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排序方式: 共有41条查询结果,搜索用时 15 毫秒
1.
The KHNP (Korea Hydro & Nuclear Power Co.) has developed a multipurpose nuclear safety analysis code called SPACE (the safety and performance analysis code) for nuclear power plants. SPACE code is a best-estimated two-phase three-field thermal-hydraulic analysis code used to analyze the safety and performance of pressurized water reactors. In this paper, LOFT (loss of fluid test) L9-3 experiment using the SPACE code was selected to confirm the capability of SPACE code and the results calculated by the SPACE code are compared with those measured through the experiment. The results were compared with the experimental data and those of the other code simulations. Throughout the simulation result, it was concluded that the SPACE code can effectively simulate LOFT L9-3 experiment.  相似文献   
2.
《Advanced Robotics》2013,27(3):247-267
We conducted a micro-gravity flight experiment on a space robotic arm, which is a part of the Reconfigurable Brachiating space Robot (RBR) unit arm developed by the authors. We used a 4-d.o.f. arm and an end-effector in the experiment. The airplane (MU-300) generates the micro-gravity environment for approximately 20 s in parabolic flight operation. After the flight, we conducted the corresponding ground experiments, and obtained the data of the motor current, servo control characteristics and manipulation performances, which were compared with the flight experiment data. Then, we conducted the numerical analysis of the 4-d.o.f. RBR arm based on the experiment results. In the analysis, we investigated feasibility of simulation model and identified model parameters. In this paper, we report the results of the flight experiments and numerical analysis.  相似文献   
3.
高层住宅是当今建筑发展的主流,针对现阶段高层住宅匮乏的公共交往空间的状况展开分析,在充分了解高层住宅公共交往空间设计人性化,生态性等基本原则的前提下,提出了高层住宅"立体式多层次"公共交往空间的设计方法,为以后高层住宅的公共交往空间设计提供理论依据,倡导建筑设计师创造出更舒适、生态、安全的公共交往空间。  相似文献   
4.
《Advanced Robotics》2013,27(7):771-792
We introduced the concept of C-space entropy recently as a measure of knowledge of configuration space (C-space) for sensor-based exploration and path planning for general robot–sensor systems. The robot plans the next sensing action to maximally reduce the expected C-space entropy, also called the Maximal expected Entropy Reduction (MER) criterion. The resulting view planning algorithms showed significant improvement of exploration rate over physical space-based criteria. However, this expected C-space entropy computation made two idealized assumptions: (i) that the sensor field of view (FOV) is a point and (ii) that there are no occlusion (or visibility) constraints, i.e., as if the sensor can sense through the obstacles. We extend the expected C-space entropy formulation where these two assumptions are relaxed, and consider a range sensor with non-zero volume FOV and occlusion constraints, thereby modeling a realistic range sensor. Planar simulations and experimental results on the SFU Eye-in-Hand system show that the new formulation results in further improvement in C-space exploration efficiency over the point FOV sensor-based MER formulation.  相似文献   
5.
The surface of a polyhedral oligomeric silsesquioxane-polyurethane copolymer has been characterized in situ using X-ray photoelectron spectroscopy before and after exposure to incremental fluences of oxygen atoms produced by a hyperthermal oxygen atom source. The data indicate that the atomic oxygen initially attacks the cyclopentyl groups that surround the polyhedral oligomeric silsesquioxane cage most likely resulting in the formation and desorption of CO and/or CO2 and H2O from the surface. The carbon concentration in the near-surface region is reduced from 72.5 at.% for the as-entered surface to 37.8 at.% following 63 h of O-atom exposure at a flux of 2.0 × 1013 O atom/cm2-s. The oxygen and silicon concentrations are increased with incremental exposures to the O-atom flux. The oxygen concentration increases from 18.5 at.% for the as-entered sample to 32.6 at.% following the 63-h exposure, and the silicon concentration increases from 8.1 to 11.1 at.% after 63 h. The data reveal the formation of a silica layer on the surface, which serves as a protective barrier preventing further degradation of the polymer underneath with increased exposure to the O-atom flux.  相似文献   
6.
混凝土中邻近集料表面最近间距分布的计算机模拟   总被引:6,自引:0,他引:6  
混凝土中邻近集料问界面过渡区的相互影响程度、混凝土中原生裂纹的尺度范围以及中心质假说中集料效应圈的范围等都涉及到混凝土中最邻近集料表面间距分布的问题。由于常规的实验方法无法给出混凝土中集料空间分布的信息,同时以往的计算机模拟方法由于采用随机分布方式分布粒子,导致无法得到较高集料体积分数的模型混凝土结构,而采用具有粒子动态混合密实功能的SPACE系统,模拟了高集料体积分数混凝土的结构。在假定模型混凝土中集料的最小粒径为1mm的前提下,以符合Fuller分布为例,研究了模型混凝土中集料粒径分布和集料体积分数对邻近集料表面最近间距分布的影响。  相似文献   
7.
张磊  张娜  刘新  钟耀祖 《集成技术》2013,2(5):22-29
二维快速自旋回波(Two Dimensional Turbo Spin Echo,2D TSE)是目前临床应用十分广泛的一项成像技术。通 过与隔层扫描技术相结合,2D TSE 已在短时间内迅速应用于整个大脑的成像。由于射频能量吸收率(Specific Absorption Rate,SAR)以及 T2 衰减的影响,TSE 数据采集效率难以满足三维成像的要求。SPACE(Sampling Perfection with Application-optimized Contrasts by using different flip angle Evolutions)在 TSE 的基础上,采用非选择回聚脉冲和可变翻转 角,克服了 SAR 和 T2 衰减的影响,满足了临床对三维 TSE 的需求。文章将详细介绍 SPACE 的基本原理,分析成像参 数对图像质量的影响,并简单介绍 SPACE 在人体各个部位的临床应用及其前景展望。  相似文献   
8.
张杰 《中华民居》2012,(3):85+82
展示,顾名思义,是"以综合物、人、场等要素最佳空间关系为手段,以传达特定信息为目的的展览、演示活动(1)"。由于在特定的环境中,不同于其他纯粹的展示空间,造就了别具特色的教学空间内的展示方式。文章以南开大学主楼为研究对象,重点研究和分析了其流线、灯光、色彩、辅助设施等方面,探讨了教学空间内的展示设计意匠。  相似文献   
9.
《Advanced Robotics》2013,27(4):467-488
This paper discusses a vision-based approach to implement task-level control in flexible-link manipulators. The proposed approach emphasizes the advantage of using vision in the control of flexible manipulators. It is pointed out that taking advantage of the inherent robustness, implementation of an image-based visual servo can be regarded as a synthetic solution to precise task-level control of flexible manipulators. This approach is implemented in a three-dimensional flexible-link manipulator. The implementation makes good use of filters in decoupling task-level control and vibration suppression control. Moreover, we point out that although the robustness of the approach can help to overcome the difficulty in control resulting from the complex measurement of the link's elastic deformation, it lacks in capability of tip trajectory specification. This problem is analyzed in this research and it leads to the proposal for the integration of the image interpolation technique. This technique makes the proposed approach adequate for tasks involved with complex tip trajectories. For flexible-link manipulators, the proposed approach with the remedy is the first vision-based synthetic solution that attempts to make a flexible manipulator usable for a practical task.  相似文献   
10.
《Advanced Robotics》2013,27(5):567-590
Performing complex assembly tasks with robots requires fine-motion planners able to cope with uncertainty and contact motions, and this is a recognized difficult issue. This paper proposes a method to predict the behavior of motions under contact uncertainty in order to check the feasibility of paths generated by gross-motion planning algorithms from a nominal model of the environment. This pragmatical approach enables the extension of gross-motion planning techniques to constrained-motion planning problems, ensuring the feasibility of the task despite the uncertainties. The approach has been implemented for assembly tasks in the plane with three degrees of freedom.  相似文献   
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