CORROSION RESISTANCE OF INTERFERENCE FILM ON STAINLESS STEEL     

张经磊  侯保荣 《中国海洋湖沼学报》1997,15(4):363-368

IwrRODUcrlONStainlessstalhasbeenusedwidelyasbuildingrnateria1,especiallyasdecoratingrnate-rialinbuildings.Ordinarystainlesssteehasonlyonemonot0noussilverywhitCcolourwhichsomeimesdoesnotrnatchwithitSsurmundingenvironment.lnordert0improveitSdereratingperfonnaneeandexpanditsuse,muchresearchhasbeenconductedsincethe4O'st0trytoformabright,uniform,highcorrosi0nandwearresistantco1ourfilmonastainlesssteesurface.Duringtheeariystage,anirnmersionedhodwasused,i.e.inimrs-ingthestainlesssteelinahots0luti…  相似文献   

Late Weichselian glacial maximum on Andøya, North Norway     

JOKOB J. MØLLER  TOR K. DANIELSEN  ARNE FJALSTAD 《Boreas: An International Journal of Quaternary Research》1992,21(1):1-13

Morphological, seismic and lithostratigraphic investigations of a moraine deposit at Bleik (the Bleik moraine), northern Andøya, show short-distance transported till overlying long-distance transported predominantly glaciofluvial ice-marginal deposits. Consolidated glaciomarine sediments from a core at present sea-level, c . 400 m distally to the moraine complex, contain 31 species of foraminifera, among which Cassidulina reniforme, Islandiella helenae and Trifarina fluens dominate, and fragments of the molluscs Mya truncata and Astarte sp. and the echinoid Strongylocentrotus sp. Amino acid analyses of the foraminifera Cibicides lobatulus and the mollusc Mya truncata indicate ages between 22,000 and 16,000 BP. Radiocarbon dating of fragments of Mya truncata from the upper part of the core gave an age of 17,940 ± 245 BP, while a dating of unidentified shell fragments from the lower part gave an infinite age (>40,000 BP). The sediment was probably disturbed by icebergs beyond the end moraine zone, and the radiocarbon and amino acid dating of Mya truncata therefore represent a maximum age for this process. This new evidence indicates two phases with a higher relative sea-level than at present at Bleik, c . 18,000 and >40,000 BP. The Bleik moraine probably represents the early Late Weichselian glacial maximum ( c . 22,000 BP), while the underlying deglaciation deposit and associated beach-ridge (Bruvollen) is of pre-Late Weichselian age. Moraine ridges 3–4 km to the south of Bleik probably indicate advances of local glaciers between 22,000 and 18,000 BP.  相似文献   

Isolation of resonance in acoustic backscatter from elastic targetsusing adaptive estimation schemes     

Azimi-Sadjadi  M.R. Wilbur  J. Dobeck  G.J. 《Oceanic Engineering, IEEE Journal of》1995,20(4):346-353

It has been shown that at certain frequencies the acoustic backscatter from elastic targets exhibits certain resonance behavior which closely relates to the physical properties of the target such as dimension, thickness, and composition. The purpose of this paper is to develop an automated approach for identifying the presence of resonance in the acoustic backscatter from an unknown underwater target by isolating the resonance part from the specular contribution. An adaptive transversal filter structure is used to estimate the specular part of the backscatter and consequently the error signal would provide an estimate of the resonance part. An important aspect of this scheme lies in the fact that it does not require an underlying model for the elastic return. The adaptation rule is based upon fast recursive least squares (RLS) learning. The approach taken in this paper is general in the sense that it can be applied to targets of unknown geometry and thickness and, further, does not require any a priori information about the target and/or the environment. Test results on acoustic data are presented which indicate the effectiveness of the proposed approach  相似文献   

Boundary Conditions and Efficient Solution Algorithms For the Potential Function Formulation of the 3-D Viscous Flow Equations     

G. A. Houseman 《Geophysical Journal International》1990,100(1):33-38

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Palaeointensity In the Pelagic Realm: Marine Sediment Data Compared With Archaeomagnetic and Lake Sediment Records     

C. G. Constable  L. Tauxe† 《Geophysical Journal International》1987,90(1):43-59

Summary. Four box cores collected from the Ontong—Java plateau during the Eurydice expedition have been used to make relative geomagnetic palaeo-intensity measurements. Rock magnetic measurements on the sediments show that they are characterized by a uniform magnetic mineralogy, and that they are suitable for relative intensity estimates. These are obtained by normalizing the NRM by an ARM imparted in a low DC bias field. the palaeoceanographic event known as the preservation spike is used to establish a crude time-scale for the record so that it may be compared with other data from the same region, and also with global palaeointensity estimates. the marine sediment data are quite similar to Australian intensity data from lake sediments and archaeomagnetic sources, but as might be expected exhibit some obvious differences from the global record.  相似文献   

Collisionless analogs of Riemann S ellipsoids with halo     

M. G. Abramyan 《Astrophysics》1986,25(2):563-569

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The MPE X-ray test facility PANTER: Calibration of hard X-ray (15–50 kev) optics     

M. J. Freyberg  H. Bräuninger  W. Burkert  G. D. Hartner  O. Citterio  F. Mazzoleni  G. Pareschi  D. Spiga  S. Romaine  P. Gorenstein  B. D. Ramsey 《Experimental Astronomy》2005,20(1-3):405-412

The Max-Planck-Institut für extraterrestrische Physik (MPE) in Garching, Germany, uses its large X-ray beam line facility PANTER for testing X-ray astronomical instrumentation. A number of telescopes, gratings, filters, and detectors, e.g. for astronomical satellite missions like Exosat, ROSAT, Chandra (LETG), BeppoSAX, SOHO (CDS), XMM-Newton, ABRIXAS, Swift (XRT), have been successfully calibrated in the soft X-ray energy range (< 15keV). Moreover, measurements with mirror test samples for new missions like ROSITA and XEUS have been carried out at PANTER. Here we report on an extension of the energy range, enabling calibrations of hard X-ray optics over the energy range 15–50 keV. Several future X-ray astronomy missions (e.g., Simbol-X, Constellation-X, XEUS) have been proposed, which make use of hard X-ray optics based on multilayer coatings. Such optics are currently being developed by the Osservatorio Astronomico di Brera (OAB), Milano, Italy, and the Harvard-Smithsonian Center for Astrophysics (CfA), Cambridge, MA, USA. These optics have been tested at the PANTER facility with a broad energy band beam (up to 50 keV) using the XMM-Newton EPIC-pn flight spare CCD camera with its good intrinsic energy resolution, and also with monochromatic X-rays between C-K (0.277 keV) and Cu-Kα (8.04 keV). PACS: 95.55.Ka, 95.55.Aq, 41 50.+h, 07.85.Fv  相似文献   

Book reviews     

Howard  R. F.  van den Oord  G. H. J.  Švestka  Z. 《Solar physics》1996,169(1):225-227

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Minimum norm quadratic estimation of components of spatial covariance     

K. V. Mardia 《Mathematical Geology》1986,18(2):267

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Asteroid families: evidence of ageing of the proper elements     

A. Dell'Oro  G. Bigongiari  A. Cellino 《Icarus》2004,169(2):341-356

In recent times it has been emphasized that the present kinematical structures of asteroid families should be evolved with respect to the original post-impact situations, according to numerical simulations performed taking into account also the previously neglected Yarkovsky effect. In this paper we show that also a “classical” approach based on an analysis of the current kinematical properties of families leads to conclude that the distributions of proper eccentricities and semimajor axes of family members exhibit evidence of an evolution. The importance of this approach is that it yields a fully independent and quantitative estimate of an evolutionary spreading of the proper elements. In particular, we find that the original post-impact families had to be on the average about twice more compact than the families we observe now, when considering family members down to about 5 km in size. This result can be used in future analyses to derive estimates of the ages of different families, and to better constrain the typical values of the ejection velocities of the fragments in family-forming events.  相似文献