• 해양환경안전학회지
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• 제25권5호
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• pp.609-616
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• 2019

선박에 파울링이 발생되면 운항 중 선박의 저항이 증가하게 되고 이로 인해 연료 소모량도 높아지게 된다. 또한 파울링의 제거에 많은 시간이 필요하게 되어 전체적으로 선박의 유지보수 비용이 증대되는 문제점이 있다. 이러한 문제점을 해결하고 환경오염을 방지하기 위해 주석과 같은 독성 물질을 포함하지 않는 자기연마형 방오도료를 개발하고 있다. 이와 같은 종래기술은 해수와의 마찰이나 진동이 많이 발생하는 운항 중에는 연마기능이 촉진되어 방오성능이 증대되나, 정박 중과 같이 실제로 파울링이 심화되는 경우에는 해수의 흐름이 없어 연마기능이 저하되어 방오성능이 떨어지는 문제점이 있다. 이러한 문제점을 해결하기 위해 선체의 진동 및 해수의 흐름이 없어서 연마 기능이 저하되는 정박 중에도 진동을 부여하여 연마 기능의 저하를 방지하는 제품을 개발하였다. 개발된 초음파 방오장비의 성능의 신뢰성을 위해 파형발생기의 반복성을 확인하였고 장치의 파울링 제거효율의 정성적인 경향은 시편을 통해 파악하였다. 실험 결과 주파수와 진폭의 반복성의 변동계수 값은 평균 0.2 %, 4.0 %를 나타냈고 시편의 파울링 발생량은 No.5 시편에서 73.3 g으로 가장 많았고 파울링 제거효율은 장치를 설치하지 않은 시편과 비교하여 평균 93.2 % 값을 확인할 수 있었다.

• 전자공학회논문지
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• 제50권12호
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• pp.184-190
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• 2013

파라메트릭 스테레오 오디오 부호화는 공간 오디오 기법 중 스테레오에 특화된 부호화 기법이다. 본 논문에서는 기존의 파라메트릭 스테레오 기법에서 채널간 위상차 합성시 발생하는 문제점을 분석하였다. 기존의 업믹스 행렬에서는 채널간 위상차를 다운믹스 신호뿐만 아니라 잔향신호에도 합성하고 이로 인하여 반위상 관계를 위반한다. 채널간 상관도가 낮을 때, 잔향 성분에 대한 채널간 위상차 합성으로 인하여 발생하는 음질열화를 분석하였다. 이러한 문제점들을 해결하기 위하여 신호 모델을 만족할 수 있도록 주요 성분에만 채널간 위상차를 합성하는 업믹스 행렬을 제안하였다. 주관적 음질 평가를 통하여 제안된 업믹스 행렬의 성능을 검증하였다.

• 열처리공학회지
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• 제10권2호
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• pp.101-108
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• 1997

In high carbon steels, the cementite phase is more unstable thermally than graphite, and it can lead to a marked deterioration in the formability. Many studies have been carried out to evaluate the effect of the fundamental elements on the graphitization of cementite in high carbon steels. In this present work, the effect of Mn, Cr addition on graphitization in Fe-0.65%C-1.0%Si steel has been investigated by means of hardness testing, optical microscopy and EPMA. The nucleation of graphite may mostly depend on the dissolution rate of cementite into ferrite and the number of the nucleation sites of graphite. The graphitization was promoted by the addition of 0.1%Mn in high carbon steel, but retarded by more addition than 0.5% of Mn. By the more addition of Cr than 0.1%, the graphitization of high carbon steel was strongly retarded. Because Mn was moderate anti-graphitizer, but Cr was stroug anti-graphitizer.

• 헤리티지:역사와 과학
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• 제48권4호
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• pp.62-73
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• 2015

세계문화유산인 조선왕릉 중 태조 건원릉은 조선 제1대 임금인 태조 이성계의 무덤으로 다양한 종류의 석물이 배치되어 있다. 모든 석물들은 중립질 흑운모화강암으로 구성되어 있으나, 위치에 따라 훼손형태 및 손상도의 차이를 나타내고 있다. 석물의 훼손도를 평가한 결과, 주요 훼손 양상은 물리적 훼손과 생물 오염으로 확인되었다. 이 중에서 박리박락, 탈락, 입상 분해와 같은 물리적 훼손 유형은 봉분 석재와 주변 석물이 유사한 발생 빈도를 나타내지만 토사, 선태류, 초본식물 및 보수 물질의 비율은 봉분 석재에서 상대적으로 높은 것으로 나타났다. 이는 봉분에서 지속적으로 유입되는 토양 및 수분, 지면과의 거리 및 일사량 저하 등으로 수분의 지속시간이 증가하여 물리적 및 생물학적 훼손이 주변 석물에 비해 빠르게 진행된 것으로 판단된다. 따라서 건원릉 석물의 훼손을 저감하기 위해서는 수분 제어와 함께 봉분 석재를 중심으로 생물의 제거가 요구되며 물리적 훼손이 심한 부재는 강화처리 및 접착 등 물리적인 보강이 필요하다.

• Journal of Korean Neurosurgical Society
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• 제64권6호
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• pp.873-881
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• 2021

Objective : Peripheral nerve injuries occur mostly as a result of mechanical trauma. Due to the microvascular deterioration in peripheral nerve damage, it becomes challenging to remove free oxygen radicals. Gallic acid is a powerful antioxidant with anti-inflammatory effects and a free radical scavenger. The purpose of the study is to show that gallic acid contributes to the restorative effect in mechanical nerve damage, considering its antioxidant and anti-inflammatory effects. Methods : Thirty male Sprague Dawley albino mature rats were included in the study. Ten of them constituted the control group, 10 out of 20 rats for which sciatic nerve damage was caused, constituted the saline group, and 10 formed the gallic acid group. Post-treatment motor functions, histological, immunohistochemical, and biochemical parameters of the rats were evaluated. Results : Compared to the surgery+saline group, lower compound muscle action potential (CMAP) latency, higher CMAP amplitude, and higher inclined plane test values were found in the surgery+gallic acid group. Similarly, a higher nerve growth factor (NGF) percentage, a higher number of axons, and a lower percentage of fibrosis scores were observed in the surgery+gallic acid group. Finally, lower tissue malondialdehyde (MDA) and higher heat shock protein-70 (HSP-70) values were determined in the surgery+gallic acid group. Conclusion : Gallic acid positively affects peripheral nerve injury healing due to its anti-inflammatory and antioxidant effects. It has been thought that gallic acid can be used as a supportive treatment in peripheral nerve damage.

• KEPCO Journal on Electric Power and Energy
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• 제2권4호
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• pp.615-618
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• 2016

Electrochemical noise(EN) has been used to analyze the deterioration of coating films of offshore wind substructures. In this study, prototype sensors using EN have been developed to detect the corrosion rate. To verify the reliability of sensors, experiments were conducted both in the laboratory and offshore using probe and standard samples. New analysis and data processing techniques show that the sensor can provide useful information about the corrosion rate.

• 셀메드
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• 제3권4호
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• pp.27.1-27.13
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• 2013

Epilepsy has now become the most serious brain disorder. A number of synthetic antiepileptic drugs are available in practice, however their effectiveness does not grip true with the entire population suffering from epilepsy. Traditional systems of medicine are popular in developing countries and most of the population relies on traditional medicines for their primary health care need. Medicinal plants to be an important source of traditional medicines. Various plants are used for the treatment of epilepsy in traditional system of medicines and various plants are yet to be scientifically investigated. Phytoconstituents have been the basis of treatment of human diseases including epilepsy. Herbal products are extensively used for the treatment of many diseases worldwide and where allopathic fails or has severe side effects. Psycho neural drugs are also have very serious side effects like physical dependence, tolerance, deterioration of cognitive function and effect on respiratory, digestive and immune system. So the treatments through herbal medicines are widely used across the world due to their wide applicability and therapeutic efficacy with least side effects, which in turn has accelerated the research regarding natural therapy. In this review we have summarized some herbal antiepileptics.

• 한국정밀공학회지
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• 제25권3호
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• pp.109-114
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• 2008

The solenoid valve of ABS hydraulic modulator is a two directional on-off valve and is controlled by around 100Hz on-off control. When the on-off valve is switched from open state to closed state, there are braking force deterioration, noise and vibration due to surge pressure in the wheel cylinder. In this study, identifies surge pressure in the braking process of ABS, and investigates the way to reduce the phenomenon. To reduce the surge pressure, PWM(Pulse Width Modulation) control with high frequency of 20kHz was attempted. In conclusion, by using the results of this study for the pressure surge prediction, we could expect enhancement of braking performance in ABS.

• 혜화의학회지
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• 제21권1호
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• pp.33-52
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• 2012

To evaluate the efficacy of Keonkangbujatang (KKBT) in osteoarthritis treatments, C57BL/10 mice were treated with papain to induce osteoarthritis, and anti-arthritic effects were measured. To ensure safety of the KKBT sample, ALT, AST, BUN, and creatinine levels were measured, and they were all within the normal range. Based on the fact that suppression of inflammatory cytokines leads to the improvement of arthritis, IL-1b, IL-6, TNF-a, and MCP-1 production levels were measured. The cytokines were significantly decreased in serum. Also, mRNA levels of IL-1b, IL-6, and iNOS-II were significantly decreased in joint tissues. PGE2, a usual inflammation vector, and LTB4, TXB2, that are involved in the onset and deterioration of inflammation, were all significantly decreased. The levels of white blood cells, neutrophiles, and mononucleophiles also decreased, although the numbers were not significantly large. I*mmune-modulation of KKBT in the pathological mechanism of cartilage deterioration by inflammatory cells and their vectors was proved. This study should provide basis for the development of effective therapeutics as well as use in clinical practice.

• 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