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71.
Toughening mechanism for a rubber-toughened epoxy resin with rubber/matrix interfacial modification 总被引:1,自引:0,他引:1
For a rubber-toughened piperidine-DGEBA epoxy resin, the interface between the rubber particle and the epoxy resin matrix was modified by an epoxide end-capped carboxyl terminated butadiene and acrylonitrile random copolymer (CTBN). The end-capping epoxides used were a rigid diglycidyl ether of bisphenol-A (Epon 828), a short-chain flexible diglycidyl ether of propylene glycol (DER 736), and a long-chain flexible diglycidyl ether of propylene glycol (DER 732). The microstructures and the fracture behaviour of these rubber-modified epoxy resins were studied by transmission electron microscopy and scanning electron microscopy. Their thermal and mechanical properties were also investigated. In the rubber-modified epoxy resins, if the added CTBNs were end-capped by a flexible diglycidyl ether of propylene glycol (DER 732 or DER 736) before curing, the interfacial zone of the undeformed rubber particle, the degree of cavitation of the cavitated rubber particle on the fracture surface and the fracture energy of the toughened epoxy resin were all significantly increased. The toughening mechanism based on cavitation and localized shear yielding was considered and a mechanism for the interaction between cavitation and localized shear yielding that accounts for all the observed characteristics is proposed. 相似文献
72.
Web服务在信用信息工程中的应用 总被引:2,自引:2,他引:0
目前的社会信用信息工程中,许多的政府部门都建立了自己的信用信息数据库,但在政府各级部门数据库之间进行数据交流和共享存在着许多的问题,在许多地方,数据共享还是一片空白。Web服务技术是应用程序通过内联网或者因特网发布和利用软件服务的一种标准机制。利用WEB服务可以方便地实现不同系统之间的数据交换和集成。该文提出利用web服务技术来解决信用信息工程中的信息数据共享问题。并在此基础上提出利用WEB服务工作流技术将信用评估整合到电子商务过程,以实现可信用电子商务 相似文献
73.
Kubat M. Hafez A. Raghavan V.V. Lekkala J.R. Wei Kian Chen 《Knowledge and Data Engineering, IEEE Transactions on》2003,15(6):1522-1534
Association mining techniques search for groups of frequently co-occurring items in a market-basket type of data and turn these groups into business-oriented rules. Previous research has focused predominantly on how to obtain exhaustive lists of such associations. However, users often prefer a quick response to targeted queries. For instance, they may want to learn about the buying habits of customers that frequently purchase cereals and fruits. To expedite the processing of such queries, we propose an approach that converts the market-basket database into an itemset tree. Experiments indicate that the targeted queries are answered in a time that is roughly linear in the number of market baskets, N. Also, the construction of the itemset tree has O(N) space and time requirements. Some useful theoretical properties are proven. 相似文献
74.
Hong Long Chen 《Canadian Metallurgical Quarterly》2007,23(4):171-181
The difficulty in applying the standard curve (S-curve) and cost-schedule integration (CSI) techniques for company-level cost flow forecasting in a project-based industry is the prerequisite of forecasting future unknown individual projects and contract classifications. By analyzing cost flows at the company level through a pool of macroeconomic and internal financial data, this paper proposes an innovative approach to firm-specific model estimation. First, a series of data transformations introduce linear relationships between cost, macroeconomic, and internal financial variables. Second, multivariate regression analysis is employed for initial model building. Third, for the purposes of model restructuring, a subsequent application of Yule–Walker estimates and incomplete principal component analysis is used. This paper uses a sample of four project-based construction firms to demonstrate model performance. Using this methodology, mean absolute percentage error (MAPE) values of the forecasting models range from 0.27 to 0.60%. As such, the transformed cost, macroeconomic, internal financial data could strongly predict company-level cost flow forecasting. While converting the predicted cumulative cost data to periodic cost flows, the MAPE values were augmented, ranging from 7.04 to 17.55%, thus, requiring future research. 相似文献
75.
eCRM (electronic Customer Relationship Management) systems focus on using the web-site as the main interaction channel for businesses to simulate an old fashioned one-to-one direct relationship—high touch—with customers. In this research two distinct but related concepts, media richness from the Human Computer Interaction and Computer Mediated Communication fields and perceived interactivity from the Marketing and MIS fields, are disentangled and their unique impacts on technology acceptance variables are examined in the eCRM Acceptance Model. The present study contributes in extending the Technology Acceptance Model for the eCRM context and in establishing media richness and perceived interactivity as antecedents to perceived usefulness and perceived ease of use. Our research model integrates system perception (e.g., perceived usefulness and perceived ease of use) and subjective outcome measures (e.g., decision satisfaction) in a single model to fully understand the impact of eCRM “touch” design perceived by e-customers on their intention to return after the initial visit. An experimental survey of two culture groups (independent vs. interdependent self-construal) of technology savvy, young college students reveals that culture value-orientation (e.g., self-construal) moderates the effect of decision satisfaction on behavior intention to return in our eCRM Acceptance model. Findings of this research thus have significant theoretical and managerial implications. 相似文献
76.
77.
Yi‐Hung Chen Ching‐Yuan Chang Wei‐Ling Su Chun‐Yu Chiu Yue‐Hwa Yu Pen‐Chi Chiang Chiung‐Fen Chang Je‐Lueng Shie Chyow‐San Chiou Sally IM Chiang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(1):68-75
This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry 相似文献
78.
Xi-Ren Cao Han-Fu Chen 《Automatic Control, IEEE Transactions on》1997,42(10):1382-1393
Two fundamental concepts and quantities, realization factors and performance potentials, are introduced for Markov processes. The relations among these two quantities and the group inverse of the infinitesimal generator are studied. It is shown that the sensitivity of the steady-state performance with respect to the change of the infinitesimal generator can be easily calculated by using either of these three quantities and that these quantities can be estimated by analyzing a single sample path of a Markov process. Based on these results, algorithms for estimating performance sensitivities on a single sample path of a Markov process can be proposed. The potentials in this paper are defined through realization factors and are shown to be the same as those defined by Poisson equations. The results provide a uniform framework of perturbation realization for infinitesimal perturbation analysis (IPA) and non-IPA approaches to the sensitivity analysis of steady-state performance; they also provide a theoretical background for the PA algorithms developed in recent years 相似文献
79.
Jenghwa Chang Graber H.L. Ping Chen Koo Aronson R. Barbour S.-L.S. Barbour R.L. 《IEEE transactions on medical imaging》1997,16(1):68-77
Presents a model suitable for computing images of absorption cross sections of thick tissue structures illuminated at near infrared (NIR) wavelengths from tomographic projection data. Image reconstruction is accomplished by solving a system of linear equations derived from transport theory. Reconstruction results using different algebraic solvers are shown for anatomical maps of the breast, derived from magnetic resonance imaging data, containing two simulated pathologies, in which case qualitatively good reconstructions were obtained. Evaluation of magnetic resonance (MR) data to optimize NIR optical tomographic imaging methods and to assess the feasibility of a combined MR-optical measurement scheme is discussed 相似文献
80.
RT-AGVS是物流管理中十分重要的课题,车辆位置监测网是其重要的组成部分。本文详细介绍了一个基于单片机系统的车辆位置实时监测网,本监测网设计先进,性能价格比高,它的设计方法和技术对其他许多领域有借鉴作用。 相似文献