• Economic and Environmental Geology
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• v.54 no.5
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• pp.581-594
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• 2021

In 2020, about 132 million m³ of aggregate was produced in Korea. Of the total domestic aggregates produced in 2020, about 33.3 % was sand and about 66.7% was gravel. It estimated that of the 132 million m³ of aggregates in Korea in 2020, about 52% was produced by screening crushed aggregate, by 36% by forest aggregate, 3% by land aggregate, 5.6% by sea aggregate and 2.5% by washing each other, and 0.4% by river aggregate. This indicates that screening crushed aggregate and forest aggregate are the main producers of domestic aggregates. Leading producing metropolitan cities were Gyeonggi-do, Gyeongsangnam-do, Chungcheongbuk-do, Gangwon-do, Chungcheongnam-do, Incheon in order decreasing volume, which together accounted for about 72.4% of total product. In 2020, aggregates were produced in 153 cities, about 67% of the 231 cities of Korea, 38 local governments have developed aggregates of more than 1 million m³, and the combined production of the 38 cities accounted for about 65% of national total. This means that the aggregate extraction trend of local governments is becoming larger and more concentrated. In 2020, at 153 local governments, a total of 889 operations produced aggregates with 420 operations by permission, 469 operations by declaration. A review of production by size of operation indicated that about 17 million m³ (12.8% of the total aggregate) was produced by 14 operations reporting production of more than 1 million m³. In about 420 operations, the maximum period of permit is 32 years to at least 2 months. When the remaining period of permit is taken into account, only about 55% of active operations can be developed the aggregate after 2021. In order to maintain the permitted aggregate volume by 2020 level, it will be necessary to obtain an extension permit or find new operation sites for at least 200 or more operations.

• Korean Journal of Medicinal Crop Science
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• v.4 no.3
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• pp.241-246
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• 1996

This Experiment was conducted to know effect of cutting times and nitrogen split application rates on shoot and root-related characters of Atractylodes japonica. The cutting time was forced on none, once and twice along with three levels of nitrogen split application, all basic 50 -30 -20% and 40 -30 -30%. The plant height declined with increased cutting time and dry matter weight was increased with nitrogen split application under none and once cutting. Average yield of cutted shoot as edible wild plant was 257kg/10a at once cutting condition, but twice cutting condition was little and unfavorable to use edible wild plant because shoot was coarse. Yield 0 dry rhizome was the highest at once shoot cutting und­er 50 -30 -20% nitrogen split application by 471kg/10a.Especially, culture of Atractylodes japonka needed once shoot cutting one the 10th-30th of May.

• Water for future
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• v.29 no.2
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• pp.129-141
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• 1996

A procedure for computing total suspended sediment load is presented based on a single point-integrated sample, a power velocity distribution, and Laursen's sediment concentration distribution equation. The procedure was tested with field data from the Rio Grande River. Computed concentrations agreed well with depth-integrated measurements corrected for unmeasured load using nominal values of $\beta$, $\kappa$ and w. Even better agreement was obtained when site-specific data were used to define the x and z exponents of the velocity and concentration distributions. The difference between total suspended load computed using a single measurement and this procedure and conventional computations based on depthintegrated measurements is well within sampling error. There are major advantages in estimating total suspended load using a single time-integrated suspended-sediment point sample. Less field time is required; sampling costs are greatly reduced; and sampling can be more frequent and better timed to measure the changing sediment load. Single-point sampling makes automatic sampling procedures more feasible.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.87-101
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• 2023

The purpose of this study identifies the production of aggregate every year, and is to understand the supply and demend prospects. In 2021, the total of 135 million m³ of of aggregates was produced in Korea, a slightly increase from the total production of 2020. Of these, about 47 million m³ of sand and about 88 million m³ of gravel were produced. About 46% of total quantity of aggregates were produced with permission and the rest were aggregates produced after declaration. It estimated that of the 135 million m³ of aggregates in Korea in 2020, about 49.6% was produced by screening crushed aggregate, by 36.8% by forest aggregate, 2.6% by land aggregate, 6.8% by sea aggregate and 2.6% by washing each other, and 0.2% by river aggregate. This indicates that screening crushed aggregate and forest aggregate are the main product as in 2021. Leading producing metropolitan governments were Gyeonggi-do, Chungcheongnam-do, Incheon, Gyeongsangnam-do, Chungcheongbuk-do, Gangwon-do, Jeollanam-do, Gyeongsangbuk-do in order decreasing volume. In 2021, aggregates were produced in 148 local governments, and The 10 leading producing local governments were, in descending order of volume, Hwaseong, Ongjin, Paju, Pocheon, Gwangju, Youngin, Cheongju, Gimhae, Anseong, west EEZ. The combined production of the 10 leading local governments accounted for 30% of the national total, and. 47 local governments have produced aggregates of more than 1 million m³ each other. In 148 local governments that produced aggregate, a total of 805 active operations produced aggregate with 372 operations by river, land and forest aggregate, 433 operations by selective crushed and washing aggregate.

• The Journal of the Korean dental association
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• v.45 no.10 s.461
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• pp.609-618
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• 2007

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.4
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• pp.37-44
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• 2011

This paper was development of surface contamination automatic smear sampling for measuring radioactive contamination in radiation controlled area of nuclear facility. In indirect method a smear paper are used manually. Activity on the smear paper is affected by varying the pressures applied, by the smearing time, by the difference of ares sampled during smearing. By means of these there are erroneous. In the future the apparatus will be developed as a portable apparatus measuring smear activity automatically by adding radiation detection instrument.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.1
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• pp.12-17
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• 2002

This study identified the physiological characteristics of Alnus firma seedlings collected from air polluted industrial complex of Yeosu area with inoculation of nitrogen-fixing nodule. A. firma individuals resistant or sensitive to air pollution stress at the study area were selected. Seeds of the individuals were sown in a pot and inoculated with the nodules collected at the same area about 3 weeks after germination. To compare the inoculation effects, photosynthesis was measured among the A. firma seedlings under 12 inoculation combinations of seed sources and nodule sources. Photosynthetic activities of seedlings from resistant mother trees were obviously higher than those from sensitive mother trees. In general, the seedlings inoculated with nodule of sensitive trees, showed a worse physiological trend on every combination. In this study, inoculation effect was less important factor than seed sources to photosynthetic activities of A. firma. This physiological characteristic seemed to be determined by seed sources rather than nodule sources.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.681-686
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• 2005

The purpose of this study was to analyze the chemical component of Camellia japonica L. according to picking time. Leaves of Camellia japonica L. were picked in April and May,2003. Free sugars (fructose, glucose and sucrose) and organic acids (citric acid, tartaric acid, succinic acid, acetic acid) were present in the Camellia japonica L. leaf. The contents of total free sugars and organic acids increased as picking time was delayed. The major components of free amino acids were aspartic acid, glutamic acid and histidine, and those of total amino acids were histidine and alanine. The contents of total free amino acids and total amino acids were decreased as picking time was delayed, while the ratio of essential amino acids to the total amino acids increased. The amount of minerals (P, Ca, K, Na and Fe), chlorophyll and total polyphenol increased as picking time was delayed.

• Korean Journal of Plant Resources
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• v.18 no.2
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• pp.279-284
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• 2005

The study was conducted to investigate the correlation and regression analysis between the factors - diameter, hight and crown width - and collection amount of Rhus lacquer by the sex of Rhus verniciflua. The relationship between the diameter and the collection amount of the lacquer by the sex of the lacquer tree indicated that, for both of the male and the female, the lacquer amount was likely to increase as the diameter got larger. In general, the male trees tended towards the higher amount of the lacquer than the female. The relationship between the crown width and the collection amount of the lacquer by the sex showed little difference. As the crown became wider, however, the lacquer amount showed the increasing trend. The regression analysis by the sex of the tree indicated that the major factors of the female had larger influence on the lacquer amount than those of the male. The no differences of statistical significance were found among the diameter, the height, the crown width, and the lacquer amount.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.41-46
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• 1992

To perform a long-term ambient sampling study at a residential site, an air sampler was constructed to collect 24-hour integrated air samples suitable for the volatile organic compounds (VOCs) analysis. It includes an esthetically acceptance due to proximity to homes, as fell as providing the required sampling specifications. The VOCs sampler accomodates four 5/8 "stainless steel(SS) traps packed with adsorbent(Tenax) and is capable of four flow rates in the range of 5 to 50 cc/min. Sintered metal filters(10 micrometer) were directly connected to the inlet of the trap adapters. Additional specifications include: 1) constructed of organically inert materials, 2) weatherproof, 3) battery operated, 4) collecting of VOCs at a breathing zone level, and 5) quiet operation with micro diaphragm pumps wrapped by the sponge. The pump/battery system was separated from the sampling shelter. Sound levels measured for this system were below permissible sound levels (NJDEP) at a residential site. The sampler has been successfully operated at both ground level in a residential area and on the roof of a one story elementary school.hool.