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71.
教学管理信息系统的建立可以确保学校教学数据的一致性,实现数据信息资源的分级共享,替代原始的纸张流转。通过计算机和网络系统得以规范教务管理流程、学生管理流程。本文结合目前高等院校教学特点,介绍如何利用对象关系映射技术(ORM)构建B/S三层模式的教学管理信息系统。  相似文献   
72.
This article describes a finite difference scheme which is linearly uncoupled in computation for a nonlinearly coupled Schrödinger system. This numerical scheme is proved to preserve the original conservative properties. Using the discrete energy analysis method, we also prove that the scheme is unconditionally stable and second-order convergent in discrete L2L2-norm based on some preliminary estimations. The results show that the new scheme is efficiency.  相似文献   
73.
声学参量换能器阵及其测试系统设计   总被引:1,自引:0,他引:1  
根据声学参量阵原理,设计了一个3×3的九元矩形换能器阵及其测试系统,并在空气进行验证性实验;系统包括正弦信号产生电路、信号控制电路、功率放大电路以及回波信号接收电路等,辅以LabVIEW平台,实现正弦信号和脉冲控制信号的产生,发射信号时间长度控制以及功率放大,并最终驱动换能器阵;实验表明,当有85kHz和90kHz的正弦信号产生时,系统各部分均能正常工作,能够听到天花板处有声响,且回波信号中含有5kHz的频率成分,即证明换能器阵及其系统的设计均是可行的.  相似文献   
74.
遗传编程在符号回归中的应用   总被引:1,自引:0,他引:1  
遗传编程是一种新型的搜索优化技术,文章介绍了遗传编程的基本原理,以及遗传编程的算法设计及其实现的几个关键问题,并研究了基于遗传编程方法的符号回归。与传统回归方法相比,该方法得到的拟合函数更精确,具有更广泛的适用性。文中通过对一个函数进行符号回归验证,说明此方法合理可行。  相似文献   
75.
介绍了数字化校园的建设原则、目标、以及学院分阶段实施数字化校园建设的规划.  相似文献   
76.
This paper solves the problem of adaptive fault-tolerant control of uncertain switched nonlinear systems with unknown parameters and actuator failures. Based on the multi-Lyapunov function method, a novel adaptive switched controller with tuning function is designed using the backstepping procedure. Meanwhile, a switched fault-tolerant adaptation mechanism is also given to compensate the fault efficiency. Furthermore, it is certificated that all the signals of the closed-loop system are uniformly bounded and the tracking error restrain to a small neighbor. Finally, the simulation results verify the feasibility of the proposed method.  相似文献   
77.
Metal micropatterns play critical roles in flexible electronics. However, the lack of versatile strategies for micropatterning of diverse metal materials on various thin, flexible or stretchable substrates has limited the rapid development of flexible electronics. Here, a metal micropatterning method by triboelectric spark discharge under atmospheric environment is developed, where a triboelectric nanogenerator (TENG) is employed to precisely and safely control the voltage, current, and frequency of the spark discharges. Micropatterns of metal films like gold, silver, copper, aluminum and platinum are successfully fabricated on substrates of polyimide, polyethylene terephthalate, polyvinyl chloride, polydimethylsiloxane, paper or latex, even on ultrathin substrates (5 μm thick) without damage, where the feature sizes of metal patterns are controllable from 20 μm to 1 mm. Experimental insights into the triboelectric spark discharge behaviors and the pattern feature sizes control are discussed. A straightforward fabrication of metal patterns on the balloon surface or human skin through “handwriting” by a pencil as discharge electrode is realized. Besides metals, extended processibility of conductive materials like carbon nanotubes, graphene, MXene, graphite, carbon fibers, and conductive polymers are also demonstrated. This work proves the possibility of microfabrication by TENG, which is of simplicity and attractiveness for flexible electronics.  相似文献   
78.
Sheng  Bao  Wenzhong  Shi  Wenzheng  Fan  Pengxin  Chen  Mingyan  Nie  Haodong  Xiang 《The Journal of supercomputing》2022,78(2):1903-1922
The Journal of Supercomputing - High-precision point cloud maps have drawn increasing attention due to their wide range of applications. In recent decades, point cloud maps are normally generated...  相似文献   
79.
The surface energy and surface stability of Ag nanocrystals (NCs) are under debate because the measurable values of the surface energy are very inconsistent, and the indices of the observed thermally stable surfaces are apparently in conflict. To clarify this issue, a transmission electron microscope is used to investigate these problems in situ with elaborately designed carbon‐shell‐capsulated Ag NCs. It is demonstrated that the {111} surfaces are still thermally stable at elevated temperatures, and the victory of the formation of {110} surfaces over {111} surfaces on the Ag NCs during sublimation is due to the special crystal geometry. It is found that the Ag NCs behave as quasiliquids during sublimation, and the cubic NCs represent a featured shape evolution, which is codetermined by both the wetting equilibrium at the Ag–C interface and the relaxation of the system surface energy. Small Ag NCs (≈10 nm) no longer maintain the wetting equilibrium observed in larger Ag NCs, and the crystal orientations of ultrafine Ag NCs (≈6 nm) can rotate to achieve further shape relaxation. Using sublimation kinetics, the mean surface energy of Ag NCs at 1073 K is calculated to be 1.1–1.3 J m?2.  相似文献   
80.
Surface functionality is an essential component for processing and application of metal–organic frameworks (MOFs). A simple and cost‐effective strategy for DNA‐mediated surface engineering of zirconium‐based nanoscale MOFs (NMOFs) is presented, capable of endowing them with specific molecular recognition properties and thus expanding their potential for applications in nanotechnology and biotechnology. It is shown that efficient immobilization of functional DNA on NMOFs can be achieved via surface coordination chemistry. With this strategy, it is demonstrated that such porphyrin‐based NMOFs can be modified with a DNA aptamer for targeting specific cancer cells. Furthermore, the DNA–NMOFs can facilitate the delivery of therapeutic DNA (e.g., CpG) into cells for efficient recognition of endosomal Toll‐like receptor 9 and subsequent enhanced immunostimulatory activity in vitro and in vivo. No apparent toxicity is observed with systemic delivery of the DNA–NMOFs in vivo. Overall, these results suggest that the strategy allows for surface functionalization of MOFs with different functional DNAs, extending the use of these materials to diverse applications in biosensor, bioimaging, and nanomedicine.  相似文献   
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