偶氮胂（Ⅲ）显色离子交换剂相光度吸收法测定海水中UⅥ）     

Nakas.  T 岳启建 《国外铀金地质》1993,10(2):182-187

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昆士兰芒特艾萨同构造期铜矿化的发育和定位的构造控制     

Bell  T.H 李上森 《国外前寒武纪地质》1989,(2):36-44

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苏联社会经济地理学的发展途径——根据《苏联地理学会第七次代表大会总结》     

H.T.阿加福诺夫  王荣来 《地理科学进展》1983,2(4):21-24

地理学力求通过综合途径研究国土、自然资源利用以及生产力的发展与配置问题。这门科学的实质旨在以具体的资料表明作为统一体的矿藏、土壤、森林和水的自然条件及其资源,全面地把握开发自然资源和发展生产力区域综合体的途径。  相似文献   

Identification and characterization of a new degradation product of Irgarol-1051 in mercuric chloride-catalyzed hydrolysis reaction and in coastal waters     

Lam KH  Lam MH  Lam PK  Qian T  Cai Z  Yu H  Cheung RY 《Marine pollution bulletin》2004,49(4):361-367

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Effects of oil spill on seawater infiltration and macrobenthic community in tidal flats   总被引：1，自引：0，他引：1  

Chung IY  Cho KJ  Hiraoka K  Mukai T  Nishijima W  Takimoto K  Okada M 《Marine pollution bulletin》2004,49(11-12):959-963

Tidal flat ecosystem simulators are used to clarify the effects of stranded fuel oil on tidal flat ecosystems. Results show that oil spills increase the periphyton on sediment by decreasing the predation stress caused by deposit feeders. About a month after an oil spill, the total population density of the macrobenthos recovered. The oxidation-reduction potential in the surface sediment drops to a negative value after the oil spill, and the anaerobic condition throughout the sediment seems to be responsible for the decrease in the population density of the macrobenthos. The infiltration volume of seawater into the oil-stranded sediment decreases to a third of that without the oil spill. The recovery of infiltration volume after about a month coincides with the recovery of the population density of the macrobenthos. This result suggests that the macrobenthic population is highly dependent on the infiltration of seawater.  相似文献   

Detection of Polarized Millimeter and Submillimeter Emission from Sagittarius A*     

Aitken DK  Greaves J  Chrysostomou A  Jenness T  Holland W  Hough JH  Pierce-Price D  Richer J 《The Astrophysical journal》2000,534(2):L173-L176

We report the detection of linear polarization from Sgr A* at 750, 850, 1350, and 2000 μm which confirms the contribution of synchrotron radiation. From the lack of polarization at longer wavelengths, it appears to arise in the millimeter/submillimeter excess. There are large position angle changes between the millimeter and submillimeter results, and these are discussed in terms of a polarized dust contribution in the submillimeter and various synchrotron models. In the model that best explains the data, the synchrotron radiation from the excess is self-absorbed in the millimeter region and becomes optically thin in the submillimeter. This implies that the excess arises in an extremely compact source of approximately 2 Schwarzschild radii.  相似文献   

First Mass-resolved Measurement of High-Energy Cosmic-Ray Antiprotons     

Bergström D  Boezio M  Carlson P  Francke T  Grinstein S  Khalchukov F  Suffert M  Hof M  Kremer J  Menn W  Simon M  Stephens SA  Ambriola ML  Bellotti R  Cafagna F  Ciacio F  Circella M  De Marzo C  Finetti N  Papini P  Piccardi S  Spillantini P  Bartalucci S  Ricci M  Casolino M  De Pascale MP  Morselli A  Picozza P  Sparvoli R  Bonvicini V  Schiavon P  Vacchi A  Zampa N  Mitchell JW  Ormes JF  Streitmatter RE  Bravar U  Stochaj SJ 《The Astrophysical journal》2000,534(2):L177-L180

We report new results for the cosmic-ray antiproton-to-proton ratio from 3 to 50 GeV at the top of the atmosphere. These results represent the first measurements, on an event-by-event basis, of mass-resolved antiprotons above 18 GeV. The results were obtained with the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas-RICH (Ring-Imaging Cerenkov) counter and a silicon-tungsten imaging calorimeter. The RICH detector was the first ever flown that is capable of identifying charge-one particles at energies above 5 GeV. The spectrometer was flown on 1998 May 28-29 from Fort Sumner, New Mexico. The measured p&d1;/p ratio is in agreement with a pure secondary interstellar production.  相似文献   

Eigenvector 1: An Optimal Correlation Space for Active Galactic Nuclei     

Sulentic JW  Zwitter T  Marziani P  Dultzin-Hacyan D 《The Astrophysical journal》2000,536(1):L5-L9

We identify a correlation space involving optical and UV emission-line parameters as well as the soft X-ray spectral index that provides optimal discrimination between all principal classes of active galactic nuclei (AGNs). Most of the sources in our three high-quality data samples show a strong intercorrelation with narrow-line Seyfert 1 (NLSy1) galaxies and steep-spectrum radio galaxies occupying opposite extrema in the space. NLSy1 sources show a clear continuity with broader line sources, indicating that they are not a disjoint class of AGN as is sometimes suggested. We interpret the principal intercorrelation in the parameter space as being driven by the AGN luminosity-to-black hole mass ratio (L&solm0;M is proportional to the Eddington ratio). Source orientation no doubt also plays an important role, but it is not yet clear whether FWHM Hbeta or C iv lambda1549 line shift is the better indicator. We tentatively identify two radio-quiet populations: an almost pure radio-quiet population A, with FWHM相似文献   

A Twisted Flux Rope Model for Coronal Mass Ejections and Two-Ribbon Flares     

Amari T  Luciani JF  Mikic Z  Linker J 《The Astrophysical journal》2000,533(1):L49-L52

We present a new approach to the theory of large-scale solar eruptive phenomena such as coronal mass ejections and two-ribbon flares, in which twisted flux tubes play a crucial role. We show that it is possible to create a highly nonlinear three-dimensional force-free configuration consisting of a twisted magnetic flux rope representing the magnetic structure of a prominence (surrounded by an overlaying, almost potential, arcade) and exhibiting an S-shaped structure, as observed in soft X-ray sigmoid structures. We also show that this magnetic configuration cannot stay in equilibrium and that a considerable amount of magnetic energy is released during its disruption. Unlike most previous models, the amount of magnetic energy stored in the configuration prior to its disruption is so large that it may become comparable to the energy of the open field.  相似文献   

Young Red Spheroidal Galaxies in the Hubble Deep Fields: Evidence for a Truncated Initial Mass Function at approximately 2 M middle dot in circle and a Constant Space Density to z approximately 2     

Broadhurst T  Bouwens RJ 《The Astrophysical journal》2000,530(2):L53-L56

The optical-IR images of the northern and southern Hubble Deep Fields are used to measure the spectral and density evolution of early-type galaxies. The mean spectral energy distribution is found to evolve passively toward a mid-F star-dominated spectrum by z approximately 2, becoming more sharply peaked around the 4000 ? break. We demonstrate with realistic simulations that hotter elliptical galaxies would be readily visible if evolution progressed blueward and brightward at z>2, following a standard initial mass function (IMF). The color distributions are best fitted by a "red" IMF, deficient above approximately 2 M middle dot in circle and with a spread of formation in the range 1.51 results from a selection bias against distant red galaxies in the optical, where the flux is too weak for morphological classification, but is remedied with relatively modest IR exposures that reveal a roughly constant space density to z approximately 2, with 32 and 16 elliptical galaxies detected above and below z=1, respectively. We point out that the lack of high-mass star formation inferred here and the requirement of metals implicates cooling flows of preenriched gas in the creation of the stellar content of spheroidal galaxies. Deep-field X-ray images will be very helpful in examining this possibility.  相似文献