Starch RVA profile parameters of rice are mainly controlled byWx gene

Quantitative trait locus (QTLs) mapping for rapid visco analyser (RVA) profile parameters has been carried out by using a double haploid (DH) population derhred from a cross betweenindica variety Zhai-Ye-Qing 8 andjaponica variety Jing-Xi 17 and its genetic linkage map. The results indicate that the segregation of the RVA profiles is continually distributed among the DH lines, and some DH lines show transgressive segregation for all the parameters. A major QTL,Waxy (Wx) gene on chromosome 6 which controls the amylose synthesis, has been detected significantly for 5 traits: hot paste viscosity (HPV), cool paste viscosity (CPV), breakdown viscosity (BDV), consistency viscoslty (CSV) and setback viscoslty (SBV). Therefore, the RVA profile parameters are mainly controlled byWx gene. Other 3 and 2 QTLs have also been identified for BDV and SBV, respectively, and two of them share the same region on chromosomes 1 and 5. However, the peak viscosity (PKV) is controlled by a minor QTL on chromosome 12, qPKV-12.     

Crystallization Behavior and Thermal Properties of PP/MgAl LDH Nanocomposites Prepared in Non-polar Solution

Polypropylene(PP)/MgAl layered double hydroxide(MgAl LDH) nanocomposites were synthesized by refluxing PP and dodecyl sulfate-intercalated MgAl LDH[MgAl(DS)] in non-polar xylene. Their structure, thermal and crystallization properties were studied via X-ray diffraction(XRD), transmission electron microscopy(TEM), thermogravimetric analysis(TGA), differential scanning calorimetry(DSC), and polarized light microscopy(PLM). The nanoscaled dispersion of MgAl(DS) nanolayeres in the PP matrix was verified by the disappearance of the d(003) XRD diffraction peak of MgAl(DS) and observation of TEM image. The DSC data show that the SDS/LDH inorganic components negatively affect the crystallization properties of PP and decrease the size of PP spherulites because the inorganic components act as additional nuclei. The PP/MgAl LDH nanocomposites have a faster charring progress in a temperature range of 250―430 °C and a better thermal stability above 320 °C than pure PP.     

Fractal analysis for root growth of plant seedlings under doubled CO2 concentration

Fractal geometry was applied and box dimension was used as an indicator to analyze the effects of doubled CO₂ concentration on the root growth of plant seedlings. Results showed that doubled CO₂ concentration displayed different effects on root branching characteristics of C₃ and C₄ plants. There was an obvious increase of root branches in spring wheat while there were no significant effects on roots of sweet sorghum. In different soil layers, root branching of spring wheat was stimulated and this promotion was most significant in the second layer (10–20 cm), which denoted that elevated CO₂ altered the root branching pattern. That means higher CO₂ concentration influences not only root growth but also its differentiation and development.     

烟草加倍单倍体群体的构建及其在遗传育种中的应用

从花药培养、小孢子培养和子房培养几方面综述了构建烟草DH群体的基本途径及其在遗传育种中的应用和发展动态。     

高功率准连续激光二极管抽运的Q开关内腔倍频固体激光器的研究

对高功率准连续激光二极管抽运的Q开关内腔倍频Nd:YAG和Nd:YVO4激光器进行了实验研究,分别获得了输出功率为3．5W和3．2W,输出波长为532nm的激光脉冲,其重复率达22kHz。     

Simulation study on an improved frequency-doubled triangular-shaped pulse train generator with reduced harmonic distortion

An approach to reducing the harmonic distortion in frequency-doubled triangular-shaped pulse train generation is proposed. It requires a dual-parallel Mach Zehnder modulator followed by a section of dispersive fiber, as the key component. The basic principle is to make the expression of optical intensity approximately equal to the Fourier expansion of idea triangular-shaped waveform. A detailed expression of the final optical intensity is given by theory and then verified by simulation. It is found that the impact of the undesired harmonic distortion is greatlv reduced.     

用于多波长高功率激光能量测量的体吸收能量计

叙述体吸收激光能量计的原理及物理模型，给出其性能参数及测试方法，分析它在神光Ⅱ装置中对三种波长激光能量测量的取样方式及测量精度。     

激光二极管泵浦高效Nd∶YVO_4／KTP腔内倍频激光器

报道了激光二极管泵浦的高转换效率Ｎｄ∶ＹＶＯ４／ＫＴＰ腔内倍频激光器。研究了泵浦光斑尺寸、谐振腔长、ＫＴＰ及Ｎｄ∶ＹＶＯ４的温度对输出绿光效率的影响。在输入泵浦功率为６６９ｍＷ时，获得绿光输出功率１５４ｍＷ，光－光转换效率达２３％。     

Oscillating solitons of the driven,damped nonlinear SchrÖdinger equation

We obtain time-periodic solitons of the parametrically driven, damped nonlinear Schrödinger equation as solutions of the boundary value problem on a two-dimensional domain. We classify the stability and bifurcations of singly and doubly periodic solutions.     

基于YNvd平衡变压器的电铁背靠背SVG补偿系统研究

针对电气化铁道牵引供电系统存在大量的谐波、负序、无功等问题,提出了基于YNvd平衡变压器的背靠背SVG补偿方案。2个SVG通过直流耦合电容背靠背连接在一起,如果两臂的负荷相差较大,中间的直流耦合电容便可以根据负荷的差值进行功率传递,使2个供电臂的负荷基本相同,这样通过平衡变压器将负荷等效到系统一次侧就成为对称负荷,从而解决负序问题。还能兼补牵引负荷引起的谐波和无功问题,达到电能质量的综合治理。通过MATLAB/Simulink仿真,验证了该方案的正确性。