363 research outputs found

    The Relations Among Leadership and Team Performance

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    文章通过团队凝聚力来查验领导行为对团队绩效的间接作用,特别是,通过实证分析来检验如下几个关系:团队中的领导与团队绩效之间的关系、团队凝聚力与团队绩效之间的关系、领导与团队凝聚力的关系。结果表明:领导行为与团队绩效之间的关系并不显著,其中,领导者关系型行为与团队绩效弱相关,而领导者任务型行为与团队绩效不相关。领导行为与团队凝聚力之间存在显著正相关,This research verified the indirect effect of leadership on team performance,especially these relations:the relationship between leadership and team performance,the relationship between team cohesion and team performance,the relationship between leadership and team cohesion.The results were these: the relation between leadership and team performance was not significant;leadership was significant positive to team cohesion,team cohesion is significant positive to team performance.教育部人文社会科学一般项目(08JC630069);湖南文理学院科研基金重点项目(JJZD0907

    Parametric optimum design of an irreversible photon-enhanced thermionic emission solar cell hybrid system

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    考虑实际系统中存在的多种传热损失,本文建立一类不可逆光子增强热离子发射太阳能电池与温差热电发电器组合而成的混发电系统模型.基于太阳能电池与温差热电发电器之间的能量平衡方程,导出该混合系统输出功率和效率的表达式.通过数值计算,详细分析了光增热离子太阳能电池的面积、阴极半导体材料的禁带宽度、电子亲和势以及温差热电发电器的无量纲电流对混合系统优化性能的影响,确定混合发电系统运行于最大效率下光子增强热离子太阳能电池阴极材料的禁带宽度,电子亲和势,电池面积和温差热电发电器的无量纲电流的优化值.结果表明,采用混合发电系统,太阳能转换效率与工作于相同条件下的单一光增热离子太阳能电池的效率相比可提高约10%,而光增热离子太阳能电池阴极半导体材料禁带宽度在最大效率下的优化值则比单一光增热离子太阳能电池的小.本文所得结果可为实际光子增强热离子太阳能电池混合发电系统的设计和优化运行提供理论依据.A class of an irreversible thermodynamic model of the hybrid power system consisting of a photon-enhanced thermiomic emission solar cell(PETSC) and a thermoelectric generator(TEG) is established, in which some main irreversible losses existing real hybrid systems are taken into account. Based on equations of the energy balance between the solar cell and thermoelectric generator,expressions for the power output and efficiency of the hybrid system are derived. By using the numerical calculation, influences of the cell area, the energy band gap and electron affinity of the cathode semiconductor materials, and the dimensionless current of the generator on the optimal performance of the hybrid system are analyzed in detail. Under the operating condition of maximum efficiency, the optimal values of some important performance parameters of the hybrid system, such as the energy band gap, electron affinity, area and dimensionless current, are given. The results obtained in this paper show that by using the hybrid system, the solar energy conversion efficiency can be increased by about 10% and the optimal value of the energy band gap for the PESTC of the hybrid system at maximum efficiency is smaller than that of the energy band gap for alone operating PESTC. All the results obtained in this article will provide some theoretical basis for the design and optimal operation of practical PETSC hybrid system.国家自然科学基金(批准号:11175148,11305064);; 福建省自然科学基金(批准号:2011J01012);; 华侨大学引进人才科研启动资金(编号:09BS510)资助项

    国外设计院校教育对中国设计艺术院系发展的启示

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    笔者在考察分析国外多所设计院校教育特色的基础上,针对当前中国艺术院系的办学模式及现存问题,提出了构建有中国特色艺术设计院校产学研合作模式的几种设想和艺术设计院校合作发展模式实施方法的五项建议

    Barnacle damage and its control in young mangrove plantations: A research review.

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    随着近年来红树林恢复性造林面积的扩大,海洋污损生物藤壶对红树林幼林的危害问题日益突出.文中综述了藤壶附着的生物化学、藤壶在红树林附着的生态学、藤壶对人工红树林幼林的危害和国内所采用的化学药物防治措施等方面的研究进展,以及今后的研究方向.藤壶在红树林的附着和分布模式受海水盐度、浸淹深度、林分郁闭度、水文条件等环境因素和生物因素的影响.而藤壶胶粘蛋白的氨基酸组成、一维结构,胶粘蛋白在水下的交联、组装和胶粘的过程与机制,以及藤壶危害红树幼苗的机制和危害权重尚需要深入探讨.研究红树植物对藤壶附着的响应和长期适应机制将为藤壶的防治提供更多的启示. 【英文摘要】 With the increasing area of restored mangrove vegetation, marine-fouling organisms, barnacle in particular, are suggested to be an important factor affecting the survival and growth of mangrove seedlings. This paper reviewed the biochemical and ecological studies on the settlement of barnacle, its damage on mangrove seedlings, and its chemical control. The settlement and distribution model of barnacle on mangroves is significantly affected by the environmental factors such as seawater salinity, tide inundat...国家自然科学基金项目(30270272);; 厦门市海洋与渔业局、翔安农林水利局资助项目(2005-2008)

    Understand on concept of estuary ecosystem safety

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    主要阐述生态安全的概念,对生态安全概念的起源、发展及国内外学者对生态安全概念的理解进行归纳总结。生态安全的概念应该包括生态健康、生态服务、生态风险三部分内容。本文在对生态安全概念研究的基础上,归纳分析河口生态安全的内涵。河口生态安全概念的认知和理解是河口生态评价和管理的基础,本文将以此为目的积极进行生态安全及河口生态安全概念的探索、分析和归纳总结。The concept of ecosystem safety is studied in this paper.Its origin and development as well as the domestic and foreign scholars on it are summarized.The concept of ecosystem safety includes the ecosystem health,service as well as risk.The summary and analysis of the estuary ecosystem safety connotation are made based on the studies of the ecosystem safety concept.The learning and understanding of the estuary ecosystem safety concept is the first step to valuate and manage the estuary ecosystem.For this purpose,the analysis and summary of the estuary ecosystem safety concept were given.海洋公益性行业科研专项(200805064);国家908专项(908-02-03-01

    Biomass and growth analysis of Paspalum wettsteinii community in South Fujian, China

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    禾本科多年生牧草宽叶雀稗适宜在福建南亚热带丘陵酸性赤红壤上生长,人工种植的宽叶雀稗群落鲜草产量峰值在8月份,为4050g·m-2,生物量峰值(干重)则出现在9月份,其中地上部1398.8 g·m-2、地下部770.8g·m-2。群落全年生长呈周期性变化,生物量波动符合Logistic曲线:y=1634.46/(1+e2.67976-1.3.369×10-2t)。根据9月份最高现存量估计,其年净第一性生产力为2169.6g·m-2·a-1。群落生长分4个阶段:缓慢增长(2~4月)、加速增长(5~6月)、减速增长(7~9月)、生长停滞和下降(10~12月)。降雨量是影响生物量的重要因素,二者呈显著线性正相关,相关系数为0.9783,回归方程为y=-74.3779+0.9480x。Paspalum wettsteinii Hackel, a kind of perennial herbages of Graminaea, was proved to get good adaptation to hilly crimson soil in the southern part of subtropical zone in Fujian Province. Its growth curve fluctuated periodically within a year. The biomass value of above-ground part of the community reached to its highest point, 1398. 8 g m-2 in August, 1994; the under-ground part 770. 8 g m-2 in September. Biomass of the community fluctuated in accordance with the logistic curve: y=1634. 46/ (1+e2.67976-1.30369x10-2t) . The highest value of the community's fresh weights measured monthly was 4050 g m-2 (Aug. 1994) . Estimated by Peak Standing Crop in Sept. 1994, the annual NPP of the community was 2169. 6 g m-2 a-1. Through a growth analysis, the above ground part biomass of the community changes with four stages: slow increasing (Feb. -Apr. ); acceleration increasing (May-June); deceleration increasing (July-Sept. ); stagnation and descent (Oct. - Dec. ). Of all the factors that affect the biomass value, the rainfall was an important one. Their regression equation was y= - 74. 3779+0. 9480x, and the relation coefficient (r) was 0. 9783

    Giant Raman Enhancement on nanoporous Gold Film By Conjugating with nanoparticles for Single-molecule Detection

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    Hot spots have the contradictively geometrical requirements for both the narrowest interstices to provide strong near-field coupling, and sufficient space to allow entrance of the analytes. Herein, a two-step method is employed to create hot spots within hybrid nanostructures, which consist of self-supported nanoporous gold films with the absorbed probes and subsequent nanoparticle conjugates without surface agents or mechanical motion. The molecules confined into 1 nm interstice exhibit 2.9 × 107 times enhancement in Raman scattering compared to pure nanoporous gold. Giant enhancement primarily results from strong near-field coupling between nanopore and nanoparticle, which is theoretically confirmed by finite-difference time-domain simulation. Excellent detection limits toward 10−11 mol l−1 offer an opportunity to track spatial orientation of single molecule and engineer hybrid nanostructures as commercial SERS substrates

    Study on the characteristics of Syzygium cumini L. pigment

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    以海南蒲桃成熟果实为原料提取天然色素,并对其理化性质进行了分析研究。同时比较了D-072、D-401、D-301-G、D-101、D-110、DF01六种树脂对该色素的静态吸附情况及不同极性解吸剂对吸附色素的树脂洗脱的效果,从中选择吸附和解吸附效果最好的树脂以及适合的解吸剂。研究表明:该色素在酸性条件下对热、金属离子和常用食品添加剂均具有较好的稳定性,对光稳定性稍差;D-072大孔吸附树脂对海南蒲桃色素吸附效果最好,色素吸附率达90.7%;解吸剂用含0.2%三氟乙酸的50%酸化乙醇,色素可被充分洗脱下来。此研究结果为以海南蒲桃成熟果实为原料来生产食用色素提供了理论依据。The stability of pigment which was extracted from the fruit of Syzygium cumini was studied. In addition, absorbing and separating Syzygium cumini pingment with macroreticular resin was also studied. Static absorption capacity of six resins(D-072, D-401, D-301-G, D-101, D-110, DF01) for the pigment was compared. From these resins, the one with the best absorpting and desorpting effect was elected. The results showed that this kind of pigment has a better stability toward heat, metal ion and common food additives under acidic condition, and it is more tolerable of heat than light. The adsorption ability of D-072 resin was the best and the adsorptive rate of pigment reached 90.7%. When 50% ethanol contained 0.2% TFA was used as desorptive solvent, the pigment could be sufficiently desorpted and the effect of desorption would be better. It has a great prospect in the exploration and application in food industry to produce the food pigment from the fruit of Syzygium cumini.国家自然科学基金项目(30671646

    The evaluating index system for estuary ecosystem safety based on PSR model

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    PSr模型是有效的生态评价和管理模型,近年来其在生态系统评价领域的运用越来越普遍。本文对PSr模型的产生、原理及其主要的类型进行介绍,介绍其在生态评价领域的运用概况,并重点介绍其在流域-河口及海洋生态安全评价中的运用,为河口生态安全评价做准备。本文对PSr模型在河口生态安全评价中的适用性进行分析,并基于PSr模型构建了河口生态安全评价指标体系,最后指出该模型在评价中存在的主要问题。PSR model is an efficient model for evaluating and managing ecosystem and has been used more and more popular in the field of ecosystem assessment in recent years.This paper introduced the origin,theories and types of PSR model,as well as its application in the field of ecosystem assessment,especially the assessment of base-estuary and ocean ecosystem safety,searched for assessing the estuary ecosystem safety.Practicability of PSR model in the assessment of estuary ecosystem safety was analyzed.It constructed the index system of estuary ecosystem safety assessment and put forward some problems about this model eventually.海洋公益性行业科研专项(200805064);国家908专项(908-02-03-01

    电学开路挠曲电悬臂梁自振频率分析

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    挠曲电效应是一种新兴的机电耦合效应,在微纳米尺度的传感器、致动器和俘能器方面有广阔的应用前景.本文基于挠曲电材料的变分原理和电吉布斯自由能,推导了表面覆盖电极的挠曲电悬臂梁在电学开路条件下的机电耦合动力学控制方程和相应的力电边界条件.进一步获得了求解电学开路条件下挠曲电悬臂梁自振频率的超越方程.以聚偏氟乙烯(PVDF)材料为算例,讨论了挠曲电系数、末端质量块和梁尺寸对结构自振频率和电学开路/短路条件下结构自振频率有效频移的影响.计算结果表明,挠曲电系数的增大会提高梁的自振频率;末端质量的增大可以降低梁的自振频率,并且末端质量块的转动效应对悬臂梁自振频率的影响很小;悬臂梁结构的有效频移随着结构尺寸减小而增加,并在某一厚度尺寸趋于饱和值.国家自然科学基金(11572271
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