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排序方式: 共有452条查询结果,搜索用时 15 毫秒
51.
Constantin Turta Silvia Melnic Denis Prodius Fliur Macaev Helene Stoeckli-Evans Patricia Ruiz Dmitry Muraviev Serghei Pogrebnoi Zinaida Ribkovskaia Valeriu Mereacre Yanhua Lan Annie K. Powell 《Inorganic chemistry communications》2010,13(12):1402-1405
High-temperature solution phase reaction of iron(III)-furoate in sunflower oil, in the presence of trichloroacetic acid and 1,2-hexadecylamine leads to iron(III) oxide (amorphous and γ-Fe2O3) nanoparticles with sizes about 1.3 nm in diameter (method “A”), and about 5.5 nm (amorphous Fe2O3) from the “sunflower oil/oxadiazol” system (method “B”). 相似文献
52.
法国里莫酒业集团,始建于1789年,在国际葡萄酒界久享盛名,是一家集葡萄栽培、酿造、技术输出为一体的大型跨国集团,盛产各种名贵干红、干白、玫瑰红葡萄酒,是世界上最大的葡萄酒出口企业和跨国集团之一,同时也是法国和欧洲最大的用单一葡萄酿酒的生产型企业。畅销全球104个国家和地区,年出口5800万瓶。在世界各地平均每22支已开瓶的葡萄酒中即有一支为本集团出品,平均每秒钟都有人在饮用本集团出品的优质葡萄酒。
里莫集团拥有世界上最先进的生产流水线,葡萄种植面积达52500亩,葡萄园1000多个,有1000多年的种植史,且拥有先进的葡萄酒酿造及品质控制和保障中心。严格按照国际OIV标准,从葡萄的种植、采摘、加工到酒的酿制、装瓶检验全过程采用电脑自动化控制,每一瓶葡萄酒的品质在保质期内承诺百分之百的质量保证。其酿造的“马迪尔”、“马妮尔”葡萄酒,拥有一项世界第一,三项国际金奖的称号,是葡萄酒中难得一见的珍品。
目前,里莫集团在亚洲的销售网络已遍及日本、韩国、香港、澳门、新加坡、马来西亚、泰国等国家。近年来,法国里莫酒业集团非常关注中国的快速发展,并在中国建立了营销机构——杭州马迪尔酒业有限公司,已叩开了进入中国市场的大门。[编者按] 相似文献
53.
M. G. Umamaheswari G. Uma L. Annie Isabella 《Journal of Computational Electronics》2014,13(1):142-154
A digital predictive control strategy for Power Factor Correction (PFC) is presented in this paper. The duty cycles required to achieve unity power factor in one half line period are calculated in advance by using a predictive algorithm and implemented using low cost PIC Microcontroller. A single stage PFC circuit controlled by these pre-calculated duty cycles can achieve sinusoidal current waveform. The output voltage of PFC circuit is regulated by an outer PI controller. A low frequency, small signal model of the rectifier is developed in order to design a PI voltage controller. A prototype of front end AC–DC converter followed by DC–DC Cuk converter controlled by a PIC Microcontroller is developed. Both the simulation and experimental results reveal that the proposed digital predictive strategy provides low THD, high power factor and better performance due to its lower calculation requirement and simple implementation. 相似文献
54.
Transition metal ferrocyanides have important applications in the selective removal of radioactive caesium from low level and intermediate level radioactive liquid waste streams. The microcrystalline nature of these materials renders them useless for application in column mode operations. Special preparation procedures have been developed to prepare granular solids by in situ precipitation of metal ferrocyanides on organic anion exchangers, which is suitable for column mode operations. The elemental compositions of the metal ferrocyanides precipitated inside the pores of anion exchanger were determined by analysing the dissolved samples using ICP-AES system and flame photometer. From the XRD and EDX analyses and the elemental composition of the synthesized materials, the nature of the compound formed inside the anion exchanger was found to be cobalt ferrocyanide. From SEM analysis of the samples, the particle size of the cobalt ferrocyanide precipitated inside the anion exchanger was found to be much less than that of cobalt ferrocyanide precipitated outside. The efficiency of these materials for removal of Cs was evaluated by measuring the distribution coefficient (Kd), ion exchange capacity and kinetics of Cs uptake. The Kd of the materials loaded on anion exchanger was found to be of the order of 105 ml/g. The Cs uptake kinetics of the materials loaded on anion exchanger was slower than that of precipitated materials. The ion exchange capacity of the cobalt ferrocyanide loaded on anion exchanger was found to be much higher than that of the precipitated cobalt ferrocyanide. 相似文献
55.
Saint-Aubin Jean; Klein Raymond M.; Roy-Charland Annie 《Canadian Metallurgical Quarterly》2003,29(6):1191
When participants search for a target letter while reading, they make more omissions if the target letter is embedded in frequently used words or in the most frequent meaning of a polysemic word. According to the processing time hypothesis, this occurs because familiar words and meanings are identified faster, leaving less time for letter identification. Contrary to the predictions of the processing time hypothesis, with a rapid serial visual presentation procedure, participants were slower at detecting target letters for more frequent words or the most frequent meaning of a word (Experiments 1 and 2) or at detecting the word itself instead of a target letter (Experiment 3). In Experiments 4 and 5, participants self-initiated the presentation of each word, and the same pattern of results was observed as in Experiments 1 and 3. Positive correlations were also found between omission rate and response latencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
Schroeder Jennifer R.; Gupman Anne E.; Epstein David H.; Umbricht Annie; Preston Kenzie L. 《Canadian Metallurgical Quarterly》2003,11(3):195
Data from 2 contingency management trials, targeting opiate or cocaine use, were used to investigate whether noncontingent vouchers inadvertently reinforce drug use. The control group in each trial received noncontingent vouchers matched in value and frequency to those received by experimental groups, but independent of urinalysis. Vouchers were offered thrice weekly for 8 weeks (opiates) or 12 weeks (cocaine). Both dose-response and temporal associations of noncontingent voucher receipt with drug-positive urines were assessed. Drug use was unrelated to frequency of noncontingent voucher delivery and noncontingent voucher receipt when being drug positive was unassociated with risk of subsequent drug use, with one exception: cocaine use in the cocaine study (relative risk = 1.05, 95% confidence interval: 1.01-1.09). Overall, results do not indicate a causal relationship between noncontingent voucher receipt and increased drug use. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
57.
Minimal schedulability interval for real-time systems of periodic tasks with offsets 总被引:1,自引:0,他引:1
We consider real-time systems in highly safety context where tasks have to meet strict deadlines. Tasks are periodic, may have offsets, share critical resources and be precedence constrained. Off-line scheduling should be of great help for such systems, but methods proposed in the literature cannot deal with them. Our aim is to extend and improve the well-known cyclicity result of Leung and Merill to every scheduling algorithm and to systems of interacting tasks with offsets. One of the main benefit of our result is to enable the use of off-line scheduling methods for those real-time critical systems. 相似文献
58.
Abstract. The purpose of this paper is to discuss several fundamental issues in the theory of time-dependent spectra for univariate and multivariate non-stationary processes. The general framework is provided by Priestley's evolutionary spectral theory which is based on a family of stochastic integral representations. A particular spectral density function can be obtained from the Wold—Cramér decomposition, as illustrated by several examples. It is shown why the coherence is time invariant in the evolutionary theory and how the theory can be generalized so that the coherence becomes time dependent. Statistical estimation of the spectrum is also considered. An improved upper bound for the bias due to non-stationarity is obtained which does not rely on the characteristic width of the process. The results obtained in the paper are illustrated using time series simulated from an evolving bivariate autoregressive moving-average process of order (1, 1) with a highly time-varying coherence. 相似文献
59.
Powell BA Dai Z Zavarin M Zhao P Kersting AB 《Environmental science & technology》2011,45(7):2698-2703
The subsurface migration of Pu may be enhanced by the presence of colloidal forms of Pu. Therefore, complete evaluation of the risk posed by subsurface Pu contamination needs to include a detailed physical/chemical understanding of Pu colloid formation and interactions of Pu colloids with environmentally relevant solid phases. Transmission electron microscopy (TEM) was used to characterize Pu nanocolloids and interactions of Pu nanocolloids with goethite and quartz. We report that intrinsic Pu nanocolloids generated in the absence of goethite or quartz were 2-5 nm in diameter, and both electron diffraction analysis and HRTEM confirm the expected Fm3m space group with the fcc, PuO2 structure. Plutonium nanocolloids formed on goethite have undergone a lattice distortion relative to the ideal fluorite-type structure, fcc, PuO2, resulting in the formation of a bcc, Pu4O7 structure. This structural distortion results from an epitaxial growth of the plutonium colloid on goethite, leading to stronger binding of plutonium to goethite compared with other minerals such as quartz, where the distortion was not observed. This finding provides new insight for understanding how molecular-scale behavior at the mineral-water interface may facilitate transport of plutonium at the field scale. 相似文献
60.
Discusses the effects of motivation on ability to sustain attention. We emphasize the fact that motivation should be considered a masking factor in ultradian rhythmicities of cognitive efficiency. In the first part of this article, several studies are listed. These studies attempted to show behavioral fluctuations when sustained attention is required. The inconsistency of the results brought forth by such studies is pointed out. In the second part of the article, the question of the status granted to motivation in chronopsychological studies, where motivation is manipulated in several ways, is discussed. Interpretations are revisited in terms of intrinsic and/or extrinsic motivation concepts. Some of these chronopsychological studies used only extrinsic motivation whereas others created conditions in which intrinsic motivation was favoured (for example, knowledge of results, which appears to be a prominent masking factor). Finally, we propose several hypotheses in order to support the assumption of a stabilizing effect provided by intrinsic motivation. We conclude by insisting upon the necessity of involving participants in tasks requiring complex cognitive activity, which contrasts with the monotonous and too simple tasks used frequently in chronopsychological studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献