MODELING METHOD OF 4D INFORMATION MODEL FOR COOPERATIVE DESIGN OF MECHANICAL PRODUCTS

The continuous developing features in the design of mechanical product and based on 3D entity model is aimed at, and the extension of the 4-dimensional model with the process of designing, the knowledge described model on the level of semantic understanding and summarizing the designing process and the way of discovering knowledge from multi-information model are studied. On the basis of designing the broad sensed collaborative system, through discussion of the relationship between the implicit knowledge of the users and the designing knowledge as well as commanding all the designing links, taking advantage of the way of concluding and deducting in the concept of the designers, the synthetic knowledge unit formed in the dynamic process from the conception design to the last design is schemed out, and the knowledge discovered principle in the dynamic designing process of the mechanical products and the key technology in its implementation under the milieu of network is brought forward.     

Oligomer Distribution at the Gel Point of Tannin-resorcinol-formaldehyde Cold-Set Wood Adhesives

Tannin-resorcinol-formaldehyde cold-set adhesives for wood laminating and fingerjointing were examined by Matrix Assisted Laser Desorption/Ionisation Time of Flight (MALDI-TOF) mass spectrometry. The analysis revealed that the adhesive was composed at the gel point of resorcinol-formaldehyde oligomers, unreacted flavonoids, and resorcinol-formaldehyde oligomers coreacted with flavonoid units of the tannin. The last ones constitute a high proportion of the adhesive resin. Furthermore, their proportion is highest at the minimum phenolic reactivity around pH 4.     

Review of potable water biofilms in engineered systems

Abstract

Microbial biofilm formation on pipe walls has been shown to cause serious problems in potable water systems, including corrosion and the provision of sites for pathogenic bacterial development. The potential health threat associated with biofilms in potable water systems is discussed. An emerging problem is developing within the water sector with respect to the virulence of opportunistic bacterial pathogens which are, as well as being part of the normal planktonic heterotrophic bacterial population, readily isolated as sessile populations removed from pipes transporting potable water. Essentially only the bacteria in biofilms of potable water systems are multiplying and, owing to sloughing as a result of water shear, these constitute one of the main causes of deterioration of the microbiological quality of potable water systems, which could constitute a public health issue.     

我国粮油及其加工产品标准体系的现状与对策

本文综述了我国粮油及其加工产品标准体系的现状 ,包括我国粮油及其加工产品标准体系建设的历程和体系标准状况 ,并与国际性标准组织 (包括ISO、CAC)和主要发达国家 (美国、日本、英国、法国、德国 )进行分析比较 ,提出了今后我国粮油及其加工产品标准体系的发展对策     

Direct adhesion measurements of pharmaceutical particles to gelatin capsule surfaces

Scanning probe microscopy (SPM) was used to measure directly the adhesion of individual lactose particles to the surface of gelatin capsules employed in dry powder inhalant drug delivery systems. In this study, SPM shows that gelatin capsule surfaces with high surface heterogeneity and high-contrast friction exhibit high adhesion and that gelatin capsule surfaces with low surface heterogeneity and low-contrast friction exhibit low adhesion. The adhesion of lactose particles to gelatin capsules was also determined by measuring the retention of lactose particles in the capsules. The adhesion trend obtained with individual lactose particles using the colloidal probe technique agrees with the macroscopic retention results. The adhesion appears to be proportional to the particle size for homogeneous capsule surfaces. In dry powder inhalation products, the Lifshitz-van der Waals forces and acid-base interactions appear to be the principal forces contributing to particle-surface adhesion. The physicochemical nature of the capsule surface seems to dictate the spatial variation of adhesion across the surface. The SPM results clearly show that the surface physicochemical properties depend on the gelatin and mold release agent utilized in the manufacture of gelatin capsules. One of the practical implications of this study is that extraneous surface contamination of gelatin capsules by chemical processing aids such as mold release agents appears to be a key factor affecting the respirable fraction in dry powder inhalation products.