• Title/Summary/Keyword: Repair materials

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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.

Comparison of the fracture resistances of glass fiber mesh- and metal mesh-reinforced maxillary complete denture under dynamic fatigue loading

  • Im, So-Min;Huh, Yoon-Hyuk;Cho, Lee-Ra;Park, Chan-Jin
    • The Journal of Advanced Prosthodontics
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    • v.9 no.1
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    • pp.22-30
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    • 2017
  • PURPOSE. The aim of this study was to investigate the effect of reinforcing materials on the fracture resistances of glass fiber mesh- and Cr-Co metal mesh-reinforced maxillary complete dentures under fatigue loading. MATERIALS AND METHODS. Glass fiber mesh- and Cr-Co mesh-reinforced maxillary complete dentures were fabricated using silicone molds and acrylic resin. A control group was prepared with no reinforcement (n = 15 per group). After fatigue loading was applied using a chewing simulator, fracture resistance was measured by a universal testing machine. The fracture patterns were analyzed and the fractured surfaces were observed by scanning electron microscopy. RESULTS. After cyclic loading, none of the dentures showed cracks or fractures. During fracture resistance testing, all unreinforced dentures experienced complete fracture. The mesh-reinforced dentures primarily showed posterior framework fracture. Deformation of the all-metal framework caused the metal mesh-reinforced denture to exhibit the highest fracture resistance, followed by the glass fiber mesh-reinforced denture (P<.05) and the control group (P<.05). The glass fiber mesh-reinforced denture primarily maintained its original shape with unbroken fibers. River line pattern of the control group, dimples and interdendritic fractures of the metal mesh group, and radial fracture lines of the glass fiber group were observed on the fractured surfaces. CONCLUSION. The glass fiber mesh-reinforced denture exhibits a fracture resistance higher than that of the unreinforced denture, but lower than that of the metal mesh-reinforced denture because of the deformation of the metal mesh. The glass fiber mesh-reinforced denture maintains its shape even after fracture, indicating the possibility of easier repair.

Review on Occupational Exposure To Asbestos in Korea (우리나라 석면 취급 산업장 석면 농도에 대한 고찰)

  • Park, Donguk;Choi, Sangjun;Yoon, Chungsik
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.19 no.3
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    • pp.307-320
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    • 2009
  • This study was conducted not only to review airborne asbestos levels reported in workplaces in Korea, but also to analyze their levels according to various characteristics All asbestos concentration reported as either geometric mean (GM) and geometric standard deviation (GSD) or ranges were transformed to arithmetic mean to estimate exposure level. In addition, weighted arithmetic means (WAMs) were calculated to weigh asbestos levels based on the different number of samples. Differences of asbestos levels among several characteristics such as industry type, decade, operation and sampling and analytical methods were analyzed using analysis of variance (ANOVA). The number of articles studying asbestos levels from workplaces was found to be 9 including two report types. Five of those were reported prior to 1990s and rest of them after 1990s. Only several industries such as asbestos textile, asbestos cement, brake-lining repair shops were studied, while various industries using asbestos or asbestos containing materials (ACMs) were not studied. ANOVA found that asbestos exposure levels (WAM = 5.26f/cc) reported from textile industry were significantly higher than those from other industries (cement = 0.63f/cc, brake-lining = 0.2f/cc - 0.47f/cc) (p < 0.0001). Average exposure levels studied prior to the 1990s (3.13f/cc) were found to be significantly higher than that (0.86f/cc) after the 1990s (p<0.0001). All WAMs reported until the 1994 were found to be higher than the current occupational exposure limits (0.1f/cc). This study recommends that retrospective exposure to asbestos based on various industry types and operations should be assessed.

Effect of surface treatments and universal adhesive application on the microshear bond strength of CAD/CAM materials

  • Sismanoglu, Soner;Gurcan, Aliye Tugce;Yildirim-Bilmez, Zuhal;Turunc-Oguzman, Rana;Gumustas, Burak
    • The Journal of Advanced Prosthodontics
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    • v.12 no.1
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    • pp.22-32
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    • 2020
  • PURPOSE. The aim of this study was to evaluate the microshear bond strength (µSBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols. MATERIALS AND METHODS. Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, µSBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests. RESULTS. The findings revealed that silane application yielded higher µSBS values (P<.05). All surface treatments were showed a significant increase in µSBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05). CONCLUSION. Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases.

Trenchless Repairing-Reinforcing Process of Underground Pipes with Advanced Composite Materials (신소재 복합재료를 이용한 비굴착 지하매설관 보수-보강공법)

  • 진우석;권재욱;이대길;유애권
    • Composites Research
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    • v.15 no.1
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    • pp.21-31
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    • 2002
  • To overcome the disadvantages of conventional excavation technology various trenchless (or excavation free, or no-dig) repair-reinforcement technologies have been developed and tried. But trenchless technologies so far developed have some drawbacks such as high cost and inconvenience of operation. In this study, a repairing-reinforcing process for underground pipes with glass fiber fabric polymer composites using VARTM (Vacuum Assisted Resin Transfer Molding) has been developed. The developed process requires shorter operation time and lower cost with smaller and simpler operating equipments than those of the conventional trenchless technologies. For the reliable operation of the developed method, a simple method to apply pressure and vacuum to the reinforcement was devised and flexible mold technology was tried. Also, resin filling and cure status during RTM process were monitored with a commercial dielectrometry cure monitoring system, LACOMCURE. From the investigation, it has been found that the developed repairing-reinforcing technology with appropriate process variables and on-line cure monitoring has many advantages over conventional methods.

Techniques for Estimating Temper Bead Welding Process by using Temperature Curves of Analytical Solution (해석 해의 온도곡선을 이용한 템퍼비이드 용접공정 평가기술)

  • Lee, Ho-Jin;Lee, Bong-Sang;Park, Kwang-Soo;Byeon, Jin-Gwi;Jung, In-Chul
    • Journal of Welding and Joining
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    • v.28 no.5
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    • pp.51-57
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    • 2010
  • Brittle microstructure created in a heat affected zone (HAZ) during the welding of low alloy steel can be eliminated by post-weld heat treatment (PWHT). If the PWHT is not possible during a repair welding, the controlled bead depositions of multi-pass welding should be applied to obtain tempering effect on the HAZ without PWHT. In order to anticipate and control the tempering effect during the temper bead welding, the definition of temperature curve obtained from the analytical solution was suggested in this research. Because the analytical solution for heat flow is expressed as a mathematical equation of weld parameters, it may be effective in anticipating the effect of each weld parameter on the tempering in HAZ during the successive bead depositions. The reheating effect by the successive bead layer on the brittle coarse grained HAZ formed by earlier bead deposition was estimated by comparing the overlapped distance between the temperature curves in the HAZ. Three layered weld specimens of SA508 base metal with A52 filler were prepared by controlling heat input ratio between layers. The tempering effect anticipated by using the overlapped distance between the temperature curves was verified by measuring the micro-hardness distribution in the HAZ of prepared specimens. The temperature curve obtained from analytical solution was expected as a good tool to find optimal temper bead welding conditions.

Evaluation of Corrosion Resistance using Electro-chemical Methods for the High-Durability Concrete exposed to Marine Condition (해양환경에 노출된 고내구성 콘크리트의 전기화학적기법을 이용한 부식저항성 평가)

  • Yang, Eun-Ik;Kim, Myung-Yu;Lee, Dong-Gun;Han, Sang-Hun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.4
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    • pp.320-328
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    • 2007
  • The durability of marine concrete structures is severely degraded by corrosion due to seawater attack and diffusion of chloride in concrete. The deduction of durability causes high repair cost for maintenance of marine concrete structure. So, the applicability of high-durable materials is investigated to improve the durability in marine concrete structures. For these, the characteristics of corrosion prevention of marine concrete structures mixed with the mineral admixtures(SF, FA and BFS), the modified steel(stainless and coating steel), and corrosion inhibitors are evaluated using electro-chemical methods. As a results of this study, it is quantified for the effect of promotion of durability by high-durability materials in marine concrete structures.

CLINICAL EVALUATION OF CORALLINE BASED POROUS HYDROXYAPATITE AND CORALLINE BASED CALCIUM CARBONATE IN HUMAN INTRABONY PERIODONTAL LESIONS (Coralline Based Porous Hydroxyapatite와 Coralline Based Calcium Carbonate의 이식후 치조골내결손부에 대한 임상적 평가)

  • Shim, Jung-Min;Son, Seong-Heui;Han, Soo-Boo
    • Journal of Periodontal and Implant Science
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    • v.24 no.1
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    • pp.120-130
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    • 1994
  • The purpose of the present investigation was to compare the effectiveness of porous hydroxyapatite (PHA) and coralline based porous calcium carbonate(PCC) as implant materials in human periodontal osseous defects. 10 adult patients having periodontitis and 2 similar angular osseous defects ${\ge}$5mm as verified by radiographic analysis and clinical probing depth ${\ge}$4mm were selected. The measurements were recorded just before surgery and after 6 month. Clinical parameters used in this study included gingival recession, pocket depth, probing attachment level, Sulcus Bleeding Index, Plaque Index, tooth mobility and bone defect depth measurements. After initial therapy, patients were treated with mucoperiosteal flap surgery. The contralateral bony defects in each patient randomly assigned to either bone graft material, one with PHA(Interpore 200) and the other with coralline based calcium carbonate(Biocoral). After 6 month both groups showed statistically significant reduction of pocket depth, Sulcus Bleeding Index, Plaque Index and significant improvement in probing attachment level. No statistically significant differences were found between the groups. There were 3.0mm or 68% of bone repair with PHA and 3.1mm, 61% with PCC. These values were likewise not significantly different. The data and clinical impression strongly suggest that both PHA and PCC are alloplastic implants with clinically apparent acceptance by the soft and hard tissue and that they can be used as bone graft materials successfully.

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The Conservation Treatment for the Important Folklore Materials-Clothes (중요민속자료(복식)의 보존처리)

  • Han, Sung-Hee;Lee, Kyu-Shik
    • 보존과학연구
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    • s.14
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    • pp.94-108
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    • 1993
  • The cultural properties of cloth are of animal orgin (silk), or of vegetable orgin(cotton, hemp, ramie). As clothes are of an orginic material, they were subjected to damage by chemical, phisigical or biological factors, viz, moulds insects, lights, humidity and temperature changes, etc. And these factors promote that clothes generally result from various types of deterioration. In 1992, We were performed the conservation treatments for total 9 pieces of cloth, such as 3 pieces of General PAK SHIN-RYONG(Important Folklore Material No.110) 3 pieces of Madam Jung(Important Folklore Material No.115) and 1 piece of King Se-jo(Important Folklore Material No.219). The procedure of the conservation treatment for clothes describe the following below. 1) The washing and dry-cleaning to remove the contaminated substances from cloth was used 0.2% stearyl potassium soap solution and the mixture solution compound of n-Hexane, C6H14. and n-Decane, C10H22. And after the washing and dry-cleaning, the dry of clothes was carried out in a warm condition. These steps were repeated in 2 times over for each cloth. 2) The repair of clothes was attached the similar textiles to stronger fabric linings by needlework.3) The reprodution was made for cloth of King Se-jo to equalize the type, color, quality and skill of materials. 4) After these above procedures, all clothes fumigated to prevent the biodeterioration by using the mixed gas of methyl bromide and ethylene oxide as insecticide and fungicide. 5) Finally for the purpose to keep in a safety long-term condition, the treated clothes sealed with Biaxially Oriented Polyvinylacohol Film(BO-PVA film) and Helium, purity 99.999%, filled up in sealed BO-PVA film bag.

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Integrity test and depth estimation of deep foundations (깊은 기초의 건전도시험과 근입깊이 조사)

  • Jo Churl-hyun;Jung Hyun-key;Lee Tai-sup;Kim Hag-soo
    • 한국지구물리탐사학회:학술대회논문집
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    • 1999.08a
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    • pp.202-216
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    • 1999
  • The deep foundation is frequently used for the infrastructures. Since the quality control of the cast-in-place concrete foundations such as CIP piles and slurry walls is not so easy as that of the ready made PC(prestressed concrete) piles, it is necessary to get the information on the integrity of the concrete of the foundation. The depth estimation of foundations whose depths are unknown is also very important in repair and reinforcement works or in safety inspection and assessment to the big structures. The cross-hole sonic logging(CSL) system and the single channel reflection seismic measurement system were developed to test the integrity of pile. The former is well applied to CIP structures, while the later to all kinds of piles with less accurate result compared to that of CSL. To estimate the depth of the deep foundations, parallel seismics, borehole RADAR, and borehole magnetics can be used.

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