Effect of prior deformation on dimensional change and precipitation process in a Cu-1.8wt%Be-0.2wt%Co alloy aged at 320C

金沢大学理工研究域機械工学系The influence of prior cold work (90% reduction) on the length change and precipitation behaviour of a Cu-1.8wt%Be-0.2wt%Co alloy aged at 320C up to 350 h has been investigated. The alloy gradually expands to a maximum and then contracts during ageing. The maximum expansion is attributable to both the expansion due to the loss of Be solute atoms and the contraction due to precipitation of the [image omitted], I, m and \u27 phases. The subsequent contraction results from the decrease in amounts of the [image omitted] and m phases and the increase in amount of the \u27 phase. The new-found m phase, consisting of alternate Be and Cu matrix layers parallel to the matrix {001}, is body-centred monoclinic with a = b = 0.263 nm and c = 0.279 nm and = 83, and aligns with the matrix according to the Bain orientation relationship. The Guinier-Preston (GP) zone transforms continuously to the m or I phase via \u27\u27 and [image omitted]. The transformation from the GP zone to \u27 via \u27\u27, [image omitted] and I is retarded in comparison with that for the un-deformed alloy.全文公開20100

Effect of external stress on discontinuous precipitation in a Cu-2.1 wt % Be alloy

金沢大学理工研究域機械工学系The influence of an applied stress on discontinuous precipitation (DP) in a Cu-2.1 wt % Be alloy aged at 300 °C was examined. A compressive stress accelerates the growth of DP cells, which consist of lamellae of the precipitated γ phase and the solute-depleted α phase, but a tensile stress does not essentially change it. The cell growth rates along the loading direction under the compressive and tensile stress are identical to those along the direction perpendicular to the loading direction under the same stress. Both the compressive and tensile stresses have no influence on the incubation time to initiate DP. From measurements of the specimen length change and investigations of the distribution of γ variants in cells in a particular case, specific γ variants among crystallographically equivalent ones are found to be formed, depending on the sense of the applied stress. This result, together with the dependence of the cell growth rate on the sense of the applied stress, can be well understood through the interaction energy between the external stress and the misfit strains of discontinuous γ precipitates

Spatial-Importance-Based Computation Scheme for Real-Time Object Detection From 3D Sensor Data

Three-dimensional (3D) sensor networks using multiple light-detection-and-ranging (LIDAR) sensors are good for smart monitoring of spots, such as intersections, with high potential risk of road-traffic accidents. The image sensors must share the strictly limited computation capacity of an edge computer. To have the computation speeds required from real-time applications, the system must have a short computation delay while maintaining the quality of the output, e.g., the accuracy of the object detection. This paper proposes a spatial-importance-based computation scheme that can be implemented on an edge computer of image-sensor networks composed of 3D sensors. The scheme considers regions where objects exist as more likely to be ones of higher spatial importance. It processes point-cloud data from each region according to the spatial importance of that region. By prioritizing regions with high spatial importance, it shortens the computation delay involved in the object detection. A point-cloud dataset obtained by a moving car equipped with a LIDAR unit was used to numerically evaluate the proposed scheme. The results indicate that the scheme shortens the delay in object detection

"Valuing Variable Annuities" (in Japanese)

In this paper we propose a framework to evaluate variable annuities. We show that the invested capital to a variable annuity can be decomposed into: (i) the reserve money in the account, (ii) options, (iii) fees paid to the mutual fund companies, and (iv) margin accruing to the insurance company. The first two components comprise value to the insured, and the last two accrue to the supply side companies. This view provides a convenient method to double-check the computation of various components of value. We also show that death benefit option attached to the most popular variable annuities is a portfolio of European put options of differing maturities. Assuming that investment value follows a geometric Brownian motion, this component can be valued applying the Black-Scholes formula and using the "death rates statistics" published by the Ministry of Heath, Labour and Welfare. Options on the income benefit are also valued using the Black-Scholes formula.@Stepped-up death benefit is a form of look-back options, which we value using a trinomial lattice. We value some typical products assuming that a person purchases them at age 40 and at age 50. We then examine how various value components would change in response to the volatilities of the investment products, the length of the contract and so on.

Thinning minimization for forming aluminum beverage can end shells

Forming simulations of the can end shell have been implemented based on both of the axisymmetric model and three-dimensional models, for a better understanding of the forming process. The comparison shows that the simulation results agree reasonably well with the experimental observations of the actual forming process. The influence of the loads applied to tools, the clearance between tools, the shape of the tool profile and the position of tools have been investigated, based on the axisymmetric model to save computational time. The design optimization method based on the numerical simulations have been applied to search the optimum design points, in order to reduce the thinning subjected to the constraints of the geometric shape of the shell and the suppression of wrinkles. The optimization results show that the thinning can be improved up to 4% by optimizing the forming route, adjusting the clearance and the load, and modifying the tool shape. © 2010 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved

アカデミックライティングにおける「分かりにくさ」の要因は何か? : 意見文の分析を通じた一考察

学部レベルの留学生に必要なアカデミックジャパニーズに関して,ライティング能力の評価や測定に関する研究は,喫緊の課題である。本稿では,日本語非母語話者の作文をめぐって,大学教員を対象として行った評価調査の概要を報告する。また,その調査結果に基づき,日本語非母語話者である留学生によって執筆された意見文の分かりにくさの要因についての考察を行う。その結果として,「分かりにくさ」の一端を具体的に明らかにする。最後に,結論として,意見文においては,主張文とその根拠となる事実文の適切な構成がなされているか否かが,意見文全体への評価を決定付けていることを主張する。Research into the evaluation and measurement of writing ability in academic Japanese as required of international students at the bachelor\u27s level is a pressing issue. This report outlines evaluations conducted by university instructors on the written works of nonnative speakers of Japanese. In addition, based on the results of these evaluations, observations are presented concerning the factors that affect the difficulty of understanding opinion pieces written by foreign students whose mother tongue is not Japanese. As a result, one aspect of this difficulty will be clarified in detail. It is concluded that the overall evaluations of opinion pieces are determined by whether or not the thesis statement and its supporting evidence are structured properly or not