• 한국생산제조학회지
• /
• 제21권2호
• /
• pp.311-315
• /
• 2012

Diaphragm type noncontact automatic control valve is a valve for controling acidic PR(Photo Resist) liquid used in the semiconductor process. PR is photosensitive liquid that changes phases depending on light transmittance. PR is very toxic and expensive; the purpose of this paper is to address methods that prevent loss due to leaks. The design of noncontact precise automatic control valve is expected to play an important role in controlling fluid flow, therefore influencing energy conservation and environmental improvement. In this paper, diaphragm type automatic control valve's part design, assembly and simulation are introduced. Also, through the analysis of fluid flow the valve's internal velocity, pressure, and turbulent intensity are interpreted. This paper proposes to contribute to the improvement of the valve's performance.

• 한국경영정보학회:학술대회논문집
• /
• 한국경영정보학회 2007년도 International Conference
• /
• pp.539-544
• /
• 2007

People tend to resist changing their software even alternatives are better then the current one. This study examines the resistance to change in the use of software from the switching costs perspective based on status quo bias theory. For this study, we select Web Browsers as software. Based on the classification of switching costs into three groups (psychological, procedural, and loss), this study identifies six types of switching costs (uncertainty, commitment, learning, setup, lost performance, and sunk costs). This study tests the effects of six switching costs on user resistance to change based on the survey of 204 web browser users. The results indicate that lost performance costs and emotional costs have significant effects on user resistance to change. This research contributes towards understanding of switching costs and the effects on user resistance to change. This study also offers suggestions to software vendors for retaining their users and to organizations for managing user resistance in switching and adopting software.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2013년도 추계 학술논문 발표대회
• /
• pp.104-105
• /
• 2013

The buildings constructed with steel structure is coated with certified fire resistive material to resist from fire. Coating materials lose their initial performances as time passes, so they need some maintenance. Fireproof spray-application also loses its performance and this performance loss of thr fireproof spray-application is very important because fire resistance of buildings depends on fireproof spray-application. So this study is to develop Acceleration durability test method of Fireproof spray-application, and use the Certification of fire resistant coating system.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
• /
• pp.51-56
• /
• 2005

It does not find for solution by limitation of technological mechanism of existent of leakage maintenance material. So, it is paid for huge expense because continuous repeat maintenance work is consisting. Furthermore, it is indicated by big problem in construction work that is constructed by field experience that thing by definite and systematic theory is not with proper performance test and analysis up to now. Therefore, wish to measure physical performance change by various environment condition maintenance of structure and performance construction work aspect in that apply to water leakage maintenance material using of acrylic resin system water expansion, leakage maintenance material in this research, and present suitable form of construction work under these environment. also, wish to ready diversified remedy by oversea market opening.

• Steel and Composite Structures
• /
• 제27권6호
• /
• pp.727-745
• /
• 2018

The design criteria and the corresponding performance levels characterize the response of extended stiffened end-plate beam-to-column joints. In order to guarantee a ductile behavior, hierarchy criteria should be adopted to enforce the plastic deformations in the ductile components of the joint. However, the effectiveness of thesecriteria can be impaired if the actual resistance of the end-plate material largely differs from the design value due to the potential activation of brittle failure modes of the bolt rows (e.g., occurrence of failure mode 3 in the place of mode 1 per bolt row). Also the number and the position of bolt rows directly affect the joint response. The presence of a bolt row in the center of the connection does not improve the strength of the joint under both gravity, wind and seismic loading, but it can modify the damage pattern of ductile connections, reducing the gap opening between the end-plate and the column face. On the other hand, the presence of a central bolt row can influence the capacity of the joint to resist the catenary actions developing under a column loss scenario, thus improving the joint robustness. Aiming at investigating the influence of these features on both the cyclic behavior and the response under column loss, a wide range of finite element analyses (FEAs) were performed and the main results are described and discussed in this paper.

• 한국도로학회논문집
• /
• 제19권6호
• /
• pp.129-137
• /
• 2017

PURPOSES : The purpose of this study is to develop bridge deck concrete materials based on ordinary Portland cement concrete, and to evaluate the applicability of the developed materials through material properties tests. METHODS : For field implementation, raw material (cement, fine aggregate, and coarse aggregate) properties, fresh concrete properties (slump and air content), strength (compressive, flexural and bond strength) gain, and durability (freeze-thaw resistance, scaling resistance, and rapid chloride penetrating resistance) performance were evaluated in the laboratory. RESULTS : For the selected binder content of $410kg/m^3$, W/B = 0.42, and S/a = 0.48, the following material performance results were obtained. Considering the capacity of the deck finisher, a minimum slump of 150 mm was required. At least 6 % of air content was obtained to resist freeze-thaw damage. In terms of strength, 51.28 MPa of compressive strength, 7.41 MPa of flexural strength, and 2.56 MPa of bond strength at 28 days after construction were obtained. A total of 94.9 % of the relative dynamic modulus of elasticity after 300 cycles of freeze-thaw resistance testing and $0.0056kg/m^2$ of weight loss in a scaling resistance test were measured. However, in a chloride ion penetration resistance test, the result of 3,356 Coulomb, which exceeds the threshold value of the standard specification (1000 Coulomb at 56 days) was observed. CONCLUSIONS : Instead of using high-performance modified bridge deck materials such as latex or silica fume, we developed an optimum mix design based on ordinary Portland cement concrete. A test construction was carried out at ramp bridge B (bridge length = 111 m) in Gim Jai City. Immediately after the concrete was poured, the curing compound was applied, and then wet mat curing was applied for 28 days. Considering the fact that cracks did not occur during the monitoring period, the applicability of the developed material is considered to be high.

• Structural Engineering and Mechanics
• /
• 제39권6호
• /
• pp.833-847
• /
• 2011

We have developed a lightweight aggregate (LWA) concrete made by expanding fine sediments dredged from the Shihmen Reservoir (Taiwan) with high heat. In this study, the performance of the concrete and of prestressed concrete beams made of the sedimentary LWA were tested and compared with those made of normal-weight concrete (NC). The test results show that the lightweight concrete (LWAC) exhibited comparable time-dependent properties (i.e., compressive strength, elastic modulus, drying shrinkage, and creep) as compared with the NC samples. In addition, the LWAC beams exhibited a smaller percentage of prestress loss compared with the NC beams. Moreover, on average, the LWAC beams could resist loading up to 96% of that of the NC beams, and the experimental strengths were greater than the nominal strengths calculated by the ACI Code method. This investigation thus established that sedimentary LWA can be recommended for structural concrete applications.

• 대한전자공학회논문지SD
• /
• 제41권9호
• /
• pp.73-84
• /
• 2004

본 논문에서는 하드웨어 상에 구현된 암호 프리미티브의 안전성을 위협할 수 있는 부채널 공격의 하나인 단순 전력 분석 (Simple Power Analysis)에 대응하는 알고리즘을 제안하고 이를 하드웨어로 구현하고자 한다. 제시하는 알고리즘은 기존에 알려진 대응 알고리즘보다 스칼라 곱셈 방법이 보다 효율적인 장점이 있다. 기존의 대응 알고리즘은 연산의 종속성 때문에 하드웨어의 장점인 병렬 처리 기법을 효율적으로 적용하기 어려운 단점이 존재한다. 이러한 단점을 보완코자 본 논문에서 제시하는 알고리즘은 동작 성능의 저하를 최소화하기 위해 역원 계산 시간 동안 곱셈 및 제곱 연산을 수행할 수 있도록 구성하였다. 또한 하드웨어 기술 언어인 VHDL(VHSIC Hardware Description Language)로 제안 알고리즘을 구현하여 성능 검증을 수행하였으며 이의 활용을 모색하였다. 하드웨어 합성은 Syplify pro7.0을 사용하였으며, 타겟 칩 Xillinx VirtexE XCV2000EFG1156을 대상으로 하였을 때 전체 등가 게이트는 60,608게이트, 최대 동작 주파수는 약 30Mhz로 산출되었다. 본 논문에서 제시한 스칼라 곱셈기는 전자 서명(Digital Signature), 암호화(Encryption) 및 복호화(Decryption), 키 교환(Key Exchange)등의 핵심 연산으로 사용될 수 있을 것으로 보이며, 자원 제약이 심한 Embedded-Micom 환경에 적용하였을 경우, 단순 전력 분석에 안전하면서 효율적인 연산 기능을 제공할 수 있을 것으로 보인다.

• 공업화학
• /
• 제20권4호
• /
• pp.416-422
• /
• 2009

강구조 건축물은 화재시 화염을 차단하기 위한 목적으로 내화재료를 사용하고 있다. 일반적으로 모든 건축 구조용 재료는 시간이 경과할수록 초기의 성능이 열화되기 때문에 이들의 유지관리가 필요하다. 내화 피복재는 건축물의 화재에 대한 내구성능은 내화피복재에 의존하기 때문에 건축물에서 매우 중요한 재료라 할 수 있다. 본 연구에서는 내화피복재로서의 알칼리 규산염의 합성 및 합성한 알칼리 규산염의 물성에 대해 연구하였는데, 알칼리 규산염의 종류로는 potassium silicate, sodium silicate, lithium silicate으로 하였으며, 기본적으로 몰 비율의 변화를 주어 합성하였다. 합성한 알칼리 규산염의 내화특성을 확인하기 위하여 용해도 포비도, 열 분석, 결정학적 분석, 차열성능 및 차염성능에 대해 시험하였다. 연구결과, 합성한 알칼리 규산염의 용해도, 포비도는 칼륨 실리케이트, 소디움 실리케이트, 리튬실리케이트의 순서로 나타났으며, 열분석에 의한 무게 손실은 소디움 실리케이트와 리튬 실리케이트가 칼륨 실리케이트 보다 큰 것으로 나타났다. 또한 화재 시 가장 중요한 차열성능과 차염성능에 대해KS 기준을 만족하는 것은 소디움 실리케이트 3.3 몰 배합으로 나타났는데, 내화피복재로서 우수한 성능을 발휘하였다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제21권5호
• /
• pp.108-116
• /
• 2017

본 연구는 연쇄붕괴 저항성능 평가 시 기둥의 순간적인 제거에 따른 동적효과가 반영된 에너지 기반 근사해석의 적용성을 확인하기 위해 내진 설계된 철골모멘트골조의 예제구조물을 대상으로 분석하였으며, 이를 통해 구조 강건성을 산정하여 연쇄붕괴에 대한 민감도를 평가할 수 있는 방법을 제시하였다. 예제구조물에 대한 적용을 통해 비선형 정적해석 결과를 이용한 에너지 기반 근사해석과 직접동적해석에 대한 결과가 잘 일치하는 것을 검증하였으며, 다른 구조시스템을 가지는 건물의 연쇄붕괴에 대한 구조적 내력성능을 비교하기 위한 수단으로 구조물의 민감도를 평가하였다. 이는 비정상하중에 대하여 구조물이 연쇄붕괴에 저항할 수 있는 최대보유 잔류내력 성능인 구조 강건성을 이용하였고, 본 연구에서 제시한 방법을 통해 연쇄붕괴 해석 및 설계에 편리하게 활용될 수 있음을 확인하였다.