全文获取类型
收费全文 | 250篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 29篇 |
金属工艺 | 9篇 |
机械仪表 | 5篇 |
建筑科学 | 2篇 |
能源动力 | 17篇 |
轻工业 | 5篇 |
无线电 | 37篇 |
一般工业技术 | 46篇 |
冶金工业 | 27篇 |
原子能技术 | 4篇 |
自动化技术 | 75篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 7篇 |
2012年 | 10篇 |
2011年 | 4篇 |
2010年 | 15篇 |
2009年 | 13篇 |
2008年 | 7篇 |
2007年 | 21篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有257条查询结果,搜索用时 15 毫秒
1.
A study of the energy consumption characteristics of cryptographic algorithms and security protocols 总被引:2,自引:0,他引:2
Potlapally N.R. Ravi S. Raghunathan A. Jha N.K. 《Mobile Computing, IEEE Transactions on》2006,5(2):128-143
Security is becoming an everyday concern for a wide range of electronic systems that manipulate, communicate, and store sensitive data. An important and emerging category of such electronic systems are battery-powered mobile appliances, such as personal digital assistants (PDAs) and cell phones, which are severely constrained in the resources they possess, namely, processor, battery, and memory. This work focuses on one important constraint of such devices-battery life-and examines how it is impacted by the use of various security mechanisms. In this paper, we first present a comprehensive analysis of the energy requirements of a wide range of cryptographic algorithms that form the building blocks of security mechanisms such as security protocols. We then study the energy consumption requirements of the most popular transport-layer security protocol: Secure Sockets Layer (SSL). We investigate the impact of various parameters at the protocol level (such as cipher suites, authentication mechanisms, and transaction sizes, etc.) and the cryptographic algorithm level (cipher modes, strength) on the overall energy consumption for secure data transactions. To our knowledge, this is the first comprehensive analysis of the energy requirements of SSL. For our studies, we have developed a measurement-based experimental testbed that consists of an iPAQ PDA connected to a wireless local area network (LAN) and running Linux, a PC-based data acquisition system for real-time current measurement, the OpenSSL implementation of the SSL protocol, and parameterizable SSL client and server test programs. Based on our results, we also discuss various opportunities for realizing energy-efficient implementations of security protocols. We believe such investigations to be an important first step toward addressing the challenges of energy-efficient security for battery-constrained systems. 相似文献
2.
The behavior and suitability of cold-formed lipped angle members for X-bracing with redundant have been studied. For the purpose, two full-scale panel tests were carried out. The first panel was designed so that the compression member would fail by buckling in flexural mode and the second panel in flexural-torsional mode. The members were designed using ASCE Manual No. 52. Theoretical aspects of least radius of gyration and buckling behavior of this bracing system have been discussed. The investigation on first panel, revealed that the member would buckle only in the flexural-torsional mode although flexural buckling would govern the design. The second panel test result showed that, the buckling mode and strength of the system for lipped angle sections can be predicted reasonably well. 相似文献
3.
P. Kuppusami V. S. Raghunathan A. G. Vedheswar 《Journal of Materials Science: Materials in Electronics》1996,7(3):207-212
A two-step fabrication process for the creation of a bi-epitaxial junction in thin films of YBa2Cu3O7 – x
is described. The junction has been fabricated on (100) SrTiO3 substrate using a buffer layer of CeO2. Polarized light optical microscopy indicates a regular basket-weave microstructure and a granular structure on either side of the junction. The junction shows Josephson critical currents at temperatures upto 74 K and the critical current increases linearly with decreasing temperature. 相似文献
4.
Characteristics of 4H-SiC Schottky barrier diodes with breakdown voltages up to 1000 V are reported for the first time. The diodes showed excellent forward I-V characteristics, with a forward voltage drop of 1.06 V at an on-state current density of 100 A/cm2. The specific on-resistance for these diodes was found to be low (2×10 -3 Ω-cm2 at room temperature) and showed a T 1.6 variation with temperature. Titanium Schottky barrier height was determined to be 0.99 eV independent of the temperature. The breakdown voltage of the diodes was found to decrease with temperature 相似文献
5.
A. D. Raidoo K.S.M.S. Raghav Rao S. B. Sawant J. B. Joshi 《Chemical Engineering Communications》1987,54(1):241-264
Rate of gas induction, static pressure, mixing time and power consumption have been measured in 0.57 m i.d. vessel. Different types of impellers namely shrouded disc turbine, shrouded curved blade turbine and pitched blade turbine were used. The impeller diameter was varied from 0.15-0.25 m and the impeller speed was varied from 3 to 20 r/s.
The pitched blade turbine was found to give 30-60 per cent higher rates of gas induction as compared with the best design reported in the literature. The mixing time was found to be lower by a similar magnitude. Moreover in the case of pitched blade turbine it was found that the gas was getting induced radially as well as axially. This eliminates the necessity of the diffuser and hence reducing the complexities in the mechanical structure. 相似文献
The pitched blade turbine was found to give 30-60 per cent higher rates of gas induction as compared with the best design reported in the literature. The mixing time was found to be lower by a similar magnitude. Moreover in the case of pitched blade turbine it was found that the gas was getting induced radially as well as axially. This eliminates the necessity of the diffuser and hence reducing the complexities in the mechanical structure. 相似文献
6.
Alok Singh Sitaram Dash Mohammed Kamruddin Puthupparampil K. Ajikumar Ashok K. Tyagi Vinjamoor S. Raghunathan Baldev Raj 《Journal of the American Ceramic Society》2002,85(4):927-932
Formation of nanocrystalline calcia from calcite has been studied in situ via transmission electron microscopy. The crystallographic transformation occurred via two mechanisms: the first is by distortion of the cleaved rhombohedron of calcite, formed by {104} planes in hexagonal coordinates, into a cube. This produced a microstructure of oriented, elongated nanocrystals of calcia with planar boundaries. In the second mechanism, the micrometer-sized parent calcite particles broke up into nano-sized grains as the decomposition began, leading to irregularly shaped, randomly oriented nanocrystals of calcia. 相似文献
7.
Raghav V. Sampangi Srinivas Sampalli 《International Journal of Information Security》2017,16(4):417-433
Cryptographic algorithms rely on the strengths of all their fundamental components and expect them to be harmonious in accomplishing desired levels of security in applications. In order for a security solution to be sophisticated and to provide high security (measured in terms of the security goals it satisfies), the solution needs to typically involve complex mathematical operations and/or multiple stages of operation. While these might offer increased security, such solutions might not be applicable to all systems. We refer to resource-constrained wireless networks, such as radio frequency identification and wireless body area networks, where the resources available on-chip are often decided by the balance between device costs, requirements of longevity and usability. The constraints, thus, require designing solutions that use simple logical operations and are based on reuse of functions, while introducing sufficient unpredictability to increase security. In this paper, we present a key management and message signature generation scheme called HiveSec, whose design is inspired by the symmetry in beehives and the nature of bee swarms, and which offers security through unpredictability and reduced resource usage. We validate our work through simulation studies and security analysis. 相似文献
8.
Probabilistic belief contraction has been a much neglected topic in the field of probabilistic reasoning. This is due to the difficulty in establishing a reasonable reversal of the effect of Bayesian conditionalization on a probabilistic distribution. We show that indifferent contraction, a solution proposed by Ramer to this problem through a judicious use of the principle of maximum entropy, is a probabilistic version of a full meet contraction. We then propose variations of indifferent contraction, using both the Shannon entropy measure as well as the Hartley entropy measure, with an aim to avoid excessive loss of beliefs that full meet contraction entails. 相似文献
9.
R. Mythili V. Thomas Paul S. Saroja M. Vijayalakshmi V.S. Raghunathan 《Materials Science and Engineering: A》2005,390(1-2):299-312
An alloy of composition Ti–4.4 wt.% Ta–1.9 wt.% Nb is being developed as a structural material for corrosion applications, as titanium and its alloys possess excellent corrosion resistance in many oxidizing media. The primary physical metallurgy database for the Ti–4.4 wt.% Ta–1.9 wt.% Nb alloy is being presented for the first time. Determination of the β transus, Ms temperature and classification of the alloy have been carried out, employing a variety of microscopy techniques, X-ray diffraction (XRD), micro-hardness and differential scanning calorimetry (DSC). The β transition temperature or β transus determined using different experimental techniques was found to agree very well with evaluations based on empirical calculations. Based on chemistry and observed room temperature microstructure, the alloy has been classified as an + β titanium alloy. The high temperature β transforms to either ′ or + β by a martensitic or Widmanstatten transformation. The mechanisms of transformation of β under different conditions and characteristics of different types of have been studied and discussed in this paper. 相似文献
10.
Manoj Gaur Jaya Lohani R. Raman V.R. Balakrishnan P. Raghunathan S.V. Eswaran 《Synthetic Metals》2010,160(19-20):2061-2064
Diode devices (glass/ITO/polymer/Al) have been fabricated using poly (3-hexylthiophene) (P3HT) crosslinked with two different biaryl crosslinkers. Crosslinking was performed by exposing the thin films with different wt% of crosslinker to UV irradiation and progress of crosslinking was monitored by IR spectroscopy. An increase in hole mobility of two orders of magnitude has been observed after crosslinking. 相似文献