In the present work, the influence of the ball-milling time, milling atmosphere and weight ratio of ball to powder on characteristics of was studied. Results show that, the grain sizes of the and CuO in the ball-milled powder mixture were significantly decreased with increasing the milling time. Those of each oxide ball-milled in Argon and Hexane atmosphere for 30 and 20 hour were about 98 and 84 nm, respectively. After milling of 20 hour in Hexane as PCA, the powder had a homogeneously mixed structure and the average size of powders was determined to about 230nm.

Recently warm compaction techniques are focused on and commercialization of one high-density compaction process in the P/M industry. Another development is a new SEGLESS using a developed lubricant that reduces ejection force at room temperature compaction. It is possible to achieve high-density by reducing lubricant amount. In this paper we confirmed that green density was 7.35 g/cm3 at 686MPa of compaction pressure when the new SEGLESS was applied to relatively lower temperature warm compaction process, such as 80℃.

본 연구는 poly(vinyl alcohol) (PVA)와 가교제 poly(strene sulfonic acid-co-maleic acid) (PSSA-MA)을 이용하여 제조된 막을 물/에탄올 계에 대한 투과증발 실험을 25, 35 및 45℃ 수식 이미지에서 수행하였다. 가교제의 함량은 7, 9, 11 wt.%를 사용하였으며, 원액의 조성은 무게비로 물 50, 20, 10 및 공비점인 4.4%에 대하여 조사하였다. 일반적인 투과증발 결과와 마찬가지로 가교제 함량의 증가 및 조업온도 증가에 따라 투과도 및 선택도에 대한 대표적 경향을 보여 주었다. 물 : 에탄올 = 10 : 90 조성에서 그리고 45℃ 수식 이미지에서 선택도 12003와 투과도 58.92g/m2·hr 수식 이미지를 PSSA-MA 11 wt%의 막이 보여 주었다.

We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with fatty acid (8A5H) and phospholipid (DLPE, DMPC, and DPPA). LB films of 8A5H monolayer and 8A5H-phospholipid mixture were deposited using the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured using cyclic voltammetry with three-electrode system, an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode at various concentrations(0.1, 0.5, and 1.0 mol/L) of NaClO4 solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate was 50, 100, 150 and 200 mV/s, respectively. As a result, LB films of fatty acid and phospholipid (8A5H/DLPE and DPPA) appeared irreversible process were caused by only the reduction current from the cyclic voltammogram and LB film of 8A5H-DMPC mixture was found to be caused by a reversible oxidation-reduction process.

본 연구는 중산간지(표고 450m)에서 한우 방목에 적합한 혼파조합을 선발하기 위한 시험으로 년(2년간) 남원 운봉에서 혼파조합별 식생비율의 변화, 건물 및 TDN 생산성, 채식량, 사료가치 등을 조사 및 분석 시험하였다. 한우방목 1년차는 주 초종의 비율이 감소하며, 오차드그라스 위주 혼파조합은 44.9%, 페레니얼 라이그라스 위주 혼파조합은 27.6%, 티머시 위주 혼파조합은 40.9%, 이탈리안 라이그라스 위주 혼파조합은 40.7% 감소하였다. 그

상온아스팔트 혼합물은 생산공정이나 시공 중에 naphtha나 kerosene을 사용하는 컷백 아스팔트와 같이 환경오염물질을 생성하지 않고 골재와 아스팔트 바인더를 가열하지 않기 때문에 가열아스팔트 혼합물에 비하여 환경친화적이며 경제적이다. 그러나 일반적으로 상온아스팔트 혼합물은 가열아스팔트 혼합물에 비해 내구성이나 수분민감성에서 미흡한 점이 많다. 본 연구에서는 상온아스팔트의 수분민감성과 내구성을 증진시킬 수 있는 섬유보강 상온아스팔트 혼합물(FEAM)에 대한 평가를 하였다. 최적 유화아스팔트량(OEC), 최적함수량(OWC) 그리고 최적 섬유보강제 첨가량(OFC)를 결정하기 위해서 마샬배합설계를 수정 개발하였다. 최적의 섬유보강 상온아스팔트 혼합물과 일반 상온아스팔트 혼합물을 제작하여 마샬안정도 시험, 간접인장강도 시험 및 회복탄성계수 시험을 실시하였고 그 결과를 가열아스팔트 혼합물의 결과와 비교하였다. 결과로 FEAM과 EAM 모두 마샬배합설계 기준으로 중간 교통량에 충분한 것으로 판명되었다. 또한 섬유보강에 의하여 일반 상온아스팔트 혼합물의 수분민감성과 내구성이 증진하는 효과도 얻을 수 있는 것으로 판명되었다

Many experimental and numerical approaches have been developed to evaluate paving materials and to predict pavement response and distress. Micromechanical simulation modeling is a technology that can reduce the number of physical tests required in material formulation and design and that can provide more details, e.g., the internal stress and strain state, and energy evolution and dissipation in simulated specimens with realistic microstructural features. A clustered distinct element modeling (DEM) approach was implemented In the two-dimensional particle flow software package (PFC-2D) to study the complex behavior observed in asphalt mixture fracturing. The relationship between continuous and discontinuous material properties was defined based on the potential energy approach. The theoretical relationship was validated with the uniform axial compression and cantilever beam model using two-dimensional plane strain and plane stress models. A bilinear cohesive displacement-softening model was implemented as an intrinsic interface and applied for both homogeneous and heterogeneous fracture modeling in order to simulate behavior in the fracture process zone and to simulate crack propagation. A disk-shaped compact tension test (DC(T)) with heterogeneous microstructure was simulated and compared with the experimental fracture test results to study Mode I fracture. The realistic arbitrary crack propagation including crack deflection, microcracking, crack face sliding, crack branching, and crack tip blunting could be represented in the fracture models. This micromechanical modeling approach represents the early developmental stages towards a 'virtual asphalt laboratory,' where simulations of laboratory tests and eventually field response and distress predictions can be made to enhance our understanding of pavement distress mechanisms, such its thermal fracture, reflective cracking, and fatigue crack growth.

Recently, there has been a remarkable trend of using aggregates at sizes smaller than 13 mm for drainage asphalt pavement (DAP) in order to reduce the noise generated between vehicle tires and road surface. These DAPs have their performance and durability seriously worsen after several years in-service due to the clogging of void space and the abrasion. This paper proposes the use of large size aggregates in porous asphalt mixtures to overcome these defects. Results of laboratory and field experiments on asphalt mixtures with several aggregate gradations are investigated and compared. The study focuses on advantages of DAP using large size aggregate and on particle size combinations containing no fine aggregates of size 2.36 mm or less, which have not been considered in current engineering practice.

The purpose of this study was to investigate the effect of dietary dae-chu(Rhamnace ziziphus, A), onion(Allium cepa L., O), mixture extracts (mulberry leaf, licorice root, pine needle, angelica gigas, jujube, onion, M) on serum glucose, lipid, enzyme, phosphorus levels in rats (Sprague-Dawley male rats, 357.03±7.08g). Serum calcium of onion group was significantly decreased (p〈0.05), but mixture extracts group of Cl (p〈0.05) and TBIL (total bilirubin, p〈0.05) were significantly increased. Serum glucose, total cholesterol, HDL-cholesterol and triglyceride were increased experimental rats than those of the normal rats. Mixture extracts was better than other groups for lipid metabolism. Also, GPT(glutamic pyruvic transaminase) and GOT(glutamic oxaloacetate transaminase) of onion extracts were protected to liver. So mixture and onion extracts were good drink for health.

We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with 4-octyl-4'-(5-carboxylpentamethyleneoxy)azobenzene (denoted as 8A5H) and phospholipid(L-α-dimyristoylphosphatidylcholine, denoted as DMPC). LB films of 8A5H monolayer and 8A5H-DMPC were deposited by using the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured by using cyclic voltammetry with a threeelectrode system, an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode at various concentrations(0.1, 0.5, and 1.0mol/L) of NaClO4 solution. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650mV and measured to the initial point. The scan rates were 50, 100, 150 and 200mV/s, respectively. As a result, LB films of 8A5H monolayer appeared irreversible process caused by only the oxidation current from the cyclic voltammogram and LB films of 8A5H-DMPC mixture were found to be caused by a reversible oxidation-reduction process.

본 연구는 산지 고랭지에서 방목용 초지생산성을 향상시키기 위하여 이 지역에 맞는 방목용 혼파조합을 선발하는데 목적이 있다. 따라서 본 실험은 대관령의 산지 고랭지에서 방목용 혼파조합이 목초의 식생비율 및 건물수량에 미치는 영향을 검토하여 방목에 적합한 혼파조합을 선발하고자 실시하였다. 실험은 1990년 8월부터 1993년까지 3년간 강원도 평창군 도암면 해발 840m에 위치한 실험포에서 수행하였다.

The synthesis and consolidation of titanium silicide by electro-discharge-sintering has been investigated. As-received Ti powder was in flaky shape and the mean particle size was , whereas the mean particle size of the pre-milled Si powder with angular shape was . Single pulse of 2.5 to 5.0 kJ/0.34g-elemental Ti and pre-milled Si powder mixture with the composition of Si was applied using capacitor. The solid with phase has been successfully fabricated by the discharge with the input energy more than 2.5kJ in less than Hv values were found to be higher than . The formation of occurred through a fast solid state diffusion reaction.