• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.1
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• pp.225-233
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• 1998

The purpose of this study was to determine the thickness of the cortical bone at the mandibular angle in children and adolescents. The subjects were composed of 153 subjects who were 3 to 17 years of age that had not been history of bone disease or metabolic disease and no dental caries or tooth loss on mandibular molars. The subjects were divided into three age groups, group I (preschool children) was 3 to 5 years of age and grouop II (school children) was 6 to 11 years of age and group III (adolescence) was 12 to 17 years of age. Panoramic radiographs of these patients were collected and measurements of the thickness of the cortical bone were obtained at the mandibular angle. The average thickness of the cortical bone in the group I was 1.01$\pm$0.18 mm in boys and 1.07$\pm$0.22 mm in girls. In the group II was 1.23$\pm$0.18 mm in boys and 1.32$\pm$0.18 mm in girls. In the group III was 1.60$\pm$0.23 mm in boys and 1.58$\pm$0.20 mm in girls. Statistical analyses did not reveal any significant difference between the right or left side of the mandible but difference was exist between the same age groups by sex, especially in group II (p<0.01), except in group III. The greater thickness of cortical bone in the older age group was shown to be statistically significant. The correlation coefficient between age and the thickness of the cortical bone at the mandibular angle showed a high value of r=0.76.

• Journal of Radiation Protection and Research
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• v.29 no.3
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• pp.179-186
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• 2004

A single-dosimeter worn on the anterior surface of body of a worker was found to provide significant underestimation of dose to the worker when radiation comes from behind of the human body. Recently, several researchers suggested that this kind of underestimation can be corrected to a certain extent by using an extra dosimeter on the back. But this multiple dosimetry also has the disadvantages like overestimation lowering work efficiency or cost burden. In this study, a single dosimeter introducing asymmetric filters enabled to identify PA exposure was designed by monte-carlo simulation and experiments and its dose evaluation algorithm for AP-PA mixed radiation field was established. This algorithm was applicable to penetrating radiation which had the effective energy more than 100 keV. Besides, the dosimeter and algorithm in this study were possible to be applied to near PA exposure.

• Journal of the Mineralogical Society of Korea
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• v.28 no.4
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• pp.325-332
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• 2015

Apophyllite (KF)($K_{0.84}Ca_{3.99}Si_{7.70}O_{20}F_{0.72}{\cdot}8H_2O$), one of the sheet silicates, was compressed up to 7.7 GPa at ambient temperature and 15 high pressure data were obtained. Lattice parameters of the starting specimen were as follows: $a_0=8.954(2)\;{\AA}$, $c_0=15.795(2)\;{\AA}$, $V_0=1266.4(4)\;{\AA}^3$. Symmetrical diamond anvil cell was employed with synchrotron radiation in the mode of angular dispersive X-ray diffraction. Bulk modulus was determined to be 59(4) GPa when ${K_0}^{\prime}$ is 4. No clear first order phase transition symptom was observed in the series of XRD pattern. However, second-order phase transition cannot be ruled out from the correlation between normalized pressure and strain.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.12
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• pp.1067-1076
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• 2016

This paper describes the development of a hybrid-powered wheelchair (HPW) for the elderly. The proposed HPW has novel mechanical and control features compared with conventional powered wheelchairs. An ergonomic back-braking mechanism was designed in order to stop the wheels easily. In terms of control features, the HPW remarkably reduces the muscle power required by combining various assistive functions, such as wheel torque assistance, friction/inertia compensation, gravity compensation, and the one-hand driving algorithm. For wheel torque assistance, strain gauges were attached to the hand-rim in order to measure the wheel torque applied by a human. Gyroscopes and an accelerometer were attached to the wheel and chair respectively for friction and inertia compensation. An inclinometer was attached for gravity compensation and the one-hand driving algorithm was included for patients who can only use one hand. The one-hand driving algorithm controls the angular velocity of the uncontrolled wheel by using a gyroscope and pressure sensors attached to the bottom of the seat. Finally, the performance of the proposed motion assisted algorithm was verified through various experiments.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.175-180
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• 2020

In this study, the freight vehicles were modelled and the flow analysis on the existence or non-existence of a cargo container and the wind deflector were carried out. Based on the driving speed of 100 km/hr, at all models A, B and C, the highest flow rate was shown between 58 m/s and 59 m/s at the top of the model shape. All models A, B and C showed the highest pressure of air resistance between 652Pa and 671Pa at the front of the model geometry. The maximum pressure of model A is considered to be the smallest, with the least flow resistance to speed compared to models B and C. Therefore, it can be seen that model A has an advantageous condition for air resistance in terms of fuel costs. Unlike model B which causes the rapid flow resistance at the cargo compartment, model C can be found to flow a little more smoothly on the streamlined wind deflector. So, the flow air at a streamlined shape is considered to be more advantageous in terms of air resistance than at angular shape. By applying the research analysis result on the air flow in driving according to a cargo container and the wind deflector, it is seen that this study is adequate at the practical efficient design and aesthetic convergence.

• Journal of Sensor Science and Technology
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• v.10 no.1
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• pp.1-8
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• 2001

Conventional microgyroscopes of vibrating type require resonant frequency tuning of the driving and sensing modes to achieve high sensitivity. These tuning conditions depend on each fabricated microgyroscopes, even though the microgyroscopes are identically designed. A new micromachined resonator, which is applicable to microgyroscopes with self-toning characteristics, is presented. Since the laterally driven two degrees of freedom (2DOF) resonator was designed as a symmetric structure with identical stiffness in two orthogonal axes, the resonator is applicable to vibrating microgyroscopes, which do not need mode tuning. A dynamic model of the resonator was derived considering gyroscopic application. The dynamic model was evaluated by experimental comparison with fabricated resonators. The microgyroscopes were fabricated using a simple 2-mask-process of a single polysilicon layer deposited on an insulator layer. The feasibility of the resonator as a vibrating microgyroscopes with self-tuning capability is discussed. The fabricated resonators of a particular design have process-induced non-uniformities that cause different resonant frequencies. For several resonators, the standard deviations of the driving and sensing frequencies were as high as 1232Hz and 1214Hz, whereas the experimental average detuning frequency was 91.75Hz. The minimum detuned frequency was 68Hz with $0.034mVsec/^{\circ}$ sensitivity. The sensitivity of the microgyroscopes was low due to process-induced non-uniformity; the angular rate bandwidth, however, was wide. This resonator could be successfully applicable to a vibrating microgyroscopes with high sensitivity, if improvements in uniformity of the fabrication process are achieved. Further developments in improved integrated circuits are expected to lower the noise level even more.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.197-207
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• 2007

It has been reported that Back-Tension played a significant role in archery (Lee & Bondit, 2005; Kim, 2007) but there are a few researches related Back-Tension in Korea recently. Therefore, the purpose of this study was to investigate archery back tension technique for the second ranked archer in the World and to find ways to improve performance. A subject(height: 185cm, mass: 82kg, years: 21yrs, careers: 12yrs) who is a number of national team and the second ranked archer in the World authorized by FITA (Federation Internationale de Trial Arc) was perticipated in this experiment. When shooting 60 shots($12{\times}5$), shooting motions were recorded with 7 infrared cameras and 2 ultrahigh-speed cameras. A QTM and an Auto Track were used to acquire raw data. The sampling rates of both cameras were 200 Hz. and 1000 Hz. respectively and data were filtered using a fourth order Butterworth low pass filtering with a cutoff-frequency of 30Hz. The parameters were calculated with Matlab6.5 and analyzed with SPSS11.0. After Pearson's correlations between 8 parameters were analyzed, 5 parameters from 13parameters that affected records were analyzed with multiple regression analysis (Enter order: x1, x2, x3, x4, x5). The results were as follows: 1. Comparing between parameters according to scores, the patterns of horizontal and vertical angular velocity(av.) of scapular relative angle was different between 8 score and 9 or 10 scores. 2. The correlations of parameters that affected records were a horizontal av.(x1, p=.032<.05) and a vertical av.(x3, p=.033<.05) of scapular from release to delivery in KB back-tension (anchoring-delivery). 3. The decision coefficients(R2) of above two parameters and three parameters selected by experts that may affect record, that is, an absolute trunk angle(x4) from in KKC back-tension (anchoring-release) and a horizontal relative scapular angle(x2) and an absolute trunk angle(x5) from release to delivery in KB back-tension were 7.7%(x1), 0.1%(x2), 8.5%(x3), 0.7%(x4) and 0.9%(x5) in sequence. 4. The multiple regression equation was a y= -1.16E-2 x1 + 0.109 x2 + 3.437E-2 x3 + 6.139E-2 x4 + 0.117 x5 + 3.420 In conclusion, a total contribution was low, that is, R2(17.9%) suggested that on the one hand, Lim's motion may not depend on a certain factor because his postural factors affected shooting motion are some stable on the other hand, unknown factors may exist(e.g. psychological, physiological factors etc.). Further study of EMG patterns of muscles and anatomic consideration related to shoulder girdle and scapular bones may help to identify mechanism of Back-Tension.

• Research in Plant Disease
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• v.9 no.1
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• pp.32-35
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• 2003

Pink rot of potato (Solanum tuberosum L.) occurred at Pyeongchang in Gangwon and at Bosung in Junnam province since 1999. The disease incidence in the surveyed areas was about 5% of harvested potatoes in 2002. Affected tubers showed a dull brown appearance and the lenticels and eyes on tubers turned dark brown. The cut surface of the diseased tuber colored faint pink and the entire surface of the diseased tuber becomes deep salmon pink within 30 min. The pathogen isolated from the diseased tubers was identified as Phytophthora erythroseptica based on morphological and cultural characteristics. Mycelial mat was fairly fluffy, rosette or stellate patterns and rounded or angular hyphal swellings were farmed in water, Temperature for mycelial growth was ranged from 5 to 3$0^{\circ}C$ and optimal temperature was $25^{\circ}C$. Non-papillate sporangia were persistent on stalk and ellipsoid, ovoid, obpyriform or distorted in shape, often with a constriction distal in the middle. Size of sporangia was 41.3~69.6$\times$26.8~47.4 (av, 55.5$\times$37.1) ${\mu}{\textrm}{m}$. Sexuality of Phytophthora erythroseptica was homothallic. Oogonia were 30~46 ${\mu}{\textrm}{m}$ in diameter and oospores were 28~35 ${\mu}{\textrm}{m}$ in diameter, Elongated or cyclindrical antheridia were all amphigynous. This is the first report on potato pink rot caused by Phytophthora erythroseptica in Korea.

• Korean Journal of Poultry Science
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• v.20 no.3
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• pp.115-123
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• 1993

Mechanically deboned chicken meat(MDCM ) from necks and backs was blended with 0.1% oleoresin rosemary, 0.1% oleoresin sage and 0.05% rosemary combined with 0.05% sage to evaluate retardation of oxidative rancidity during storage at$3^{\circ}C$ and $-25^{\circ}C$, respectively. 1. Moisture content of MDCM was 66.3%. protein 17.6%, fat 15.0% and ash 1.10%. Several types of bone particles such as angular and needle like shape in MDCM were observed by light microscope. 2. Lipid oxidation of MDCM started to increase after 2 day and increase rapidly after 6 day of storage at $3^{\circ}C$. Oleoresin sage and rosemary apparently retarded oxidative rancidity of MDCM during refrigerated and frozen storage, TBA and total carbonyl values demonstrated that sage was more effective antioxidant than rosemary, and sage /rosemary combination was the most effective antioxidant among them. 3. The oxidative rancidity of MDCM apparently accelerated after 50 days of storage at $-25^{\circ}C$. The addition of oleoresin sage and rosemary inhibited oxidizing changes stored for 100 days at -$25^{\circ}C$.

• Journal of Veterinary Clinics
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• v.32 no.6
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• pp.481-485
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• 2015

The present study determined the normal reference ranges for overall pelvic limb alignment of small-breed dogs. For this purpose, 60 cadaveric canine pelvic limbs from normal small-breed dogs (Maltese, Poodle, Shih Tzu, Yorkshire Terrier). A frontal full-limb radiograph of each pelvic limb was obtained, and mechanical tibiofemoral angle (mTFA), mechanical metatarsotibial angle (mMTTA), mechanical axis-femur angle (MAFA), and mechanical axis-metatarsus angle (MAMTA) were measured from each radiograph, along with mechanical deviation of the stifle (SMAD) and tarsal joints (TMAD). The 95% CI for radiographic values of all pelvic limbs were mTFA, 5.7-7.4; mMTTA, $-2.2--0.8^{\circ}$; MAFA, $3.5-4.5^{\circ}$; MAMTA, 1.0-2.0; SMAD, 2.1-2.7%; TMAD, 0.5-1.0%. There values varied among the breeds, except for mTFA. The reference ranges can be used for diagnosing pelvic limb deformities in small-breed dogs and for planning corrective osteotomies.