• 한국입자에어로졸학회지
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• 제7권3호
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• pp.87-97
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• 2011

In this study, we organized the test results obtained from the performance tests for the CA certificated air cleaners which had been commercially available in Korea since 2003, and analyzed the correlation among the test parameters such as flow rate, particle collection efficiency, clean air delivery rate (CADR), ozone emission, odor removal efficiency and noise level etc. The noise level of 267 air cleaners were increased as concentrated at the 45, 50, 55 dB, which are the required noise level for CA certification according to flow rate, and ozone emissions from the CA air cleaners were significantly lower than the requirement limit, 50 ppb for 24 hour operation. The average particle collection efficiency and odor removal efficiency were 89.3 and 80.8%, approximately 20% higher than the requirement of CA certification, regardless of flow rates. The particle removal performance of an air cleaner was clearly discriminated by its CADR, and the CADR was obtained with a simple calculation: 0.79 x flow rate. The low differentiation of gas removal performance of air cleaners by the current CA gas test method was improved by 3.2, 751.3, 13.4 times for ammonia, acetic acid, respectively, by adopting the CADR concept and the real time measurement method, FTIR, for gas removal performance test.

• Toxicological Research
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• 제21권2호
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• pp.99-105
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• 2005

Photo-mutagenic compounds have been known to alter skin cancer rates by acting as initiators or by affecting subsequent steps in carcinogenesis. The objectives of this study are to investigate the utility of photo-chromosomal aberration (photo-CA) assay for detecting photo-clastogens, and to evaluate its ability to predict rodent photocarcinogenicity. Photo-CA assay was performed with five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-Methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an alpha-adrenergic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and Retinoic acid (a retinoid compound closely related to vitamin A). For the best discrimination between the test substance-mediated genotoxicity and the undesirable genotoxicity caused by direct DNA absorption, a UV dose-response of the cells in the absence of the test substances was firstly analyzed. All 5 test substances showed a positive outcome in photo-CA assay, indicating that the photo-CA test is very sensitive to the photo-genotoxic effect of UV irradiation. With this limited data-set, an investigation into the predictive value of this photo-CA test for determining the photo-carcinogenicity showed that photo-CA assay has the high ability of a test to predict carcinogenicity. Therefore, the photo-CA test using mammalian cells seems to be a sensitive method to evaluate the photo-carcinogenic potential of new compounds.

• 한국주조공학회지
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• 제32권1호
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• pp.44-49
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• 2012

In this study, three magnesium alloys were investigated; those are 1.5wt.% CaO added AM80, 1.0wt.% CaO added AM60, and conventional MRI153 alloys. Test specimens of three alloys were prepared by re-melting and casting into steel mold with ingots and machining. The mechanical properties and the creep behavior at 150 degrees Celsius of these specimens were determined and their microstructures were characterized using OM and SEM. For the application to die-casting, fluidity test were carried out with spiral mold. Compared with 1.0wt.% CaO added AM60 alloy, 1.5wt.% CaO added AM80 alloy exhibited good creep properties in all test conditions. Moreover, CaO added alloys showed better creep properties than MRI153 alloy at lower load condition. It is proposed that 1.5wt.% CaO added AM80 alloy is useful to apply to power-train parts such as transmission case in vehicles.

• Journal of Nutrition and Health
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• 제43권1호
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• pp.12-25
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• 2010

본 연구는 $CaCO_3$를 표준으로 장내 칼슘 흡수를 촉진하는 peptide-Ca, anchovy-Ca, methionine hydroxyl analogue calcium의 생체이용성과 소화율을 평가하였다. 표 준군은 $CaCO_3$를 AIN-93G (1993)를 기준으로 칼슘 요구량의 0%, 30%, 60%로 첨가하여 모든 분석 항목에 대한 비교기준으로 삼았다. 실험군은 요구량의 40% 수준으로 각기 다른 칼슘 공급원으로 실험하였다. 실험결과는 대부분 칼슘 함량이 높은 Ca-60%군이 가장 높은 수치를 보여 주어 칼슘의 섭취량과 비례하여 양의 상관 관계를 보여 주었다. 생체이용성 평가에서는 MHA-Ca 군이 체중 증가량, BMD, BS, BBS 항목에서 높은 이용성을 보여 주었다. peptide-Ca은 회귀계수가 높은 회분함량 ($R^2\;=\;0.98$)과 BMC ($R^2\;=\;0.935$)를 이용한 평가 에서 표준군에 비해 11%, 7% 높은 이용성을 보여주었다. Anchovy-Ca군 역시 여러 생체이용성 평가항목에서 높은 이용성을 나타냈다. 이는 동일한 양의 칼슘을 섭취했을 때 실험군이 표준으로 사용된 $CaCO_3$ 보다 높은 칼슘 이용성을 가지고 있음을 의미한다. 하지만 본 연구로는 유기태 칼슘이 어떤생리 활성 작용을 통해 이러한 결과를 나타냈는지는 알 수 없었으며, 이 부분을 분명하게 규명하는 추가적인 연구가 필요한 것으로 판단된다. 소화율 측정항목에서는 Ca-0%군을 제외하고는 90% 이상 높은 칼슘 소화율을 나타냈다. 소화율과 보유율에서 peptide-Ca군이 유의한 차이는 없었지만 다른 실험군에 비해 미세하게 높았다. 이러한 차이의 축적으로 인해 생체이용성 평가시 실험군간 차이를 보여 주었다. 결국 공급한 칼슘에 대한 소화 및 흡수의 차이에 의해 뼈 건강관련 지표가 좋아지고 이로 인해 실험군의 생체 이용성이 높게 평가 되었다. Peptide-Ca와 순수한 식품 칼슘 급원인 멸치 뼈는 높은 칼슘 이용성을 나타내어, 체내칼슘 영양개선에 상당한 효과가 있슴이 증명되었다.

• 한국주조공학회지
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• 제31권2호
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• pp.60-65
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• 2011

Molten magnesium alloys and magnesium products are easily oxidized and burned when they are exposed to high temperature for manufacturing process and by accident. In order to solve these problems, CaO addition in magnesium alloys has been developed. The ignition resistance of CaO added Mg-3Al, Mg-6Al, and Mg-9Al Eco-Mg alloys were investigated in comparison with those of magnesium alloys without CaO. The ignition resistance was examined by three methods : DTA, furnace chip ignition test, and torch ignition test. DTA was carried out for obtaining quantitative ignition temperature data with respect to specimen geometry and test environment; the furnace ignition test for burr and chip ignition temperature data; and the torch test for ignition temperature data for manufactured products. The ignition resistance of magnesium alloys under all conditions greatly increased by CaO addition.

• 한국세라믹학회지
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• 제30권6호
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• pp.433-440
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• 1993

The bioactivity of glasses in the CaO-SiO2 system and CaO-P2O5-SiO2 system with less than 10mol% of P2O5 was investigated by in vitro test in simulated body flood(SBF). The formation of Ca.P film and hydroxyapatite on the surface of glasses after in vitro test was analysed by X-ray photoelectron spectoscopy (XPS), fourier transform infrared reflection spectroscopy (FT-IRRS), energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) observation. In the early stage of Ca.P film formation after in vitro test for CaO-SiO2 and CaO-P2O5-SiO2 glasses, the rate of Ca.P film formation on the surface of the glasses was dependent of structural parameter (Y) evaluated from the glass composition. First, in the case of the glasses having Y value below 2, Ca.P film and SiO2-rich layer were formed simultaneously, and there were no differences of the rate of Ca.P film formation in terms of the Y values. Second, in the case of the glasses having Y value above 2, the SiO2-rich layer was formed, and then Ca.P.Si mixed layer was formed in the silica gel structure of the SiO2-rich layer, and finally the Ca.P film on the surface of SiO2-rich layer. The rate of Ca.P film formation delayed as the Y values increased. The rate of hydroxyapatite formation of glasses (the rate of transformation from Ca.P film to hydroxyapatite) seems to be propotional to the rate of Ca.P film formation and Y value. The rate of hydroxyapatite formation of glasses belonging to the second group was delayed as structural parameter increased, and the hydroxyapatite crystal showed spherical growth in the early reaction stage, and then showed silkworm-like linear growth as the reaction time increased.

• 핵의학기술
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• 제13권3호
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• pp.185-188
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• 2009

목적 : 건진센터 종양 검사가 정상범위 내에서 재검기준이 명확히 설정되어 있지 않아 검사자마다 각자의 재검기준에 따라 재검을 시행함에 따라 재검상의 편차가 크고 일괄적이지 못했다. 이를 개선하기 위해 정상치이하값에서의 재검기준을 마련하고 정상치이하인 값에서 trend 결과를 관리할 수 있는 본원 OCS QC (order communication system quality control)프로그램을 이용하여 건진 센터 종양 검사의 결과보고오류에 개선을 하고자 한다. 대상 및 방법 : 2009년 2월부터 3월까지 본원 건진 센터에서 종양 검사(AFP, CEA, CA19-9, CA125, PSA)를 실시한 환자들을 대상으로 하였다. 우선 각 검사의 정상범위에서 Inter assay CV%를 구하여 screening 기준 값을 설정하였다. OCS QC program에 진료과, 대상 검사종목, screening 기준 값을 입력하여 기준 값에 벗어난 결과는 색깔에 반전을 주었다. 1차로 5가지종양 검사를 전 결과대비 ${\pm}$ 30% 기준을 벗어난 screening 건수를 구하였고 2차로 각각의 종양 검사에 대해 전 결과 대비 AFP는 ${\pm}$ 60%, CEA와 CA19-9는 ${\pm}$50%, CA125와 PSA는 ${\pm}$40%로 기준 값을 상향조정하여 screening 건수를 구하였으며 정상치 이하에서의 재검기준도 설정하여 비교하였다. 결과 : 1차 screening 건수 백분율은 30~40%의 결과를 얻었고, 2차 screening 건수 백분율은 AFP 26.1%, CEA 18.9%, CA19-9 17.3%, CA-125 18.7%, PSA 21.0%로 평균 20%의 screening 백분율을 얻었다. 정상치 이하에서의 재검기준은 AFP 5.0이하$\leftrightarrow$10.0이상, CEA 1.0이하$\leftrightarrow$3.0이상, 2.0이하$\leftrightarrow$4.0이상, CA19-9와 CA-125 10.0이하$\leftrightarrow$30.0이상, PSA 1.0이하$\leftrightarrow$2.0이상으로 정하였으며 평균 20.4%의 screening 백분율에 재검기준을 적용시켜 실제 재검사 건수를 얻었다. 2달 동안 재검사 건수는 AFP 0건, CEA 15건, CA19-9 3건, CA-125 2건, PSA 5건이었다. 결론 : OCS QC 프로그램을 이용하여 시스템적인 재검기준을 마련함으로 검사자간 재검 실시 편차의 감소가 있었고 정상치 이하 값에서 결과보고오류에 대해 개선이 있을 것으로 사료된다.

• 핵의학기술
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• 제27권1호
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• pp.55-61
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• 2023

Purpose In this study, the monthly population distribution was calculated for statistical verification of 10 tests (CA19-9, CA15-3, testosterone, PTH, calcitonin, AFP, CEA, CA72-4, PSA, estradiol) with changed reagents, and the trend of change By comparing and analyzing the results, we want to verify the accuracy of the results and improve the reliability of the test. Materials and Methods From June 2021 to February 2023, for the 10 items in which the reagent was changed, the monthly percentage and standard deviation index before and after the reagent change were compared, respectively. At this time, the reference value was arbitrarily set for the comparison group in consideration of the reference value of the test item, and the groups were subdivided and compared, and the standard deviation index allowed range was -2.0 or more and 2.0 or less. Results For CA19-9, CA15-3, AFP, CEA, and calcitonin 5 test items, the change in monthly ratio in all test sections before and after the reagent change was kept constant. On the other hand, for CA72-4, PSA, testosterone, PTH, and estradiol items, the standard deviation index exceeded the acceptable standard after changing the reagent. CA72-4 test items showed an increasing trend in standard deviation index in the test section exceeding the reference value. In the case of the PSA test item, the maintenance ratio of 0.04 ng/mL was significantly decreased after changing the reagent. The testosterone test item had a standard deviation index of -2.5 in the test section exceeding 10.1 ng/mL after changing the reagent, and the standard deviation index of the PTH test item was out of the acceptable range in all test sections. It was confirmed that the estradiol test item showed an overall increase in the result value. Conclusion Through this study, the continuity and accuracy of the test results could be verified. It is considered that the stability of the test can be secured by analyzing the factors affecting the test result and solving the cause for the test item whose standard deviation index is out of the acceptable standard.

• Korean Chemical Engineering Research
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• 제43권6호
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• pp.722-727
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• 2005

Dow99Ca350, MFG-220, Finex CS-10GC는 이온 교환 수지로써, 당 분리에 주로 사용되며, 모두 poly styrene DVB를 기본 골격으로 술폰산염, 혹은 술폰산을 작용기로 하고 있다. 이 분리 수지들은 이미 제당 산업의 연속 분리 공정에서 사용되고 있으며, 이에 대해 본 실험은 온도의 영향으로 인한 Dow99Ca350, MFG-220과 Finex CS-10GC의 분리수지에서 당의 체류 혹은 흡착 특성 변화를 알아보기 위하여 수행되었다. 당 분리의 시료로써 사용된 물질은 과당과 포도당으로써 위의 분리 수지와 함께 제당 산업에서 널리 사용된다. Dow99Ca350의 팽윤 시험, 공극률 시험, 펄스 시험, 전단 분석을 통해 온도에 대한 영향을 확인하였다. MFG-220, Finex CS-10GC의 경우, 펄스 시험을 통해 온도 변화에 의한 크로마토그램의 변화를 알아보았다. 실험의 결과 Dow99Ca350, MFG-220과 Finex CS-10GC는 과당과 포도당 각각 최대 1.76, 3.37％의 체류 시간 변화를 보임으로써 온도에 안정적인 경향성을 보였다.

• 한국산업융합학회 논문집
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• 제25권2_2호
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• pp.289-297
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• 2022

Deterioration in durability of structures due to the steel corrosion is difficult to determine whether or not corrosion is initiated and how much propagated, and moreover, repair and maintenance are not easy to deal with. Therefore, preventive treatments can be the best option to avoid the deterioration. Various methods for preventing corrosion of steel, such as electrochemical treatments, anti-corrosion agents and steel surface coatings, are being developed, but economic and environmental aspects make it difficult to apply them to in-situ field. Thus, the purpose of this study was to improve corrosion resistance by using CA-based clinker that are relatively simple and expected to be economically profitable Existing CA-based clinkers had problems such as flash setting and low strength development during the initial hydration process, but in order to solve this problem, CA clinker with low initial reactivity were used as binder in this study. The cement paste used in the experiments was replaced with CA₂ clinker for 0%, 10%, 20%, and 30% in OPC. And the mixture used in the chloride binding test for the extraction of water-soluble chloride was intermixed with Cl- 0.5%, 1%, 2%, and 3% by weight of binder content. To evaluate characteristic of hydration heat evolution, calorimetry analysis was performed and simultaneously chloride binding capacity and acid neutralization capacity were carried out. The identification of hydration products with curing ages was verified by X-ray diffraction analysis. The free chloride extraction test showed that the chlorine ion holding ability improved in order OC 10 > OC 30 > OC 20 > OC 0 and the pH drop resistance test showed that the resistance capability in pH 12 was OC 0 > OA 10 > OA 20 > OA 30. The XRD analyses showed that AFm phase, which can affect the ability to hold chlorine ions, tended to increase when CA₂ was mixed, and that in pH12 the content of calcium hydroxide (Ca(OH)₂), which indicates pH-low resistance, decreased as CA₂ was mixed