• Proceedings of the Membrane Society of Korea Conference
• /
• 1993.10a
• /
• pp.68-73
• /
• 1993

여과포에 의한 분진 포집기술은 다른 분진포집기술에 비해 가장 우수한 집진성능을 나타낼수 있는 집진기술로서 최근에 와서는 분진발생공정, 연소설비 및 폐기물 소각설비의 중금속 물질, 유해 기체 및 분진의 동시포집 적용 등 광범위한 산업분야에 적응되어 운전되고 있다. 배출기체의 악조건과 습도가 다량 함유된 조건에서는 여과포 집진장치의 적용이 어렵다고 생각되고 있지만, 처리 기체의 조건 및 포집분진의 특성에 적합한 여과포의 개발과 탈진방식(cleaning method)의 개선으로 인해 해결이 가능하게 되었다. 또한 여과포에 의한 분진포집기술은 장치를 통과하는 배출기체의 속도가 다른 집진기술에 비해 느려 여과포 면적이 상대적으로 넓어져서 장치의 설치면적이 많이 소요된다는 단점이 있으나, 여과포를 원간으로 봉재하여 서로 접근시켜 많은 갯수를 다단으로 배치함과 동시에 연속탈진시스템(on-line cleaning)을 채택함으로써 장치에 소요되는 면적을 최소한으로 줄이려는 연구가 계속되고 있다. 대체적으로 여과포에 의한 분진포집기술의 산업체 적용에서 장치의 압력손실은 약 100 - 100 $mmH_2O$ 정도의 범위가 대부분이고 분진 포집효율은 거의 99.9%에서 99.99% 정도 달성이 가능하다[1,2,3].

• Journal of the Korean Society of Propulsion Engineers
• /
• v.7 no.4
• /
• pp.10-18
• /
• 2003

In the present study, several different types of PSD performance test systems were reviewed. Basically there are two methods to pulsate the system; whole-feeding-system pulsation and working-fluid pulsation. The latter method adopts either a piston-type pulsator or a restrict-type pulsator The working-fluid pulsation using a restrict-type pulsator was considered to be the most appropriate experimental system to study the effects of the primary parameters, and a practical design of the system was proposed.

• Aerospace Engineering and Technology
• /
• v.5 no.2
• /
• pp.181-187
• /
• 2006

The present study deals with the experimental facility for PSD (POGO Suppression Device) performance test systems. Basically there are two methods to pulsate the system; whole-feeding-system pulsation and working-fluid pulsation. The latter method adopts either a piston-type pulsator or a restrict-type pulsator. The working-fluid pulsation using a restrict-type pulsator was considered to be the most appropriate experimental system to study the effects of the primary parameters, and a practical design of the system was proposed. Also, the experimental facility adopts the ball valve type pulsator considering the leak problem of the plate type pulsator.

• The Journal of the Korea Contents Association
• /
• v.18 no.11
• /
• pp.508-515
• /
• 2018

The purpose of this study was to analyze the errors of the built - in dose area product and the calibrated moving dose area product when using automatic exposure controller of the interventional equipment. And then, the importance of the dosimeter calibration and the necessity of the calibration guideline were investigated. The experimental method was to assemble the phantom into Thin, Normal, and Heavy Adult according to the NEMA Phantom manual and to measure the dose area with the built-in dose area product and the moving dose area product. As a result, in all thicknesses, the built-in dose area product showed higher doses than the moving dose area product, and the thicker the thickness, the larger the difference. In addition, paired t-test was performed for each item and there was a significant difference in each item between p<0.05. In conclusion, considering the intervention which is highly exposed to the radiation exposure, it is that we have to know the accurate dose when using the AEC of the equipment. And there is no calibration guide for the built-in dose area meter, thus calibration guidelines should be prepared.

• The korean journal of orthodontics
• /
• v.40 no.3
• /
• pp.176-183
• /
• 2010

Objective: This study was performed to evaluate functional changes of occlusion after orthodontic treatment by measuring the occlusal force (OcFr) and occlusal contact area (OcAr), and to compare OcFr and OcAr change according to premolar extractions. Methods: Data were obtained from 74 patients who had finished orthodontic treatment using fixed appliance aged between 18 and 40 years. Subjects were divided into groups who had four premolars extractions or non-extraction (Male extraction-16, Male nonextraction-18, Female extraction-19, Female nonextraction-21). All subjects were asked to bite pressure-sensitive sheets into maximum intercuspation with maximum bite force, and OcFr and OcAr were evaluated by measuring the sheet with a CCD camera. Records were taken right after debonding, 1 week, 1 month, 3 months, 6 months and 1 year after debonding. Results: OcFr and OcAr increased gradually in all groups during the 1 year retention period (p < 0.05). Male groups showed higher OcFr and OcAr than female groups throughout the retention periods (p < 0.05). There were no statistically significant differences of OcFr and OcAr between extraction and non-extraction groups in both males and females (p > 0.05). Conclusions: Occlusion was improved functionally throughout the 1 year retention, and premolar extraction did not induce a decline in the functional aspect of occlusion.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.6
• /
• pp.703-712
• /
• 2019

In this study, capability of an air slot in a siphon spillway for controlling outflow discharge is investigated through hydraulic experiments. Arc and rectangular shapes of air slot are considered and the open area of air slot can be varied. Complex air-regulated flow occurs inside of the siphon spillway when the air slot is installed on it. The same discharge is measured at the same water level inside the reservoir when the water level rises or falls. Nondimensional discharge through the siphon spillway decreases as nondimensional open area of the air slot increases when head differences and water levels of reservoir are constant. The hydraulic experiments show that the control of outflow discharge of siphon spillway is possible by controlling the open area of the air slot.

• Journal of Digital Convergence
• /
• v.15 no.10
• /
• pp.307-314
• /
• 2017

In this study, a minimum amount of the vertical occlusion was secured differently in each type of mandibular advance devices snoring and Class I malocclusion patients wore these devices. This study analyzes, after the use of devices, a different amount of the vertical occlusion results in a change of the area of upper airway by additional changes such as mandibular position, muscle changes, tongue position. The higher the vertical amount, the area of the upper airway was shown smaller, And if the patient's tongues was prevented from the distal movement, the area of the upper airway had increased, To reduce snoring, doctors should accurately diagnose patients' occlusal relationships and select a MAD snoring that is appropriate for the occlusion. The dental technician who builds the selected device should also consider design settings such as the amount of vertical occlusion, the finish lines, and the thickness of the device to increase the effectiveness of the device.

• Korean Journal of Materials Research
• /
• v.6 no.1
• /
• pp.3-11
• /
• 1996

대면적 정전 접합 장치를 고안 및 제작하여 Si과 glass를 정전 접합시켰다. 여러 온도에서 정전 접합 후 접합 면적을 측정하였으며 접합이 이루어진 경우 그 접합 면적이 90%를 넘었다. 접합시 전류를 측정하여 접합 강도와의 관계를 살펴보였다. 잔류 공공을 생성시키는 원인은 재료의 표면 거칠기 차이나 전극의 모양보다는 불순물 입자에 의한 것임이 밝혀졌고 같은 크기의 불순물 입자에 대한 공공의 크기는 접합 온도가 높을수록 감소하였다. 정전 접합에 미치는 불순물의 영향을 공공의 크기 및 불순물 입자의 크기를 측정하여 살펴보았다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.6
• /
• pp.1054-1062
• /
• 2022

The population of Korea's solar salt-producing regions is rapidly aging, resulting in a decrease in the number of productive workers. In solar salt production, salt collection is the most labor-intensive operation because existing salt collection vehicles require human operators. Therefore, we intend to develop an unmanned solar salt collection vehicle to reduce manpower requirements. The unmanned solar salt collection vehicle is designed to identify the salt collection status and location in the salt plate via color detection, the color detection performance is a crucial consideration. Therefore, an image processing algorithm was developed to improve color detection performance. The algorithm generates an around-view image by using resizing, rotation, and perspective transformation of the input image, set the RoI to transform only the corresponding area to the HSV color model, and detects the color area through an AND operation. The detected color area was expanded and noise removed using morphological operations, and the area of the detection region was calculated using contour and image moment. The calculated area is compared with the set area to determine the location case of the collection vehicle within the salt plate. The performance was evaluated by comparing the calculated area of the final detected color to which the algorithm was applied and the area of the detected color in each step of the algorithm. It was confirmed that the color detection performance is improved by at least 25-99% for salt detection, at least 44-68% for red color, and an average of 7% for blue and an average of 15% for green. The proposed approach is well-suited to the operation of unmanned solar salt collection vehicles.

• Membrane Journal
• /
• v.13 no.1
• /
• pp.20-28
• /
• 2003

In this study, we try to formularize simultaneous equations to make a prediction about pressure drop for designing intravascular artificial lung assist device. Designing parameters to predict the effect of pressure drop and designed modules under various conditions were studied through an experimental modeling before inserting the artificial lung assist device into as venous. We measured pressure drop in various number of hollow fiber membranes, when the inside diameter of shell is fixed in 3 cm, and tried to develope the prediction equations by curve fitting based on the correlation between the experimental pressure drop and the device frontal area or packing density. The results showed that pressure drop increased with 2nd order functional formula as the liquid flow rate, the frontal area, and the packing density increased. Also, we can estimate the pressure drop as a function of the frontal area or packing density. The pressure drop obtained from the experiment was similar to that from the equation, confirming the usefulness of the equation.