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991.
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James K. Finch 《Journal of The Franklin Institute》1940,230(6):685-700
994.
Dynamical analysis of winter terrain park jumps 总被引:1,自引:1,他引:0
Jump features in winter terrain parks frequently pose a hazard to patrons and may represent a significant liability risk to
winter resorts. By performing a simple dynamic analysis of terrain park jumps, the relative risk to impact injuries for any
proposed jump design can be quantified thereby allowing terrain park designers to minimize the risk from this class of injury. 相似文献
995.
Understanding the role of shaft stiffness in the golf swing 总被引:3,自引:3,他引:0
Theoretically, shaft stiffness can alter shot distance by increasing clubhead speed or altering clubhead orientation at impact.
A 3D forward dynamics model of a golfer and flexible club simulated the downswing. A genetic algorithm optimized the coordination
of the model’s muscles (four torque generators) to maximize clubhead speed. The maximum torque output and maximum rate of
torque development from the torque generators were varied to simulate the swing of golfers that generate different clubhead
speeds. Four shafts of varying stiffness (flexible, regular, stiff, and completely rigid) were entered into these simulations
to examine the role that shaft flexibility had on clubhead speed and orientation at impact. Shaft stiffness was found to have
a meaningful effect only on clubhead orientation (dynamic loft and dynamic close) at impact. There was no evidence to support
the premise that matching the stiffness properties of the shaft with the golfer would improve clubhead speed. 相似文献
996.
This study analyzed the factor structure of the Wechsler Intelligence Scale for Children-Revised (WISC-R), the Peabody Picture Vocabulary Test (PPVT), and the Peabody Individual Achievement Test (PIAT) in a psychiatric sample that ranged in age from 6 to 16 years (mean age = 11.1 years; SD = 3.0). The resultant factor structure of this sample was compared with patterns reported on normal and learning-disabled children. The subjects were 329 children under inpatient and outpatient care who had been referred for emotional disturbances. The results were similar to previous factor analytic studies of the WISC-R and PIAT, showing four factors: Verbal Comprehension, Verbal Achievement, Perceptual Organization, and Number Facility. The implications for the interpretation of these tests in a psychiatric sample and the appropriateness of a maximum likelihood technique in analysis of psychometric data are discussed. 相似文献
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We use prices realized for Picasso prints at auctions worldwide, as well as the 100 prints that comprise his Vollard Suite,
to test the law of one price: the proposition that identical art objects sold contemporaneously should command the same price
regardless of the auction house or geographic region where the sale takes place. Picasso is the most prolific printmaker of
the twentieth century and, from 1977 to 2004, his prints appreciated in price significantly faster than the prints of modern
masters as a whole. We find that Picasso prints sold in the United States command higher prices than in Europe. However, prices
realized at Sotheby’s in New York are no longer higher than at Christie’s in New York, nor at Kornfeld than at other auction houses. We find evidence of “irrational exuberance”
in the transitory nature of the extraordinary prices realized for the Picasso prints included in the 1997 sale of the collection
of Victor and Sally Ganz at Christie’s in New York. More generally, we find substantial noise in auction outcomes, a result
well known to savvy auction goers.
相似文献
Pauline M. Shum (Corresponding author)Email: |