• 한국환경보건학회지
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• 제47권6호
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• pp.540-547
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• 2021

Background: Indoor air pollutants are caused by a number of factors, such as coming in from the outside or being generated by internal activities. Typical indoor air pollutants include nitrogen dioxide and carbon monoxide from household items such as heating appliances and volatile organic compounds from building materials. In addition there is carbon dioxide from human breathing and bacteria from speaking, coughing, and sneezing. Objectives: According to recent research results, most indoor air pollution is known to be greatly affected by internal factors such as burning (biomass for cooking) and various pollutants. These pollutants can have a fatal effect on the human body due to a lack of ventilation facilities. Methods: We fabricated a polydopamine (PDA) layer with Ti substrates as a coating on supported glass fiber fabric to enhance its photo-activity. The PDA layer with TiO₂ was covalently attached to glass fiber fabric using the drop-casting method. The roughness and functional groups of the surface of the Ti substrate/PDA coated glass fiber fabric were verified through infrared imaging microscopy and field emission scanning electron microscopy (FE-SEM). The obtained hybrid Ti substrate/PDA coated glass fiber fabric was investigated for photocatalytic activity by the removal of ammonia and an epidermal Staphylococcus aureus reduction test with lamp (250 nm, 405 nm wavelength) at 24℃. Results: Antibacterial properties were found to reduce epidermal staphylococcus aureus in the Ti substrate/PDA coated glass fiber fabric under 405 nm after three hours. In addition, the Ti substrate/PDA coated glass fiber fabric of VOC reduction rate for ammonia was 50% under 405 nm after 30 min. Conclusions: An electron-hole pair due to photoexcitation is generated in the PDA layer and transferred to the conduction band of TiO₂. This generates a superoxide radical that degrades ammonia and removes epidermal Staphylococcus aureus.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.521-528
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• 2003

This paper presents the results of a cooperative research on remote parallel pseudo-dynamic testing on a base-isolated bridge with multiple piers using Internet between KAIST, Korea and Kyoto Univ., Japan. Experimental facilities located at two institutions were parallelly used to test the nonlinear behavior of the base-isolators. Two data communication schemes for parallel tests were developed and the performance is compared. The results indicate that the elapsed time may vary widely depending on the data communication and testing schemes : i.e. 1-25sec for each time step. But it is fairly comparable with the time required for pseudo-dynamic testing. The testing method can become more powerful, as the data communication and monitoring techniques through Internet improve further.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.206-211
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• 2000

The accelerated testing technique using the equivalent load condition plays an important part in development process. However, in the industrial field, the theoretical background and advantages of this accelerated testing technique have been lack of understanding. Because the environmental durability condition forms the foundation of the accelerated testing technique, it is important to analyze the loading components and damage in service environment. In this work, we present the theoretical background and process for accelerated testing, and introduce our accelerated equivalent load analysis program. We developed the GUI program, and the user can easily obtain the result by selecting the program module.

• 산업경영시스템학회지
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• 제23권60호
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• pp.73-81
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• 2000

The testing processes for VLSI finished devices are considerably complex because they require different types of ATE to be linked together. Due to the interaction effect between two or more linked ATEs, it is difficult to trace down the cause of the unexpected longer ATE setup time and random yields, which frequently occur in the VLSI circuit-testing laboratory. The goal of this paper is to develop and demonstrate the methodology designed to eliminate the possible interaction factors that might affect the random yields and/or unexpected longer setup time as well as increase the productivity. The statistical method such as design of experiment or multivariate analysis cannot be applied to the final testing floor here directly due to the environmental constraints. Expanded product data information (PDI) is constructed by combining product data information and ATE control information. An architecture utilizing expanded PDI is designed, which enables the engineer to conduct statistical approach investigation and reduce the setup time, as well as increase yield.

• Journal of Korean Medical Science
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• 제33권46호
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• pp.304.1-304.7
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• 2018

Background: The Republic of Korea has a very low prevalence of human immunodeficiency virus (HIV) infection, but the number of new HIV diagnoses has steadily risen, strongly indicating a large number of undetected HIV infections. Thus, it is important for Korean public health authorities to adopt and encourage cost-effective HIV detection tools, such as rapid HIV screening tests. In this study, we aimed to evaluate the cost-effectiveness of enzyme-linked immunosorbent assays (ELISA) and rapid tests in a public health center (PHC) setting. Methods: We developed a decision analytic model to assess the per-examinee cost and the cost-effectiveness of identifying HIV patients in a PHC setting using two HIV testing strategies: conventional HIV screening by ELISA versus rapid HIV testing. Analysis was performed in two scenarios: HIV testing in an average-risk population and in a high-risk population. Results: Compared to the ELISA, the rapid test was cost-saving and cost-effective. The per-examinee cost was USD 1.61 with rapid testing versus USD 3.38 with ELISA in an average-risk population, and USD 4.77 with rapid testing versus USD 7.62 with ELISA in a high-risk population. The cost of identifying a previously undiagnosed HIV case was USD 26,974 with rapid testing versus USD 42,237 with ELISA in an average-risk population, and USD 153 with rapid testing versus USD 183 with ELISA in a high-risk population. Conclusion: Rapid testing would be more cost-effective than using conventional ELISA testing for identifying previously undiagnosed HIV-infected cases in Korea, a country with extremely low HIV prevalence.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.761-768
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• 2022

In the hope of realizing carbon neutrality, Korea has established the goal of expanding the supply of hydrogen electric vehicles through a roadmap to revitalize the hydrogen economy. A prerequisite for successful supply expansion is securing the safety of hydrogen electric vehicles. Certain parts, such as the hydrogen transport pipe and tank, in hydrogen electric vehicles are exposed to high-pressure hydrogen gas over long periods of time, so the hydrogen enters the grain boundary of material, resulting in a degradation of the parts referred to as hydrogen embrittlement. In addition, since the safety of parts utilizing hydrogen varies depending on the type of material used and its environmental characteristics, the necessity for the enactment of a hydrogen embrittlement regulation has emerged and is still being discussed as a Global Technical Regulation (GTR). In this paper, we analyze a hydrogen compatibility material evaluation method discussed in GTR and present a direction for the development of Korean-type hydrogen compatibility material evaluation methods.

• Wind and Structures
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• 제25권3호
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• pp.233-259
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• 2017

Investigations on simulated near-surface atmospheric boundary layer (ABL) in an open-jet facility are carried out by conducting experimental tests on small-scale models of low-rise buildings. The objectives of the current study are: (1) to determine the optimal location of test buildings from the exit of the open-jet facility, and (2) to investigate the scale effect on the aerodynamic pressure characteristics. Based on the results, the newly built open-jet facility is well capable of producing mean wind speed and turbulence profiles representing open-terrain conditions. The results show that the proximity of the test model to the open-jet governs the length of the separation bubble as well as the peak roof pressures. However, test models placed at a horizontal distance of 2.5H (H is height of the wind field) from the exit of the open-jet, with a width that is half the width of the wind field and a length of 1H, have consistent mean and peak pressure coefficients when compared with available results from wind tunnel testing. In addition, testing models with as large as 16% blockage ratio is feasible within the open-jet facility. This reveals the importance of open-jet facilities as a robust tool to alleviate the scale restrictions involved in physical investigations of flow pattern around civil engineering structures. The results and findings of this study are useful for putting forward recommendations and guidelines for testing protocols at open-jet facilities, eventually helping the progress of enhanced standard provisions on the design of low-rise buildings for wind.

• 한국지반환경공학회 논문집
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• 제25권7호
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• pp.21-27
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• 2024

동상은 동토지반의 중요한 공학적 특성 중 하나로, 겨울철에 국내에서는 동상으로 인한 다양한 피해가 발생한다. 미국과 일본은 동토지역을 포함하고 있어 동상에 대한 연구가 활발히 이루어졌으며, 표준화된 실험법을 보유하고 있다. 특히, 일본 동상 실험법은 시료 준비와 실험 과정이 비교적 간단하다는 장점이 있다. 그러나 동상 실험 결과의 공학적 해석이 모호하며, 동상 민감성 판정 기준이 제시되지 않아 실제 활용에 문제가 있다. 본 논문에서는 모래-실트 혼합토를 대상으로 일본 동상 실험법에 따라 온도제어형 셀을 활용한 실내실험을 수행하고, 동상속도 산정 과정을 면밀히 분석하였다. 더불어, 일본 동상 실험법으로 산정된 동상속도가 미국에서 제시한 동상 민감성 판정 기준에 적용 가능한지 검토하였다.

• 한국식품영양과학회지
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• 제41권5호
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• pp.674-680
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• 2012

이 연구에서는 비소의 종분리 분석을 위하여 수소화물발생-ICP-AES를 이용하여 무기비소의 As(III)와 As(V)의 신호세기에 대한 citric acid와 HCl 농도의 영향을 조사하였다. 1.5% $NaBH_4$의 농도에서 HCl 농도 1.0 mol/L, citric acid의 농도 2.0%를 사용하였을 때 As(III)만을 선택 분리할 수 있었고, 정도관리 절차에 따라 분석방법을 수행했을 때 방법 검출한계는 0.003 mg/kg, 정량한계는 0.01 mg/kg으로 산출되었으며, 시료의 매질간섭을 확인하기 위한 매질첨가시료 분석과 정도관리시료 분석의 회수율은 80%~110%, 표준편차는 6.2%로 정밀도와 정확도에서도 만족할 만한 수준을 나타내었다. 이에 따라 정도관리시료로 분석한 결과값과 반복성에 의한 측정불확도를 산출하여 인증표준물질의 인증값과 불확도를 비교 통계 처리함으로써 분석방법에 대한 유의성이 없음을 확인하였다. 또한 이 연구에서 제안된 분석방법에 따라 죽염 중에 존재하는 총 무기비소 분석과 비소 종분리 분석을 실시한 결과 총 무기비소의 함량은 0.05 mg/kg에서 0.21 mg/kg 정도로 나타났으며, 분석방법에 따른 여러 불확도 요인들의 표준불확도를 산출하여 죽염 중에 존재하는 As의 불확도를 구한 결과, As의 함량이 0.14 mg/kg에 대하여 확장불확도가 0.03 mg/kg(95% 신뢰수준, $k$=1.96)으로 최종 결과값의 21%를 나타내었다. 위의 결과로 보아 대부분 As(V)의 형태로 존재하며 일부 시료에 대해 As(III)의 함량이 각각 0.02 mg/kg으로 총 무기비소함량의 14.3%와 9.5%를 차지하는 것으로 나타났다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제5권2호
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• pp.209-219
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• 2005

The required standards for environmental tests for communication and electronic equipment used currently are not standards into which the Korean climate and use environment are taken into consideration. But the most used environmental testing standards of the U.S. army(MIL-STD-810) has been used without taking into consideration the Korean domestic situation and conditions by simply translating the US standards. Adherence to these standards may increase in the manufacturing costs according to excessively strict standards. Therefore, this paper will propose a new environmental test standards for temperature.