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排序方式: 共有888条查询结果,搜索用时 9 毫秒
91.
Tomas Selicky Matus Jurcik Barbora Mikolaskova Alexandra Pitelova Nina Mayerova Miroslava Kretova Michaela Osadska Jan Jurcik Roman Holic Lenka Kohutova Jana Bellova Zsigmond Benko Juraj Gregan Silvia Bagelova Polakova Peter Barath Lubos Cipak Ingrid Cipakova 《International journal of molecular sciences》2022,23(21)
92.
Tomas Bayer 《GeoInformatica》2016,20(2):241-284
This article presents three new methods (M5, M6, M7) for the estimation of an unknown map projection and its parameters. Such an analysis is beneficial and interesting for historic, old, or current maps without information about the map projection; it could improve their georeference. The location similarity approach takes into account the residuals on the corresponding features; the minimum is found using the non-linear least squares. For the shape similarity approach, the minimized objective function ? takes into account the spatial distribution of the features, together with the shapes of the meridians, parallels and other 0D-2D elements. Due to the non-convexity and discontinuity, its global minimum is determined using the global optimization, represented by the differential evolution. The constant values of projection φ k , λ k , φ 1, λ 0, and map constants R,ΔX,ΔY, α (in relation to which the methods are invariant) are estimated. All methods are compared and the results are presented for the synthetic data as well as for 8 early maps from the Map Collection of the Charles University and the David Rumsay Map Collection. The proposed algorithms have been implemented in the new version of the detectproj software. 相似文献
93.
94.
Designers of electronic equipment are faced with the contractual obligation of guaranteeing that their products will fulfil the specifications on life duration. Classically, empirical methods based on databases and handbooks are used and features such as Mean Time Between Failure (MTBF) are provided. This paper presents how to use Physics of Failure (PoF) tools and results in order to provide the customer with a reliability feature, called life margin, based on Cycles To Failure (CTF) figures. The method defines and computes a life margin for 99% of the population in the given environmental life conditions. This feature is used to evaluate the different technological possibilities and decide the best trade-off to satisfy the customer’s requirement on life duration. The method has been applied to a given board and a given application, where the component, which limits reliability, has been identified as being packaged in a Ball Grid Array (BGA) package. 相似文献
95.
Efficient collision detection for models deformed by morphing 总被引:4,自引:0,他引:4
Published online: 5 February 2003 相似文献
96.
How primary particles affect the fragmentation of particle composites using discrete element method simulation is described. Disk‐shaped composite particles consisting of large aggregate particles embedded in a matrix of smaller sand particles have been impacted against a solid surface at range of collision velocities. The results have been analyzed to determine whether the shapes of the aggregates in the mixture have an influence on the fragmentation of particle composites. It has been identified that the fracture depends on the aggregate shapes of the particle composites. Liberation degrees and particle size distributions have also been found to be controlled by the shape of the primary particles. Particle shapes have a remarkable influence on the fragmentation behavior of the specimen, especially at lower velocities. 相似文献
97.
The in vitro activity of Δ9- and Δ6-desaturases was determined in the microsomal fraction of C3H/S normal mouse liver, SS1K fast growing hepatoma, and SS1H slow growing hepatoma. These tumors are two different sublines of a spontaneous hepatoma transplanted in 1949 by J.W. Wilson, Brown University, Providence, R.I., into C3H/ST W: strain. The activity of the two enzymes showed a parallel decrease in the two studied hepatomas. These alterations could be attributed to a fundamental change in structure or function in the tumors. The fatty acid desaturase activity seems to be independent of cell division in malignant tissues. 相似文献
98.
Single crystals of so-called “FeYb2S4 spinel” were prepared and their crystal structure was solved. The cubic cell, space group Fd3m, has a lattice constant . From X-rays determinations, its content is (Fe0.76 Yb2.16 S4) × 8. Iron is divalent and ytterbium is trivalent. Ytterbium is in two series of octahedral sites, which are partially filled : 0.96 Yb and 0.04 ? on every 16d position, 0.12 Yb and 0.88 ? on every 16c position. Only 0.76 iron atom is in every 8a position of the spinel. 相似文献
99.
Essential fatty acid (EFA) deficient rats were injected intraportally with a solution of 1-14C-linoleic acid during a 1 min period. Livers were quickly frozen, pulverized, and the lipids extracted and fractioned by
thin layer chromatography. The incorporation of 1-14C-linoleic acid into liver lipids was measured. The results were compared with those previously obtained from normal rats.
No significant differences were observed in the total radioactivity recovered from lipid extracts. While the distribution
of radioactivity into the 1–2 diacylglycerol fraction remained unchanged in both groups of rats, in the EFA deficient rats
the 1-14C-linoleic acid incorporation was actually directed to the phospholipid fractions instead of to the triacylglycerol fractions
as was observed in the normal rats. 相似文献
100.