人胚肺细胞转化试验及其对甲基丙烯酸环氧丙酯致癌性的研究

建立了人胚肺细胞（２ＢＳ）转化系统，并对甲基丙烯酸环氧丙酯（ＧＭＡ）的潜在致癌性进行了研究。结果表明，转化试验结果良好，试验方法可行。利用２ＢＳ细胞检测ＧＭＡ的转化能力，再次证明了ＧＭＡ对细胞有很强的致转化作用。     

The ambivalence of ridesharing

Ridesharing is quite a popular topic of discussion among transport authority personnel. It is perceived to be a viable alternative to classical modes of transportation, and receives a great deal of political support from transport planners. However, not much objective information is available on ridesharing behaviors. We use travel survey data to study the evolution of the ridesharing market in an urban area. Our study is based on data from four large-scale OD surveys conducted in the Greater Montreal Area (1987, 1993, 1998 and 2003). In the latest survey conducted in Montreal, car passengers were asked to identify the driver who gave them the opportunity to travel in this way. Their answers were classified according to the type of driver; for instance, a member of their household, a neighbor or a co-worker. We use this information to calibrate a model matching car passengers and car drivers belonging to the same household. This will be referred to as IHHR (intra-household ridesharing). Preliminary results reveal that approximately 70% of all trips made by car passengers are the result of IHHR. Furthermore, around 15% of those trips are questionable, in that they were exclusively generated for another individual’s purposes, consequently generating an additional trip for the journey back home. Moreover, this percentage increased over time. Objective data regarding ridesharing and its evolution in an urban area will undoubtedly help decision makers gain a clearer profile of this means of travel and help to realign attitudes on the issue.

Improving the toughness of high strength GMA welds

The propertied of high strength GMA welds are controlled by bead size, in particular the weld metal microstructure which is controlled by weld cooling rate. Shielding gas composition is known to be important as regards the protection of the molten weld pool from atmospheric contamination. However the role of the shielding gas composition in developing weld metal toughness is less well documented. This paper attempts to identify those characteristics in the deposition of a weld which contribute to improved toughness in high strength steel welds.