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101.
Chan Min Yoo Jongmin Joo Sang Hoon Lee Youngtak Ko Sang-Bum Chi Hyung Jeek Kim Inah Seo Kiseong Hyeong 《Ocean Science Journal》2018,53(2):381-394
A high level of confidence in resource data is a key prerequisite for conducting a reliable economic feasibility study in deep water seafloor mining. However, the acquisition of accurate resource data is difficult when employing traditional point-sampling methods to assess the resource potential of polymetallic nodules, given the vast size of the survey area and high spatial variability in nodule distribution. In this study, we analyzed high-resolution acoustic backscatter intensity images to estimate nodule abundance and increase confidence levels in nodule abundance data. We operated a 120 kHz deep-towed sidescan sonar (DSL-120) system (1×1 m resolution) across a 75 km2 representative area in the Korean Exploration Area for polymetallic nodules in the Northeastern Equatorial Pacific. A deep-towed camera system was also run along two tracks in the same area to estimate the abundance of polymetallic nodules on the seafloor. Backscatter data were classified into four facies based on intensity. The facies with the weakest and strongest backscatter intensities occurred in areas of high slope gradient and basement outcrops, respectively. The backscatter intensities of the two other facies correlated well with the nodule abundances estimated from still-camera images. A linear fit between backscatter intensity and mean nodule abundance for 10 zones in the study area yielded an excellent correlation (r2 = 0.97). This allowed us to compile a map of polymetallic nodule abundance that shows greater resolution than a map derived from the extrapolation of point-sampling data. Our preliminary analyses indicate that it is possible to greatly increase the confidence level of nodule resource data if the relationship between backscatter intensity and nodule abundance is reliably established. This approach has another key advantage over point sampling and image analyses in that detailed maps of mining obstacles along the seafloor are produced when acquiring data on the abundance of polymetallic nodules. The key limitation of this work is a poor correlation between nodule coverage, as observed from photographs, and nodule abundance. Significant additional ground truth sampling using well located box cores should be completed to determine whether or not there is a real correlation between the backscatter and abundance. 相似文献
102.
Lee Hyun Koo Lee Chan Hee Yoo Bong Cheal Lee Jong Chang Department of Geology Chungnam National University Taejon Korea 《中国地质大学学报(英文版)》2000,11(2)
INTRODUCTIONThe Janggun mine,Republic of Korea,is located in thesoutheast of the Seoul,about latitude36°5 1′N and longitude12 9°0 4′E. In this mine area is situated the Bonghwa m ineral-ized zone of the Taebaegsan mining district,Korea.The geo-logic setting of the region was described as the Samgeum riQuadrangle(Kim et al.,196 2 ) .The general and local geolo-gy near the mine area have been studied by L ee (196 7) ,Hwang and Reedman(1975 ) .This mine consists of four min-eral de… 相似文献
103.
L. . Popovi E. G. Mediavilla E. Bon D. Ili G. Richter 《Astronomische Nachrichten》2004,325(5):376-379
We present here new spectroscopic observations of Mrk 1040 and LEDA 212995 (Mrk 1040 companion) obtained with the Isaac Newton Telescope (INT). The intensity ratios and widths for the narrow emission lines found in LEDA 212995 are typical of H II regions. The red‐shift (0.0169 ± 0.00015) of the object derived from these emission lines is very close to the red‐shift of Mrk 1040 (z = 0.01665). The weak narrow and broad absorption lines were detected in the Hα wavelength band of LEDA 212995 spectra. These absorptions indicate that the companion might be at least partly obscured by Mrk 1040. Using this and previous observations we discuss the possible physical relationship between these two galaxies. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
104.
Marcelo Leandro BUENO Vanessa Leite REZENDE Luiza Fonseca A.DE PAULA Joo Augusto Alves MEIRA-NETO José Roberto Rodrigues PINTO Andreza Viana NERI Vanessa PONTARA 《山地科学学报》2021,(5):1192-1207
The campo rupestre sensu lato is a vegetation type that occurs in South American mountains, supports a distinctive flora characterized by high rates of endemism, high herbaceous species richness and often-neglected but also species-rich of the arboreal stratum. We aimed to investigate how environmental factors and elevation are associated with the distribution and diversity of woody species in different rupestrian vegetation types across South America. Using a database of 2,049 woody species from 185 sites across four vegetation types within the campo rupestre, we assessed how the vegetation types were grouped according to their floristic composition and number of shared indicator species, as well as by using different beta diversity indices. The most important variables from a set of 27 variables(e.g. altitude, geo-edaphic and climatic) explaining species distribution were identified using redundancy analysis(RDA) and variation partitioning methods. The distribution of vegetation types was related to both environmental and spatial fractions, with a set of 17 variables retained(e.g. rockiness, grass cover and temperature seasonality as the most important variables). There was an association between the floristic composition of each vegetation type and the elevation range. Although the identified vegetation types are floristically related, they are distinguished by exclusive and habitat-specialist woody species. This uniqueness of vegetation types should be considered in terms of complementarity for the conservation of campos rupestres. 相似文献
105.
地震属性可以由多种地震子波的特征来定义。并且根据不同的标准分类。选择叠前地震数据特征可提供丰富的诸如偏移和方向的资料,此次研究中,我们将限制叠后地震数据以提取地震属性,叠后地震数据可以通过子波特征和瞬时特征来分类。 相似文献
106.
We present MLD variability over the North Pacific Ocean in a global ocean general circulation model and impacts of three different vertical mixing schemes on it, based on statistical measures (annual mean difference, root-mean-square difference and correlation coefficient). The constant vertical mixing scheme tends to underestimate MLD over the whole basin. The Pacanowski-Philander scheme tends to overestimate MLD (> 20 m) in the mid- to high latitude during summer, implying that vertical mixing in the mid- to high latitude may not be represented properly by simple internal mixing mechanisms such as stratification or vertical shear of horizontal velocity. On the other hand, the new vertical mixing scheme (Noh et al. 2002) gives the most consistent MLD and its seasonal and spatial variability when compared with observation. These results suggest that parameterization of vertical mixing has significant effects on simulation of the seasonal and spatial variability of MLD over the North Pacific Ocean. 相似文献
107.
108.
Yu Jihyun Kang Min Joo Kim Yun Jae Park Mi-Jeong Lim Jae Kyu Noh Choong Hwan Kang Sung Gyun Lee Hyun Sook Lee Jung-Hyun Kwon Kae Kyoung 《Ocean Science Journal》2021,56(3):297-306
Ocean Science Journal - The Korean rockfish, Sebastes schlegeli, is most commonly farmed in sea cages along the coast of Korea; however, detailed information on intestinal microbiota regarding this... 相似文献
109.
Y.-H. Kim S.-B. Ryoo J.-J. Baik I.-S. Park H.-J. Koo J.-C. Nam 《Theoretical and Applied Climatology》2008,92(3-4):239-248
Summary Changes in local thermal environment associated with the restoration of an inner-city stream in Seoul, Korea, are investigated
using observational data. The stream, called the Cheonggye stream, which had been hidden and covered with cement/asphalt for
46 years, runs 5.8 km eastward through a central region of Seoul. Intensive observations were made in the stream area for
a number of summertime periods before, during, and after the stream restoration to detect the effects of the stream on local
environment and to quantify them. It is estimated that after the stream restoration the near-surface temperature averaged
over the stream area dropped by 0.4 °C, with the largest local temperature drop being 0.9 °C. However, it cannot be stated
that this 0.4 °C temperature drop is due entirely to the stream effect only, because synoptic-scale and local-scale weather
conditions during the two periods were inevitably not identical. The stream effect on air temperature is also evident in the
temperature distribution along a street traversing the stream. In the daytime after the stream restoration, the sensible heat
flux was greatly reduced and the ratio of sensible heat flux to net radiative flux dramatically decreased. These first-time
results of the restored-stream effects on urban thermal environment could contribute to the scientific basis of urban planning
which aims to make a large city comfortable to live in and nature- and environment-friendly.
Authors’ addresses: Yeon-Hee Kim, Il-Soo Park, Hae-Jung Koo, and Jae-Cheol Nam, Meteorological Research Institute, Korea Meteorological
Administration, Seoul 156-720, Korea; Sang-Boom Ryoo, Suwon Meteorological Office, Korea Meteorological Administration, Suwon
441-856, Korea; Jong-Jin Baik, School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, Korea 相似文献
110.
Jeong Joo Bong Jung Hoi-Soo Lee Jun-Ho Park Kyung Kyu Kim Seok Yun Woo Han Jun 《Ocean Science Journal》2022,57(3):451-466
Ocean Science Journal - Dadae Beach located in the Nakdong River estuary has been continuously evolving as the result of natural and anthropogenetic activities. Due to the geographic... 相似文献