• Title/Summary/Keyword: Post-Current

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Elasto-Plastic Postbuckling Analysis of Space Truss Structures (공간트러스구조의 탄소성 후좌굴 해석)

  • Lee, Sang-Hwan;Kwun, Ik-No;Kim, Eung-Kyo
    • 한국공간정보시스템학회:학술대회논문집
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    • 2004.05a
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    • pp.37-42
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    • 2004
  • The primary objective of this paper is to trace the post-buckling behavior of space trusses in the inelastic range. Modeled member material behavior characteristics of struts in the post-critical elasto-plastic stage are determined and three types of idealized hardening rules are described. To perform this analysis, the present work is used the current stiffness parameter method combined with the cylinderical arc-length method. Numerical examples are presented to illustrate the accuracy and the application of the numerical solutions introduced above.

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The preparation and Characterization of Bismuth Layered Ferroelectric Thin Films by Sol-Gel Process (솔-젤법을 이용한 Bismuth Layered Structure를 가진 강유전성 박막의 제조 및 특성평가에 관한 연구)

  • 주진경;송석표;김병호
    • Journal of the Korean Ceramic Society
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    • v.35 no.9
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    • pp.945-952
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    • 1998
  • Ferroelectric Sr0.8Bi2.4Ta2O9 stock solutions were prepared by MOD(Metaloganic Decompostion) process. The phase transformation for the layered perovskite of the SBT thin films by changing RTA(Rapid her-mal Annealing) temperatuer from 700$^{\circ}C$to 780$^{\circ}C$ were observed using XRD and SEM. Layered perovskite phase began to appear above 740$^{\circ}C$ and then SBT thin films were annealed at 800$^{\circ}C$ for 1hr for its com-plete crystallization. The specimens showed well shaped hysteresis curves without post annealing that car-ried out after deposition of Pt top electrode. The SBT thin films showed the asymmetric ferroelectric pro-perties. It was confirmed that the properties were caused by interface effect to SBT and electrode by leak-age current density measurement and asymmetric properties reduced by post annealing. At post annealing temperature of 800$^{\circ}C$ remanant polarization values (2Pr) were 6.7 9 ${\mu}$C/cm2 and those of leakage current densities were 3.73${\times}$10-7 1.32${\times}$10-6 A/cm2 at 3, 5V respectively. Also bismuth bonding types of SBT thin film surface were observed by XPS.

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The Effect of Post Oxidation on Corrosion Characteristics of Gas Nitrocarburised Carbon Steels (Nitrocarburising 처리된 탄소강의 내식특성에 미치는 Post Oxidation 효과)

  • Kim, Y.H.;Jung, K.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.12 no.1
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    • pp.9-20
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    • 1999
  • The effect of post oxidation, water-quenched after holding in air for 5~420 seconds or cooling or furnace cooling, on corrosion resistance and phase formation characteristics of the surface layer of SM20C and SM45C carbon steels after gas nirtrocarbursing in the $NH_3-5%CO_2-N_2$ gas atmosphere at $580^{\circ}C$ for 3hours is studied. The compound layers of two steels consist of ${\varepsilon}-Fe_{2-3}N$, ${\gamma}^{\prime}-Fe_4N$ and $Fe_3O_4$, phases, however, the quantity of ${\gamma}^{\prime}-Fe_4N$ phase increases for the furnace cooled specimen compared to that of air cooling specimen. With increasing $NH_3$ content in the gas mixture and also increasing the keeping time in the air after gas nitrocarburising, the ${\varepsilon}-Fe_{2-3}N$ phase of compound layer increases, while the decreased current density recognizing the improvement of corrosion resistance are shown. the passive current density of SM45C steel is lower than that of SM20C steel at the same nitrocarburising conditions.

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Qualitative Content Analysis: Solutions for Tourism Industry to Overcome the Crisis in a Post-Covid 19 era

  • LEE, Soo-Hee
    • The Journal of Industrial Distribution & Business
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    • v.13 no.9
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    • pp.27-36
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    • 2022
  • Purpose: The coronavirus pandemic has affected the tourism industry in a big way. The travel industry suffered intense damage from the pandemic and procedures acquainted to containing its spread because the pandemic outbreak has led to a decline in the number of tourists and a change in their behavior. At this point, this research is to investigate adequate solutions for tourism industry to overcome the crisis in a post-Covid 19 era. Research design, data and methodology: The current author gathered data from each included study to analyze and summarize the evidence when conducting a literature analysis. This stage involves gathering and reviewing intricate texts databases for the meta-analysis. Results: The current author found total five solutions from numerous literature contents, suggesting how to overcome the crisis in a post-Covid era for tourism industry. Solutions as follows, (1) Drawing beginning illustrations, (2) Introducing Government Backing Programs, (3) Increasing Promotion of Tourism Destinations, (4) Enhancing Safety and Security Measures, and (5) Improving Infrastructure and Facilities. Conclusions: This research suggests that although the global economic recession leads to reduced demand and intense competition from other sectors, the tourism industry will be well positioned to weather these challenges if practitioners of tourism organizations follow five solutions of this research.

Failure Examples for Parasitic Current Leakage of Starting System in Automotive (자동차 시동시스템의 암전류 누설에 의한 고장사례연구)

  • Lee, Il-Kwon;Kim, Chung-Kyun;Cho, Seung-Hyun
    • Tribology and Lubricants
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    • v.26 no.5
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    • pp.277-282
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    • 2010
  • The purpose of this paper is to study and analysis the failure examples for parasitic current leakage produced in starting system on gasoline engine. It verified the discharge of battery by electric leakage because of internal wiring damage problem for CD auto changer installed in car. Also, it verified the no-stating phenomenon because of deposit forming by chemical reaction of battery fluid between battery post and cable fixing parts. It verified the damage for brush holder and commutator mixing by internal short phenomenon because of brush carbon a particle and engine oil that was flowed into internal of starting motor. It verified the working phenomenon of audio by a point of contact even if the driver turn to "LOCK" position the key.

On Zinoviev's Homo Sovieticus (지노비요프의 호모 소비에티쿠스론(論) 읽기)

  • Sim, Jieun
    • Cross-Cultural Studies
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    • v.21
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    • pp.87-111
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    • 2010
  • This research examines the concept of 'homo sovieticus' by reviewing the sociological essay novel homo sovieticus written by Zinoviev who was one of the well-known dissident in Soviet Union period, and attempts to have critical understanding of the concept. It is an interesting research topic that current Russia and Russians who get through the historical layers from Soviet to post-Soviet regime at the time current trend that allows to have various academic discussions of post-Soviet. It is required to examine the past of Russia and Russian to make precise estimation of their current and future. Therefore, it is necessary to re-examine the term of 'homo sovieticus' which is conventionally accepted. This research aims at broad comprehension of homo-sovieticus by focusing on the Zinoviev's own understanding instead of the habitual use of the term which only contains ideological and political intention.

A study on the evolution of post-smartphone technologies in the 5G technology environment

  • Kwak, Jeong Ho
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.4
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    • pp.1757-1772
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    • 2020
  • As the smartphone market becomes saturated, an innovative device equipped with new features is expected to appear soon in mobile communications. In particular, various possibilities were raised regarding the alternative technologies that can develop post-smartphones, which are differentiated from the current smartphones, as Korea commercialized the 5G infrastructure for the first time in the world. Under these circumstances, the Korean government announced the "5G+ Strategy for Realizing Innovative Growth" in April 2019, vowing to build an innovative industrial ecosystem quickly while creating various convergence services based on the 5G infrastructure. As described above, the policy importance of the alternative technologies that will develop post-smartphones is increasing, but the theoretical study on the technology evolution of post-smartphones has not been systematically conducted until now. This study reviewed the alternative technologies that can develop post-smartphones through documentary research, and data mining analysis was performed on the research result using actual data. The policy priority was also set quantitatively for the alternative technologies of post-smartphones in order to determine the alternative post-smartphone technology that the government should focus on given the constraint of limited resources. As a results, autonomous vehicle(43.68%) was found to be most important, followed by artificial intelligence(17.4%) and Internet of Things(13.1%), among alternative technologies that could develop into the post-smartphone.

Effects of Neck Stabilizing Exercise Combined with Transcranial Direct Current Stimulation on Muscle Characteristics and Function in Patients with Cervicogenic Headache (경두개 직류자극을 결합한 목 안정화 운동이 경추성두통환자의 근육특성과 기능에 미치는 영향)

  • Park, Seungkyu;Yang, Daejung;Kim, Jeho;Park, Samheon;Yoon, Jonghyuk
    • Journal of The Korean Society of Integrative Medicine
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    • v.7 no.3
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    • pp.159-169
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    • 2019
  • Purpose: The purpose of this study was to provide an effective method of exercise therapy for patients with cervicogenic headache. Methods: The subjects were divided into the following three groups according to the intervention received: cervix-stabilizing exercise (n=12, group 1), transcranial direct current stimulation (n=12, group 2), and cervix-stabilizing exercise combined with transcranial direct current stimulation (n=12, group 3). The intragroup and intergroup differences in muscle characteristics and neck disability index were compared and analyzed. Results: The comparison and analysis of the changes in muscle tone and post hoc analysis revealed statistically significant intragroup decreases in the upper trapezius and suboccipitals in groups I and III, and statistically significant intergroup differences in the upper trapezius, with greater changes in group III than in group II, and in the suboccipitals, with greater changes in groupIII than in groups Iand II. The comparison and analysis of the change in muscle stiffness and post hoc analysis revealed a statistically significanti ntra group decrease in the upper trapezius in group Iand suboccipitals in group III, and a statistically significant intergroup difference in both muscles, with greater change in group III than in group II. The comparison and analysis of change in neck disability index and post hoc analysis revealed a statistically significant intragroup decrease in all the three groups and a statistically significant intergroup difference, with greater change in group III than in groups I and II. Conclusion: The neck-stabilizing exercise and transcranial direct current stimulation were shown to be effective in decreasing the tone of the cervical muscles by stabilizing the cervical bone and improving muscle durability, and in improving the movement and limitation of joint range of motion by decreasing muscle tone and stiffness.

Influence of Interferential Current Therapy and Laser Therapy on Functional Recovery after Total Knee Replacement

  • Oh, Seung-Keun;Kim, Yong-Nam
    • The Journal of Korean Physical Therapy
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    • v.26 no.3
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    • pp.175-181
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    • 2014
  • Purpose: The purpose of this study is to investigate the effects of interference current therapy and laser therapy on functional recovery after total knee arthroplasty by measuring the Berg balance scale and range of motion. Methods: Subjects were 30 patients who were admitted to G Hospital after total knee arthroplasty. They were randomly assigned to experimental group I in which interference current therapy was applied (n=10), experimental group II in which laser therapy was applied (n=10), or the control group (n=10). The Berg balance scale and range of motion of the subjects were measured before, after 2 weeks, and after 4 weeks of therapy. Results: There was a statistically significant change (p<0.05) in the Berg balance scale and range of motion before and after therapy intervention among the laser therapy group and the interference current therapy group. There was also a significant change between the groups in the Berg balance scale and range of motion. Tukey's post hoc comparison showed a statistically significant difference between the control group and experimental group I and between the control group and experimental group II (p<0.05). Conclusion: The application of interference current therapy and laser therapy resulted in a significant change in both the Berg balance scale and range of motion among patients with total knee arthroplasty. The findings of this study can be used as preliminary clinical data in evaluating functional recovery in patients with total knee arthroplasty in a post-clinic setting.

Post-transcriptional Regulation of NK Cell Activation

  • Kim, Tae-Don;Park, Ju-Yeong;Choi, In-Pyo
    • IMMUNE NETWORK
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    • v.9 no.4
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    • pp.115-121
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    • 2009
  • Natural killer (NK) cells play key roles in innate and adaptive immune defenses. NK cell responses are mediated by two major mechanisms: the direct cytolysis of target cells, and immune regulation by production of various cytokines. Many previous reports show that the complex NK cell activation process requires de novo gene expression regulated at both transcriptional and post-transcriptional levels. Specialized un-translated regions (UTR) of mRNAs are the main mechanisms of post-transcriptional regulation. Analysis of posttranscriptional regulation is needed to clearly understand NK cell biology and, furthermore, harness the power of NK cells for therapeutic aims. This review summarizes the current understanding of mRNA metabolism during NK cell activation, focusing primarily on post-transcriptional regulation.