• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.8
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• pp.585-592
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• 2007

Good cold start characteristics are essential for satisfactory operation of fuel cell vehicles. In this study, the melting process has been numerically investigated for a water tank used in fuel cell vehicles. The 2-D model of the tank containing ice and plate heaters was assumed and the unsteady melting process of the ice was calculated. The enthalpy method was used for the description of the melting process, and a FVM code was used to solve the problem. The feasibility study compared with other experiment showed that the developed program was able to describe the melting process well. From the numerical analysis carried out for different wall temperatures of the pate heaters, some important design factors could be found such as local overheating and pressurization in the tank.

• Journal of the Korean Ceramic Society
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• v.43 no.2 s.285
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• pp.69-73
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• 2006

A full retention of the tetragonal phase with coarse grains $(50\~60\;{\mu}m)$ was possible with the specimen $ZrO_2-1.9\;mol\%\;Y_2O_3$. In these coarse grains, $\{101\}_t$ annealing twins were frequently observed, although they do not exist in the usual fine grained specimens. The morphology and growth rate of the isothermally formed individual products are studied at an optical microscopic level. The habit planes of both products are also identified by performing two-surface trace analysis on the grains whose orientations are determined by the Electron Back Scattering Pattern (EBSP) method. The morphologies of isothermal martensite were well-defined thin plates and lenticular types. The growth rate in their longitudinal directions was quite slow and temperature-dependent. A two-surface trace analysis, incorporated with the EBSP method, identified the habit planes near $\{013\}_c$, in agreement with previous reports obtained from TEM works.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.116-122
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• 2010

It is necessary to be careful about contamination control to minimize the accumulation of the contamination material on satellite surface during the I&T phase. In the space environment which characterized by high vacuum, high and very low temperature, contamination material causes satellite to lose its own performance. Especially, contamination material can accumulate on critical surfaces such as lenses, mirrors, and sensors. KARI(Korea Aerospace Research Institute) conducts the clean room to control and minimize the contamination effect. This paper introduces the principle of contamination and the method of measure and analysis for the contamination.

• Physical Therapy Korea
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• v.19 no.3
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• pp.81-90
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• 2012

The aim of the current study was to assess the effectiveness of backward gait training on the treadmill in patients with spastic diplegic cerebral palsy (CP). Twelve patients with spastic diplegic CP participated in the study. An 8-week course of backward gait training was administered to the subjects for 3 days per week. Pre-intervention and post-intervention assessments of temporal-spatial gait parameters, the symmetry of the bilateral lower extremity weight bearing, and gross motor function were analyzed using motion analysis system, force plate, and Gross Motor Function Measurement (GMFM). There were significant improvements (p<.05) in the measures of both step length and right stance phase time. Joint kinematics showed increase in right hip abduction in initial contact and terminal swing, right hip external rotation and knee flexion in mid-swing, left ankle dorsiflexion in initial contact and terminal swing (p<.05). The symmetry of the bilateral lower extremity weight bearing and GMFM also significantly increased (p<.05). These findings indicate that backward gait training using a treadmill is beneficial for patients with spastic diplegic CP.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2101-2112
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• 1994

A two-dimensional biomechanical model was developed in order to calculated the lower extremity kinematics and kinetics during level walking. This model consists of three segments : the thigh, calf, and foot. Each segment was assumed to be a rigid body ; its motion to be planar in the sagittal plane. Five young males were involved in the gait experiment and their anthropometric data were measured for the calculation of segmental masses and moments of inertial. Six markers were used to obtain the kinematic data of the right lower extremity for at least three trials of walking at 1.0m/s, and simultaneously a Kistler force plate was used to obtain the foot-floor reaction data. Based on the experimental data acquired for the stance phase of the right foot, calculated vertical joint forces reached up to 0.91, 1.05, and 1.11 BW(body weight) at the hip, the knee, the ankle joints, respectively. The flexion-extension moments reached up to 69.7, 52.3, and 98.8 Nm in magnitude at the corresponding three joints. It was found that the calculated joint loadings of a subject were statistically the same for all his three trials, but not the same for all five subjects involved in the gait study.

• Journal of Food Hygiene and Safety
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• v.11 no.3
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• pp.177-187
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• 1996

Time-temperature relationship and microbiological quality were assessed and critical control points were identified through hazard analysis during the phases of production in two different packaged meals (Dosirak) manufacturing establishments (A, B:Kim Pab). Microbiological tests on foods, equipments and utensils were done according to standard procedures and included total plate count, coliforms and fecal coliforms. The results of the study are summarized as follows : time-temperature control management was needed because time-temperature abuse more than 8 hours at dangerous temperature zone (5-6$0^{\circ}C$) was observed from pre-preperation to distribution phase; Poor sanitary practices of employees were observed in hand washing and using disposable gloves; Microbiological analysis results of equirpments and utensils showed possible cross-contamination risks when foods were contacted with them; Kim Pab needed thorough quality control because it included various mixed ingredients of cooked and uncooked and had many apportunities of cross-contamination either by equipments or hands through whole production processes.

• The Plant Pathology Journal
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• v.16 no.4
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• pp.189-199
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• 2000

To search for the antifungal substances, various actino-mycete isolates were obtained from various soils of Korea using plate dilution method on the humic acid vitamin agar plates. In the screening procedures using a dual culture method, 32 actionomycete isolates were selected, which showed the inhibitory activity against mycelial growth of plant pathogenic fungi Altirnaria mali, Colletotrichum gloeosporides, Fusarium oxysporum f.sp. cucumerinum, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. Bioassay of the crude extracts from culture filtrates and mycelial mets revealed that 12 antagonistic actionomycetes produced highly active antifungal substances. Actinomycete strain S5-55 which showed the substantial antifungal activity against the tested fungi was selected for production of the antifungal substances. Based on the cytochemical and morphological characteristics, strain S5-55 was identified as a Streptomyces species. The results of the numerical identification using the TAXON program confirmed that Streptomyces strain S5-55 was identical with Streptomyces humidus including in TAXON major cluster 19. The production of antifungal substance was most favorable when S. humidus strain S5-55 was cultivated for 10 dats on soluble starch broth supplemented with $K_2$HPO$_4$. The antifungal substances active against the plant pathogenic fungi P. capsici and M. grisea were partially purified using $\textrm{C}_{18}$ reversed-phase column chromatography.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.259-274
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• 2005

The purpose of this study was to compare the kinematic and kinetic parameters of lower extremity joints between novice and experienced sports aerobic dancers during two heights of depth jumps. Four male dancers were participated in this study and they performed 40cm and 60cm height depth jump three times, respectively. Four ProReflex MCU cameras (100frame/sec) and a Kistler force plate (1000Hz) were used for data collection. The results indicated that the duration of contact phase of experienced group was shorter than that of novice group regardless of jump height. For minimum angle of hip, knee, and ankle joints, the novice group had tendency to decrease the angle but the experienced group had increased the joint angle with jump height. There was no difference of total ground reaction force between the groups but the reaction force had tendency to increase with jump height. Thus, this study implied that repetition of jump and landing may induce joint related injury and further study such as. EMG analysis of lower extremity can be needed to verify the relationship between injury and ground reaction force.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.91-109
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• 2005

The goal of this research was to determine whether gender differences exist in impact force and impact shock variables at stance phase during a preferred running. Ten male and ten female subjects volunteered to participate in this study. Impact force was quantified by using a surface-mounted force plate. In addition, Axial accelerations of the tibias and mouth were measured using low-mass accelerometers. Comparison of parameters relating to impact force and impact shock which attained from time domain, and impact shock parameters which were analyzed in frequency domain were made between genders. The conclusions based on results were as follows; 1. There were no significantly differences in impact force, mouth and tibia acceleration peak in time domain between two genders. 2. The male group was greater in impact shock peak of PSD(power spectral density) at the tibia than female group(p<.05), but no differences in active impact of PSD at the tibia and the mouth between two genders. 3. Female subjects exhibited that a peak of impact shock attenuation analyzed in frequency domain moved toward a high frequency, but no difference in time domain between two genders.

• Biomolecules & Therapeutics
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• v.21 no.5
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• pp.391-397
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• 2013

In the present study, we aimed to analyze the antinociceptive, immunomodulatory and antipyretic activities of nymphayol were investigated in wistar rats and mice. Antinociceptive effect was evaluated by acetic acid induced writhing, formalin induced paw licking and hot-plate tests. Immunomodulatory activity was assessed by neutrophil adhesion test, humoral response to sheep red blood cells, delayed-type hypersensitivity, phagocytic activity and cyclophosphamide induced myelosuppression. Antipyretic activity was evaluated by yeast induced hyperthermia in rats. Nymphayol produced significant (p<0.05) antinociceptive activity in acetic acid induced writhing response and late phase of the formalin induced paw licking response. Pre-treatment with nymphayol (50 mg/kg, oral) evoked a significant increase in neutrophil adhesion to nylon fibres. The augmentation of humoral immune response to sheep red blood cells by nymphayol (50 mg/kg) was evidenced by increase in antibody titres in rats. Oral administration of nymphayol (50 mg/kg) to rats potentiated the delayed-type hypersensitivity reaction induced by sheep red blood cells. Treatment with nymphayol showed a significant (p<0.05) reduction in pyrexia in rats. The results suggest that nymphayol possesses potent anti-nociceptive, immunomodulatory and antipyretic activities.