5,451 research outputs found
Inversion formula for determining parameters of an astrometric binary
It is believed that some numerical technique must be employed for the
determination of the system parameters of a visual binary or a star with a
planet because the relevant equations are not only highly nonlinear but also
transcendental owing to the Kepler's equation. Such a common sense, however, is
not true; we discover an analytic inversion formula, in which the original
orbital parameters are expressed as elementary functions of the observable
quantities such as the location of four observed points and the time interval
between these points. The key thing is that we use the time interval but not
the time of each observation in order to avoid treating the Kepler's equation.
The present formula can be applied even in cases where the observations cover a
short arc of the orbit during less than one period. Thus the formula will be
useful in the future astrometric missions such as SIM, GAIA and JASMINE.Comment: 8 pages; accepted for publication in PAS
Pressure-dependent 13C chemical shifts in proteins: Origins and applications
Pressure-dependent (13)C chemical shifts have been measured for aliphatic carbons in barnase and Protein G. Up to 200 MPa (2 kbar), most shift changes are linear, demonstrating pressure-independent compressibilities. CH(3), CH(2) and CH carbon shifts change on average by +0.23, -0.09 and -0.18 ppm, respectively, due to a combination of bond shortening and changes in bond angles, the latter matching one explanation for the gamma-gauche effect. In addition, there is a residue-specific component, arising from both local compression and conformational change. To assess the relative magnitudes of these effects, residue-specific shift changes for protein G were converted into structural restraints and used to calculate the change in structure with pressure, using a genetic algorithm to convert shift changes into dihedral angle restraints. The results demonstrate that residual (13)C alpha shifts are dominated by dihedral angle changes and can be used to calculate structural change, whereas (13)C beta shifts retain significant dependence on local compression, making them less useful as structural restraints
AN AUCTION-BASED MARKETPLACE FOR NOTIFICATIONS DELIVERY
A notification delivery module is described that enables a computing system to selectively deliver notifications to a user. The notification delivery module may set a total budget (e.g., a total number of notifications a user may receive for a week) for the user based on prior notification delivery history. The notification delivery module may change (e.g., increase or decrease) the total budget for the user based on user history (e.g., volume and quality of the notifications that are delivered and interacted by the user). The notification delivery module may periodically (e.g., every 24-hour window) allocate a budget to every application provider, based on the application’s active user-installed base or daily/monthly active users (DAU/MAU) metrics related to the application, and may replenish the budget periodically (e.g., reset the budget weekly). Each notification may be assigned a bid price, which may be calculated based on one or more criteria including: user feedback (e.g., whether the user merely views the notification or interacts with the notification), time (e.g., desired time for delivering the notification), target platform (e.g., mobile, web, desktop), notification delivery mechanism (e.g., device or email), content (e.g., related or unrelated to the user’s interest), and overall quality (e.g., value to the application provider or to the user) of the notification. Notifications for a notification provider may be ranked based on the bid price. Higher-ranked notifications may be delivered to the user device prior to the lower-ranked notification until the budget for the particular notification provider runs out. When a delivered notification is dismissed before it is seen by the user, the notification delivery module may return the unused budget to the notification provider. The notification delivery module may also allow the user to set notifications to be delivered without any cost (e.g., free notifications). The notification delivery module may identify good opportunities to deliver notifications based on user activity and learn to avoid delivery of notifications at bad delivery times (e.g., during meetings or while the user is asleep). The notification delivery module may also allow exchange (e.g., sale or purchase) of budget between application providers based on an application’s current need
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京都大学0048新制・課程博士博士(医学)甲第21649号医博第4455号新制||医||1034(附属図書館)京都大学大学院医学研究科医学専攻(主査)教授 宮本 享, 教授 森田 智視, 教授 鈴木 実学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA
Finite element analysis of tube drawing process with diameter expansion
This paper presents a tube drawing process with diameter expansion for producing a thin-walled tube effectively. In this proposed process, the tube was flared by a plug pushing into the tube, and then the tube was expanded by drawing the plug in the tube axial direction with chucking the flared tube edge. Optimum plug shape, such as the plug half angle and the corner radius, was investigated by a series of analyses using the finite element method (FEM) for improving the forming limit and the dimension accuracy. At first, a friction coefficient was determined to 0.3 by a comparison of the flaring limit between the analysis and the experiment of the tube flaring. As a result of the analyses in the drawing with the diameter expansion, the forming limit was high when the plug half angle was set to 18~30°. The thickness reduction ratio increased with an increase in the expansion ratio and the plug half angle. In addition, the overshoot, which is a difference between the plug diameter and the tube inner diameter after the drawing, was prevented by using the plug with the corner radius of 20 mm
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