WC and dense WC-10 vol%Co materials with grain size of~1 were synthesized by high-frequency induction heated combustion synthesis (HFIHCS) method in one step from elemental powders of W, C and Co within several minutes. Simultaneous combustion synthesis and densification were accomplished under the combined effects of an induced current and mechanical pressure. In the absence of cobalt additive, WC can be formed, but its relative density was low (about 73%) under simultaneous application of a 60 MPa pressure and the induced current. However, in the presence of 10 vol.%Co, the relative density increased to 99% under the same experimental condition. The percentages of the total shrinkage occurring before and during the synthesis reaction of WC-10 vol.%Co were 5% and 51%, respectively. The fracture toughness and hardness values of WC-10 vol.%Co were 10 MPa . m and 1840 kg/, respectively.

Based on the previous results of the equilibrium and batch adsorptions, the removal efficiency of the two-step surface-modified activated carbon (2ndAC) for heavy metal ions such as Pb, Cd, and Cr in fixed column was evaluated by comparing with that of the as-received activated carbon (AC) and the first surface-modified activated carbon (1stAC). The order of metal removal efficiency was found as 2ndAC 〉 1stAC 》 AC, and the efficiency of the 2ndAC maintained over 98% from the each metal solution. Increase of the removal efficiency by the second surface modification was contributed to maintain favorable pH condition of bulk solution during adsorption process. The removal of the heavy metals on the 2ndAC was selective with Pb being removed in preference to Cr and Cd in multicomponent solutions and slightly influenced by phenol as the organic material.

The two-step surface modifications of activated carbon was carried out to improve the adsorption capacity of toxic heavy metal ions in liquid phase. Physical and chemical properties of the as-received activated carbon (AC) and two kinds of surface-modified activated carbons (1stAC and 2ndAC) were evaluated through the BET analysis, surface acidity, and oxides measurements. Specific surface area and pore volume did not significantly change, but surface oxide-group remarkably increased by the surface modification. Equilibrium and batch adsorptions of the various metals, such as Pb, Cd, and Cr, using AC, 1stAC, and 2ndAC were performed at initial pH 5. The adsorption capacity and rate of 2ndAC were higher than those of AC and 1stAC. The carboxylic/sodium carboxylate complex groups were developed from the two-step surface modification of activated carbon, which strongly affected the adsorption of metal ions.

In this paper, a study of 2-step damage detection for space truss structures using the extended Kalman filter theory is presented. Space truss structures are composed of many members, so it is difficult to find damaged member from the whole system. Therefore, 2-step damage identification method is applied to detect the damaged members. First, kinetic energy change ratio is used to find damage region including damaged member and then detect damaged member using extended Kalman filtering algorithm in damage region. The effectiveness of proposed method is verified through the numerical examples.

We combined Field-Activated Combustion Synthesis(FACS) with mechanical pressure to produce dense WC-20 vol.%Co composite in one step. The hardness, the fracture toughness and the relative density of the dense WC-20 vol.%Co were investigated. Under the application of 60 MPa pressure and 3000A current on the reactants, the relative density of WC-20 vol.%Co composite was 99.4%. The fracture toughness and hardness were and respectively. The fracture toughness and hardness of WC-20 vol.%Co composite produced by FAPACS were lower than that of nanostructured composite, but similar to commercial ones. Therefore we concluded that the FAPACS method which can produce WC-20 vol.%Co within several minutes in one step is superior to conventional ones.

The recent development of information technology is transforming and redirecting our life into a new one radically different from the past, and such transition in the history of human civilization puts a new meaning on today`s mission of Chinese literacy program in Korea. Now the Chinese literacy education should set up a new set of goals and attempt to improve the methods of teaching and learning in addressing those essential problems including the restoring of the lost ethnicity, the healing of the inveterate social illnesses, and the creative development of the national spirit. Once we are in the age of simultaneous use of Chinese characters in Korea, the teachers of Chinese characters and Literature in highschool should bear in mind the following objectives: First, we should teach the students so that they may help our nation become a strong economy. Second, we should teach the students so that they may have the two Koreas reunified. Third, we should teach the students so that they may better served the tourists from abroad. Fourth, we should teach the students so that they may make our country a local center for knowledge and information. Finally, we should teach the students so that they may help make our spiritual and cultural potential better known to the world. In order to implement the goals in the specific situations, this paper made a survey on the personal opinions of both the teachers and the students and on the possible measures for improvement toward the problems of Chinese literacy education in highschool, and proposed a step-by-step method of teaching Chinese characters and literature for an effective implementation in highschool. As an introductory step dealing with the basic principles, the first step covers the teaching and learning of radicals, of penmanship, of and of reading. As a step for understanding and activating, the second step deals with resources teaching and learning, coinage teaching and learning, mind-map teaching and (earning, NIE(Newspaper in Education) teaching and learning, etc. As a unified level, the third step includes exploration teaching and learning, creative teaching and learning, cooperative teaching and learning, team-teaching methodology, and cyber teaching and learning. Thus the curriculum in highschool will be able to double its educational effect not only on the personal development of the students but also on the national benefits. In the age of simultaneous use of Chinese characters, the teaching of Chinese characters and literature in highschool should search for varied methods and approaches so that we may write a new chapter in which we are able to develop the benefits of our geographical location in the center of the Chinese-character culture zone and to contribute to the prosperity of our nation, the peaceful co-existence of the Far-eastern countries, and the enhanced level of spiritual and cultural awareness of the Globe. For this common purpose all levels of formal education from elementary school to college as well as research institutes should participate in this literacy program with a shared spirit.

본 연구는 철골 건축구조물에 관한 정보의 표현과 교환을 위하여 STEP을 이용한 구조해석 및 설계용 통합 시스템의 모델을 제시한다. 이러한 통합시스템을 구축하기 위하여 철골 구조물 제품모델을 위한 AP 230을 근간으로 기하 및 위상 정보를 나타낼 수 있는 Part 42와 상세한 구조해석을 표현할 수 있는 Part 104을 추가시키고자 한다. 이렇게 함으로서 철골구조물에 관한 종합적인 엔지니어링 정보의 표현을 보다 명확하게 하고 또한 정보의 교환을 보다 쉽게 할 수 있게 된다. 이러한 통합시스템의 개발모델에 따르면 구조물에 관한 상세정보와 시공정보들도 쉽게 추가할 수 있다.

근사단결정 다이아몬드막 성장시 입자의 정렬을 개선하기 위한 집합조직성장의 2단계 성장방법을 제안하였다. 메탄조성 4%, 기판온도 850˚C 조건에서 (100) Si 기판에 - 200V 바이어스를 인가하여 20분동안 전처리 하였다. 처리한 기판을 2%[CH4], 기판온도 810˚C에서 2~35시간동안<100> 집합조직을 지니도록 1단계로 성장시켰다. 이 시편의 성장표면을 평탄화하기 위하여 (100) 면이 성장하도록 2% [CH4], 기판온도 850˚C 조건에서 2단계 성장시켰다. 1단계 성장시간에 따른 다이아몬드막의 배열정도를 111 X-ray pole figure의 반가폭 변화를 통해 관찰하였다. 1단계 성장 후 입자정렬은 막의 두께가 증가할수록 개선되었다. 그러나<100> 집합조직의 표면조직은 피라미드 형태의 굴곡을 피할 수 없었다. 2단계 성장시 (100) 면의 성장으로 인해 막의 표면은 평탄화되었으며, 이때 입자의 정렬은 1단계 성장시간에 크게 의존하였다.

쉘형 구조물의 동적 불안정 문제를 다룬 연구결과는 다소 발표되고 있으나, 위상면을 이용하여 카오스 생성에 관해 기본적 현상을 다룬 연구는 아직 없는 실정이다. 동적 비선형 문제에서, 여러 가지 초기조건에 의해 불안정 현상이 민감하게 발생하는 이유를 파악하기 위해 위상면에서의 끌개의 특성을 조사하여 동적 불안정 생성과정을 검토하는 일은 매우 중요하다. 본 연구에서는 기하학적 비선형을 고려한 얕은 아치의 직접/간접 좌굴을 수치적 기법으로 조사하고, 이를 정적 좌굴하중과 비교한다.

7050 Al합금의 응력부식저항성에 미치는 2단 시효처리의 영향을 미세조직관찰, 전기전도도시험 및 SCF값을 평가함으로써 조사하였다. 최대 경도 이상 과시효에 의해 주 강화상인 η'상이 η상으로 변태되었고, 입내 및 입계에 존재하는 η상의 크기와 간격이 커졌으며 그 결과 응력부식저항성이 증대되었다. 2차 시효시간의 증가에 따라 전기전도도값은 증가되었으나 항복강도의 감소로 인하여 SCF값은 감소되었는데, 이러한 결과는 응력부식저항성의 증가를 의미한다. AMS 4107규격을 기준으로 하였을 때 7050 Al합금 단조재의 적정시효조건은 1차시효가 120˚C에서 6시간, 2차시효는 175˚C에서 12시간이었다.

한려해상국립공원 남해도지구에 위치한 금산의 등산로를 대상으로 하여 등산로에 설치된 계단의 물리적 특성을 조사한 결과, 등산로 총 연장 2,126m 중에 계단이 설치된 구간은 15개 구간이며, 총 길이는 1,000.4m로 나타났다. 대다수의 등산로 계단구역의 물매는 20~40%로 나타났으나, 11번 구간, 12번 구간과 같이 경사도 45.7%, 58.4%의 계단이 268.5m, 188.6m인 구간과 13번 구간과 같이 물매가 67.8%의 급경사 등산로 구간도 설치되어 있었다. 계단형 등산로에서 등산시 탐방객이 느끼는 운동강도를 조사한 결과, 전체 구간에 있어서 등산시의 심박수는 약 104~184회/분으로 나타났으며, 계단형 등산로 구간 중 11번 구간과 12번 구간, 그리고 13번 구간의 등산시 심박수 증가율, 운동강도지수, %HRmax는 각각 166.5%, 89.1%, 92.9%와 167.4%, 89.6%, 93.2%, 그리고 157.8%, 84.5%, 89.9%로 조사되었다.