• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.165-173
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• 2015

This paper presents numerical results of static structural stability analysis in development of a vertical transfer device of a PRT(Personal Rapid Transit) vehicle. The vertical transfer of a fully occupied vehicle operating on a road network is the first attempt, which is expected to contribute to overcome the limitations of conventional 2-dimensional operation mode. In particular, the vertical transfer apparatus designed based on vertical circulating conveyors is capable of continuous transfer without time delay so that it enables to accommodate a high traffic density. This system has been frequently used in a logistics field; however, it is essential to assess a structural integrity because an external force by a vehicle weight is exerted on the conveyors in the form of a concentrated load unlike a conventional logistic transport. In this study, prior to the production process, the structural performance of the pilot design in an early stage is numerically evaluated using the commercial finite element method (FEM) solver (i.e., $Ansys^{(R)}$).

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.94-99
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• 2014

Recently, trends in new transportation system development have been primarily focused on sustainable and ecofriendly mobility solutions. The personal rapid transit (PRT) system has been considered a promising candidate in this category; its competitiveness is being improved through convergence with cutting-edge electric vehicle (EV) technologies. However, battery-powered vehicles pose difficult technical challenges in attempts to achieve reliable and efficient operation. In this study, a design approach for a solar-power assisted PRT system is presented with small-scale demonstrations aimed at circumventing challenges facing its adoption, as well as helping speed the transition to electric-powered ground transportation. From the results, it is expected that flexible photovoltaic (PV) cells will be able to supply 11% of the power required by the service equipment installed in a prototype vehicle. In particular, flexible photovoltaic (PV) cells are advantageous in terms of cost, weight, and design considerations. Most importantly, the cells' flexibility and attach-ability are expected to give them great potential for extended application in various areas.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.139-155
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• 2024

Using the cytb gene region of the mitochondrial DNA of eight populations of Sarcocheilichthys nigripinnis morii and five populations of S. variegatus wakiyae, which belong to the genus Sarcocheilichthys from Korea, the genetic diversity and molecular phylogenetic relationships of each population were examined. As a result of the analysis, it was confirmed that the S. variegatus wakiyae population had higher genetic diversity than the S. nigripinnis morii population. In the phylogenetic tree of genus Sarcocheilichthys fish in Korea based on the cytb gene, the Yeongsan River (YSR) population of S. variegatus wakiyae forms a clade with the Tamjin River (TJR), Yeongsan River (YSR), and Seomjin River (SJR) population of S. nigripinnis morii, and genetic relationships that do not align with the current classification system were observed. Meanwhile, on the nuclear DNA phylogenetic tree, S. variegatus wakiyae and S. nigripinnis morii could be clearly distinguished, showing mitonuclear inconsistency where mitochondrial and nuclear DNA conflicted on the phylogenetic tree. The Seomjin River (SJR) population of S. nigripinnis morii was translocated to the Dongjin River (DJR) population, haplotype from which crossbreeding was presumed to have occurred was confirmed. Among the rivers flowing into the East Sea, the S. nigripinnis morii population is known to have been introduced and inhabit only the Hyeongsan River (HSR), and it is presumed to be a population formed by translocation from the Han River (HR) population, with a haplotype representing a unique genetic group also confirmed. The Han River (HR), Geum River (GR), and Mangyeong River (MGR) populations of S. nigripinnis morii formed a genetically identical population with S. czerskii and S. soldatovi distributed north of the Yalu River, and accordingly, a taxonomic reexamination was required through morphological and molecular phylogenetic studies by securing various specimens.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.2
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• pp.155-169
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• 2007

A transport container for a 500 kCi tritium storage vessel was developed, which could be used for the transport of metal tritide from Wolsong TRF facility to a disposal site. The structural, thermal, shielding, and confinement analyses were performed for the container in a view of Type B. As a result of structural analysis, the developed container sustained its integrity under normal and accidental conditions. The maximum temperature increase of the inner storage vessel by radiation was evaluated at $134.8^{\circ}C at room temperature. In $800^{\circ}C$ fire test, The thermal barrier of container sustained the inner vessel at $405^{\circ}C after 30 min, which temperature was allowable for the container integrity since maximum design temperature of inner vessel was $550^{\circ}C. In the evaluation of the shielding, the activity of radiation was nearly zero on the outer surface of inner vessel. Consequently the transport container for a 500 kCi tritium was evaluated to pass all the safety tests including accidental condition, so it was concluded that the designed transport container is proper to be used.

• Korean Journal of Environment and Ecology
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• v.31 no.5
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• pp.461-471
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• 2017

Population genetic studies of 10 groups of Iksookimia pacifica were conducted to investigate the genetic diversity and population genetic structure across its known range in South Korea. Population DNA sequences of one mitochondrial gene (mtCOI) and three nuclear genes (IRBP, EGR2B, RAG1) were examined in samples collected from ten streams that flow into the East Sea. Both mitochondrial and nuclear sequences exhibited significant differentiation among populations except a few cases. The Bayesian analysis of the multi-locus genotypes inferred from the DNA sequences of nuclear genes clustered the individual fish largely into two geographical groups: a northern group (from Baebong stream to Cheonjin stream) and a southern group (Yangyangnamdae stream to Gangneungnamdae stream). Given that the streams flowing into the East Sea are geographically isolated water systems, such separation of genotypes can be interpreted by the geographical separation of common ancestors into north and south that had colonized South Korea. Since the initial geographical separation of the ancestral population by north and south, the ancestral groups seem to have experienced further differentiation into the current genetic clusters through the physical isolation of streams by the East Sea in each region. It is notable that many individuals in the Jasan stream formed a genetic cluster with those of Yangyangnamdae and Gangneungnamdae streams which are distant from each other. In addition, mitochondrial gene showed low genetic differentiation between some neighboring populations and very low level of genetic diversity in several populations. The present population genetic study will provide valuable information for the conservation and management of the Korean endemic fish species, I. paicifica.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.351-358
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• 2016

An Electrical Point Machine (NS:New-type Switch), which is equipped and operated at railways in Korea, has been used since the 1960s after being imported from Japan. On the other hand, although the mechanical configuration has improved the position motor control circuit, the electrical connection has not been improved, so NS may have a problem, such as the interlocking system of automatic train operation. In addition, NS is the most vulnerable part in the railway system and a huge train accident may occur due to minor defects. The existing NS wiring set of the circuit controller should be checked only if fixed. Therefore, an excessive inspection time only by a Railroad Signal expert is required. In this paper, the improvement of electrical connection in a NS wiring set, such as the position motor control circuit, was developed and the prototype was installed at Seoul Metro in the distance to go section. The results can be used to help make appropriate adjustments. The improvement of the NS wiring set enhance the maintenance efficiency, passenger service and the stability of the signal system as well as reducing the maintenance cost.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.242-246
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• 2017

The application of composite cathode materials including $LiFePO_4$ (lithium iron phosphate) of olivine crystal structure, which has high thermal stability, were investigated as alternatives for hybrid battery-capacitors with a $LiMn_2O_4$ (spinel crystal structure) cathode, which exhibits decreased performance at high temperatures due to Mn-dissolution. However, these composite cathode materials have been shown to have a reduction in capacity by conducting life cycle experiments in which a $LiFePO_4$/activated carbon cell was charged and discharged between 1.0 V and 2.3 V at two temperatures, $25^{\circ}C$ and $60^{\circ}C$, which caused a degradation of the anode due to the lowered voltage in the anode. To avoid the degradation of the anode, composite cathodes of $LiFePO_4/LiMn_2O_4$ (50:50 wt%), $LiFePO_4$/activated carbon (50:50 wt%) and $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ (50:50 wt%) were prepared and the life cycle experiments were conducted on these cells. The composite cathode including $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ of layered crystal structure showed stable voltage behavior. The discharge capacity retention ratio of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ was about twice as high as that of a $LiFePO_4/LiMn_2O_4$ cell at thermal stability experiment for a duration of 1,000 hours charged at 2.3 V and a temperature of $80^{\circ}C$.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.165-171
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• 2020

This study examined the relationship between chronic kidney disease (CKD) and the homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function (HOMA-B) in non-diabetic Korean adults. This study included 4,380 adults aged 20 or older (50.32±16.14) using the 2015 Korea National Health and Nutrition Examination Survey (KNHANES) data, which represents the national data in Korea. The present study had several key findings. First, in terms of HOMA-IR, after adjusting for the related variables (Model 4), the HOMA-IR (M±SE, 95% confidence interval [CI]) in group 1 (G1; estimated glomerular filtration rate [eGFR], ≥90 mL/min/1.73 ㎡), group 2 (G2; eGFR, 60~89 mL/min/1.73 ㎡), group 3a (G3a; eGFR, 30~59 mL/min/1.73 ㎡), and ≥group 3b (≥G3b; eGFR, <30 mL/min/1.73 ㎡) were 1.78±0.03 (1.73~1.83), 1.87±0.03 (1.81~1.93), 2.16±0.13 (1.91~2.42), and 2.59±0.24 (2.12~3.06), respectively. The HOMA-IR was positively associated with the progression of CKD (P<0.001). Second, in terms of the HOMA-B, after adjusting for the related variables (Model 4), the HOMA-B (M±SE, 95% CI) in G1, G2, G3a, and ≥G3b were 87.46±1.21 (85.08~89.84), 89.11±1.38 (86.40~91.81), 104.82±5.91 (93.23~116.42), and 123.97±10.87 (102.66~145.29), respectively. HOMA-B was positively associated with the progression of CKD (P<0.001). Both insulin resistance and the beta-cell function were positively associated with CKD in non-diabetic Korean adults.

• Journal of Yeungnam Medical Science
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• v.13 no.2
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• pp.199-210
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• 1996

Infantile hypertrophic pyloric stenosis(IHPS), which occurs three of 1,000 live births, is a major cause of nonbilious vomiting of early infancy but its etiology and pathogenesis are still obscure. The operation of pyloromyotomy as described by Ramstedt in 1912 remains the standard of care for the treatment of IHPS. From January 1993 to October 1996, 35 infants with IHPS were surgically treated and the following results were obtained. 1. Thirty-five patients comprised 32 males and 3 females, and the ratio of male to female was 10.7:1. 2. The most prevalent age group was between 2 weeks and 8 weeks. 3. Of 35 infants, first born babies were 23 cases(65.7%). 4. Breast feeding was in 23 cases(65.7%). 5. The body weight percentile at admission was lower than 50 percentile in all 35 cases. 6. Onset of symptoms was predominantly between 1week and 2 weeks in 11 cases(31.4%). 7. All had a history of nonbilious vomting, generally projectile in nature. 8. In the measured serum electrolytes, hypokalemia was noted in 9 cases(25.7%), hypochloremia was observed in 14 cases(40.0%). 9. In the preoperative ultrasonography, the average muscle thickness, diameter, and length of the pylorus were 6.2mm, 12.1mm, and 17.9mm, respectively. 10. Among 35 cases, significant sonographic criteria of IHPS, muscle thickness of 5mm or more, were noted in 26 cases(83.9%). 11. A total of seven associated anomalies were noted in six patients. 12. All 35 cases were treated with Fredet-Ramstedt pyloromyotomy. 13. There were postoperative complications of wound infection in 2 cases. Intermittent nonprojectile vomiting was presented in 8 cases(22.9%) after operation, but one of them was relieved in 13 days and the rest were relieved within one week by adjustment of oral intake.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.878-887
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• 2012

This study investigated the fermentative characteristics and immunomodulating activity in Kimchi added with various salts (salt replacement and herb-salt with Acanthopanax senticosus and Glycyrrhizae uralensis) for the reduction of Na concentration in Kimchi. Kimchi using a salt replacement and herb-salt showed a higher level of acidity (0.8~0.84%) than that of the control (0.7%) at 7-day fermentation. Kimchi using a salt replacement and herb-salt showed a lower level of salinity (1.72~1.98%) than that of control (2.3~2.57%) during fermentation. The growth of Lactobacillus spp. and Leuconostoc spp. recorded the highest level ($2.3{\times}10^8$ and $2.8{\times}10^6cfu/g$, respectively) in control at 6 day-fermentation. However, those levels in Kimchi prepared with salt replacement and herb-salt were $3.5{\sim}5.4{\times}10^8$ and $6.1{\times}10^6cfu/g$, respectively. It is assumed that the high level of acidity of Kimchi prepared with salt replacement and herb-salt was caused by the increase in the growth of Lactobacillus spp. and Leuconostoc spp.. When the macrophage stimulating activity of salt replacement kimchi (Salt-R kimchi) supplemented with hot-water extract from Acanthopanax sentisus (AS) or Glycyrrhiza uralensis (GU) was investigated on aging period, Salt-RA kimchi with AS 5% at 6 days (2.78-fold of saline control at $100{\mu}g/m{\ell}$) and Salt-RG kimchi with GU 5% at 9 days (2.02-fold) significantly increased compared to the Salt-RA kimchi without AS or GU. In addition, Salt-RAG kimchi with AS 3% and GU 3% improved the bitter taste of Salt-RA and potently stimulated the macrophage at 6 days (1.28-fold of Salt-R kimchi) even though its activity was lower than Salt-RA (5%, 1.39-fold).