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181.
Observations of the total lunar eclipse were made at 3.4-mm wavelength (87.4 GHz) on March 24, 1978. Eclipsr cooling curves with the best S/N ratio among those published thus far were obtained for the three points (the mountain area near the crater of Hipparuchus, Sinus Medii, and Copernicus). Each of the curves can be decomposed into the three parts which apparently correspond to ingress, totality, and egress. The derived cooling rate and heating rate differ significantly at the three points. 相似文献
182.
Large amorphous aggregates (NUTA) observed in coastal areas after spring and autumn phytoplankton blooms and red tide outbreaks
were collected using NUTA traps which we devised. These particles become thickly attached to mooring ropes and/or fishing
nets.
The variation of the collection of materials by NUTA traps was about 23% in organic carbon and 25% in organic nitrogen (n=29).
The chemical nature and vertical distribution pattern of NUTA were significantly different from those of suspended particles
collected by water samplers. Since C/ATP and C/Chlα ratios in NUTA were very high compared with those of suspended particles, NUTA seems to consist of a small amount of phytoplankton
but much detritus. These values suggest that NUTA has characteristics intermediate between suspended particles and sinking
particles. The standing stock of NUTA was also estimated to be no more than 10% suspended particles from a calculation of
the trapping efficiency of the NUTA trap. 相似文献
183.
Masahiro Nagashima & Naoteru Gouda 《Monthly notices of the Royal Astronomical Society》1998,301(3):849-860
The effects of merging histories of proto-objects on the angular momentum distributions of the present-time dark matter haloes are analysed. An analytical approach to the analysis of the angular momentum distributions assumes that the haloes are initially homogeneous ellipsoids and that the growth of the angular momentum of the haloes halts at their maximum expansion time. However, the maximum expansion time cannot be determined uniquely, because in the hierarchical clustering scenario each progenitor, or subunit, of the halo has its own maximum expansion time. Therefore the merging history of the halo may be important in estimating its angular momentum. Using the merger tree model by Rodrigues &38; Thomas, which takes into account the spatial correlations of the density fluctuations, we have investigated the effects of the merging histories on the angular momentum distributions of dark matter haloes. It was found that the merger effects, that is, the effects of the inhomogeneity of the maximum expansion times of the progenitors which finally merge together into a halo, do not strongly affect the final angular momentum distributions, so that the homogeneous ellipsoid approximation happens to be good for the estimation of the angular momentum distribution of dark matter haloes. This is because the effect of the different directions of the angular momenta of the progenitors cancels out the effect of the inhomogeneity of the maximum expansion times of the progenitors. The contribution of the orbital angular momentum to the total angular momentum when two or more pre-existing haloes merge together was also investigated. It is shown that this contribution is more important than that of the angular momentum of diffuse accreting matter to the total angular momentum, especially when the mergers occur many times. 相似文献
184.
The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans’ bridges not retrofitted by column
jacketing. In this respect, this study represents results of fragility curve development for two (2) sample bridges typical
in southern California, strengthened for seismic retrofit by means of steel jacketing of bridge columns. Monte Carlo simulation
is performed to study nonlinear dynamic responses of the bridges before and after column retrofit. Fragility curves in this
study are represented by lognormal distribution functions with two parameters and developed as a function of PGA. The sixty
(60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agcncy (FEMA)
SAC (SEAOC-ATC-CUREe) steel project are used for the dynamic analysis of the bridges. The improvement in the fragility with
steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit. In this first
attempt to formulate the problem of fragility enhancement, the quantification is made by comparing the median values of the
fragility curves before and after the retrofit. Under the hypothesis that this quantification also applies to empirical fragility
curves developed on the basis of Northridge earthquake damage, the enhanced version of the empirical curves is developed for
the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.
Supported by: MCEER/FHWA under Contract No.DTFH 61-98-C-00094 and Caltrans under Contract No.59A0304 相似文献
185.
Shigeru Aoki Kazuo Shibuya Akihiro Masuyama Taku Ozawa Koichiro Doi 《Journal of Oceanography》2002,58(3):519-523
Global Positioning System (GPS) measurements of the vertical displacement of fast ice near Syowa Station, Antarctica, were
conducted between April and December 1998 to evaluate measurements of sea level variation derived with a conventional bottom
pressure gauge (BPG). The BPG-derived sea level revealed a seasonal variation of about 0.13 m, with a high in April–June and
a low in November–December. The GPS-derived sea level, combined with observed sea ice thickness, supported the BPG result,
with an RMS error of 0.007 m. Our result also demonstrates that GPS is a powerful technique for monitoring sea level variations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
186.
海洋底栖甲藻的浮游行为特征研究 总被引:2,自引:0,他引:2
研究了日本濑户内海屋岛湾沙质海滩底栖甲藻中具有底栖-浮游兼性行为的种类及其浮游行为特征。发现具有游游兼性特征的有8种,分别是Amphidinium carterae,A.klebsii,A.herdmanae,Gymnodinium sp1,G.pyrenoidosum,Peridinium quinquecorne,Prorocentrum emarginatum和Pror.sp1,几乎全是该潮间带底栖甲藻的优势种,占水样中甲藻种数的11.6%,个体数占海水样品中甲藻总个体密度的0-51.3%,具有明显的季节性,当这些种类在沉积物样品中数量较少时,在海水样品中就极少出现,具有随潮汐变化的行为特征。研究表明这些种类是真底栖种,浮游生活只是其兼性行为特征,是长期进化和对潮间带特殊环境适应的结果,本文还探讨了底栖甲藻的浮游习性及其与内湾近岩赤潮的关系和可能产生的影响。 相似文献
187.
Satoru Kojima Kazuhiro Tsukada Shigeru Otoh Satoshi Yamakita Masayuki Ehiro Cheikhna Dia Galina Leontievna Kirillova Vladimir Akimovich Dymovich Lyudmila Petrovna Eichwald 《Island Arc》2008,17(4):502-516
The Anyui Metamorphic Complex (AMC) of Cretaceous age is composed of metachert, schist, gneiss, migmatite and ultramafic rocks, and forms a dome structure within the northernmost part of the Jurassic accretionary complex of the Samarka terrane. The two adjacent geological units are bounded by a fault, but the gradual changes of grain size and crystallinity index of quartz in chert and metachert of the Samarka terrane and the AMC, together with the gradual lithological change, indicate that at least parts of the AMC are metamorphic equivalents of the Samarka rocks. Radiolarian fossils from siliceous mudstone of the Samarka terrane indicates Tithonian age (uppermost Jurassic), and hence, form a slightly later accretion. This signifies that the accretionary complex in the study area is one of the youngest tectonostratigraphic units of the Samarka terrane. The relationship between the Samarka terrane and AMC, as well as their ages and lithologies, are similar to those of the Tamba–Mino–Ashio terrane and Ryoke Metamorphic Complex in southwest Japan. In both areas the lower (younger) part of the Jurassic accretionary complexes were intruded and metamorphosed by Late Cretaceous granitic magma. Crustal development of the Pacific‐type orogen has been achieved by the cycle of: (i) accretion of oceanic materials and turbidites derived from the continent; and (ii) granitic intrusion by the next subduction and accretion events, accompanied by formation of high T/P metamorphic complexes. 相似文献
188.
189.
Hiroo Kagami Masaki Yuhara Shigeru Iizumi Yoshiaki Tainosho Masaaki Owada Yasuo Ikeda
Osamu Okano Shuji Ochi Yoshikazu Hayama and Terukazu Nureki 《Island Arc》2000,9(1):3-20
Osamu Okano Shuji Ochi Yoshikazu Hayama and Terukazu Nureki 《Island Arc》2000,9(1):3-20
Abstract The Ryoke Belt is one of the important terranes in the South‐west Japan Arc (SJA). It consists mainly of late Cretaceous granitoid rocks, meta‐sedimentary rocks (Jurassic accretionary complexes) and mafic rocks (gabbros, metadiabases; late Permian–early Jurassic). Initial ?Sr (+ 25– + 59) and ?Nd (? 2.1–?5.9) values of the metadiabases cannot be explained by crustal contamination but reflect the values of the source material. These values coincide with those of island arc basalt (IAB), active continental margin basalt (ACMB) and continental flood basalt (CFB). Spiderdiagrams and trace element chemistries of the metadiabases have CFB‐signature, rather than those of either IAB or ACMB. The Sr–Nd isotope data, trace element and rare earth element chemistries of the metadiabases indicate that they result from partial melting of continental‐type lithospheric mantle. Mafic granulite xenoliths in middle Miocene volcanic rocks distributed throughout the Ryoke Belt were probably derived from relatively deep crust. Their geochemical and Sr–Nd isotopic characteristics are similar to the metadiabases. This suggests that rocks, equivalent geochemically to the metadiabases, must be widely distributed at relatively deep crustal levels beneath a part of the Ryoke Belt. The geochemical and isotopic features of the metadiabases and mafic granulites from the Ryoke Belt are quite different from those of mafic rocks from other terranes in the SJA. These results imply that the Ryoke mafic rocks (metadiabase, mafic granulite) were not transported from other terranes by crustal movement but formed in situ. Sr–Nd isotopic features of late Cretaceous granitoid rocks occurring in the western part of the Japanese Islands are coincident with those of the Ryoke mafic rocks. Such an isotopic relation between these two rocks suggests that a continental‐type lithosphere is widely represented beneath the western part of the Japanese Islands. 相似文献
190.
Roger Brewer Josh Nagashima Mark Rigby Martin Schmidt Harry O'Neill 《Ground Water Monitoring & Remediation》2014,34(4):79-92
Generic indoor air:subslab soil gas attenuation factors (SSAFs) are important for rapid screening of potential vapor intrusion risks in buildings that overlie soil and groundwater contaminated with volatile chemicals. Insufficiently conservative SSAFs can allow high‐risk sites to be prematurely excluded from further investigation. Excessively conservative SSAFs can lead to costly, time‐consuming, and often inconclusive actions at an inordinate number of low‐risk sites. This paper reviews two of the most commonly used approaches to develop SSAFs: (1) comparison of paired, indoor air and subslab soil gas data in empirical databases and (2) comparison of estimated subslab vapor entry rates and indoor air exchange rates (IAERs). Potential error associated with databases includes interference from indoor and outdoor sources, reliance on data from basements, and seasonal variability. Heterogeneity in subsurface vapor plumes combined with uncertainty regarding vapor entry points calls into question the representativeness of limited subslab data and diminishes the technical defensibility of SSAFs extracted from databases. The use of reasonably conservative vapor entry rates and IAERs offers a more technically defensible approach for the development of generic SSAF values for screening. Consideration of seasonal variability in building leakage rates, air exchange rates, and interpolated vapor entry rates allows for the development of generic SSAFs at both local and regional scales. Limitations include applicability of the default IAERs and vapor entry rates to site‐specific vapor intrusion investigations and uncertainty regarding applicability of generic SSAFs to assess potential short‐term (e.g., intraday) variability of impacts to indoor air. 相似文献