• Journal of Radiation Protection and Research
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• v.22 no.3
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• pp.219-226
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• 1997

Ultralow background gamma-ray measurement system was installed to measure and analyze gamma-rays emitted from environmental and swipe samples. The background reduction techniques applied on this system are the passive shielding to surround the HPGe detector, an active external anticosmic shield to shield cosmic-rays and the nitrogen gas supply to minimize the introduction of ubiquitous radon decay nuclei. The performance test result showed that the system background at energies between 50 keV and 2 MeV is reduced about $10^{-2}$ order and the MDA is so low as to be suitable for the environmental sample analysis. But it is appeared that the neutron produced by cosmic-ray increases the background at low energy region.

• Journal of the Korean Home Economics Association
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• v.36 no.5
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• pp.75-88
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• 1998

The purpose of this study is to investigate (1) the level of childrens' concern and behavior on the environmental preservation, (2) the influential factors related to the two dependent variables above mentioned. The subjects were 286 childrens, in October, 1997, in kwangju. The data obtained were analyzed by Mean, Person's correlation, Stepwise Regression and Path Analysis. The major findings were as follows: 1) The general tendency of the childrens' concern and behavior on the environmental preservation was over the average level. 2) According to the background variables(ie: environment information contracting time, family cohesion and adaptability, biospheric orientation, egoistic orientation), the childrens' concern on the environment was significantly different. 3) According to (1) the background variables(ie: environment information contracting time, family cohesion and adaptability, concern on the environment, biospheric orientation), (2) intermediated variable(ie: concern on the environment), the childrnes' behavior on the environmental preservation was significantly different. 4) The indirect variable of the positive influence for childrnds' behavior on the environment, environment information contracting time. The indirect variable of the negative influence for childrens' the environmental behavior was egoistic orientation.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.255-258
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• 2009

This study shows that the $Hg^0$ background concentration over the Yellow Sea was generally higher than those observed over other seas/oceans around the world. $Hg^0$ concentrations measured in the urban stomophere were significantly higher than the background concentration in China. Elevated $Hg^0$ concentrations at Deokjeok Island in Korea were attributed to long-range transport of mercury from high emission areas in China.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.23-32
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• 2013

Korean groundwater quality standards were established in 1994, and revised in 2003 and 2010. The substances for which standards have been developed are classified into two groups, general pollutants, 4, and specific pollutants, 15. The standards have been applied to household water use, agriculture, aquaculture, and industrial use. However, there is no systematic methodology for either selecting candidate substances or establishing groundwater standards. We investigated various derivation methodologies for groundwater standards used by the European Commission and 27 member states and compared their methods for determining threshold values. The European Commission presented to their member states groundwater standards for two substances and a list of required substances for derivation of threshold values along with the member states. Interestingly, they first considered national background levels and then considered other criteria for water protection, such as drinking water standards, environmental quality standards, and irrigation standards. We suggest that Korean background levels in groundwater should be included in the methodology for establishing groundwater quality standards. These results may be useful in developing a systematic methodology for establishing Korean groundwater quality standards.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.780-786
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• 2005

The biomass of the brown seaweed, Ecklonia, was used to remove Cr(VI) from wastewater. Previously, Cr(VI) was removed through its reduction to Cr(III) when brought into contact with the biomass. In this study, the effects of ionic strength, background electrolytes, and Cr(III), Ni(II), Zn(II), and Fe(III) on the Cr(VI) reduction were examined. An increased ionic strength inhibited the Cr(VI) reduction. The presence of other heavy metals, such as Cr(III), Ni(II), or Zn(II), only slightly affected the Cr(VI) reduction, while Fe(III) enhanced the reduction. Although the above various parameters could affect the reduction rate of Cr(VI) by Ecklonia biomass, these effects were relatively smaller than those of pH and temperature. In addition, the previously derived rate equation was found to be applicable over a range of ionic strengths and with different background electrolytes. In conclusion, Ecklonia, bioniass may be a good candidate as a biosorbent for the removal of Cr(VI) from wastewaters containing various other impurities, and scale-up to a practical process may be accomplished using the previously derived rate equation.

• Nuclear Engineering and Technology
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• v.34 no.6
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• pp.545-552
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• 2002

We developed an ultra low background gamma ray spectrometer particularly suitable for experiment which require lower detection limit. The background of a germanium spectrometer is suppressed by applying active and passive shielding technique at the same time. The active shielding devices consist of plastic scintillating plates of 50 mm thick and anti-coincidence electronic system. The shielding is made of 150 mm thick walls of very low activity lead,20 mm with activity of <10 Bq/kg and 130 mm with activity of <50 Bq/kg. The observed background count rates are 1.2 $s^{-1}$ and 0.36 $s^{-1}$ without and with the active shielding, respectively, overall the energy regions from 30 keV to 3 MeV The cosmic ray induced background is suppressed by a rate of 0.8 $s^{-1}$ at the present work. The detection efficiency curve necessary to obtain the radioactivity of environmental samples has been precisely determined on the energy regions from 80 to 2000 keV with a 10$^3$ ml marinelli beaker sample, consisting of the calibrated radionuclides $^{109}$ Cd, $^{57}$ CO, $^{139}$ Ce, $^{203}$ Hg, $^{113}$ Sn, $^{85}$Sr, $^{137}$ Cs, $^{60}$ Co and $^{88}$ Y. Virtues Of the method are demonstrated by measuring the activity of $^{137}$ Cs contained in the powdered milk.

• Ocean and Polar Research
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• v.44 no.4
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• pp.287-296
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• 2022

High-frequency (HF) radar measures sea surface currents from the radio waves transmitted and received by antenna on land. Since the data quality of HF radar measurements sensitively depend on the radio wave environment around antenna, Antenna Pattern Measurements (APM) plays an important role in evaluating the accuracy of measured surface currents. In this study, APM was performed by selecting the times when the background noise level around antenna was high and low, and radial data were generated by applying the ideal pattern and measured pattern. The measured antenna pattern for each case was verified with the current velocity data collected by drifters. The radial velocity to which the ideal pattern was applied was not affected by the background noise level around antenna. However, the radial velocity obtained with APM in the period of high background noise was significantly lower in quality than the radial velocity in a low noise environment. It is recomended that APM be carried out in consideration of the radio wave environment around antenna, and that the applied result be compared and verified with the current velocity measurements by drifters. If it is difficult to re-measure APM, we suggest using radial velocity in generating total vector with the ideal pattern through comparative verification, rather than poorly measured patterns, for better data quality.

• The Bulletin of The Korean Astronomical Society
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• v.25 no.2
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• pp.100-100
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• 2000

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.152-155
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• 2003

• The Bulletin of The Korean Astronomical Society
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• v.27 no.1
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• pp.59-59
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• 2002