• Journal of the Korean institute of surface engineering
• /
• v.36 no.2
• /
• pp.184-193
• /
• 2003

Cyclic sweep voltametry was performed to investigate the electrochemical behavior of heavy metal ions and the organic additives in surface finishing process. And electrolysis using parallel plate electrode electrolyzer was carried out to simulate the treatment of real waste water. Results showed that more than 99 percent of Cu was recovered and selective recovery of Cu in mixed waste water was possible, but the possibility of economical recovery of Ni and Cr were very low due to the evolution of hydrogen gas. Electrochemical oxidation of cyanide and organic additives on anode showed very excellent removal rate. The complete removal of several hundred ppm of cynide was possible within several tens minutes and organics within 2 or 3 hours. Even in case of concentrate waste water, the complete removal of COD by using NaCl and air stirring seemed to be possible.

• Proceedings of the KIPE Conference
• /
• 2001.07a
• /
• pp.623-626
• /
• 2001

The neon transformer consists of magnetic circuit and leakage transformer. Since the silicon steel plate is used build a core, the system is big and heavy. Thus it is difficult to install Neon Sign it is even very dangerous if the system experiences a damage when it is installed inside. To overcome these problems, power electronic circuits are applied. The Inverter type Neon transformer using MOSFET is designed and implemented. The experimental results are described.

• Clinics in Shoulder and Elbow
• /
• v.22 no.2
• /
• pp.106-109
• /
• 2019

Acromial fractures are well-documented complications subsequent to reverse shoulder arthroplasty (RSA), and most appear as stress fractures with no history of single trauma. To date, no study has reported the occurrence of acute displaced acromial fracture due to sudden strong deltoid contraction during heavy work. Displacement of the fracture results in a challenging surgery since it is difficult to obtain adequate fixation in thin and osteoporotic bones. We report a rare case of acute displaced acromial fracture after successful RSA treatment, using a novel technique of open reduction and internal fixation, applying two 4.5 mm cannulated screws and lateral clavicle precontoured plate.

• Proceedings of the KWS Conference
• /
• 2009.11a
• /
• pp.3-3
• /
• 2009

선박의 건조과정에서 필수적으로 선체 외판에는 선박의 안전과 운항 및 정비 등에 필요한 정보를 나타내기 위해 다양한 종류의 마크 및 문자가 마킹되어진다. 하지만, 단순한 도장 작업만으로는 해상과 같은 부식 환경에서 마크 및 문자가 쉽게 지워지거나 손상되기 때문에 마크 및 문자를 용접 비드(welding bead)로 표시하거나 미리 절단된 강판(steel plate)을 수동으로 용접한 뒤 도장을 함으로써 마크 및 문자의 손상을 방지하고 있다. 이러한 문자마킹작업을 하기 위해서는 작업자가 수작업으로 기준선과 마크 및 문자의 위치를 먹줄 등을 이용하여 마킹을 하고, 해당 마크 및 문자의 템플렛(template)을 이용하여 펀칭을 실시한 후 수동으로 용접을 실시한다. 하지만, 수작업을 통한 선체외판 문자마킹 작업은 작업자의 기량에 따라 품질이 상이하여 품질 저하의 원인이 된다. 또한 대조립 및 탑재 단계에서 문자 마킹 작업시 수직자세의 용접을 요구함으로써 작업자가 안전사고에 노출되어 있으며, 선박의 각 단계별 주요 공정보다 작업시간이 길어져 전체 선박 건조공정을 지연시키는 문제점 등을 야기시킬 수 있다. 이러한 문제점들을 해결하기 위해 조선업계에서는 선체 외판의 마크 및 문자를 자동으로 용접할 수 있는 장치를 개발하기 위해 노력해왔으며, 몇몇 개발 사례가 보고되고 있다. 하지만, 그 실효성 부분에서는 아직까지 해결하지 못한 문제점들로 인해 현장 적용에는 어려움을 보이고 있다. 본 연구에서는 선박외판 문자 자동용접장치의 기능성뿐만 아니라 현업 적용성을 가장 우선적으로 고려하여 문자마킹장치(Marking Robot for Shipbuilding) 개발을 진행하였다. 우선, 적절한 용접 재료를 선정하기 위해서 솔리드 와이어(Solid Wire)와 플럭스 코어드 와이어(Flux Cored Wire)에 대한 비드온 용접(Bead-On Welding)을 아래보기자세와 수직자세에 대해서 실시하여 적절한 용접 조건을 설정하였다. 본 연구에서 개발된 문자마킹 자동용접장치는 3축으로 구성되어 있으며 각 축들을 분리할 수 있도록 개발하여 이동성을 향상시켰으며, 작업면과 용접토치간의 거리를 일정하게 유지시킬 수 있도록 용접전류 센서(Welding Current Sensor)를 이용하여 토치 높이(Wire Extension)를 제어함으로써 균일한 품질의 용접비드를 얻을 수 있었다. 또한 문자마킹 자동용접장치는 본체 구동부와 제어부(Touch Screen)가 쉽게 분리되고 장착이 가능한 구조로 개발되었으며, 용접시 각 용접자세별로 용접전압, 전류 그리고 용접속도 설정이 가능하여 아래보기 자세뿐만 아니라 어떠한 자세에서도 같은 모양의 비드형상을 가지는 문자마킹용접이 가능하도록 개발하였으며, 이는 실험과 현장적용을 통해 검증하였다.

• Applied Biological Chemistry
• /
• v.47 no.3
• /
• pp.307-314
• /
• 2004

Specification and heavy metal contents of canned seafoods packed in oil were investigated. 30 species of canned tuna were classified by 4 groups as follow; group (sample codes, 1-10) composed of tuna and oil only, group (11-18) composed of tuna, vegetable and oil, group (19-27) composed of tuna, sauce and oil, and group (28-30) composed of tuna, vegetable, sauce and oil. Commercial canned shellfish packed in oil were mainly produced from sea mussel (sample codes, 31 and 32) and oyster (33-35). Can bodies of canned tuna were made by tin-plate, and used c-enamel or aluminium-paste as coating materials. In pH values of canned tuna, sample codes 1-10 (pH 5.55-5.69) and 19-27 (pH 5.17-5.85) were higher than sample codes 11-18 (pH 4.95-5.43) and 28-30 (pH 5.20-5.38). There was no difference in salinity (1.3-1.9%) and vacuum degree (15-18 mmHg) among canned samples. Heavy metal contents of canned seafoods ranged from 1.04-9.03 ppm for Sn, and 0.17-0.68 ppm for Pb. Those values are below the permitted range (less than 150 ppm for Sn and 2 ppm for Pb).

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.8
• /
• pp.855-860
• /
• 2011

We numerically simulated a dissolved air flotation (DAF) tank to predict the performance of the pilot facility. The flow was assumed to be two-dimensional and two-phase. The velocity distributions in the separation zones of differently shaped DAFs were compared to find the effect of the shape on the performance. The results showed that the typical flow pattern that appeared in a well-designed DAF-tank was generated in the separation zone of the base model. This flow pattern could be maintained while the baffle height was sufficiently tall regardless of the other geometric parameters. However, the baffle height and angle, the contact zone width, and the perforated plate affected the uniformity of the downward flow in the separation zone. Except for the baffle height, the base model used in this study showed a better uniformity of downward flow than did other models with different geometric parameters.

• Journal of Life Science
• /
• v.20 no.6
• /
• pp.838-844
• /
• 2010

A fibrinolytic enzyme of Streptomyces corcohrussi from soil sediment was purified by chromatography using DEAE-Sephadex A-50 and Sephadex G-50. The analysis of SDS-polyacrylamide gel suggested that the purified enzyme is a homogeneous protein and the molecular mass is approximately 34 kDa. The purified enzyme showed activity of 0.8 U/ml in a plasminogen-rich fibrin plate, while its activity in a plasminogen-free fibrin plate was only 0.36 U/ml. These results suggested that the purified enzyme acts as a plasminogen activator. The fibrinolytic activity of the enzyme under the supplementation of protease inhibitors, $\varepsilon$-ACA, t-AMCHA and mercuric chloride in the enzyme reaction was less than 24%, indicating that it could be modulated by the plasmin and/or fibrinogen inhibitors involved in the fibrinogen-to-fibrin converting process. As time passed, $Zn^{2+}$, a heavy metal ion, inhibited the activity to 34.1%. The optimum temperature of the purified enzyme was approximately $50^{\circ}C$ and over 92% of the enzyme activity was maintained between pH 5.0 and 8.0. Therefore, our results provide a potential fibrinolytic enzyme as a noble thrombolytic agent from S. corcohrussi.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.6
• /
• pp.165-178
• /
• 2011

A gigantic ship is constructed by assembling various types of ship blocks, each block being made by cutting and piecing the steel-plates together. The steel-plate piling process as the initial stage of ship construction sorts and manages the steel-plates according to the ship blocks that the steel-plates are used to make. The steel-plate piling process poses some problems such as process delay due to piling errors, safety vulnerability due to the handling of extra heavy-weight objects, and the uncertainty of work plan due to lack of information management in the pile spaces. We constructed a steel-plate piling process system based on the context-aware computing to resolve such problems. We built simulation system that can simulate the piling process and then established a smart space within the system by using tags, sensors and a real-time location system in order to collect context information. Workers receive an appropriate or intelligent service from the system.

• Journal of the Society of Naval Architects of Korea
• /
• v.43 no.3 s.147
• /
• pp.384-391
• /
• 2006

RCS effects of long-crested wave surfaces to marine targets are numerically analyzed using a 4-path model and a direct analysis method, developed based on physical optics and a combined method of physical optics/geometric optics, respectively. Reflectivity of long-crested wave surfaces is described with 'Fresnel reflection coefficients' The MPM(modified Pierson-Moskowitz) ocean spectrum is adopted to simulate long-crested waves in the direct analysis method. A numerical analysis of a benchmark model assures the validity of both methods. The direct analysis method is applied to the RCS calculation of electromagnetically large marine targets, which are vertically oriented or slanted to the long crested wave surfaces randomly generated with various significant wave heights. The long-crested wave surface much highly increases the RCS of the marine target, but those effects are decreased as the significant wave height grows up. At low elevation angle, the vertical model has entirely high RCS comparing slanted model, and the RCS of vertical flat plate is the highest on the calm sea surface, while those of slanted flat plates are the lowest on the calm sea surface. The RCS of marine targets on continuously-varying sea surface is more coherent at lower elevation angles, as well.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.2 s.35
• /
• pp.263-277
• /
• 1998

Recently, it is frequently reported that fatigue damages of deck slabs and floor systems of highway bridges occur under the conditions of increasing weight and traffic of heavy vehicles. These troubles are affected by dynamic wheel load of heavy vehicles running on roadway surface roughness with bump at expansion joint. It is required that this kind of traffic-induced vibration of highway bridges must be analyzed by using three-dimensional models of bridge and vehicle. In this study, the three-dimensional dynamic analysis is carried out, and dynamic responses of deck slab and wheel loads of moving vehicle are estimated according to different vehicle speeds and bump heights. Analytical responses of bridge deck slab are compared with experimental ones which were measured at Umeda entrance bridge of Hanshin Expressway in Osaka.