• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.177-187
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• 1996

This paper is concerned with the comparison and chronological changes of the physical constitution of the Korean youth, age range 6-17. For the purpose, anthropometric data of schoolchildrens are surveyed from the Statistlcal Yearbook of Education published in Ministry of Education. The results show that body dimensions have increased consistently from 1964 to 1994. During the last 30years, stature has increased by about 1cm to 6cm per decade, on the average, and body weight has increased by about 1kg to 5kg per decade. On the other hand, silting height and chest circumference have increased by about 0.5cm to 3cm per decade. The results also show that there are significant sex differences in the characteristics of physical growth. These findings identified in this study mean that boys and girls have essentially different requirements for the design of the workplace.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.320-326
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• 2019

The diet composition of Arctoscopus japonicus was studied using 448 specimens collected in the coastal waters of East Sea, Korea. The size of the specimens ranged from 6.2-25.3 cm in total length (TL). A. japonicus were fed mainly on amphipods that constituted 76.1% in IRI. Euphausiids were the second largest prey component. The diets also include small quantities of crabs, copepods, mysids, cephalopods, monogeneans, and fishes. A. japonicus showed ontogenetic changes in feeding habits. Smaller individuals (6-10 cm, TL) fed mainly on amphipods. The proportion of amphipods decreased as body size increased, whereas the consumption of euphausiids gradually increased (10-14 cm, TL). As the body size more increased, the proportion of amphipods increased whereas euphausiids decreased (14-26 cm, TL).

• Journal of The Korean Association For Science Education
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• v.9 no.2
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• pp.47-53
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• 1989

The standard of chair and desk is decided to design a science laboratory which would help students giving the chance to show their ability and participating spontaneously. The standard is come by the middle school students physical size of the 1986 national physical standard and they are classified into large, medium and small size. The size of laboratory is determined by the size of desk. the distance between desks and the number of students accommodated. By the middle school students physical standard, the heights of chair are 32, 34, 37cm and the widths of chair are 35, 37, 40cm. The desks heights are 53, 58, 63cm and the size is $110{\times}160cm$. The distance between rear and front of desk is 120cm and the left and right side of desk is 150cm. When 24, 36, 60 students are accommodated in laboratory, the size of laboratories are $9.6{\times}10.5m$, $12.7{\times}10.5m$ and $18.8{\times}10.5m$ respectively.

• Korean Journal of Exercise Nutrition
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• v.24 no.4
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• pp.7-14
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• 2020

[Purpose] This study evaluated the anti-atopic dermatitis (AD) properties of Cordyceps militaris (CM) aqueous extract in keratinocytes in vitro and in vivo. We investigated the nutraceutical composition of the CM extract, including its protein, carbohydrate, and selected phytochemical content. [Methods] The expression of pathogenic cytokines in keratinocytes was assayed using an in vitro model. The CM extract downregulated extracellular signalregulated kinase 1/2 (ERK1/2) and p38 kinase expression in TNFα/IFNγ-stimulated HaCaT cells. We also established an in vivo AD model by repeatedly exposing the ears of mice to local Dermatophagoides farinae extract (DFE; house dust mite extract) and 2,4-dinitrochlorobenzene (DNCB). The epidermal and dermal ear thickness, mast cell infiltration, and serum immunoglobulin levels were measured following a 4-week oral administration of the CM extract. [Results] Histopathological examination showed reduced epidermal/dermal thickness and mast cell infiltration in mouse ears. The CM extract also suppressed serum immunoglobulin levels and gene expression of T helper (Th)1/Th2 cytokines in mouse ear tissue. [Conclusion] These results suggest that the CM extract may be useful for the treatment of AD-like skin lesions.

• Korean Journal of Ichthyology
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• v.35 no.3
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• pp.177-182
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• 2023

Total 158 Conger myriaster were examined and the range of Preanal length (PaL) was 8.2~40.1 cm and average Preanal length was 17.3 cm. Proportion of the empty stomach was 30.4% and individuals, which the prey items were found in stomach, were 110. The most important prey component in the diets of C. myriaster was Pisces that constituted 54.4% in %IRI (Index of relative importance). Engraulis japonicus was the most important prey component in Pisces. Macrura was the second largest prey component and Crangon hakodatei was the most important prey component in Macrura. The result of analysis in ontogenetic changes significantly exhibited among three size classes (<15.0 cm, 15.0~20.0 cm, ≥20.0 cm). The proportion of Macrura decreased as increasing body size, whereas the consumption of Pisces increased gradually. As body size of C. myriaster increased, the mean weight of prey per stomach (mW/ST) increased (one way-ANOVA, P<0.05).

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.21-30
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• 2006

The purpose of the study is to search for the possibility of the application of kinematics analysis to physical education at schools and expand its scope of application. This study chose 9 college students majoring in physical education and classified them into type A group who can make the straight, vertical handstand, type B group whose waist is bent, type C group who cannot handstand completely. The center of mass, distance between hand and leg, and the angle and angular velocity of each joint were obtained. The result of this study is this. 1. The time for CM showed 6:4 for A group and 5:5 for B and C groups. The distance between hand and foot in the event 3 was 44% of the height for A group, and 41% for B and C groups. A Group showed the higher CM positional significant difference, it was vertically direction below the hip joint at front. For significant difference of the B Group showed horizontal and vertical velocity of the CM, the highest vertical was obtained in phase 3. The difference of angle of shoulder join in the flexion/extension was showed gradually extension event 2 and the height angular velocity was at phase 3 in the A group. 2 The analysis of the handstand motion revealed that the phase 3, but the maintenance of posture start part the handstand is also very important. Through these results, this study confirmed that the time for phase of the CM, horizontal and vertical positions, velocity, the distance between hands and foot, and the difference of the angle and angular velocity of hip joint and shoulder joint can be set as the variables of analysis. It was also definite cause that the handstand motions of college students majoring in physical education had many difference in performance.

• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.379-386
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• 2012

The aim of this study was to investigate and identify the differences in lower extremity energy dissipation strategies between drop-landing and countermovement-jump maneuvers. Fourteen recreational athletes(Age : $23.3{\pm}2.1years$, Height : $172.3{\pm}4.0cm$, Weight : $69.2{\pm}4.7kg$) were recruited and instructed to perform drop-landing from 45 cm height and countermovement-jump from 45 cm to 20 cm height. The landing phase was taken as the time between initial contact and peak knee flexion. A motion-capture system consisting of eight infra-red cameras was employed to collect kinematics data at a sampling rate of 200 Hz and a force-plate was used to collect GRF data at a sampling rate of 2000 Hz. Paired t-test was performed to determine the difference in kinematics and kinetics variables between each task. During the countermovement-jump task, all of lower extremity joint ROM and the hip joint eccentric moment were decreased and the ankle joint plantarflexion moment was increased than drop-landing task. In the eccentric work during countermovement-jump task, the ankle joint displayed greater while knee and hip joint showed lesser than drop-landing. Therefore, the knee joint acted as the key energy dissipater during drop-landing while the ankle joint contributed the most energy dissipation during countermovement-jump. Our findings collectively indicated that different energy dissipation strategies were adopted for drop-landing and countermovement-jump.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.335-343
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• 2011

Patellofemoral pain syndrome is the most common problem involving the knee, accounting for 25% of knee injuries. Repetitive, overuse activities cause increased force at the patellofemoral joint, resulting in pain during flexion and extension activities. Most research have been conducted in exploring the patellofemoral compressive force in gait, squat and lunges, even though in real cases, possibilities in landing exist. The purpose of this study was to compare the differences in patellofemoral compressive force according to two different height. Sixteen collegiate male students(age: 22.25 ${\pm}$ 3.30 yrs, height: 177.25 ${\pm}$ 4.44 cm, weight: 77.50 ${\pm}$ 8.18 kg) were chosen. The subjects performed drop landings in 45 cm, 60 cm. The findings demonstrated that higher height showed peak knee extension moment, quadriceps contraction force, patellofemoral compressive force with increased VGRF. Regarding the patellofemoral joint compressive force, it increased by quadriceps contraction force with knee flexion during landing, yet, it showed no difference in maximal knee flexion. To minimize patellofemoral joint stress and reduce the likelihood of developing PFPS, we recommend that predesigned quadriceps and hip muscle group strengthening are needed during conditioning and training.

• Journal of the Korean Chemical Society
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• v.67 no.6
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• pp.407-414
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• 2023

The present study uses quasi-classical trajectory procedures to examine the vibrational relaxation and dissociation of the methyl and ring C-H bonds in excited methylpyrazine (MP) during collision with either N₂ or O₂. The energy-loss (-ΔE) of the excited MP is calculated as the total vibrational energy (E_T) of MP is increased in the range of 5,000 to 40,000cm^-1. The results indicate that the collision-induced vibrational relaxation of MP is not large, increasing gradually with increasing E_T between 5,000 and 30,000 cm^-1, but then decreasing with the further increase in E_T. In both N₂ and O₂ collisions, the vibrational relaxation of MP occurs mainly via the vibration-to-translation (V→T) and vibration-to-vibration (V→V) energy transfer pathways, while the vibration-to-rotation (V→R) energy transfer pathway is negligible. In both collision systems, the V→T transfer shows a similar pattern and amount of energy loss in the ET range of 5,000 to 40,000cm^-1, whereas the pattern and amount of energy transfer via the V→V pathway differs significantly between two collision systems. The collision-induced dissociation of the C-H_methyl or C-H_ring bond occurs when highly excited MP (65,000-72,000 cm^-1) interacts with the ground-state N₂ or O₂. Here, the dissociation probability is low (10^-4-10^-1), but increases exponentially with increasing vibrational excitation. This can be interpreted as the intermolecular interaction below E_T = 71,000 cm^-1. By contrast, the bond dissociation above E_T = 71,000 cm^-1 is due to the intramolecular energy flow between the excited C-H bonds. The probability of C-H_methyl dissociation is higher than that of C-H_ring dissociation.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.223-226
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• 2009

A Magneto-Optical Trap (MOT) for $^{87}Rb$ atoms near the surface of a dielectric coated mirror at the top of a small $20{\times}25{\times}40\;mm^3$ cell has been observed. Two beams of $3.3\;mW/cm^2$ were used for optical cooling and an anti-Helmholtz magnetic field with a spatial gradient of 9.1 G/cm was used for magnetic trapping. The thickness of the mirror coated on a cover glass was less than $100{\mu}m$. The mirror covered the top of a cell and the atom-chip was located outside the vacuum in order to exploit the long life time of the mirror and easy operation of the chip. The trapping position was found 5 mm beneath the mirror surface. The number of trapped atoms was roughly $3{\times}10^7$ atoms and the temperature was approximately a few tens mK. In this paper, we describe the construction of the mirror-MOT in detail.