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21.
In this study, electroactive polyimide microspheres (EPSs) based on conjugating segments of electroactive aminocapped aniline trimer as diamine and 4,4′‐(4,4′‐isopropylidenediphenoxy)‐bis(phthalic anhydride) as dianhydride were successfully prepared by electrospraying technology and characterized by time of flight mass spectroscopy, 1H‐NMR, Fourier transform infrared spectroscopy and cyclic voltammetry. The prepared electroactive polyimide was then dissolved in a suitable organic solvent (N,N‐dimethylformamide; N‐methyl‐2‐pyrrolidone) followed by electrospraying treatment under four different operational parameters (i.e. solution concentration, applied voltage, feeding rate and deposition distance) to give EPSs of various diameters. Moreover, EPSs deposited on the Pt electrode were tested in a 1.0 mol L?1 H2SO4 aqueous solution by cyclic voltammetry which showed an obvious redox peak similar to polyaniline. Copyright © 2011 Society of Chemical Industry  相似文献   
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The myriad of information communication technologies (ICTs) available today has changed the way students choose and use them. Specifically, individuals are increasingly relying on a mix of ICTs for communication to accomplish tasks. Yet, past studies on ICT use has largely assumed that people use a single ICT per task. We attempt to address this gap by focusing on the influence of individual differences on the choice of communication portfolio (a mix of ICTs) to accomplish learning tasks in school-based settings. Specifically, we focus on two dimensions of individual differences: learning styles and individuals’ perceptions. Results suggest that individual differences do have effects on the choice of communication portfolios to accomplish tasks. In particular, we found that students who preferred to learn by hearing tended to choose the complex communication portfolio to accomplish their tasks. Interestingly, our results also indicate that students preferred to use the simple communication portfolio when communication partners were perceived to be unavailable.  相似文献   
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Novice and skilled golfers took a series of golf putts with a standard putter (Exp. 1) or a distorted funny putter (consisting of an s-shaped and arbitrarily weighted putter shaft; Exp. 2) under instructions to either (a) take as much time as needed to be accurate or to (b) putt as fast as possible while still being accurate. Planning and movement time were measured for each putt. In both experiments, novices produced the typical speed-accuracy trade-off. Going slower, in terms of both the planning and movement components of execution, improved performance. In contrast, skilled golfers benefited from reduced performance time when using the standard putter in Exp. 1 and, specifically, taking less time to plan improved performance. In Exp. 2, skilled golfers improved by going slower when using the funny putter, but only when it was unfamiliar. Thus, skilled performance benefits from speed instructions when wielding highly familiar tools (i.e., the standard putter) is harmed when using new tools (i.e., the funny putter), and benefits again by speed instructions as the new tool becomes familiar. Planning time absorbs these changes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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This paper introduces a switching command-based whole-body operation method for humanoid robots. Humanoid robots are biped machines possessing multiple degrees of freedom (DOF). Due to the complexity of their multi-DOF structure, and the difficulty in maintaining postural stability, whole-body operation of humanoid robots is fundamentally different from traditional fixed-base manipulators or stable-base mobile manipulators. By studying the shifts in locus of attention between human body joints during task execution, we developed a switching command-based operation method that allows the operator to select only the necessary points of the humanoid robot's body for manipulation. Whole-body motion satisfying the desired movements of the selected points is generated using an inverse-kinematics motion generation scheme. This switching operation method enables flexible whole-body operation of humanoid robots using simple input devices. The proposed whole-body operation method is implemented as a teleoperation system using two 3-DOF joysticks to operate a 30-DOF humanoid robot (HRP-1S) developed in the Humanoid Robotics Project (HRP) of the Ministry of Economy, Trade, and Industry of Japan. Experiments teleoperating HRP-1S confirmed the effectiveness of our method.  相似文献   
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A method of kinematic analysis of the fingers using stereo-photogrammetry, referred to as the phalanx transformation technique, has been proposed. Functional methods were used to define the joint axes and subsequently each finger segments' anatomical coordinate system. Thirteen subjects were tested and the accuracy of the technique assessed. The average error across the three joints of the finger was found to be 0.6 mm, which translates to a 2.2% error in predicted joint reaction force when using a biomechanical model. The subjects were required to have sufficient movement in their joints to define the joint axes functionally. Some subjects of clinical interest can have a significantly reduced mobility owing to injury or pathology, therefore, the effect of calibration range of motion on accuracy was analysed. It was found that, for a range of motion typical of a subject with rheumatoid arthritis, the errors in predicted joint reaction force were < 7%. The accuracy of this technique compared favourably with others previously proposed and, considering the other errors inherent in modelling, those found in this study were deemed to be acceptable.  相似文献   
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Every year a number of young children are injured as a result of accidents that occur on board trains in Great Britain. These accidents range from being caught in internal doors, through to injuries caused by using seats. We describe our efforts to design a new set of safety signs in order to help prevent the occurrence of these types of accident. The research was funded under a Rail Safety and Standards Board (RSSB) managed UK Department for Transport research programme and was carried out in collaboration with Loughborough University. The study involved analysis of industry accident incidence data and running a set of classroom discussions with young school children (aged 5-10, n=210). The classroom discussions initially involved showing them examples of a new design prototype sign alongside existing train signs and gathering the requirements for new designs. A second set of classroom discussions with these children was used to evaluate the new signs based on the outcomes from earlier discussions. We describe our findings alongside a set of outline guidelines for the design of safety signs for young children. A final section considers the main methodological and other lessons learnt from the study, alongside study limitations and possibilities for future research.  相似文献   
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This paper introduces a framework for whole-body motion generation integrating operator's control and robot's autonomous functions during online control of humanoid robots. Humanoid robots are biped machines that usually possess multiple degrees of freedom (DOF). The complexity of their structure and the difficulty in maintaining postural stability make the whole-body control of humanoid robots fundamentally different from fixed-base manipulators. Getting hints from human conscious and subconscious motion generations, the authors propose a method of generating whole-body motions that integrates the operator's command input and the robot's autonomous functions. Instead of giving commands to all the joints all the time, the operator selects only the necessary points of the humanoid robot's body for manipulation. This paper first explains the concept of the system and the framework for integrating operator's command and autonomous functions in whole-body motion generation. Using the framework, autonomous functions were constructed for maintaining postural stability constraint while satisfying the desired trajectory of operation points, including the feet, while interacting with the environment. Finally, this paper reports on the implementation of the proposed method to teleoperate two 30-DOF humanoid robots, HRP-1S and HRP-2, by using only two 3-DOF joysticks. Experiments teleoperating the two robots are reported to verify the effectiveness of the proposed method.  相似文献   
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