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   134篇
  免费   7篇
电工技术   2篇
化学工业   54篇
金属工艺   3篇
机械仪表   2篇
建筑科学   7篇
矿业工程   1篇
能源动力   6篇
轻工业   22篇
水利工程   1篇
无线电   4篇
一般工业技术   22篇
冶金工业   4篇
原子能技术   1篇
自动化技术   12篇
  2024年   1篇
  2023年   3篇
  2022年   11篇
  2021年   15篇
  2020年   10篇
  2019年   15篇
  2018年   7篇
  2017年   8篇
  2016年   4篇
  2015年   11篇
  2014年   6篇
  2013年   19篇
  2012年   10篇
  2011年   5篇
  2010年   3篇
  2009年   3篇
  2008年   2篇
  2007年   1篇
  2004年   1篇
  2002年   1篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
排序方式: 共有141条查询结果,搜索用时 15 毫秒
41.
This paper presents a new negotiation model for designing Market- and Behavior-driven Negotiation Agents (MBDNAs) that address computational grid resource allocation problem. To determine the amount of concession for each trading cycle, the MBDNAs are guided by six factors: (1) number of negotiator's trading partners, (2) number of negotiator's competitors, (3) negotiator's time preference, (4) flexibility in negotiator's trading partner's proposal, (5) negotiator's proposal deviation from the average of its trading partners’ proposals, and (6) previous concession behavior of negotiator's trading partner. In our experiments, we compare grid resource consumer (GRC) of type MBDNAs (respectively grid resource owner (GRO) of type MBDNAs) with MDAs (Market Driven Agents) in terms of the following metrics: total tasks complementation and average utility (respectively resource utilization level and average utility). The results show that by taking the proposed factors into account, MBDNAs of both types make a more efficient concession amount than MDAs and are, therefore, considered an appropriate mechanism for grid resource allocation in different grid workloads and market types.  相似文献   
42.
43.

In this study, cerium oxide and multi-walled carbon nanotubes nanocomposite were incorporated into the carbon ceramic electrode (CeO2–MWCNTs/CCE) as a renewable electrode for the electrocatalytic purposes. To demonstrate capability of the fabricated electrode, determination of tamoxifen as an important anticancer drug with differential pulse voltammetry technique was evaluated in details. Linear range, limit of detection and sensitivity of the developed sensor were found to be 0.2–40 nM, 0.132 nM and 1.478 µA nM?1 cm?2, respectively. Ease of production, low cost and high electron transfer rate of the CeO2–MWCNTs/CCE promises it as a novel electro-analytical tool for determination of important species in real samples.

  相似文献   
44.
The potential of Mentha piperita in the iron nanoparticles (FeNPs) production was evaluated for the first time. The influences of the variables such as incubation time, temperature, and volume ratio of the extract to metal ions on the nanoparticle size were investigated using central composite design. The appearance of SPR bands at 284 nm in UV–Vis spectra of the mixtures verified the nanoparticle formation. Incubating the aqueous extract and metal precursor with 1.5 volume ratio at 50°C for 30 min leads to the formation of the smallest nanoparticles with the narrowest size distribution. At the optimal condition, the nanoparticles were found to be within the range of 35–50 nm. Experimental measurements of the average nanoparticle size were fitted well to the polynomial model satisfactory with R 2 of 0.9078. Among all model terms, the linear term of temperature, the quadratic terms of temperature, and mixing volume ratio have the significant effects on the nanoparticle average size. FeNPs produced at the optimal condition were characterised by transmission electron microscopy, thermogravimetry analysis (TGA), and Fourier‐transform infrared spectroscopy. The observed weight loss in the TGA curve confirms the encapsulation of FeNPs by the biomolecules of the extract which were dissociated by heat.Inspec keywords: thermal analysis, iron, X‐ray chemical analysis, particle size, nanoparticles, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, nanofabrication, ultraviolet spectra, mixtures, Fourier transform infrared spectraOther keywords: incubation time, metal ions, central composite design, SPR bands, UV–Vis spectra, nanoparticle formation, metal precursor, narrowest size distribution, optimal condition, average nanoparticle size, particle size, mixing volume ratio, green synthesis, zero‐valent iron nanoparticles, mentha piperita, transmission electron microscopy, thermogravimetry analysis, Fourier‐transform infrared spectroscopy, TGA curve, biomolecules, temperature 50.0 degC, time 30.0 min, size 35.0 nm to 50.0 nm, Fe  相似文献   
45.
Three-dimensional topological insulators (3D TI) exhibit conventional parabolic bulk bands and protected Dirac surface states. A thorough investigation of the different transport channels provided by the bulk and surface carriers using macroscopic samples may provide a path toward accessing superior surface transport properties. Bi2Te3 materials make promising 3D TI models; however, due to their complicated defect chemistry, these materials have a high number of charge carriers in the bulk that dominate the transport, even as nanograined structures. To partially control the bulk charge carrier density, herein the synthesis of Te-enriched Bi2Te3 nanoparticles is reported. The resulting nanoparticles are compacted into nanograined pellets of varying porosity to tailor the surface-to-volume ratio, thereby emphasizing the surface transport channels. The nanograined pellets are characterized by a combination of resistivity, Hall- and magneto-conductance measurements together with (THz) time-domain reflectivity measurements. Using the Hikami-Larkin-Nagaoka (HLN) model, a characteristic coherence length of ≈200 nm is reported that is considerably larger than the diameter of the nanograins. The different contributions from the bulk and surface carriers are disentangled by THz spectroscopy, thus emphasizing the dominant role of the surface carriers. The results strongly suggest that the surface transport carriers have overcome the hindrance imposed by nanoparticle boundaries.  相似文献   
46.
47.
Exacerbating the imbalance between demand for freshwater and available water resources is the sub-optimal performance of water distribution systems, which are plagued with leaks that cause significant losses of treated freshwater. This paper presents an approach for leak detection that involves continuous monitoring of the changes in the correlation between surface acceleration measured at discrete locations along the pipeline length. A metric called leak detection index is formulated based on cross-spectral density of measured pipe surface accelerations for detecting the onset and assessing the severity of leaks. The proposed non-invasive approach requires minimal human intervention and works under normal operating conditions of the pipeline system without causing any operational disturbances. The approach is demonstrated on a 76 mm diameter polyvinyl chloride pipeline test system considering varying leak severities. The preliminary results presented in this paper seem promising and lead to several interesting questions that will require further research.  相似文献   
48.
The development of a novel snack bar based on sesame paste (SP) and date syrup (DS) was investigated. The aim of this study was to evaluation the effects of SP/DS ratio and encapsulated thymol (thymol-loaded nanostructured lipid carrier [TNLC]) on physicochemical, textural, rheological, and sensorial properties of snack bars. The effect of butylated hydroxytoluene (BHT), thymol, and TNLC showed that the addition of 100 ppm TNLC could improve the oxidative stability of SP/DS mixtures even better than BHT, while a higher concentration of TNLC had a negative effect. The unpleasant taste and odor of thymol could be overcome by its encapsulation in nanostructured lipid carriers. The textural properties of the formulations with different SP/DS ratios (1:2, 1:1, 2:1) and an overall concentration of 7 g of gelatin/kg of mixtures were evaluated. The texture profile analysis showed that the sample with an SP/DS ratio of 1:1 had higher hardness, adhesiveness, springiness, cohesiveness, and gumminess in comparison with the other ratios. From the sensory evaluation data, the bar prepared with an SP/DS ratio of 1:1 had the most acceptable texture. According to the results, the SP/DS ratio of 1:1 with gelatin and 100 ppm TNLC can be used in developing SP/DS blends as a highly acceptable functional food.  相似文献   
49.
Bi2O3 compositions were prepared to investigate the effect of rare earth metal oxides as co-dopants on phase stability of bismuth oxide. Compositions containing 9-14 mol% of Y2O3 and Er2O3 were synthesized by solid state reaction. The structural characterization was carried out using X-ray powder diffraction. The XRD results show that the samples containing 12 and 14 mol% total dopants had cubic structure, whereas the samples with lower dopant concentrations were tetragonal. Comparing the lattice parameters of the cubic phases of (Bi2O3)0.88(Y2O3)0.06(Er2O3)0.06 and (Bi2O3)0.86(Y2O3)0.07(Er2O3)0.07 revealed that lattice parameter decreases by increasing the dopant concentration. The XRD pattern and the powder density results indicated the formation of solid solution in the studied systems. After annealing samples with cubic phase at 600 °C for various periods of time, phase transformation to tetragonal and rhombohedral occurs.  相似文献   
50.
Nanocapsules containing hexadecane (HD) as core material and polystyrene (PS) as shell, were electrospun with polyethylene oxide (PEO) as a matrix material into the fiber webs. The morphology and thermal properties of PEO fibers containing (1) both PS nanocapsules with core-shell morphology and solid PS particles, (2) only solid PS particles, and (3) without any PS particles, were compared and the effect of PEO concentration on morphology of the resultant fibers have been studied. The resultant fibers were characterized by means of Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). Both TEM observation and DSC analyses confirmed that the PS nanocapsules were encapsulated within the PEO nanofibers. The fibers had an average diameter of 950 nm for nanocapsules containing parts, 300 nm for solid particles containing parts, and 150 nm for usual parts. The phase change temperatures and phase transition heat of the produced fibers were determined by DSC analyses. TGA was also used to confirm the preparation of multi phase fibers and to determine the amount of HD within the fibers.  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