全文获取类型
收费全文 | 152篇 |
免费 | 7篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 28篇 |
金属工艺 | 11篇 |
机械仪表 | 4篇 |
能源动力 | 5篇 |
轻工业 | 20篇 |
无线电 | 30篇 |
一般工业技术 | 37篇 |
冶金工业 | 16篇 |
自动化技术 | 7篇 |
出版年
2023年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 11篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 2篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
排序方式: 共有159条查询结果,搜索用时 109 毫秒
151.
Beom-hoan O Heung Ro Choo Hyung Mun Kim Jeong Soo Kim Dae Kon Oh Hye Rim Kim Hong Man Kim Kwang Eui Pyun 《Photonics Technology Letters, IEEE》1997,9(2):164-166
Spontaneous emission spectra below threshold were measured from the side wall of InGaAs QW laser diodes to extract laser design parameters such as cavity length dependence of gain, linewidth enhancement factor, and serial resistance. The threshold current varies according to the change of cavity length, and thus, the lasing peak shifts and the serial resistance changes. It is interesting that the linewidth enhancement factor, however, is not deteriorated by shortening cavity length. The short cavity length would rather improve the linewidth enhancement factor mainly by shifting the lasing peak to smaller wavelength side, where the linewidth enhancement factor is inherently low. 相似文献
152.
Kwang-ki Baek Su-il Pyun Jong-sang Kim 《Metallurgical and Materials Transactions A》1988,19(7):1721-1726
In the present work the effects of wear processes on enhanced hydrogen evolution from mild steel have been studied. A wear-production
system has been employed in which a wear test and a hydrogenextraction measuring process were conducted sequentially at 19
°C. The amount of hydrogen evolved due to the wear process increased with both the sliding time and the magnitude of the applied
load in the wear test. The hydrogen extraction measurements enable us to quantitatively distinguish clearly the contribution
of removal of highly hydrogen-segregated regions as wear debris and the contribution of frictional heat to the wear-enhanced
hydrogen evolution using a simplified mathematical model. It is suggested that the wear-enhanced hydrogen evolution from mild
steel is due mainly to removal of highly hydrogen-segregated regions near the steel surface. Frictional heat generated during
the wear test contributes to the acceleration of hydrogen evolution only in a minor scale. The major conclusion is that hydrogen
segregated to the dislocations present in the Hertzian stressed area near the contact surface is subsequently released as
wear debris and also by the thermal diffusion due to the frictional heat.
Formerly with the Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Seoul,
Korea. 相似文献
153.
Effects of carbon, nitrogen and phosphorous on the intergranular corrosion and the stress-corrosion cracking of iron Experiments without stress, with constant load, or with constant strain rate were performed in boiling 55% Ca(NO3)2 solution (115°C) to elucidate the effects of carbon, nitrogen and phosphorous on the intergranular corrosion (IC) and stress-corrosion cracking (SCC) of iron. The original material contained 20 to 40 ppm C, 17 ppm N, and 20 ppm P. One batch of this material was normalized only, a second batch was also decarburized up to under 10 ppm C prior to normalizing, and a third batch was decarburized, and then nitrided up to 140 to 220 ppm N prior to normalizing. Some of the specimens were tempered at 550°C for one month. All normalized specimens showed no susceptibility to IC at applied potentials from 800 to 1000 mV (SHE). In contrast, specimens tempered at 550°C were very susceptible to IC, which was observed even at 200 mV after decarburization. Auger-spectra of intergranular fracture surfaces of a tempered specimen produced at liquid-nitrogen temperature revealed grain boundary segregation of P (about 10 atomic %). The as-normalized specimens fractured intergranularly within 1 to 2 h, when held at constant load of 0.8 and 0.9 of ultimate tensile strength (UTS), and 0 mV. By contrast, under identical conditions, the decarburized specimens and the nitrided specimens did not fracture in 30 d. The fracture energy tested with the constant strain-rate method at 0 mV, as compared with experiments in oil, was strongly lowered in the as-normalized specimens and significantly lowered in the nitrided specimens. The values of fracture energy obtained for the decarburized specimens were mostly similar to those in oil at 115°C. Only some of the decarburized specimens showed substantial decreases in fracture energy. However, the decarburized and tempered specimen showed an even larger decrease in fracture energy, with intergranular fracture mode. 相似文献
154.
Jin-Hee Lee Hyung-Sup Yoon Byung-Sun Park Chul Soon Park Sang-Soo Choi Kwang-Eui Pyun 《ETRI Journal》1996,18(3):171-179
Fully passivated low noise AlGaAs/InGaAs/GaAs pseudomorphic (PM) HEMT with wide head T-shaped gates were fabricated by dose split electron beam lithography (DSL). The dimensions of gate head and footprint were optimized by controlling the splitted pattern size, dose, and spaces of each pattern. We obtained stable T-shaped gate of 0.15 μm gate length with 1.35 μm-wide head. The maximum extrinsic transconductance was 560 mS/mm. The minimum noise figure measured at 18 GHz at Vds = 2 V and Ids = 17 mA was 0.41 dB with associated gain of 8.19 dB. At 12 GHz, the minimum noise figure and an associated gain were 0.26 and 10.25 dB, respectively. These noise figures are the lowest values ever reported for GaAs-based HEMTs. These results are attributed to the extremely low gate resistance of wide head T-shaped gate having a ratio of the head to footprint dimensions larger than 9. 相似文献
155.
Determination of the apparent diffusivity and effective solubility of hydrogen in pure iron at room temperature by an electrochemical hydrogen permeation technique. Evidence that the effect of vacancies as hydrogen trap sites on hydrogen diffusivity and solubility in pure iron at room temperature is stronger than the influence of the dislocations. 相似文献
156.
157.
New Infrared Transmitting Material via Inverse Vulcanization of Elemental Sulfur to Prepare High Refractive Index Polymers
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jared J. Griebel Soha Namnabat Eui Tae Kim Roland Himmelhuber Dominic H. Moronta Woo Jin Chung Adam G. Simmonds Kyung‐Jo Kim John van der Laan Ngoc A. Nguyen Eustace L. Dereniak Michael E. Mackay Kookheon Char Richard S. Glass Robert A. Norwood Jeffrey Pyun 《Advanced materials (Deerfield Beach, Fla.)》2014,26(19):3014-3018
158.
Strain BH5 was isolated from naturally fermented Kimchi and identified as a bacteriocin producer that has bactericidal activity against Micrococcus flavus ATCC 10240. Strain BH5 was identified tentatively as Lactococcus lactis by API test. Lactococcus lactis BH5 showed a broad spectrum of activity against most of the nonpathogenic and pathogenic microorganisms tested by the modified deferred method. The activity of lacticin BH5, named tentatively as the bacteriocin produced by L. lactis BH5, was detected at the mid-log growth phase, reached its maximum during the early stationary phase, and decreased after the late stationary phase. Lacticin BH5 also showed a relatively broad spectrum of activity against nonpathogenic and pathogenic microorganisms as tested by the spot-on-lawn method. Its antimicrobial activity on sensitive indicator cells was completely destroyed by protease XIV. The inhibitory activities of lacticin BH5 were detected during treatments up to 100 degrees C for 30 min. Lacticin BH5 was very stable over a pH range of 2.0 to 9.0 and was stable with all the organic solvents examined. It demonstrated a typical bactericidal mode of inhibition against M. flavus ATCC 10240. The apparent molecular mass of lacticin BH5 was estimated to be in the region of 3 to 3.5 kDa, by the direct detection of bactericidal activity after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 相似文献
159.
The effect of water on heating wheat starch-water mixtures of water content (between 2.8% and 90%) has been observed by differential scanning calorimetry. Four endothermic transitions were observed for wheat starches heated in the presence of limited water (moisture levels of 40,50%). These transitions appears to be due to melting of amylopectin crystallites, amylose-lipid, and amylose. The heat decomposition temperature range of wheat starch were 253-302°C and the plasticization effect according to the amount of water was small. The melting temperature obtained by extrapolation to zero volunme fraction of water were 234°C for M1 DSC endotherm, 254.3°C for M2 DSC endotherm, 267.8°C for M3 DSC endotherm. 相似文献