• Title/Summary/Keyword: cure time

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Curing and Rheological Behavior of Epoxy Resin Compositions for Underfill (언더필용 에폭시 수지 조성물의 경화 및 유변학적 거동)

  • Kim, Yoon-Jin;Park, Min;Kim, Jun-Kyung;Kim, Jin-Mo;Yoon, Ho-Gyu
    • Elastomers and Composites
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    • v.38 no.3
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    • pp.213-226
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    • 2003
  • The cure and rheological behavior of diglycidyl ether of bisphenol F/nadic methyl anhydride resin system with the kinds of imidazole were studied using a differential scanning calorimeter (DSC) and a rotational rheometer. The isothermal traces were employed to analyze cure reaction. The DGEBF/ anhydride conversion profiles showed autocatalyzed reaction characterized by maximum conversion rate at $20{\sim}40 %$ of the reaction. The rate constants ($k_1,\;k_2$) showed temperature dependance, but reaction order did not. The reaction order (m+n) was calculated to be close to 3. There are two reaction mechanisms with the kinds oi catalyst. The gel time was determined by using G'-G" crossover method, and the activation energy was obtained from this results. From measurement of rheological properties it was found that the logarithmic 1:elation time of fused silica filled DBEBF epoxy compounds linearly increased with the content of filler and decreased with temperature. The highly filled epoxy compounds showed typical pseudoplastic behavior, and the viscosity of those decreased with increasing maximum packing ratio.

Characteristics of Dynamic Parameter of Sandy Soil According to Grout Injection Ratio (그라우트 주입율 변화에 따른 사질토의 동적계수 특성)

  • Ahn, Kwangkuk;Park, Junyoung;Oh, Jonggeun;Lee, Jundae;Han, Kihwan
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.5
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    • pp.59-63
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    • 2011
  • Ground dynamic parameter such as shear elastic modulus and damping ratio is a very important variable in design of ground-structure with repeated load and dynamic load. Shear elastic modulus and damping ratio on small strain below linear limit strain is constant regardless of strain. Shear elastic modulus as the maximum shear elastic modulus and damping ratio as the minimum damping ratio were considered. As a lot of experiment related to the maximum shear elastic modulus, which is in dynamic deformation characteristics, have been conducted, many factors including voiding ratio, over consolidation ratio(OCR), confining pressure, geology time, PI, and the number of load cycle affect to dynamic soil characteristic. However, the research of ground dynamic characteristic improved with grout is absent such as underground continuous wall construction, deep mixing method, umbrella arch method. In order to investigate the dynamic soil characteristics improved with grout, in this study, resonant column tests were performed with changing water content(20%, 25%, 30%) and injection ratio of grout(5%, 10%, 15%), cure time(7th day, 28th day) As a result, shear elastic modulus and damping ratio, which are ground dynamic parameter, are affected by the injection ratio of milk grout, cure time and water content.

Analysis on Operation of Anti-Virus Systems with Real-Time Scan and Batch Scan (실시간스캔과 배치스캔을 갖춘 안티바이러스시스템의 운영 분석)

  • Yang, Won Seok;Kim, Tae-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.11
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    • pp.861-869
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    • 2013
  • We consider an information system where viruses arrive according to a Poisson process with rate ${\lambda}$. The information system has two types of anti-virus operation policies including 'real-time scan' and 'batch scan.' In the real-time scan policy, a virus is assumed to be scanned immediately after its arrival. Consequently, the real-time scan policy assumes infinite number of anti-viruses. We assume that the time for scanning and curing a virus follows a general distribution. In the batch scan policy, a system manager operates an anti-virus every deterministic time interval and scan and cure all the viruses remaining in the system simultaneously. In this paper we suggest a probability model for the operation of anti-virus software. We derive a condition under which the operating policy is achieved. Some numerical examples with various cost structure are given to illustrate the results.

A Study on Development of Curing Apparatus for In-place Standard Curing Specimen (현장 표준양생 공시체 관리함의 개발에 관한 연구)

  • 김경민;전충근;손성운;김기철;한천구
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2004.05a
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    • pp.97-100
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    • 2004
  • In-place curing box for specimens is used to cure the compressive strength specimens for control in place concrete. The box if composed of insulating chamber maintaining 20$\pm$3$^{\circ}C$ of temperature, in this paper, strength and temperature history of specimens cured at in plate curing box are investigated to verify field applicability. According to test results, air temperature at measured time shows large temperature variation and below zero, whereas, inside temperature of in place curing box maintains within 20$\pm$3$^{\circ}C$ due to temperature control function. For curing condition. temperature of specimens cured at outside shows large temperature deviation. specimens lured at in-place curing box is not affected by outer temperature.

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Achievements and Challenges of 40th Anniversary Health Insurance (건강보험 40년 성과와 과제)

  • Lee, Kyu Sik
    • Health Policy and Management
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    • v.27 no.2
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    • pp.103-113
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    • 2017
  • There have been many achievements for 40 years since the introduction of compulsory health insurance. Despite many achievements, it has many challenges in health insurance. Aging, non-communicable disease, and low growth economy are threatening the sustainability of health insurance, and it is time to reform the health insurance. A long-term reform plan will be an absolute necessity for reform of health insurance and health care system. Health insurance and health care reform should be an extremely revolutionary content that completely changes the framework. This reform should deal with the philosophy of health, approach of medical education and doctor training, changing supply of medical service, the innovation of primary medical care, reform of public health system, the management of medical utilization, the integration of medical cure and care services, enhancing the benefit coverage, prohibition of covered and non-covered services, etc. Therefore, it is urgent to form a consensus on the necessity of reform, to establish the health insurance plan on this consensus, and to make efforts to make health insurance sustainable.

Curcuma longa: A treasure of medicinal properties

  • Ansar, Saba;Jilani, Shazia;Abbasi, Hana;Siraj, Mantasha binth;Hashimi, Ayshah;Ahmed, Yasmeen;Khatoon, Rizwana;Rifas, AL Mohd.
    • CELLMED
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    • v.10 no.2
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    • pp.9.1-9.7
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    • 2020
  • Nature is full of precious treasure to cure us from various disorders. One of them is Curcuma longa belonging to Zingiberaceae family, present with outstanding therapeutic value and used since time immemorial. Part used from the plant is rhizome native to India (south east continent) which is the world's largest producer, consumer and exporter of turmeric. The active principle called curcumin or diferuloylmethane is a yellow pigment that exhibits numerous activities and wide spectrum of biological actions which include anti-inflammatory, hepatoprotective, anti-cancerous, anti-fungal, neuroprotective activities and many more. This paper focuses on the comparative evaluation of medicinal properties of Curcuma longa as mentioned in Unani classical literature with its modern scientific researches.

Study on a New ACF Bonding Methods in LCD Module Using a High Power Diode Laser (다이오드레이저를 이용한 디스플레이 모듈 내 이방성 전도 필름(ACF) 접합 기술에 관한 연구)

  • Ryu K. H.;Seon M. H.;Nam G. J.;Kwak N. H.
    • Laser Solutions
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    • v.8 no.3
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    • pp.21-26
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    • 2005
  • A bonding process between tape-carrier package and a glass panel with anisotropic conductive film (ACF) has been investigated by making use of high power diode laser as a heat source for cure. The results from modeling of process and from optical properties of layers showed that heat absorbed from polyimide film surface and ACF layer is dominant source of curing during laser illumination. Laser ACF bonding has better bonding quality than conventional bonding in view of peel strength, flatness, pressure unbalance and processing time. New ACF bonding processes by making use of high power diode laser are proposed.

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A Study on the Development of Rolled Dry Floor Heating System for Improving Workability (현장 시공성 개선을 위한 롤타입 건식바닥난방시스템 개발)

  • Lee, Gyu-Dong;Kim, Jun-Ho;Jeong, Chang-Ho;Kim, Dong-Woo;Ogawa, Keiichiro
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.177-180
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    • 2012
  • Korea residential housing generally use wet floor heating system 'Ondol' which consist of insulation cushioning, lightweight foamed concrete, hot water pipe and mortar on top of reinforced concrete slab. Wet floor heating system's installation process is too complicate and difficult to supervise field for continuing assurance quality. Also, this method has a huge impact on the progress of construction because it take a long time to cure finishing mortar and lightweight foamed concrete. Therefore, it is considered a disturbance factor of reduction of construction duration for enhancing competitiveness. In this study, we conducted an experiment about the radiant heat performance and temperature difference on upper panel of rolled dry floor heating systems which is jointly developed by Kolon global and Sumisho Metalex for remodeling housing, studio apartment and the urban-life housing.

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Offsetting a Region Including Islands for Tool-Path Generation (공구 경로 생성을 위한 아일랜드를 포함하는 영역의 오프셋)

  • Park, Sang-Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.12
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    • pp.2009-2018
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    • 2001
  • This paper presents a region offsetting algorithm for tool-path generation. The proposed region offsetting algorithm is developed by expanding the 'PWID offset algorithm [Choi and Park, 1999]'designed to offset a simple polygon. The PWID offset algorithm has three important steps; 1) remove 'local invalid ranges'by invoking a PWID test, 2) construct a raw offset owe and 3) remove 'global invalid ranges'by finding self-intersections of the raw offset cure. To develop a region offsetting algorithm, we modified the PWID offset algorithm by expanding the concept of the 'global invalid range'in the third step. The time complexity of the proposed algorithm is approximately Ο(n), where n is the number of points, and it is free of numerical errors for practical purposes. The proposed algorithm has been implemented and tested with various real regions obtained by intersecting a sculptured surface with a plane.

A study on the global vibration analysis method of the commercial vessels (선박의 전선해석을 위한 모델링 기법에 관한 연구)

  • Cho, Hyun-Dong;Choi, Su-Hyun;Joo, Kyung-Lim
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1153-1159
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    • 2007
  • The vibration analysis is necessary at the design stage to improve crew's life on board and to prevent the vibration troubles of the hull structures and main machineries prior to the construction. Especially, if high vibration problems occur on the global structures like the hull girder and the deckhouse after construction, it takes lots of time, labor and cost to cure them and thus accurate analysis of global vibration should be performed from the design stage. In this study, some factors for the global vibration analysis have been investigated and the way to be applied to the analysis has been suggested.

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