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81.
Previously we have selected wild sugarcane (Saccharum spontaneum L.) sterile lines that are tolerant or susceptible to UV-B radiation based on response index (RI) in a field screening test. The RI was established according to plant height, tiller number, leaf index, total biomass and brix under enhanced ultraviolet-B (UV-B, 280-310 nm) radiation. In this experiment, molecular markers linked to the UV-B tolerant and susceptible genes were identified and cloned. RAPD (Randomly amplified polymorphic DNAs) assay using 100 arbitrary primers followed by clustering analysis separated the tolerant and susceptible lines into two groups at the genetic distance of 0.380. The UV-B tolerant and susceptible gene pools were constructed and compared using the Bulked Segregate Analysis (BSA) approach. Of the 100 arbitrary RAPD primers, primer OPR16 produced polymorphic DNA banding patterns from both gene pools. The OPR16-1200 bp DNA fragment was only amplified from the tolerant lines and the OPR16-800 bp from the susceptible ones. These two PCR fragments were cloned onto T-vector. DNA sequence alignment analysis determined that 42% homology existed between the reverse and forward sequences of the OPR16-1200 bp clone, and 36% homology between the forward sequences of the OPR16-800 bp and OPR16-1200 bp clones. The two DNA clones were determined to be linked to the UV-B tolerant and susceptible genes, and they can be used to develop molecular markers for the associated traits. 相似文献
82.
Ma CH Liu TT Yang L Zu YG Chen X Zhang L Zhang Y Zhao C 《Journal of chromatography. A》2011,1218(48):8573-8580
Ionic liquid-based microwave-assisted extraction (ILMAE) has been successfully applied in extracting essential oil and four kinds of biphenyl cyclooctene lignans from Schisandra chinensis Baill. 0.25 M 1-lauryl-3-methylimidazolium bromide ionic liquid is selected as solvent. The optimum parameters of dealing with 25.0 g sample are 385 W irradiation power, 40 min microwave extraction time and 1:12 solid-liquid ratio. The yields of essential oil and lignans are 12.12±0.37 ml/kg and 250.2±38.2 mg/kg under the optimum conditions. The composition of the essential oil extracted by hydro-distillation, steam-distillation and ILMAE is analyzed by GC-MS. With ILMAE method, the energy consumption time has not only been shortened to 40 min (hydro-distillation 3.0 h for extracting essential oil and reflux extraction 4.0 h for extracting lignans, respectively), but also the extraction efficiency has been improved (extraction of lignans and distillation of essential oil at the same time) and reduces the environmental pollution. S. chinensis materials treated by different methods are observed by scanning electronic microscopy. Micrographs provide more evidence to prove that ILMAE is a better and faster method. The experimental results also indicate that ILMAE is a simple and efficient technique for sample preparation. 相似文献
83.
Xian Zu Lin 《数学学报(英文版)》2011,27(5):863-870
Let G/P be a homogenous space with G a compact connected Lie group and P a connected subgroup of G of equal rank. As the rational cohomology ring of G/P is concentrated in even dimensions, for an integer k we can define the Adams map of type k to be l
k
: H*(G/P, ℚ) → H*(G/P, ℚ), l
k
(u) = k
i
u, u ∈ H
2i
(G/P, ℚ). We show that if k is prime to the order of the Weyl group of G, then l
k
can be induced by a self map of G/P. We also obtain results which imply the condition that k is prime to the order of the Weyl group of G is necessary. 相似文献
84.
Zu‐Shun Xu Zi‐Wei Deng Xiao‐Xi Hu Lei Li Chang‐Feng Yi 《Journal of polymer science. Part A, Polymer chemistry》2005,43(11):2368-2376
Monodisperse polystyrene microspheres with diameters of 200–500 nm were prepared by dispersion polymerization with microwave irradiation with poly(N‐vinylpyrrolidone) as a steric stabilizer and 2,2′‐azobisisobutyronitrile as a radical initiator in an ethanol/water medium. The morphology, size, and size distribution of the polystyrene microspheres were characterized with transmission electron microscopy and photon correlation spectroscopy, and the formed films of the polystyrene dispersions were characterized with atomic force microscopy. The effects of the monomer concentration, stabilizer concentration, and initiator concentration on the size and size distribution of the polystyrene microspheres were investigated. The polystyrene microspheres prepared by dispersion polymerization with microwave irradiation were smaller, more uniform, and steadier than those obtained with conventional heating. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2368‐2376, 2005 相似文献
85.
VALUE-AT-RISK的核估计理论 总被引:5,自引:0,他引:5
如何根据历史数据估计Value-at-Risk(VaR);是风险分析与管理中一个重要的基本问题.木文基于非参数核估计方法,通过拟合实际数据过程的分布,构造了VaR的估计.在合适的相依数据条件下,证明了该估计量的渐近正态性,并给出了渐近方差的估计.由此表明:本文所构造的估计量不仅比参数模型具有更广泛的适应性,而且如同参数模型具有n~(-1/2)的收敛速度.本文假设的数据过程避免使用混合性,可很好地适用于金融管理中广泛应用的ARMA与GARCH模型族及非线性模型. 相似文献
86.
讨论了目前有关22Na(p,γ)23Mg反应的实验研究工作,结合兰州放射性束流线上的放射性束流23Al的β+延发质子衰变实验的测量结果,给出了23Al延发衰变的质子能谱,并比较了近期实验给出的相关能级的自旋、宇称值,正是由于这种自旋、宇称和能级部分宽度的不确定性,导致了反应率计算的不确定性.计算了同位旋相似态的共振强度.对于测量到的新的延发衰变能级Ed=8.916MeV,由于没有相应的能级宽度值,实验仅给出其相对共振强度值. 相似文献
87.
IrnmobilisedaIninoacylaseisanotablecatalystforthekineticresolutionofN-acetyl-D,L-aIninoacidsandquitealotofresearchworkhasbeeninvolvedonaminoacylase~bilisationswithitscarriers.lTheauthorshaverePortedthattheaIninosilicagelspreparedbyanlinProvedmethodwereeffechveforchymotryPsininunobilisahon,'l'butitwasnotproperforaIninoacylasetriobilisahon.InordertodevelopasahsfactorysurfacesmictUreofsilicagelsforaIninoacylasetriobilisation,tWokindsofreactivegrouPs,theN,N-diethylaIninogrouPandthehydroxygr… 相似文献
88.
研究具有耦合二次型随机性能指标的离散时间大种群随机多智能体系统的分散博弈问题.系统所受的噪声干扰为条件二阶矩有界的鞅差序列,比以往研究所考虑的高斯白噪声情形更具有广泛性.采用状态聚集方法构造了对种群状态平均的估计,基于Nash必然等价原理设计了分散控制律,并利用概率极限理论分析了闭环系统的稳定性和最优性.主要结果包括(1)证明了对种群状态的平均的估计在某种范数意义下的强一致性,即种群状态的平均与其估计值之间的误差在该范数意义下将随系统个体数N的增加几乎必然收敛于0;(2)证明了闭环系统的几乎必然一致稳定性,即系统的稳定性与种群个体数N无关;(3)证明了所设计的分散控制律是几乎必然渐近Nash均衡策略. 相似文献
89.
90.
Multiplicity of positive periodic solutions to superlinear repulsive singular equations 总被引:1,自引:0,他引:1
In this paper, we study positive periodic solutions to the repulsive singular perturbations of the Hill equations. It is proved that such a perturbation problem has at least two positive periodic solutions when the anti-maximum principle holds for the Hill operator and the perturbation is superlinear at infinity. The proof relies on a nonlinear alternative of Leray-Schauder type and on Krasnoselskii fixed point theorem on compression and expansion of cones. 相似文献