Bayesian inference in group judgment formulation and decision making using qualitative controlled feedback

Summary This paper considers the problem of making statistical inferences about group judgments and group decisions using Qualitative Controlled Feedback, from the Bayesian point of view. The qualitative controlled feedback procedure was first introduced by Press (1978), for a single question of interest. The procedure is first reviewed here including the extension of the model to the multiple question case. We develop a model for responses of the panel on each stage. Many questions are treated simultaneously and an autoregressive model is developed for explaining the responses of the group members as a function of the feedback. The errors are assumed to follow a matrix intraclass covariance structure. Marginal and conditional posterior distributions of the regression coefficient vector are found in both small and large samples. The broadly defined generic family of multidimensional Student-t-distribution is found to play a major role in the results.     

Single carbon nanotube transistor at GHz frequency

We report on microwave operation of top-gated single carbon nanotube transistors. From transmission measurements in the 0.1-1.6 GHz range, we deduce device transconductance gm and gate-nanotube capacitance Cg of micro- and nanometric devices. A large and frequency-independent gm approximately 20 microS is observed on short devices, which meets the best dc results. The capacitance per unit gate length of 60 aF/microm is typical of top gates on a conventional oxide with epsilon approximately 10. This value is a factor of 3-5 below the nanotube quantum capacitance which, according to recent simulations, favors high transit frequencies fT=gm/2piCg. For our smallest devices, we find a large fT approximately 50 GHz with no evidence of saturation in length dependence.     

Design through making: crafts knowledge as facilitator to collaborative new product development

Collaboration between manufacturers and craft makers is believed by many crafts theorists to offer new originality, insight and specialist expertise to design for production. In practice, however, there exists a discrepancy between this ideal and a reality of unreconcilable cultural and methodological differences. This paper documents and discusses such a collaboration as an example of best practice with implications for managers, educators, designers and craft makers. It identifies a new role for craft makers with the appropriate knowledge and experience to act as bridges within companies, facilitating the adoption of design methodologies appropriate to changing priorities in the manufacturing industries.     

Thermo-mechanical fatigue damage and failure of modern high performance diesel pistons

This study resulted from an engineering failure investigation related to diesel engine piston failures which occurred during a bench dynamometer engine durability test programme. The test programme aimed at evaluating the effects of various fuel types on the durability of fuel system components in passenger car diesel engines. A number of unexpected cylinder head, turbocharger and piston failures were experienced during the course of the test programme. This study focused on the cause of the piston failures experienced during these tests.Analyses of the fractured pistons revealed that thermo-mechanical fatigue initiation occurred as a result of primary silicon phase cracking and subsequent micro-crack formation due to excessive thermo-mechanical loading. Progressive formations of such micro-cracks lead to flaws that were of sufficient magnitude to initiate propagation by high cycle fatigue mechanisms.The investigation also revealed that the excessive thermo-mechanical piston loading was caused by over-fuelling and a combination of elevated and poorly controlled post intercooler air temperature. There was no evidence to suggest that the failures were related to the test fuel formulations.     

带液压制动器的多级行星齿轮减速器在新型特大型三辊卷板机？…

本文介绍一种新型齿轮箱一多级行星齿轮箱,和一般卷板机比较,它的驱动结构简单,这种齿轮箱易于制造、传动性能良好。     

基于柔性元结构的广义模块化产品族建模及其应用

根据广义模块化设计原理。对广义模块化产品族和产品平台作了整体规划，阐述了柔性模块、虚拟模块、元结构以及柔性元结构等概念，提出了以柔性元结构为基础构建广义模块化产品族的思想。以组合框架式液压机的应用为例，分析了柔性元结构的具体创建过程。实践证明，该方法可以有效加速产品的设计．     

Measurement of brain activity with bolus administration of contrast agent and gradient-echo MR imaging

This study was performed to measure changes in cerebral blood volume (CBV) associated with visual activation by use of bolus administration of contrast agent and conventional, clinically configured magnetic resonance (MR) hardware and software. Fast gradient-recalled acquisition in the steady state technique was used to study five healthy subjects during visual activation and a control dark state. MR images were obtained every 2.048 seconds for 2 minutes. A bolus of gadopentetate dimeglumine was injected during visual stimulation and darkness. Cine images produced from the series of rapid images clearly depicted arterial, capillary, and venous phases. Analysis of serial concentration maps derived from the rapid images revealed expected differences between the relative CBV of gray matter and that of white matter, as well as significantly increased relative CBV in calcarine cortex during visual activation versus the control state (mean increase, 15.24%; range, 6.41%-27.78%; P < .05). These results confirm those reported in echo-planar imaging studies and demonstrate that brain function can be assessed with the bolus method by means of MR imaging hardware and software with conventional clinical configurations.     

中国油气地质特点

中国油气地质条件无论在生、储、盖方面,还是在运、聚、保方面都有自己的特点.如陆相生油、多期生油,多种多样的储集岩体,复杂的储集岩性,明显的生储盖组合,油气的再次运移和运移距离不长,复式油气聚集带,以及较强的有机质变质作用等.这些特点的形成,是由于构造运动的多旋回性和印支、燕山运动波及中国大陆,致使海水基本退净所致.这些特点在各含油气盆地中都有不同程度的反映.