全文获取类型
收费全文 | 165篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 33篇 |
金属工艺 | 8篇 |
机械仪表 | 6篇 |
建筑科学 | 4篇 |
能源动力 | 4篇 |
轻工业 | 6篇 |
无线电 | 44篇 |
一般工业技术 | 42篇 |
冶金工业 | 4篇 |
原子能技术 | 2篇 |
自动化技术 | 14篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 8篇 |
2012年 | 9篇 |
2011年 | 14篇 |
2010年 | 8篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 10篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1987年 | 1篇 |
排序方式: 共有169条查询结果,搜索用时 218 毫秒
161.
Synthesis and thermoelectric characterization of bulk-type tellurium nanowire/polymer nanocomposites
Seil Kim Young-In Lee Seung Han Ryu Tae-Yeon Hwang Yoseb Song Sungho Seo Bongyoung Yoo Jae-Hong Lim Hong-Baek Cho Nosang V. Myung Yong-Ho Choa 《Journal of Materials Science》2017,52(21):12724-12733
A simple method to fabricate three-dimensionally (3-D) aligned thermoelectric nanowires attached polymer particle was demonstrated by combination of solution casting of thermoelectric nanostructures (e.g., tellurium nanowires (Te NWs)) on the surface of thermoplastic polymer (e.g., poly(methyl methacrylate (PMMA)) microbeads followed by hot compaction of thermoplastic matrix. The percolation threshold of composite with 3-D assembled Te NWs (i.e., 3.45 vol%) significantly was lower than that of a randomly dispersed Te NWs (i.e., 5.26 vol%), which resulted in an order of magnitude greater thermoelectric figure of merit (ZT of 2.8 × 10?3) compared to randomly dispersed Te NWs in PMMA matrix (ZT of 6.4 × 10?4) at room temperature by enhancing the electrical conductivity without increasing thermal conductivity. 相似文献
162.
We report in this paper the architectural design and implementation of all-optical packet networks. Using photonic switches to route information, an all-optical network has the advantages of bit rate, wavelength, and signal format transparencies. Within the transparency distance, the network is capable of handling a widely heterogeneous mix of traffic. We will describe our research on the implementation of all-optical backbone switches. The switch components including frame synchronizers, frame delineation units, frame header over-writing units, wavelength converters, frame concentrators, and WDM buffers were constructed at 2.5 Gb/s. Their subsystem and device structure as well as preliminary performance are reported. 相似文献
163.
Recent use of magnetoresistive (MR)/giant-magnetoresistive (GMR) heads in disk drives requires tighter control on particle contamination that may generate thermal asperities at the head/disk interface. In this study, the effects of slider air bearing surface (ABS) design and media on TA reduction capability are investigated. The motion of particles at the head/media interface is simulated numerically. Drive level TA tests are performed using a particle injection chamber. It is observed that a new ABS design, that has an aerodynamic U-shaped rail and a central airflow passage, is beneficial in reducing the particle contamination on the slider. Scratch-resistance of the media surface is correlated to TA reduction capability of the media; more scratch-resistant media produced less TA. On the other hand, the adhesion properties of the media have minor effects on TA reduction, as the particles that usually generate TA in a drive are too small to spin off the media. 相似文献
164.
Chao H.J. Wu L. Zhang Z. Yang S.H. Wang L.M. Chai Y. Fan J.Y. Choa F.S. 《Lightwave Technology, Journal of》2000,18(3):273-285
Dense wavelength-division multiplexing (DWDM) technology has provided tremendous transmission capacity in optical fiber communications. However, switching and routing capacity is still far behind transmission capacity. This is because most of today's packet switches and routers are implemented using electronic technologies. Optical packet switches are the potential candidate to boost switching capacity to be comparable with transmission capacity. In this paper, we present a photonic asynchronous transfer mode (ATM) front-end processor that has been implemented and is to be used in an optically transparent WDM ATM multicast (3M) switch. We have successfully demonstrate the front-end processor in two different experiments. One performs cell delineation based on ITU standards and overwrites VCI/VPI optically at 2.5 Gb/s. The other performs cell synchronization, where cells from different input ports running at 2.5 Gb/s are phase-aligned in the optical domain before they are routed in the switch fabric. The resolution of alignment is achieved to the extent of 100 ps (or 1/4 bit). An integrated 1×2 Y-junction semiconductor optical amplifier (SOA) switch has been developed to facilitate the cell synchronizer 相似文献
165.
We prepared a series of aromatic liquid crystals (LCs) based on aromatic ester units with the reactive end groups methyl-maleimide and nadimide, and the resulting LCs were thermally cross-linked to produce liquid crystalline thermoset (LCT) films by means of solution-casting and heat treatment. The synthesized LCs and LCTs were characterized with Fourier transform infrared (FT-IR) spectroscopy, 1H nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and polarizing optical microscopy with a hot stage. We found that all these LCs form nematic phases. The coefficients of thermal expansion (CTEs) of the LCT films are strongly affected by the reactive end group and the mesogen units in their main-chain structures. The methyl-maleimide-terminated biphenyl LCT was found to have the lowest CTE. 相似文献
166.
Young-In LeeYong-Sung Goo Kun-Jae LeeYun-Gu Hwang Younghun ByunHee Jung Park Deok-Yong ParkNosang V. Myung Yong-Ho Choa 《Thin solid films》2011,519(20):6853-6857
In this study, we apply UV/ozone treatment to modify the surface properties of polyimide substrate and investigate the effects of UV/ozone treatment on surface properties of polyimide and the morphologies of ink-jet printed Cu patterns. Wettability of polyimide surface is enhanced by UV/ozone treatment as confirmed by contact angle analysis and XPS results. The change in wettability affected droplet sizes and morphologies of ink-jet-printed lines. The average droplet size increased from 26.8 μm on untreated polyimide to 42.5 μm after UV/ozone treatment. Furthermore, irregular patterns of coexisting beads and short lines were observed in untreated polyimide film, despite minimal overlap of dots. In contrast, patterns that were ink-jet printed on polyimide film that was modified by UV/ozone for 1 h showed continuous lines with straight edges. 相似文献
167.
Lee YI Goo YS Chang CH Lee KJ Myung NV Choa YH 《Journal of nanoscience and nanotechnology》2011,11(2):1455-1458
Polycrystalline copper oxide nanostructures with different valence/oxidation states (i.e., Cu2O and CuO) were readily synthesized by thermal oxidation of single crystalline copper nanowires at relative low operating temperature (200 to 300 degrees C). Operating temperature of 200 to 250 degrees C in air oxidized copper to Cu2O and further increased temperature (i.e., 300 degrees C) led to form CuO nanostructures. The morphology of nanostructures significantly altered from nanowires to nanotubes which might be attributed to Kirkendall effect. The electrical resistivity of single copper nanowire, Cu2O and CuO nanotube were determined to be 3.4 x 10(-4), 33, and 211 omega cm, respectively. 相似文献
168.
Jang DH Song H Lee YI Lee KJ Kim KH Oh ST Lee SK Choa YH 《Journal of nanoscience and nanotechnology》2011,11(1):763-767
Recently, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become serious problems due to the growth of electronic device and next generation telecommunication. It is necessary to develop new electromagnetic wave absorbing material to overcome the limitation of electromagnetic wave shielding materials. The EMI attenuation is normally related to magnetic loss and dielectric loss. Therefore, magnetic material coating dielectric materials are required in this reason. In this study, TiO2 coated Fe nanofibers were prepared to improve their properties for electromagnetic wave absorption. Poly(vinylpyrrolidone) (PVP) and Iron (III) nitrate nonahydrate (Fe(NO3)3 x 9H2O) were used as starting materials for the synthesis of Fe oxide nanofibers. Fe oxide nanofibers were prepared by electrospinning in an electric field and heat treatment. TiO2 layer was coated on the surface of Fe oxide nanofibers using sol-gel process. After the reduction of TiO2 coated Fe oxide nanofibers, Fe nanofibers with a TiO2 coating layer of about 10 nm were successfully obtained. The morphology and structure of fibers were characterized by SEM, TEM, and XRD. In addition, the absorption properties of TiO2 coated Fe nanofibers were measured by network analyzer. 相似文献
169.