Organic-inorganic hybrid coating films have been used to increase the transmittance and enhance the physical properties of plastic substrates. Sol-gel organic-inorganic thin films were fabricated on polymethylmethacrylate (PMMA) substrates using a dip coater. Metal alkoxide precursor tetraethylsilicate (TEOS) and alkoxy silanes including decyltrimethoxysilane (DTMS), 3-glycidoxypropyltrimethoxysilane (GPTMS), phenyltrimethoxysilane (PTMS), 3-(trimethoxysilyl)propyl methacrylate (TMSPM) and vinyltrimethoxysilane (VTMS) were used to synthesize sol-gel hybrid coating solutions. Sol-gel synthesis was confirmed by the results of FT-IR. Cross-linking of the Si-O-Si network during synthesis of the sol-gel reaction was confirmed. The effects of each alkoxy silane on the coating film properties were investigated. All of the organicinorganic hybrid coatings showed improved transmittance of over 90 %. The surface hardness of all coating films on the PMMA substrate was measured to be 4H or higher and the average thickness of the coating films was measured to be about 500 nm. Notably, the TEOS/DTMS coating film showed excellent hydrophobic properties, of about 97°.
AR (alkali resistant)-glass fibers were developed to provide better alkali resistance, but there is currently no research on AR-glass fiber manufacturing. In this study, we fabricated glass fiber from AR-glass using a continuous spinning process with 40 wt% refused coal ore. To confirm the melting properties of the marble glass, raw material was put into a (platinum) Pt crucible and melted at temperatures up to 1,650 °C for 2 h and then annealed. To confirm the transparent clear marble glass, visible transmittance was measured and the fiber spinning condition was investigated by high temperature viscosity measurement. A change in diameter was observed according to winding speed in the range of 100 to 700 rpm. We also checked the change in diameter as a function of fiberizing temperature in the range of 1,240 to 1,340 °C. As winding speed increased at constant temperature, fiber diameter tended to decrease. However, at fiberizing temperature at constant winding speed, fiber diameter tended to increase. The properties of the prepared spinning fibers were confirmed by optical microscope, tensile strength, modulus and alkali-resistance tests.
The semiconductor and display industries require the development of plasma resistant materials for use in high density plasma etching process equipment. Yttria (Y2O3) is a ceramic material mainly used to ensure good plasma resistance properties, which requires a dense microstructure. In commercial production, a sintering process is applied to reduce the sintering temperature of Y2O3. In this study, the effect of the addition of glass frit to the sintered specimen was examined when manufacturing yttria sintered specimens for semiconductor process equipment parts. The Y2O3 specimen was shaped into a Ø50 mm size and then sintered at 1,600 °C for 1~8 h. The characteristics, X-ray diffraction pattern, densities, contraction rate of the specimen, and swelling of the surface of the Y2O3 specimens were investigated as a function of the sintering time and glass frit addition. The Y2O3 specimen exhibited a density of over 4.9 g/cm3 as the sintering time increased, and the swelling phenomenon characteristics were improved by glass frit, by controlling particle size.
In this study, lanthanum boron silicate glasses were prepared with a composition of x Li2O-(60-x)B2O3-5CaO- 5BaO-7ZnO-10SiO2-10La2O3-3Y2O3 where x = 1,3,5,7, and 9 mol%. Each composition was melted in a platinum crucible under atmospheric conditions at 1,400 °C for 2 h. Clear glasses with a transmittance exceeding 85 % were fabricated. Their optical, thermal, and physical properties, such as refractive index, Abbe number, density, glass transition (Tg) and Knoop hardness were studied. The results demonstrated that refractive index was between 1.6859 and 1.6953 at 589.3 nm. The Abbe number was calculated using an equation for 589.3 nm (nd), 656.3 nm (nf) and 486.1 nm (nc) and was observed to be in the range from 57.5 to 62.6. As the Li2O content increased, the glass transition temperature of the optical glass decreased from 608 °C to 564 °C. If glass mold pressing is performed using a material with a low transition temperature and high mechanical strength, then the optical glasses developed in this study can be completely commercialized.
In this study, the glass melting properties are evaluated to examine the possibility of using refused coal ore as replacement for ceramic materials. To fabricate the glass, refused coal ore with calcium carbonate and sodium carbonate in it (which are added as supplementary materials) is put into an alumina crucible, melted at 1,200 ~ 1,500℃ for 1 hr, and then annealed at 600℃ for 2 hrs. We fabricate a black colored glass. The properties of the glass are measured by XRD (X-ray diffractometry) and TG-DTA (thermogravimetry-differential thermal analysis). Glass samples manufactured at more than 1,300℃ with more than 60 % of refused coal ore are found by XRD to be non-crystalline in nature. In the case of the glass sample with 40 % of refused coal ore, from the sample melted at 1,200℃, a sodium aluminum phosphate peak, a disodium calcium silicate peak, and an unknown peak are observed. On the other hand, in the sample melted at 1,300℃, only the sodium aluminum phosphate peak and unknown peak are observed. And, peak changes that affect crystallization of the glass according to melting temperature are found. Therefore, it is concluded that glass with refused coal ore has good melting conditions at more than 1,200℃ and so can be applied to the construction field for materials such as glass tile, foamed glass panels, etc.
지적장애아동은 낮은 지적능력으로 인해 주의집중력의 지속시간이 짧으며 정상적인 언어습득과 발달이 어렵다. 그러므로 사회성이 떨어지고 사람과의 유대감을 형성하는 것이 어려울 수 있다. 지적장애아동의 특성을 효과적으로 개선하는 방법에는 동물을 통한 매개 활동이 있다. 동물은 아동과의 상호작용을 통하여 언어능력을 향상 시키고, 인지발달을 촉진시킨다. 그리고 의사소통이나 상호작용이 미숙한 아동에게 동물매개활동은 의사소통 및 자기표현 기술을 습득하는 데 유용하게 작용할 수 있다. 본 연구는 동물매개활동 프로그 램이 지적장애아동의 주의집중력과 언어능력에 미치는 효과를 알아보기 위해 J도 I시 특수 장애 학교에 다니고 있는 만 14세에서 16세인 지적장애아동 3명을 대상자로 선정하였다. 연구는 주 1회, 8주간, 총 16회기 동안 진행하였다. 사전ㆍ사후 검사 도구로는 Harris & Harris(1984)의 집중력 격자판 검사와 수용·표현 어휘력 검사(Receptive and Expressive Vocabulary Test: REVT)를 이용하여 연구 대상자들의 주의집중력과 수용·표현 어휘력의 비교분석을 하였다. 이 연구를 통해 동물매개활동 프로그램이 지적장애아동의 주의집중력과 수용·표현 어휘력을 유의미한 수준으로 향상시켜 주었음을 관찰할 수 있었다.
In this study, glass fibers are fabricated via a continuous spinning process using manganese slag, steel slag, and silica stone. To fabricate the glass fibers, raw materials are put into an alumina crucible, melted at 1550℃ for 2 hrs, and then annealed at 600℃ for 2 hrs. We obtain a black colored glass. We identify the non-crystalline nature of the glass using an XRD(x-ray diffractometer) graph. An adaptable temperature for spinning of the bulk marble glass is characterized using a high temperature viscometer. Spinning is carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of 1109℃ to 1166℃ , while the winder speed is in the range of 100rpm to 250rpm. We investigate the various properties of glass fibers. The average diameters of the glass fibers are measured by optical microscope and FE-SEM. The average diameter of the glass fibers is 73 μm at 100rpm, 65 μm at 150rpm, 55 μm at 200rpm, and 45 μm at 250rpm. The mechanical properties of the fibers are confirmed using a UTM(Universal materials testing machine). The average tensile strength of the glass fibers is 21MPa at 100rpm, 31MPa at 150rpm, 34MPa at 200rpm, and 45MPa at 250rpm.
Anti-reflection thin films are fabricated on glass substrates using the screen printing method. Tetra ethyl silicate(TEOS) and methyl tri methoxy silane(MTMS) are used as starting materials and buthyl carbitol acetate(BCA) and buthyl cellusolve(BC) are mixed to improve the viscosity of the solution. Anti-reflection thin films are fabricated according to the number of the screen mesh and the characteristics improve as the mesh size increases. The transmittance and reflectance of the coated thin film using 325 mesh are about 94 % and 0.43 % in the visible wavelength. The thickness and refractive index of the AR thin film are 107 nm and n = 1.26, respectively.
현대사회는 반려동물을 기르는 가정이 증가하고 있다. 인간을 비롯한 반려동물도 일상 생활 속에서 피부질환의 위험에 놓여있고, 이에 따라 피부에 자극을 주지 않는 천연 세정 제품에도 큰 관심이 집중되고 있다. 천연제품이 대중화되어가고 있지만, 편리성과 즉효성을 장점으로 내세우는 일반 세제와 비누보다 천연제품의 이점을 보여주는 정확한 사례가 적다. 이를 알아보기 위해 기존에 사용되었던 세정제 제품을 직접 제작한 천연비누로 교체하였을 때의 피부변화를 실험하였다. 더 정확한 결과 값 측정을 위해 일제히 통제된 환 경에서 지정된 15마리의 실험견들을 선별하고, 유 수분 측정기와 관찰현미경을 이용해 연구를 진행하였고, 천연비누의 교체로 유분, 수분 함량은 증가하였고, 개선된 피부 상태를 확인했다.
General D-glass(Dielectric glass) fibers are adaptable to PCBs(Printed circuit boards) because they have a low dielectric constant of about 3.5~4.5. However, very few papers have appeared on the physical characteristics of D-glass fibers. D-glass fibers were fabricated via continuous spinning process using bulk D-glass. In order to fabricate the D-glass, raw materials were put into a Pt crucible, melted at 1650℃ for 2 hrs, and then annealed at 521 ± 10℃ for 2 hrs. We obtained transparent clear glass. The transmittance and adaptable temperature for spinning of the bulk marble glass were characterized using a UV-visible spectrometer and a viscometer. Continuous spinning was carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of 1368℃ to 1460℃, while the winder speed was between 100 rpm and 200 rpm. We investigated the physical properties of the D-glass fibers. The average diameters of the glass fibers were measured by optical microscope and FE-SEM. The average diameters of the D-glass fibers were 21.36 um at 100 rpm and 34.06 um at 200 rpm. The mechanical properties of the fibers were confirmed using a UTM(Universal materials testing machine). The average tensile strengths of the D-glass fibers were 467.03 MPa at 100 rpm and 522.60 MPa at 200 rpm.
E (Electric) -glass fibers are the most widely used glass fibers, taking up 90 % of the long glass fiber market. However, very few papers have appeared on the physical characteristics of E-glass fibers and how they depend on the fiberizing temperature of fiber spinning. Glass fiber was fabricated via continuous spinning process using bulk E-glass. In order to fabricate the E-glass specimen, raw materials were put into a Pt crucible and melted at 1550 oC for 2hrs; mixture was then annealed at 621 ± 10 oC for 2hrs. The transmittance and adaptable temperature for spinning of the bulk marble glass were characterized using a UV-visible spectrometer and a viscometer. Continuous spinning was carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of 1175~1250 oC, while the winder speed was fixed at 500 rpm. Subsequently we investigated the physical properties of the E-glass fiber. The average diameter of the synthesized glass fiber was measured by optical microscope. The mechanical properties of the fiber were confirmed using a UTM (universal materials testing machine); the maximum tensile strength was measured and found to be 1843 ± 449MPa at 1225 oC.
E-glass (electrical glass) fiber is the widely used as a reinforced composite material of PCBs (printed circuit boards). However, E-glass fiber is not stable because it has a dielectric constant of 6~7. On the other hand, D-glass (dielectric glass) fiber has a low dielectric constant of 3~4.5. Thus, it is adaptable for use as a reinforcing material of PCBs. In this study, we fabricated D-glass compositions with low dielectric constant, and measured the electrical and optical properties. In the glass composition, the boron content was changed from 9 to 31 wt%. To confirm the dependence of the dielectric constant on melting properties, D-glass with 22 wt% boron was melted at 1550 oC and 1650 oC for 2hrs. The glass melted at 1650 oC had a lower dielectric constant than the glass melted at 1550 oC. Therefore, the D-glass with boron of 9~31 wt% was fabricated by melting at 1650 oC for 2hrs, and transparent clear glass was obtained. We identified the non-crystalline nature of the glass using an XRD (x-ray diffractometer) graph. The visible light transmittance values depending on the boron contents were measured and found to be 88.6%~ 82.5%. Finally, the dielectric constant of the D-glass with 31 wt% boron was found to have decreased from 4.18 to 3.93.
본 프로그램은 저소득 결손가정 아동을 대상으로 원예활동 및 그림그리기 병행활동을 실시하여 정서증진의 기회를 제공하고, 이를 통해 주의력을 향상시키고자 실시하였다. K-HTPF 및 매 회기별 대상자의 그림을 통해 사회성, 안정감, 역동성 및 표현력 등이 증진되었음을 볼 수 있었다. 또한 주의집중력 향상을 살펴보기 위한 ADS 검사결과에서는 충동성 점수가 낮아지고, 일관성이 높아진 결과를 통해 아동의 주의집중력이 향상되었음을 확인할 수 있었다. 앞으로 정서발달 및 주의집중력에 관한 신뢰도를 확보하기 위한 원예활동연구를 추가 수행할 예정이다.
In this paper, changes in the intensity (e.g., central pressure and maximum sustained wind speed) of Tropical Cyclone (TC) in summer in the regions located at 30 oN in East Asia from 1988 to 1991 were found. The intensity of TC from 1991 to 2007 was much higher than that of TC from 1965 to 1988. The reason for this was that the frequency of TCs passing China from 1991 to 2007 was much lower than that of TCs from 1965-1988 because a northeasterly wind caused by high-pressure circulation in East Asia got severer along the East Asian coast. Instead, TCs moved from the eastern region of the Tropical West Pacific to Korea and Japan mainly after passing the East China Sea due to the low-pressure circulation strengthened in the subtropical waters of East Asia. In addition, low Vertical Wind Shear (VWS) was created along the mid-latitude regions of East Asia and the main path of TCs from 1991 to 2007. Most of the regions in the Northwestern Pacific showed higher Sea Surface Temperature (SST) from 1991 to 2007, and had a good environment where TCs were able to maintain a higher intensity on the mid-latitude. In particular, a low sensible heat flux occurred due to high snow depth in East Asia in the spring of 1991 to 2007. Accordingly, the lower layer of East Asia showed high-pressure circulation, and the sea surrounding East Asia showed low-pressure circulation. Thus, the typical west-high, east-low pattern of winter atmospheric pressure was shown. The possibility of snowfall in East Asia in spring to be used as a factor for predicting the summer intensity of TC in the mid-latitude regions of East Asia was insinuated. The characteristics of TC in a low-latitude region were the same in Korea. The latest intensity of TCs got higher, and the landing location of TCs gradually changed from the west coast to the south coast.
This study found that tropical cyclones (TCs) formed for fall in 2007 over the western North Pacific were distributed in high-latitudes comparing to 56-year (1951-2006) climatological mean. The frequency and latitude of TC genesis became higher than 56-year climatological mean from September onward in 2007 and all the TCs that formed to the north of 20°N was also distributed after September in 2007. These characteristics of TC genesis for fall in 2007 could be confirmed through analyzing various variables, such as a large-scale atmospheric circulation, outgoing longwave radiation (OLR), vertical zonal wind shear, and sea surface temperature (SST). On the other hand, a frequency of the TC that occurred to the north of 20°N showed a clear interdecadal variation and its decreasing trend was distinctive in recent years. Its intensity was also weaker that TCs that did to the south of 20°N. However, a latitude of TC genesis showed an increasing trend until recent years, whose variation was consistent with trend that through a SST analysis, warm SST went north in recent years.
본 연구는 원예식물을 이용한 실내소형 컨테이너정원 조성 및 원예치료활동 등에 활용하기 위한 컨텐츠를 개발하기 위하여 실시하였다. 어린이 교육용 컨텐츠로는 주로 향이 나는 식물과 움직이는 미모사나 소리에 반응하는 무초나 식충식물 컨텐츠를 활용하여 흥미를 유발하거나 동화정원을 만들어 어린이 동화를 중심으로 인형을 만들어 배치하고, 동물형태 토피어리를 이용하며, 밀폐형 비바리움컨텐츠를 만들어 식충식물, 식물+물고기, 식물+곤충, 식물+애완용동물(거북이 등)으로 조성할 수 있을 것이다(Table 1). 또한 노인을 대상으로 하는 컨텐츠의 경우 노인의 건강상태를 최우선적으로 고려하여 원예컨텐츠를 계획하는 것이 필요하며 일반적으로 노인의 건강정도는 양호한 경우, 휠체어를 사용하는 경우, 관절이 부자유 하거나 치매를 앓고 있는 경우로 구분되며, 또한 신체적 장애 외에도 심리적 장애와 사회적인 장애를 고려하여야 할 것이다(Table 2, 3).
오늘날 식물의 약용적, 심리적, 공기정화 기능들이 심도 깊게 연구되고 있으며 이러한 연구들을 통합한 원예활동 및 원예치료활동에 응용하기 위한 연구가 요구되고 있다. 따라서 이러한 연구를 위하여 다양한 원예활동범위를 넓히고 조경사업, 원예치료활동, 원예관련사업 다각화를 위한 조사를 실시하였다.
본 연구는 사계절과 월별로, 원예식물을 이용한 실내소형 컨테이너정원 조성 및 원예치료활동 등에 활용가능한 컨텐츠를 개발하기 위하여 식물의 생육시기와 기능을 분류하고, 절기별로 컨텐츠를 제안하였다. 관상화훼학, 약용학, 관엽식물, 채소학 등의 다수의 참고자료를 이용하였으며, Table 1은 장식식물의 유형에 따른 컨텐츠, Table 2는 채소/약용식물의 이용이나 건강에 미치는 효과를 기준으로 정리한 개발가능한 컨텐츠의 일례이다.