全文获取类型
收费全文 | 154篇 |
免费 | 1篇 |
专业分类
电工技术 | 37篇 |
化学工业 | 18篇 |
机械仪表 | 15篇 |
建筑科学 | 1篇 |
能源动力 | 3篇 |
轻工业 | 5篇 |
石油天然气 | 1篇 |
无线电 | 43篇 |
一般工业技术 | 20篇 |
冶金工业 | 8篇 |
自动化技术 | 4篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2018年 | 8篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 13篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 11篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 8篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有155条查询结果,搜索用时 156 毫秒
91.
Jung-Ik Ha Seung-Ki Sul 《Industry Applications, IEEE Transactions on》1999,35(1):45-51
This paper describes a new scheme to find the rotor flux angle from stator voltages and currents by injecting high-frequency signal. The signal is not a rotating one, but a fluctuating one at a synchronous rotating reference frame with the fundamental stator frequency. When the estimated rotor flux angle coincides with the actual angle, the proposed method makes virtually no ripple torque, no vibration and less audible noise caused by the injected signal. The difference of impedances between the flux axis and the quadrature axis at high-frequency signal injection on the rotor flux angle is explained by the equivalent circuit equation of the induction machine. The difference is verified by experiments on the test motors at various testing conditions. The sensorless field-orientation algorithm is proposed, and the experimental results clarify the satisfactory operation of the algorithm with 150% load torque at zero stator frequency 相似文献
92.
A new efficient tuning method for proportional-integral (PI) controllers is proposed using overdamped closed-loop dynamics of the system. In line with other direct-synthesis and IMC methods, this new approach uses the desired closed-loop response to satisfy usual control and tuning objectives, but unlike the most other tuning methods hitherto-reported for PID controllers, it does not require that a process model be identified. Yet this new direct-synthesis (NDS) method is capable of making the controller perform the dual control functions of both good set-point tracking and disturbance rejection. Furthermore, it turns out that the new tuning method works equally well for difficult cases like large time delay and nonminimum phase processes. Finally, it can be said that this NDS method can be easily implemented and understood by the plant operating personnel because it has been developed emphasizing its on-site utility. 相似文献
93.
Osteoclasts (OCs), which are responsible for bone resorption, play a critical role in cholesterol-induced bone loss and recent studies have suggested that various micro-RNAs (miRs) contribute to modulating OCs. We hypothesized that 7-ketocholesterol (7-KC), a metabolite responsible for cholesterol-induced bone loss, induces miR-107-5p, which affects OCs. Overexpression and knock-down of miR-107-5p were performed using miR-107-5p mimic and anti-miR-107-5p, respectively. The effects of miR-107-5p on OCs were analyzed by tartrate-resistant alkaline phosphatase staining, qPCR, and Western blot. MiR-107-5p was upregulated after 7-KC exposure in receptor activator of nuclear factor kappa-Β ligand-stimulated OCs. Furthermore, miR-107-5p upregulation was also observed in tibiae from an atherogenic diet-fed mice compared with mice fed with a normal diet. MiR-107-5p overexpression enhanced the area and number of OCs, whereas inhibiting the endogenous expression of miR-107-5p generated by 7-KC had the opposite effect. Among the possible candidates, mitogen-activated protein kinase phosphatase-1, a stress-responsive dual-specificity phosphatase that inactivates mitogen-activated protein kinase (MKP1), has been proven to be a target gene of miR-107-5p, as demonstrated by the direct interaction between miR-107-5p and the 3′-untranslated region of MKP1. Collectively, our findings demonstrate that 7-KC-induced miR-107-5p promotes differentiation and function of OCs by downregulating MKP1. 相似文献
94.
Russian Engineering Research - A method is proposed for analysis of the stress–strain state of a permanent joint in end mills, using SolidWorks/Simulation software. 相似文献
95.
Russian Engineering Research - Developments in the assembly and welding of large railroad-car components are considered. The introduction of a new aluminum-alloy freight-car body is discussed. 相似文献
96.
97.
Ju Hyung We Heon Bok Lee Sun Jin Gim Gyung Soo Kim Kukjoo Kim Kyung Cheol Choi Onejae Sul Byung Jin Cho 《Journal of Electronic Materials》2012,41(6):1170-1176
We propose a method that allows us to evaluate the thermal conductivity of a conductive material that has thickness on the order of microns. The key feature of the proposed method is use of a complete thermoelectric device with electrodes and a substrate, while conventional methods measure the temperature gradient of thermoelectric materials directly without electrodes. The measured thermal conductivity of a ZnSb film annealed at 380°C in N2 ambient for 16?min to 26?min is 1.2?W/m?K to 1.4?W/m?K. The measurement shows that thermoelectric film prepared by a screen-printing technique has lower thermal conductivity than bulk material (2.2?W/m?K to 2.4?W/m?K) because the screen-printing technique generates high porosity in the film. The lower measured thermal conductivity of the porous films compared with bulk material supports the reliability of the proposed measurement method. 相似文献
98.
Discrete track magnetic recording media with a 60 nm track pitch and prewritten servo patterns were fabricated and tested for read/write performance, and a feasibility analysis of the embedded servo was performed. The fabrication process consisted of ultraviolet nanoimprint lithography (UV-NIL) and sequential ion beam etching on a conventional perpendicular magnetic recording medium. Magnetic patterns were written to the fabricated tracks at 700 kilo flux changes per inch (kFCI) using a spin stand and were read using magnetic force microscopy (MFM), with a resulting signal-to-noise ratio (SNR) of 12.15 dB. The servo pattern was also visualized with MFM. These results demonstrated the feasibility of writing to a 30 nm wide discrete data track and the workability of the embedded servo pattern. 相似文献
99.
The strength of gear hobs in cutting worm gears is calculated by the finite-element method, on the basis of SolidWorks/Simulation software. 相似文献
100.
Kim S Kim JC Sul D Hwang SW Lee SH Kim YH Tae G 《Journal of nanoscience and nanotechnology》2011,11(5):4586-4591
Capsaicin might be an effective pharmacological agent for the treatment of discogenic back pain due to its effect on pain control neuronal degeneration. Therefore, capsaicin-loaded nano- and micro-particles for sustained release were formulated by nano-precipitation or oil-in-water single emulsion solvent evaporation/extraction method. First, the capsaicin-loaded PLGA nanoparticles were prepared by nano-precipitation method. By increasing the volume of oil-water ratio from 1:2 to 1:5, slight changes in size from 162 +/- 3 nm to 153 +/- 3 nm and in drug loading efficiency from 25% to 20% were observed, whereas the drug release period was significantly changed from 11 days for 1:2 to 5 days for 1:5 ratio. To get a more sustained release, a modified single emulsion method was applied with three kinds of biocompatible polymers (PLLA, PLGA, and PCL). Among them, PLLA particles showed a much sustained release profile than PLGA or PCL ones with the similar size. For PLLA particles, particles size and drug encapsulation efficiency increased as the oil/water ratio decreased, and the bigger particles showed the slower release profiles as well as the higher drug-loading efficiency, thus about 1 month release was obtained with 800 nm particles. In conclusion, formulation for the controlled release of capsaicin from 1 week to 1 month was prepared by using biocompatible nanoparticles. 相似文献