• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.525-529
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• 1999

A cone shape drum polisher was developed to make up for the demerits of conventional CMP apparatus. The developed equipment has several superiorities. First of all, it can achieve uniform velocity profile on all the contact line because of its shape and easy to control the amount of slurry at the position of use. The whole area of wafer surface is exposed to the visual area except the contact line between wafer and drum, hence we can detect polishing end point more easily than any other polishing equipments. Also it has additional merits such as small foot print and polishing load. Polishing characteristics were investigated by developed equipment.

• Imaging Science in Dentistry
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• 제45권3호
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• pp.181-185
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• 2015

Numerous cases of enamel renal syndrome have been previously reported. Various terms, such as enamel renal syndrome, amelogenesis imperfecta and gingival fibromatosis syndrome, and enamel-renal-gingival syndrome, have been used for patients presenting with the dental phenotype characteristic of this condition, nephrocalcinosis or nephrolithiasis, and gingival findings. This report describes a case of amelogenesis imperfecta of the enamel agenesis variety with nephrolithiasis in a 21-year-old male patient who complained of small teeth. The imaging modalities employed were conventional radiography, cone-beam computed tomography, and renal sonography. Such cases are first encountered by dentists, as other organ or metabolic diseases are generally hidden. Hence, cases of amelogenesis imperfecta should be subjected to advanced diagnostic modalities, incorporating both dental and medical criteria, in order to facilitate comprehensive long-term management.

• Imaging Science in Dentistry
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• 제50권4호
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• pp.377-384
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• 2020

This report presents 2 cases of sinus fungus ball and describes the characteristic radiographic features of fungus ball in the maxillary sinus. Two female patients, aged 62 and 40 years, sought consultations at a dental hospital for the treatment of dental implants and tooth pain, respectively. Panoramic radiography and small field-of-view(FOV) cone-beam computed tomography (CBCT) did not provide detailed information for the radiographic diagnosis of fungus ball due to the limited images of the maxillary sinus. Additional paranasal sinus computed tomographic images showed the characteristic features of fungus ball, such as heterogeneous opacification and intralesional calcification of the maxillary sinus. The calcified materials of the fungus balls were located in the middle and superior regions of the maxillary sinus. It is necessary to use large-FOV CBCT for the detection of calcified materials in the upper maxillary sinus to confirm the diagnosis of fungus ball.

• 대한토목학회논문집
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• 제38권3호
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• pp.429-438
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• 2018

원추형콘과 T-bar 관입시험기는 점토의 비배수전단강도를 측정하기 위해 널리 사용된다. 축소모형시험의 경우 소형관입시험기가 사용되어야 하지만 경험상관계수에 대해 발표된 자료가 부족하다. 본 연구에서는 소형콘과 소형T-bar 관입시험기의 경험상관계수를 도출하기 위한 시험시스템을 구축하였고, 카올린점토에 대하여 실험을 수행하였다. 직경 350mm의 강재원형챔버를 사용하여 4개의 모형지반을 조성하였고, 각 모형지반은 다른 선행압밀응력에서 압밀하여 비배수전단강도를 조절하였다. 경계면 효과, 관입속도, 직경 및 형상의 영향을 확인하기 위하여 다른 직경을 가진 두 직경의 소형콘(10mm, 16mm)과 직경 10mm T-bar를 이용하여 시험을 수행하였다. 또한 관입시험 후의 시편을 채취하여 비압밀비배수삼축시험을 수행하여 비배수전단강도로 결정하였다. 최종적으로 비배수전단강도와 관입시 선단저항력의 상관관계를 통해 경험상관계수를 산정하였다.

• Journal of Biosystems Engineering
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• 제20권4호
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• pp.313-322
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• 1995

This study was conducted to find the design factors of spraying device of the boom sprayer for low volume application. Specific objectives of this study were 1) to select proper nozzles for broadcast spraying and row crop spraying by the nozzle spray characterisic experiment, and 2) to investigate the coverage characteristic of rice plant at the row crop spraying. The results of this study are summarized as follows. (1) From the tested results on the droplet diameter spectrum and spray pattern the standard flat-fan nozzle and drift guard nozzle were judged as appropriate for the broadcasting. Even flat-fan nozzle showed similar span values to standard flat-fan nozzles and drift guard nozzle : however, the nozzles were found to be inappropriate for broadcasting because of their spray pattern. Hollow cone nozzle showed relatively small span values and uniform spray pattern. (2) For the upper and lower sides of the rice plants, coverage rates of even flat-fan nozzles and hollow cone nozzles were maximum at the second row, but decreased rapidly after the third row. For the middle side of the rice plants, coverage rates of them were maximum at the first row, but decreased rapidly. When one nozzle was tested, C.V. values were in the range of 90~160% and 60~160% on entire heights of rice plant for even flat-fan nozzles and hollow cone nozzles respectively. C.V. values at other parts were poor. Spray coverage rate at the middle part was improved by overlapping the nozzles whereas there was little difference on the upper and lower part of rice plants. (3) For spraying lower part of rice plant between rows, even flat-fan nozzles and hollow cone nozzle were judged as appropriate, but in order to ensure the uniform coverage, distance between nozzles, recommended to be less than 90cm.

• 한국지반신소재학회논문집
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• 제16권4호
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• pp.1-11
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• 2017

본 연구에서는 헬리컬 파일의 관입시간과 극한하중에 관한 연구를 진행하고자 1/6 축소모형 실험을 진행하였다. 균질한 상대밀도의 사질토 지반을 형성하기 위하여 강사법을 사용하였다. 실험 조건으로 헬리컬 파일의 나선형 원판(heilx plate) 간격을 50mm와 150mm 두 Type으로 제작하였고, 헬리컬 파일의 회전관입 시 회전속도를 15rpm과 30rpm으로 진행하였다. 관입 완료된 헬리컬 파일에 콘 장비를 항타하여 관입하였다. 콘 장비 관입으로 헬리컬 파일의 극한하중 증가와 폐색의 정도를 확인 할 수 있었다. 위의 실험 결과를 토대로 헬리컬 파일의 관입시간은 "회전속도 30rpm-나선형 원판 간격 50mm"에서 단축 되었고, 극한하중은 "회전속도 30rpm-나선형 원판 간격 150mm-콘 장비 유"인 조건에서 높은 극한하중을 보였다.

• Imaging Science in Dentistry
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• 제53권4호
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• pp.345-353
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• 2023

Purpose: The objective of this study was to propose a method for developing a clinical phantom to reproduce various diseases that are clinically prevalent in the field of dentistry. This could facilitate diverse clinical research without unnecessarily exposing patients to radiation. Materials and Methods: This study utilized a single dry skull, which was visually and radiographically examined to evaluate its condition. Existing lesions on the dry skull were preserved, and other relevant lesions were artificially created as necessary. These lesions were then documented using intraoral radiography and cone-beam computed tomography. Once all pre-existing and reproduced lesions were confirmed by the consensus of 2 oral and maxillofacial radiologists, the skull was embedded in a soft tissue substitute. To validate the process, cone-beam computed tomography scans and panoramic radiographs were obtained of the fabricated phantom. All acquired images were subsequently evaluated. Results: Most lesions could be identified on panoramic radiographs, although some sialoliths and cracked teeth were confirmed only through cone-beam computed tomographic images. A small gap was observed between the epoxy resin and the bone structures. However, 2 oral and maxillofacial radiologists agreed that this space did not meaningfully impact the interpretation process. Conclusion: The newly developed phantom has potential for use as a standardized phantom within the dental field. It may be utilized for a variety of imaging studies, not only for optimization purposes, but also for addressing other experimental issues related to both 2- and 3-dimensional diagnostic radiography.

• 상하수도학회지
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• 제21권1호
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• pp.47-55
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• 2007

The waste water treatment facility at rural and mountainous region in catchment areas of dams should be small scale. The wastewater treatment facility of small scale has some specification as follows;1)simple process, 2)low maintenance cost, and 3)high removal efficiency. So, we developed the bioreactor which can be satisfied with the specification of small scale waste water treatment facility. The bioreactor consisted of the anoxic and oxic zone. The two zones were effectively separated by cone type baffle. By the effective separation through CTB, the nitrification and denitrification reaction occurred effectively. Therefore, the removal efficiency of total nitorgen (TN) increased compared to other types of baffle. And, we put into the bio activated media in oxic zone to increase the concentration and activity of microbiology. The media contained the components which were made of many kinds of the minerals to increase the activity of microbiology. Additionally, we observed that the phosphate removal efficiency increased by bio activated media. This is resulted from the coagulation-sedimentation reaction by mineral in components. The average removal efficiencies of TN and TP during Run 2 were 69 and 89% which were 4 and 25% higher than those during Run 1 without the MA, respectively. For BOD, COD, SS and TKN, the average removal efficiencies at Run 2 were slightly higher than those at Run 1. Therefore, we could maintain the high concentration and high activity of microbiology through bioreactor developed in this study. And the removal efficiency of TN and TP increased.

• 한국염색가공학회지
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• 제26권1호
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• pp.45-52
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• 2014

Red pine (Pinus densiflora) is widely used traditional medicine, pharmacological and nutritional values from which the phytochemical compounds are derived. The present study was aimed to examine the antibacterial effects in the absence and presence of a immature red pine cone extract against 13 microorganisms. The components in the aqueous extract from immature red pine cone were identified by GC-MS. About 1.4% of total polyphenolic compound was measured in aqueous extract collected from immature red pine cone. Also, the high concentration of ${\beta}$-phellenandrene, ${\alpha}$-pinene, limonene, bornyl acetate and aldehyde was detected in total ion chromatograms. Of total 13 microorganisms, 4 microorganisms including Pseudomonas aeruginosa, Vibrio cholera, Listeria monocytogenes, Klebsiella pneumonia were effectively killed by aqueous extract of immature red pine cone. The highest anti-bacterial effect was detected in P. aeruginosa, followed by V. cholera, L. monocytogenes and K. pneumonia. In case of P. aeruginosa, the largest diameter of inhibition zone was maintained to 1/2 solution treated cells and slightly decreased at 1/4 and 1/8 solution treated cells. Also, in test used V. cholera and L. monocytogenes, the inhibition zone was strongly formed in only 1 and 1/2 solution treated cells, while K. pneumonia showed the very small diameter of inhibition zone in all concentrations. Therefore, these results suggested that the aqueous extracts of immature red pine cone should be considered as a new and potentially important anti-bacterial substrate to effectively prevent the microbial infection and penetration.

• 한국자원식물학회지
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• 제24권1호
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• pp.69-75
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• 2011

우리나라 가문비나무 천연집단의 구과, 종자 및 발아특성에 대한 집단간 및 집단내 개체간 변이를 조사하였다. 지리산과 덕유산 집단의 25개 개체목에서 구과를 채취하여 13가지 구과 및 종자특성과 3가지 발아특성에 대하여 분석하였다. 분산분석 결과 종자의 폭 및 무게, 종자날개지수 및 평균발아일수 특성을 제외한 9개 형질들에서 집단간 및 집단내 개체간에 유의적인 차이가 인정되었다. 변이계수 값은 구과와 종자의 무게, 충실율, TTC, 발아율 및 발아속도 형질들에서 29.7%~57.1% 범위의 높은 값을 보였으며, 나머지 형질들에서는 10% 내외의 비교적 변이가 작은 것으로 나타났다. 대체적으로 형태적 특성은 지리산집단의 경우 구과 및 종자날개가 작으며 긴 경향을 보인반면 덕유산 집단이 종자가 크고 긴 형태를 나타냈다. 종자충실율과 TTC 활력은 지리산 집단이 덕유산 집단에 비해 각각 1.79배, 1.87배 정도 우수한 집단간 차이를 나타냈다. 가문비나무의 종자발아에 미치는 온도조건의 영향을 보면 발아적온은 $20^{\circ}C$였으며, 이때의 평균발아일수는 7.5일, 발아속도는 2.9개/일로 나타났다. 지리산 집단의 경우 평균발아율이 40.7%, 발아속도가 0.90개/일로서 덕유산 집단(17.7%, 0.37개/일)보다 발아특성이 우수한 것으로 나타났다. 그러나 구과, 종자 및 발아특성에 대한 상관분석 결과 국내 가문비나무 천연집단은 종자활력이 한정된 분포에 따른 근친교배 및 특정 개체의 편중개화 현상에 많은 영향을 받는 것으로 추정되어 소멸을 초래할 가능성이 매우 높은 것으로 나타났다.