• Structural Engineering and Mechanics
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• 제54권6호
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• pp.1111-1133
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• 2015

Rebar corrosion in concrete is one of the main causes of reduction of service life of reinforced concrete buildings. This paper presents the influence of rebar corrosion on the structural behavior of reinforced concrete (RC) buildings subjected to strong earthquake ground motion. Different levels of rebar corrosion scenarios were applied on a typical four story RC frame. The deteriorated conditions as a result of these scenarios include loss in cross-sectional area and loss of mechanical properties of the reinforcement bars, loss in bond strength, and loss in concrete strength and its modulus of elasticity. Dynamic analyses of the frame with different corrosion scenarios are performed with selected strong earthquake ground motion records. The influences of degradation in both concrete and reinforcement on structural behavior are investigated by comparing the various parameters of the frame under different corrosion scenarios with respect to each other. The results show that the progressive deterioration of the frame due to rebar corrosion causes serious structural behavior changes such as change in failure mode. The intensity, propagation time, and extensity of rebar corrosion have very important effects on the level of degradation of steel and concrete, as well as on the earthquake behavior of the structure.

• 전기학회논문지
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• 제57권4호
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• pp.551-559
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• 2008

Increase in power consumption can cause a serious stability problem of an electric power system without construction of new power plants or transmission lines. Also, it can generate large power loss of the system. In costly and environmentally effective manner to avoid constructing the new infrastructures such as power plants and transmission lines, etc, the distributed generation(DG) has paid great attentions so far as a solution for the above problem. Selection of optimal location and size of the DG is the necessary process to maintain the stability and reliability of existing system effectively. However, the systematic and cardinal rule for this issue is still open question. In this paper, the method to determine optimal location of the DG is proposed by considering power loss when the DG is connected to an electric power grid. Also, optimal size of not only the corresponding single DG but also the multi-DGs is determined with the proposed systematic approach. The IEEE benchmark 30-bus test system is analyzed to evaluate the feasibility and effectiveness of the proposed method.

• 문화기술의 융합
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• 제9권4호
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• pp.543-548
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• 2023

한국은 괄목할 만한 경제성장을 이루며 선진국 행렬에 들어섰지만 높은 산업재해 발생률로 인해 근로자의 안전이 위협받고 많은 재산 손실을 초래하는 문제점이 여전히 존재하고 있다. 산업재해 발생률을 낮추기 위해 2020년 4월 산업안전보건법을 전면 개정하며 안전관리를 강화하였지만, 사망재해자 수는 오히려 증가하였다. 이에 정부와 국회는 2022년 1월 중대재해 처벌 등에 관한 법률을 시행하였지만, 그 효과를 확인하지 못하고 있다. 이에 본 연구는 중대재해처벌법 시행 후 건설현장 근로자와 관리자의 안전의식에 어떤 영향을 주었는지 관계자 설문을 통해 분석하였고 안전관리를 개선할 수 있는 대책을 제시하였다.

• 한국정밀공학회지
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• 제17권9호
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• pp.81-86
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• 2000

This paper was carried out to investigate the characteristics of interlaminar fracture toughness of foam core sandwich structures under opening loading mode by using the double cantilever beam (DCB) specimens in Carbon/Epoxy and foam core composites. instead of using symmetric geometry of DCB specimen non-symmetric DCB specimen was used to calculate the interlaminar fracture toughness. Three approaches for calculating the energy release rate({{{{ {G }_{IC } }}}}) were compared. Fracture toughness of foam core sandwich structures by autoclave vacuum bagging and hotpress were compared and analyzed. Experiment nonlinear beam bending FEM method were performed. Suggested bonding surface compensation and equivalent area inertia moment was used to calculate the energy release rate in nonlinear analytical results. The conclusions among experimental nonlinear analytical and FEM results was observed. The vacuum bagging method was shown to be able to substitute method in stead of autoclave without serious loss of Mode I energy release rate({{{{ {G }_{IC }}}}}) to be able to substitute method in stead of autoclave without serious loss of Mode I energy release rate({{{{ {G }_{IC }}}}}).

• 한국임상약학회지
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• 제28권3호
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• pp.243-249
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• 2018

Background: The new type of diabetes treatment, SGLT2 inhibitors, has been approved for monotherapy and combination therapy, but medical insurance is only allowed in combination therapy with metformin, which is the first choice for type 2 diabetes treatment. Methods: The SGLT2 inhibitors prescribed in Korea are dapagliflozin, empagliflozin and ipragliflozin. A review was conducted using Pubmed to evaluate efficacy and safety for these medications with metformin combination therapy. 10 studies were selected by searching for keywords and related references and were reviewed in full. The mechanism of action, pharmacokinetics, and the economics of treatment with SGLT2 inhibitors were examined. Results: SGLT2 inhibitors had moderate glycemic control when added to the treatment of patients with type 2 diabetes who were not being regulated by metformin monotherapy. They also showed positive effects such as weight loss, as well as the lowering of blood pressure. Hypotension and serious side effects were relatively low. However, the risk of genital infection was increased. Conclusion: The SGLT2 inhibitors are a new class of drugs that promote glucose excretion in the urine. They are a good choice for combination therapy with metformin for the treatment of type 2 diabetes, with weight loss and very low risk of serious side effects.

• 한국초전도ㆍ저온공학회논문지
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• 제6권4호
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• pp.32-36
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• 2004

AC loss is one of the important parameters in HTS (High Temperature Superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in electrical power system. But, AC loss is one of the most serious problems of the HTS transformer, especially with pancake windings, because high alternating magnetic field is applied perpendicularly to the surface of BSCCO wire in HTS windings of that, comparing with the other HTS AC power devices. For the reason above the calculation of AC loss generated in the HTS windings should be carried out in advance when designing the HTS transformer. In the paper we performed study for optimization of winding design to minimize the magnetization loss of HTS winding such as the spaces between pancake windings and operating temperature of HTS wire. The calculation of the AC loss was accomplished by 2-demensional Finite Element Method.

• Journal of the Korean Wood Science and Technology
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• 제21권2호
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• pp.9-14
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• 1993

Weathering of wood in a region of acid rain was performed by the test which thin veneers of Sitka spruce were exposed to outdoor weathering for a total of 18 weeks, with a daily soaking for 30 minutes in acidified water in the pH range 2~5.6. The weathering measured by weight loss and loss in maximum failure load in tension was accelerated by the increase in the acidity of acidified water and in the period of outdoor exposure. It was also shown that the weathering was accelerated even with low acidic conditions in the case of long exposure period, although the weathering was rapidly accelerated with high acidic conditions. When compared the degree of weight loss with that of loss in failure load by weathering, the latter was much greater. From the results of this research, it could be concluded that at pH 4.0 or below of precipitation, the acceleration of weathering of exterior wood would become serious problems, which would be caused deterioration in performance of exterior wood.

• 한국화재소방학회논문지
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• 제15권1호
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• pp.47-54
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• 2001

90년대 후반기부터 연이어 발생한 씨랜드 화재사고와 인천 인현동 라이브클럽 화재등의 동일한 유형을 가진 화재사건을 계기로 국내 다중이용업소의 실내장식재 및 장식물품에 사용하는 재료가 화재시 인명참사에 미치는 영향이 크다는 점이 발견되었다. 따라서 국내다중이용업소를 중심으로 실내장식재 및 장식물품의 사용과 관련한 화재안전규정 및 기준을 조사한 후에 유럽·미국 등의 선진국의 관련 규정을 조사 비교하여 그 문제점을 세부적으로 발췌하여 규제방향 및 규제기준의 상이점을 분석하여 대형인명참사를 초래하는 근본적인 원인을 찾아내었다. 고찰된 원인을 근간으로 실내장식재 및 장식물품에 사용하는 재료가 선진국 수준의 방재성능을 가질수 있도록 규제방향을 제시하고 제시된 규제방향을 뒷받침할 수 있는 효과적이고 검증된 시험방법을 연구제시하였다. 최종적으로 향후 발생가능한 대형인명참사를 효과적으로 방지하기 위해 다중이용업소를 중심으로 방화 및 방염제도의 효과적인 수립디 되도록 실내장식재 및 장식물품에 대한 세부규제안을 기술하여 방화 및 방염제도의 세부규안을 제시하였다.

• 대한인간공학회지
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• 제18권2호
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• pp.47-55
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• 1999

Recently, noise from personal cassette players (PCP) poses growing concerns together with occupational noise-induced hearing loss. Eighteen male and female volunteer subjects participated to determine preferred noise levels for PCP usage before, during, and after 2-hour subway riding according to sources (types) of PCP listening (language/news, soft music, and hard music). Audiometric tests were conducted before and after the 2-hour exposure of PCP noise under subway riding. Statistical analyses showed some significant hearing losses with the greatest loss of more than 6 dB at 4000 Hz for both ears, indicating that serious noise-induced hearing loss would potentially occurred due to prolonged use of PCPs. Practical safety countermeasures against PCP noise are further discussed.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2004년도 Annual Meeting and International Symposium
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• pp.103-109
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• 2004

The obese population has been increasing over the world wide and obesity became a socioeconomic problems. It is become more serious by the accumulation of the knowledge that the obesity is related directly or indirectly with several diseases like, diabetes, hypertension, etc. With these reasons, many functional food or agents for the purpose of weight loss have been developed. However, most of these remedies are unproven and some have produced even dangerous side effects due to the ephedrine alkaloids contained in Ma-Hang. Because of these reasons, they banned using of these agents in US and regards the antiobesity functional agents as drugs in Europe. Several functional agents are known for weight loss activities like, HCA, L-canitine, CLA, chitosan, calcium supplements and capsaicin containing red pepper, kimchi and kochujang. We describe here about the function, efficacy and mechanism of these antiobesity functional agents. Furthermore, the trial of the mixture of weight loss related herbal ingredients for safe multifunctional antiobesity functional agents are discussed here, as well.