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   72篇
  免费   8篇
电工技术   3篇
综合类   2篇
化学工业   10篇
金属工艺   1篇
建筑科学   1篇
能源动力   2篇
轻工业   4篇
石油天然气   10篇
无线电   13篇
一般工业技术   15篇
冶金工业   7篇
自动化技术   12篇
  2024年   1篇
  2022年   2篇
  2021年   2篇
  2020年   2篇
  2019年   6篇
  2018年   6篇
  2017年   1篇
  2016年   6篇
  2015年   4篇
  2014年   3篇
  2013年   10篇
  2012年   4篇
  2011年   4篇
  2010年   2篇
  2009年   2篇
  2008年   2篇
  2006年   1篇
  2003年   1篇
  2002年   1篇
  2000年   1篇
  1999年   2篇
  1998年   4篇
  1997年   5篇
  1996年   2篇
  1994年   2篇
  1991年   1篇
  1988年   2篇
  1968年   1篇
排序方式: 共有80条查询结果,搜索用时 172 毫秒
1.
一种基于数据流跟踪的无线传感网能量模型及网络优化   总被引:2,自引:1,他引:1  
提出了一种基于数据流跟踪的能量模型,通过跟踪数据流在网络中的整个过程来计算全网的能量消耗,是一种不受网络结构限制的普遍适用的能量模型;在此基础上.建立了基于能耗的网络优化模型,针对链式和簇式结构进行了拓扑、功率和路由方面的优化设计,仿真结果证明了理论分析的正确性.  相似文献   
2.
In an asymmetric rendezvous system, such as an unfair synchronous queue or an elimination array, threads of two types, consumers and producers, show up and are matched each with a unique thread of the other type. Here we present new highly scalable, high throughput asymmetric rendezvous systems that outperform prior synchronous queue and elimination array implementations under both symmetric and asymmetric workloads (more operations of one type than the other). Based on this rendezvous system, we also construct a highly scalable and competitive stack implementation.  相似文献   
3.
Effective direct removal of actinides such as Pu and Am from bone in vivo has not been accomplished to date, even with the strong chelating agents CaNa3DTPA or ZnNa3DTPA. This study, using an established in vitro system, compared removal of Pu and Am bound to bone mineral by ZnNa3DTPA and 10 chelating agents designed specifically to sequester actinides, including Pu and Am. Ligands tested were tetra, hexa, and octadentate, with linear or branched backbones containing sulfocatechol [CAM(S)], hydroxycatechol [CAM(C)], hydroxipyridinone (1,2-HOPO, Me-3,2-HOPO), or hydroxamate functional groups. The wide range of Pu and Am removal exhibited by the test ligands generally agreed with their metal coordination and chemical properties. The most effective agents for Pu (100 microM concentration, 24-48 h contact) are all octadentate as follows: 3,4,3-LICAM(S) (54% unbound); 3,4,3-LICAM(C) (6.2%); 3,4,3-LI(1,2-HOPO) (3.8%); H(2,2)-(Me-3,2-HOPO) (2.2%) and DFO-(1,2-HOPO) (1.8%). The other ligands removed less than 1% of the bound Pu; and ZnNa3DTPA removed only 0.086%. The most effective ligands for Am removal (100 microM, 24-48 h contact) are as follows: octadentate H(2,2)-(Me-3,2-HOPO) (21% unbound); 3,4,3-LI(1,2-HOPO) (14.5%) and 3,4,3-LICAM(C) (5.9%); hexadentate TREN-(Me-3,2-HOPO) and TREN-(1,2-HOPO) (9.6%); and tetradentate 5-LIO(Me-3,2-HOPO) (5.2%). Am removal by ZnNa3DTPA was about 1.4%. Among the ligands presently considered for possible human use, only 3,4,3-LI(1,2-HOPO) removed potentially useful amounts of both Pu and Am from bone mineral.  相似文献   
4.
ABSTRACT

Distributed parameter drying models such as the Fick's law diffusion model, unlike the lumped parameter model of van Meel whose parameters can be easily estimated by regression, suffer from the difficulty in estimating the parameters of the models quantitatively with accuracy. In the past they were estimated by visual inspection of the theoretical drying curves which fit the experimental drying curve best In this work, a quantitative parameter estimation technique originally suggested by Chavent, is developed by minimizing the integrated squares of error between theoretical and experimental curves over the drying lime (the criterion) subjected to the constraints that the theoretical curve is governed by the constant diffusivity Fick's taw diffusion equation (the constraint). Although the estimation of Fick's law constant diffusivity can be done by using the analytical solution developed by Crank, the use of the Fick's law model here is simply to demonstrate the utility of the proposed technique which can be used in more complex distributed models. The optimization problem is to solve for the adjoint equation for which the value of the Fick's law diffusivity minimizes the criterion. The Lagrangian derivative is solved by using a discrete derivative of the criterion. The theoretical curves are generated by using simple explicit (FSE) and modified Crank-Nicholson (FCR) algorithms The drying of oil palm kernels are used as a case study. Ii is found that the estimated diffusivities of moisture in oil palm kernels range from 0 5 to 5.0 × 10-10 m2sol;s which are comparable with published data. It is also found that the estimated diffusivity is dependent on the initial moisture content.  相似文献   
5.
Candlenut oil was extracted using supercritical CO(2) (SC-CO(2)) with an optimization of parameters, by the response surface methodology. The ground candlenut samples were treated in 2 different ways, that is, dried in either a heat oven (sample moisture content of 2.91%) or dried in a vacuum oven (sample moisture content of 1.98%), before extraction. An untreated sample (moisture content of 4.87%) was used as a control. The maximum percentage of oil was extracted from the heat-oven-dried sample (77.27%), followed by the vacuum-oven-dried sample (74.32%), and the untreated sample (70.12%). At an SC-CO(2) pressure of 48.26 Mpa and 60 min of extraction time, the optimal temperatures for extraction were found to be 76.4 °C, 73.9 °C, and 70.6 °C for the untreated, heat-oven-dried, and vacuum-oven-dried samples, respectively. The heat-oven-dried sample contains the highest percentage of linoleic acid, followed by the untreated and vacuum-oven-dried samples. The antiradical activity of candlenut oil corresponded to an IC(50) value of 30.37 mg/mL.  相似文献   
6.
The Upper Triassic Baluti Formation has been identified and mapped based on its log response in selected wells from the Zagros foldbelt in the Kurdistan Region of northern Iraq. A preliminary evaluation of the formation's source rock potential was made by Rock-Eval screening analysis in four wells along a NW-SE profile (Atrush-1, Shaikan-5B, Taq Taq-22 and Miran-2) with maturity determined from reflectance measurements in samples from well Taq Taq-22. The Baluti Formation consists of thinly interbedded shales, carbonates and anhydrite ranging in thickness from 48 m in well Atrush-1 to 118 m in well Miran-2. The Rock-Eval screening was conducted primarily on bulk cuttings samples plus selected picked cuttings. The TOC content is low to moderate (0.23 to 1.14 wt%). However, the shale content in many of the analysed bulk samples was relatively low, making assessment of the source potential problematic. The highest TOCs are recorded from the thickest analysed sections from wells Miran-2 and Taq Taq-22, where high-gamma bituminous shales are present. Rock-Eval Tmax values ranging from 295 to 438°C are not consistent with estimates of pre-Zagros burial to depths of between 4600 m (Atrush-1) and 6900 m (Miran-2). The relatively low Tmax values suggest that the S2 response does not reflect kerogen pyrolysis in these samples and may be due to the presence of solid bitumen, which is observed in the Baluti Formation in at least three of the study wells (Taq Taq-22, Miran-2 and Shaikan-5B). Little pyrolysable organic matter remains in the formation due to the interpreted deep pre-Zagros burial and the consequent high maturity in Taq Taq-22 (VR = 1.51%Ro) and Miran-2 (estimated VR >2%Ro), and the poor source character in Atrush-1 and Shaikan-5B. Organic petrography suggests the presence of vestiges of Types I and II kerogen in Taq Taq-22, with bitumen observed as stains in the matrix of the shales and also in the pores and fractures of interbedded dolostones. However, bitumen reflectance determinations for Taq Taq-22 indicate an equivalent vitrinite reflectance maturity of no more than 0.93%Ro, which is significantly less than that of the indigenous vitrinite, implying the solid bitumen in this well is derived primarily from migrated hydrocarbons. Further detailed analysis is required, but the results suggest that the Baluti Formation may have sourced hydrocarbons in its depocentre which is identified in this study as covering a NW-SE trending area between Bekhme and Sangaw.  相似文献   
7.
AIM: To evaluate the anti-inflammatory cytokine interleukin-13 (IL-13) for the treatment of uveitis. METHODS: Uveitis was induced in monkeys by immunisation with human retinal S-antigen. Starting at the onset of disease, the animals were treated with IL-13 at 25 micrograms/kg, or vehicle control, injected subcutaneously once a day for 28 days. Intraocular inflammation was scored by indirect ophthalmoscopy for a period of 56 days. Circulating leucocyte levels were monitored. RESULTS: Uveitis started unilaterally in all but one animal. IL-13 inhibited inflammation both in the eyes in which the disease was present when the treatment was initiated (p = 0.0001), and in the contralateral initially negative eyes (p = 0.0001). After cessation of therapy, there was a progressive increase of inflammation in the IL-13 treated group. However, the beneficial effect of IL-13 extended into the 4 week follow up period. IL-13 produced an increase in circulating polymorphonuclear neutrophils and a decrease in lymphocytes. CONCLUSION: Administration of IL-13 appears to be a promising modality of treatment for severe uveitis.  相似文献   
8.
Analog methods for computation of the generalized inverse   总被引:2,自引:0,他引:2  
In this paper some properties of the generalized matrix inverse are discussed leading up to two analog techniques for its computation. Analog procedures are given for the computation of the unique vectorxof least Euclidean norm that minimizes the Euclidean norm of the error vectorAx - b.  相似文献   
9.
Physical and geochemical properties were performed on three crude oils from Alif-01 well in the Marib sub-basin. The analyzed samples comprise medium specific gravity (37° API), reflecting mature source rocks. The thermal maturity of the analyzed oils is also indicated from the high content of aliphatic hydrocarbons (HC). The compositions of HC further suggest that analyzed oils belong to paraffinic oils. The n-alkane and isoprenoid distributions reveal that the analyzed oils are derived from marine source rock, containing mixed organic matter, with some terrestrial input and deposited under relatively reducing conditions. The features of the analyzed oils are consistent with the Madbi source rock characteristics in the basin.  相似文献   
10.
Malek  S.  Pajouh  H. Hakimi 《Semiconductors》2021,55(3):301-307
Semiconductors - The propagation of solitary acoustic pulses in magnetized quantum electron–hole plasmas of semiconductors has been studied. The effects of an external magnetic field and...  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