全文获取类型
收费全文 | 46篇 |
免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 2篇 |
金属工艺 | 1篇 |
建筑科学 | 2篇 |
能源动力 | 3篇 |
轻工业 | 4篇 |
无线电 | 11篇 |
一般工业技术 | 9篇 |
冶金工业 | 13篇 |
自动化技术 | 1篇 |
出版年
2021年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2011年 | 3篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2002年 | 3篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有48条查询结果,搜索用时 15 毫秒
1.
Aoki K.. Kondo J.. Iwata Y.. Hamajima A.. Ejiri T.. Mitomi O.. Minakata M.. 《Lightwave Technology, Journal of》2007,25(7):1805-1810
We propose a small-footprint X-cut thin-sheet lithium niobate optical modulator with high-speed and low-driving-voltage characteristics. Since an optical waveguide is folded by a mirror placed at one edge of the modulation chip, the chip can be shortened by about half. In addition, a wide modulation bandwidth can be achieved, because the path-length difference between the optical waveguide and the coplanar-waveguide (CPW) electrode is decreased to as short as possible by placing the CPW electrode as far as possible along the optical waveguide in the folded portion, and the microwave effective index is set to realize effective velocity matching between the lightwave and the microwave. A small footprint of 1.78 times 29 mm, a low half-wave voltage of 2.0 V at dc, and a 3-dBe modulation bandwidth of 20 GHz were obtained. 相似文献
2.
The authors have demonstrated photochemical deposition of aluminum oxides from Trimethylaluminum (TMA) and N2O by using a pulsed ArF excimer laser (193 nm). Both TMA and N2O are efficiently photodissociated by the 193 nm light. The films are grown on Si and InP wafers contained in a low pressure
flowing cell with a heated substrate. The incident laser beam is focused and parallel to the substrate surface. Typical deposition
rates are 80–150 A/min. Stripes of aluminum oxide 30 mm wide are uniformly grown on 7.5 cm Si-wafers. The film composition
and purity have been investigated using Auger and Infra-red spectroscopy analysis. Surprising results are the relatively low
concentration of carbon. Refractive index and thickness have been determined by an ellipsometer. Typical values for the films
are 1.54–1.62. Metal-oxide-semiconductor capacitors have been fabricated and characterized. The C-V curves for n-InP/aluminum
oxide have clockwise hysteresis, and minimum loop width is less than 0.5 V. The surface state densities are 1 × 1011 cm-2 eV−1 at the mid band gap. 相似文献
3.
Jungo Kondo Aoki K. Kondo A. Ejiri T. Iwata Y. Hamajima A. Mori T. Mizuno Y. Imaeda M. Kozuka Y. Mitomi O. Minakata M. 《Photonics Technology Letters, IEEE》2005,17(10):2077-2079
We present a novel thin-sheet X-cut LiNbO/sub 3/ optical modulator structure which can be fabricated by precise polishing and lapping to obtain a thinner LiNbO/sub 3/ substrate for a lower driving voltage in addition to velocity matching and impedance matching. We demonstrated that the fabricated modulator had a driving voltage V/spl pi/ of 2 V and zero chirp for 40-Gb/s operation and had a high potential for suppressed dc drift, and long-term reliability. 相似文献
4.
Westerhoff P Mezyk SP Cooper WJ Minakata D 《Environmental science & technology》2007,41(13):4640-4646
Pulse radiolysis experiments were conducted on dissolved organic matter (DOM) samples isolated as hydrophobic and hydrophilic acids and neutrals from different sources (i.e., stream, lake, wastewater treatment plant). Absolute bimolecular reaction rate constants for the reaction of hydroxyl radicals (*OH) with DOM (k*(OH), DOM) were determined. k*(OH, DOM) values are expressed as moles of carbon. Based on direct measurement of transient DOM radicals (DOM*) and competition kinetic techniques, both using pulse radiolysis, the k*(OH, DOM) value for a standard fulvic acid from the Suwannee River purchased from the International Humic Substances Society was (1.60 +/- 0.24) x 10(8) M(-1) s(-1). Both pulse radiolysis methods yielded comparable k*(OH, DOM) values. The k*(OH, DOM) values for the seven DOM isolates from different sources ranged from 1.39 x 10(8) M(-1) s(-1) to 4.53 x 10(8) M(-1) s(-1), and averaged 2.23 x 108 M(-1) s(-1) (equivalent to 1.9 x 10(4) (mgC/L)(-1) s(-1)). These values represent the first direct measurements of k*(OH, DOM,) and they compare well with literature values obtained via competition kinetic techniques during ozone or ultraviolet irradiation experiments. More polar, lower-molecular-weight DOM isolates from wastewater have higher k*(OH, DOM) values. In addition, the formation (microsecond time scale) and decay (millisecond time scale) of DOM* transients were observed for the first time. DOM* from hydrophobic acids exhibited broader absorbance spectra than transphilic acids, while wastewater DOM isolates had narrower DOM* spectra more skewed toward shorter wavelengths than did DOM* spectra for hydrophobic acids. 相似文献
5.
Effect of different methods of internal thoracic artery harvest on pulmonary function 总被引:1,自引:0,他引:1
BACKGROUND: In several clinical studies, internal thoracic artery (ITA) grafting for myocardial revascularization has been identified as increasing the risk of postoperative pulmonary complications. This study was designed to determine whether the technique used to harvest the ITA has an effect on postoperative pulmonary function. METHODS: Seventy-nine consecutive patients undergoing coronary artery bypass grafting using the left ITA were compared with patients undergoing coronary artery bypass grafting using saphenous vein grafts only. Two methods of ITA harvesting were used: (1) incision of the endothoracic fascia dissected off the ITA as a skeletonized vessel (group 1, n = 33) and (2) mobilization of the ITA as a wide musculofascial pedicle (group 2, n = 46). Thirty-two patients underwent coronary artery bypass grafting using saphenous vein grafts only (group 3). Pulmonary function tests were performed between postoperative days 20 and 30. RESULTS: The postoperative values of forced vital capacity were reduced in patients in all groups (p < 0.0001). The ratios of postoperative to preoperative forced vital capacity were 84% in group 1, 77% in group 2, and 84% in group 3. The reduction in group 2 was significant compared with group 1 (p < 0.05) and group 3 (p < 0.05). CONCLUSIONS: Postoperative pulmonary dysfunction was significantly greater in patients who underwent wide musculofascial pedicle dissection of the ITA compared with skeletonization of the artery. Thus, of the two techniques, the latter may be the method of choice with regard to lowering the incidence of postoperative pulmonary dysfunction. 相似文献
6.
The hydroxyl radical (HO(?)) is a strong oxidant that reacts with electron-rich sites on organic compounds and initiates complex radical chain reactions in aqueous phase advanced oxidation processes (AOPs). Computer based kinetic modeling requires a reaction pathway generator and predictions of associated reaction rate constants. Previously, we reported a reaction pathway generator that can enumerate the most important elementary reactions for aliphatic compounds. For the reaction rate constant predictor, we develop linear free energy relationships (LFERs) between aqueous phase literature-reported HO(?) reaction rate constants and theoretically calculated free energies of activation for H-atom abstraction from a C-H bond and HO(?) addition to alkenes. The theoretical method uses ab initio quantum mechanical calculations, Gaussian 1-3, for gas phase reactions and a solvation method, COSMO-RS theory, to estimate the impact of water. Theoretically calculated free energies of activation are found to be within approximately ±3 kcal/mol of experimental values. Considering errors that arise from quantum mechanical calculations and experiments, this should be within the acceptable errors. The established LFERs are used to predict the HO(?) reaction rate constants within a factor of 5 from the experimental values. This approach may be applied to other reaction mechanisms to establish a library of rate constant predictions for kinetic modeling of AOPs. 相似文献
7.
A report on the experimental verification of the basic operation of the proposed type of integrated optical Y branch using Ti-diffused lithium niobate is presented. The advantages of this Y branch include low-branching loss, compact size, no need for extra bending or curved elements when used as a 3-dB coupler in M-Z type switches, and freedom from critical fabrication requirements. A branching loss of 0.5 dB is achieved. The necessary three-dimensional analysis of the Ti-diffused Y-branch structure is described 相似文献
8.
9.