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61.
62.
双组分树脂冷压法制备摩擦材料 总被引:8,自引:0,他引:8
研究甲、乙双组分液体树脂作为粘结剂制备制动摩擦材料的冷压工艺方法,甲组分树脂为硼改性腰果壳油树脂,乙组分树脂为三聚氰胺改性酚醛树脂。该工艺可使模压料在室温下具有良好的成型效果,在固化处理中不使用夹具,可以使成型料具有良好的保型效果。冷压制备的制动摩擦材料具有硬度低、摩擦系数稳定和恢复性好等特点。 相似文献
63.
This paper derives the admissible decompositions for a time series dynamic linear model, assuming only that the model is observable. The decompositions depend on factorizations of the characteristic polynomial of the state evolution matrix G into relatively prime factors. This generalizes the method of West (1997 ) which considers one decomposition in the particular case where G is diagonalizable. Conditions are derived for a decomposition to be independent. These results show that no autoregressive process of order d has an independent decomposition for any integer d . Two illustrations of this procedure are discussed in detail. 相似文献
64.
简述了上海汽轮机有限公司(STC)与西门子公司首次合作制造的目前国内最大容量的外高桥900MW超临界机组的一些基本情况,介绍了在合作制造中为保证生产进度和质量而采取的工艺改进、技术攻关等措施,以及通过合作制造提升了我公司的制造能力和管理水平。 相似文献
65.
XIAN He-qun FENG Deng-guo 《通讯和计算机》2007,4(3):44-51
Even with attractive computational advantages, mobile agent technology has not developed its full potential due to various security issues. This paper proposes a method called Private Key Consignment to solve the problem of how to protect the data carried by mobile agents. It exploits new functionalities and mechanism provided by the trusted computing technology, and adopts both public key and symmetric key cryptographic means for data and key protection. The most notable feature of this method is that it protects the private key of the agent by consigning it to a tamper proof hardware, thus, enabling convenient and secure use of the private key. It provides a new scheme of mobile agents' data protection. 相似文献
66.
Abstract. This article proposes an extension to scalar component methodology for the identification and estimation of VARMA models. The complete methodology determines the exact positions of all free parameters in any VARMA model with a predetermined embedded scalar component structure. This leads to an exactly identified system of equations that is estimated using full information maximum likelihood. 相似文献
67.
An upper-bound analysis of the pressure-assisted injection forging (PAIF) of thick-walled tubular components with hollow flanges was conducted to predict the maximum forming-pressure requirements. The polymeric pressurizing material and the pure aluminium work material employed were assumed to obey the von-Mises’ yield criterion, the two materials being divided into three and six zones, respectively, and described using kinematically admissible velocity fields. An upper-bound solution was derived based on this model. Experiments were conducted to validate the solution. The results suggest that the upper-bound analysis has sufficient accuracy for the prediction of the forming-pressure requirements. Subsequently, a parametric analysis was conducted to study the effects of variation of the principal parameters of the process and the geometry, such as tube thicknesses, flange dimensions and friction, on the forming-force requirements, which showed other useful applications of the upper-bound solutions. 相似文献
68.
Fourteen commercial polyadipates and a polysebacate were analysed for their components of a molecular mass below 1000 Da, primarily with the aim of generating the background data for measuring the migration of this type of polymeric additives from plasticized PVC (e.g. cling films and gaskets of lids) into foods or food simulants. Since the composition of the material <1000 Da varies between the polyadipates, the main components must be identified to enable a correct quantification. Polyadipates differ in the diol used as linker, their termination (acid or alcohol) and in the end‐capping (free alcohols, acetylation, acylation with fatty acids, esterification with octanol/decanol). Gas chromatography (GC) provides good separation, but the material remaining in the column up to high temperatures decomposes and forms a hump in the rear part of the chromatogram. Examples of mass spectra are shown, the most indicative fragments pointed out and spectra of 159 components listed. The polyadipates and the sebacate are characterized by their structure, the main components <1000 Da and the fraction of material <1000 Da. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
69.
Quantitative gas chromatographic analysis of the volatile aroma components has been used as an objective measure of the effects of maturity at harvest, ripeness and storage on the aroma volatiles of kiwifruit. Increasing ripeness is associated with a rapid increase in the levels of aroma volatiles, especially esters, while increasing storage time prior to ripening is accompanied by a decrease in the amount of aroma volatiles. 相似文献
70.
Harvesting experiments revealed that immature whole mushrooms with closed veils had higher 1-octen-3-0l levels than more mature whole mushrooms with open veils. The l-octen-3-01 content of the gills was higher in immature mushrooms with closed veils, gradually decreased with maturity as the veil opened, and finally increased after the gills were well exposed. Postharvest experiments demonstrated that storage temperature influenced the activity of lipoxygenase-hydroperoxide lyase, but no differences in 1-octen-3-01 content were observed. Enzyme activity as well as 1-octen-3-01 content decreased during storage. Addition of calcium chloride to irrigation water, employed to improve quality and shelf life of fresh mushrooms, increased the amount of l-octen-3-01 immediately after harvest. 相似文献