224 research outputs found

    Research on the Relationship between Feedback-seeking Behavior and Performance Evaluation ——Based on the Moderating Effect of Goal Orientation

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    外部环境正在持续发生剧烈的变化,企业所面临的竞争压力不断加重,这就需要企业不断提升组织内部的竞争力。员工是企业最大的生产力,对于提升企业竞争力起到至关重要的作用。反馈寻求行为是一种能够使员工获得有效信息,正确的开展工作以及制定合适目标的行为。员工和上级管理者共同致力于发挥反馈寻求行为的作用显得非常重要,因为员工更多的是向上级管理者寻求反馈。但是上级管理者是否能识别出员工在寻求反馈,并且对于反馈寻求行为做出正确的反应呢?这个问题已经引起了学术界的注意与重视。但是,本文通过对反馈寻求行为进行文献回顾时发现:反馈寻求行为的结果变量研究较少,并且很少有文献完全站在上级管理者的角度对反馈寻求行为进行研究...The external environment is dramatically transforming overtime, meanwhile enterprises have been faced with fierce competition pressure, which requires them to constantly improve their competitiveness within organization. Employees are the most precious assets of an enterprise and always play a crucial role in enhancing its competitiveness. Feedback-seeking behavior is a kind of behavior that enabl...学位:管理学硕士院系专业:管理学院_企业管理学号:1762012115123

    塔里木沙漠公路防护林生态工程的综合生态环境效应

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    为了探讨重大工程的生态环境效应,从风沙环境、土壤环境、小气候、生物多样性和地下水环境5个方面对塔里木沙漠公路防护林工程的综合生态环境效应进行了研究.结果表明:(1)防护林改变了近地表风沙运动过程,防沙体系内风速、输沙率降低幅度分别达64%~80%和87.45%~99.02%,风沙流结构、沙物质粒度、地表蚀积状况也发生了明显变化;(2)与自然流沙地相比,防护林土壤容重减小,全盐含量、总孔隙度和含水量增大,土壤肥力质量明显提高,其变化基本呈现"先快后慢"的规律;(3)防护林对于小环境改善作用明显,距地面6m范围内,林地不同高度的空气温度普遍低于自然流沙地,而空气湿度则高于自然流沙地,林地土壤温度也低于自然流沙地;(4)随着防护林内生境的变化,土壤微生物种类显著增加,但不同种类微生物的种群分布并不均匀;(5)目前防护林灌溉抽水对地下水位、地下水矿化度的影响不大,水位在厘米级范围波动,矿化度的变化幅度在±1g·L-1左右,且没有明显的变化趋势

    An Auto Composing Method for Motive of Inventions Based on Genetic Algorithm

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    遗传算法作曲就是利用遗传算法来实现乐曲的生成,在创作的过程中遗传算法按照事先给定的规则进行进化,从而使得人在计算机创作的过程中介入程度达到最小。动机是巴赫创意曲中的核心旋律和主题,文中采用遗传算法对创意曲中动机的自动生成进行了探讨。介绍了遗传算法创作动机的基本过程,即按照动机创作的音乐知识规则来设置适应度函数,采用遗传算法中的选择、交叉和变异算子产生动机片段,最终达到生成自动生成动机片段的效果。Genetic algorithmic composition basically refers to using genetic algorithm to compose the melody.The genetic algorithm evoluted based on the rules to create music with minimal human intervention.Motive is the core and the theme of the Bach's inventions.Uses the genetic algorithm to do some research on auto composing the motive of inventions.Introduced the basic process of composing motive using genetic algorithm.Namely,setting the fitness function based on the rules of the music knowledge of the motive composing,used the selection,crossover and mutation operators to produce the motive segment.Finally,the motive segment can be auto composed

    电激励下基于挠曲电效应的外毛细胞力电耦合分析

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    耳蜗内的外毛细胞在电激励下的力电耦合运动是耳蜗放大主动机制的重要基础.以耳蜗外毛细胞为研究对象,基于外毛细胞侧壁的特殊膜结构,推导膜曲率变化、轴向伸缩与跨膜电位差之间的相互关系,建立外毛细胞挠曲电-压电线性等效模型,进而获得整体的等效压电系数.建立外加电激励下细胞轴向振动的动力学控制方程和动态电学方程,并结合相应的力学和电学边界条件进行分析,从频域上讨论细胞材料参数和流体阻力对外毛细胞电动性机制的影响.计算结果表明:在高频区域随着激励频率的增加,流体阻力限制机械功的输出;机械功输出大小和峰值所对应的激励频率与细胞长度、外膜挠曲电系数和细胞基部电阻抗有关,当细胞越长、挠曲电系数或细胞基部电阻抗越大时,机械功输出越大,其对应峰值的激励频率越小

    中国邻近边缘海碳通量研究现状与展望

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    集成分析了南海、东黄渤海等中国邻近边缘海(简称中国边缘海)海-气界面CO2通量及其所表征的CO2源汇格局,简析海-气CO2通量的主要控制因素;总结了河-海界面、边缘海与大洋的交换界面及输出真光层的碳通量,进而初步构架了简化的中国边缘海碳收支;并与世界其他陆架边缘海碳的源汇格局和通量作了比对,最后对边缘海碳循环研究进行了展望.从周年尺度上看,中国边缘海是大气CO2的源,全年向大气的释放量为(9.5±53)Tg C;河流经过河口输送至中国边缘海的总碳量为(59.6±6.4)Tg Ca-1;中国境内河口释放CO2的总量为(0.74±0.02)Tg Ca-1;西太平洋每年输入中国边缘海的总碳量为2.5Pg Ca-1,可见,西北太平洋输入中国边缘海的碳通量巨大.中国边缘海上层海洋颗粒有机碳输出通量为(240±80)Tg Ca-1.国家自然科学基金项目(批准号:91328202、91428308);;科技部重大科学研究计划项目(编号:2015CB954001);;国家海洋局海洋公益项目(编号:201505003-3);;全球变化专项项目(编号:GASI-03-01-02-02)资

    端部质量块对悬臂梁型挠曲电俘能器性能的影响

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    端部质量块对悬臂梁型挠曲电俘能器的性能具有显著的影响.以电吉布斯自由能为基础,基于Euler-Bernoulli梁模型,利用挠曲电材料的变分方法,推导带端部质量块的挠曲电俘能器结构的机电耦合动力学控制方程和相应的力电边界条件;利用分离变量法推导结构在短路条件下的振型正交条件和归一化振型参数;结合模态叠加法推导出挠曲电俘能器在外加简谐激励条件下位移和电势响应的解析形式.数值分析结果表明,端部质量块质量的增加和尺寸的减小可以提高俘能器输出功率并降低其共振频率,并且具有调节挠曲电俘能器最优外加电阻负载的功能.此外,当端部质量块尺寸一定时,端部质量块的质量越大,采用质点模型分析所带来的误差越明显.国家自然科学基金(11572271

    Studies on the Interactions between Bioactive Peroxovanadium Complexes Bearing Organic Ligands and Histidine

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    在合成和表征了 4种具有较强生物活性双过氧钒配合物K3 [VO(O2 ) 2 (ox) ]·2H2 O ,Na[VO(O2 ) 2 (bipy) ]·5H2 O ,K[VO(O2 ) 2 (phen) ]·3H2 O和K2 [VO(O2 ) 2 (pic) ]·2H2 O [分别缩写为pV(ox) ,pV(bipy) ,pV(phen)和pV(pic) ,其中ox为草酸根 ,bipy为 2 ,2′ 联吡啶 ,phen为邻菲咯啉 ,pic为 2 羧酸吡啶负离子 ]的基础上 ,利用多种NMR技术和电喷雾质谱 (ESI MS)研究了这 4种含有机配体双过氧钒配合物与组氨酸 (His)在溶液中的相互作用以及反应物浓度、时间、pH等对相互作用体系的影响 .51VNMR跟踪监测的结果表明 :双过氧钒配合物pV(ox)和pV(pic)与His在中性水溶液中存在强配位相互作用 ,而pV(bipy)和pV(phen)与His在中性水溶液中无明显作用 .我们还利用谱学方法确定了pV(ox)和His相互作用后所生成产物是pV(ox)分别与His咪唑基上的 3 N和 1 N配位的一对异构体.  In order to explore the structure2activity relationship and molecular mechanism of the specific recognition between peroxovanadium (pV) complexes bearing organic ligands and the target enzymes of tyrosine phosphatase , several NMR techniques and ESI2MS were used to study the interactions of four pV complexes {pV(ox) , pV ( bipy) , pV (phen) and pV (pic) , where pV = [VO (O2 ) 2L ] n - , in which L = oxalic acid dianion (ox) , bipyridine (bipy) , 1 ,102phenanthroline (phen) , and pyridine222carboxylic acid (pic) } towards histidine. Strong coordination interactions between imidazole of histidine and vanadium of pV(ox) or pV(pic) were observed in neutral solution , while there are not obvious interactions between histidine and pV(bipy) or pV(phen) . All 13C and 1H NMR signals of 1∶1 stoichiometric mixture of pV(ox) and histidine were assigned. Spectroscopic studies demonstrated that new complexes in the mixture of pV(ox) and histidine are a pair of isomers in which the vanadium in pV(ox) binding to the 32N and 12N of the imidazole ring. Moreover , the results of effective factors on the interaction system indicated that the new isomers were stable under the condition of physiological pH and the structure2activity relationship of these pV complexes may be relevant to their specific recognition towards histidine residues in tyrosine phosphatase.国家自然科学基金 (Nos.2 0 172 0 42 ,2 9832 0 2 0 )资助项

    Study of Underwater Target Recognition for Torpedo Electromagnetic Fuse with High Detecting Precision

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    鱼雷武器系统的主动电磁引信回波信号中蕴含着雷目交会过程重要特征信息。针对回波信号能量比较法受到直达场耦合成分和噪声影响的问题,提出了基于数字信号处理技术的目标特征提取算法。对接收天线的回波信号进行全相位二次补偿处理;采用短时傅里叶变换对目标回波信号进行包络解调;再利用改进的三次多项式最小二乘拟合方法,以抑制数据波动影响并提高计算效率;提出一种基于钟型脉冲的参数识别算法对回波包络极大值点进行估计。仿真和试验数据验证表明所提出方法具有一定的工程实用性。Characteristic information is hidden in the received signal of active torpedo electromagnetic fuse.The conventional burst controlling strategies based on energy-comparison are affected by ambient and electromechanical noises.The improved algorithms based on digital signal processing techniques are proposed.The received signals are first processed by all-phase compensation method to eliminate the direct coupling component,and then the residual signal is demodulated using STFT.An improved polynomial least mean square approximation method,which reduces the computation time,is presented for eliminating the side-effects brought by noise.A parametric estimation model base on bell-shape impulse is used to estimate the maximum of echo envelope.Simulation and trial data show that the proposed algorithm is effective and practical.国家自然科学基金项目(51275384、51275382); 国家科技重大专项(2010ZX04014-016

    A DDA Calculation on the Optical Properties of Silver Nanorods

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    【中文文摘】利用离散偶极近似 (Discretedipoleapproximation ,简称DDA)的方法 ,从理论上对粒子的形状、尺寸及周围介质等因素对银纳米粒子 ,特别是银纳米棒的光学性质的影响进行了较系统的研究 .计算表明 ,置于空气中的棒状银纳米粒子的光学性质与其形状密切相关 ,纵向表面等离子体共振吸收峰的位置随纳米棒长径比的增加呈现线性红移关系 .给出了空气中银纳米棒纵向表面等离子体共振吸收峰的位置随长径比变化的DDA拟合公式 .如果将金属纳米粒子置于折射率更高的介电环境中 ,其纵向等离子体共振吸收峰的位置进一步呈现线性红移关系 .合成的银纳米粒子的TEM图像及相关的UV VIS消光光谱显示DDA计算结果与实验值相当一致 .DDA算法与Mie′s理论在计算球状银纳米粒子的消光系数时给出很接近的结果 ,这表明用DDA的方法来分析银的光学性质是准确可靠的 ;而DDA算法对银纳米棒消光特性的成功拟合则表明 ,该算法相对Gans′理论而言 ,在研究纳米粒子的光学性质时具有更广的适用性及更高的准确性 . 【英文文摘】The optical properties of metal nanoparticles are quite different from those of the bulk materials mainly due to the collective oscillations of their conduction electrons known as the surface plasmon resonance (SPR), which is strongly dependent on the particle shape and size, and the dielectric properties of the local environment where the nanoparticles are embedded in. Based on the discrete dipole approximation (DDA) method, we studied the optical properties of silver nanorods with different aspect ratios ...Project supported by the National Natural Science Foundation of China (2 0 2 2 80 2 0,2 0 0 2 10 0 2
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