• Bulletin of the Korean Chemical Society
• /
• 제35권2호
• /
• pp.353-356
• /
• 2014

We fabricated organic photovoltaic (OPV) based on ZnO ripple structure on indium tin oxide as electron-collecting layers and PTB7-F20 as donor polymer. In addition, atomic layer deposition (ALD) was used for preparing additional ZnO layers on rippled ZnO. Addition of 2 nm-thick ALD-ZnO resulted in enhanced initial OPV performance and stability. Based on photoluminescence results, we suggest that ALD-ZnO layers reduced number of surface defect sites on ZnO, which can act as electron-hole recombination center of OPV, and increased resistance of ZnO towards surface defect formation.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
• /
• pp.305-306
• /
• 2002

In this paper, the endurance life of the rolling bearings with defective balls and their failure (flaking) phenomena are presented. It was found that the lives of ball bearings with defective balls were shorter than that of calculated L10 life as well as that of normal bearings in spite of the using standard bearing components. Although the bearings were assembled with defective balls, whereas the other parts were qualified new ones, the main failures were occurred on the inner ring raceways. Moreover, the failures were on the center of the groove curvature and the severity of failure is similar to the order of initial defect depth of the balls. These shows that the defects on the bearings can affect the life of tribologically contacted mating parts.

• Journal of Chest Surgery
• /
• 제24권2호
• /
• pp.212-216
• /
• 1991

A surgical correction was successfully performed in a adult female who had pulmonary atresia with almost non-confluent pulmonary artery, PDA and ventricular septal defect. Initially as a first stage of corrective surgery isolation of patent ductus arteriosus, ligation of aortopulmonary collaterals and identification of the pathologic anatomy of left pulmonary artery through left posterolateral approach were performed. At the second stage, a week after the initial operation, total correction was done making both pulmonary arteries confluent with albumin coated woven-dacron graft, external valved conduit and closure of large VSD of subarterial and perimembranous type. The PDA was ligated with previously encircled heavy stitch soon after partial bypass was started. Although massive bleeding from anastomotic site of dilated left pulmonary artery to the graft occurred preoperatively, postoperative functional improvement was excellent in terms of disappearance of cyanosis and normal exercise tolerance.

• Corrosion Science and Technology
• /
• 제14권6호
• /
• pp.253-260
• /
• 2015

The pitting behaviours of 304L and 316L stainless steels were investigated at $3^{\circ}C$ to $90^{\circ}C$ in 1 M solutions of NaCl, NaBr and NaI by potentiodynamic polarization. The temperature dependences of the pitting potential varied according to the anion, being near linear in bromide but exponential in chloride. As a result, at low temperatures grades 304L and 316L steel are most susceptible to pitting by bromide ions, while at high temperatures both stainless steels were more susceptible to pitting by small chloride anions than the larger bromide and iodide. Thus, increasing temperature appears to favour attack by smaller anions. This paper will attempt to rationalise both of the above findings in terms of the point defect model. Initial findings are that qualitatively this approach can be reasonably successful, but not at the quantitative level, possibly due to insufficient data on the mechanical properties of thin passive films.

• Archives of Reconstructive Microsurgery
• /
• 제23권2호
• /
• pp.45-50
• /
• 2014

Palmar soft tissue defects are best reconstructed using a replacement flap of proper size with adequate soft tissue stability for mechanical resistance as well as with protective sensation. Reconstructive approaches are dictated by injury mechanism, defect size and location, and the status of the wound bed and tendino-skeletal structure. While uninjured portions of the hand can be used as a source for local flaps, the use of free flaps allows for maximal access for selection of the most ideal replacement tissue for the defect to be restored as close to the initial state as possible. Here, we review the garden variety of free flaps used in reconstruction of palmar soft tissue defects.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2009년도 제7회 압연 심포지엄
• /
• pp.73-76
• /
• 2009

Increase in tensile strength of steel is important for fuel efficiency and $CO_2$ reduction. But the higher the strip strength, the more defect could be generated in hot strip mill. This study focuses on line-type edge scab. One of the causes for the defect is initial edge cracks commonly observed on a slab but their correlation has not been verified yet. Thus, the objective of this report is to verify if the edge crack is exactly the seed for edge scab. For this, we conducted pilot hot rolling test with cracked slab and compared the development of cracks and edge scabs on hot-rolled strip.

• 소성∙가공
• /
• 제8권5호
• /
• pp.482-490
• /
• 1999

7000 series Al alloy with good mechanical properties has been focused with tendency to reduce the components weight of aircraft and automobile. However, it is difficult to manufacture a sound extruded product because of segregation, grain growth, casting defect, surface defect, decreasing extrudability and so on. The objective of this study is to manufacture a new 7000 al alloy more than the extrudability of A7N01 and A7003 through controlling the weight (%) Mg, Zn, Si. Hot extrusion experiments on the axisymmetric rod are performed in 500℃ and also performed analysis of the same process using unmerical analysis method, a coupled rigid-thermoviscoplastic finite element method. Extrusion limit diagram was obtained for the developed alloy by FE-simulation in order to define the relationship of extrusion speed and initial billet temperature.

• 대한전자공학회논문지
• /
• 제24권3호
• /
• pp.517-526
• /
• 1987

This paper proposes a new testable design for Zipper CMOS circuits. This design provides an additional feedback loop (called self oscillation loop) whichin the circuit, for testability. The circuit is tested only by observing the oscillation on the loop. The design can be applied to the multistage as well as the single stage, and can detect multiple faults which are undetectable by the conventional testing method. The application and evaluation of test patterns become easy and fault-free responses are not necessary. If the conventional testing method is applied to the sequential Zipper CMOS circuit with the LSSD design technique, it has the serious defect that the initial value may change due to intermediate test patterns and much time taken to apply the necessary test patterns. By using the proposed design, however, the sequential Zipper CMOS circuit with the LSSD design technique can be easily tested without such a defect. Also, the validity of the design is verified by performing the circuit level simulation.

• 국제강구조저널
• /
• 제18권4호
• /
• pp.1098-1106
• /
• 2018

The object of this study is to clarify fatigue limit and fatigue crack growth characteristic of SBHS700 base metal which is 780 MPa class steel. This study carried out the fatigue tests of SBHS700 base metal containing different defect size, and the fatigue limit was compared with that of the conventional steel. Test results indicate that the fatigue limit increased with decrease initial defect size, and can be precisely evaluated by using ${\sqrt{area}}$ parameter model. This paper also presents that crack growth characteristic was almost the same as that of the conventional steel from the observation of striations by using Scanning electron microscope and length of beach marks.

• Journal of Chest Surgery
• /
• 제25권1호
• /
• pp.23-31
• /
• 1992

The ideal approach in the staged management of patients with pulmonary atresia has been a challenging problem and the result has not been always satisfactory. We reviewed our early result of initial palliative surgeries in fifteen cases of pulmonary atresia with interventricular communication Included are eight cases of simple pulmonary atresia with ventricular septal defect and seven cases of pulmonary atresia associated with other complex cardiac anomalies. The ages of the patients were less than one year except one. The morphology of pulmonary vasculature was highly variable and showed unfavorable conditions in most cases. Pulmonary artery was nonconfluent in two. Two-thirds of all cases showed significant problems such as juxtaductal stenosis or diffuse hypoplasia. The ductus arteriosus usually narrowed at its pulmonic end. Initial palliation was done by modified Blalock-Taussig shunt in six, central shunt with or without pulmonary angioplasty in five, right ventricular outflow tract [RVOT] reconstruction in three and direct connection of nonconfluent pulmonary arteries with bilateral cav-opulmonary shunt in one patient. There were 3 hospital deaths. Two of them underwent simultaneous repair of the associated anomaly of TAPVR. Among the six patients who received modified Blalock-Taussig shunt, three needed early second palliative procedure by central shunt, RVOT patch reconstruction and pulmonary angioplasty in each case, All patients who received central shunt showed marked clinical improvement. Among the twelve patients who survived the palliative procedures, two patients underwent total correction 13 months and 18 months after initial palliation respectively. We think that the choice of palliative procedure must be individualized according to the morphology of the pulmonary arteries. More experience and long term follow-up data are necessary to meet this challenging problem.