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.

본 연구는 LED 조명의 조도와 과제 난이도가 장기기억에 미치는 영향을 검증하기 위해 실시된 연구이다. 본 연구의 조도는 400 lx와 1,000 lx 조건으로 처치하였으며, 과제 난이도는 4단어 학습(쉬운 과제)과 7단어 학습(어려운 과제)으로 설정하였다. 그리고 학습한 과제의 기억률을 종속변인으로 사용하였다. 본 연구에 참여한 실험참가자는 총 64명이며, 각 조건 당 16명의 참가자가 할당되었다. 연구결과 상대적으로 어두운 400 lx 조건이 68.49%로 1,000 lx 조건의 56.03% 보다 기억률이 높은 것으로 나타났다. 아울러 쉬운 과제 조건이 67.97%의 기억률을 보여 56.55%의 어려운 과제에 비해 기억률이 더 좋은 것으로 나타났다. 그러나 조도와 과제 난이도의 상호작용효과는 통계적으로 유의미성이 나타나지 않았다. 본 연구를 통해 상대적으로 어두운 조건에서 장기기억이 효과적일 수 있음을 재검증하였고, 아울러 장기기억은 요커스-도드슨 법칙을 따르지 않을 수 있음을 간접적으로 탐색하였다.

하⋅폐수처리 MBR 공정을 운영함에 있어서 특정 오염물에 따른 멤브레인 회복률 저하를 자주 경험하게 되며, 이에 따른 화학세정 시 막오염 물질 제거에 필요한 약품선택에 많은 어려움을 겪는다. 본 연구의 목적은 하폐수 성상의 MBR 처리 시 발생할 수 있는 Ca 막오염에 대해서 다양한 세정약품 적용을 통한 멤브레인의 회복률 증대 방안을 찾고자 하는 것에 있다. 본 연구는 K 폐수처리시설에서 1년간 운영한 (주)에코니티의 분리막을 샘플링하여 투과도 측정 및 막표면 분석 후 막오염 물질을 우선적으로 확인하였으며, 이에 따른 각종 화학약품의 적용실험을 통하여 최적약품 도출 및 적용성을 평가하고자 하였다.

In this paper, we investigated the change of sectional shape according to the tension when the reed wire was rolled. When rolling is performed, the tension acting on the reed wire acts in the opposite direction of the rolling progress and prevents twisting or bending phenomenon. The shape of the cross section was changed according to the tension acting on the reed wire, and the reed wire was rolled by continuously rolling the flat rolled wire and the tension was applied to the reed wire to control the simulation. As a result of the experiment, it was confirmed that the dimensions of the thickness and width after rolling can be adjusted through the tension acting on the lead wire. It was also confirmed that as the tension increased, the length of the lead wire increased and the residual stress increased.

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.

In this study, ZrO2 ceramic ink was formulated for additive manufacturing three dimensional structure using dispenser printing technique. Ceramic ink with various ZrO2 loading (30, 40, 50vol%) was prepared to evaluate their rheological properties and printability. High ZrO2 loading ZrO2 ceramic ink showed higher elastic modulus and improved shape retention, when the ceramic ink was printed and sintered at 1450 oC for 1h. Microstructural analysis of printed ZrO2 objective indicated that high ZrO2 loading objective showed lower porosity and smaller pore size.

Ceramic ink-jet printing has become a widespread technology in ceramic tile and ceramicware industries, due to its capability of manufacturing products on demand with various designs. Generally, thermally stable ceramic inks of digital primary colors(cyan, magenta, yellow, black) are required for ink-jet printing of full color image on ceramic tile. Here, we synthesized an aqueous glass-ceramic ink, which is free of Volatile organic compound(VOC) evolution, and investigated its inkjet printability. CoAl2O4 inorganic pigment and glass frit were dispersed in aqueous solution, and rheological behavior was optimized. The formulated glass-ceramic ink was suitably jetted as single sphere-shaped droplets without satellite drops. After ink-jet printing and firing processes, the printed glass-ceramic ink pattern on glazed ceramic tile was stably maintained without ink spreading phenomena and showed an improved scratch resistance.

Cherry leaf roll virus(CLRV)는 group IV positive sense ssRNA viruses, Nepovirus로 분류되는 식물병원성 바이러스이다. CLRV는 체리 등 목본 및 완두 등 콩과 작물을 자연 기주로 하며, 실험적으로 약 36개 과 이상의 넓은 기주 범위를 가지고 있어 국가적, 경제적 및 농가 개인적 피해를 야기 할 가능 성이 보고되고 있다. 현재 CLRV를 검출하는 방법으로 역전사(reverse transcription; RT)-nesdted 중 합효소연쇄반응(polymerase chain reaction; PCR) 이 활용되고 있으며, 다양한 기주로부터 CLRV를 검출하기 위해서는 검출 감도, 특이성, 반응 시간, 단순성 등이 중요 요소였다. 그러나 RT-nested PCR은 두 단계로 구성되어 있어 단순하지 않고, CLRV를 검출하는데 약 10시간 이상의 반응 시간이 소 요되었다. 이번 연구에서는 등온증폭법을 이용하여 단순하고 신속하게 CLRV를 검출하는 방법을 개발하 였다. 등온증폭 반응은 RT-nested PCR과 동등한 검출 감도로 CLRV를 검출 하였다. 그러나 반응 시간 을 약 2시간 수준으로 단축하였으며, 6개 영역을 사용하는 등온증폭 프라이머의 사용으로 더욱 특이적 으로 증폭 할 수 있었다.

Recycled cenosphere, which is a hollow shaped particle from fly ash, has become attractive as a building material due to its light weight and excellent heat insulation and soundproof properties. In this paper, we investigated the effect of cenosphere size on the physical and optical properties. High brightness of cenosphere as raw material is required for a wide range of ceramics applications, particularly in fields of building materials and industrial ceramic tiles. Cenospheres were sorted by particle size; the microstructure was analyzed according to the cenosphere size distribution. Cenospheres were generally composed of quartz, mullite, and amorphous phase. Colour measurement corresponding to chemical composition revealed that the contents of iron oxide and carbon in the cenospheres were the major factors determining the brightness of the cenospheres.

Ink-jet printing techniques with ceramic ink, which contains ceramic pigments as colorant, are in increasingly use in the ceramic industry. Generally, ceramic pigments that are produced by conventional method show diameters of several micrometers; these micrometer sized particles in the ink-jet printing process can cause undesirable behavior such as print head nozzle clogging. To prevent this problem, a particle size reduction process is required. In this study, CMYK (cyan, magenta, yellow, black) pigments were synthesized via solid state method. Each pigment particle was milled to submicron size by an attrition mill. The effects of micronizing on the morphology, mechanical property, crystal structure and color property of the CMYK ceramic pigments were investigated by field emission scanning electron microscopy (FE-SEM), particle size analysis (PSA), X-ray diffraction (XRD) and CIE L*a*b*.

Recently, there have been many efforts to establish suitable processes for recycling fly ash, which is produced in thermal power plants and which poses serious environmental problems. Use of fly ash as a major ingredient of ceramic tiles can increase fly ash utilization, as well as reduce the cost of raw materials in ceramic tile production. In this study, the effects of fly ash addition on ceramic tile properties such as bending strength, water absorption and porosity were investigated. A manufacturing process of ceramic tile was developed for utilization of fly ash with high carbon content. In this approach, it is important to hold the ceramic tiles at a temperature that is sufficient for carbon oxidation, before the pores supplying oxygen to the inside of the ceramic tile are sealed. Ceramic wall tiles were manufactured with 0-40wt% of fly ash addition. The water absorption and porosity of the fired body were slightly changed with increasing fly ash content up to 30wt% and decreased with greater amounts of fly ash addition. The bending strength of ceramic tile including 10wt% fly ash increased, reaching a level comparable to that of ceramic tile without fly ash.

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.

Using the ultrasonic pyrolysis method, spherical SiO2 powders were synthesized from aqueous SiO2 sol as a starting material. The effects of pyrolysis conditions such as reaction temperature, SiO2 sol concentration, and physical properties of precursor were investigated for the morphologies of the resulting SiO2 powders. The particle size, shape, and crystallite size of the synthesized SiO2 powders were demonstrated according to the pyrolysis conditions. Generally, the synthesized SiO2 particles were amorphous phase and showed spherical morphology with a smooth surface. It was revealed that increased crystallite size and decreased spherical SiO2 particle size were obtained with increases of the pyrolysis reaction temperature. Also, quantity of spherical SiO2 particles decreased with the decrease in the concentration and surface tension of the precursor.

SrAl2O4: Eu2+ and Dy3+ phosphorescent phosphors were synthesized using the polymerized complex method. Generally, phosphorescent phosphors synthesized by conventional solid state reaction show a micro-sized particle diameter; thus, this process is restricted to applications such as phosphorescent ink and paint. However, it is possible to synthesize homogeneous multi-component powders with fine particle diameter by wet process such as the polymerized complex method. The characteristics of SrAl2O4: Eu2+ and Dy3+ powders prepared by polymerized complex method with one and two step calcination processes were comparatively analyzed. Temperatures of organic material removal and crystallization were observed through TG-DTA analysis. The crystalline phase and crystallite size of the SrAl2O4: Eu2+ and Dy3+ phosphorescent phosphors were analyzed by XRD. Microstructures and afterglow characteristics of the SrAl2O4: Eu2+ and Dy3+ phosphors were measured by SEM and spectrofluorometry, respectively.

Geopolymers have many advantages over Portland cement, including energy efficiency, reduced greenhouse gas emissions, high strength at early age and improved thermal resistance. Alkali activated geopolymers made from waste materials such as fly ash or blast furnace slag are particularly advantageous because of their environmental sustainability and low cost. However, their durability and functionality remain subjects for further study. Geopolymer materials can be used in various applications such as fire and heat resistant fiber composites, sealants, concretes, ceramics, etc., depending on the chemical composition of the source materials and the activators. In this study, we investigated the thermal properties and microstructure of fly ash and blast furnace slag based geopolymers in order to develop eco-friendly construction materials with excellent energy efficiency, sound insulation properties and good heat resistance. With different curing times, specimens of various compositions were investigated in terms of compressive strength, X-ray diffraction, thermal property and microstructure. In addition, we investigated changes in X-ray diffraction and microstructure for geopolymers exposed to 1,000 oC heat.

퇴적물 준설은 수서생태계에서 오염물질을 영구적으로 제거하는 것으로 수서생태계 복원에 있어서 효율적인 방법으로 여겨진다. 본 연구에서는 수괴의 산소 요구율의 계산을 통해 마산만의 퇴적물 준설이 수질에 미치는 영향을 정량화하였다. 이를 위해 수질 및 저질 모델이 포함된 생태계 모델을 마산만에 적용시켰다. 모델 계산 결과, 육상 오염원이 감소할수록 수괴의 산소 요구율이 다소 증가한 반면에 만내측과 만외측의 준설에 의해서는 산소 요구율이 크게 증가하였다. 이러한 결과는 퇴적물 준설이 마산만 수질을 더욱 개선시킬 수 있음을 의미한다. 산소 요구율과 퇴적물 산소 요구량의 상관관계식을 통해 육상 부하량 10 % 감소에 의한 수질 개선효과에 상당하는 퇴적물 준설 면적이 만내측에서는 1.68㎢이며, 만외측에서는 3.15㎢임을 계산하였다. 이는 마산만 수질 개선을 위해서는 만내측의 퇴적물 준설이 효율적 방법임을 의미한다.

해역에서의 체류시간은 제한된 영역을 채우는 수체나 오염물질이 잔류하는 시간을 의미하며, 서로 다른 수체간의 물리적 특성을 비교하는 데 사용되고 있다. 거제만으로 유입되는 육상기원 또는 양식기원 입자물질의 잔류시간을 알아보기 위해 입자추적모델이 포함된 EFDC를 이용하여 입자물질 체류시간을 계산하였다. 계산된 입자물질의 체류시간은 내만에서 약 65일이었는데, 이 결과는 거제만 내측으로 유입되는 입자물질이 외해에 도달하기까지 약 2달 이상의 시간이 소요됨을 의미한다. 이 체류시간은 거제만 전역에 걸쳐 조석의 흐름에 따라 다르게 나타났으며, 해역에 유입된 입자물질의 거동이 해역의 물리적 특성에 의해 결정됨을 의미한다. 입자물질 체류시간의 공간적인 분포특성을 통해 거제 내만의 해수교환이 원활하지 않은 것을 알 수 있으며, 이로 인해 수질오염문제에 취약할 수 있다는 것을 알 수 있다.