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排序方式： 共有315条查询结果，搜索用时 15 毫秒
91.
省级公共图书馆公共决策服务现状调查分析 总被引：1，自引：0，他引：1
本文在对公共决策的概念和类型进行概括介绍的基础上，对我国省级图书馆公共决策服务的服务对象、服务方式、服务产品进行调查，在此基础上分析我国省级公共图书馆公共决策服务中存在的问题，并提出相应的解决措施。 相似文献
92.
对2000年欧锦赛失球情况的研究 总被引：7，自引：0，他引：7
运用灰色关联分析法对 2 0 0 0年欧锦赛失球因素、失球区域和射门方式等进行了分析研究。结果表明盯人不紧、未封住射门路线是失球的主要因素。罚球区是失球的主要区域。 相似文献
93.
以三维模型为代表的产品数据是产品档案的重要组成部分,应进行长期归档保存。本文对空客德国公司开展产品数据归档的依据、标准、系统和流程进行了详尽的介绍,通过空客德国公司的最佳实践,阐述了其对我国工业企业开展产品数据归档的启示,以期推动我国产品数据的归档工作。 相似文献
94.
研究目的:以中试规模的缺氧/厌氧/好氧/后缺氧污水处理工艺为研究对象,利用BioWin软件平台及其内嵌的通用活性污泥数学模型,建立该工艺的模拟模型并进行校正及验证,为优化该工艺的设计及运行提供指导。创新要点:成功建立了缺氧/厌氧/好氧/后缺氧工艺的活性污泥数学模型,甄别出对模型输出有显著影响的灵敏性参数。研究方法:通过呼吸试验获取进水水质特征,利用BioWinTM软件平台及其内嵌的通用活性污泥数学模型,建立该工艺的模拟模型,利用模型缺省值进行初步稳态模拟,借助灵敏度分析方法筛选出重要的化学计量学参数及动力学参数并进行模型校正,利用校正后的模型对该工艺进行了动态模拟。重要结论:灵敏度分析可优化模型的校正过程,该工艺出水水质对异养菌(OHOs)和氨氧化菌(AOB)(YH、μmaxH、Ks、bH、μmaxA、KNH4A和baeroa,A)的灵敏度较高。校正后的模型稳态模拟出水水质(pH、COD、TN、NH4+-N、NO2--N、NO3--N和TP)控制在与实测出水相应的95%置信区间内(图5),表明稳态模型建模成功,在此基础上运行的动态模拟准确地反映了工艺实际运行中的浓度变化趋势(图6),具有良好的模拟效果。 相似文献
95.
如何提高热门图书的流通速度、缓解供需矛盾是国内外图书馆研究的热点并提出了诸多解决方案,其中调整图书的借阅期限是最常用的解决方案,通过对现有的多种图书借阅期限调整方法及其优缺点进行归纳分析,在图书弹性借期制的基础上,提出了一种新的图书借期调整方法,建立了基于预约申请量的图书借期动态调整模型,以期能够满足读者的借阅需求,改善借阅体验。 相似文献
96.
97.
This paper presents neural networks based on command filtering control method for a table-mount experimental helicopter which has three rotational degrees-of-freedom. First, the controller is designed based on backstepping technique, and further command filtering technique is used to solve the derivative of the virtual control, thereby avoiding the effects of signal noise. Secondly, the model uncertainty of the table-mount experimental helicopter’s system is estimated by using neural networks. And then, Lyapunov stabilization analysis proves the stability of the table-mount experimental helicopter closed-loop attitude tracking system. Finally, the experiment is carried out to clarify the effectiveness of the proposed method. 相似文献
98.
环境战略能否驱动环境绩效和经济绩效的双赢直接关系到企业开展环境战略的积极性。为此,本文利用中国四大重污染行业2014—2018年的面板数据,实证检验了环境战略与环境绩效和经济绩效的关系。研究得出：①整体而言,企业实施环境战略能够显著实现环境绩效和经济绩效双赢。②进一步分组研究显示,不同成长阶段、不同市场竞争条件的企业环境战略不同,对其两绩效的调节效应也会存在差异,高成长性企业的环境战略显著正向影响环境绩效但并未带来显著的经济绩效,而低成长性企业的环境战略对环境绩效的影响不显著却能带来明显的经济绩效;市场竞争越激烈,环境战略对环境绩效和经济绩效的促进作用越明显,而弱竞争环境下的环境战略则作用效果比较有限。③从环境战略的实施内容看,企业只有重视长期的环境管理、绿色技术创新和绿色文化建设,而非满足于短期排污达标或规避环境违法,才能实现环境绩效和经济绩效的双赢。④新环保法实施后,企业环境战略对环境绩效的提升作用更加突出,但对经济绩效的影响不升反降。 相似文献
99.
In this study, a total sliding-mode-based particle swarm optimization control (TSPSOC) scheme is designed for the periodic motion control of an indirect field-oriented linear induction motor (LIM) drive. First, an indirect field-oriented mechanism for a LIM drive is introduced to preserve the decoupling control characteristic. Then, the concept of total sliding-mode control (TSC) is incorporated into particle swarm optimization (PSO) to form an on-line TSPSOC framework for preserving the robust control characteristics and reducing the chattering control phenomena of TSC. Moreover, an adaptive inertial weight is devised to accelerate the searching speed effectively. In this control scheme, a PSO control system is utilized to be the major controller, and the stability can be indirectly ensured by the concept of TSC without strict constraint and detailed system knowledge. With the proposed TSPSOC system, the mover position of the controlled LIM drive possesses the advantages of favorable robust characteristic, control effort without chattering, and simple control framework. Numerical simulations and experimental results are given to verify the effectiveness of the proposed control scheme for the tracking of periodic reference trajectories. In addition, the superiority of the proposed TSPSOC scheme is indicated in comparison with the TSC, Petri fuzzy-neural-network control (PFNNC) and traditional fuzzy-neural-network control (TFNNC) systems. 相似文献
100.
Quantifying the motility of micro-organisms is beneficial in understanding their biomechanical properties. This paper presents a simple image-based algorithm to derive the kinetic power and propulsive force of the nematode Caenorhabditis elegans. To avoid unnecessary disturbance, each worm was confined in an aqueous droplet of 0.5 μl. The droplet was sandwiched between two glass slides and sealed with mineral oil to prevent evaporation. For motion visualization, 3-μm fluorescent particles were dispersed in the droplet. Since the droplet formed an isolated environment, the fluid drag and energy loss due to wall frictions were associated with the worm''s kinetic power and propulsion. A microparticle image velocimetry system was used to acquire consecutive particle images for fluid analysis. The short-time interval (Δt < 20 ms) between images enabled quasi real-time measurements. A numerical simulation of the flow in a straight channel showed that the relative error of this algorithm was significantly mitigated as the image was divided into small interrogation windows. The time-averaged power and propulsive force of a N2 adult worm over three swimming cycles were estimated to be 5.2 ± 3.1 pW and 1.0 ± 0.8 nN, respectively. In addition, a mutant, KG532 [kin-2(ce179) X], and a wild-type (N2) worm in a viscous medium were investigated. Both cases showed an increase in the kinetic power as compared with the N2 worm in the nematode growth medium due to the hyperactive nature of the kin-2 mutant and the high viscosity medium used. Overall, the technique deals with less sophisticated calculations and is automation possible. 相似文献