• International Journal of Oral Biology
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• 제37권1호
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• pp.9-16
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• 2012

The aim of this study was to evaluate surface characteristics and biological properties of the dentin -derived hydroxyapatite (HA) coating on titanium substrate. Dentinderived HA was obtained from extracted human teeth using a calcination method at $850^{\circ}C$. The commercially pure titanium (cp-Ti, ASTM Grade II) was used as a metallic substrate and a radio frequency magnetron sputtering method was employed as a coating method. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were utilized to investigate the coating aspects and composition. Atomic forced microscopy (AFM) and a surface profiler were used to assess the surface morphology and roughness. Corrosion tests were performed in phosphate-buffered saline at a $36.5{\pm}1^{\circ}C$ in order to determine the corrosion behavior of the uncoated and coated specimens. The biocompatibility of dentin-derived HA coated specimens with fetal rat calvarial cells and human gingival fibroblasts was assessed by SEM and cell proliferation analysis. The results showed that the dentin-derived HA coatings appeared to cover thinly and homogeneously the surfaces without changing of the titanium substrate. The EDX analysis of this the coating surface indicated the presence of Ca and P elements. The mean surface roughness of cp-Ti and dentin-derived coating specimens was $0.27{\mu}m$ and, $1.7{\mu}m$, respectively. Corrosion tests indicated a stable passive film of the dentin-derived HA coating specimens. SEM observations of fetal rat calvarial cells and human fibroblast cells on coated surfaces showed that the cells proliferated and developed a network of dense interconnections. The cells on all specimens proliferated actively within the culture period, showing good cell viability. At day 1 and 3, dentin-derived coating specimens showed 89% and 93% cell viability, respectively, when normalized to cp-Ti specimens. These results suggest that dentin-derived HA coating using the RF magnetron sputtering method has good surface characteristics and biocompatibility.

• 한국초전도ㆍ저온공학회논문지
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• 제6권3호
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• pp.16-20
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• 2004

YB $a_2$C $u_3$$O_{7-x}$ (YBCO) films were deposited on (100) SrTi $O_3$ single crystal substrates by a metal organic chemical vapor deposition (MOCVD) system of hot-wall type using single liquid source. Under the condition of the mole ratio of Y(tmhd)$_3$:Ba(tmhd)$_2$:Cu(tmhd)$_2$= 1:2.1:2.9. the deposition pressure of 10 Torr. the MO source line speed of 15 cm/min. the Ar/ $O_2$ flow rate of 800/800 sccm. YBCO films were prepared at the deposition temperatures of 780∼89$0^{\circ}C$. In case of the YBCO films with 2.2 ${\mu}{\textrm}{m}$ thickness deposited for 6 minutes at 86$0^{\circ}C$. XRD pattern showed complete c-axis growth and SEM morphology showed dense and crack-free surface. The atomic ratios of Ba/Y and Cu/Ba in the film were 1.92 and 1.56. respectively. The deposition rate of the film was as high as 0.37 ${\mu}{\textrm}{m}$/min. The critical temperature ( $T_{c.zero}$) of the film was 87K. The critical current of the film was 104 A/cm-width. and the critical current density was 0.47 MA/$\textrm{cm}^2$. For the thinner film of 1.3 ${\mu}{\textrm}{m}$ thickness. the critical current density of 0.62 MA/$\textrm{cm}^2$ was obtained.d.

• 열처리공학회지
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• 제22권5호
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• pp.290-297
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• 2009

In case of using Asymmetric Bipolar Pulsed DC (ABPD) power generator, thin film is efficiently deposited as ions are getting higher energy by suppressing target poisoning and electric arc. In this article, the mechanical properties of CNx thin films deposited on the STS 316L were compared with DC and ABPD power generators. The CNx thin films deposited with ABPD clearly improved wear resistance by higher ratio of sp3CN as compared with DC. Nb interlayer affected to increase the value of 10N of adhesion between CNx thin films and substrate. But, CNx thin films deposited with ABPD couldn't endure to wear load and decreased wear resistance as the films were too thinner than substrate. Nevertheless the higher substrate bias energy applied to perform the dense films, it wasn't shown benefits about the wear properties from DC sputtering. But, in case of using ABPD sputtering, the wear resistance was largely improved without changing morphology despite of thin films.

• Parasites, Hosts and Diseases
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• 제31권3호
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• pp.183-192
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• 1993

Fibricola seoulensis의 고환내 생식세포 및 정자의 미세구조를 관찰하고자 하였다. 실험감염 흰쥐로 부터 회수한 충체를 고정, 탈수 침투 포매, 중합 등의 통상적인 시료제작 과정을 거친 후 JEM 1200EX-ll(JEOL, Japan) 투과전자현미경으로 관찰하였다. 정원세포는 주로 고환의 내벽에서 관찰되었으며 비교적 큰 핵과 상대적으로 적은 세포질을 가지고 있었다. 정모세포는 핵의 량이 세포질 보다 조금 많았고 난형 또는 타원형의 핵을 가지고 있었으며 비교적 염색질의 량이 적었다. 초기의 정자세포는 핵에 비하여 세포질의 량이 훨씬 많았고 핵주위를 사립체들이 둘러싸고 있었다. 발육이 진전된 정자세포에는 끈 모양의 염색질이 나타났고. 세포질에서는 결정체구조가 나타났으며 핵 근처에서는 2개의 축사 뿌리와 중심체가 관찰되었다. 고환과 저정낭에서 무수히 많은 정자의 단면이 관찰되었다 횡단면을 형태학적 특징과 구성요소를 토대로 분류·조합해 본 바 6가지 형으로 대별되었고 정자 부위별 횡단면의 특징적인 형태를 관찰할 수 있었다. F. seoulensis의 정자는 2편모성이었으며 축사는 9쌍의 미세소관과 1개의 core complex로 이루어져서 전형적인 9 + 1형 구조이었다.

• 한국해양공학회지
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• 제25권4호
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• pp.66-71
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• 2011

The flexural strength of $MoSi_2$ based composites reinforced with Nb sheets has been investigated, based on the detailed examination of their microstructure and fractured surface. Both sintered density and porosity of Nb/$MoSi_2$ composites were also examined. Nb/$MoSi_2$ composites were fabricated by different conditions such as temperature, applied pressure and its holding time, using a hot-press device. The volume fraction of Nb sheet in this composite system was fixed as 10%. The characterization of Nb/$MoSi_2$ composites were investigated by means of optical microscopy, scanning electron microscope and three point bending test. Nb/$MoSi_2$ composites represented a dense morphology at the interfacial region, accompanying the creation of two types of reaction layer by the chemical reaction of Nb and $MoSi_2$. Nb/$MoSi_2$ composites possessed an excellent density at the fabricating temperature of $1350^{\circ}C$, corresponded to about 95% of theoretical density. The flexural strength of Nb/$MoSi_2$ romposites were greatly affected by the pressure holding time at the same fabricating temperature, owing to the large suppression of porosity in the microstructure. Especially, Nb/$MoSi_2$ composites represented a good flexural strength of about 310 MPa at the fabricating condition of $1350^{\circ}C$, 30MPa and 60min, accompanying the pseudo-ductile fracture behavior by the deformation of Nb sheet and the interfacial delamination.

• 한국환경과학회지
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• 제23권8호
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• pp.1463-1468
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• 2014

An exotic parasitic wasp Anisopteromalus apiovorus of Pteromalidae was newly recorded in Korea. Specimens of this species have been collected in Gimhae of Korea since 2012. External morphology of this species was described in detail and diagnostic differences of this species from the related species and the host insect were also given. The funicle segments of female antennae are 1.2 to 1.5 times longer than those of Anisopteromalus calandrae, an sister species. Body color is gold-glossy black and with dense creamy-white hairs on the surface. This exotic species has been originated from the African continent including Democratic Republic of Congo and Cote d'Ivoire, and then intruded into other countries, for instance, Korea. This is the first distribution record of this species except the country of origin after original description as a new species. Although little is known about the life history or ecology of this species, we found that a new host of this small parasitic wasp is Lasioderma serricorne of coleoptera through present study. And this species possibly be a new agent of biological control for economic pests. It was presumed that the invasion of Anisopteromalus apiovorus into Korea was prior to November of 2012.

• 대한세포병리학회지
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• 제16권1호
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• pp.52-56
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• 2005

Fine-needle aspiration cytology (FNAC) has been used extensively in the diagnosis of metastatic malignancies. However, metastatic soft tissue sarcomas are often overlooked, primarily due to the low frequency with/ which they occur. Here, we report a rare case of metastatic rhabdomyosarcoma in both cervical lymph nodes, which was detected by FNAC. A 45-year-old woman presented with anosmia, postnasal drip, and sneezing, symptoms which had persisted for 1 month. The patient was found to have a tumorous lesion at the upper portion of the mid-turbinate, with multiple enlarged cervical lymph nodes, and this lesion was examined closely at our facility. FNA cytology smears obtained from both cervical lymph nodes revealed a high degree of cellularity, and displayed cohesive clusters with gland-like spaces, as well as single isolated cells with abundant karyorrhectic debris. The tumor cells exhibited round to oval nuclei containing fine chromatin, occasional small nucleoli, and scanty cytoplasm, or a total lack of cytoplasm. Some of the tumor cells were arranged in multinucleated forms and abundant dense eosinophilic cytoplasms, reminiscent of a rhabdomyoblast. The histological findings on the lymph nodes revealed an outstanding sinusoidal infiltration and a prominent alveolar growth pattern, interspersed with occasional typical rhabdomyoblasts. The immunohistochemical results [desmin (+), myoglobin (+), myogenin (+), pan CK (-), synaptophysin (-), neuron specific enolase (-)] supported a confirmative diagnosis of alveolar rhabdomyosarcoma. Alveolar rhabdomyosarcoma is a representative sarcoma, which typically manifests with nodal metastasis and carcinoma-like clustering. The cytopathologist should remain alert upon encountering unusual morphology, so that the possibility of this condition, although somewhat remote, should not be dismissed or overlooked.

• Applied Microscopy
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• 제31권4호
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• pp.325-331
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• 2001

돌가자미의 피부 상피층을 다층상피층으로 지지세포, 선세포 그리고 과립세포들로 구성된다. 상피층은 지지세포의 형태와 구조에 따라 표면층, 중간층 및 기저층으로 구분 할 수 있었다. 지지세포들의 세포질은 피질부와 수질부로 나누어지는데 피질부에는 미세섬유의 발달이 뚜렷하다. 점액세포들은 단세포선으로 상피의 표면층과 중간층에서 관찰된다. 점액세포의 점액물질은 중성이며, carboxylated mucosubstance의 당단백 질로 확인되었다. 곤봉상세포는 세포질에 잘 발달된 활면소포체와 골지체를 가진다. 과립세포는 주로 중간층과 기저층에 존재하고, 세포질은 막을 가진 전자밀도가 높은 과립들이 차지한다. 색소세포는 세포질에 존재하는 함유물의 전자밀도에 따라 세 종류로 구분할 수 있었으며, 색소세포 근처에서 신경종말을 관찰할 수 있었다.

• Current Photovoltaic Research
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• 제8권1호
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• pp.27-32
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• 2020

CuS thin films were deposited on glass substrates at room temperature by RF magnetron sputtering. The structural and optical properties of CuS thin films grown by varying RF-power from 40 W to 100 W were studied. From the XRD analysis, we confirmed hexagonal crystal structures grown in the preferred orientation of the (110) plane in all CuS thin films, and the intensity of the main diffraction peak increased in proportion to the increase of RF-power. In the case of CuS thin film deposited at 40W, small-sized particles formed a thin and dense surface morphology with narrow pore spacing, relatively. As the power increased, the grain size and grain boundary spacing increased sequentially. The peaks for the binding energy of Cu 2p_3/2 and Cu 2p_1/2 were determined at 932.1 eV and 952.0 eV, respectively. The difference in binding energy for the Cu²⁺ states was the same at 19.9 eV regardless of process parameters. The transmittance and band gap energy in the visible region tended to decrease with increasing sputtering powers.

• 한국재료학회지
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• 제23권8호
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• pp.469-475
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• 2013

Al-doped ZnO(AZO) thin films were synthesized using atomid layer deposition(ALD), which acurately controlled the uniform film thickness of the AZO thin films. To investigate the electrical and optical properites of the AZO thin films, AZO films using ALD was controlled to be three different thicknesses (50 nm, 100 nm, and 150 nm). The structural, chemical, electrical, and optical properties of the AZO thin films were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, field-emssion scanning electron microscopy, atomic force microscopy, Hall measurement system, and UV-Vis spectrophotometry. As the thickness of the AZO thin films increased, the crystallinity of the AZO thin films gradually increased, and the surface morphology of the AZO thin films were transformed from a porous structure to a dense structure. The average surface roughnesses of the samples using atomic force microscopy were ~3.01 nm, ~2.89 nm, and ~2.44 nm, respectively. As the thickness of the AZO filmsincreased, the surface roughness decreased gradually. These results affect the electrical and optical properties of AZO thin films. Therefore, the thickest AZO thin films with 150 nm exhibited excellent resistivity (${\sim}7.00{\times}10^{-4}{\Omega}{\cdot}cm$), high transmittance (~83.2 %), and the best FOM ($5.71{\times}10^{-3}{\Omega}^{-1}$). AZO thin films fabricated using ALD may be used as a promising cadidate of TCO materials for optoelectronic applications.