新生代农民工工作满意度实证分析——基于结构方程模型的研究

基于成都市266个新生代农民工的调查数据,建立了农民工工作满意度高阶测量结构方程模型(HCFA)。研究结果表明:报酬待遇对新生代农民工工作满意度的解释能力下降,劳动时间安排、工作环境的解释能力上升,社会保障的解释能力最差,反映出新生代农民工对报酬待遇的关注降低,对劳动时间安排、工作环境等的关注加强,而对社会保障的关注程度最低。     

60Co-γ射线辐射马铃薯块茎M2代群体的诱变效应

[目的]研究60Co-γ射线的不同辐射剂量对马铃薯块茎M2代群体的诱变效应。[方法]以云薯2号和鄂马铃薯5号为试材,采用60Co-γ射线的4种辐射剂量（5、10、15、20GY）分别对2个马铃薯品种的休眠块茎进行辐射诱变,分别测量2个马铃薯品种M2代叶片的叶绿素含量、干物质、淀粉含量以及产量等农艺性状,研究60Co-γ射线的不同辐射剂量对马铃薯M2代群体的诱变效应。[结果]不同辐射剂量对同一马铃薯品种M2代主要农艺性状产生的变异程度不同;相同辐射剂量对不同马铃薯品种M2代主要农艺性状所产生的变异程度不同。60Co-γ射线诱变改良个别性状（早熟、抗病性、高产、叶绿素含量）较有效,60Co-γ射线诱变马铃薯的适宜照射剂量为10～20GY,从2个马铃薯品种M2代中共单选出41个优株系。[结论]对马铃薯进行辐射诱变是一种有效的育种手段,但大多数突变是隐性突变,辐射诱变育种难度较大。     

The dynamics of bacterial community in a polyculture aquaculture system of Penaeus chinensis,Rhopilema esculenta and Sinonovacula constricta

Polyculture with Chinese shrimp Penaeus chinensis, jellyfish Rhopilema esculenta and razor clam Sinonovacula constricta (S.J.R) is a common aquaculture system in Dandong, China. Investigation on the composition and function of microbial communities and their relationship with environmental factors in aquaculture systems have crucial implications. Therefore, the sequencing of 16S rRNA gene was applied to profile the bacterial community composition of water and sediment in S.J.R polyculture system in the present study. Proteobacteria was the dominant phylum in S.J.R polyculture ponds following with Actinobacteria and Bacteroidetes in water; in contrast, more diverse phyla were detected in sediments. Water temperature, pH and dissolved oxygen were determined the bacterial community composition in the S.J.R polyculture systems. Specially, Planktomarina, PS1 clade, Candidatus Aquiluna and Fibrobacteres, which can resist the phytoplankton blooms or degrade the cellulose, were more abundant in water at the early stage of cultivation in the S.J.R polyculture system. Moreover, the functions of bacterial communities in water were mainly associated with cell communication mediated, while the functions related to basal metabolism were enriched in sediments. The findings of this study allowed us to better understand the bacterial community in the S.J.R polyculture system and accumulated data for the improvement of cultural management.     

基于仿人智能控制的长输管道新型退磁仪的智能化实现

对于年金的时间价值的研究,往往假定利率在整个期间内是固定不变的.但事实上,由于受到多种因素的影响,利率通常具有不确定性.因此,本文采用可逆MA(1)模型对随机利息力进行建模,在此基础上,研究了期末付虹式年金和期末付平顶虹式年金的时间价值问题,给出了上述两种形式年金现值的期望和方差的递推公式.通过数值仿真分析了相关参数对期末付虹式年金现值的期望值的影响,其结论对投资者的投资决策提供了参考依据.     

一个水稻三倍体×二倍体杂交F2群体的微卫星杂合性丧失

DB102为一田间发现的三倍体水稻,利用它做母本与二倍体水稻中作59杂交,得到一个早世代(F2)稳定群体,通过微卫星分析发现,该群体中有一些微卫星位点发生了杂合性丧失,且至少6条染色体上发生微卫星位点杂合性丧失(loss of heterzygoisity LOH)可能有DNA序列变化。而微卫星位点的杂合性丧失又可能与该杂交组合早世代稳定有关。     

Calculation of Maintenance Cost Based on the Proportional Life Setback Model

Maintenance cost is one of the most difficult parts to calculate in variant-cost, for it s decided by the reliability of components. As an important factor of reliability, life is largely affected by maintenance. The proportional life prolonged model based on maintenance is presented firsdy. Based on this model, the function of Mainenance--Life--Cost is deduced. Which provides a new method for power plant to calculate maintenance cost more accurately.     

A Dynamic Model for Generation Expansion Planning and Algorithm

This paper discusses the problem of long-range generation expansion planning. A dynamic model for long-range expansion planning is set up and an algorithm-a two-step programming is presented, which is used here in a case.     

A Study on the Practical Algorithm for One Dimensional Equal Stock Cutting Problem

Based on alalysing the mathematical models for one dimensional equal stock cutting problem,a knapsack column generation algorithm has been constructed,which is a successive approximate algorithm for the practical engineering.In the end of this paper,some computational examples have been presented,which show that the convergence and optimum results of the algorithm are quite good.     

基于LS-SVM的小水电站年发电量智能预测模型

针对小水电站年发电量序列的特点,将最小二乘支持向量机(least squares support vector machine,LS-SVM)回归模型引入年发电量预测领域,并给出了相应的过程和算法。与常规基于人工神经网络(artificial neural net-works,ANN)的智能预测方法比较,该模型优点是明显的:①将神经网络迭代学习问题转化为直接求解多元线性方程;②整个训练过程中有且仅有一个全局极值点,确定了预测的稳定性。最后,一个实际的预测例子表明:该模型实现容易、预测准确,适用于小水电站预测。     

带分流叶片的离心泵叶轮三维贴体网格生成

采用泊松方程进行带分流叶片的离心泵叶轮内三维贴体网格的自动生成 ,并通过源项控制来满足网格的正交性及调整网格疏密。计算时根据边界处网格线正交的控制角和控制距离的几何约束确定边界条件 ,利用分块粘接技术生成了带分流叶片离心泵叶轮内的三维分块结构化贴体网格 ,从而提高了流场流动分析中前处理环节的效率和精度 ,能使在湍流计算中广泛应用的壁面函数法的条件容易满足 ,并能使普遍采用的压力第二边界条件直接用于计算中 ,还能满足差分要求 ,减小离散误差。