• Journal of the Korean Geographical Society
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• v.50 no.5
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• pp.505-514
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• 2015

This study analyzes a correlation between water content values and chemical index of alteration (CIA) for coarse sedimentary rocks of Mt. Cheonsaeng in Gumi-si, Kyeongsangbuk-do. Through measurement of various water values of 20 samples including water content rate, water absorption rate and equipment measuring we comparatively analyzed the values with CIA of the samples obtained by X-ray fluorescence. As a result of analysis water content rate and water absorption rate in a sedimentary rock are likely to be higher when matrix is psephitic and less compact. Furthermore the higher water content rate is, the higher CIA is due to increase of $SiO_2$ and $Al_2O_3$ and decrease of CaO and $Na_2O$ derived by chemical weathering of felspar. This correlation between water content rate and CIA represents a similar result with previous studies targeting granite.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1199-1205
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• 2001

There has been an increase in the public concern about possible health risks by electromagnetic exposure from mobile phones. Recently, several SAR measurement procedures have been proposed to demonstrate the compliance of mobile phone with safety limits. To determine the maximum localized SAR of a test mobile phone, the electric field distribution is measured in the head phantom with simulated tissue liquid using the probe The important parameters in SAR measurement are the E-field probe, the shape and size of phantom, the electrical parameters of simulated tissue liquid, and test position, etc. Therefore, in order to setup the measurement standard, the studies on these factors are required. In this paper, the effects of the maximum localized SAR on the test positions of mobile phones were analyzed by the numerical computation and the SAR measurement. From the results, the worst condition of commonly used positions was determined and the touch and tilted positions were adopted as test positions of the domestic SAR measurement standard.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.438-445
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• 2004

A radiotracer study was conducted to evaluate the influence of body size and temperature on the uptake rates of Cd, Se and Zn in the California mussel, Mytilus californianus. Uptake rates of Cd, Se and Zn were determined simultaneously with clearance of the mussels with 3 different size classes (0.07, 0.24 and 0.73 g flesh dry weight $individual^{-1})$ and at 4 different temperatures (3, 8, 13 and $21^\circ{C})$. The weight-specific uptake rates of 3 elements significantly decreased with body size, but increased with temperature. Simultaneously measured clearance rates of mussels were closely associated with metal uptake rates. The significant association of clearance rates and metal uptake rates of mussels emphasizes the importance of functional role of water pumping activity in the metal uptake process in filter-feeding organisms.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.149-152
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• 2001

Leaf chlorophyll fluorescence capable to estimate $CO_2$ assimilation was compared among three citrus rookstocks: trifoliate orange (Poncitrus trifoliate L.), 'Flying Dragon' (Poncitrus trifoliate L. var. monstrosa) and citromelo (Poncitrus trifoliate L.${\times}$Citrus paradisi), as well as among satsuma mandarin (Citrus unshiu cv. Nichinan No.1) grafted on the 3 rootstocks. Citromelo, the most vigorous rootstock; and 'trifoliate orange'; the most common cultivar and moderate rootstocks gave the same potential and actual quantum yields, whereas 'Flying Dragon' (very dwarf) had lower values due to a higher Fo and Fs for fluorescence obtained from dark-adapted and light-adapted leaves, respectively. These findings show that the absorbed photon energy was dissipated more as fluorescence from the antena chlorophyll in 'Flying Dragon' than trifoliate orange or 'swingle' citrimelo. The satsuma mandarins grafted on these rootstocks did not, however, show the differences observed in the rootstocks by having all the same potential and actual quantum yields. It is suggested that the rootsocks do not potentially or actually electron transport in the Photosystem II (PS II) of satsuma mandarin grafted on the 3 rootstocks.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.447-451
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• 2008

28 kHz 주파수, 조사강도 70 W/L, pH 7로 조정, 조사시간 5 min으로 전처리된 비산재를 사용하여 인공경량골재의 시편을 제조하여 압축강도, 흡수율, 단위용적중량을 분석하였다. 분석 결과 압축강도는 평균 18 MPa 이상으로 측정되어 기준인 18 MPa를 만족하였으며, 흡수율은 국내 기준은 없지만 일본의 기준인 12% 이하보다 매우 높은 흡수율을 나타내었다. 단위용적중량은 기준(1650 kgf/m$^3$ 이하)에는 만족하지만 비교적 낮은 값을 보였으며, 중금속 용출시험결과 측정항목에서 매우 저농도로 나타나 환경상 위해성은 매우 미미할 것이라 판단된다.

• The Journal of the Korean dental association
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• v.10 no.1
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• pp.47-50
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• 1972

저자는 18세부터 24세의 남녀 5명의 치근단병소가 있는 전치에 iodoform paste로 근관과잉충전을 한후 X-선상으로 그 흡수 현상을 관찰 하였던 바 다음과 같은 결론은 얻었다. 1) 비록 동종의 근관충전용 호제(paste)로 근관충전치료를 하였어도 각치아에서의 흡수율에는 큰 차이가 있었다. 2) 요도포름호제의 흡수율은 3,4주에서 보다 1,2주에서 더 빠르게 나타났다. 3) 치근관내에서의 흡수율은 상당히 느렸으며 2주후에 흡수가 나타난 예도 있었다. 4) 치료후 4주간에서는 확산성, 침윤성, 침윤성증상이 X-선상에 나타났으나 3개월후에는 뚜렷한 경계를 가진 병소부를 볼 수 있었으며, 치조골구조의 변화는 병소부의 주위에 신생골의 정밀한 증식으로 연속적인 백선이 형성된 것을 볼 수 있었다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.97-100
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• 2008

In order to recycled wast concrete which is occurred from demolition of the old building, it is effective that the recycled aggregate used as structural concrete aggregate. For used recycled aggregate with structural concrete, the structural capacity must be confirmed. This Study investigated bond capacity which follows in difference of absorption of the aggregate between rebar and concrete. Test results show that there are not a difference of bond strength and slip behavior according to absorption ratio of natural and recycled coarse aggregate.

• Korean Journal of Poultry Science
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• v.41 no.3
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• pp.159-164
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• 2014

This study was conducted to investigate whether water chilling had effect on water retention, freshness or internal temperature of chicken carcasses during chilling or storage in two different chicken processing plants (designated as A and B). A total of 240 carcasses from chicken processing plants (n = 120 per chicken processing plant) was randomly sampled and evaluated the effect of water chilling on carcass characteristics (i.e., water retention, water loss or freshness during chilling or storage). Torrymeter value was used as an indicator of freshness in chicken carcasses. Water chilling did not affect carcass water retention between the processing plants. However, chicken carcasses processing in B plant exhibited significantly higher freshness (p<0.05) compared with those in A plant. This difference in freshness was mainly due to the longer transit time through the water chiller in A versus B plants. Water loss of carcasses during storage was not different between plants. It was found that carcass freshness can be affected by water chilling time as manifested in this study. Further study is warranted to see whether freshness or microbiological status of chicken carcasses may be affected depending on the chilling methods, i.e., air or water chilling.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.2
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• pp.132-139
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• 2015

In this study, the different unit cement content by the ratio of water absorption and water-cement ratio are applied to examine the properties of the concrete used the aggregate recycled by the crushing treatment. According to the experimental results, in the mix of low strength and high water-cement ratio, both of the compressive strength is almost equal in the concrete using the recycled aggregate by the crushing treatment and the concrete using broken stones. It means that the recycled aggregate has the low effect of the amount of bonded mortar. But, in the mix of high strength and low water-cement ratio, the concrete using the recycled aggregate by the crushing treatment has 40% less of the compressive strength than that using broken stones by the effect of the amount of bonded mortar. On the other hand, after 8 weeks, the dry shrinkage of the recycled aggregate with 7% of the ratio of water absorption doubles that of the broken stones with 1% ($-350{\times}10^{-6}$), in other words $-700{\times}10^{-6}$. Thus, the dry shrinkage should be prior to any other conditions in recycling waste concrete for the aggregate for concrete. When the recycled aggregate with 3% of the ratio of water absorption is used, the compressive strength of the rich mix concrete ($450kg/m^3$ of the unit cement content) is equivalent to that of the concrete using broken stones, while in using the recycled aggregate with 7% of the ratio of water absorption, the rich mix concrete has 7% lower compressive strength than the concrete using broken stones. But, the compressive strength of the ordinary mix concrete ($350kg/m^3$ of the unit cement content) is far lower than that using broken stones.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.499-510
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• 2015

Artificial accelerated weathering test evaluated rocks from near the circuit road of Ulleungdo island, approximately 120 km from east of the Korean Peninsula. The tests subjected rock specimens to conditions based on the climate of the island. The specimens (such as basaltic breccia, trachyte, volcanic breccia) were preliminarily classified using a TAS diagram (XRF data) and based on the constituent minerals (XRD data); they were further classified by weathering degree according to their absorption ratios. During the artificial accelerated weathering, the absorption ratio of most of the specimens increased, but the point-load strength did not decrease in most cases, except for the volcanic breccia. The greater initial absorption ratio of trachyte rock specimen in comparison with the other specimens led to a greater increase of its absorption ratio during the artificial accelerated weathering test. The volcanic breccia specimens showed the greatest increase of absorption ratio and the biggest reduction ratio of the point- load strength during the tests. These results could aid prediction of the weathering rate of rocks in Ulleungdo island subjected to weathering processes; trachyte which appears to accelerate with time, and volcanic breccia whose mechanical strength can largely decrease in a relative short period of time. Proper measures therefore appear necessary for the prevention of natural disaster such as rock fall and landslide around the circuit road.