首页 | 本学科首页   官方微博 | 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   78篇
  免费   3篇
  国内免费   4篇
电工技术   1篇
化学工业   5篇
金属工艺   2篇
能源动力   6篇
轻工业   6篇
无线电   31篇
一般工业技术   22篇
冶金工业   3篇
原子能技术   3篇
自动化技术   6篇
  2023年   1篇
  2022年   1篇
  2018年   1篇
  2017年   2篇
  2016年   2篇
  2015年   1篇
  2014年   3篇
  2013年   3篇
  2012年   2篇
  2011年   4篇
  2010年   5篇
  2009年   6篇
  2007年   2篇
  2006年   2篇
  2005年   2篇
  2004年   3篇
  2003年   1篇
  2002年   3篇
  2001年   1篇
  2000年   2篇
  1999年   2篇
  1998年   1篇
  1997年   2篇
  1996年   4篇
  1995年   2篇
  1994年   5篇
  1993年   3篇
  1992年   2篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
  1974年   1篇
  1971年   1篇
  1964年   1篇
  1963年   1篇
排序方式: 共有85条查询结果,搜索用时 15 毫秒
1.
A RKHS interpolator-based graph matching algorithm   总被引:1,自引:0,他引:1  
We present an algorithm for performing attributed graph matching. This algorithm is derived from a generalized framework for describing functionally expanded interpolators which is based on the theory of reproducing kernel Hilbert spaces (RKHS). The algorithm incorporates a general approach to a wide class of graph matching problems based on attributed graphs, allowing the structure of the graphs to be based on multiple sets of attributes. No assumption is made about the adjacency structure of the graphs to be matched  相似文献   
2.
The Journal of Supercomputing - Smart services are a concept that provides services to the citizens in an efficient manner. The online shopping and recommender system can play an important role for...  相似文献   
3.
This letter presents an analytical model for evaluating the bit error rate (BER) of a direct sequence code division multiple access (DS-CDMA) system, with M-ary orthogonal modulation and noncoherent detection, employing an array antenna operating in a Nakagami fading environment. An expression of the signal to interference plus noise ratio (SINR) at the output of the receiver is derived, which allows the BER to be evaluated using a closed form expression. The analytical model is validated by comparing the obtained results with simulation results.  相似文献   
4.
Nickel hydroxide nanosheets, nanobelts and nanorods were prepared by hydrothermal treatment of the precipitates obtained at different pH values. The morphology and crystal structure of the products could be controlled simply by adjusting the pH value at precipitation. Interconnected nanosheets of hexagonal β-Ni(OH)2 with thickness around 10–20 nm were formed at pH ∼ 11, whereas nanobelts with typical widths around 40–80 nm, and nanorods with diameters around 50–60 nm of phase pure α-Ni(OH)2 containing intercalated sulphate ions were obtained in the pH range ∼9.5–8.5. Thermal annealing of the hydroxides at 500 °C yielded cubic phase NiO with morphologies similar to their hydroxide precursors. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX) analysis were used to characterize the as-prepared products. The role of pH in controlling the phase and morphology of the products was discussed.  相似文献   
5.
Traditional refined track initiation methods for group targets have mistakes or loss of tracks when tracking irregular motions, for the reason that they rely on a stable relative position of group members. To solve the problem, a group dynamic model was introduced for proposing a new initiation algorithm and its whole framework. We made a self-adaptive improvement of the group separation on various group radii. After the pre-association of these groups, a state equation derived from the model was used for predictions of group members. Then a relational matrix was defined for refined data associations. Finally tracks were validated by logic-based method. Particular scenarios and Monte Carlo simulations showed that, compared with algorithms based on relative position, this algorithm has better performance on the adaptability to changes of a group structure and the correctness of initiation.  相似文献   
6.
This paper addresses the influence that the sampling locations have on the estimated frequencies of superimposed sinusoids. This problem has application in harmonic time-series analysis or direction-finding phased-array systems. Generalized mathematical bounds are developed in terms that are independent of the array locations and have an intuitively appealing physical interpretation. They establish the influence of the sampling locations on the variance of the frequency estimate and the limit at which two sources can be resolved using signal subspace estimators. For the resolution criteria, an expression dominated by the fourth central moment of the sensor locations expresses the resolving ability of the sensing array, irrespective of the array aperture or number of sensors. Increasing the fourth central moment increases an array's resolution ability. The commonly accepted notion that resolution necessarily depends on the array aperture is misleading and, indeed, that fewer snapshots from a reduced aperture array can outperform a larger array of more elements. For the estimator variance criteria, it is found that the product of the number of sensors and the second central moment (array variance) characterizes the estimator variance lower bound. The metrics developed demonstrate that the sampling topology is itself an important factor in determining the performance of the sampling system (and not the covariance lags sampled or the aperture spanned). Simulations are used to describe the results  相似文献   
7.
Effect of irradiation treatment (0.5, 1.0, 2.0 and 4.0 kGy) on fresh pea cultivars was investigated. Results indicated that significant decrease in colour (% transmittance) and ascorbic acid occurred due to storage period. Higher irradiation treatments showed a significant difference in colour retention in both the cultivars. Visual observation indicated no sprouting until 6th days after which sprouting started in both the cultivars irrespective of radiation treatments. At higher irradiation dose (4.00 kGy) sprouts died soon after emergence. Peas irradiated at 2.0-4.0 kGy doses showed rottage after 9-12 days of storage in both the varieties. Higher irradiation doses enhanced the rate of rot compared with lower doses, p-8 was more resistant to rottage than Moon cultivar of pea.  相似文献   
8.
Some results are presented on the convergence rate of lattice filters when adaptive algorithms are employed for estimating their reflection coefficients. It is shown that, unlike tapped-delay-line filters, adaptive lattices are not affected by ill-conditioned data.  相似文献   
9.
A new design method for all-pole infinite impulse response (i.i.r.) digital filters is introduced. The method involves minimising the area between the ideal lowpass filter response in the passhand and the actual passband response, subject to a quadratic constraint which ensures filter realisability. A unique solution is obtained to the minimisation which relates the filter weights to the eigenvector of a Toeplitz matrix. The filters are seen to have a small ripple in the passhand and a sharp cutoff in the stopband.  相似文献   
10.
Highly pure n-3 polyunsaturated fatty acids (PUFA)-enriched triacylglycerols (TAG) have attracted considerable attention due to their nutritional benefits and pharmacological effects. In this study, an alternative approach to the conventional method for the synthesis of highly pure n-3 PUFA-enriched TAG by using a multi-step process was reported. First, glyceride mixtures were synthesized through Novozym 435 [Novozymes A/S (Bagsvaerd, Denmark)] catalyzed esterification of n-3 PUFA-enriched FA and glycerol. Second, partial glycerides in the resulting glyceride mixtures were hydrolyzed to FA by immobilized partial glycerides-selective lipase from Malassezia globosa. The purity of TAG reached 99.84% under the optimized conditions: buffer solution of pH 6.0, water content of 100% (w/w, with respect to the oil mass), enzyme loading of 120 U/g (U/w, with respect to oil mass) and reaction temperature of 30 °C. During hydrolysis, the immobilized SMG1-F278N exhibited good reusability and TAG purity of over 94% was maintained after being used for six cycles. Subsequently, purification of TAG was accomplished by molecular distillation at low temperature (150 °C) and highly pure (99.85%) TAG with 88.73% n-3 PUFA was obtained. The final glyceride mixtures with low acid, peroxide and anisidine value were promising products for medical and dietetic purposes. Compared with the conventional one-step synthesis of n-3 PUFA-enriched TAG by enzymatic esterification or glycerolysis or the two-step method by combined transesterification and ethanolysis, this improved process allows for higher purity of n-3 PUFA-enriched TAG and significant reduction in reaction time.  相似文献   
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