Observation of quasi-periodic pulsations in the solar flare SF 900610     

O. V. Terekhov  A. V. Shevchenko  A. G. Kuz’min  S. Yu. Sazonov  R. A. Sunyaev  N. Lund 《Astronomy Letters》2002,28(6):397-400

A quasi-periodic component was found at the maximum of the X-ray light curve for the June 10, 1990 solar flare detected by the Granat observatory. The pulsation period was 143.2±0.8 s. The intensity of the pulsing component is not constant; the maximum amplitude of the pulsations is ～5% of the total flare intensity. An analysis of the data showed the characteristic size of the magnetic loop responsible for these pulsations to be ～(1–3)×10¹⁰ cm.  相似文献   

Direct-Drive Inertial Confinement Fusion Implosions on Omega     

S. P. Regan  T. C. Sangster  D. D. Meyerhofer  K. Anderson  R. Betti  T. R. Boehly  T. J. B. Collins  R. S. Craxton  J. A. Delettrez  R. Epstein  O. V. Gotchev  V. Yu. Glebov  V. N. Goncharov  D. R. Harding  P. A. Jaanimagi  J. P. Knauer  S. J. Loucks  L. D. Lund  J. A. Marozas  F. J. Marshall  R. L. Mccrory  P. W. Mckenty  S. F. B. Morse  P. B. Radha  W. Seka  S. Skupsky  H. Sawada  V. A. Smalyuk  J. M. Soures  C. Stoeckl  B. Yaakobi  J. A. Frenje  C. K. Li  R. D. Petrasso  F. H. SÉguin 《Astrophysics and Space Science》2005,298(1-2):227-233

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Erratum to “High-pressure metamorphism and deep-crustal seismicity: evidence from contemporaneous formation of pseudotachylytes and eclogite facies coronas” [Tectonophysics 372 (2003) 59–83]     

Mats G Lund  Hkon Austrheim 《Tectonophysics》2004,379(1-4):257-258

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Thin superficial layer and lateral heterogeneities in southern Sweden using short-period Rayleigh-wave dispersion     

Kjell Åström  Carl-Erik Lund 《Geophysical Journal International》1994,118(1):231-244

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Gamma-burst studies using long-duration balloon flights in the Arctic     

Niels Lund 《Astrophysics and Space Science》1981,75(1):145-151

A new detector for accurate localization of the cosmic gamma-burst sources is presented. The detector is intended for satellite applications, but balloon flights will be used in the development phase. The advantages and limitations of Arctic balloon flights are discussed based on a trial flight in August 1979.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts, held at Toulouse, France, 26–29 November, 1979.  相似文献   

Reflection measurements along the EGT POLAR-profile, northern Baltic Shield     

C-E. Lund  P. Heikkinen 《Geophysical Journal International》1987,89(1):361-364

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Adapting California’s water management to climate change   总被引：1，自引：0，他引：1  

Ellen Hanak  Jay R. Lund 《Climatic change》2012,111(1):17-44

California faces significant water management challenges from climate change, affecting water supply, aquatic ecosystems, and flood risks. Fortunately, the state also possesses adaptation tools and institutional capabilities that can limit vulnerability to changing conditions. Water supply managers have begun using underground storage, water transfers, conservation, recycling, and desalination to meet changing demands. These same tools are promising options for responding to a wide range of climate changes. Likewise, many staples of flood management—including reservoir operations, levees, bypasses, insurance, and land-use regulation—are available for the challenges of increased floods. Yet actions are also needed to improve response capacity. For water supply, a central issue is the management of the Sacramento-San Joaquin Delta, where new conveyance, habitat investments, and regulations are needed to sustain water supplies and protect endangered fish species. For flood management, among the least-examined aspects of water management with climate change, needed reforms include forward-looking reservoir operation planning and floodplain mapping, less restrictive rules for raising local funds, and improved public information on flood risks. For water quality, an urgent priority is better science. Although local agencies are central players, adaptation will require strong-willed state leadership to shape institutions, incentives, and regulations capable of responding to change. Federal cooperation often will be essential.  相似文献   

Identification of Cu and Ni indicator plants from mineralised locations in Botswana     

Bonang B.M. Nkoane  Gerald M. Sawula  Grethe Wibetoe  Walter Lund 《Journal of Geochemical Exploration》2005,86(3):130-142

Plant species that accumulate high levels of metals in proportion to the metal content in the soil are of considerable interest in biogeochemical and biogeobotanical prospecting. This study was aimed at investigating copper and nickel accumulation in the plants Helichrysum candolleanum and Blepharis diversispina, to assess their potential use as mineral indicators in biogeochemical prospecting. Soils and plants were collected from copper–nickel mineralised areas in Botswana. Analyses of the soils and the respective plant parts (roots, stem, leaves and flowers) were carried out using ultrasonic slurry sampling electrothermal atomic absorption spectrometry (ETAAS), which allowed rapid determination of copper and nickel in small amounts of the samples.The metal concentration in the soil was in the range ≈ 40 μg/g–4% (w/w) for Cu and ≈ 60 μg/g–0.3% (w/w) for Ni. The concentration ranges of the elements in the plant parts were ≈ 6 μg/g–0.2% Cu and ≈ 3–210 μg/g Ni. At high soil metal content (greater than 2.5% (w/w) Cu and 0.1% (w/w) Ni), high levels of both nickel and copper were found in the shoots (leaves and flowers) of H. candolleanum. Concentrations as high as 0.2% (w/w) Cu were found in the leaves and flowers of H. candolleanum, indicating hyperaccumulation for this plant. For B. diversispina, the metal concentrations did not exceed 100 μg/g for any plant part, for both metals. Both plant species tolerate high concentrations of metals and should therefore be categorized as metallophytes. In order to evaluate metal translocation from the soil to the shoots, metal leaf transfer coefficients (ratio of metal concentration in the leaf to metal concentration in the soil) were calculated. Our data suggest that the two plant species have different metal uptake and transport mechanisms, which needs to be investigated further. The present work also suggests that H. candolleanum may be used as a copper/nickel indicator plant in biogeochemical or biogeobotanical prospecting.  相似文献   

A study of focusing telescopes for soft gamma rays     

Niels Lund 《Experimental Astronomy》1992,2(5):259-273

A study is presented on the feasibility of using Bragg diffraction from crystals to focus soft gamma-rays in the energy range up to 2 MeV. For astrophysics this band contains several very interesting gamma-ray lines from novae, supernovae and X- and gamma-ray transients.The study concludes that, in the energy range between 300 and 1300 keV, a Bragg-telescope with a focal length of about 50 meters could achieve a sensitivity for point sources which is between 5 and 10 times better than that currently expected for the ESA/NASA INTEGRAL-mission/1/. In addition, the angular resolution of the Bragg telescope would also be an order of magnitude better. Despite the large physical dimensions of the telescope, its feasibility does not seem out of reach. The requirements do not go appreciably beyond those of other scientific projects which have been studied and found technically feasible by ESA and NASA /2, 3/. The Bragg-telescope therefore may become the logical next step in soft gamma-ray astronomy following a sensitive survey project like INTEGRAL.  相似文献   

The fine structure of the lower lithosphere underneath the Blue Road profile in northern Scandinavia     

C.-E. Lund 《Tectonophysics》1979,56(1-2)

On the basis of DSS data from the recordings of compressional and shear waves made during the Blue Road shootings in 1972, velocity—depth models for the lower lithosphere are presented. A lid with a velocity of 8.32 km/s was found underneath the Mohorovic̆ić discontinuity. An upper-mantle fine structure consisting of several high- and low-velocity zones was derived. At a depth of 96 km, a P-velocity of 8.5 km/s was reached.A minimum shear-wave velocity of 4.70 km/s has been determined for the uppermost part of the mantle underneath the Mohorovičić discontinuity. This velocity allows a shear low-velocity zone of a few tens of kilometers in the uppermost post of the mantle.  相似文献