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排序方式: 共有277条查询结果,搜索用时 31 毫秒
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为了提高系统的易测试性,保证飞行安全,在该直升机操纵台硬件设计中,针对各个功能模块的特点,相应地采用了多种BIT(Build-in Test,机内测试)技术,如余度BIT、环绕BIT等技术,并在微控芯片软件中嵌入了自检测模块,全面完整地实现了系统的自检测;同时利用扩展flash存储芯片实时保存系统运行数据和测试信息,可通过串口上传至上位机,为故障分析提供了便利;采用Visual C++编程语言,结合专家系统开发了一套上位机检测软件,用于操纵台故障的智能诊断。 相似文献
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To achieve strong power coupling, a resonance-type magnetoelectric (ME) transducer with high quality factor is developed to achieve strong ME coupling. The ME transducer employs a type of iron–nickel-based ferromagnetic alloy with constant elasticity and piezoelectric Pb(Zr,Ti)O3 (PZT8) material. The dynamic magnetomechanical behavior of the ferromagnetic alloy is investigated. The result indicates that the strain coefficient of the ferromagnetic alloy at resonance achieves 557.07 nm/A due to the high effective mechanical quality factor of the alloy. The transducer is designed to operate as a half-wavelength, longitudinal resonator. The dynamic performance of the transducer is evaluated by measuring its electrical and vibrational characteristics. The results reveal that (1) the resonance of the transducer occurs at the frequency of 26.9336 kHz with a strain coefficient of 314.74 nm/A, an effective mechanical quality factor of 1600; (2) the ME voltage coefficient achieves 30.07 V/Oe (i.e., 375.875 V/cm Oe) at resonance; (3) the ME output power density at optimal load resistance of 25 kΩ achieves 0.956 mW/cm3 under 0.3 Oe root-mean-square AC magnetic field. The performances indicate that the transducer is promising for ME energy conversion application. 相似文献
4.
Qiuping Chen Qiuling Chen Daniel Milanese Monica Ferraris 《Microsystem Technologies》2009,15(12):1873-1877
A thermal assisted direct bonding (TADB) technique between structured glasses is proposed for micro-fluidic device fabrication.
The bonded glass pairs were characterized by optical microscopy, scanning electron microscopy (SEM), apparent shear strength
tests and Vickers hardness measurements across the bonded interface. The optimisation of TADB parameters on flat glasses and
on structured glasses was analysed. This technique is user-friendly and low cost, and can be considered for mass production
of glass-based micro-fluidic devices. 相似文献
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结合精益供应链理论,以价值作为方案决策要点,对工程建设项目价值分析进行研究,通过案例说明价值分析在工程建设项目中的应用流程。采用模糊质量功能展开法综合评价各方案的价值,并进行对比分析,找出价值最优方案。基于精益供应链的工程建设项目价值分析是一种行之有效的方案决策方法。 相似文献
7.
Qiuling Zou Qinghong Zhang Jingzhou Yang Aimee Cloutier Esteban Pena-Pitarch 《Computers & Industrial Engineering》2012
This paper presents a nonlinear inverse optimization approach to determine the weights for the joint displacement function in standing reach tasks. This inverse optimization problem can be formulated as a bi-level highly nonlinear optimization problem. The design variables are the weights of a cost function. The cost function is the weighted summation of the differences between two sets of joint angles (predicted posture and the actual standing reach posture). Constraints include the normalized weights within limits and an inner optimization problem to solve for joint angles (predicted standing reach posture). The weight linear equality constraints, obtained through observations, are also implemented in the formulation to test the method. A 52 degree-of-freedom (DOF) human whole body model is used to study the formulation and visualize the prediction. An in-house motion capture system is used to obtain the actual standing reach posture. A total of 12 subjects (three subjects for each percentile in stature of 5th percentile female, 50th percentile female, 50th percentile male and 95th percentile male) are selected to run the experiment for 30 tasks. Among these subjects one is Turkish, two are Chinese, and the rest subjects are Americans. Three sets of weights for the general standing reach tasks are obtained for the three zones by averaging all weights in each zone for all subjects and all tasks. Based on the obtained sets of weights, the predicted standing reach postures found using the direct optimization-based approach have good correlation with the experimental results. Sensitivity of the formulation has also been investigated in this study. The presented formulation can be used to determine the weights of cost function within any multi-objective optimization (MOO) problems such as any types of posture prediction and motion prediction. 相似文献
8.
机器人系统自适应鲁棒H∞跟踪控制器设计 总被引:2,自引:0,他引:2
为更好地解决机器人系统中存在的参数不确定和外部干扰的鲁棒控制问题,论文结合参数自适应方法,采用耗散性原理,设计了一种自适应鲁棒H∞跟踪控制器,解决了机器人系统同时存在参数不确定和外部干扰的干扰抑制问题。给出了此种自适应鲁棒H∞跟踪控制律存在的充分条件及设计方法,并通过典型算例说明了此类控制律的设计步骤。仿真结果表明,此法设计的控制器不仅对机器人系统可能受到的干扰具有较好的抑制能力,还对系统参数的不确定性具有一定的鲁棒性。 相似文献
9.
研究一类更具一般性的不确定性范数有界的多时滞非线性系统的输出反馈H∞控制问题。运用微分对策和耗散性原理,给出了这类问题可解的充分条件。章的要旨在于只要一对Riccati方程的解存在,就能确定出输出反馈控制律中的参数矩阵。典型算例说明了此类控制律的设计步骤,仿真结果表明,该方法对干扰输入具有较强的抑制能力。 相似文献
10.
Ningchang Wang Feng Jiang Xipeng Xu Nian Duan Qiuling Wen Xizhao Lu 《Ceramics International》2019,45(8):10310-10320
Due to its superior mechanical, optical and chemical properties, sapphire (α-Al2O3) is widely used in engineering, optics, medicine, and other scientific research fields. The atomic structure of sapphire gives rise to anisotropy in its mechanical properties, which affects the machinability of sapphire materials on different crystal planes. Different cutting directions will affect the wafer economy and surface quality achieved during wire sawing due to this anisotropy. In this study, the machinability of A-plane sapphire was investigated for diamond wire sawing in three different directions, following the C-plane, R-plane and M-plane. The results show that the direction following the M-plane could be the best direction for diamond wire sawing because this direction results in the minimal sawing forces, the lowest specific energy and the smallest volume of material that will need to be removed during subsequent processing. These characteristics correspond to the direction with the highest fracture strength since the material is removed by brittle machining. The force ratio for sawing in the direction of the R-plane is the smallest because this direction is associated with the minimum hardness and the lowest critical load for the transition from plastic to brittle removal of the workpiece material. The 3D height parameters show no obvious pattern among the three sawing directions. The mechanism of material removal is mainly brittle removal, with some plastic removal, and is obviously affected by the crystal orientation. 相似文献