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.

OBJECTIVES : This study develops an evaluation method, which is useful to inspect pavement condition of specific boroughs. This is because pavement condition is broadly divided into five grades via visual inspection, which does not consider the types of deteriorations, and is decided by an investigator having a subjective viewpoint. This visual inspection method is not a satisfactory method for accurate maintenance when various deteriorations occur. METHODS: The performance model considers several factors such as crack, rutting, and IRI. This method is also modified from borough SPI based on SPI (Seoul Pavement Index). Considering limited budget of borough, PI (prediction index) is suggested, which is related to the grade of pavement condition evaluation and type of materials. Practical correlation review is also conducted with statistical verification by using the Monte Carlo simulation. RESULTS: The results of the study show that modified criteria are reasonable. First, the comparison between the visual inspection result and the SPI result indicates that the R-square value is sufficiently high. Second, through the common section, each evaluation method could be compared, and the result shows considerable similarity, which increases when the range is modified. Finally, PI for predicting remaining life and the random number SPI have common parts, which means that each indicator would be adequate to be used as an evaluation method. CONCLUSIONS : Comparison and analysis results show that the developed evaluation method is reasonable for specific boroughs where financial support is inadequate for the evaluation process by using the newer equipment. Moreover, for more accurate evaluation method, previous visual inspection data should be utilized, and the database of inspection equipment have to be collected.

수처리에 있어 막여과 기술은 안전한 처리수질의 보장, 시스템의 집약화 및 자동화 등의 장점으로 인해 활발히 도입되고 있다. 하지만 핵심 기자재인 막 모듈의 설계나 전체 정수처리 공정의 안정성 부분에 대해서는 아직 기술개발의 여지가 남아 있다. 본 연구에서는 막여과 공정의 연속 운전에 있어서 막오염을 완화시키기 위한 목적으로 수행하는 물리적인 역세척의 효율 향상과 더불어 이 때 발생하는 역세배출수를 막 모듈 외부로 원활히 배출할 수 있도록 한 가압식 막여과 기술과, 이 때 발생한 가압식 막여과 배출수를 이중 구조로 구획된 침지 막조 이용하여 원활히 처리할 수 있는 침지식 막여과 기술을 결합하여 기존 기술에 비해 고회수율의 달성은 물론, 집약적이고 실용적인 2단 막여과 정수처리 시스템을 개발하고자 하였다.

The vertical design spectrum for Korea, which is known to belong to an intra-plate region, is developed from the ground motion records of the earthquakes occurred in Korea and overseas intra-plate regions. From the statistical analysis of the vertical response spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. The developed design spectrum is valid for the estimation both spectral acceleration and displacement. The ratio of vertical to horizontal response spectrum for each record is calculated. Statistical analysis of the ratios rendered the vertical to horizontal ratio (V/H ratio). Subsequently the ratio between the peak vertical ground acceleration to the horizontal one is obtained.

The design spectrum for Korea, which is known to belong to an intra-plate region, is developed from the ground motion records of the earthquakes occurred in Korea and overseas intra-plate regions. The horizontal spectrum is defined as geometric mean spectrum, GMRotI50. From the statistical analysis of the geometric mean spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. The developed design spectrum is valid for the estimation both spectral acceleration and displacement.

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.

소에서 설사 등의 소화기질환, 폐렴 등의 호흡기질환, 유산 등의 번식장애를 유발하는 소 바이러스성 설사병(Bovine Viral Diarrhea, BVD)은 소 사육농가에서 경제적인 손실을 입히는 대표적인 생산성 저하 질병 중의 하나인데, 특히 유산, 사산 및 수태율 저하를 유 발하여 번식우 사육농가에 직접적인 피해를 입히고 있는 실정이다. 농림축산검역본부에 서는 BVD로 인해 1마리당 50,000원 정도의 손실로 연간 손실액이 최소 1천억 이상이라 고 추정하였고, 미국은 급성 BVD 감염으로 소 1마리당 약 400달러의 피해가 발생한다고 할 만큼 소 사육농가에 막대한 피해를 입히고 있지만, 우리나라에서 아직 법정 가축전염 병으로 지정되지 않아 체계적인 발생 상황이 확인되지 않고 있는 실정이다. 본 연구에서 는 한우 및 젖소 사육 농가를 대상으로 소 바이러스성 설사의 항원 양성률을 분석하여 소 바이러스성 설사병의 발생 현황을 확인하고자 하였다. 본 실험을 위해 4개도(강원, 전 북, 경남, 제주) 9개 목장에서 사육하고 있는 한우 송아지 및 젖소 육성우를 대상으로 분 변을 이용하여 PCR 방법으로 농장별, 생후 일령별 항원 양성률을 조사하였다. 한우 송아 지의 BVD 바이러스 항원 양성률을 조사한 결과 전체 조사 두수의 60.0%가 양성을 나타 내었고, 농장별로는 10.0%∼81.8%를 나타내어 농장별로 양성률에 많은 차이를 나타내었 다. 젖소 육성우의 경우 28.7% 양성률을 나타내었는데, 농가별로는 0%∼65.0%로 한우 송 아지와 마찬가지로 농장별로 차이를 보이고 있었다. 한우 송아지의 생후 일령(주령)별 양 성률을 조사한 결과 조사된 한우 송아지의 54.8%가 항원 양성률을 나타내었는데, 1주령 80.0%, 2주령 33.3%, 3∼4주령 45.5%, 5∼8주령 60.0%, 9주령 이상 50.0%를 나타내어 송 아지의 전체 연령대에 다양하게 항원 양성반응을 나타내었다. 소에서 번식장애 등의 손실 을 입히고 있는 BVD는 우리나라에서 예방백신이 개발되어 활용되고 있지만 소 사육농가 에서는 구제역 등과 같은 전염병에 비해 현실적으로 피해를 실감하지 못하고 있는 질병 이기도 하다. 따라서 본 연구 결과를 바탕으로 농가에서 임신 예정우, 송아지를 대상으로 예방백신 접종을 권장함으로써 그 피해를 경감시킬 수 있는 질병으로 사료된다.

갈색날개매미충은 최근 과수를 비롯한 다양한 식물에 대발생하여 생육을 저해하고 그을음병을 유발하는 등 문제가 매우 심각한 돌발성 해충이다. 본 연구는 위와 같은 갈색날개매미충의 친환경적인 방제를 위하여 식물추출물인 고삼추출물, 백합추출물, 목초액 등을 혼합비율을 달리하여 야외에서 성충을 대상으로 살충효과를 수행하였으며, 방제효율을 극대화하고 화학약제의 사용을 최소화하기 위하여 매미충류 등에 사용되고 있는 원제가 다른 화학약제 8종을 선발하여 살충효과를 검증하였다. 살충효과는 처리 3, 6일차 조사를 하였으며, 식물추출물의 살충력을 조사한 결과 고삼추출물, 백합추출물, 목초액 등 혼합된 제제가 83.3±5.1%의 살충력을 나타냈고 고삼추출물과 목초액이 혼합된 제제는 72.6±5.1%의 살충력을 보였다. 상용중인 화학약제의 살충효과는 Acetamiprid 92.8±5.1%, Dinotefuran 91.3±3.3%, Imidacloprid 91.3±3.3%, Etofenprox 89.9±1.9%, Deltamethrin 79.7±10.7%, Sulfoxaflor 69.6±10.0%, Bifenthrin 60.9±12.0%, Abamectin 53.6±5.1%의 살충력을 보였다. 효과가 우수한 제제에 대해서는 야외포장 포장관리용 자재로서 활용하여 방제효과를 극대화 하는데 참고로 활용하고자 한다.