农村劳动力转移给农村发展带来的负向影响——以安徽省为例

在对该省农村劳动力流动现状和农业生产力变化情况分析的基础上,总结出劳动力转移造成农业生产能力减弱、良田撂荒和社会成本增加这三个问题。提出通过建设产业园区和促进农业现代化来缓解这些问题。     

白河林业局红松分布数量预估模型1）

根据长白山地区白河林业局的772块固定标准地调查数据,以及最小二乘法（ OLS）,建立逻辑斯蒂（Logistic）模型来预估该局现时状态有林地的红松分布概率,并采用泊松（Poisson）和负二项分布（Negative binomi-al,NB）模型预估该局现时状态有林地红松的分布数量,并对模型进行了拟合效果评价及独立性检验。结果表明, Logistic模型与数据的拟合效果很好,独立性检验中预测精度也在可接受的范围内,可以利用Logistic模型来预估该局有林地红松的分布概率。与Poisson模型相比,负二项分布模型能够解决因变量的不均匀分布（即过度散布）的问题,因此能够更好地拟合数据。但在独立性检验中,Poisson模型和NB模型的预测精度接近,且都在可接受的范围内,两个模型均可以用来预估该局有林地红松的分布数量。     

一种新型的流媒体系统设计与实现

介绍了一种适用于网络带宽不稳定环境下的高效、可扩展、自适应以及鲁棒性高的视频流压缩与传输技术,并以此为基础最终实现了一个流媒体系统。该系统由流媒体压缩和网络传输控制两部分组成,详细介绍了这两部分所采用的关键技术。     

Cloning and Expression of Gene Responsible for High-Tillering Dwarf Phenotype in Indica Rice Mutant gsor23

High-tillering dwarf mutant gsor23 was generated from an indica rice variety Indica9 radiatied by γ-ray. Genetic analysis showed that this phenotype was controlled by one single recessive gene, which was mapped within a physical distance of 386 kb between two insertion-deletion (InDel) markers C1-WT2 and C1-WT4 on the long arm of chromosome 1. There is a known gene D10 within this region, the mutation of which causes high-tillering in rice. Sequence analysis of the D10 allele in gsor23 revealed that the base cytosine (C) at the 404^th position in the coding region was deleted, which would cause frameshift mutation after the 134^th amino acids. The mutation site and indica background of gsor23 were different from the previously reported japonica mutants d10-1 and d10-2. Therefore, gsor23 is a novel allelic mutant of D10 which encodes the carotenoid-cleaving dioxygenase 8 (CCD8), a key enzyme involved in the biosynthesis of the new plant hormone strigolactones (SLs). After treatment with GR24, a synthetic analogue of SLs, the high-tillering phenotype of gsor23 was restored to normal. Real-time RT-PCR analysis showed that D10 expression was high in roots, but low in leaves. Compared with the wild type Indica9, the expression of the SL biosynthesis gene D10 was upregulated, while genes likely involved in the SL signal transduction pathway such as D3 and D14 were down-regulated in the gsor23 mutant.     

Rooting of Hybrid Clones of Populus tremula L. × P. tremuloides Michx. by Stem Cuttings Derived from Micropropagated Plants

Propagation costs could be cut by replacing part of the micropropagation process with steps involving more traditional techniques. This study explored possibilities for improving existing vegetative propagation techniques for aspen using stem cuttings obtained from micropropagated plants. Vegetative propagation through stem cuttings was studied in 10 micropropagated hybrid aspen clones (Populus tremula L.     

广义系统能量有限的有限制调节器问题的探讨

讨论了广义系统能量有限的有限制调节器问题；通过对广义熵系统(相对不可测子空间)观测状态中的慢状态进行反馈，保证闭环系统正则，得到了在容许初值条件下该问题有解的充要条件。     

犬冠状病毒在犬体内分布的初步研究

对电镜检查粪便中发现有犬冠状病毒的 4只犬 ,进行了血常规、尿常规、肝肾功能和心电图检查 ,均未发现明显异常。扑杀后经电镜负染检查 ,除肠内容物外 ,在其肝、心、脾、肾和肺等实质脏器中均发现冠状病毒粒子     

基于Lyaunov方法的离散时间模糊控制系统设计

研究了基于 T-S模型的离散时间模糊控制器的规则化设计问题。将模糊控制系统看成是一类具有结构式不确定性的系统 ,利用 L ya-punov稳定性定理 ,提出了一类线性状态反馈控制器的规则化设计方法。通过求解离散时间 Lyapunov方程 ,得出线性状态反馈控制律。并给出了保证闭环系统渐近稳定的充分条件     

A System Dynamics Model of Rural Eletrification in Small-Hydroelectric Area

In present paper, a system dynamics model of Rural electrification in small-hydroelectric area was designed by using the principle of system dynamics. The model provides a scientific basis for computer emulation and simulation, and it can be used to analyze the policies on rural electrification.     

关于多项式鲁棒稳定性的几个新结果

本文基于儒歇定理，给出了系数多线性地依赖于不确定参数的多项式鲁棒稳定性的充分条件。这些判据具有简单的形式，十分容易检验。在某些特殊情况下，这些条件甚至还是必要的。本文的结论为具有不确定系数的多项式的鲁棒稳定性提供了一些新的有效的判据。