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排序方式: 共有230条查询结果,搜索用时 78 毫秒
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SA Syed KS Zahir JR Zink O Saglaam RJ Restifo JG Thomson 《Canadian Metallurgical Quarterly》1997,38(4):396-403
Reinstatement and spontaneous recovery of previously extinguished nicotine-taking behavior were examined in rats. Male subjects were trained to self-administer nicotine (30 microg/kg per infusion, IV; one 60-min session per day for 3 weeks). Extinction sessions were then given for 5-10 days during which saline was substituted for nicotine. Subsequently, in the first set of tests for nicotine seeking, the reinstatement of lever presses that previously delivered nicotine was examined after priming injections of saline and nicotine (75, 150 and 300 microg/kg, SC; and 30 and 60 microg/kg, IV). In the second set of tests for nicotine-seeking, rats were tested after an additional 21-day drug-free period during which they were not exposed to the self-administration chambers (a test for the spontaneous recovery of drug seeking), and after priming injections of nicotine (150 and 300 microg/kg, SC). Reinstatement of extinguished food-reinforced behavior after exposure to nicotine was also determined. Priming injections of nicotine reinstated nicotine seeking regardless of the route of administration. In addition, previously extinguished nicotine seeking recovered spontaneously after a 21-day period during which rats were not exposed to the drug-taking environment. Nicotine also reinstated extinguished food-reinforced behavior in rats with a history of nicotine self-administration, but not in drug-naive rats. The present results extend previous work with opioid and stimulant drugs on reinstatement of drug seeking by the self-administered drug. It also appears that, as with other positive reinforcers, the mere passage of time is a sufficient condition for the spontaneous recovery of extinguished nicotine seeking. 相似文献
3.
M. Bounoughaz E. Salhi K. Benzine E. Ghali F. Dalard 《Journal of Materials Science》2003,38(6):1139-1145
Zinc is used in the oil industry as a sacrificial anode for protecting steel storage tanks from corrosion. The behaviour of a sample of zinc from the Algerian metallurgy industry (zinc A) and a commercially available zinc (zinc B) was compared in an electrolyte from storage tank drainage water. The corrosion potential measurements for zinc A confirmed that this material could be used as a sacrificial anode. The polarization curves of the two materials (zinc A and zinc B) were different, zinc A being the least polarized. Thus, the same corrosion protection could be obtained with a lower surface ratio (S
Zn/S
Fe) for Zinc A. Cyclic voltammetry curves provided evidence of a surface layer formed by dissolution products. To provide protection over extended periods of time, the zinc anode must be oversized. The two types of zinc tested were comparable.The results of the impedance spectroscopy study confirmed the previous results. The corrosion layer formed on zinc A was not prejudicial to dissolution. Hence, the properties of this zinc were found to be satisfactory for its use as a sacrificial anode. 相似文献
4.
The content and positional distribution of CLA in TAG fractions of lamb tissues was examined with either preformed CLA or
the linoleic acid precursor of CLA in the diet as experimental treatments. The CLA content of phospholipid (PL) from these
tissues was also examined. Thirteen lambs were randomized to the following dietary treatments: (i) control diet (no supplement);
(ii) CLA supplementation (0.33 g d−1 for 21 d prior to weaning) to milk-replacer of pre-ruminating lambs, or (iii) feeding linoleic acid-rich oil (6% safflower
oil on a dry matter basis) to weaned ruminating lambs. At slaughter, tissue samples were procured from diaphragm, rib muscle,
and subcutaneous (SC) adipose tissue. Safflower oil supplementation in the diet resulted in an increase in CLA content of
the TAG from diaphragm, rib muscle, and SC adipose tissue by about threefold (P<0.05) on a mol% basis. CLA was localized to the sn-1/3 positions of TAG. Animals that received pre-formed CLA, however, had increased proportions of CLA at the sn-2 position of TAG from SC adipose tissue, suggesting that there were tissue-specific dietary effects and possible age-related
effects on the mode of FA incorporation into TAG. Safflower oil supplementation in the diet had no effect on the CLA content
of PL from diaphragm, rib muscle, and SC adipose tissue, suggesting that CLA was preferentially incorporated into the TAG
of these tissues. 相似文献
5.
Vishanth Weerakkody Zahir Irani Habin Lee Nitham Hindi Ibrahim Osman 《Information Systems Management》2016,33(4):331-343
Citizens’ satisfaction is acknowledged as one of the most significant influences for e-government adoption and diffusion. This study examines the impact of information quality, system quality, trust, and cost on user satisfaction of e-government services. Using a survey, this study collected 1518 valid responses from e-government service adopters across the United Kingdom. Our empirical outcomes show the five factors identified in this study have a significant impact on U.K. citizens’ satisfaction with e-government services. 相似文献
6.
The vehicle routing problem with deliveries and pickups is one of the main problems within reverse logistics. This paper focuses on an important assumption that divides the literature on the topic, namely the restriction that all deliveries must be completed before pickups can be made. A generalised model is presented, together with a mathematical formulation and its resolution. The latter is carried out by adopting a suitable implementation of the reactive tabu search metaheuristic. Results show that significant savings can be achieved by allowing a mixture of delivery and pickup loads on-board and yet not incurring delays and driver inconvenience. 相似文献
7.
Adil Fahad Zahir Tari Ibrahim Khalil Ibrahim Habib Hussein Alnuweiri 《Computer Networks》2013,57(9):2040-2057
There is significant interest in the network management and industrial security community about the need to identify the “best” and most relevant features for network traffic in order to properly characterize user behaviour and predict future traffic. The ability to eliminate redundant features is an important Machine Learning (ML) task because it helps to identify the best features in order to improve the classification accuracy as well as to reduce the computational complexity related to the construction of the classifier. In practice, feature selection (FS) techniques can be used as a preprocessing step to eliminate irrelevant features and as a knowledge discovery tool to reveal the “best” features in many soft computing applications. In this paper, we investigate the advantages and disadvantages of such FS techniques with new proposed metrics (namely goodness, stability and similarity). We continue our efforts toward developing an integrated FS technique that is built on the key strengths of existing FS techniques. A novel way is proposed to identify efficiently and accurately the “best” features by first combining the results of some well-known FS techniques to find consistent features, and then use the proposed concept of support to select a smallest set of features and cover data optimality. The empirical study over ten high-dimensional network traffic data sets demonstrates significant gain in accuracy and improved run-time performance of a classifier compared to individual results produced by some well-known FS techniques. 相似文献
8.
Microprocessors continue on the relentless path to provide more performance. Every new innovation in computing-distributed computing on the Internet, data mining, Java programming, and multimedia data streams-requires more cycles and computing power. Even traditional applications such as databases and numerically intensive codes present increasing problem sizes that drive demand for higher performance. Design innovations, compiler technology, manufacturing process improvements, and integrated circuit advances have been driving exponential performance increases in microprocessors. To continue this growth in the future, Hewlett Packard and Intel architects examined barriers in contemporary designs and found that instruction-level parallelism (ILP) can be exploited for further performance increases. This article examines the motivation, operation, and benefits of the major features of IA-64. Intel's IA-64 manual provides a complete specification of the IA-64 architecture 相似文献
9.
Sofiane Guessasma Zahir Salhi Ghislain Montavon Patrick Gougeon Christian Coddet 《Materials Science and Engineering: B》2004,110(3):285-295
Thermal spray process is a technique of coating manufacturing implementing a wide variety of materials and processes. This technique is characterized by up to 150 processing parameters influencing the coating properties. The control of the coating quality is needed through the consideration of a robust methodology that takes into account the parameter interdependencies, the process variability and offers the ability to quantify the processing parameter-process response relationships. The aim of this work is to introduce a new approach based on artificial intelligence responding to these requirements. A detailed procedure is presented considering an artificial neural network (ANN) structure which encodes implicitly the physical phenomena governing the process. The implementation of such a structure was coupled to experimental results of an optic sensor controlling the powder particle fusion state before the coating formation. The optimization steps were discussed and the predicted results were compared to the experimental ones allowing the identification of the control factors. 相似文献
10.
Slim Salhi Jihen Mahfoudh Souhir Abid Leonard‐Ionut Atanase Marcel Popa Christelle Delaite 《Polymer International》2020,69(11):1161-1168
A series of random polyesteramides (PEAs) with a range of molar composition from 90/10 to 50/50 were synthesized by direct melt polycondensation of ε‐caprolactone and l ‐alanine. Their structure was fully characterized by Fourier transform IR and NMR spectroscopy. The resulting copolymers are completely amorphous with the exception of PEA‐90/10 which possesses a semicrystalline structure. These PEAs present increasing glass transition temperatures at increasing l ‐alanine contents and exhibit fairly good thermal stability with 10% mass loss temperatures reaching 315 °C. © 2020 Society of Industrial Chemistry 相似文献