• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.641-645
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• 2003

Spermatogenesis, ultrastructure, and sperm morphology of the Pacific oyster (Crassostrea gigas) were investigated with TEM and SEM. C. gigas sperm were primitive consisting of a head midpiece and tail. Sperm size (head and midpiece) was about 1.78 ${\mu}m$. Sperm morphology was similar to a sharp of a small water jar with a rough surface. Sperm had both anterior nuclear fossa (anf) and posterior nuclear fossa (pnf). Acrosome forms had a hat-like shape. The axial rod was projected in front of the acrosome. C. gigas sperm had four large mitochondria in the midpiece.

• Korean journal of applied entomology
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• v.33 no.3
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• pp.184-193
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• 1994

Ogma koesanense sp.n. has two head annuli. The first head annule is much larger than the second; blunt scales mare or less in 17-19 longitudinal l~nes and acute tail. Criconemello onnuiata. Criconema cardamoml, Ogma decalineaturn, 0. dtyum are newly recorded from Korea. Morphological characteristics of previously reported speaes, Ciiconema demani is discussed.

• The Korean Journal of Soil Zoology
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• v.7 no.1_2
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• pp.29-34
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• 2002

Hox genes are a family of regulatory gene encoding transcription factor that primarily play a crucial role during development. Several indications suggest their involvement in the control of cell growth and regenration. RT-PCR and souther blot analysis revealed that labial-like gene was increasingly expressed along a spatial gradient in the anterior region of intact worm. During head and tail regeneration, labial-like gene was expressed only in the head region of regenerating body pieces, suggesting that the gene is involved in the anteroposterior patterning in earth-worm. This result could give us information on the significance of Hox genes and the relationship between Hox genes during regeneration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.20-20
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• 2009

치아의 치석제거 및 치골절삭에 사용되는 초음파 스케일러는 일반적으로 마그넷형과 압전형으로 구분할 수 있으며, 최근에 들어 소형화, 저전력, 정밀성, 저비용 등의 장점으로 인해 압전형이 주로 사용되고 있다. 국내의 대부분의 치과에서 한 대 이상 운용되는 초음파 스케일러는 대부분 유럽 제품으로며, 국내에서는 이를 대체하기 위한 제품이 출시되고 있으나 아직까지 유럽 제품에 비해 출력강도, 정밀도 등에서 성능이 모자란 현실로 시장에서 외면 받고 있다. 본 연구에서는 앞서 언급한 압전 초음파 스케일러에 대한 체계적인 연구를 진행하여 외국에 비해 상대적으로 성능이 떨어지는 초음파 스케일러의 성능을 개선하고자 하였다. 이를 위하여 스케일러의 진동 발생부, 즉 압전 세라믹과 SUS 재질의 head, tail 부로 구성된 진동발생부의 최적구조톨 도출하기 위하여 유한요소 해석을 실시하였으며, 스케일러의 중심주파수 28kHz에서 최대 출력이 발생할 수 있는 구조를 도출하였다. 스케일러의 Head 와 Tail 부문의 두께와 직경, 길이 변화에 따른 중심주파수 및 출력 변위의 경향분석을 실시하였으며, 이상의 결과를 바탕으로 실제 스케일러를 제작하여 시뮬레이션의 유효성을 검증하였다. 이상의 과정으로 거쳐 개발된 압전 초음파 스케일러는 다양한 Tip 종류의 영향을 최소화할 수 있으며, 중심주파수는 28~30kHz 에서 뛰어난 성능을 나타내어 기종 유럽제품의 성능을 앞지르는 특성을 확보할 수 있었다.

• Applied Microscopy
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• v.32 no.4
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• pp.303-310
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• 2002

Spermatogenesis and sperm ultrastructure are investigated by means of light and transmission electron microscopy in the equilateral venus, Gomphina veneriformis which is dominant bivalve in the east coast of Korea. In the active spermatogenic season, testis consists of numerous spermatogenic follicles which is contains germ cells in the different developmental stage. The spermatogonia attached to spermatogenic follicle wall and has a large nucleus with electron-dense nucleolus. The spermatocytes are characterized by appearance of synaptonemal complex and well-developed Golgi complex. Nucleus of spermatid consists of numerous heterogeneous granules with high electron density. Karyoplasmic condensation, acrosome and flagellum formations are observed during spermiogenesis. Testicular matured sperms of sperm bundle consists of head, midpiece and tail. The head is about $8.5{\mu}m$ long and comprises a long nucleus and a bullet-like acrosome ($8.5{\mu}m$ in length). Acrosomal rod of microfilaments is observed in the lumen between nucleus and acrosome. The midpiece has four mitochondria. And tail has the typical '9+2' microtubule system.

• Korean Journal of Veterinary Research
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• v.29 no.3
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• pp.215-222
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• 1989

In order to investigate the morphological characteristics of epididymal duct of the squirrel, the histological and histochemical studies were carried out. The results obtained were summarized as follows: The epididymal duct can be divided into 9 segments by histological and histochemical features. Segments 1 to 5 were located in the head, segments 6 and 7 in the body, and segments 8 and 9 in the tail of the epididymis. The apical cells were numerous in the segment 1. Clear cells which has a compact, deeply staining nucleus and a characteristically clear cytoplasm were scattered in the epithelium throughout the duct. Interepithelial clear cells which had PAS-positive granules tended to increase in number caudally. Strong PAS-positive reaction was detected at the intralumen of the segments 3,8 and 9. Acid phosphatase activity was relatively high in the basal cytoplasm of the segment 7, and then in the supranuclear region of the segments 8 and 9. Alkaline phosphatase activity was weakly positive or negative except the segments 3 and 4. ATPase activity was strong in the free surface of the epithelium in the head and the entire cytoplasm in the body and tail, a,nd SDH activity was generally weak except for the body where it was more intense.

• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.379-386
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• 2015

The solubilization of p-chlorobenzoic acid in aqueous solutions of pure cationic, nonionic, amphoteric, and their mixed surfactant systems have been measured by the UV-Vis spectrophotometric method. The effects of hydrophobic tail-group with different chain length and the hydrophilic head-group on the solubilization of p-chlorobenzoic acid have been studied and also thermodynamic parameters have been calculated from the dependence of K_s values on the temperature. The results show that the values of ΔG^o for the solubilization by all surfactant systems are negative and the values of ΔH^o and ΔS^o are all positive.

• Advances in pediatric surgery
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• v.12 no.2
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• pp.221-231
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• 2006

Solid pseudopapillary tumor (SPT) of the pancreas occurs most frequently in the second or third decades of life, and is prevalent in females. Unlike other pancreatic malignancy, SPT usually has a low malignancy potential. This study reviews our clinical experience and surgical treatment of pancreatic SPT. Admission records and follow-up data were analyzed retrospectively for the period between January 1996 and January 2003. Five patients with a pancreatic mass were operated upon and SPT was confirmed by pathology in each case. The male to female ratio was 1: 4. The median age was 13.8 years. Findings were vague upper abdominal pain (n=5, 100 %) and an abdominal palpable mass (n=3, 60 %). The median tumor diameter was 6.8cm and the locations were 2 in the pancreatic head (40 %) and 3 in the pancreatic tail (60 %). Extra-pancreatic invasion or distant metastasis was not found at the initial operation in all five cases. A pyloruspreserving pancreaticoduodenectomy (n=1) and a mass enucleation (n=1) were performed in two patients of pancreatic head tumors. For three cases of tumors in pancreatic tail, distal pancreatectomy (n=2) and combined distal pancreatectomy and splenectomy (n=1) were performed. The median follow-up period was 60 months(12-117month). During the follow-up period, there was no local recurrence, nor distant metastasis. Postoperative adjuvant chemotherapy or radiotherapy was not carried out. All five children were alive during the follow up period without any evidence of disease relapse. SPT of the pancreas in childhood has good prognosis and surgical resection of the tumor is usually curative.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1598-1606
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• 1996

In order to achieve high accuracy of off-line character recognition(OCR) systems, the recognized text must be processed through a post-processing stage using contextual information. In this paper, we reclassify Korean word classes in terms of OCR word correction. And we collect combinations of Korean particles(approximately 900) linguistic verbal from(around 800). We aggregate 9 Korean irregular verbal phrases defined from a Korean linguistic point of view. Using these Korean word information and a Head-tail method, we can correct misrecognized words. A Korean character recognizer demonstrates 93.7% correct character recognition without a post-processing stage. The entire recognition rate of our system with a post-processing stage exceeds 97% correct character recognition.

• Korean Journal of Ichthyology
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• v.25 no.4
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• pp.239-243
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• 2013

Two specimens of the syngnathid Syngnathoides biaculeatus were collected from the coastal waters of Geoje Ialand and Tongyeong, Korea, represent first record of the species and the genus from Korea. This species is characterized by the following combination of characters: caudal fin absent; opercle without keel; superior and inferior trunk ridges continuous with their respective tail ridges; lateral trunk ridge deflected dorsal behind anal ring. Tail shorter than head and body hexagonal in its subdorsal part, posterior quadrangular, rapidly tapering, without caudal fin, prehensile. Head essentially in line with longitudinal axis of body or bent very little. New Korean names are proposed, "Jal-pi-sil-go-gi-sok" for the genus Syngnathoides, and "Jal-pi-sil-go-gi" for S. biaculeatus.