• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.154-159
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• 2004

A new microflow rate controller for medical injection was developed and evaluated. The flow rate was controlled by changing the friction depth as well as the friction length of the micro-channel. A precise micro-fabrication of the micro-channel was requested for an accurate flow control. The friction depth was inversely proportional to the friction length, which gives a linear flow control to the channel length. The channel groove was fabricated with a plastic material. A rubber containing silicone oil was covered over the groove, which satisfies both lubrication and leakage prevention. The flow controller was validated by performing the numerical simulation and experiment. A good agreement was shown between computation and experiment.

• The Korean Journal of Zoology
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• v.5 no.1
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• pp.35-38
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• 1962

Two subspecies are known to Family Hylidae(Order Anura) in Korea : namely , Hylaarborea japonica GUENTHER and H.a.stepheni BOULENGER, and they have been hitherto distinguished as different subspecies from four characteristics : the rate of interorbital to incternasal length, the rate of diameter of tympanum to diameter of 3 rd finger disc, the rate of the length of inner metatarsal tubercle to diameter of 3 rd finger disc, and the rate of inner metatarsal tubercle to the length of lst toe. The author has compared the above to subspecies for the characteristics with 123 individuals collected from ten different localities in Korea and has found that their fluctation curves overlap each other. The author considers, therefore, that the four characteristics could not be assumed as keys for the classification of the two subspecies and has reached the conclusion that these two subspecies should be regarded as one subspecies and Hyla arborea japonica GUENTHER should be given to both of them as the subspecies name.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.5
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• pp.264-267
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• 2004

Recently the pulsed power systems have been widely used in many fields such as E/P(Electrostatic Precipitator), DeNOx/DeSOx power systems, ozone generators and power sources of the laser beam. In this paper, we studied various electrical characteristics for arc suppression of line-to-line electrodes in air and removal of the metaloxide using our pulsed power system. To obtain high efficiency of the pulsed power system, we repeatedly experimented and tested their characteristics. by adjusting electrode length of the load. As a result, when the value of the electrode length and pulse repetition rate were changed at the load, the value of the arc voltage changed at the electrode load. In conclusion, we controlled arc voltage of the load by ,changing electrode length and pulse repetition rate. Also. we stydied removal area of the metaloxide using area discharge according to pulse repetition rate.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.13-18
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• 2013

This study was conducted to examine the effect of temperature and relative humidity (RH) that might affect the pollen germination rate and pollen tube length in oriental melon. The experiment was performed using three cultivars namely 'Mallijangseong', 'Ohbokggul', and 'Joeundae' wherein environmental conditions were controlled by three different temperatures $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$ and also three RH levels 30%, 60%, and 90%. Based on the results in terms of temperature, true to all cultivars, plants exposed to $25^{\circ}C$ had the highest pollen germination rate while plants exposed to $15^{\circ}C$ had the lowest. Among the three cultivars, 'Mallijangseong' had the highest in terms of pollen germination rate, followed by 'Ohbokggul', and lastly was 'Joeundae' that showed the lowest germination rate. In the case of pollen tube length, pollen exposed under $35^{\circ}C$ showed the longest tube length, followed by pollen under $25^{\circ}C$, and pollen under $15^{\circ}C$ remarkably had the shortest tube length. Across the three cultivars 'Ohbokggul' had the longest pollen tube length. In the case of RH, pollen germination response among three cultivars depends on the humidity conditions but based on the results, there was no significant differences although high germination rate was observed in highest humidity condition. Between each cultivar, 'Ohbokggul' had the lowest pollen germination rate compared with 'Mallijangseong' and 'Joeundae' after exposure to different RH conditions wherein pollen germination showed significant differences among treatments. The pollen collected under 60% RH had the longest pollen tube length, followed by 30%, and the shortest was under 90% RH. In general, 'Ohbokggul' had the longest pollen tube length while 'Joeundae' had the shortest among the three cultivars.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.4
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• pp.281-286
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• 2000

To analyze the shape of the net mouth of bottom trawl which is composed with 6 seams net, the field experiment was carried out on the sea near Kokunsan Is, Western sea of Korea. The distance of otter board, net height, trawl speed and resistance of the fishing gear were respectively measured according to the change of warp length and towing speed. The results obtained are summarized as follows : 1. The spreading distance of the otter board has been increased straightly according to the increment of towing speed and warp length. The rate of increase by the warp length has been greatly higher than the rate of increase by the towing speed. The total variation of the spreading distance was 57.0-82.8m, and it was occupied 43-62% of the hand rope, net pendent and the length of nets. 2. The height of net mouth has been decreased straightly according to the increment of towing speed and warp length. The rate of decrease by the towing speed has been greatly higher than the decrease rate of the warp length. The total variation of the net height was 3.1-4.0m. 3. When the distance of wing tip is increased, the height of net mouth is decreased, but the ratio of the decreasing rate of the height of net mouth for the increasing rate of the distance of wing tip was gradually low according to the increment of warp length. 4. The ratio of the distance of both wing tip for the height of net mouth has been increased gradually according to the increment of towing speed and warp length, and the total variation of the ratio was 4.17-7.81 times.

• Korean Journal of Poultry Science
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• v.49 no.1
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• pp.15-23
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• 2022

We compared the degrees of vitality of 12 Korean native chicken breeds, such as Jaeraejong, Korean Rhode Island Red (Rhode), Korean White Leghorn, Korean Cornish (Cornish), and Korean Ogye breeds. The survival rate and telomere length were measured as vital markers. Telomere length was analyzed via quantitative fluorescence in situ hybridization method using the lymphocytes of 466 chickens. We found that the telomere length decreased linearly with increasing chronological age in all chicken breeds. Telomere length and telomere shortening rates (TSR) were significantly different among the chicken breeds after 20 weeks of age (P<0.01). Rhode had the longest telomere length and the lowest TSR, whereas Cornish had the shortest telomere length and the highest TSR. In terms of TSR, the telomere length of 50-week-old chickens was half of that of 8-week-old chickens. There was also a significant difference in survival rates among the breeds. Both Rhode and Korean Ogye had the highest survival rates, while Cornish had the lowest. There was a significant positive correlation between survival rate and telomere length, and telomere length in old age showed a higher correlation with survival rate than that in young age. Therefore, it is considered that TSR is more closely related to survival rate than the telomere length. Based on the telomere dynamics and survival rates of 12 Korean native chicken breeds, it was concluded that the Rhode breed and Cornish breed had the highest and lowest vitality, respectively.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.2
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• pp.257-269
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• 1996

The puropose of this study was to investigate the movement-fitness according to the surface changing of lower limb The experimental items were divided into the lower limb movements (5) and body-shapes (7). This study was done by the expansion and contraction rate consideration of length, girth Also, the lower half of body shape-change on the movements and body-shapes by flat shell was done simultaneously. The summarized findings resulted from experiments and investigation are suggested as follows; First, when commpared the expansion and contraction rate of the length and girth items, the expansion rate of the back crotch length (14~20%), hip girth (10~ 21%) and knee girth (6.2~18.5%) in rabbit leap movement was the most notable among all variables considered in this experimentation. On the others hand, the front croth length (-22~-52%) contracted remarkably. And big-thigh type was the most notable on the body-shape comparision. Second, in comparision of the expansion and contraction rate of the area on the blocks, the expansion of the hip (50~200%) and knee (51~74%) block was the most remarkable. Especially, in the sit on knees movement of the hip-down type expanded 209.4%. Third, in comparision of the lower half of body shape-change, on the movements and body- shapes by the flat shell, under the influence of knee-joint and hip-joint the shape-changs of the hip and knee block was the most notable. But the shape-change of the waist, abdomen, calf, and ankle was feeble.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.1
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• pp.11-15
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• 2001

We present the design and strength evaluation of an anodically bonded pressurized cavity array, based on the energy release rate measured from the anodically bonded plates of two dissimilar materials. From a theoretical analysis, a simple fracture mechanics model of the pressurized cavity array has been developed. The energy release rate (ERR) of the bonded cavity with an infinite bonding length has been derived in terms of cavity pressure, cavity size, bonding length, plate size and material properties. The ERR with a finite bonding length has been evaluated from the finite element analysis performed for varying cavity and plate sizes. It is found that, for an inter-cavity bonding length greater than the half of the cavity length, the bonding strength of cavity array approaches to that of the infinite plate. For a shorter bonding length, however, the bonding strength of the cavity array is monotonically decreased with the ratio of the bonding length to the cavity length. The critical ERR of 6.21J/㎡ has been measured from anodically bonded silicon-glass plates. A set of critical pressure curves has been generated for varying cavity array sizes, and a design method of the pressurized cavity array has been developed for the failure-free wafer-level packaging of MEMS devices.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.8 no.1
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• pp.29-38
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• 1978

The purpose of this study is to obtain the enshortening and elongation rate of image in orthopantomograph. The subjects were consisted of 15 dry skulls attached with radiopaque materials on each anatomical points. The length measurements were performed between two points on dry skull, and between two points on film. The results are as follows: 1. The enshortening and elongation rate between two anatomical points (1) ANS↔infraorbital foramen (left:+1.3%, right:+0.7%) (2) ANS↔maxillary tuberosity(left:-11.7%, right:-14.3%) (3) Zygomatic arch length(left:-4.8%, right:-8.9%) (4) first molar↔infraorbital foramen (left:+19.8%, right:+24%) (5) inter-infraorbital foramen length(-21.4%) (6) inter-first molar length (-31.8%) (7) inter-mental foramen length(+1.4%) (8) mental foramen↔mandible angle (left:+3.3%, right:+3.3%) (9) mental foramen↔lingula(left:+8.2%, right:+3.3%) (10) mental foramen↔condyle head(left:+5.2%, right:+4.5%) (11) mandible↔condyle head (left:+15.4%, right:+16.4%) 2. The closer the object is to the occlusal plane and the median line, the smaller it appears.

• Journal of the Korean Solar Energy Society
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• v.29 no.5
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• pp.20-27
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• 2009

The effect of borehole thermal resistance on the borehole length is studied. In performing this work a new concept BLRR(borehole length reduction rate) is developed based on the line source model. The solution of line source model is shown to be valid through the comparison with the data of thermal response test. It is shown that BLRR is a function of soil thermal conductivity(k) and borehole thermal resistance($R_b$). The value of BLRR increases with increasing k, which means reducing $R_b$ is more effective when k is high. The reduction of borehole length with change of $R_b$ is easily estimated with BLRR. The validity of BLRR is also examined with EED analysis.