• Title/Summary/Keyword: $K_{IC}$

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Cure Behaviors and Mechanical Interfacial Properties of Epoxy/Polyurethane Blends Initiated by Latent Thermal Catalyst (열잠재성 개시제에 의한 에폭시/폴리우레탄 블렌드의 경화거동 및 파괴인성)

  • Park, Soo-Jin;Seok, Su-Ja;Kang, Jun-Gil;Kwon, Soo-Han
    • Elastomers and Composites
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    • v.39 no.1
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    • pp.42-50
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    • 2004
  • In this work, the diglycidylether of bisphenol A (DGEBA) and modified polyurethane (PU) blends were initiated by N-benzylpyrazinium hexafluoroantimonate (BPH). The cure and fracture toughness of neat DGEBA with the addition of PU were investigated. The cure properties of DGEBA/PU blend system were examined by DSC and near-IR measurements. The fracture touhtness were investigated by measuring the critical stress intensity factor ($K_{IC}$) and the critical strain energy release rate ($G_{IC}$). According to the results, the maximum values of owe activation energy ($E_a$) and conversion (${\alpha}$) were found at 10 phr of PU. Also the $K_{IC}$ showed a similar behavior with the results of conversion. These results were probably due to increase of crosslinking density in the blends resulted from increase of the hydrogen bonding between the hydroxyl groups of DGEBA and isocyanate groups of PU.

Analysis of Research Trends for BrIC Injury (BrIC 상해에 대한 경향 분석 및 고찰)

  • Lee, Kihwang;Kim, Kiseok;Yoon, Ilsung
    • Journal of Auto-vehicle Safety Association
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    • v.8 no.4
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    • pp.12-17
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    • 2016
  • NHTSA (National Highway Traffic Safety Administration) has offered consumers the vehicle safety information on their car since 1978. NHTSA believes that they contribute auto makers to develop safer vehicle for customers, which will result in even lower numbers of deaths and injuries resulting from motor vehicle crashes. NHTSA has been studied why people are still dying in frontal test despite of the use of many restraints system and they understand that current test does not reflect real world crash data such as oblique and corner impact test. As a result, NHTSA announced that a new test method will be introduced to use of enhanced biofidelic dummy and new crash avoidance technology evaluation from 2019. New and refined injury criteria will be applied to Head / Neck / Chest / Lower Leg. BrIC(Brain Injury Criterion)value in NHTSA test results using THOR dummy from 2014 to 2015 was average 0.91 and 1.24 in driver and passenger dummies. IIHS 64kph SOF test is the most likely to new frontal oblique test in an aspect of offset impact which is being studied by NHTSA. In this paper, we focused on head injury, especially brain injury - BrIC and conducted IIHS 64kph SOF (Small Offset Front) test with Hybrid III dummy to evaluate the injury for BrIC. Based on the test results, these data can be predicted BrIC level and US NCAP rating with current vehicle.

IC-CARD TYPE ELECTRONIC MONEY AND IMPROVEMENT POLICY (IC카드헝 전자화폐 도입방안의 문제점과 개선책)

  • 박근수
    • The Journal of Information Technology
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    • v.3 no.1
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    • pp.73-88
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    • 2000
  • Dramatic changes are beginning to occur in plastic card technologies today in the fields of banking, health care, id-cards and more. Advanced card technologies such as IC-card are playing an increasingly important role in new and innovation system. The merit of IC-card are more capacity, more secure, more reliable, quick and easy to update, secure offline processing, enabling technology etc than magnetic stripe card. And so many countries began using experiment of IC- card and our country began October 13 in Cheju island. Then there are three types using-experiment (K-cash, VISA-cash, MONDEX) in Korea. There are some problems such as standards, widely using, high cost, double investment etc. I think that important things in IC-card using is an international- standardizations and issuing corporation.

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Can Induction Chemotherapy before Concurrent Chemoradiation Impact Circumferential Resection Margin Positivity and Survival in Low Rectal Cancers?

  • Bhatti, Abu Bakar Hafeez;Waheed, Anum;Hafeez, Aqsa;Akbar, Ali;Syed, Aamir Ali;Khattak, Shahid;Kazmi, Ather Saeed
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.7
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    • pp.2993-2998
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    • 2015
  • Background: Distance from anal verge and abdominoperineal resection are risk factors for circumferential resection margin (CRM) positivity in rectal cancer. Induction chemotherapy (IC) before concurrent chemoradiation (CRT) has emerged as a new treatment modification. Impact of IC before concurrent CRT on CRM positivity in low rectal cancer remains to be independently studied. The objective of this study was to determine CRM positivity in low rectal cancer, with and without prior IC, and to identify predictors of disease free and overall survival. Materials and Methods: Patients who underwent surgery for rectal cancer between 2005 and 2011 were retrospectively reviewed and divided into two groups. Group 1 received IC before CRT and Group 2 did not. Demographics, clinicopathological variables and CRM status were compared. Actuarial 5 year disease free survival (DFS), overall survival (OS) and independent predictors of survival were determined. Results: Patients in the IC group presented with advanced stage (Stage 3=89.2% versus 75.4%) (P=0.02) but a high rate of total mesorectal excision (TME) (100% versus 93.4%) (P=0.01) and sphincter preservation surgery (54.9 % versus 22.9%) (P=0.001). Patients with low rectal cancer who received IC had a significantly low positive CRM rate (9.2% versus 34%) (P=0.002). Actuarial 5 year DFS in IC and no IC groups were 39% and 43% (P=0.9) and 5 year OS were 70% and 47% (P=0.003). Pathological tumor size [HR: 2.2, CI: 1.1-4.5, P=0.01] and nodal involvement [HR: 2, CI: 1.08-4, P=0.02] were independent predictors of relapse while pathological nodal involvement [HR: 2.6, CI: 1.3-4.9, P=0.003] and IC [HR: 0.7, CI: 0.5-0.9, P=0.02] were independent predictors of death. Conclusions: In low rectal cancer, induction chemotherapy before CRT may significantly decrease CRM positivity and improve 5 year overall survival.

Isolation and Identification of α-Glucosidase Inhibitors from Morus Root Bark (상백피로부터 α-Glucosidase 저해제의 분리 및 동정)

  • Jang, Yeong Jung;Leem, Hyun Hee;Jeon, Yeong Hee;Lee, Dong Hee;Choi, Sang Won
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.44 no.7
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    • pp.1090-1099
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    • 2015
  • Among the four different parts of mulberry (Morus alba L.) tree, ethanol extract of Morus root bark showed the highest ${\alpha}$-glucosidase inhibitory activity ($IC_{50}=12.01{\mu}g/mL$). Bioassay-guided fractionation of the ethanolic extract of root bark by Diaion HP-20, silica gel, ODS-A, and Sephadex LH-20 column chromatographies led to the isolation of four compounds, including Compound (Comp.) 1 ($IC_{50}=5.22{\mu}g/mL$), Comp. 2 ($IC_{50}=1.78{\mu}g/mL$), Comp. 3 ($IC_{50}=2.94{\mu}g/mL$), and Comp. 4 ($IC_{50}=1.54{\mu}g/mL$) with strong ${\alpha}$-glucosidase inhibitory activities. Their chemical structures were elucidated as morusin (Comp. 1), kuwanon H (Comp. 2), chalcomoracin A (Comp. 3), and chalcomoracin B (Comp. 4) by UV and NMR spectral analyses. These results suggest that prenylflavonoid and mulberrofuran of Morus root bark may be useful as potential therapeutic agents for diabetes.

A Study on the Preparation of the Eco-friendly Carbon Fibers-Reinforced Composites

  • Choi, Kyeong-Eun;Seo, Min-Kang
    • Carbon letters
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    • v.14 no.1
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    • pp.58-61
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    • 2013
  • In this work, the effect of catalysts on the mechanical properties of carbon fibers-reinforced epoxy matrix composites cured by cationic latent thermal catalysts, i.e., N-benzylpyrazinium hexafluoroantimonate (BPH) was studied. Differential scanning calorimetry was executed for thermal characterization of the epoxy matrix system. Mechanical interfacial properties of the composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor ($K_{IC}$), and specific fracture energy ($G_{IC}$). As a result, the conversion of neat epoxy matrix cured by BPH was higher than that of one cured by diaminodiphenyl methane (DDM). The ILSS, $K_{IC}$, $G_{IC}$, and impact strength of the composites cured by BPH were also superior to those of the composites cured by DDM. This was probably the consequence of the effect of the substituted benzene group of BPH catalyst, resulting in an increase in the cross-link density and structural stability of the composites studied.

One Package DC/DC Converter for Mobile Phone's Sub-OLED (모바일 폰 외부 OLED용 DC/DC 컨버터 패키지 개발)

  • Oh Se-Wook;Kim Seong-Il
    • Proceedings of the KIPE Conference
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    • 2004.07a
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    • pp.321-324
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    • 2004
  • This paper presents a package IC containing some components of DC/DC converter block for mobile phone's sub OLED(Organic Light Emitting Display). Package IC contains a load switch, a control IC, a diode, a switch for on/off operation, and a switch for changing output voltage. It operates with switching frequency of 100kHz, within the range of input voltage, $3.2V\~5.5V$. Duty ratio can be changed up to $93\%$, and maximum power efficiency is $85\%$. This package IC is loaded onto three model of 1.2W mobile phone's sub-OLED.

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An Ultra-Low Power Expandable 4-bit ALU IC using Adiabatic Dynamic CMOS Logic Circuit Technology

  • Kazukiyo Takahashi;Hashimoto, Shin-ichi;Mitsuru Mizunuma
    • Proceedings of the IEEK Conference
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    • 2000.07b
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    • pp.937-940
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    • 2000
  • This paper describes expandable 4 bit ALU IC using adiabatic and dynamic CMOS circuit technique. It was designed so that the integrated circuit may have the function which is equivalent to HC181 which is CMOS standard logic IC for the comparison, and it was fabricated using a standard 1.2${\mu}$ CMOS process. As the result, the IC has shown that it operates perfectly on all function modes. The power dissipation is 2 order lower than that of HC 181.

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