扭带管内油的受迫对流换热实验

以30~#透平油为工质,对在光管内插入三种不同扭率扭带的受迫流动的冷、热态流阻及换热性能进行了实验。实验的雷诺数为200～1150,普朗特数为320～590,实验结果表明:在本实验范围内,插有不同扭率的全长连续扭带管的换热系数为光管的1.7～2.6倍,而阻力系数为光管的3～7.5倍;且扭率的大小对扭带的流阻与换热影响较大。另外,还对间断扭带管内油的受迫对流换热进行了实验。     

超声弯曲工具头的动态特性仿真与实验研究

牙种植超声工具利用弯曲工具头能够制备异型种植窝孔,为了研究工具头弯曲角度对位移响应的影响,利用有限 元软件Abaqus对弯曲工具头进行动态仿真,得到不同弯曲角度工具头的位移响应,并通过实验验证有限元分析结果。验 证实验表明,有限元分析结果与实验结果基本保持一致,为具有弯曲工具头的牙种植超声工具的设计提供了方法和依据。     

Mental Models in Risk Assessment: Informing People About Drugs

One way to communicate about the risks of drugs is through the use of package inserts. The problems associated with this medium of informing patients have been investigated by several researchers who found that people require information about drugs they are using, including extensive risk information, and that they are willing to take this information into account in their usage of drugs. But empirical results also show that people easily misinterpret the information given. A conceptual framework is proposed that might be used for better understanding the cognitive processes involved in such a type of risk assessment and communication. It is based on the idea that people develop, through experience, a mental model of how a drug works, which effects it might produce, that contraindications have to be considered, etc. This mental model is "run" when a specific package insert has been read and a specific question arises such as, for example, whether certain symptoms can be explained as normal or whether they require special attention and action. We argue that the mental model approach offers a useful perspective for examining how people understand package inserts, and consequently for improving their content and design. The approach promises to be equally useful for other aspects of risk analysis that are dependent upon human judgment and decision making, e.g., threat diagnosis and human reliability analysis.