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排序方式: 共有6592条查询结果,搜索用时 31 毫秒
51.
Elena Crespi Antonio Capolongo Davide Fissore Antonello A. Barresi 《Drying Technology》2008,26(3):349-356
The aim of this article is to develop an experiment and a procedure to investigate the restoration of water-damaged paper and archival materials using freeze drying in order to allow a reproducible test and comparison of the influence of different operating conditions on drying time and restored paper quality. Firstly, a reproducible method for the preparation of soaked samples simulating water-damaged paper has been developed. Then, the samples have been freeze-dried in a laboratory-scale apparatus that allowed monitoring the temperature as well as the weight of the samples. The technique of evaporative freezing, which reduces the drying time required, has been used in this case. An innovative procedure for the visualization of the progress of the drying process has been validated, thus allowing the validation of a simple phenomenological model of the time evolution of the ice core volume; in addition, data on the residual moisture of the dried paper sheets in different zones have been given. Finally, optimization of this particular drying process by using simple or more sophisticated approaches has been discussed. 相似文献
52.
The effective thermal diffusivity of foodstuffs was estimated from time-temperature histories in the geometric center of samples exposed to heating and cooling processes.Transfer functions methodology was used as an alternative method to estimate the thermal diffusivity assuming that conduction was the main heat transfer mechanism. The samples were characterized as delayed first-order systems with unit gain, dead time (L) and time constant (τ).The results were compared with those obtained from the fh value and with results reported in the literature. 相似文献
53.
Imperfection in information can be considered a crosscutting concern that manifests itself in diverse kinds of imprecision, uncertainty, or inconsistency in the data models of a software system. The extension of existing programming and querying interfaces for the different aspects of information imperfection requires a proper modularization of the different concerns of numerical imprecision handling, so that the extensions do not interfere with existing programming practices and do not obscure the original design. Aspect‐oriented design (AOD) enables such a form of nonintrusive extensions to be added to existing software libraries, clearly separating fuzziness or other imperfections in data as a differentiated concern that can be considered from the early phases of development. In this article, a general framework for aspect‐based extension of data models and fuzzy databases is described, and some design and implementation issues of such AOD‐based extensions on OJB database libraries are described as a case study. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1199–1216, 2006. 相似文献
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P Uribe-Zú?iga G Hernández-Tepichín C del Río-Chiriboga V Ortiz 《Canadian Metallurgical Quarterly》1995,37(6):592-601
Since 1987 The National AIDS Council in Mexico (CONASIDA), has conducted research projects among female commercial sex workers (CSW), who are seen at the AIDS Information Centers. Through these studies, we have been able to find out how different issues influence commercial sex work in Mexico City. Since the beginning of our own studies in 1989, HIV prevalence in this particular group has remained low (0.04%-0.2%). Factors found to be associated with condom use were: educational level, not having children, more experience in sex work and younger age. Condom use was reported by 88% of the women; however, qualitative information and high STD prevalence rates suggest a much lower condom use. Mandatory HIV testing is not useful as a preventive measure among sex workers. Persuasive and structural interventions must be implemented in accordance with local and legal situations. 相似文献
56.
ME Martínez S Medina MT del Campo MJ Sánchez-Cabezudo M Sánchez L Munuera 《Canadian Metallurgical Quarterly》1998,62(5):453-456
BACKGROUND AND STUDY AIMS: Anastomotic leakage is a severe complication in gastric surgery and it is associated with a high rate of mortality. Conservative treatment sometimes is not sufficient to stem the leakages and, even when it is sufficient, it takes a long time. The present study describes the first experience in the treatment of anastomotic leakages with endoscopic clipping. PATIENTS AND METHODS: From May 1995 to December 1996, seven patients with postoperative anastomotic leakages after gastric surgery were prospectively treated in our Endoscopy Service. Metallic endoclips (MD 850, Olympus Corp., Tokyo, Japan) with prongs 12 mm long and 6 mm wide were applied, controlling the closure of the leakage by endoscopy, using radiographs to confirm the closure 24 hours later. RESULTS: Complete closure of the leakage was obtained in all seven cases. A single session of endoscopic clipping was needed for five patients while two other required, respectively, two and three sessions. The median time of leakage closure after endoscopic clipping was 2.3 days (range 1-5 days). The clips spontaneously dislodged within 1 month in five patients and within the second month in the other two patients. CONCLUSION: Endoscopic treatment of anastomotic leakages by metallic clips represents a safe and easily repeated method and, compared to conservative treatment, it seems to offer several time and cost advantages. Further studies involving a larger number of patients are needed to verify this finding. 相似文献
57.
FR del Valle M Escobedo A Sanchez-Marroquin H Bourges MA Bock P Biemer 《Canadian Metallurgical Quarterly》1993,43(2):145-156
The objective of this study was to calculate, prepare and evaluate the Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) of two infant formulas made with amaranth (Amaranthus cruentus). Both formulas were formulated to match a previously developed and tested soy-oats infant formula. No significant differences were found between the three formulas with respect to corrected Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) values. Only the product made with the 1-R fraction of amaranth was found to have a significantly lower P.E.R. than casein. 相似文献
58.
Designing Templates for Mining Association Rules 总被引:3,自引:0,他引:3
Current approaches to data mining usually address specific userrequests, while no general design criteria for the extraction of associationrules are available for the end-user. In this paper, we propose aclassification of association rule types, which provides a general frameworkfor the design of association rule mining applications. Based on theidentified association rule types, we introduce predefined templates as ameans to capture the user specification of mining applications. Furthermore,we propose a general language to design templates for the extraction ofarbitrary association rule types. 相似文献
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