• Title/Summary/Keyword: core group

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The effect of various sandblasting conditions on surface changes of dental zirconia and shear bond strength between zirconia core and indirect composite resin

  • Su, Naichuan;Yue, Li;Liao, Yunmao;Liu, Wenjia;Zhang, Hai;Li, Xin;Wang, Hang;Shen, Jiefei
    • The Journal of Advanced Prosthodontics
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    • v.7 no.3
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    • pp.214-223
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    • 2015
  • PURPOSE. To measure the surface loss of dental restorative zirconia and the short-term bond strength between an indirect composite resin (ICR) and zirconia ceramic after various sandblasting processes. MATERIALS AND METHODS. Three hundred zirconia bars were randomly divided into 25 groups according to the type of sandblasting performed with pressures of 0.1, 0.2, 0.4 and 0.6 MPa, sandblasting times of 7, 14 and 21 seconds, and alumina powder sizes of 50 and $110{\mu}m$. The control group did not receive sandblasting. The volume loss and height loss on zirconia surface after sandblasting and the shear bond strength (SBS) between the sandblasted zirconia and ICR after 24-h immersion were measured for each group using multivariate analysis of variance (ANOVA) and Least Significance Difference (LSD) test (${\alpha}$=.05). After sandblasting, the failure modes of the ICR/zirconia surfaces were observed using scanning electron microscopy. RESULTS. The volume loss and height loss were increased with higher sandblasting pressure and longer sandblasting treatment, but they decreased with larger powder size. SBS was significantly increased by increasing the sandblasting time from 7 seconds to 14 seconds and from 14 seconds to 21 seconds, as well as increasing the size of alumina powder from $50{\mu}m$ to $110{\mu}m$. SBS was significantly increased from 0.1 MPa to 0.2 MPa according to the size of alumina powder. However, the SBSs were not significantly different with the sandblasting pressure of 0.2, 0.4 and 0.6 MPa. The possibilities of the combination of both adhesive failure and cohesive failure within the ICR were higher with the increases in bonding strength. CONCLUSION. Based on the findings of this study, sandblasting with alumina particles at 0.2 MPa, 21 seconds and the powder size of $110{\mu}m$ is recommended for dental applications to improve the bonding between zirconia core and ICR.

Reframing The Global Leadership Competencies Models (글로벌 리더십 역량 모형의 재구성)

  • Kim, Beom-Seong
    • Journal of Digital Convergence
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    • v.10 no.1
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    • pp.215-228
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    • 2012
  • This study aims to answer the research question of what are the global leadership competencies(GLC) and what is the integrating framework of GLC? To attain the goal of reframing the GLC models with systematic research on GLC, the specific objectives are delineated as follows; the first objective is to identify the area of GLC. The second one is to extract the dimensions agreed with consensus. The third one is to suggest the reframed GLC model. Through the literature review and content analysis about GLC and global mindset, the two dimensions-subject and objects-of GLC model are emerged to classify the existing clusters of GLC. The extracted objects are self, others, culture, business, and global world. The dimension of subject who is global leader is more specifically divided into the knowing/doing process and three aspects of human activity like cognitive, emotional, and behavioral one. GLC are reframed and rearranged based on the two dimensions. As a results new framework for GLC with 11 clusters are presented. Knowing group of GLC contains personal, social, cultural, business literacy, and global mindset. Doing group of GLC contains personal, social, cultural, business savvy, and global change. Personal traits as a core character are at the core of the knowing and doing process of the self. Lastly, the implications and limitations of this research are suggested, and suggestion for further research is followed.

Classification of Shear Strength according to Breccia Content in Fault Core (단층각력 함량에 따른 전단강도의 분류)

  • Yun, Hyun-Seok;Moon, Seong-Woo;Seo, Yong-Seok
    • Economic and Environmental Geology
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    • v.53 no.2
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    • pp.167-181
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    • 2020
  • Analysis of variance (ANOVA) and multiple comparison analysis were performed for shear strengths categorized by breccia content of 5 wt.% (Case-I), 10 wt.%, (Case-II) and 15 wt.% (Case-III) in fault cores. The relationship between breccia contetnt and shear strength was quantitatively classified by calculating the mean and standard deviation of shear strength for each population in each case and then the grouping the breccia contents that had a statistically similar effect on the dispersion of shear strength. As a result, shear strength was clearly classified into group 1 (breccia content of 0-15 wt.%) and group 2 and 3 (breccia coantent of 15-30 wt.% and 30 wt.% or more) in Case-III. Shear strength of the standard line at breccia content of 15 wt.% were determined to be 43.6 kPa, 77.6 kPa, and 118.6 kPa at each normal stress (54 kPa, 108 kPa, and 162 kPa), respectively. In addition, the distribution range of cohesions is 0-43.6 kPa at breccia content of 15 wt.% or less, and 0-70.0 kPa at 15 wt.% or more. Distribution range of friction angles is 0-45.7 ° at breccia content of 15 wt.% or less, and 16.7-57.5 ° at 15 wt.% or more.

Mineral Compositions and Distribution in the Drilling Cores from the Miocene Pohang Basin, Korea (마이오세 포항분지 시추코어의 구성광물과 분포특성)

  • Lee, Jinhyun;Hwang, Jinyeon;Son, Moon;Son, Byeong Seo;Oh, Jiho;Lee, Hyomin
    • Journal of the Mineralogical Society of Korea
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    • v.30 no.3
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    • pp.113-126
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    • 2017
  • In order to investigate the geological storage potential of $CO_2$, X-ray diffraction analysis were conducted for drilling core samples collected from the two drilling sites located in Yonil group of the Miocene Pohang Basin. As a result, various minerals were identified such as quartz, plagioclase, orthoclase opal-CT, smectite, mica, illite, kaolin mineral, chlorite, calcite, gypsum, pyrite, dolomite, and siderite. Smectite was detected in almost all of core samples, and relatively large amounts of smectite were observed in the cores from deeper strata. Opal-CT, mainly occurred in the upper interval of cores, was formed by diagenesis of amorphous diatoms. It shows a tendency that d101 value of cristobalite decreases with depth from $4.10{\AA}$ to $4.05{\AA}$. The almost identical variations in mineral composition with depth are observed at the two sites. This fact indicates that rocks distributed at the two sites were probably deposited in the similar depositional environments. It is determined that the strata in the study area can play roles of cap-rock for $CO_2$ storage, because the considerable amounts of smectite were contained in the rocks through the cores.

Neurobehavioral Change on the Lead Exposure Workers (연 폭로근로자의 신경행동학적 변화)

  • Park, In-Geun;Lee, Duk-Hee;Lee, Yong-Hwan;Kim, Jin-Ha;Jang, She-Han
    • Journal of Preventive Medicine and Public Health
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    • v.28 no.1 s.49
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    • pp.175-185
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    • 1995
  • To evaluate the neurobehavioral effects of blood lead, we performed NCTB (Neurobehavioral Core Test Battery) on 59 men who were exposed to lead occupationally. Performance on the tests was studied in relation to three ranges of blood lead $(low,\;0. Workers with high and medium blood lead concentrations showed poorer performances on digit span backward, digit symbol and Benton Visual Retention. After adjustment for age and education, high and medium group showed significantly impaired performance on Benton visual retention and slightly impaired performance on digit span backward. But it showed no different performance on tests between high and medium blood lead group.

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The Assessment Tools in Palliative Medicine (완화 의학에서의 평가도구)

  • Gwak, Jung-Im;Suh, Sang-Yeon
    • Journal of Hospice and Palliative Care
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    • v.12 no.4
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    • pp.177-193
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    • 2009
  • The assessment of patient status in palliative medicine is essential for determining treatments and for clinical outcomes. The objective of assessment tools is to raise the quality of care for individual patients and their families. There are a number of tools available to assess pain, non-pain symptoms and quality of life. The tools are either uni-dimensional or multi-dimensional measures. Unfortunately, however, no single tool is recommended to be a superior to others in symptoms or quality of life assessment. Therefore, to select an appropriate assessment tool, one should consider the time frame and unique characteristics of tools depending on purpose and setting. The combination of prognostic index is highly recommended in prognostication, and web-based prognostic tools are available. Recently, a new objective prognostic score has been constructed through multicenter study in Korea. It does not include clinicalestimates of survival, but includes new objective prognostic factors, therefore, anyone can easily use it. For beginners in palliative medicine, relatively easy-to-use tools would be convenient. We recommend Eastern Cooperative Oncology Group performance status to assess functional status, numeric rating scale for pain assessment and the Korean version of brief pain inventory for initial pain assessment. Asking directly with numeric rating scale or the Korean version of MD Anderson Symptom Inventory would be desirable to assess various symptoms together. We think that European Organization Research and Treatment Quality of Life Questionnaire Core 15 for Palliative Care is good to assess the quality of life, while Objective Prognostic Score is convenient as prognostic index for beginners.

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Exercise Effect Applied to Patients Who Underwent Lung Resection with Lung Cancer: Systematic Review and Meta-Analysis (폐암으로 폐 절제술을 시행한 환자에게 적용한 운동 효과: 체계적 문헌고찰과 메타분석)

  • Park, Young-Joo;Bae, Phil-Won
    • The Journal of the Korea Contents Association
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    • v.18 no.6
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    • pp.652-666
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    • 2018
  • The purpose of this study was to investigate systematic review and meta-analysisto identify exercise intervention effect applied to patients who underwent lung resection with lung cancer. A total of 1,322 publications were searched from 1990 to 2016 through domestic and foreign electronic databases, and the final 13 publications were selected through literature selection process. Finally, eight RCT (randomized controlled trial) and five NRCT (non-randomized controlled trial) were identified, including 925 participants. The results of the meta-analysis of the effect sizes of the intervention on the outcome variables showed that the health-related quality of life EORTC QOL-C13/30 (the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire) (MD-0.50 95 % CI -0.83-0.18) and SF-36 PCS (the Medical Outcomes 36-Item Short Form Health Survey PCS) (MD 0.75, 95 % CI 0.41-1.10) in the intervention group were significantly higher than the control group. The results of this study suggest that exercise interventions can potentially improve the quality of life of patients who underwent lung resection with lung cancer.

Effect of Porcelain Firing Process on the Marginal and Internal Fit of Ni-Cr Alloy Metal-Ceramic Crown (도재 소성과정이 Ni-Cr 금속도재관의 변연 및 내면 적합도에 미치는 영향)

  • Kim, Ki-Baek;Kim, Seok-Hwan;Kim, Jae-Hong
    • Journal of dental hygiene science
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    • v.14 no.3
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    • pp.405-410
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    • 2014
  • The purpose of this study in vitro investigation was to compare the marginal and internal fit of Ni-Cr alloy metal ceramic crown before and after porcelain veneering. Furthermore, this study evaluated whether the influence of the porcelain firing on the precision of fit of dental prostheses. The maxillary right incisor was selected as an abutment for experiments. Ten working models were prepared. Ni-Cr alloy cores appropriate for each abutment were prepared by lost wax technique. The marginal area and four internal areas of the crowns were measured at two stages: before veneering process and after upper porcelain firing. Silicone replica techniques were used. The data were statistically analyzed with the paired t-test (${\alpha}=0.05$). $Mean{\pm}SD$ marginal and internal gap were $67.1{\pm}23.3{\mu}m$ for the nickle chrome alloy core group and $74.4{\pm}21.9{\mu}m$ for the metal ceramic crown group. There were statistically significant differences in all investigated areas (p<0.05). Within the limitations of this study, none of the Ni-Cr alloy metal crown values measured after porcelain firing process exceeded $120{\mu}m$, which is the clinically acceptable threshold.

A Study on the Revised Draft of Rome Convention on Compensation for Damage Caused by Aircraft to Third Parties - With Respect to the Draft Unlawful Interference Compensation Convention and the Draft General Risks Convention - (항공기에 의하여 발생된 제3자 손해배상에 관한 로마협약 개정안에 대한 고찰 - 불법방해배상협약안과 일반위험협약안을 중심으로 -)

  • Lee, Kang-Bin
    • The Korean Journal of Air & Space Law and Policy
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    • v.22 no.2
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    • pp.27-51
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    • 2007
  • The cumulative result of the work by the ICAO Secretariat, the Secretariat Study Group and the Council Special Group on the Modernization of the Rome Convention of 1952 are two draft Conventions, namely: "Draft Convention on Compensation for Damage Caused by Aircraft to Third Parties, in case of Unlawful Interference", and "Draft Convention on Compensation for Damage Caused by Aircraft to Third Parties" The core provisions of the former draft Convention are as follows: The liability of the operator is strict, that is, without the necessity of proof of fault. It would be liable for damage sustained by third parties on condition only that the damage was caused by an aircraft in flight(Article 3). However, such liability is caped based on the weight of the aircraft(Article 4). It is envisaged to create an independent organization called the Supplementary Compensation Mechanism, with the principle purpose to pay compensation to persons suffering damage in the territory of a State Party, and to provide financial support(Article 8). Compensation shall be paid by the SCM to the extent that the total amount of damages exceeds the Article 4 limits(Article 19). The main issues on the farmer draft Convention are relating to breaking away from Montreal Convention 1999, no limits on individual claims but a global limitation on air carrier liability, insurance coverage, cap of operators' strict liability, and Supplementary Compensation Mechanism. The core provisions of the latter draft Convention are as follows: the liability of the operator is strict, up to a certain threshold tentatively set at 250,000 to 500,000 SDRs. Beyond that, the operator is liable for all damages unless it proves that such damage were not due to its negligence or that the damages were solely due to the negligence of another person(Article 3). The provisions relating to the SCM and compensation thereunder do not operate under this Convention, as the operator is potentially for the full amount of damages caused. The main issues on the latter draft Convention are relating to liability limit of operator, and definition of general risks. In conclusion, we urge ICAO to move forward expeditiously on the draft Convention to establish a third party liability and compensation system that can stand ready to protect both third party victims and the aviation industry before another 9/11-scale event occurs.

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An Efficiency Analysis of Management System for Academy Affairs Process Based on MDA (MDA기반 학사관리 프로세스 유효성 분석)

  • Yoon, Jung-Mo;Kim, Chi-Ho
    • The KIPS Transactions:PartD
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    • v.15D no.2
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    • pp.187-196
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    • 2008
  • The system development approach method of the new paradigm, as being standardizing MDA(Model Driven Architecture) in OMG(Object Management Group), the core technique of MDA definite technique structure for system materialization focusing on Model, is to build the design and the statement for system in PIM(Platform Independent Model), Materialization technique, and to build PSM(Platform Specific Model) adapt to materialization environment, and then to be the technique transforming into language Platform suitable to materialization environment. It includes MOF(Meta-Object Facility), UML, XMI(XML Metadata Interchange), CWM(Common Warehouse Metamodel), the core of MDA. Though these operations MDA support automatic tools product the practicable system after carrying out transform operation with the above information. In this thesis, it will be approached how to design and materialize the Bachelor management system based on MDA and the importance of modeling should be emphasized by applying to the approach method based on MDA. It should be suggested how to develop software efficiently, written it out in PIM, and suggested the process transforming PSM into EJB by J2EE Platform. The system is designed and implemented using automatic tool, edit machine(Together Architect 2006 for Eclipse, Edit plus2) supporting MDA and Database Modeling tool(ER/WIN 4.1). In conclusion, it should be suggested the efficiency analysis result for development process of traditional and based on MDA.