• Journal of Korean Academy of Nursing
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• v.23 no.2
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• pp.207-223
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• 1993

Inpatients are mostly occupied in bed with restricted activity, nearly all patient populations are at risk for the occurrence of skeletal muscle atrophy due to decreased level of activity. Restriction of mobility is far greater in pediatric patients compared with adult patients since almost all the activities of daily living is performed by parents or caregivers. It could be assumed that pediatric patients are more vulnerable to skeletal muscle atrophy than adult patients, however, there have been no attempts to reduce the atrophy of developing muscle. Therefore it is important to determine the effect of exercise in developing muscle during decreased activity. The purpose of this study was to determine the effect of periodic weight support during hindlimb suspension on the mass and cross-sectional area of Type I and II fibers in developing soleus(Type I ) muscle. To examine the effectiveness of periodic weight support activity in maintaining mass and fiber size. the hindlimb of young female Wistar rats was suspended(HS) and half of these rats walked on a treadmill for 45min / day(15min every 4h) at 5m / min at a 15 grade(HS-WS). After 7days of hindlimb suspension, soleus wet weight was 28. 57% smaller and relative soleus weight was 28. 21% smaller in comparison with con-trol rats (p〈0.05) Soleus wet weight and relative soleus weight increased by 67.72% and 71.43% each with periodic weight support activity during hindlimb suspension (p〈0.01, p〈0.005), moreover soleus wet weight and relative soleus weight of the HS -WS rats were greater than those of the control group. No change was observed in fiber type percentage of the developing soleus muscle after 1 week of hindlimb suspension plus weight support activity. Type I and II fiber cross-sectional areas of the developing soleus muscle were 50.45% and 43.39% lower in the HS group than in the control group (p〈0.0001), type I and II fiber cross-sectional areas of the developing soleus were 24.49% and 29.93% greater in the HS - WS group than in the HS rats (p〈0.0001), whereas Type I and II fiber cross-sectional areas of HS - WS group were less than those of the control group, The results suggest that periodic weight support activity can ameliorate developing soleus muscle atrophy induced by hindlimb suspension, even in type II fibers that would not have been expected to be recruited by this type of neuromuscular demand. Clinical experimental study is needed to deter-mine the effect of periodic weight bearing exercise on developing atrophied leg muscle based on these results.

• Tribology and Lubricants
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• v.25 no.4
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• pp.217-224
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• 2009

In this study, friction tests were carried out in order to investigate the friction behavior of textured surface in unlubricated state using ball-on-disk type apparatus. Test specimens were SUJ2 bearing steel ball and SM45C steel disk. Square arrays of circular micro-dimples were created on the surface of disk specimen by Nd:YAG Laser. Friction tests were performed for the disk specimen with various micro-dimple parameters and was also conducted for the variation of normal loads and relative velocities. The results showed that fiction coefficient of textured surface was lower than that of non-textured surface and the deeper depth of micro-dimple was, the lower friction coefficient obtained at the same diameter of micro-dimple in unlubricated state. Area density of micro-dimple had an effect on the friction coefficient. It was also found that friction coefficient generally decreased with the increase of normal load and relative velocity.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.6
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• pp.858-866
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• 1998

Soldering is the usual method used to correct an unstable fixed partial denture framework at patient's try-in; However, presoldering base metal alloys is technique-sensitve and results are unstable because it is difficult to maintain uniform heat distribution and to prevent oxidation of an alloy. A cast-joining technique has been developed by Weiss and Munyon for repair, correction and addition to base metal framework. This joining technique eliminates the problem with presoldering of non-precious frameworks. The object of this study was to 1) compare the relative flexure strength and the joining effectiveness of Ni-Cr-Be cast in two pieces and 'pre-soldered' versus in two pieces and 'cast-joined'. 2) determine the effect of increasing the number of retentive grooves on the face of the cast and 3) determine the effect of the relative matched position of groove patterns on flexure strength. The joining effectiveness can be expressed by the ratio of the mean flexure stress of soldered or cast-joined specimens to that of one-piece cast. Resin rods 3mm in diameter were used as pattern of specimens for one-piece casted, presoldered, and cast-joined groups. Cast-joined specimens had two different patterns of retentive grooves on the joined faces. Type A had cross-shaped grooves 1mm in depth. 0.6mm in width. Type B was the same except for the addition of one more retentive groove. In the experiment connecting cast-joined specimens, half of specimens with type A pattern had their patterns on the faces of paired casts matched with each other as mirror image. With the rest pairs, it was proceeded that one of paired casts turned 45 degrees so that the patterns crossed. Half of specimens with type B pattern also had the patterns matched as mirror image; However, here, one of paired casts turned 90 degrees with the other pairs. Retentive groove in this study lacked the intentional undercuts, in contrast with the suggestion of Weiss and Munyon. The specimens were subjected to four-point flexural loading in an Instron testing machine. The midspan flexural stress was calculated at the point of initial plastic strain as determined from a strip-chart recorder or at the point of failure if this occured at a lower stress level. Within the scope of this study, the following results were obtained. 1. The presoldered group showed flexural strength at least 2 times higher than the cast-joined groups. Its joining effectiveness was 82%. 2. In cast-joined groups, the flexural strength of joints with type B patterns exhibited 1.5 times that of joints with type A patterns. Joining effectivenesses were 38% for type B patterns, 25-26% for type A patterns. 3. The relative matched position of groove patterns did not have any significant effect on flexural strength of the cast-joined specimens with either type A patterns or type B patterns(p>.05).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.5
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• pp.332-335
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• 2005

The three Korean wheat cultivars with different plant types; the erect, the middle and the creeping growth habit, were studied for their utilization to solar radiation, temperature changes on the furrow and to provide optimum planting space for producing the high yield in 2003. The average solar radiation rate was lowest for creeping type ($39.2\%$) and highest for erect type ($75.8\%$) The correlation coefficient between the coverage rate and the solar transmission rate was r = 0.8624 which was significant at $5\%$ level. The relative growth of the plant, tiller rate and leaf size was increased in the erect and the middle type at lower plant density, while no change on plant growth at creeping type regardless of plant density. The increase of leaf size in the lower plant density was due to longer flag and the first leaf than those of other plant types. The temperature on the furrow of growing plants was changed by the canopy. The changes in temperature pattern on the furrow according to plant types during winter season was different compared to the non plant ground. The temperature of the nonplant ground was the lowest due to solar reduction increasing the amount of cool air flowing in the furrow.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.1
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• pp.8-13
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• 2005

In order to analyze the properties of domestically produced 36,000lb porcelain insulators by change of the alumina addition to raw materials, 36000lb ball socket type suspension insulators that were manufactured in 1989, 1995 and 2001 were removed from transmission lines and an experiment was performed. The results indicated that 8 [wt.%] alumina, which influences the mechanical properties and arc resistance properties in the case of insulators that were manufactured in 1989 was contained, and the relative density and the fracture toughness of insulators appeared by 94.2% and 1.4 [MpaㆍM/sup 1/2/], respectively. However, 12 [wt.%] alumina was contained in the case of insulators that were manufactured in 1995, and the relative density and the fracture toughness of insulators appeared preferably lower by 92% and 1.3 [MpaㆍM/sup 1/2/], respectively. The greatest amount of alumina was contained by 17 [wt.%] in the case of insulators that were manufactured in 2001. It was confirmed that the electrical and mechanical characteristics such as the relative density and the fracture toughness appeared remarkably by 96% and 1.7 [Mpaㆍm/sup 1/2/], respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.390-395
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• 2004

In order to analyze the physical and chemical characteristics of home production porcelain insulators by change of the alumina addition amount, 360001bs ball socket type suspension insulators which were manufactured in 1989, 1995 and 2001 removed in transmission line and an experiment was performed. By the result, 8 wt.％ alumina that influences the mechanical properties and arc resistance properties in case of insulators that were manufactured in 1989 was contained, and the relative density and the fracture toughness of insulators appeared by 94.2％ and 1.4 ㎫$.$ $M^{\frac{1}{2}}$, respectively. However, 12 wt.％ alumina was contained in case of insulators that were manufactured in 1995, and the relative density and the fracture toughness of insulators appeared preferably lower by 92％ and 1.3㎫$.$ $M^{\frac{1}{2}}$, respectively. Amount of alumina was contained most by 17 wt.％ in case of insulators that were manufactured in 2001. It was confirmed that the electrical and mechanical characteristics such as the relative density and the fracture toughness appeared excellently by 96％ and 1.7㎫$.$ $m^{\frac{1}{2}}$, respectively.

• Clinical and Experimental Pediatrics
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• v.58 no.2
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• pp.52-59
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• 2015

Purpose: This study aimed to investigate the relative weight gain at 2-week intervals up to 6 weeks after birth to predict retinopathy of prematurity (ROP) requiring treatment among very low birth weight infants. Methods: A total of 211 preterm infants with birth weights <1,500 g and gestational age <32 weeks were retrospectively reviewed. The main outcome was the development of ROP requiring treatment. Body weight measurements were recorded daily. Relative weight gains (g/kg/day) were calculated at the second, fourth, and sixth week after birth. Results: Of the 211 infants, 89 developed ROP, of which 41 spontaneously regressed and 48 with early treatment of ROP type I required laser treatment. The relative weight gain at 2, 4, and 6 weeks postnatal age was significantly lower in infants with ROP requiring treatment than in infants without ROP or those with spontaneous regression (P<0.001, P=0.005, and P=0.004, respectively). On logistic regression, poor relative weight gain in the first 2 weeks was found to be related to ROP requiring treatment (adjusted odds ratio, 0.809; 95% confidence interval, 0.695-0.941; P=0.006). Relative weight gain at 2 weeks postnatal age was significantly lower in infants with ROP requiring treatment compared to that in ROP requiring no treatment (P=0.012). Conclusion: Poor postnatal weight gain in the first 2 weeks of life is an important and independent risk factor for ROP requiring treatment. Postnatal weight gain can predict the development of severe ROP requiring treatment.

• Journal of the Korean Statistical Society
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• v.19 no.1
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• pp.24-44
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• 1990

The purpose of this paper is to extend the idea of Tamhane and Bechhofer (1977, 1979) concerning the normal means problem to some general class of distributions. The key idea in Tamhane and Bechhofer is the derivation of the computable lower bounds on the probability of a correct selection. To derive such lower bounds, they used the specific covariance structure of a multivariate normal distribution. It is shown that such lower bounds can be obtained for a class of stochastically increasing distributions under certain conditions, which is sufficiently general so as to include the normal means problem as a special application. As an application of the general theory to the scale parameters problem, a two-stage elimination type procedure for selecting the population associated with the smallest variance from among several normal populations is proposed. The design constants are tabulated and the relative efficiencies are computed.

• Journal of the Ergonomics Society of Korea
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• v.26 no.4
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• pp.91-101
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• 2007

The purpose of this study is to propose an optimal layout for the accelerator and brake pedals in sedan and SUV, and also to compare the pendant-type pedal with organ-type pedal. 12 male subjects participated in the experiment, the subjects were divided into 3 groups according to height percentile(under 50%ile, 50%ile to 75%ile, over 75%ile). Independent variables were seat height (H₃₀), X and Y coordinates of the center of accelerator and brake pedals and the x and y relative distance between two pedals. Dependent variable was subjective ratings for lower body discomfort. The response surface methodology using a central composite design was employed to develop a prediction model for lower body discomfort of each pedal. It is noticeable that the lateral position of the accelerator in all groups was not statistically significant. The optimal locations of both pedals were found to be distinct according to the percentile of subjects. X distance from accelerator to brake of both-type pedals is similar. But Y distance from accelerator to brake of organ-type is less about 2-3cm than that of pedant-type.

• Ocean and Polar Research
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• v.25 no.4
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• pp.557-567
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• 2003

High-resolution (3.5 kHz) subbottom profiles were analyzed in order to reveal sedimentation pattern of late Quaternary in the northern South Shetland continental margin and the South Scotia Sea, Antarctica. On the basis of clarity, continuity and geometry of surface and subbottom echoes together with seafloor topography, high-resolution echo characters are classified into eight echo types which represent rock basements (echo type III-1), coarse-grained subglacial till or moraine (echo type I-1), slides/slumps (echo type IV), debris-flow deposits (echo types II-3 and III-2), and bottom-current deposits (echo types I-2, II-1 and II-2). Subglacial till or moraine (echo type I-1) is mostly present in the lower continental shelf and upper continental slope of the northern South Shetland continental margin, which changes downslope to slides/slumps (echo type IV) and debris-flow deposits (echo types II-3 and III-2) in the middle to lower continental slope. This distribution suggests that the continental slopes of the northern South Shetland continental margin were mostly affected by downslope gravitational processes. Further downslope, bottom-current sediments (echo type I-2) deposited by the southwestward flowing Antarctic Deep Water (ADW) occur at the South Shetland Trench, reflecting an Interaction between mass flows and bottom currents in the area. In contrast to the northern South Shetland continental margin, the South Scotia Sea is dominated by bottom-current deposits (echo types II-1 and II-2), indicating that the sedimentation was mostly controlled by the westward flowing ADW. Flow intensity of the ADW has increased in the relative topographic highs, forming thin covers of coarse-grained contourites (echo type II-1), whereas it has decreased in the relative topographic lows, depositing thick, fine-grained contourites (echo type II-2). The poor development of wave geometry in the fine-grained bottom-current deposits (echo type II-2) is suggestive of the unsteady nature of the ADW flow.