• Title/Summary/Keyword: point defects

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A Study of Automation for Examination Analysis of Inservice Inspection for Nuclear Power Plant (I) (원자력발전소(原子力發電所) 가동중(稼動中) 검사(檢査)의 시험분석(試驗分析)을 위한 자동화연구(自動化硏究) (I))

  • Kim, W.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.5 no.1
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    • pp.34-47
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    • 1985
  • The developing country, KOREA where does not possess the natural resources for traditional energy such as oil and gas, so. The nuclear energy is the most single reliable source available for closing the energy gap. For these reason, It is inavoidable to construct the nuclear power plant and to develop technology related nuclear energy. The rate of operation in large nuclear power facilities depends upon the performance of work system through design and construction, and also the applied technology. Especially, it is the most important element that safety and reliability in operation of nuclear power plant. In view of this aspects, Nuclear power plant is performed severe examinations during preservice and inservice inspection. This study provide an automation of analysis for volumetric examination which is required to nuclear power plant components. It is composed as follows: I. Introduction II. Inservice Inspection of Nuclear Power Plant ${\ast}$ General Requirement. ${\ast}$ Principle and Methods of Ultrasonic Test. ${\ast}$ Study of Flaw Evaluation and Design of Classifying Formula for Flaws. III. Design of Automation for Flaw Evaluation. IV. An Example V. Conclusion In this theory, It is classifying the flaws, the formula of classifying flaws and the design of automation that is the main important point. As motioned the above, Owing to such as automatic design, more time could be allocated to practical test than that of evaluation of defects, Protecting against subjective bias tester by himself and miscalculation by dint of various process of computation. For the more, adopting this method would be used to more retaining for many test data and comparative evaluating during successive inspection intervals. Inspite of limitation for testing method and required application to test components, it provide useful application to flow evaluation for volumetric examination. Owing to the characteristics of nuclear power plant that is highly skill intensive industry and has huze system, the more notice should be concentrated as follows. Establishing rational operation plan, developing various technology, and making the newly designed system for undeveloped sector.

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Spatial Analysis of Flood Rainfall Based on Kriging Technique in Nakdong River Basin (크리깅 기법을 이용한 낙동강 유역 홍수강우의 공간해석 연구)

  • Yoon, Kang-Hoon;Seo, Bong-Chul;Shin, Hyun-Suk
    • Journal of Korea Water Resources Association
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    • v.37 no.3
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    • pp.233-240
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    • 2004
  • Most of hydrological analyses in the field of water resources are launched by gathering and analyzing rainfall data. Several methods have been developed to estimate areal rainfall from point rainfall data and to fill missing or ungaged data. Thiessen and Reciprocal Distance Squared(RDS) methods whose parameters are only dependent on inter-station distance are classical work in hydrology, but these techniques do not provide a continuous representation of the hydrologic process involved. In this study, kriging technique was applied to rainfall analysis in Nakdong river basin in order to complement the defects of these classical methods and to reflect spatial characteristics of regional rainfall. After spatial correlation and semi-variogram analyses were performed to perceive regional rainfall property, kriging analysis was performed to interpolate rainfall data for each grid Thus, these procedures were enable to estimate average rainfall of subbasins. In addition, poor region of rainfall observation was analyzed by spatial interpolation error for each grid and mean error for each subbasin.

Charge Neutral Quasi-Free-Standing Graphene on 6H-SiC(0001) Surface by Pd Silicidation and Intercalation

  • Song, In-Gyeong;Sin, Ha-Cheol;Park, Jong-Yun;An, Jong-Ryeol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.128-128
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    • 2012
  • We investigated the atomic and electronic properties of graphene grown by Pd silicidation and intercalation using LEED, STM, and ARPES. Pd was deposited on the 6H-SiC(0001) surface at RT. The formation of Pd silicide gives rise to breaking of Si-C bonds of the SiC crystal, which enables to release C atoms at low temperature. The C atoms are transformed into graphene from $860^{\circ}C$ according to the LEED patterns as a function of annealing temperature. Even though the graphene spots were observed in the LEED pattern and the Fourier transformed STM images after annealing at $870^{\circ}C$, the topography images showed various superstructures so that graphene is covered with Pd silicide residue. After annealing at $950^{\circ}C$, monolayer graphene was revealed at the surface. The growth of graphene is not limited by surface obstacles such as steps and defects. In addition, we observed that six protrusions consisting of the honeycomb network of graphene has same intensity meaning non-broken AB-symmetry of graphene. The ARPES results in the vicinity of K point showed the non-doped linear ${\pi}$ band structure indicating monolayer graphene decoupled from the SiC substrate electronically. Note that the charge neutrality of graphene grown by Pd silicidation and intercalation was sustained regardless of annealing temperature in contrast with quasi-free- standing graphene induced by H and Au intercalation. Further annealing above $1,000^{\circ}C$ accelerates sublimation of the Pd silicide layer underneath graphene. This results in appearance of the $(6r3x6r3)R30^{\circ}$ structure and dissolution of the ${\pi}$ bands for quasi-free-standing graphene.

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Reconstruction of a long defect of the median nerve with a free nerve conduit flap

  • Campodonico, Andrea;Pangrazi, Pier Paolo;De Francesco, Francesco;Riccio, Michele
    • Archives of Plastic Surgery
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    • v.47 no.2
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    • pp.187-193
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    • 2020
  • Upper limb nerve damage is a common condition, and evidence suggests that functional recovery may be limited following peripheral nerve repair in cases of delayed reconstruction or reconstruction of long nerve defects. A 26-year-old man presented with traumatic injury from a wide, blunt wound of the right forearm caused by broken glass, with soft tissue loss, complete transection of the radial and ulnar arteries, and a large median nerve gap. The patient underwent debridement and subsequent surgery with a microsurgical free radial fasciocutaneous flap to provide a direct blood supply to the hand; the cephalic vein within the flap was employed as a venous vascularized chamber to wrap the sural nerve graft and to repair the wide gap (14 cm) in the median nerve. During the postoperative period, the patient followed an intensive rehabilitation program and was monitored for functional performance over 5 years of follow-up. Our assessment demonstrated skin tropism and sufficient muscle power to act against strong resistance (M5) in the muscles previously affected by paralysis, as well as a good localization of stimuli in the median nerve region and an imperfect recovery of two-point discrimination (S3+). We propose a novel and efficient procedure to repair >10-cm peripheral nerve gap injuries related to upper limb trauma.

Effect of Selenium Doping on the Performance of Flexible Cu2SnS3(CTS) Thin Film Solar Cells (Mo 유연기판을 이용한 Cu2SnS3 박막 태양전지의 셀레늄 도핑 효과)

  • Lee, In Jae;Jo, Eunae;Jang, Jun Sung;Lee, Byeong Hoon;Lee, Dong Min;Kang, Chang Hyun;Moon, Jong Ha
    • Korean Journal of Materials Research
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    • v.30 no.2
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    • pp.68-73
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    • 2020
  • Due to its favorable optical properties, Cu2SnS3 (CTS) is a promising material for thin film solar cells. Doping, which modifies the absorber properties, is one way to improve the conversion efficiency of CTS solar cells. In this work, CTS solar cells with selenium doping were fabricated on a flexible substrate using sputtering method and the effect of doping on the properties of CTS solar cells was investigated. In XRD analysis, a shift in the CTS peaks can be observed due to the doped selenium. XRF analysis confirmed the different ratios of Cu/Sn and (S+Se)/(Cu+Sn) depending on the amount of selenium doping. Selenium doping can help to lower the chemical potential of sulfur. This effectively reduces the point defects of CTS thin films. Overall improved electrical properties were observed in the CTS solar cell with a small amount of selenium doping, and a notable conversion efficiency of 1.02 % was achieved in the CTS solar cell doped with 1 at% of selenium.

Microstructure and Electrical Resistivity of Ink-Jet Printed Nanoparticle Silver Films under Isothermal Annealing (잉크젯 프린팅된 은(Ag) 박막의 등온 열처리에 따른 미세조직과 전기 비저항 특성 평가)

  • Choi, Soo-Hong;Jung, Jung-Kyu;Kim, In-Young;Jung, Hyun-Chul;Joung, Jae-Woo;Joo, Young-Chang
    • Korean Journal of Materials Research
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    • v.17 no.9
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    • pp.453-457
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    • 2007
  • Interest in use of ink-jet printing for pattern-on-demand fabrication of metal interconnects without complicated and wasteful etching process has been on rapid increase. However, ink-jet printing is a wet process and needs an additional thermal treatment such as an annealing process. Since a metal ink is a suspension containing metal nanoparticles and organic capping molecules to prevent aggregation of them, the microstructure of an ink-jet printed metal interconnect 'as dried' can be characterized as a stack of loosely packed nanoparticles. Therefore, during being treated thermally, an inkjet-printed interconnect is likely to evolve a characteristic microstructure, different from that of the conventionally vacuum-deposited metal films. Microstructure characteristics can significantly affect the corresponding electrical and mechanical properties. The characteristics of change in microstructure and electrical resistivity of inkjet-printed silver (Ag) films when annealed isothermally at a temperature between 170 and $240^{\circ}C$ were analyzed. The change in electrical resistivity was described using the first-order exponential decay kinetics. The corresponding activation energy of 0.44 eV was explained in terms of a thermally-activated mechanism, i.e., migration of point defects such as vacancy-oxygen pairs, rather than microstructure evolution such as grain growth or change in porosity.

Electrical Conduction Mechanism in the Insulating TaNx Film (절연성 TaNx 박막의 전기전도 기구)

  • Ryu, Sungyeon;Choi, Byung Joon
    • Korean Journal of Materials Research
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    • v.27 no.1
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    • pp.32-38
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    • 2017
  • Insulating $TaN_x$ films were grown by plasma enhanced atomic layer deposition using butylimido tris dimethylamido tantalum and $N_2+H_2$ mixed gas as metalorganic source and reactance gas, respectively. Crossbar devices having a $Pt/TaN_x/Pt$ stack were fabricated and their electrical properties were examined. The crossbar devices exhibited temperature-dependent nonlinear I (current) - V (voltage) characteristics in the temperature range of 90-300 K. Various electrical conduction mechanisms were adopted to understand the governing electrical conduction mechanism in the device. Among them, the PooleFrenkel emission model, which uses a bulk-limited conduction mechanism, may successfully fit with the I - V characteristics of the devices with 5- and 18-nm-thick $TaN_x$ films. Values of ~0.4 eV of trap energy and ~20 of dielectric constant were extracted from the fitting. These results can be well explained by the amorphous micro-structure and point defects, such as oxygen substitution ($O_N$) and interstitial nitrogen ($N_i$) in the $TaN_x$ films, which were revealed by transmission electron microscopy and UV-Visible spectroscopy. The nonlinear conduction characteristics of $TaN_x$ film can make this film useful as a selector device for a crossbar array of a resistive switching random access memory or a synaptic device.

A family with NKX2.5 gene mutations presenting as familial atrial septal defect and atrioventricular block: A case report

  • Choi, Youn Young;Woo, Min Hyung;Kim, Gi Beom;Song, Mi Kyoung;Lee, Sang Yoon;Bae, Eun Jung;Choi, Murim;Kim, Young-Sook
    • Journal of Genetic Medicine
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    • v.15 no.1
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    • pp.20-23
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    • 2018
  • Point mutations in the human cardiac homeobox gene NKX2.5 are associated with familial atrial septal defect (ASD), atrioventricular (AV) conduction disturbance, as well as sudden cardiac death. To date, more than 60 NKX2.5 mutations have been documented, but there are no reports in Korea. We are reporting the first Korean family with ASD and AV block associated with a novel mutation in the NKX2.5 coding region. A 9-year-old boy presented with a slow and irregular pulse, and was diagnosed with secundum ASD and first degree AV block. The boy's father, who had a history of ASD correction surgery, presented with second degree AV block and atrial fibrillation. The boy's brother was also found to have secundum ASD and first degree AV block. There were two sudden deaths in the family. Genetic testing revealed a novel mutation of NKX2.5 in all affected members of the family.

An Experimental Study on the Flexural Behavior of Pre-loaded RC Beams Strengthened with CFRP-Rod (선하중(先荷重)을 받은 RC보의 CFRP-Rod 휨보강 효과에 대한 실험적 연구)

  • Ye, Sang-Min;Chun, Woo-Chul;Kang, Joo-Won;Park, Sung-Moo
    • Journal of Korean Association for Spatial Structures
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    • v.7 no.1 s.23
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    • pp.79-85
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    • 2007
  • Steel plate bonding method with epoxy is common applied to repair and strengthen RC structures, but Steel is apt to corrode quickly, hard to manufacture and heavy. To overcome these defects, it is carried out research on strengthening RC structures with FRP(Fibre Reinforced Polyrner/Plastic) FRP is generally used in the shape of Plate or Sheet, but it has weak point such as premature failure, difficult work. To cope with these problem, NSMR(Near Surface Mounted Reinforcement) which uses CFRP in the shape of Rod is proposed and carried out active research on strengthening effect of variables such as quantity, anchorage length and space of CFRP-Rod. Strengthening with CFRP-Rod is carried out under loading to some degree in fact, and so the amount of pre-loading is selected as variable in this research. The amount of pre-loading is chosen in proportion to nominal strength of non-strengthened specimen with CFRP-Rod.

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Case study of the large switching software metrics and their fault analysis (대형 교환 소프트웨어의 복잡성과 고장분석 사례 연구)

  • 이재기;남상식;김창봉;이규대
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.10C
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    • pp.887-901
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    • 2002
  • Software management model divided into the software project model and design estimation model, software matrices model, reliability growth model, process improvement model(or process maturity model) etc. Among these software management models, software complexity model make an estimated of the product software. For a practice of software managed, need to guideline of the static analysis of software. Especially, Software complexity model introduced for the estimation of software quantity and program complexity. In case of measurement the software matrices, its need for us to analysis of software quality and products. On the other hand, we known that complexity program include many defects and consuming of source cost. So, we apply to complexity model using of the program complexity, control structure and volume matrices, interface metrics, process complexity metrics method. In this paper, we represent that the analysis of fault data detected during the system test. Also, we analysis of program control structure and interface, volume matrices in various aspect of switching software. Others, their results utilized similar of project and system development.