A Cu-15Ag-5P filler metal (BCuP-5) is fabricated on a Ag substrate using a high-velocity oxygen fuel (HVOF) thermal spray process, followed by post-heat treatment (300oC for 1 h and 400oC for 1 h) of the HVOF coating layers to control its microstructure and mechanical properties. Additionally, the microstructure and mechanical properties are evaluated according to the post-heat treatment conditions. The porosity of the heat-treated coating layers are significantly reduced to less than half those of the as-sprayed coating layer, and the pore shape changes to a spherical shape. The constituent phases of the coating layers are Cu, Ag, and Cu-Ag-Cu3P eutectic, which is identical to the initial powder feedstock. A more uniform microstructure is obtained as the heat-treatment temperature increases. The hardness of the coating layer is 154.6 Hv (as-sprayed), 161.2 Hv (300oC for 1 h), and 167.0 Hv (400oC for 1 h), which increases with increasing heat-treatment temperature, and is 2.35 times higher than that of the conventional cast alloy. As a result of the pull-out test, loss or separation of the coating layer rarely occurs in the heat-treated coating layer.
Since its introduction to the Korean peninsula, the Chinese character became the only official script and was revered by the rulers. In post modern era, with the intervention of Western forces and the awakening of Korean national consciousness, Korea began to abolite Chinese characters. This study examines the process of dismissal Chinese characters in post-modern Korea and the policy of Chinese characters education from the perspectives of linguistic sociology and theory of Chinese characters cultureology, and analyzes the reasons and rationality of its development, as well as the significance of Chinese characters education in Korea in the new era, based on historical materials such as relevant literature, news magazines, and policy decrees.
CO2 separation technology for carbon capture, which is one of the hot issues to reduce greenhouse gases from industrial flue gas, has been intensively investigated so far. Despite of several benefits, the membrane technology has some obstacles like large-scale module fabrication, membrane durability, need of pre-treatment or high pressure drive for its industrial application. Also, the power plant flue gas with normally 10~20% of CO2 content should be concentrated upto 99% for being compressed and liquefied to transportable CO2 by pipeline, indicating the need of high selective membrane process as well as high recovery. In this work, the possibility of membrane process for post-combustion treatment in terms of recent technology will be announced. The practically applicable process for CO2 capture also be suggested briefly.
이 연구는 파키스탄에서 9/11 테러 이후 외교정책 결정 과정을 추적하기 위해 4단계 "위기에서의 국가 행동 모델"을 적용했다. 그것은 알카에다의 미국에 대한 불길한 공격과 테러에 맞서 싸우기 위한 부시 대통령의 후속 선언이 t1 단계의 세계와 지역의 정치 안보 차원을 변화시켰다고 주장한다. 이웃 국가인 파키스탄의 지원은 테러와의 전쟁에서 불가피했고, 미국은 이슬람 바드의 협력을 얻기 위해 강압적인 외교를 취했다. 결과적으로, 미국의 요구를 수용하지 않을 경우 파키스탄은 국가의 기본 가치/목표에 대한 위협을 인식하고 동시에 시간 압박은 t2 단계에서 의사결정자들의 심리적 스트레스를 증폭시켰다. 따라서 의사결정 포럼은 t3 단계에서 시작되었고 파키스탄은 외교 정책 위기를 완화시킨 t4 단계로 미국에 합류하기로 결정했다.
The carbon capture and storage (CCS) technology from industrial flue-gas has been an important environmental issue in these days. However, membrane process has a number of breakthrough-point to commercialization in scale-up. In this work, process optimization for high purity and high CO2 recovery with lower the capture cost has been investigated. Lab-made membrane pilot process using real flue gas has been also set up to derive industrial factor.
Membrane is a relatively new industrial gas separation technology and has been studied as an alternative CO2 capture technologies to amine absorption. Membrane processes have a merit such as low energy use, small footprint, no by-products formation, and simple operating condition. When applied to flue gas CO2 capture, low CO2 concentration and normal pressure of flue gas stream places a practical limits on the membrane operation. The up-to-date membranes should allow module performance to rise to levels practical for fossil-fuel power station use. In this talk, membrane module is being evaluated for flue gas treatment. Membrane processes using several membranes, which are now being studied under the R&D projects granted by KCRC, are investigated to capture CO2 from the simulated gas.
Flat sheet membranes consisting of a selective layer and a porous support usually require gutter layer to reduce the bulk pores of the substrates. The gutter layer mitigates the geometric restrictions of support, which enables selective layer to have defect-free morphology with thin thickness (< 100 nm). For this reason, the gutter layer has been introduced to many industrial membranes, and the systematical studies of the effects of the gutter layer properties on membrane performance should be needed. Herein, we introduced several gutter layers with different thicknesses into graphene oxide intercalated polymer TFC membranes to determine the relationship between gutter layer properties and total membrane performances. This study provides more practical insight to determine the optimum gutter layer properties in designing TFC membranes.
연소 후 생성되는 연소가스 중 CO2는 온실가스 기체중 하나로, CO2를 처리하기 하기 위해 CCS 기술 개발이 세계적으로 주목 받고 있다. 하지만 단일막을 이용한 CO2 포집 공정에서는 약 14%의 CO2를 포함한 연소 배기가스로부터 고 순도, 고회수율을 달성하기란 매우 어렵다. 본 연구에서는 다단막 공정 디자인 및 다양한 운전 변수를 통하여 14%의 CO2를 가지고 있는 혼합모사가스로부터 순도 73% 회수율 74%의 포집 효율을 얻을 수 있었다.
The carbon capture and storage (CCS) technology from industrial flue-gas is an important environmental issue these days. Membrane process can be competitive technology for its relatively small footprint and eco-friendly system. Many membrane modules with high selectivity and excellent flux have been developed so far. However, the high purity and recovery for CO2 capture can be achieved by optimization of operating conditions such as membrane area, feed/permeate pressure ratio and humidity of flue gas as well as membrane permeance or selectivity. In this study, we discuss the effect of operating parameters for high CO2 purity and recovery at permeate side. Using polymeric hollow fiber membrane, the single membrane process was tested to figure out the effect of feed flow rate, pressure ratio, membrane area and moisture content.
According to a simple survey on the current status of the assembly line design, it was found that trial and error methods on the basis of experiences have been used mainly in domestic manufacturing industries, even though there exist a lot of excellent line balancing studies. It seems that more practical researches should be carried out to develop user-oriented line balancing tools especially for small and medium-sized enterprises. This study presents a design of the line balancing tool which can support the line balancing tasks of nonspecialists. The proposed design tool is composed of three major modules: pre-process, line balancing, and post-process. In particular, pre-process and post-process are newly proposed to increase its ease of use. We applied the proposed design to a test problem and test result showed that our practical method may contribute to enhance the efficiency of production operations management.
프로그램 개발에 있어 디버깅은 매우 중요한 요소이다. 개발 과정에서 디버깅을 통해 버그를 대부분 잡을 수 있지만 제품이 출시된 이후에도 프로그램 버그를 잡을 수 있는 시스템이 필요하다. 이를 위해 포스트 모템 디버깅에 대해 살펴보고 프로세스 덤프에 대해 논의한다. 또한 프로그램이 다운되었는데 프로세스 덤프가 생성되지 않는 상황에 대해 원인을 분석해 보도록 한다. 아울러 검증된 예외 핸들러라 하더라도 프로세스 덤프를 남기지 못하는 상황을 이해하고 이런 상황을 타개하기 위해 EHModule(Exception Handler Module)를 구현한다. 구현한 EHModule의 핵심 루틴을 설명하고 해당 모듈의 특징 및 효용성에 대해 언급한다.