• 치과방사선
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• 제25권1호
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• pp.71-87
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• 1995

The purpose of this study was to investigate the early irradiation changes on the ultrastructure of the capillary endothelial cell in the rat submandibular glands. For the study, 110 Sprague-Dawley strain male rats were singly irradiated to their neck regions with the doses of 2Gy, 5Gy, and 10Gy by 6MV X -irradiation, and sacrificed on the 3 hours, 6 hours, 12 hours, 1 day, 3 days, 7 days, and 14 days after irradiation. The authors observed the histologic and ultrastructural changes of the capillary endothelial cell using the light and electron microscopes. The results were as follows: I. In the light microscopic examination, the capillary dilation was observed on the 6 hours group and the capillary density was slightly increased on the 12 hours group after 2Gy and 5Gy irradiation. And luminal size and capillary density were decreased on the 3 days and the 7 days groups after irradiation, after then, they were recovered. But capillary density was still decreased on the 14 days group after 10Gy irradiation. 2. In the transmission electron microscopic examination, the mild proliferation of cytoplasmic process of the endothelial cell and reduction in luminal size were observed on the 3 hours group after irradiation. After then, endothelial swelling, marked proliferation of cytoplasmic process, thickened basal lamina, and numerous pinocytotic vesicles were observed after the 1 day group after irradiation. Thickened basal lamina and numerous pinocytotic vesicles were still observed until the 7 days group after irradiation. These changes were recovered to normal on the 14 days group after 2Gy and 5Gy irradiation, but not after 10Gy irradiation. 3. In the scanning electron microscopic examination, the dilation of conduits and constriction, and meandering were observed on the 1 day group after 10Gy irradiation. These changes were observed with increased coarseness of the surface of the vascular resin casting on the 3 days group after irradiation. 4. From the above results, endothelial swelling, proliferation of cytoplasmic process, and thickening of the basal lamina appeared before the 6 hours group after irradiation. And these changes may also induce the increase of the capillary number and luminal size, after then, capillary permeability was increased via the increase of the number of pinocytotic vesicles. The changes were observed earlier and more apparent with the increase of the irradiation doses under the dose of 10Gy irradiation.

• 한국재료학회지
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• 제19권10호
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• pp.555-561
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• 2009

Expanded graphite (EG) is synthesized by chemical intercalation of natural graphite (NG) and rapid expansion at high temperature, with titanium n-butoxide (TNB) used as titanium source by a sol-gel method to prepare EG-TiO$_2$ composite. The performances of the prepared EG-TiO$_2$ composite are characterized by BET surface area measurement, scanning electron microscopy (SEM), X-ray diffraction patterns (XRD) and energy dispersive X-ray analysis (EDX). To compare the photocatalytic activities of the EG-TiO$_2$ composite, three kinds of dye solutions, methylene blue (MB), methylene orange (MO) and rhodamine B (RhB), and two kinds of light source, UV light and visible light (VL), are used. Comparing the results, it can be clearly seen that the degradation of all of the dye solutions under irradiation by UV light is much better than that under irradiation by visible light, and the decomposition of MB solution was better than that of both of MO and RhB solution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.241-241
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• 2010

Recently high and persistent spontaneous buildup of a surface potential (SP) upon vacuum deposition of tris (8-hydroxyquinolinato) aluminum (III) ($Alq_3$), which is widely used for organic light emitting devices. The removal of the giant surface potential by visible light irradiation has also been reported. In this study, we coated $Alq_3$ on the FTO substrate and raise the capacity for absorbing sun light. The $Alq_3$ which is green light emitting diode emits light at wavelengths between 500 and 550nm. If we apply one's FTO/$Alq_3$ substrate in one's DSSC, we could get higher energy conversion efficiency because the N719 dye that we used for fabricating the DSSC emits light just at near 540nm. The energy conversion efficiency of approximately 4.8 % at the condition of irradiation of AM 1.5 (100 mW/$cm^2$) simulated sunlight, and the $J_{sc}$ is 12.0 mA/$cm^2$, $V_{oc}$ is 0.71 V, FF is 0.56, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.41-44
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• 1999

Displacement current was generated in the pressure stimulus and light stimulus. Solution of azobenzene molecules (8A5H) have to character trans-to-cis. Pressure stimulus generate in the pressure and current. light stimulus generate in the displasement current. The Maxwell displacement current measuring technique has been applied for the investigation of azobenzene organic thin films under alternating photoirradiation with ultraviolet(360nm) and visible (450nm) light. The displacement current was generated due to the trans-to-cis photoisomerization by irradiation with ultraviolet light(λ$_1$=360 nm) Whereas the displacement current was generated in the opposite direction due to the cis-to-trans photoisomerization by irradiation with visible light(λ$_2$=450nm). As result, To show twice reaction certainly phase transition in pressure. A first range generated from 24$\AA$$^2$ to 29$\AA$$^2$and second range generated from 20$\AA$$^2$to 24$\AA$$^2$. Also, cetainfy stimulus apper low pressure and high pressure in photoirradiation. To see different every moment phase transition.

• 한국재료학회지
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• 제22권2호
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• pp.91-96
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• 2012

AC and ZnS modified $TiO_2$ composites (AC/ZnS/$TiO_2$) were prepared using a sol-gel method. The composite obtained was characterized by Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, scanning electron microscope (SEM) analysis, and according to the UV-vis absorption spectra (UV-vis). XRD patterns of the composites showed that the AC/ZnS/$TiO_2$ composites contain a typical single and clear anatase phase. The surface properties as observed by SEM present the characterization of the texture of the AC/ZnS/$TiO_2$ composites, showing a homogenous composition in the particles showing the micro-surface structures and morphology of the composites. The EDX spectra of the elemental identification showed the presence of C and Ti with Zn and S peaks for the AC/ZnS/$TiO_2$ composite. UV-vis patterns of the composites showed that these composites had greater photocatalytic activity under visible light irradiation. A rhodamine B (Rh.B) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of Rh.B was determined using UV/Vis spectrophotometry. An increase in the photocatalytic activity was observed. From the photocatalytic results, the excellent activity of the Y-fullerene/$TiO_2$ composites for the degradation of methylene blue under visible irradiation could be attributed to an increase in the photo-absorption effect caused by the ZnS and to the cooperative effect of the AC.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.164-164
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• 2013

Among multicomponent nanostructures, hybrid nanocatalysts consisting of metal nanoparticle-semiconductor junctions offer an interesting platform to study the role of metal-oxide interfaces and hot electron flows in heterogeneous catalysis. In this study, we report that hot carriers generated upon photon absorption significantly impact the catalytic activity of CO oxidation. We found that Pt-CdSe-Pt nanodumbbells exhibited a higher turnover frequency by a factor of two during irradiation by light with energy higher than the bandgap of CdSe, while the turnover rate on bare Pt nanoparticles didn't depend on light irradiation. We also found that Pt nanoparticles deposited on a GaN substrate under light irradiation exhibit changes in catalytic activity of CO oxidation that depends on the type of doping of the GaN. We suppose that hot electrons are generated upon the absorption of photons by the semiconducting nanorods or substrates, whereafter the hot electrons are injected into the Pt nanoparticles, resulting in the change in catalytic activity. We discuss the possible mechanism for how hot carrier flows generated during light irradiation affect the catalytic activity of CO oxidation.

• 한국식품저장유통학회지
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• 제24권3호
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• pp.381-386
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• 2017

Ergocalciferol은 vitamin D의 활성을 가지는 것으로 알려져 있다. 본 연구에서는 팽이(Flammulina velutipes), 느타리 (Pleurotus ostreatus), 애느타리(Pleurotus ostreatus), 새송이(Pleurotus eryngii), 양송이(Agaricus bisporus), 표고(Lentinula edodes), 목이(Auricularia auricula-judae) 등 7종의 버섯을 대상으로 자외선 조사에 따른 ergocalciferol(EC, 비타민 $D_2$) 함량의 증진 효과를 조사하였다. 자외선을 조사하지 않은 버섯의 ergocalciferol 함량은 극히 낮았으나 자외선 조사에 의해 ergocalciferol 함량이 크게 증가하였으며, 자외선 A, B, C 중 특히 자외선 B가 EC 함량 증진에 효과적이었다. 버섯에서 ergocalciferol의 생성은 자외선에 직접 노출되는 부위 즉 깊이 1 mm 이내의 버섯 표면에서만 일어나는 것으로 조사되었다. 따라서 세절하지 않은 생 버섯에 자외선을 조사할 경우 팽이 버섯과 같이 체적에 비해 표면적인 넓은 종류의 버섯에서 ergocalciferol 생성이 많았고, 건조 및 세절할 경우에는 EC 생성의 기질인 ergosterol의 함량이 높은 버섯에서 ergocalciferol 생성이 많았는데, 새송이, 표고, 양송이 등이 이에 속하였다.

• 한국식품과학회지
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• 제52권5호
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• pp.538-545
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• 2020

본 연구에서는 배추김치(RK)와 백김치(WK) 시료를 이용하여 72시간의 저장 기간 동안, Blue-LED 조사 효과를 확인하였다. BLED 처리에 의해 RK에서의 유산균 증식이 유의적으로 증가하였으나(p<0.05), 곰팡이 및 효모의 생육도에서는 대조구와 차이를 나타내지 않았다. 색도의 경우, BLED 처리 시 대부분 명도가 조금 높아지는 경향을 보였으며, BLED 조사에 의해 색의 변화가 일정기간 지연되는 효과를 확인할 수 있었다. BLED 처리에 의해 WK는 저장기간 동안 pH 감소가 유의적으로 지연되는 것을 관찰할 수 있었다(p<0.05). ABTS법에 의해 측정된 산화방지 활성에서는 두 종류의 김치시료액 모두 BLED처리구에서 유의적으로 높은 활성을 보였다(p<0.05). 두 김치에서 우점종으로 분리된 W. cibaria RK1와 W. cibaria WK1 유산균은 BLED에 민감하게 작용하여 모두 생육이 저해되었고, 표준 균주인 Leu. mesenteroides는 BLED 조사에 의한 생육도의 변화가 나타나지 않았다. 현재까지 BLED 조사를 이용한 유해 균주 억제 연구가 주로 이루어진 반면, 현 연구에서는 BLED조사에 의한 김치 발효상의 특성 변화와 발효미생물들의 생육도를 확인함으로써 발효 식품의 숙성 시기에 따라 적절한 LED 광원을 이용한 발효 미생물들의 생육 조절과 식품의 기능적 향상 가능성을 제시하였다.

• 대한소아치과학회지
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• 제25권1호
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• pp.76-92
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• 1998

The purpose of this study was to evaluate the possible efficacy of Nd-YAG laser as a dentin conditioner by observing the laser irradiation dentin surface under scanning electron micrograph and measuring shear bond strength of restored light-cured glass ionomer mold. Fifty intact premolars were prepared for shear bond strength tests. The teeth were randomly divided into five groups as follows; Group I. no treatment Group II. 10% poly acrylic acid, 20 sec Group III. laser treatment 2 w, 20 Hz, 2 sec Group IV. laser treatment 2 w, 20 Hz, 5 sec Group V. laser treatment 2 w, 20 Hz, 10 sec Samples of each group were restored with light-cured glass ionomer cement after dentin conditioning and then measuring the shear bond strength of each specimen were measured using universal testing machine. Additional ten premolars were prepared for SEM analysis The result from the this study can be summarized as follows. 1. Shear bond strength of polyacrylic acid-treated group (II) was significantly higher than other groups (p<0.05). 2. No statistically significant difference could be found between three laser-treated groups (III, IV, V) in shear bond strength(p>0.05) 3. According to the result of observation under SEM, Polyacrylic acid was shown to have removed the smear layer effectively and opened the dentinal tubules, whereas the laser has produced the irregular surface mainly composed of melted and fused structure. The microcracks found in laser-treated groups increased in number with irradiation time and formed the regular mesh-type in 10 sec-irradiation group. 4. The ultrastructural change of dentin surface created by laser irradiation was found to the improper for bonding of the glass ionomer restorative materials. And the lower shear bond strength of laser irradiated group might have been due to the failure to form the suit able dentin surface for the glass ionomer to penetrated into and form the proper micromechanical retention.

• 한국응용곤충학회지
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• 제4권
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• pp.19-24
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• 1965

Tomato 즙배지에서 도열병균의 분생포자형성 및 균사의 생장에 환경요인이 주는 영향을 연구하고자 우선 광선조사조건(광원, 조사광선의 색, 조사시간), 전배양기간, 배지의 산도 등에 관하여 조사함으로써 간편한 방법으로 단시일내에 병원균의 분생포자를 다량 생성시킬 수 있는 방법을 모색코자 본실험을 하였다. (1) 24시간 계속 형광등에 조사시킨 것이 암처리한 것이나, 주기적으로 조사한 것보다 분생포자생장 및 균사생장을 증가시켰다. (2) 무피복, 적색, 황색, 청색의 Cellophane을 투과시킨 형광등조사에서 무피복이 가장 분생포자형성이 많았고 적색 및 황색, 청색 순으로 감소하였으며 균사생장에는 유의차가 없었다. (3) 도열병균도 광선의 주기적인 조사에 의하여 광선의 색에 관계없이 수상생장을 나타냈다. (4) 전배양기간이 길수록 광선조사에 의하여 분생포자의 형성은 증가되었지만 48시간에서 가장 좋았다. (형광등구). (5) 균총의 착색정도와 공중균사의 발달정도는 분생포자형성과 밀접한 관계가 있는 것 같으며 암색일수록 분생포자의 생장은 많으며 공중균사가 많으면 분생포자생성은 감소하는 경향이 있었다. 24시간 계속조사시킨 것이 가장 암색을 나타냈고 주기적인 광선조사는 중간정도였다. (6) pH 5-9에서 분생포자 및 균사생장을 볼 수 있었는데 그 최적은 pH 7이었으며 pH4 이하의 산도에서는 전연 병균의 생장을 볼 수 없었다.