聚酰胺原料生产技术的新进展

阐述了聚酰胺原料生产技术的一些新进展，包括环己烯法制环己醇、丁二烯法制己二酸、氨肟化法制环己酮和以己二腈为原料制己内酰胺。     

Rotation-invariant discrimination between almost similar objects

A modified circular harmonic filter may be used for the rotation-invariant discrimination of a target from another object which contains the same pattern as the target. The method is illustrated by the experimental rotation-invariant detection of the letter F in the presence of the letter E.     

Survey on production quality of electrodialysis reversal and reverse osmosis on municipal wastewater desalination

Water shortage has become an emerging environmental issue. Reclamation of the effluent from municipal wastewater treatment plant (WWTP) is feasible for meeting the growth of water requirement from industries. In this study, the results of a pilot-plant setting in Futian wastewater treatment plant (Taichung, Taiwan) were presented. Two processes, sand filter - ultrafiltration - reverse osmosis (SF-UF-RO) and sand filter - electrodialysis reversal (SF-EDR), were operated in parallel to evaluate their stability and filtrate quality. It has been noticed that EDR could accept inflow with worse quality and thus required less pretreatment compared with RO. During the operation, EDR required more frequent chemical cleaning (every 3 weeks) than RO did (every 3 months). For the filtrate quality, the desalination efficiency of SF-EDR ranged from 75 to 80% in continuous operation mode, while the conductivity ranged from 100 to 120 μS/cm, with turbidity at 0.8 NTU and total organic carbon at 1.3 mg/L. SF-EDR was less efficient in desalinating the multivalent ions than SF-UF-RO was. However for the monovalent ions, the performances of the two processes were similar to each other. Noticeably, total trihalomethanes in SF-EDR filtrate was lower than that of SF-UF-RO, probably because the polarization effects formed on the concentrated side of the EDR membrane were not significant. At the end of this study, cost analysis was also conducted to compare the capital requirement of building a full-scale wastewater reclamation plant using the two processes. The results showed that using SF-EDR may cost less than using SF-UF-RO, if the users were to accept the filtrate quality of SF-EDR.     

A syntactic approach to seismic pattern recognition

The nearest-neighbor decision rule for syntactic patterns is applied to seismic pattern classification. Each pattern is represented by a string. The string-to-string distance is used as a similarity measure. Another method using finite-state grammars inferred from the training samples and error-correcting parsers is also implemented. Both methods show equal recognition accuracy; however, the nearest-neighbor rule is much faster in computation speed. The classification results of real earthquake/explosion data are presented.     

注浆工程的主要发展方向

在复杂的水文地质条件下(如有裂隙的、孔隙的和含水的岩石),矿山井筒、水平和倾斜巷道施工时,对含水岩石广泛采用注浆方法,以便在巷道周围形成防渗帷幕。对于这种帷幕的主要要求,一是在巷道施工与生产期间具有优质的和经济的防水层,二是完成注浆工程的时间要短。使用注浆方法建造防渗帷幕的时间是比较长的(在含水岩石区段,要占掘进井筒全部时间的30～50%),但是可加快掘进速度,通常可超过定额50%,这是由于高质量