• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.5
• /
• pp.419-426
• /
• 2018

For an orbit transfer in a space exploration mission, a solid or liquid rocket booster is included at the last stage of the launch vehicle. During the orbit transfer, thrust misalignment can cause a severe orbit error. Three axis attitude control or spin stabilization can be implemented to minimize the error. Spin stabilization technique has advantages in structural simplicity and lightness. One of ways to apply the spin stabilization to the payload is to include a spin table system in the launch vehicle. In this paper, effect of the spin table system on separation dynamics of the payload is analyzed. Simple model of the spin table to mimic basic functions is designed and simulation environment is established with the model. Effect of the spin table is tested by evaluating separation dynamics of a payload with and without the spin table. Analysis on tolerance effect of separation spring constant on separation dynamics of a payload is conducted.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.12
• /
• pp.9-16
• /
• 2017

In this paper, the aerodynamic design process of wind turbine blades is established. The optimization design strategy is presented and the constraints that must be reviewed during the aerodynamic design process are summarized. Based on this, this study developed a BEMT-based aerodynamic optimal design program that can be applied easily to actual work, not only for research purposes, but also can be integrated from the initial concept design stage to the final 3D shape detail design stage. The developed program AeroDA consisted of a concept design module, basic design module, optimal TSR module, local shape optimization module, performance analysis module, design verification module, and 3D shape generation module. Using the developed program, an improved design of the 5MW blade by NREL was made, and it was confirmed that this program could be used for design optimization. In addition, a 10kW blade aerodynamic design and turbine detailed performance analysis were carried out, and it was verified by a comparison with the commercial program DNVGL Bladed.

• The Korean Journal of Pesticide Science
• /
• v.11 no.4
• /
• pp.254-260
• /
• 2007

In order to evaluate the toxic effects of butachlor, a herbicide widely used for control of weeds in paddy field, on medaka (Oryzias latipes), acute toxicity tests for five developmental stages and early life stage toxicity test of were conducted. As the results of acute toxicity test, $96h-LC_{50}s$ for 1 day, 1 week, 2 weeks, 2 months and 5 months after hatching of O. latipes were 0.68, 0.52, 0.38, 1.09 and $0.45\;mg\;L^{-1}$, respectively. This indicated that the most sensitive stage was 2 weeks after hatching. The early life stage toxicity test showed that no statistically significant hatching period and hatching success of embryo was observed at all concentrations of butaclor. However, 0.05 and $0.1\;mg\;L^{-1}$ of butachlor showed statistically significant post hatching survival with p<0.1. Abnormalities of larva were 2.1, 2.3 and 10% at 0.025, 0.05 and $0.1\;mg\;L^{-1}$ of concentration, respectively. They showed abnormal vertebral axis, craniofacial alteration and retarded yolk-sac resorption. The total length and weight were decreased depending on butachlor concentration the end of test. Weight of larva was showed more sensitive toxic indicator than total length. The toxicological responses of O. latipes to butachlor expressed as LOEC(lowest observed effect concentration), NOEC(no observed effect concentration) and MATC(maximum acceptable toxicant concentration) values were 0.025, 0.013 and $0.018\;mg\;L^{-1}$, respectively.

• Korean Journal of Ichthyology
• /
• v.4 no.1
• /
• pp.1-13
• /
• 1992

The gobiid fish, Luciogobius guttalus Gill has an anguilliform with some blackish and reddish brown color in life. It grows up to 90mm in total length. The specimens have been collected from several localities in the southern parts of Korea and Hokkaido, Japan. During the ebb tide, the fish was found in high level of intertidal zone exposed to the air among pebbles in the hollows and slopes of rocks. There are also some other small gobiid fishes comprising 3 species of relative gobies and 1 species of blennioid fish. A total of 5 egg masses were collected from the coast of Haeundae in April to May 1990. Each egg mass was deposited in one layer on the underside of a stone embedded in pebbles and guarded by the male parent. The eggs are club-shaped ranging from 2.71 to 2.80mm in long axis and from 0.65 to 0.74mm in short axis. The eggs were hatched in 98 hours after incubatied at the temperature varying from 19.5 to $25.5^{\circ}C$The newly hatched larvae were from 3.85 to 4.00mm in total length with 35~36 myomeres. In eleven days after hatching, total length reached 5.50mm. The part of the fin-fold of the future dorsal and anal fins became high. In sixteen days after hatching, the lavae averaged 6.20mm in total length and the caudal notochord flex at $45^{\circ}$. The larvae reached the juvenile stage in 48~50 days after hatching and attained 12.80~14.00mm in total length, and all fin-rays was formed. Ossification of the cranium took place at 5.50mm of mean total length in parasphenoid and basioccipital. Ossification of the visceral skeleton occurred in areas where active movements of bones are required, notalbly in the parts of feeding and respiration. Vertebrae began to develop from the anterior end to ossify posteriorly. Neural and haemal spines of vertebrae ossified always prior to the corresponding centra. When larvae reached to about 6.60mm in mean total length (17~18 days after hatching), jaw bones were more repidly ossified than vertebrae and cranium. Ossification of all bones nearly completed when the larvae reached to 13.40mm in mean total length (47~50 days after hatching).

• Tuberculosis and Respiratory Diseases
• /
• v.56 no.5
• /
• pp.505-513
• /
• 2004

Background : In lung cancer patients, the presence of metastatic neck nodes is a crucial indicator of inoperabilty. So thorough physical examination of neck is always mandatory, but sometimes those are hardly palpable even by the skillful hand. Ultrasonography is a useful diagnostic method in detection of small impalpable lymph nodes and in guidance of fine needle aspiration biopsy. In this study we evaluated the clinical usefulness of ultrasonography(USG) and ultrasound-guided fine needle aspiration cytology(US-FNA) in lung cancer patients without palpable neck nodes. Methods and Materials : From Sep 2002 to Sep 2003, 36 non-small cell lung cancer patients (20 adenocarcinoma, 16 squamous cell cancer) and 10 small cell lung cancer patients without palpable neck nodes on physical examiation were enrolled. patients who had contralateral mediastinal nodal enlargement(>1cm) on chest CT were excluded. After the routine check of USG on the neck, US-FNA was done in cases with enlarged neck nodes (${\geq}5mm$ in the short axis). The presence of enlarged lymph node on USG, and of malignant cells on cytology were evaluated by the histological type and the patients' clinical stage of lung cancer. Results : Among 36 non-small lung cell cancer patients, 14 (38.8%) had enlarged neck nodes on USG, and 5 of 10 small cell lung carcinoma patients. The mean diameter of the neck nodes was 9.8 mm (range, 7-12 mm). US-FNA of 14 non-small cell lung cancer patients revealed tumor cells in eight patients (57.1%). In 5 small cell lung cancer pateints, tumor cells were found in all cases. By the result of US-FNA, the clinical stage of 8 out of 36 (22.2%) non-small cell lung cancer patients had changed, including two cases of shift from the operable IIIa to the inoperable IIIb. In small cell lung cancer patients their clinical stage was not changed after US-FNA, but their pathological diagnosis was easily done in two cases, in whom endobronchial lesions were not found on bronchoscopy. Conclusions : USG and US-FNA of neck node seem to be safe, sensitive and cost-effective diagnostic tools in the evaluation of lung cancer patients without palpable neck nodes.

• Journal of Embryo Transfer
• /
• v.33 no.3
• /
• pp.177-183
• /
• 2018

The identification of biomarkers of a living tissues is essentially required to understand specific functions of the cells. In previous study, we reported IGFBP 3 as one of the putative biomarkers, by showing specific expression at porcine spermatogonial stem cells (SSCs) of early stage of porcine testis. In this study, we analyzed the expression of seven members of IGFBP family (IGFBPs) in SSCs and histological expression pattern of pregnancy-associated plasma protein-A (PAPP-A), which plays a role on the growth promoting enzyme by cleavage of IGFBPs in testis of 5 days old pig. RT-PCR analysis showed that IGFBP 1, 2, 3, 4, and 6 were expressed at high level specifically in porcine SSCs compared with whole testis. We performed immunohisotochemical staining of testis sections with PAPP-A and protein gene product 9.5 (PGP9.5) which are the known biomarkers for SSCs. We were not able to find co-expression of PAPP-A and PGP9.5; PAPP-A was expressed only in Sertoli cells and PGP9.5 expression was confirmed in spermatogonium. Additionally, we were able to confirm the GATA4 expression in Sertoli and Leydig cells as a regulator of Sertoli cell function was not detected PGP9.5 expressing cells, indicating indirect evidence of that cytolocalization of PAPP-A expression is limited in Sertoli cells. These results suggested that the PAPP-A expressed in Sertoli cells may play role on regulation of development and differentiation of testicular cells through the IGF axis in neonatal porcine testis.

• Restorative Dentistry and Endodontics
• /
• v.42 no.4
• /
• pp.332-341
• /
• 2017

Objectives: To determine the incidence of crack formation and propagation in apical root dentin after retreatment procedures performed using ProTaper Universal Retreatment (PTR), Mtwo-R, ProTaper Next (PTN), and Twisted File Adaptive (TFA) systems. Materials and Methods: The study consisted of 120 extracted mandibular premolars. One millimeter from the apex of each tooth was ground perpendicular to the long axis of the tooth, and the apical surface was polished. Twenty teeth served as the negative control group. One hundred teeth were prepared, obturated, and then divided into 5 retreatment groups. The retreatment procedures were performed using the following files: PTR, Mtwo-R, PTN, TFA, and hand files. After filling material removal, apical enlargement was done using apical size 0.50 mm ProTaper Universal (PTU), Mtwo, PTN, TFA, and hand files. Digital images of the apical root surfaces were recorded before preparation, after preparation, after obturation, after filling removal, and after apical enlargement using a stereomicroscope. The images were then inspected for the presence of new apical cracks and crack propagation. Data were analyzed with ${\chi}^2$ tests using SPSS 21.0 software. Results: New cracks and crack propagation occurred in all the experimental groups during the retreatment process. Nickel-titanium rotary file systems caused significantly more apical crack formation and propagation than the hand files. The PTU system caused significantly more apical cracks than the other groups after the apical enlargement stage. Conclusions: This study showed that retreatment procedures and apical enlargement after the use of retreatment files can cause crack formation and propagation in apical dentin.

• Fashion & Textile Research Journal
• /
• v.12 no.2
• /
• pp.156-161
• /
• 2010

To improve the standard of living of its citizens, local festivals is located in one axis of the new culture. These symptoms shows that there is increasing awareness of traditional culture such as Hanryu. The purpose of this study is to develope the presentative Dress of Andong International Maskdance Festival to stimulate curiosity and participate easily. 24 villages in Andong were present to represent appropriate Dress of Maskdance Festival which have been announced through the fashion show. The characteristics of the maskdance dress which presented in this study has the purpose of making the specialties of each village to tourism resources. Characteristics of the maskdance dress which designed to blend on the mask was as following. (1) Maskdance dress should shown well and must have strong durability of strenuous exercise in maskdance (2) Maskdance dress should be able to get the sympathy of the spectators. (3) Maskdance dress should be sympathetic as modern costumes. (4) Aesthetics as custumes and requirements as product must be met. (5) Acceptance of Andong region's traditional beauty is required. (6) Maskdance dress is likely to require long-term use. (7) Maskdance dress must be able to accommodate a variety of body conditions. Through customer satisfaction survey of 158 spectators and 48 members of fashion show, the relevance of masks and costumes, aesthetic and motility of costumes, commercialization potential, especially costume' motility and functional fitness of clothing sizes was highly evaluated. So maskdance dress or stage costumes as long-term development is likely to be considered. And continued research is needed.

• Korean journal of applied entomology
• /
• v.47 no.4
• /
• pp.337-343
• /
• 2008

This study was conducted to investigate the distribution pattern, ecological characteristics and life cycle of the Black Soldier Fly (Hermetia illucens, BSF). The BSF was widely distributed throughout Korea. The insect was mainly found in the vicinity of and in cattle sheds, manure sheds, living waste dump grounds, and food waste dump grounds. Developmental characteristics of the BSF are as follows: the egg was long oval shaped of 887 ${\mu}m$ in the major axis and 190 ${\mu}m$ in the minor axis; it weighed 24 ${\mu}g$. Female oviposited ca. 1,000 eggs on average; eggs hatched in 81 hours under laboratory condition ($27^{\circ}C$, 60% R.H.). The duration of the larval stage was approximately $15{\sim}20$ days. The size of the last instar larvae was 21 mm. The cuticle of the pupae gradually acquired red-brown color and the size of them was 19 mm. The pupal stage was shorter for females (16 days) than males (15 days). Adults were sized about $13{\sim}20$ mm long and black-colored. The life span of adult insects was $5{\sim}8$ days for the first generation (June${\sim}$July), $7{\sim}10$ days for the second generation (Aug.${\sim}$Sept.), and $13{\sim}18$ days for the third generation (Sept.${\sim}$Oct.). Mating started on the next day of emergence and actively occurred at the third day after emergence. Mating mostly occurred between 10:00 and 16:00 during which light intensity is highest. Egg-laying started on the third day and was most frequent from the fourth to the sixth day after emergence. Similar to mating time, females oviposited mostly between 10:00 and 16:00.

• Development and Reproduction
• /
• v.13 no.4
• /
• pp.281-289
• /
• 2009

The slime flounder Microstomus achne were caught at Geomun Island, Yosu-si, Jeollanamdo from January to March in 2006. The fertilized eggs were observed for morphological development of egg, embryo and larva. Eggs were colorless transparent, separative pelagic, absent of oil globule, and the diameter was 1.64${\pm}$0.03 mm (n=50). The eggs were hatched at 168 hours 40 minutes after fertilization in the range of $9.8\sim13.0^{\circ}C$ (mean $11.4{\pm}1.6^{\circ}C$). Total length of newly hatched larva was 4.05${\pm}$0.18 mm (n=20). The larva had developed membranous fin showing waterdrop-shaped structure, and their mouth and anus were not open. The myotomes were 14~15+33~34=47~49. The egg yolks were 1.64${\pm}$0.12 mm in major axis, and 1.23${\pm}$0.19 mm in minor axis. At 12 days after hatching, the total length was 7.32${\pm}$0.42 mm(n=20). The egg yolk was completely absorbed and transferred to post larval stage. Star-shaped melanophores and branch-shaped xanthophores in the edge of membranous fin were more densed. Chrysanthemum-shaped melanophores in the notochord were densed and formed 4~5 melanophore bands. At 90~93 days after hatching, morphological features of the larva, 19.91${\pm}$1.63 mm TL(n=20), were transferred to juvenile stage showing similar features with those of the adult fish.