• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.13 no.1
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• pp.127-137
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• 1983

The aim of this study was to establish the diagnostic criteria of normal submandibular glands in adults. Materials included 132 sialograms of selected person from 23 to 28 years of age. In subjects each variable was measured and evaluated statistically introducing 18 items respectively. Conclusions from this study were as follows. 1. The mean diameter of main duct was 1.96㎜ in distal end and 2.71㎜ in hilar end, so the diameter of distal end was smaller than that of hilar end in submandibular glands. 2. The mean length of main duct was 42.02㎜ in submandibular glands. 3. The mean angle of main duct was 35.67 degrees with inferior border of mandible and 103.05 degrees at posterior mylohyoid portion. 4. In configurations following shape of main duct, those revealed that 39.39% of cases of the curvilinear type, 16.67% of cases of the linear type, 22.73% of cases of the sigmiod type and 21.21% of cases of the angular type. And in configurations following course of main duct, those revealed that 83.33% of cases of the smooth type and 16.67% of cases of the tortuous type. 5. The mean caliber of submandibular glands was 45.59㎜ in superoinferior height, 43.56㎜ in anteroposterior width, 28.85㎜ in mediolateral width and 33.65㎜ in extent below mandibular angle. 6. Well-delineated acinar parenchyme was observed in 77.28% of cases and well-defined tertiary ducts in 50.06% of cases. 7. There were no differences between right and left submandibular glands in size and shape of main duct and parenchymal portion, but there were great variations in each individual.

• Journal of Biosystems Engineering
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• v.14 no.4
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• pp.272-281
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• 1989

It is desirable for the vertical wind tunnel which can build uniform air flow across the vertical duct to be used for the purpose of the investigation of the aerodynamic properties of grains. This study was conducted to examine how the air velocity profile in the vertical duct is influenced by the various alternations of the elements of the wind tunnel, and to prepare design guidance of the vertical wind tunnel which can be used for investigating aerodynamic properties of grains. In addition, several tests were conducted to locate the test section which can be applicable for determining the terminal velocity of grain. The following conclusions were obtained from the study: 1. The size and the location of the outlet of the plenum chamber should be determined such that the outlet air flow is less affected by the air flow and the back pressure by the side wall of the chamber. 2. The honeycomb was not helpful for attaining uniform air flow in case that the air flow profile at the bottom of the vertical duct is serverely different from the ideal one. 3. Even though considerable pressure drop was resulted from the screens installed within the vertical duct, the screens were helpful for attaining uniform air flow in the duct. 4. It is desirable for the test section to be located at the position that not only the air flow of the duct is not disturbed by the distorted back pressure in the plenum chamber, but also less boundary layer is developed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.11
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• pp.770-775
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• 2007

Although these days application of heat recovery ventilation and improved kitchen ventilation system came into wide use in mixed-use residential buildings and exclusive residences, there are not enough ventilation systems except the local ventilation of kitchens and rest rooms. It is very important part to regulate and distribute correct air flow rate for controlling air change rate. The purpose of this study is to investigate the application of distributor at house ventilation system by comparing a duct system with out distributor and with distributor. The results of this study are as follows. (1) When using distributor though the size of duct diameter is reduced rapidly, the pressure loss doesn't rise largely. The pressure loss without distributor is 4.08 mmAq, the pressure loss with distributor 4.10 mmAq. (2) To use distributor can reduce materials of duct and secure enough ceiling space by reducing duct diameter. (3) Diameters and air flow paths of distributor on the design stage are important part for accurate air flow rate.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.21-27
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• 2015

The goal of this study is the size and distribution of the electromagnetic force generated by the current flowing through the second underground line of 154kV power transmission cables by using electromagnetic finite element analysis. So we interpret how mutually electromagnetic force has an effect on the comparable judgement of Trefoil, Duct and Flat, which shows in a numerical arrangement. 154kV OF 1200SQ Cable 1.281km not only is applicable to modeling for underground transmission cable but also examine the effect of line to line, phase to phase and size and direction of the electromagnetic force preparing for the occurrence of normal state and single-phase earth fault, which are arranged in trefoil, duct and flat formation between sections. As showing how the trajectory, and size distribution of the electromagnetic force translate as the arrangement of the cables when a steady-state current and a fault current flows on the underground cables, I hope that when Underground transmission is designed, this data will be useful information.

• Journal of Korean Society of Forest Science
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• v.79 no.4
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• pp.424-430
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• 1990

The variation of needle, cone and seed characteristics and of allelic frequency in isoenzyme, ADH, ME and PGI, according to different resin duct index in Pinus densiflora, Pinus thunbergii and their hybrids was analyzed. The results obtained were as follows : 1. With increase of number of resin ducts, morphological characteristics such as needle length, needle sheath length, cone size, seed size, seed wing size, 1000 seeds weight, etc. tended to he increased, while number of stomata row in needle to be decreased. 2. As the results of discriminant analysis for the morphological characteristics of needle, cone and seed, most individuals are generally coincided with number of resin duct mostly in Pinus densiflora were not. 3. According to the canonical discriminant function obtained from the morphological characteristics in Pinus densiflora, Pinus thunbergii and their hybrids including introgressive hybrid, the resin duct index, 1000 seeds weight, cone size and neelde sheath length characterized fairly their species. 4. With increase of resin duct index, hybrid index tended to be higher. The results obtained from the discriminant analysis and the hybrid index were nearly same each other. 5. With increase of number of resin duct, the allelic frequencies for isoenzyme, ADH-$B_2$, ME-$A_2$ and PGI-$B_1$. $B_2$ tended to increase but those of ADH-$B_3$, ME-$A_4$, and PGI-$B_3$, to decrease. It is thought that this increase of frequency for the former four isoenzymes was resulted in introgressive gene flow from Pinus thunbergii to Pines densiflora and accordingly the frequency of latter three isoenzymes tended to decrease.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.265-269
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• 2006

Anti-Roll Tanks, also called Sloshing Tanks, is a rather common and sometimes an efficient method of limiting the roll angles. The important parameters, when considering using anti-roll tanks, are positioning, size, duct area, flow control device etc. Measurement by the PIV(Particle Image Velocimetry) was conducted to investigate the flow characteristics around control damper and inlet area of duct for three kind of inclined angle $(\alpha=0^*,\;10^*\;and\;20^*)$. Flow behaviors such as instantaneous and time-mean velocity vectors are investigated. Furthermore, to reveal boundaries between flowing and stagnant zones and to extract velocity profiles at any selected sections of the lower duct for passive anti-rolling tanks system.

• Fire Science and Engineering
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• v.30 no.2
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• pp.68-74
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• 2016

In semi-transverse ventilation system applied for road tunnel, adjustment of the port opening ratio is an essential part for uniform airflow rate per unit length over the entire tunnel. However, it has not been considered decently throughout the design process and operating of the tunnel. Therefore, in this study, we developed a program for the calculation of the opening size ratio of supply or exhaust port in transverse ventilation system and carried out the research to present a management plan for the port. In supply duct system, the opening size of the port had a tendency to increase and then decrease later when it gradually becomes closer toward the bulkhead at the beginning of the duct the minimum opening degree is to appeared as 56%. In the exhaust system, port size is the smallest at the beginning of duct as 15%, has shown a tendency to increase towards the bulk head. As results of estimating the air flow rate for 300 m intervals, the exhaust flow rate in the center of tunnel appeared to be extremely low as 8.1% and 12.5% when port size is constant and is adjusted supply type. Thus, even if the normal ventilation efficiency is declines, yet it is highly recommend adjusting the port size in order to obtain a uniform flow rate at fire accidents.

• The Journal of the Korean dental association
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• v.5 no.1
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• pp.60-62
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• 1964

The Author have had a case of Salivary-stone in the posterior of Warton's duct in the right Side . 1. The patient was 24 years-old R.O.K.a Soldexr. 2. The salivary stone was 1.6cm by 2.11 cm in big size. 3. There was a History of pain at meal-time, and swelling of mandible of Right region.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.737-742
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• 2007

The method of the reducing duct noise can be classified by passive and active control techniques. However, passive control has a limited effect of noise reduction at low frequencies (below 500Hz) and is limited by the space. On the other hand, active control can overcome these passive control limitations. The active control technique mostly uses the Least-Mean-Square (LMS) algorithm, because the LMS algorithm can easily obtain the complex transfer function in real-time particularly when the Filtered-X LMS (FXLMS) algorithm is applied to an active noise control (ANC) system. However, the convergence performance of the LMS algorithm decreases slightly so it may delay the convergence time when the FXLMS algorithm is applied to the active control of duct noise. Thus the Co-FXLMS algorithm was developed to improve the control performance in order to solve this problem. The Co-FXLMS algorithm is realized by using an estimate of the cross correlation between the adaptation error and the filtered input signal to control the step size. In this paper, the performance of the Co-FXLMS algorithm is presented in comparison with the FXLMS algorithm. Simulation results show that active noise control using Co-FXLMS is effective in reducing duct noise.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.405-409
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• 2001

An experimental analysis of the flow inside the refrigeration compartment of a home refrigerator was conducted in order to achieve better performances in terms of uniform temperature distribution and cooling speed. 2D PIV and stereoscopic PIV were used for the experiments on an actual-size refrigerator at operating conditions. Two CCD cameras were employed for a wider field of view in the measurement of the shelf, and stereoscopic PIV was used to measure the three velocity components at the various cooling duct outlets and the mean velocity fields were area-integrated to calculate the flow-rates. 50 to 100 instantaneous velocity fields were time averaged for the mean velocity fields. With the result of this analysis, a new cooling duct system was developed, with the refrigerator's cooling performance increasing 11% in terms of cooling speed, and 25% in temperature uniformity.