共查询到19条相似文献，搜索用时 265 毫秒
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信息高速公路与图书馆发展趋势 总被引：2，自引：0，他引：2
本文从信息高速公路的产生及所带来的全球效应入手，阐述了信息高速公路建成后．新世纪的图书馆发展趋势．并提出了图书馆适应信息高速公路的策略。 相似文献
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本文通过考察信息运动模型和信息约束．建立信息作用模型，揭示信息作用必须遵从物理层次和信息层次的5个匹配规则．提出信息作用机理，并应用作用机理从人类信息活动和组织系统两方面考察信息作用效应，提出信息增益效率理论。 相似文献
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牛鞭效应是供应链管理中普遍存在的现象，牛鞭效应的存在使得供应链中冗余库存积压，成员企业生产计划盲目扩大，给企业带来了严重的负面影响。从供应链牛鞭效应的存在和影响出发，深入分析其成因，并提出了削弱牛鞭效应的相应策略。 相似文献
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跨国公司中的技术溢出效应述评 总被引：10，自引：0，他引：10
技术扩散中的溢出效应是经济外在性的一种表现，跨国公司在东道国的技术溢出效应是国际技术溢出的主要表现形式。文章通过时溢出效应理论发展的回顾及评述，总结了跨国公司在东道国发生溢出效应的主要途径和影响因素；并结合溢出效应的相关理论，为我国企业技术创新提出了相应的建议。 相似文献
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A homing mechanism is required for repositioning as a system performs tasks repeatedly. By examining the effect of poor repositioning on the tracking performance of iterative learning control, this paper develops a varying-order learning approach for the performance improvement. Through varying-order learning, the resultant system output trajectory is ensured to follow a given trajectory with a lowered error bound, in comparison with the conventional fixed-order method. A discrete-time initial rectifying action is introduced in the formed varying-order learning algorithm, and a sufficient condition for convergence is derived. An implementable scheme is presented based on the proposed approach, and illustrated by numerical results of two examples of robotic manipulators. 相似文献
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声自导技术的基础是波束形成技术,对波束形成技术的研究能够让我们更好地提高水下航行器的自动导引能力。本文首先对声自导系统的模型和基本职能进行了简单介绍,然后对波束形成技术和方位估计（参数估计）技术在无人水下航行器声自导技术上的应用进行了初步的研究,为我们将来发展新型无人水下航行器提供了一定的理论基础。 相似文献
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This paper presents a novel integrated guidance and control strategy for homing of unmanned underwater vehicles (UUVs) in 5-degree-of-freedom (DOF), where the vehicles are assumed to be underactuated at high speed and required to move towards the final docking path. During the initial homing stage, the guidance system is first designed by geometrical analysis method to generate a feasible reference trajectory. Then, in the backstepping framework, the proposed trajectory tracking controller can achieve all the tracking errors in the closed-loop system convergence to a small neighbourhood of zero. It means that the vehicle's dynamics are consistent with the reference trajectory derived in the previous step. To demonstrate the effectiveness of the proposed guidance and control strategy, the complete stability analysis used Lyapunov's method is given in the paper, and simulation results of all initial conditions are presented and discussed. 相似文献
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Valery Y. Glizer Vladimir Turetsky Leonid Fridman Josef Shinar 《Journal of The Franklin Institute》2012,349(2):638-657
In order to construct the guidance strategy in a realistic nonlinear noise-corrupted interception endgame against a maneuverable target, a linearized zero-sum differential game is considered. Assuming perfect information in this game, sufficient conditions are established, which guarantee that a continuous interception strategy with memory (history-dependent) has the maximal capture zone. Two examples of such a strategy are analyzed: a modified super-twisting second-order sliding mode control and a modified integral sliding mode control. Simulation results of the original nonlinear interception endgame demonstrate that these strategies considerably reduce the chattering created by the classical game optimal bang-bang strategy without deteriorating the homing performance. 相似文献
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针对新疆淖毛湖矿区深部构造复杂区段,应用三维地震叠前偏移技术实现了复杂构造的精确归位,提高了资料解释精度,使最终的地质成果可靠程度提高。 相似文献
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Jun Dai Meng Wu Quan Wang Siyang Ding Xiaoqi Dong Liru Xue Qingqing Zhu Jian Zhou Fan Xia Shixuan Wang Yuning Hong 《国家科学评论(英文版)》2021,8(6)
Red blood cell (RBC)-mimicking nanoparticles (NPs) offer a promising platform for drug delivery because of their prolonged circulation time, reduced immunogenicity and specific targeting ability. Herein, we report the design and preparation of RBC membrane-bound NPs (M@AP), for tumoral photodynamic-immunotherapy. The M@AP is formed by self-assembly of the positively charged aggregation-induced emission luminogen (AIEgen) (named P2-PPh3) and the negatively charged polyinosinic : polycytidylic acid (Poly(I : C)), followed by RBC membrane encapsulation. P2-PPh3 is an AIE-active conjugated polyelectrolyte with additional photosensitizing ability for photodynamic therapy (PDT), while Poly(I : C) serves as an immune-stimulant to stimulate both tumor and immune cells to activate immunity, and thus reduces tumor cell viability. When applied in tumor-bearing mice, the M@AP NPs are enriched in both the tumor region as a result of an enhanced permeability and retention (EPR) effect, and the spleen because of the homing effect of the RBC-mimicking shell. Upon light irradiation, P2-PPh3 promotes strong ROS generation in tumor cells, inducing the release of tumor antigens (TA). The anti-tumor immunity is further enhanced by the presence of Poly(I : C) in M@AP. Thus, this strategy combines the PDT properties of the AIE-active polyelectrolyte and immunotherapy properties of Poly(I : C) to achieve synergistic activation of the immune system for anti-tumor activity, providing a novel strategy for tumor treatment. 相似文献
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软土地区深基坑工程具有时间效应。基坑的各项参数,比如墙体水平位移和支撑轴力等,其数值不会因开挖的停止而不再发生变化。其原因一般地是土体固结和流变等效应所引起的。本文采用MERCHANT模型来模拟土体的流变性,依据Biot固结有限元法编制了有限元分析程序。程序分别以渗透系数和粘滞系数来反映固结的快慢和流变性的强弱。通过计算温州地区饱和软粘土地基深基坑开挖工程实例,验证了程序的可信性。程序通过对参考算例的分析,分别得到了纯固结作用和流变与固结耦合作用对基坑性状影响的规律:固结有利,流变不利,耦合作用使得具体的各项参数表现复杂化。 相似文献
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Using information on 31 in-depth cases of individual M&A deals, we show that technological and market-relatedness between M&A partners distinctly affects the inputs, outputs, performance and organisational structure of the R&D process. While the findings in the literature on the effect of M&A on R&D are quite mixed, we can sharpen results by analysing data at the level of the R&D process. This comes at the price of a smaller sample and more qualitative data, for which caution in the interpretation is necessary. M&A between partners with ex-ante complementary technologies result in more active R&D performers after the M&A. In sharp contrast, when merged entities are technologically substitutive, they significantly decrease their R&D level after the M&A. Moreover, R&D efficiency increases more prominently when merged entities are technologically complementary than when they are substitutive. These two findings on the R&D level and the performance support the scope economy effect of M&A, on the one hand, and reject the scale economy effect of M&A, on the other. Next, for cases in which partners were active in the same technological fields before the M&A, the reduction of R&D is more prominent, while the R&D efficiency gain is smaller if merged entities were rivals in the product market prior to their merger than if they were non-rival. This suggests that rival firms reap little technology gains from mergers. 相似文献
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异地并购是一种打破市场分割现象,实现资源高效配置的重要形式。针对前期文献中学者们对异地并购中地理距离和技术资源跨区域流动之间影响关系的研究存在较大差异,本文基于经济地理理论和信息不对称理论,以2009-2019年间我国高新技术上市企业发生的异地并购交易为研究样本,研究了地理距离对技术资源跨区域流动的影响效应以及并购双方技术重叠的调节作用。研究结果表明,地理距离对技术资源跨区域流动有显著的负向影响,在分组回归中,这种负向影响在制造业和新创企业分组中更显著；技术资源重叠对地理距离和技术资源跨区域流动间负向关系有显著的缓解效应。进一步研究发现,并购方董事长和总经理两职分离、独董地理临近性以及高管团队规模能显著削弱地理距离的负面影响效应。研究结论从并购前标的方选择和并购后资源整合的双视角为如何缓解异地并购中地理距离的束缚效应提供了理论依据,深化了我们对跨区域资源流动中地理距离影响效应的认知。 相似文献