首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   342篇
  免费   13篇
  国内免费   1篇
工业技术   356篇
  2023年   7篇
  2022年   26篇
  2021年   28篇
  2020年   34篇
  2019年   30篇
  2018年   30篇
  2017年   34篇
  2016年   33篇
  2015年   20篇
  2014年   15篇
  2013年   16篇
  2012年   8篇
  2011年   9篇
  2010年   8篇
  2009年   6篇
  2008年   5篇
  2007年   4篇
  2006年   5篇
  2005年   3篇
  2004年   5篇
  2003年   2篇
  2002年   1篇
  2000年   2篇
  1999年   3篇
  1998年   2篇
  1997年   2篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1990年   3篇
  1989年   2篇
  1988年   1篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
排序方式: 共有356条查询结果,搜索用时 0 毫秒
1.
In a large-scale locality-driven network such as in modular robotics and wireless sensor networks, knowing the state of a local area is sometimes necessary due to either interactions being local and driven by neighborhood proximity or the users being interested in the state of a certain region. We define locality-aware predicates (LAP) that aim at detecting a predicate within a specified area. We model the area of interest as the set of processes that are within a breadth-first search tree (BFST) of height kk rooted at the initiator process. Although a locality-aware predicate specifies a predicate only within a local area, observing the area consistently requires considering the entire system in a consistent manner. This raises the challenge of making the complexities of the corresponding predicate detection algorithms scale-free, i.e., independent of the size of the system. Since all existing algorithms for getting a consistent view of the system require either a global snapshot of the entire system or vector clocks of the size of the system, a new solution is needed. We focus on stable LAP, which are those LAP that remain true once they become true. We propose a scale-free algorithm to detect stable LAP within a kk-height BFST. Our algorithm can detect both stable conjunctive LAP and stable relational LAP. In the process of designing our algorithm, we also propose the first distributed algorithm for building a BFST within an area of interest in a graph, and the first distributed algorithm for recording a consistent sub-cut within the area of interest. This paper demonstrates that LAPs are a natural fit for detecting distributed properties in large-scale distributed systems, and stable LAPs can be practically detected at low cost.  相似文献   
2.
ABSTRACT

The state-of-the-art article presents concepts of nanobelt nanofiller, inimitable properties of derived polymeric nanocomposite, applications, and outlook on challenges to gain next generation high-performance materials. Nanobelt is a one-dimensional nanostructured nanomaterial. Owing to minuscule size and high surface area, nanobelt possesses unique structural, optical, electronic, mechanical, and thermal characteristics. Nanobelt exists in various forms such as carbon nanobelt, polymer nanobelt, and inorganic. These nanobelts have been used to develop polymer/nanobelt nanocomposites. Homogeneous dispersion of nanobelt in polymer matrices is desirable to enhance the characteristics of polymer/nanobelt nanocomposite. Consequently, innovations in design, fabrication, and properties of various polymer/nanobelt nanocomposite are summarized. Applications of polymer/nanobelt nanocomposite are reviewed for Li-ion battery, supercapacitor, sensor, membrane, and biomedical arenas.  相似文献   
3.
ABSTRACT

Fabrication of electronic materials from nanocomposite of biopolyesters reinforced with carbon nanotubes can be regarded as the effective alternative for conventional nanocomposites consisting of non-biodegradable polymers. Commercial availability of biopolyester-based nanocomposites is limited because of their high cost compared to other polymers, but the factor of their compostable nature is worthless for environmental protection. Such nanocomposites have potential applications in biodegradable sensors, EMI materials, etc. In this review, the current progress of biopolyester/CNTs nanocomposites in the field of biodegradable electronics is reviewed and also the impact of CNTs dispersion on electrical, thermal and mechanical properties of eco composites is stipulated.  相似文献   
4.
Journal of Central South University - This work is concerned with the analysis of blood flow through inclined catheterized arteries having a balloon (angioplasty) with time-variant overlapping...  相似文献   
5.
A novel image encryption algorithm in streaming mode is proposed which exhaustively employs an entire set of DNA complementary rules alongwith one dimensional chaotic maps. The proposed algorithm is highly efficient due to encrypting the subset of digital image which contains 92.125 % of information. DNA addition operation is carried out on this MSB part. The core idea of the proposed scheme is to scramble the whole image by means of piecewise linear chaotic map (PWLCM) followed by decomposition of image into most significant bits (MSB) and least significant bits (LSB). The logistic sequence is XORed with the decoded MSB and LSB parts separately and finally these two parts are combined to get the ciphered image. The parameters for PWLCM, logistic map and selection of different DNA rules for encoding and decoding of both parts of an image are derived from 128-bit MD5 hash of the plain image. Simulated experimental results in terms of quantitative and qualitative ways prove the encryption quality. Efficiency and robustness against different noises make the proposed cipher a good candidate for real time applications.  相似文献   
6.

In communication industry one of the most rapidly growing area is wireless technology and its applications. The efficient access to radio spectrum is a requirement to make this communication feasible for the users that are running multimedia applications and establishing real-time connections on an already overcrowded spectrum. In recent times cognitive radios (CR) are becoming the prime candidates for improved utilization of available spectrum. The unlicensed secondary users share the spectrum with primary licensed user in such manners that the interference at the primary user does not increase from a predefined threshold. In this paper, we propose an algorithm to address the power control problem for CR networks. The proposed solution models the wireless system with a non-cooperative game, in which each player maximize its utility in a competitive environment. The simulation results shows that the proposed algorithm improves the performance of the network in terms of high SINR and low power consumption.

  相似文献   
7.
Link relative-based approach was used in an article (see reference 1) to enhance the performance of the cumulative sum (CUSUM) control chart. This technique involves the use of firstly, the link relative variable to convert the process observations in a relative to the mean form and secondly, optimal constants to define a new variable which is used as the plotting statistic of the link relative CUSUM chart. In this article, it is proven through simulation study that the optimal constants with fixed values, as reported in the aforementioned article, give different results. Instead, if the regression technique is used, then the same results will be obtained.  相似文献   
8.
Multiple Sequences Alignment (MSA) of biological sequences is a fundamental problem in computational biology due to its critical significance in wide ranging applications including haplotype reconstruction, sequence homology, phylogenetic analysis, and prediction of evolutionary origins. The MSA problem is considered NP-hard and known heuristics for the problem do not scale well with increasing numbers of sequences. On the other hand, with the advent of a new breed of fast sequencing techniques it is now possible to generate thousands of sequences very quickly. For rapid sequence analysis, it is therefore desirable to develop fast MSA algorithms that scale well with an increase in the dataset size. In this paper, we present a novel domain decomposition based technique to solve the MSA problem on multiprocessing platforms. The domain decomposition based technique, in addition to yielding better quality, gives enormous advantages in terms of execution time and memory requirements. The proposed strategy allows one to decrease the time complexity of any known heuristic of O(N)xO(N)x complexity by a factor of O(1/p)xO(1/p)x, where NN is the number of sequences, xx depends on the underlying heuristic approach, and pp is the number of processing nodes. In particular, we propose a highly scalable algorithm, Sample-Align-D, for aligning biological sequences using Muscle system as the underlying heuristic. The proposed algorithm has been implemented on a cluster of workstations using the MPI library. Experimental results for different problem sizes are analyzed in terms of quality of alignment, execution time and speed-up.  相似文献   
9.
The oxidative stability and compositional characteristics of the pumpkin seed oil (PSO) exposed to microwaves were studied during heating at 170°C. The oxidative indices such as free fatty acid (FFA), peroxide value (PV), p-anisidine value (p-AV), TOTOX, specific extinctions and thiobarbituric acid (TBA) value of oils were significantly increased, and the increments were found to be significantly higher (P < 0.05) in unroasted seed oil as compared to roasted seed oil. The relative contents of polyunsaturated fatty acids (PUFAs) were decreased to 84.7%, and saturated fatty acids (SFAs) were increased to 119.5% in unroasted sample, after 9 h of heating. On the other hand, in 12 min roasted samples, the relative contents of PUFAs were decreased to 97.0%, and SFAs were increased to 102.6% after 9 h of heating. The triacylglycerol species LLL and OLL levels were decreased as a consequence of increased heating time, and the reduction tended to be significantly higher in unroasted samples as compared to roasted ones. The oxidation products formed were also investigated by FTIR. The present results indicated that microwave roasting of pumpkin seeds markedly enhanced the oxidative stability of the oils during heating.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号