• 한국안전학회지
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• 제21권2호
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• pp.7-14
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• 2006

A Problem of low-velocity forced convection in a channel flow with heated wall is of practical importance and widely considered in the design of devices such as heat exchangers, and electronic equipments. Therefore, there is an urgent need for improving heat transfer performance of heated wall in the channel. In the present study, an oscillating vortex generator method is proposed to enhance the heat transfer in a channel. In this method, a rectangular bars are set in the upstream of heated region of the channel. The bars are forced to oscillate normal to the inflow, and then actively and largely generates transverse vortices behind the bars. As a result, this apparatus can enhance the heat transfer rates remarkably. Because of the interaction between the flow and oscillating bars, the variations of the flow and thermal fields become time-dependent state.

• Journal of Korean Neurosurgical Society
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• 제30권7호
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• pp.928-933
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• 2001

Intraventricular arachnoid cyst has been rarely reported. Here we present two cases of symptomatic intraventricular arachnoid cysts in the fourth ventricle and right lateral ventricle. The first patient was a 38-year-old female who complained of headache and left facial hypesthesia. Computed tomography and MR scan revealed large cystic lesion in the fourth ventricle. After cyst wall removal, facial hypesthesia disappeared immediately and headache improved slowly. The second patient was a 9-year-old girl who complained of headache, vomiting and paresthesia in her right low extremity. Cystic lesion in the right lateral ventricle was detected in the CT and MR scan. The symptoms improved after cyst wall removal. Surgical findings of these two cases showed that the cyst walls were attached firmly to the choroid plexus. Symptomatic intraventricular arachnoid cyst must be treated appropriately and we recommend complete cyst wall removal.

• 한국환경보건학회지
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• 제49권6호
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• pp.295-304
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• 2023

Background: Adolescents are relatively more sensitive than adults to exposure to indoor pollutants. The indoor air quality in classrooms where students spend time together must therefore be managed at a safe level because it can affect the health of students. Objectives: In this study, three types of green-wall models were applied to classrooms where students spend a long time in a limited space, and the resulting effects on reducing PM were evaluated. Methods: In the middle school classrooms which were selected as the experimental subjects, IoT-based indoor air quality monitoring equipment was installed for real-time monitoring. Three types of plant models (passive, active, and active+light) were installed in each classroom to evaluate the effects on improving indoor air quality. Results: The concentration of PM in the classroom is influenced by outdoor air quality, but repeated increases and decreases in concentration were observed due to the influence of students' activities. There was a PM reduction effect by applying the green-wall model. There was a difference in PM reduction efficiency depending on the type of green-wall model, and the reduction efficiency of the active model was higher than the passive model. Conclusions: The active green-wall model can be used as an efficient method of improving indoor air quality. Additionally, more research is needed to increase the efficiency of improving indoor air quality by setting conditions that can stimulate the growth of each type of plant.

• KIEAE Journal
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• 제12권2호
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• pp.93-101
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• 2012

In this study, we measured the Index of Greeness(I.O.G) and analyzed factors that affect in downtown street of Seoul. The aim of this article is to provide an ways of improving I.O.G, with an emphasis on accuracy of measurement. We utilized the autimatic measurment techniques proposed by Tonosaki to solve the problem of accuracy in measurement. The result is as follows : Firstly, the average I.O.G of Gwanghwamun Plaza is 15.76%, Jongno is 11.48% and Dasanro(from Yaksu station to Beotigogae station) is 6.36%. According to the comprehensive analysis in three reseach areas, it shows that I.O.G is intimately linked with planting method, species of trees and the presence of wall planting. Secondly, it was analyzed that grass and ground-cover planting promote I.O.G better than other method. The I.O.G of photo which contains grass is 45.47%. According to the comparative analysis between tree planting and multi-planting method, the presence of lower planting showed a difference about 8.77% of I.O.G.. From the persipective of I.O.G, tree planting with two lines is more effective than one. The difference of two ways is about 3.24%. Thirdly, it is an efficint way to use the wall planting or vertical planting in order to promote I.O.G.. In Dasanro, The I.O.G of photo which contains wall planting or vertical planting is 45.47% in contrast to the average of I.O.G. is 6.36%. Fourthly, the difference of I.O.G between broadleaf tree and needleleaf tree was larger than we thought. If look closely confined to this study, the I.O.G of street planted by Pine is 3.61% and Eastern Sycamore Family Bottonwood is 12.55%.

• Journal of Gastric Cancer
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• 제20권1호
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• pp.72-80
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• 2020

Purpose: Proximal gastrectomy (PG) is a function-preserving surgery in cases of proximally located early-stage gastric cancer. Because gastroesophageal reflux is a major pitfall of this operation, we devised a modified esophagogastrostomy (EG) anastomosis to fix the distal part of the posterior esophageal wall to the proximal part of the anterior stomach wall to produce an anti-reflux mechanism; we named this the SPADE operation. This study aimed to show demonstrate the clinical outcomes of the SPADE operation and compare them to those of previous PG cases. Materials and Methods: Case details of 56 patients who underwent PG between January 2012 and March 2018 were retrospectively reviewed: 30 underwent conventional esophagogastrostomy (CEG) anastomosis using a circular stapler, while 26 underwent the SPADE operation. Early postoperative clinical outcome-related reflux symptoms, endoscopic findings, and postoperative complications were compared in this case-control study. Results: Follow-up endoscopy showed more frequent reflux esophagitis cases in the CEG group than in the SPADE group (30% vs. 15.3%, P=0.19). Similarly, bile reflux (26.7% vs. 7.7%, P=0.08) and residual food (P=0.01) cases occurred more frequently in the CEG group than in the SPADE group. In the CEG group, 13 patients (43.3%) had mild reflux symptoms, while 3 patients (10%) had severe reflux symptoms. In the SPADE group, 3 patients (11.5%) had mild reflux symptoms, while 1 had severe reflux symptoms (absolute difference, 31.8%; 95% confidence interval, 1.11-29.64; P=0.01). Conclusions: A novel modified EG, the SPADE operation, has the potential to decrease gastroesophageal reflux following a PG.

• 한국재료학회지
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• 제12권7호
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• pp.587-590
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• 2002

A silver indium sulfide ($AgInS_2$) epilayer was grown by the hot wall epitaxy method, which has not been reported in the literature. The grown $AgInS_2$ epilayer has found to be a chalcopyrite structure and evaluated to be high quality crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks are ascribed to the band-to-band transition. The valence band splitting of $AgInS_2$ was investigated by means of the photocurrent measurement. The crystal field splitting, $\Delta_{cr}$ , and the spin orbit splitting, $\Delta_{so}$ , have been obtained to be 0.150 eV and 0.009 eV at 10 K, respectively. And, the energy band gap at room temperature has been determined to be 1.868 eV. Also, the temperature dependence of the energy band gap, $E_{g}$(T), was determined.d.

• Archives of Plastic Surgery
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• 제38권3호
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• pp.228-234
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• 2011

Purpose: Reconstruction of chest wall has always been a challenging problem. Muscle flaps for chest wall reconstruction have been helpful in controling infection, filling dead space and covering the prosthetic material in this challenge. However, when we use muscle flaps, functional and cosmetic donor site morbidities could occur. The authors applied and revised various partial muscle flaps and combination use of them to cover the prosthetic material for the chest wall reconstruction and evaluated the usefulness of partial muscle flaps. Methods: This study included 7 patients who underwent chest wall reconstruction using partial muscle flap to cover prosthetic material from 2004 to 2008. The pectoralis major muscle was used in anterior 2/3 parts of it leaving lateral 1/3 parts of it. The anterior 2/3 parts of the pectoralis major muscle were used while lateral 1/3 parts were left. In case of the rectus abdominis muscle flap, we used upper half of it, or we dissected it around its origin and then advanced to cover the site. The latissimus dorsi muscle flap was elevated with lateral portion of it along the descending branch of the thoracodorsal artery. If single partial muscle flap could not cover whole prosthetic material, it would be covered with combination of various partial muscle flaps adjacent to the coverage site. Results: Flap coverage of the prosthetic material and chest wall reconstructions were successfully done. There occurred no immediate and delayed post operative complications such as surgical site infection, seroma, deformity of donor site and functional impairment. Conclusion: When we use the muscle flaps to cover prosthetic material for chest wall reconstruction, use of the partial muscle flaps could be a good way to reduce donor site morbidity. Combination of multiple partial flaps could be a valuable and good alternative way to overcome the disadvantages of partial muscle flaps such as limitation of volume and size as well as flap mobility.

• 한국전기전자재료학회논문지
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• 제27권4호
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• pp.221-225
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• 2014

In modern times, threat of high power electromagnetic wave is increasing. When the electrical grid and communication network are attacked by these high power electromagnetic wave, the whole infrastructure is paralyzed. To protect the infrastructure from these high power electromagnetic wave threat, the shielding facility that can block high power electromagnetic wave is constructed. Also shielding effectiveness evaluation about the constructed facility is important. But, because of space efficiency and saving of construction cost to construct the actual shielding facility, the shielding room wall is generally adjacent to exterior concrete structures. As space between shielding facility wall and concrete structures is very small, arranging the transmitting antenna exterior shielding facility is realistically difficult. Therefore, in this research, The shielding effectiveness measurement plan in the state of exterior narrow space of HEMP shielding facility is presented. And to apply this plan, The influence of shielding effectiveness according to the size of the shielding facility is analyzed.

• 한국주거학회논문집
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• 제26권6호
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• pp.139-146
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• 2015

In this study, the plane type of main building relics of unified Silla period house site which excavated in Gyeongju city after 1990s was classified and the architectural characteristic of them was investigated. The chronology of building relics in Silla capital city site was mostly known as 8-9th century, and by standard of column arrangement, the plane types of them could be classified as grid type, front veranda-grid type, outer column type. The outstanding characteristic of plane is wide span and open front veranda. In most relics the span were over 4 meters, and inner foundations for small post and strip foundation were found between columns. The front veranda added type buildings were composited of enclosed main room and open front veranda, and column arrangement of them dose not fall into line in most case. Thus it thought that the structures of enclosed main room and open front veranda were independent. The interior space of enclosed main room were divided two rooms by partition wall in some case. In this case, one room is enclosed by wall, and the other room has open front side. This plane is considered for the pleasant life in cold winter and hot summer.

• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.867-872
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• 2009

In centrifugal oil filters particles are forced to move toward the filter casing wall by centrifugal force in the rotating oil flow and the particles are trapped and removed on the filter paper installed at the wall. In the present study, flow field of oil and particle motion in a centrifugal oil filter has been numerically calculated in order to estimate the filtering efficiency for various operating conditions. Fluent code was used for the numerical calculations. Uncoupling the oil flow and the particle motion and the use of particle tracking trajectory enabled the estimation of filtering efficiency for various particle sizes, particle density and the filter rotational speed. Higher filtering efficiency was observed for heavier and larger particles as well as higher filter rotational speed. For the typical case of the particle density of $6000kg/m^3$ and the particle size of $10{\mu}m$ at 3500 RPM, the calculated filtering efficiency per passage was 0.31.