• Title/Summary/Keyword: Self-repair

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A Fundamental Study on the Influence of Performance of Cementitious Composites of Inorganic Core Material for Self-Healing Capsule of Cracks (균열 자기치유를 위한 캡슐용 무기계 코어재료의 시멘트 복합체 성능에 미치는 영향에 관한 기초적 연구)

  • Choi, Yun-Wang;Oh, Sung-Rok;Choi, Byung-Keol;Kim, Cheol-Gyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.1
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    • pp.74-82
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    • 2017
  • In this study, we prepared a core material based on the inorganic materials in liquid form for applying an inorganic-based core material to a core material for the self-healing capsules as a part of the basic study to manufacture of self-healing capsule that can heal cracks of cementitious composite. Manufactured core material based on the inorganic materials were applied directly to the cement composite before its encapsulation, were evaluated the effect on performance of cementitious composite as wall as repair performance of the cracks in the cracks. The test results showed that core material based on the inorganic materials was effective to improve the compressive and adhesion strength, had an absorption, permeation water, penetration of chloride iones and freeze-thaw resistance performance. Through the results of this paper, we want to utilize the results as a basis data of the performance of the cement composite that can be obtained when applied to inorganic core materials based on self-healing capsules and future advances localized self-healing capsule technology.

3-D Hetero-Integration Technologies for Multifunctional Convergence Systems

  • Lee, Kang-Wook
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.2
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    • pp.11-19
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    • 2015
  • Since CMOS device scaling has stalled, three-dimensional (3-D) integration allows extending Moore's law to ever high density, higher functionality, higher performance, and more diversed materials and devices to be integrated with lower cost. 3-D integration has many benefits such as increased multi-functionality, increased performance, increased data bandwidth, reduced power, small form factor, reduced packaging volume, because it vertically stacks multiple materials, technologies, and functional components such as processor, memory, sensors, logic, analog, and power ICs into one stacked chip. Anticipated applications start with memory, handheld devices, and high-performance computers and especially extend to multifunctional convengence systems such as cloud networking for internet of things, exascale computing for big data server, electrical vehicle system for future automotive, radioactivity safety system, energy harvesting system and, wireless implantable medical system by flexible heterogeneous integrations involving CMOS, MEMS, sensors and photonic circuits. However, heterogeneous integration of different functional devices has many technical challenges owing to various types of size, thickness, and substrate of different functional devices, because they were fabricated by different technologies. This paper describes new 3-D heterogeneous integration technologies of chip self-assembling stacking and 3-D heterogeneous opto-electronics integration, backside TSV fabrication developed by Tohoku University for multifunctional convergence systems. The paper introduce a high speed sensing, highly parallel processing image sensor system comprising a 3-D stacked image sensor with extremely fast signal sensing and processing speed and a 3-D stacked microprocessor with a self-test and self-repair function for autonomous driving assist fabricated by 3-D heterogeneous integration technologies.

Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material

  • Erdemir, Ugur;Sancakli, Hande Sar;Sancakli, Erkan;Eren, Meltem Mert;Ozel, Sevda;Yucel, Taner;Yildiz, Esra
    • The Journal of Advanced Prosthodontics
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    • v.6 no.6
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    • pp.434-443
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    • 2014
  • PURPOSE. The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS. A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of $6mm{\times}4mm$ and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with $30{\mu}m$ silica oxide particles ($Cojet^{TM}$ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at ${\alpha}=.05$. RESULTS. Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001). CONCLUSION. Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.

Replantation of the Amputated Penis using Microsurgery (미세수술에 의한 절단 음경의 재접합)

  • Kang, Yang-Soo;Park, Yong-Nam;Lee, Myung-Ju;Yang, Jeong-Yeol;Rho, Joon;Kim, Chul-Sung
    • Archives of Reconstructive Microsurgery
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    • v.10 no.1
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    • pp.23-27
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    • 2001
  • Penile amputation results primarily from attempts at self-emasculation in the psychotic individual or from felonious assault. Because of the complex nature of patients whom perform self-emasculation and low incidence of felonious assault, large series of these individuals do not exist, and experience with amputation injuries of the genitals is confined to individual case reports. Fortunately, complete amputation of penis is quite rare but potentially devastating occurrence. The repels of the treatment of penile amputation by coporal reapproximation that have been published since 1977 indicate that microreplantation techniques are propably superior to the technically simpler nonmicroscopic coporal reapproximation techniques. As microsurgical techniques have been demonstrated to superior, the preferred method of replantation involves this routine whenever possible. We have experience of a case of successful replantation of completely amputated penis by using microneurovascular repair, with the good result of cosmetic and functional concern. Herein, we report this case with the review of the literatures.

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Functional properties of the thermostable mutL from Thermotoga maritima

  • Kim, Tae-Gyun;Heo, Seong-Dal;Ku, Ja-Kang;Ban, Chang-Ill
    • BMB Reports
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    • v.42 no.1
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    • pp.53-58
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    • 2009
  • The methyl-directed mismatch repair (MMR) mechanism has been extensively studied in vitro and in vivo, but one of the difficulties in determining the biological relationships between the MMR-related proteins is the tendency of MutL to self-aggregate. The properties of a stable MutL homologue were investigated using a thermostable MutL (TmL) from Thermotoga maritima MSB8 and whose size exclusion chromatographic and crosslinking analyses were compatible with a dimeric form of TmL. TmL underwent conformational changes in the presence of nucleotides and single-stranded DNA (ssDNA) with ATP binding not requiring ssDNA binding activity of TmL, while ADPnP-stimulated TmL showed a high ssDNA binding affinity. Finally, TmL interacted with the T. maritima MutS (TmS), increasing the affinity of TmS to mismatched DNA base pairs and suggesting that the role of TmL in the formation of a mismatched DNA-TmS complex may be a pivotal observation for the study of the initial MMR system.

Evaluation of Fracture Detection Function for the Concrete by Self-Diagnosis CPGFRP (자기진단 CPGFRP의 파괴예측기능 평가를 위한 콘크리트 적용실험)

  • Choi, Hyun-Soo;Park, Jin-Sub;Jnng, Min-Soo;Kang, Byeung-Hee
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.11a
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    • pp.27-31
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    • 2003
  • To maintain serviceability of concrete structure more than proper it is necessary not only predict service life through periodical monitor but also need monitoring system to recognize optimal time and method for repair. Recently, CPGFRP, replacing some GFRP with CF, is developed and used for monitoring concrete fraction. But dramatic resistance change of CPGFRP is showed below 0.5% strain and it is not small strain in terms of monitoring micro crack in concrete. In other word, monitoring with CF is not suitable in low stress hut hight stress. In this study, we accessed applicable possibility and reliability of CPGFRP composite as monitoring sense that is proved very sensitive to stress through domestic and oversea previous study. CPGFRP composite plays a role in specimen like steel and increases flexural strength. CPGFRP composite shows resistance increasement in micro crack. In particular, CPUFRP is more sensitive than strangage in low stress. Resistance change ratio curve is very similar to strain curve so sensitivity and reliability is very excellent to monitor concrete fracture.

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Evaluation of Fracture Detection Function for the Concrete by Self-Diagnosis CPGFRP (자기진단 CPGFRP의 파괴예측기능 평가를 위한 콘크리트 적용실험)

  • 최현수;박진섭;정민수;강병희
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.27-31
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    • 2003
  • To maintain serviceability of concrete structure more than proper it is necessary not only predict service life through periodical monitor but also need monitoring system to recognize optimal time and method for repair. Recently, CPGFRP, replacing some GFRP with CF, is developed and used for monitoring concrete fraction. But dramatic resistance change of CPGFRP is showed below 0.5% strain and it is not small strain in terms of monitoring micro crack in concrete. In other word, monitoring with CF is not suitable in low stress but hight stress. In this study, we accessed applicable possibility and reliability of CPGFRP composite as monitoring sense that is proved very sensitive to stress through domestic and oversea previous study. CPGFRP composite plays a role in specimen like steel and increases flexural strength. CPGFRP composite shows resistance increasement in micro crack. In particular, CPGFRP is more sensitive than strangage in low stress. Resistance change ratio curve is very similar to strain curve so sensitivity and reliability is very excellent to monitor concrete fracture.

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AN EXPERIMENTAL STUDY ON PULPAL RESPONSE TO THE SELP-CURING RESIN FOR THE DIFFERENCE OF MIXING TIMES IN CAT (상온중합(常溫重合) 레진의 혼합시간(混合時間) 차이(差異)에 따른 성묘(成描)의 치수(齒髓反應)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Lee, Hyun-Shick;Woo, Y.H.;Park, Nam-Soo
    • The Journal of Korean Academy of Prosthodontics
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    • v.27 no.1
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    • pp.213-222
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    • 1989
  • It is considered that self-curing resin will induce a little pulpal irritation, if mixing time is insufficient. So this study was designed to compare four different conditions between control group and three experimental groups. Canine teeth of 20 cats used, and class V cavities were prepared on maxillary canine of cats. Control group was filled with zone and other experimental groups were filled with zone after the application of the self-curing resin. Animals of the experimental and control group were sacrified at 3 days, 1, 2, 3, 4 weeks after the experiment. The finding lead to the following conclusions ; 1. Odontoblasts of first and third experimental groups were condensed irregularly and were changed at early stage, and reapir was delayed. 2. Odontoblasts of second experimental group were condensed slightly but, histologic repair was appeared at 4 weeks after the experiment 3. In all groups, the damaged odontoblastic cell layer were eventually disappeared at 4 weeks after the experiment.

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Application of Eco-hydraulics Principles in Rehabilitation of Urban River System

  • Meiyan, Feng;Jung, Kwansue
    • Proceedings of the Korea Water Resources Association Conference
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    • 2018.05a
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    • pp.446-446
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    • 2018
  • The urban rivers have unique hydraulic characteristics between natural rivers and artificial canals. These hydraulic characteristics determine the characteristics of urban rivers with small environmental capacity and fragile ecosystems. With the development and utilization of natural resources, the pollutants that have been produced enter the river through different channels, which seriously damages the urban river ecosystem. Therefore, how to restore contaminated water to a normal state and reproduce a natural, self-regulating ecosystem is one of the most concerned issues in recently. Eco-hydraulics is a cross-disciplinary subject of hydraulics biology and ecology. It is closely related to the protection of rivers, wetlands, and ecological self-repair. In this study, The basic principle of eco-hydraulics is concisely described and its approaches to protection and rehabilitation of river are introduced. The conception of establishing gardenesque eco-pond for urban use is suggested. The strategies including changing the hydrodynamic features of rivers, adjusting the breeds and species and constructing the gardenesque eco-pond for improving the exist ing urban rivers are proposed. It provides scientific information and guidance for the restoration of rivers and wetlands by studying the close relationship between river hydraulic characteristics, currents, and rivers and ecosystems.

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Polymerization Behavior of Self-healing Agents for Damage Repair in Composite Materials (복합재 손상보수용 자가치료제의 중합 거동)

  • Oh, Jinoh;Yoon, Sungho;Jang, Seyong
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.5
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    • pp.35-42
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    • 2014
  • Thermal analysis properties and adhesive properties of self-healing agents were evaluated through differential scanning calorimetry, reaction heat measurement, and adhesive shear test. D1E0, D3E1, D1E1, D1E3, and D0E1, depending on the mixing ratio of DCPD and ENB, were considered as self-healing agents. The amount of Grubbs' catalyst, depending on the type of self-healing agents, was varied from 0.1 wt% to 1.5 wt%. In the case of DCPD, the polymerization reaction occurred faster and the stabilized adhesive strength increased as the amount of catalyst increased; however, a large amount of catalyst was required. ENB had excellent reactivity with a small amount of the catalyst; however, high reaction heat was observed at the early stage of polymerization. Thermal analysis properties and adhesive properties of self-healing agents can be controlled by varying a mixing ratio of DCPD and ENB. Among the self-healing agents used for this study, the D3E1 would be one of the most preferable candidates with regard to maximum adhesive strength, reaching time to maximum adhesive strength, stabilized adhesive strength, and reaction heat.