全文获取类型
收费全文 | 41篇 |
免费 | 2篇 |
专业分类
化学工业 | 4篇 |
金属工艺 | 2篇 |
能源动力 | 1篇 |
无线电 | 11篇 |
一般工业技术 | 16篇 |
冶金工业 | 7篇 |
自动化技术 | 2篇 |
出版年
2019年 | 2篇 |
2017年 | 4篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 6篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有43条查询结果,搜索用时 15 毫秒
21.
Calculation of diffuse scattering during h.c.p. to f.c.c. martensitic transition by non-random insertion of deformation faults using a Monte Carlo technique is presented. It is shown that a coherent modulation of wavelength λ = 6d111 can result during such transitions. The intensity and sharpness of the satellite peaks are shown to depend on the volume fraction of the twin-related f.c.c. variants. The predicted satellite peaks are in good agreement with those observed in Co and Co-Ni single crystals undergoing h.c.p. to f.c.c. martensitic transition. 相似文献
22.
23.
24.
Yana Vaynzof Thomas J. K. Brenner Dinesh Kabra Henning Sirringhaus Richard H. Friend 《Advanced functional materials》2012,22(11):2418-2424
This work investigates the composition and morphology of films of poly(3‐hexylthiophene) (P3HT), polyfluorene co‐polymer poly((9,9‐dioctylfluorene)‐2,7‐diyl‐alt‐[4,7‐bis(3‐hexylthien‐5‐yl)‐2,1,3‐benzothiadiazole]‐2′,2″‐diyl) (F8TBT) and blends thereof that are used in efficient all‐polymer solar cells. Ultraviolet photoemission spectroscopy (UPS) and X‐ray photoemission spectroscopy (XPS) studies on thin polymer and blend films on ZnO substrates reveal the existence of a 1–2 nm thick P3HT layer at the top surface of the blend films. XPS depth profiling studies reveal a density wave (λ ≈ 70 nm) originating from the air interface. As no preferential accumulation is observed at the bottom interface with ZnO, the composition at this interface is consistent with the original composition of the blend solution prior to spin‐coating. The morphology of this buried interface was studied by means of atomic force microscopy (AFM) and revealed that upon annealing the average domain size increases slightly (from 27 nm to 40 nm). It is observed that the photovoltaic performance of such inverted hybrid device improves upon annealing, however we believe this to mostly be a result of increased crystallinity in the P3HT domains leading to improved charge transport in the device, rather than changes in the blend phase separation. 相似文献
25.
Collective osmotic shock in ordered materials 总被引:1,自引:0,他引:1
Zavala-Rivera P Channon K Nguyen V Sivaniah E Kabra D Friend RH Nataraj SK Al-Muhtaseb SA Hexemer A Calvo ME Miguez H 《Nature materials》2012,11(1):53-57
Osmotic shock in a vesicle or cell is the stress build-up and subsequent rupture of the phospholipid membrane that occurs when a relatively high concentration of salt is unable to cross the membrane and instead an inflow of water alleviates the salt concentration gradient. This is a well-known failure mechanism for cells and vesicles (for example, hypotonic shock) and metal alloys (for example, hydrogen embrittlement). We propose the concept of collective osmotic shock, whereby a coordinated explosive fracture resulting from multiplexing the singular effects of osmotic shock at discrete sites within an ordered material results in regular bicontinuous structures. The concept is demonstrated here using self-assembled block copolymer micelles, yet it is applicable to organized heterogeneous materials where a minority component can be selectively degraded and solvated whilst ensconced in a matrix capable of plastic deformation. We discuss the application of these self-supported, perforated multilayer materials in photonics, nanofiltration and optoelectronics. 相似文献
26.
V. Bhatia D. Gupta D. Kabra K. S. Narayan 《Journal of Materials Science: Materials in Electronics》2007,18(9):925-930
Interface morphology play an important role in controlling transport characteristics for devices based on polymer semiconductors.
We modify the interface between the insulating surface and polymer film, poly(3-hexylthiophene) (P3HT), and control the interfacial
molecular ordering of the polymer film by using different self assembled molecules. We correlate the changes in the optical,
electrical transport, and photogenerated carrier transport to the functionalized surfaces that demonstrate different levels
of molecular ordering in the polymer film at the interface of insulating surface and polymer, ranging from a uniform-disordered
surface to lamella crystallite and highly oriented microdomains. 相似文献
27.
Myoung Hoon Song Dinesh Kabra Bernard Wenger Richard H. Friend Henry J. Snaith 《Advanced functional materials》2009,19(13):2130-2136
Here, the use of metal oxide layers both for charge transport and injection into an emissive semiconducting polymer and also for the control of the in‐plane waveguided optical modes in light‐emitting diodes (LEDs) is reported. The high refractive index of zinc oxide is used to confine these modes away from the absorbing electrodes, and include a nano‐imprinted grating in the polymer layer to introduce distributed feedback and enhance optical out‐coupling. These structures show a large increase in the luminescence efficiency over conventional devices, with photoluminescence efficiency increased by up to 45%. Furthermore, optically‐pumped lasing in hybrid oxide polymer LEDs is demonstrated. A tuneable lasing emission is also obtained in a single device structure by employing a graduated thickness of a zinc oxide inter‐layer. This demonstrates the scope for using such architectures to improve the external efficiency of organic semiconductor LEDs, and opens new possibilities for the realization of polymer injection lasers. 相似文献
28.
A numerical method is proposed for determining a discharge coefficient that relates mean velocity to the velocity measured
with an ultrasonic flowmeter.
Translated from Izmeritel'naya Tekhnika, No. 5, pp. 29–32, May, 1997. 相似文献
29.
Navin Kabra David J. DeWitt 《The VLDB Journal The International Journal on Very Large Data Bases》1999,8(1):55-78
In this paper we describe the design and implementation of OPT++, a tool for extensible database query optimization that
uses an object-oriented design to simplify the task of implementing, extending, and modifying an optimizer. Building an optimizer
using OPT++ makes it easy to extend the query algebra (to add new query algebra operators and physical implementation algorithms
to the system), easy to change the search space, and also to change the search strategy. Furthermore, OPT++ comes equipped
with a number of search strategies that are available for use by an optimizer-implementor. OPT++ considerably simplifies both,
the task of implementing an optimizer for a new database system, and the task of evaluating alternative optimization techniques
and strategies to decide what techniques are best suited for that database system. We present the results of a series of performance
studies. These results validate our design and show that, in spite of its flexibility, OPT++ can be used to build efficient
optimizers.
Received October 1996 / Accepted January 1998 相似文献
30.