• 대한소아치과학회지
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• 제47권4호
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• pp.463-468
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• 2020

유표피낭종은 구강 내에서 드물게 보이는 양성병소이며 선천적 혹은 후천적으로 발생할 수 있다. 이 병소는 대개 느리게 자라는 낭종으로, 저작이나 발음을 방해 할 정도로 크기가 커지거나 2차 감염이 발생하기 전 까지는 주로 무증상을 보인다. 따라서 진단이 지연되는 경우가 많으며, 신생아나 영유아에서 진단되는 경우는 매우 드문 병소이다. 유표피낭종은 대부분 구강저에서 발생하며 상순에서의 발생은 드물다. 이 증례에서는 29개월 환아의 상순 내측 점막에서 촉진되는 종물을 구강 내 접근법을 이용하여 외과적으로 적출하고, 조직 병리학적으로 유표피 낭종으로 진단하였기에 보고하는 바이다.

• Animal cells and systems
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• 제2권4호
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• pp.513-520
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• 1998

Though the wandering spiders do not produce webs for prey-catching, they have silk producing apparatus. Among the four kinds of silk glands in the wolf spider, Pardosa astrigera, the ampullate one is the most predominant gland in both sexes, and is composed of three functional parts; excretory duct, storage ampulla and convoluted tail regions. The duct is basically composed of three superposed types of layers which are inner cuticles, monolayered epithelial cells and peripheral connective cells. The electron lucent subcuticles which have the functions of water removal and orientation of silk fibers during polymerization are well developed at the anterior region near the spinneret. Whereas the endocuticles which contain two types of banding patterns at the cross section are developed at the rest of the duct region. The secretory silks are synthesized within the glandular epithelial cells of the tail as secretory granules, and then released to the inner cavity of the storage ampulla by the mechanism of apocrine secretion. Most of these secretory vesicles are originated from the rough endoplasmic reticula of the glandular epithelial cells, whereas no Golgi complexes are found in any of the cells which have been examined.

• Journal of Oral Medicine and Pain
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• 제5권1호
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• pp.5-10
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• 1980

Numerous investigators have pointed out that the force of the tongue against the teeth within the dental arches is normally compensated for by the action of the musculature of the cheeks and lips, and that the tongue at rest occupies a large part of the oral cavity. The purpose of this study was to estimate the maximum areas of the tongue movement by measuring the inner area of the dental arches of both the maxilla and the mandible. This study was based on the study models of 30 children and 128 adults who had clinically good occlusion. There were 15 male and 15 female children whose ages ranged from four years to seven years and 82 male and 46 female adults whose ages ranged from fifteen years to fifty four years. The obtained results were as follows : 1. The mean of the maximum areas within the primary dental arches of both the maxilla and the mandible were $7.06\pm0.8\textrm{cm}^2, 5.49\pm0.77\textrm{cm}^2$ in male children and $6.82\pm0.98\textrm{cm}^2, 5.28\pm0.80\textrm{cm}^2$ in female children respectively. 2. The mean of the maximum areas within the permanent dental arches of both the maxilla and mandible were $17.01\pm2.38\textrm{cm}^2, 13.57\pm1.57\textrm{cm}^2$ in male and $16.75\pm2.08\textrm{cm}^2, 13.36\pm1.01\textrm{cm}^2$ in female respectively.

• 한국통신학회논문지
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• 제12권2호
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• pp.133-138
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• 1987

본 논문에서는 Re-enterant 공동 공진기의 내부 도체봉 길이 변화에 따른 공진 주파수의 가변특성을 실험정그로 고찰하였다. 실험시 제작된 공진기는 동축 케이블과 원형 도파관을 경합한 형태로서 동축 케이블의 내부 도체봉의 길이를 축방향으로 면화시킬 수 있도록 하여, 내부 도체봉의 임의의 길이에 대한 Tmonq 모드의 공진 주파수를 측정하였다. 경과의 타당성을 입증하기 위해서 실험 경과와 여러 사람들의 이론치를 비교하였다. 본 실험의 결과는 파장계, 공진기?l 증폭기의 공진 회로의 설계및 제작에 활용할 수 있으며 마이크로 웨이브 집적회로(MIC, Microwave Integrated Circuits)나 여과기에 사용되는 유전체 공진기의 공진 주파수를 가변시키는데도 사용할 수 있다.

• 마이크로전자및패키징학회지
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• 제12권3호
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• pp.267-274
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• 2005

This paper presents the fabrication of surface acoustic wave (SAW)-based pressure sensor for long-term stable mechanical compression force measurement. SAW pressure sensor has many attractive features for practical pressure measurement: no battery requirement, wireless pressure detection especially at hazardous environments, and easy other functionality integrations such as temperature, humidity, and RFID. A $41^{\circ}$ YX $LiNbO_3$ piezoelectric substrate was used because of its high SAW propagation velocity and large values of electromechanical coupling factors $K^2$. A silicon substrate with $\~200{\mu}m$ deep cavity was bonded to the diaphragm with epoxy, in which gold was covered all over the inner cavity in order to confine electromagnetic energy inside the sensor, and provide good isolation of the device from its environment. The reflection coefficient $S_{11}$ was measured using network analyzer. High S/N ratio, sharp reflected peaks, and clear separation between the peaks were observed. As a mechanical compression force was applied to the diaphragm from top with extremely sharp object, the diaphragm was bended, resulting in the phase shifts of the reflected peaks. The phase shifts were modulated depending on the amount of applied mechanical compression force. The measured $S_{11}$ results showed a good agreement with simulated results obtained from equivalent admittance circuit modeling.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.269-277
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• 2009

The current paper focuses on the analysis of transient cavitating flow in pressurised polyethylene pipes, which are characterized by viscoelastic rheological behaviour. A hydraulic transient solver that describes fluid transients in plastic pipes has been developed. This solver incorporates the description of dynamic effects related to the energy dissipation (unsteady friction), the rheological mechanical behaviour of the viscoelastic pipe and the cavitating pipe flow. The Discrete Vapour Cavity Model (DVCM) and the Discrete Gas Cavity Model (DGCM) have been used to describe transient cavitating flow. Such models assume that discrete air cavities are formed in fixed sections of the pipeline and consider a constant wave speed in pipe reaches between these cavities. The cavity dimension (and pressure) is allowed to grow and collapse according to the mass conservation principle. An extensive experimental programme has been carried out in an experimental set-up composed of high-density polyethylene (HDPE) pipes, assembled at Instituto Superior T$\acute{e}$cnico of Lisbon, Portugal. The experimental facility is composed of a single pipeline with a total length of 203 m and inner diameter of 44 mm. The creep function of HDPE pipes was determined by using an inverse model based on transient pressure data collected during experimental runs without cavitating flow. Transient tests were carried out by the fast closure of the ball valves located at downstream end of the pipeline for the non-cavitating flow and at upstream for the cavitating flow. Once the rheological behaviour of HDPE pipes were known, computational simulations have been run in order to describe the hydraulic behaviour of the system for the cavitating pipe flow. The calibrated transient solver is capable of accurately describing the attenuation, dispersion and shape of observed transient pressures. The effects related to the viscoelasticity of HDPE pipes and to the occurrence of vapour pressures during the transient event are discussed.

• 비파괴검사학회지
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• 제15권1호
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• pp.299-309
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• 1995

IR CAT Scan 개발을 위한 기하학적 역 열전도 문제의 해를 경계요소법 및 정규화 과정을 사용하여 구하였다. 이 문제에서는 잉여기술된 온도조건이 적외선 스캐닝에 의해 표면에 주어지며, 이 조건은 다른 조건과 함께 미지경계의 위치를 계산하는데 사용되었다. 문제의 해를 구하기 위해 보조문제가 도입되었고, 이 보조문제의 영역에 대한 가상적인 내부경계를 정의함으로써 공동(cavity)이 영역 내부에 위치하게 되며, 포텐셜 문제의 해를 구하여 그 위치를 결정하였다 이 문제의 해를 구하기 위해 경계요소법이 정규화과정과 함께 사용되었으며, 수치해석을 통하여 역 해법에 대한 정규화 효과를 분석하였다.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.201-216
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• 1990

A variety of surface pre-treatments have been advocated to prepare the dentin prior to placement of a bonding agent. The purpose of this study was to evaluate the effect of various dentin conditioners upon the degree of resin impregnation to the dentinal tubules and the shear bond strength of a new dentinal bonding agent (Scotchbond 2) used in conjunction with a visible light cured composite (Silux). The healthy eighty human molars extracted due to periodontal or orthodontic reasons were used and randomly divided into five groups. All the grinded dentin surfaces were conditioned with 3% $H_2O_2$, Cavity Cleanser (Columbus/Bayer), Dentin Conditioner (GC Inter. Corp.), Scotchprep (3M Co.) according to the manufacturer's directions. The specimens were then demineralized in 10% HCl for 20 sec. and 24 hrs. in order to observe the resin tags in Hitachi X-450 scanning electron microscope at 25KV. Also, shear strengths were obtained using an Instron Testing Machine with a cross head speed of 1 mm/min. The following results were obtained ; 1. In group treating with Dentin Conditioner and Scotchprep, the resin strings were formed on most of the surfaces and penetrated more than $50{\mu}m$ into the tubules. 2. The inner surface of resin treated with Cavity Cleanser, indicating the resin strings formed partly and penetrated about in depth of $30{\mu}m$. 3. In control and experimental group treated with 3% $H_2O_2$, the resin tags were not formed, if any, penetrated shortly. 4. Shear bond strengths in groups treating with Dentin Conditioner and Scotchprep were statistically significant increase than with 3% $H_2O_2$. (P<0.01). 5. The Scotchprep treatment group was significantly higher in shear strength than groups treated with no conditioning and Cavity Cleanser.(P<0.01) 6. Shear bond strengths evaluated were gradually increase in proportion to the tag length of resin impregnation.

• 한국발생생물학회지:발생과생식
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• 제10권3호
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• pp.193-196
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• 2006

이 연구는 태생경골어인 쏨뱅이의 번식생태학적 기초자료를 제공하고자 체내 자어와 출산 후의 시원생식세포의 출현, 원시 생식소와 난소 분화과정을 조직학적으로 조사하였다. 약 $10\;{\mu}m$의 시원생식 세포는 체내 자어의 초기 소화관과 중심신관 사이 복막에 위치하였다. 출산 후 31일째부터 생식원세포가 생식원기에 도달하였으며, 체세포들이 분열 증식하여 원시생식소를 형성하였고, 출산 후 49일째에 난소강이 형성되기 시작하였으며, 출산 후 60일째에 생식원기의 양쪽 끝에서부터 난소강 형성이 관찰되었다. 출산 후 79일째에는 난소강 안쪽을 따라 생식세포들이 분열 증식하기 시작하였다.

• 한국수산과학회지
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• 제36권3호
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• pp.270-275
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• 2003

Histochemical characteristic and ultrastructure of the mantle of the granular ark, Tegillarca granosa are described using light and electron microscopy. The mantle of the clam is composed of outer epidermis, connective tissue and inner epidermis. The simple epidermis consists of supporting cells, ciliated cells of the two types and secretory cells of three types. Connective tissue is composed of matrix, collagen fibers, muscular fibers and hemolymph sinus. The columnar supporting cell is covered with microvilli on the free surface. Ciliated cells are distributed in the inner epidermis with numerous cilia, microvilli and tubular mitochondria. Secretory cells could be classified into three types (A, B and C) with morphological features of the secretory granules. Type A secretory cells contains secretory granules with fibrous materials of high electron density Type B secretory cells are more abundant than the other cells, and contains secretory granules of membrane-bounded and high electron density. Secretory granules of the type C cells are divided into fibrous core layer and homogeneous peripheral layer. Type B secretory cells are abundant in the both epidermis of marginal mantle, while large number of type A and C secretory cells are evident in the outer epidermis of the central and umbonal mantle. This result showed that the outer and the inner epidermis of the mantle are related with shell formation and cleaning of the mantle cavity, respectively.