• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.89-95
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• 2013

A DBLP(Double blind light pipe) daylight system can be installed at a building exterior wall or roof to replace artificial light during the day time. This system was consisted of a double blind light collector, a mirror duct type light transformer and a prism light pipe distributor. The double blinds were used to track the sun's altitude and azimuth movements to collect the sunlight throughout the day. The sunlight collected by the light collector was reflected on the first mirror and the second mirror and sent to the light pipe through the light transformer. The transformer was designed to deliver the sunlight into the light pipe efficiently. The light distributor plays a role in diffusing the sunlight coming in through the light collector to be used for indoor lighting. In this paper, a DBLP system has been designed, installed and tested at a KIER daylighting twin test cell. The DBLP daylighting system was applied to the experimental test cell which has an indoor area of 2.0 m wide ${\times}$ 2.4 m height ${\times}$ 3.8 m length. The experiment was conducted from January 30 to February 27, 2012, under clear skies and partially cloudy skies. Data was collected from 10:00 am to 16:00 pm every 2 minute and the average was calculated for every 30 minute of the data collection to obtain the system efficiency. The results indicated that the DBLP system efficiency was evaluated as 11.67%. The DBLP system indoor illumination energy reduction was predicted as 0.822 kWh/day. This could replace 4 sets of a 32W fluorescent lamp operating 6.4 hours per a day.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.2
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• pp.66-78
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• 2021

In this study, the effect of Symmetry Breaking was compared according to the equivalent ratio condition and the number of nozzles where combustion instability occurs in an annular combustor. Generally, due to the relatively short combustor length, a longitudinal instability was less likely to occur in the annular combustor, but the combustion instability sometimes happens when ducts such as transition piece in gas turbine power station are present. In this case, due to the duct, only the longitudinal instability mode is observed. The characteristics of Symmetry Breaking were investigated according to the number of five lean nozzles and the equivalent ratio combination, and as the equivalent ratio decreased, the effect of Symmetry Breaking rapidly occurred, and the instability was dramatically disappeared and the amplitude was greatly reduced. In addition, it was confirmed that as the number of lean nozzles increased, a phenomenon such as a reduction in the equivalent ratio appeared.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.4
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• pp.372-379
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• 2023

Backgrounds/Aims: While single-incision laparoscopic cholecystectomy (SILC) has advantages in cosmesis and postoperative pain, its utilization has been limited. This study raises the possibility of expanding its indication to acute cholecystitis with the novel method of solo surgery under retrospective analysis. Methods: We compared the outcomes of SILC (n = 58) to those of three-incision laparoscopic cholecystectomy (TILC; n = 117) for acute cholecystitis, being performed from March 2014 to December 2015. Results: Intraoperative results, including the operation time, did not differ significantly, except for drain catheter insertion (p = 0.004). Each group had 1 case of open conversion due to common bile duct injury. There was no significant difference in the length of hospital stay. Either group by itself was not a risk factor for complications, but in preoperative drainage for intraoperative perforation, 3 factors of intraoperative perforation, biliary complication, and history of upper abdominal operation for additional port, only American Society of Anesthesiology (ASA) scores for postoperative complication of Clavien-Dindo grades III and IV were significant risk factors. Conclusions: Our study findings showed comparative outcomes between both groups, providing evidence for the safety and feasibility of SILC for acute cholecystitis.

• Korean Journal of Plant Resources
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• v.22 no.1
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• pp.31-36
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• 2009

The aim of this study was to examine geographic variation to support a genetic resource conservation plan of rare endemic Picea jezoensis (Siebold & Zucc.) Carriere. Three populations of P. jezoensis were analysed using multivariate analysis for 7 characteristics of needle morphology. In the morphological characters, seven characters of needle were 15.11 mm (needle length), 1.43 mm (needle width), 0.42 mm (needle thickness), 10.9 (length / width of needle), 3.6 (width / thickness of needle), 0.47 mm (Distance between resin duct and vascular), 17.4 ea. (number of stomata row), respectively. Nested analysis showed that were statistically significant differences among populations as well as among individuals within populations in 6 quantitative characters. In 5 of 7 characters, variance components among populations were higher than those among individuals within populations. Cluster analysis using complete linkage method showed two groups (Mt. Gyebang populations was genetically distinct from the other two populations) to Euclidean distance 0.4. Among principal components, primary 2 principal components appeared to be major variables because of the loading contribution of 100%.

• Development and Reproduction
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• v.12 no.3
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• pp.215-220
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• 2008

Sex differentiation process of the spotted Black Bullhead, Pseudobagrus koreanus, was investigated using fish samples of different age after hatching. The primordial germ cells appeared separately under air bladder in 1-day larva (total length: $6.63{\sim}6.95\;mm$). The primordial gonad with a genital ridge developed in 5-day prelarva ($7.50{\sim}9.36\;mm$). The ovarian differentiation started in about 25-day juvenile ($11.58{\sim}13.21\;mm$). The somatic tissues enlongated in the tip of one end of undifferentiated gonad and fused each other. Thus a small ovarian cavity appeared. The testicular differentiation was initiated in 30-day juvenile ($12.19{\sim}13.72\;mm$). The rudiment of sperm duct was appeared in the lower part of the undifferentiated gonad. In 50-day juvenile ($16.28{\sim}17.06\;mm$), the ovary started to fill with peri-nucleolus oocytes, and the spermatogonia started to develop. In 250-day juvenile ($35.49{\sim}51.12\;mm$), the ovary became bigger and filled with oocytes, and the number of spermatogonia started to increase. Considering these results, the spotted Black Bullhead could be a differentiated type in sex differentiation and gonochorism in sexuality.

• Development and Reproduction
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• v.4 no.2
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• pp.195-201
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• 2000

Sex differentiation process of the spotted sea bass, Lateolabrax maculatus, was investigated by histological method. The fish samples were collected from just after hatching to 365 days later. The primordial germ cells and genital ridge were appeared separately hanging under air bladder in 30-day larva (total length: 11.7~13.2 mm), and were unified into the undifferentiated gonads in 40-day larva (12.5~14.0 mm). The ovarian differentiation was started in 60-day juvenile (23.6~27.0 mm). The somatic tissues were elongated in tip of both ends of undifferentiated gonad and were fused each other. The complete ovarian cavity was appeared in 80-days juvenile(33.1~42.5 mm). The testicular differentiation was initiated in 70-day juvenile (24.8~31.6 mm). The rudiment of sperm duct was appeared in the center of the undifferentiated gonad. The meiosis of germ cells in the ovary was started in 168-day juvenile (88.0~115.4 mm). In 287-day juvenile (175.1~233.6 mm), the ovary was filled with both of chromatin stage and perinucleolus stage oocytes. The meiosis of male germ cells was started in 245-day juvenile (124.4~168.3 mm). However, the seminiferous tubules of testis were filled with numerous sperm in 365-day juvenile (162.5~253.8 mm). The sex ratio of male and female was 1:1.38. Considering these results, the spotted sea bass was showed differentiated type in sex differentiation and gonochorism in sexuality.

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.379-385
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• 2009

Tetragomphius procyonis Baylis & Daubney, 1923 were obtained from the pancreatic duct of a naturally infected Eurasian badger, Meles meles, which was submitted to animal hospital for parasitic diagnosis from Gyeryongsan National Park in Korea. The hookworms were examined by light and scanning electron microscope. The length of body measured male 15.0-18.8 mm, female 21.5-25.5 mm, respectively. In both sex, the ventral cutting plates of oral margin are much reduced and elongated latero-dorsally, the dorsal cutting plate is located long follow doral margin of the oral opening. The buccal capsule is cup-shaped and thicken with four cusped tooth at its base. The copulatory bursa has elongated ventral lobes and their large rays are parallel, while the dorsal lobe with its supporting rays is slightly split in two. The slender spicules are filariform and very long (8.7-9.3 mm), and their tips are fused together. The hookworm has following characters: dorsal cone on the both sex, gubernaculum on the male and terminal spine on the female tail absent; vulva is opening in the juction of the fourths and fifths of the body; dorsal ray with two long stems. The eggs from the uterus are 16 cell stages and those from the rectal feces, 32 cell stages. The size of eggs is 77.48-83.45 ${\times}$ 50.75-63.38 ${\mu}m$.

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.53-57
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• 2011

The present study has been carried out to analyze the flow characteristics of a heat recovery steam generator with the change of inlet flow conditions by using numerical flow analysis. The inlet of HRSG corresponds the outlet of gas turbine exit and the flow after gas turbine has strong swirl flow and turbulence. The inlet flow condition of HRSG should be included the exit flow characteristics of gas turbine. The present numerical analysis adopted the flow analysis result of gas turbine exit flow as a inlet flow condition of HRSG analysis. The computational flow analysis result of gas turbine exit shows that the maximum axial velocity appears near circular duct wall and the maximum turbulent kinetic energy and dissipation rate exist relatively higher gradient region of axial velocity. The comparison of flow analysis will be executed with change of inlet turbulent flow condition. The first case is using the inlet turbulent properties from the result of computational analysis of gas turbine exit flow, and the second case is using the assumed turbulent intensity with the magnitude proportional to the velocity magnitude and length scale. The computational results of flow characteristics for two cases show great difference especially in the velocity field and turbulent properties. The main conclusion of the present study is that the flow inlet condition of HRSG should be included the turbulent properties for the accurate computational result of flow analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.878-885
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• 2008

The FPDs(Flat Panel Displays) such as LCD(Liquid Crystal Display) and PDP(Plasma Display Panel) and OLED(Organic Light Emitting Diode), recently, have been substituted for CRT(Cathode Ray Tube) displays because they have a convex surface, small volume, light weight and lower electric power consumption. The productivity of FPDs is greatly dependent on the area of thin glass panel with 0.6 - 0.8mm thickness because FPDs are manufactured by cutting a large-scaled thin glass panel with patterns to the required product dimensions. So FPD's industries are trying to increase the area of thin glass panel. For example, the thin glass panel size of the 8th generation is 2,200mm in width, 2,600mm in length and 0.7mm in thickness. The air flows both in the thin glass panel and in the porous PE-plate surface were modeled and analyzed, from which a working condition was estimated. The thin glass panel on the porous PE-plate surface with self-lubricating characteristics was investigated and compared with that on the square duct floating bar surface with many holes of 1mm diameter when the thin glass panel contacts the floating bar surface due to malfunction of electric power supply.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.44-50
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• 1996

Sex differentiation in the rockfish, Sebastes schlegeli, was studied by using a histological method for the appearance of primordial germ cell, formation of primitive gonad and differentiation of female and male. The primordial germ cells were buried under fibrous mesenchymal tissue between gut and mesonephric duct of pre-larva with a total length (TL) of 6.3 mm at 2 days after parturition. In juvenile of TL $5.2\~5.9cm$ at 65 days after parturition, the gonad composed of a large number of genial cell and formed of cavity along the lateral side of the gonad, differentiated to the ovary. At this time, the gonad formed seminiferous tubules by somatic cells, differentiated to the testis. In juvenile of TL $7.0\~7.2cm$ cm at 115 days after parturition, gonads divided into testis contained pigment cell and ovary absent pigment cell. S. schlegeli differentiated directly into male or female without an intermediate female phase at early indifferentiated stage. Therefore, S. schlegeli belongs to the differentiated type of gonochoristic teleosts. At 350 days after parturition, sex ratio was approximately 1 : 1(p>0.05).