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51.
S. N. Fisher A. M. Guénault R. P. Haley G. R. Pickett G. N. Plenderleith P. Skyba 《Journal of Low Temperature Physics》1998,113(5-6):651-659
We present preliminary measurements of the dynamics of a moving A-B phase interface in superfluid
3
He at temperatures below 0.2T
c
We initially stabilise the interface at low temperatures with a shaped magnetic field. We can then move the interface in a controlled manner by applying small additional time-dependent fields. The interface is created inside a quasiparticle radiator consisting of a cylindrical chamber in weak thermal contact with the refrigerant. Vibrating wire resonators inside the radiator allow us to monitor the temperature of the superfluid and to infer the heat generated by the interface motion. When we oscillate the interface at low frequencies, we measure spectacular oscillatory swings of the liquid temperature arising from the enormous change in the low lying density of states as the volume of the A-phase superfluid is alternately compressed and expanded. We have also observed hysteresis in the transition as a function of magnetic field. In particular, we observe a small history-dependent super-magnetisation of the B-phase prior to A-phase nucleation in the experimental chamber. When the system is in the metastable super-magnetised state we are able to observe a higher nucleation probability of the A-phase when the cryostat is exposed to neutrons. 相似文献
52.
This paper presents a class library dedicated to digital image processing which provides resources for essential digital image processing operations. Besides its practical value, the class library is used to teach both object-oriented software engineering methodology and digital image processing. The resulting module can be accessed from independent specialized applications through its public interface while its implementation details are perfectly encapsulated. First of all it is used as the inner part of an integrated environment designed for students and researchers in the field of digital image processing. This software component was built aiming for both portability and extendibility. It contains attributes and methods that allow for a wide range of digital image processing algorithms: point and geometric operations; filter, edge detection, segmentation and texture operations; and fast Fourier transforms, discrete cosine transforms, and wavelet and Gabor transformations. All these can be used for image enhancement, restoration, compression, analysis, and synthesis 相似文献
53.
N. N. Aleshina L. M. Fisher V. N. Lisitskii N. A. Nigel'skii O. L. Polushenko I. F. Voloshin S. A. Zver'kov 《Journal of Superconductivity》1996,9(5):535-538
The microstructure and phase constitution of bulk textured YBCO samples prepared by the modified MTG method in the longitudinal temperature gradient have been investigated. We found the existence of an unusual phase between stacked platelets. Microanalysis shows that this phase may be characterized as Y-143. This phase forms ellipsoid-like particles with a typical size about 0.05–2 which can play the role of effective pinning centers. The reason for the phase formation is discussed. We assume that this phase exists commonly in melt-textured samples prepared in the temperature field gradient. 相似文献
54.
G Mozes P Gloviczki SS Menawat DR Fisher SW Carmichael A Kadar 《Canadian Metallurgical Quarterly》1996,24(5):800-808
PURPOSE: This study was undertaken to define the surgical anatomy of the medial perforating veins (PVs) of the leg and to provide information on how to gain access to all medial PVs from the superficial posterior compartment during a subfascial endoscopic procedure. METHODS: The venous anatomy of 40 limbs (from 23 cadavers) were studied. Medial PVs located between the ankle and the tibial tuberosity were dissected. None of the subjects had pathologic evidence of venous disease. Each PV's type (direct or indirect), size (< 1 mm, 1 to 2 mm, > 2 mm), location (distances from ankle [D1], and tibia [D2]), and accessibility from the superficial posterior compartment were recorded. RESULTS: Five hundred fifty-two PVs were identified (mean, 13.8; range, 7 to 22). Two hundred eighty-seven PVs (52%) directly connected the superficial with the deep systems, 228 (41%) were indirect muscle perforators, and 37 PVs (7%) were undetermined. One hundred thirty-seven PVs (25%) were > 2 mm. Sixty-three percent of PVs were accessible from the superficial posterior compartment. In the distal half of the leg, two groups of direct PVs could be identified (Cockett II: D1, 7 to 9 cm; Cockett III: D1, 10 to 12 cm). In the proximal half of the leg, paratibial direct PVs (D2 < or = 1 cm) were found clustered in three groups (D1, 18 to 22 cm; D1, 23 to 27 cm; D1, 28 to 32 cm). CONCLUSIONS: Our study confirmed the presence of the Cockett II and III PVs and three groups of proximal paratibial PVs, including the "24-cm" perforators. Two thirds of the medial direct PVs are accessible for endoscopic division from the superficial posterior compartment. To divide paratibial PVs, however, incision of the paratibial deep fascia is frequently required. 相似文献
55.
56.
The feasibility of general task systems with precedence constraints on multiprocessor platforms 总被引:1,自引:1,他引:0
Feasibility analysis determines (prior to system execution-time) whether a specified collection of hard-real-time jobs executed
on a processing platform can meet all deadlines. In this paper, we derive near-optimal sufficient tests for determining whether
a given collection of jobs can feasibly meet all deadlines upon a specified multiprocessor platform assuming job migration
is permitted. The collection of jobs may contain precedence constraints upon the order of execution of these jobs. The derived
tests are general enough to be applied even when the collection of jobs is incompletely specified. We discuss the applicability
of these tests to the scheduling of collections of jobs that are generated by systems of recurrent real-time tasks. We also
show that our feasibility conditions may be used to obtain global-EDF schedulability conditions.
相似文献
Sanjoy BaruahEmail: |
57.
58.
Christiane Jasmin Reinert‐Weiss Holger Baur Sheikh Abdullah Al Nusayer David Duhme Norbert Frühauf 《Journal of the Society for Information Display》2017,25(2):90-97
Conventional adaptive driving beam headlamps are limited in achieving still higher quantities of switchable pixels by the number of LEDs and movable elements needed. In this paper, it is shown that by integrating an active matrix liquid crystal display module, it is possible to realize fully adaptive high‐resolution headlights without mechanical elements and a finite number of LED with 30 k switchable pixels. 相似文献
59.
Outsourcing continues to capture the attention of researchers as more companies move to outsourcing models as part of their
business practice. Two areas frequently researched and reported in the literature are the reasons why a company decides to
outsource, and outsourcing success factors. This paper describes an in-depth, longitudinal case study that explores both the
reasons why the company decided to outsource and factors that impact on success. The paper describes how Alpha, a very large
Australian communications company, approached outsourcing and how its approach matured over a period of 9 years. The paper
concludes that although a number of reasons are proposed for a company's decision to outsource, lowering costs was the predominant
driver in this case. We also describe other factors identified as important for outsourcing success such as how contracts
are implemented, the type of outsourcing partner arrangement, and outsourcing vendor capabilities.
相似文献
Robert JacobsEmail: |
60.
Galvin AL Tipper JL Jennings LM Stone MH Jin ZM Ingham E Fisher I 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2007,221(1):1-10
Crosslinked ultra-high molecular weight polyethylene (UHMWPE) has been developed and introduced into clinical practice in order to reduce wear in the hip. Zero wear of highly crosslinked UHMWPE in vitro has been reported by some groups using lubricants with high concentrations of serum proteins in hip simulators. In contrast, some clinical studies have reported finite wear rates. The aim of this study was to compare the wear rates, wear surfaces, and wear debris produced by UHMWPE with different levels of crosslinking in a hip joint simulator, with lower, more physiologically relevant concentrations of protein in the lubricant. The UHMWPEs were tested in the Leeds ProSim hip joint simulator against cobalt-chromium (CoCr) femoral heads. The wear particles were isolated and imaged using a field emission gun scanning electron microscope (FEGSEM) at high resolution. The highly crosslinked UHMWPEs had significantly lower wear volumes than the non-crosslinked UHMWPEs. No significant difference was found in the percentage number and percentage volume of the particles in different size ranges from any of the materials. They had similar values of specific biological activity. The functional biological activity (FBA), which takes into account the wear volume and specific biological activity, showed that the highly crosslinked UHMWPEs had lower FBAs due to their lower wear volume. 相似文献