申请专利的学科分布进行了统计分析,指出了全国农业科学研究院近年来的研究重点及未来需要加大研究力度的学科领域.     

van der waals interactions in the Cl + HD reaction

The van der Waals forces in the entrance valley of the Cl + HD reaction are shown here to play a decisive role in the reaction's dynamics. Exact quantum mechanical calculations of reactive scattering on a potential energy surface without Cl-HD van der Waals forces predict that the HCl and DCl products will be produced almost equally, whereas the same calculations on a new ab initio potential energy surface with van der Waals forces show a strong preference for the production of DCl. This preference is also seen in crossed molecular beam experiments on the reaction. The study of chemical reaction dynamics has now advanced to the stage where even comparatively weak van der Waals interactions can no longer be neglected in calculations of the potential energy surfaces of chemical reactions.     

X-ray microdiffraction images of antiferromagnetic domain evolution in chromium

Magnetic x-ray diffraction combined with x-ray focusing optics was used to image individual antiferromagnetic spin density wave domains in a chromium single crystal at the micron scale. The cross section for nonresonant magnetic x-ray scattering depends on the antiferromagnetic modulation vector and spin polarization direction and allows these quantities to be extracted independently. The technique was used to show that the broadening of the nominally first-order "spin-flip" transition at 123 kelvin, at which the spins rotate by 90 degrees C, originates at the walls between domains with orthogonal modulation vectors. During cooling, the transition begins at these walls and progresses inward. The modulation vector domains are themselves unchanged.     

Synthesis and measurement of ultrafast waveforms from five discrete optical harmonics

Achieving the control of light fields in a manner similar in sophistication to the control of electromagnetic fields in the microwave and radiofrequency regimes has been a major challenge in optical physics research. We manipulated the phase and amplitude of five discrete harmonics spanning the blue to mid-infrared frequencies to produce instantaneous optical fields in the shape of square, sawtooth, and subcycle sine and cosine pulses at a repetition rate of 125 terahertz. Furthermore, we developed an all-optical shaper-assisted linear cross-correlation technique to retrieve these fields and thereby verified their shapes and confirmed the critical role of carrier-envelope phase in Fourier synthesis of optical waveforms.     

Potassium nutrition of maize: Uptake,transport, utilization,and role in stress tolerance

Potassium(K) is an essential macronutrient for plant growth and development and influences yield and quality of agricultural crops. Maize(Zea mays) is one of the most widely distributed crops worldwide. In China, although maize consumes a large amount of K fertilizer, the K uptake/utilization efficiency(KUE)of maize cultivars is relatively low. Elucidation of KUE mechanisms and development of maize cultivars with higher KUE are needed. Maize KUE is determined by K+uptake, transport, and remobili...