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11.
秦鲜  周陶然 《移动信息》2023,45(10):86-88
在教育部全面推广“学位证书+某些职业技能等级证书”(简称1+X证书)制度的情况下,中职计算机应用技术专业的教学应该更加完善。教师应主动引进新的教学观念和教学方法。文中深入分析了“1+X”证书制度下的计算机应用专业“岗课赛证”融通体系,对计算机应用专业未来的教学实践与发展提出了一些建议,并探索了中职院校实施“1+X”证书制度的改革路径。  相似文献   
12.
The static balancing of a spatial 6-degree-of-freedom (6-DoF) decoupling parallel mechanism is discussed in this paper. Two traditional approaches (using counterweights and the springs) are used to statically balance the mechanism. Due to the existence of their shortcomings, a hybrid approach is proposed based on the static balancing of the mechanism. The main feature of this mechanism is that the 3-DoF rotating part can be static balancing itself, which means that its mass has no effect on the gravity balancing of the system, for any configuration of the mechanism, so the rotating part can be considered as a whole and the calculation is simplified. Finally, examples and dynamic analysis corresponding to the three balancing methods are given to illustrate the results.  相似文献   
13.
Formotex腈纶涤纶混纺纱的生产   总被引:1,自引:1,他引:1  
赵博  石陶然 《棉纺织技术》2005,33(12):45-47
介绍了Formotex纤维的性能特征,Formotex纤维与腈纶涤纶混纺纱的开发应针对Formotex纤维的特性,纺纱前进行预处理,同时提高车间相对湿度,以减少静电现象;为实现充分开松和混和均匀,减轻打击力度,采用低速度、多分梳、少打击、轻定量的工艺原则.  相似文献   
14.
单站多外辐射源雷达定位系统利用多组双基距(BR)和双基距变化率(BRR)量测值对多运动目标定位.量测偏差的存在使得定位性能下降,对此该文提出一种基于迭代后验关联最小二乘估计的联合误差校正和目标定位算法.首先引入辅助变量对BR和BRR非线性观测方程伪线性化,建立目标参数和偏差的联合估计方程.其次,利用辅助变量和目标参数之间的关系构建新的等式方程设计关联最小二乘算法,并采用后验迭代校正固定偏差进一步提高定位精度和全局收敛性.最后对算法的理论误差和全局收敛性进行了分析,仿真结果显示:所提算法具有较好的全局收敛性且目标定位性能达到克拉美罗下界.  相似文献   
15.
总结现有的砼本构关系,经过试验和理论分析,修定了基于弹塑性理论的砼本构关系;确定了四参数强度准则的参数,使之适合于自应力钢管轻骨料砼的核心砼.  相似文献   
16.
One of the core values of urban wilderness construction is to restore the structures and functions of biological communities in fragmented urban habitats, and enable the stability and ecological succession of native communities with low human intervention. The paper discusses the design principles and technical methodologies in active urban rewilding by the example of Shanghai Urban Biodiversity Education Base project. Aiming to restore urban biodiversity and enrich the technical and theoretical research of urban wilderness construction and Nature-based Solutions, this project conducted habitat division, native species introduction, natural community construction, ecological benefit assessment, etc. In a year and a half, 260 native plant species, 255 insect species, 7 amphibian and reptile species, 71 bird species, and 6 mammal species were recorded within the 1.7 hm2 project site, showing higher biodiversity and density of animal populations than unrestored consructed forests surrounding. Along with the spontaneous progressive succession of the plant communities, the project has achieved good results. The technical approaches proposed in the project can be broadly applied in design and construction of country parks, wildlife habitats, ecological corridors / networks, and environmental education bases.  相似文献   
17.
Seismic energy decays while propagating subsurface, which may reduce the resolution of seismic data. This paper studies the method of seismic energy dispersion compensation which provides the basic principles for multi-scale morphology and the spectrum simulation method. These methods are applied in seismic energy compensation. First of all, the seismic data is decomposed into multiple scales and the effective frequency bandwidth is selectively broadened for some scales by using a spectrum simulation method. In this process, according to the amplitude spectrum of each scale, the best simulation range is selected to simulate the middle and low frequency components to ensure the authenticity of the simulation curve which is calculated by the median method, and the high frequency component is broadened. Finally, these scales are reconstructed with reasonable coefficients, and the compensated seismic data can be obtained. Examples are shown to illustrate the feasibility of the energy compensation method.  相似文献   
18.

机载外辐射源雷达系统中,部署在飞机上的观测站传感器位置无法精确获知,观测站位置误差将严重影响目标定位精度。对此,该文提出一种观测站位置误差下多基外辐射源雷达3维定位代数解算法。该算法首先利用辅助变量将非线性双基距离和差(BRD)观测方程进行线性化,构造伪线性目标估计模型。然后将观测站位置量测噪声的统计特性融入定位算法,提出一种改进两步加权最小二乘(TS-WLS)算法实现观测站位置误差下外辐射源雷达目标定位。最后推导了克拉美罗下界(CRLB)和算法的理论误差。仿真结果显示,在适中的BRD量测误差和观测站位置误差下,所提算法的目标定位性能能够达到CRLB。

  相似文献   
19.
Railway alignment optimization is considered one of the most complicated and time‐consuming problems in railway planning and design. It requires searching among the infinite potential alternatives in huge three‐dimensional (3D) search spaces for a near‐optimal alignment, while considering complex constraints and a nonlinear objective function. In mountainous regions, the complex terrain and constructions require additional and more complex constraints than in topographically simpler regions. In this paper, the authors solve this problem with an algorithm based on a 3D distance transform (3D‐DT). Compared with previous two‐dimensional distance transform (2D‐DT) methods developed in this field, the feasible search spaces of 3D‐DT are greatly increased. Consequently, this new method can find more alternatives with higher qualities. In this approach, an erythrocyte‐shaped 3D neighboring mask is developed to narrow local search spaces and speed up the search process. Besides, a stepwise‐backstepping strategy is designed to dynamically determine feasible 3D search spaces and efficiently search the study area. During the 3D‐DT search process, multiple constraints, including geometric, construction, and location constraints, are effectively handled. After the 3D‐DT search, a genetic algorithm is employed to optimize the 3D‐DT paths into final alignments. Finally, this novel approach is applied to an actual case in a complex mountainous region. The comprehensive cost of the best solution generated by 3D‐DT is 16% below a manual solution produced by very experienced human designers. Furthermore, the total number of feasible alternatives found by 3D‐DT is 4.3 times greater than by 2D‐DT. The comprehensive cost of the best 3D‐DT solution is 10% below the best one generated by 2D‐DT.  相似文献   
20.
Flexible interconnects are one of the key elements in realizing next‐generation flexible electronics. While wire bonding interconnection materials are being deployed and discussed widely, adhesives to support flip‐chip and surface‐mount interconnections are less commonly used and reported. A polyurethane (PU)‐based electrically conductive adhesive (ECA) is developed to meet all the requirements of flexible interconnects, including an ultralow bulk resistivity of ≈1.0 × 10?5 Ω cm that is maintained during bending, rolling, and compressing, good adhesion to various flexible substrates, and facile processing. The PU‐ECA enables various interconnection techniques in flexible and printed electronics: it can serve as a die‐attach material for flip‐chip, as vertical interconnect access (VIA)‐filling and polymer bump materials for 3D integration, and as a conductive paste for wearable radio‐frequency devices.  相似文献   
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