• Title/Summary/Keyword: Thermal Scale

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Optimal Design of Urban MICROGRID using Economical Analysis Program (경제성분석 프로그램을 이용한 도심형 마이크로그리드 최적 설계)

  • Seung-Duck, Yu;SungWoo, Yim;Youseok, Lim;SungWook, Hwang;JuHak, Lee
    • KEPCO Journal on Electric Power and Energy
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    • v.8 no.2
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    • pp.69-72
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    • 2022
  • This paper actually investigates the load on major large-scale buildings in the downtown area, examines the economic feasibility of installing PV and ESS in a microgrid target building, and evaluates whether an electric vehicle capable of V2G through two buildings is effective as an economical analysis program (HOMER) was analyzed using. It is economical to install a mixture of ESS rather than using the whole PV, and it is shown that if there is an electric vehicle using the V2G function of EV, there is an economic effect to replace the PV. So that Incentives and policies are needed to replace a large area of PV and utilize the existing parking lot to lead EV as a resource of the microgrid. Currently, P2X technology that stores power as ESS or converts it to other energy to control when surplus renewable energy occurs in large-capacity solar power plants and wind farms, etc. This is being applied, and efforts are being made to maintain the stability of the system through the management of surplus power, such as replacing thermal energy through a heat pump. Due to the increase in electric vehicles, which were recognized only as a means of transportation, technologies for using electric vehicles are developing. Accordingly, existing gas stations do not only supply traditional chemical fuels, but electricity, and super stations that also produce electricity have appeared. Super Station is a new concept power plant that can produce and store electricity using solar power, ESS, V2G, and P2G. To take advantage of this, research on an urban microgrid that forms an independent system by tying a large building and several buildings together and supplies power through a super station around the microgrid is in full swing.

The Effect of Transcranial Direct Current Stimulation on Pain and Balance of Total Knee Arthroplasty Patients (경두개직류전류자극이 무릎관절 전치환술 환자의 통증 및 균형 능력에 미치는 영향)

  • Jae-hong, Lee;Dong-ki, Min;Sang-jae, Lee
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.28 no.3
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    • pp.79-87
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    • 2022
  • Background: The purpose of this study was to examine the effect of transcranial direct current stimulation (tDCS) on the pain and balance of patients who receive total knee arthroplasty (TKA). Methods: This study subjects were 24 patients in Hospital T, located in Daegu, South Korea who received TKA after being diagnosed with degenerative arthritis. The subjects were randomly divided into and experimental group and a control group, with each group including 12 patients. Both group received superfical thermal therapy, interferential current therapy (ICT), and continue passive motion (CPM), which are conventional knee therapy on the knee joint. The experimental group received the tDCS treatment three times a week for three weeks, from October 1st to October 20th. The visual analogue scale and Wii Balance Board system were used to measure the pain and balancing ability, respectively, of both groups. In the statistical result analysis, to compare about pre and post test difference in each groups was accomplished. Statistical analysis of independent t-test and paired t-test were conducted using SPSS version 23.0. Results: After three weeks of intervation, there were significantly difference in balance ability in pre and post test in the tDCS group. VAS decreased significantly in both groups(p<.05), There was a significantly difference in pain, balance ability in the tDCS group compared to the sham group. Conclusion: These results indicate that applying tDCS together with conventional knee joint therapy for TKA patients is effective in promoting the patients' recovery.

Frictional Anisotropy of CVD Bi-Layer Graphene Correlated with Surface Corrugated Structures

  • Park, Seonha;Choi, Mingi;Kim, Seokjun;Kim, Songkil
    • Tribology and Lubricants
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    • v.38 no.6
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    • pp.235-240
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    • 2022
  • Atomically-thin 2D nanomaterials can be easily deformed and have surface corrugations which can influence the frictional characteristics of the 2D nanomaterials. Chemical vapor deposition (CVD) graphene can be grown in a wafer scale, which is suitable as a large-area surface coating film. The CVD growth involves cooling process to room temperature, and the thermal expansion coefficients mismatch between graphene and the metallic substrate induces a compressive strain in graphene, resulting in the surface corrugations such as wrinkles and atomic ripples. Such corrugations can induce the friction anisotropy of graphene, and therefore, accurate imaging of the surface corrugation is significant for better understanding about the friction anisotropy of CVD graphene. In this work, the combinatorial analysis using friction force microscopy (FFM) and transverse shear microscopy (TSM) was implemented to unveil the friction anisotropy of CVD bi-layer graphene. The periodic friction anisotropy of the wrinkles was measured following a sinusoidal curve depending on the angles between the wrinkles and the scanning tip, and the two domains were observed to have the different friction signals due to the different directions of the atomic ripples, which was confirmed by the high-resolution FFM and TSM imaging. In addition, we revealed that the atomic ripples can be easily suppressed by ironing the surface during AFM scans with an appropriate normal force. This work demonstrates that the friction anisotropy of CVD bilayer graphene is well-correlated with the corrugated structures and the local friction anisotropy induced by the atomic ripples can be controllably removed by simple AFM scans.

TRAO-TIMES: Investigating Turbulence and Chemistry in Two Star-forming Molecular clouds

  • Yun, Hyeong-Sik;Lee, Jeong-Eun;Choi, Yunhee;Evans, Neal J. II;Offner, Stella S.R.;Baek, Giseon;Lee, Yong-Hee;Choi, Minho;Kang, Hyunwoo;Cho, Jungyeon;Lee, Seokho;Tatematsu, Ken'ichi;Heyer, Mark H.;Gaches, Brandt A.L.;Yang, Yao-Lun
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.37.2-37.2
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    • 2021
  • Turbulence produces the density and velocity fluctuations in molecular clouds, and dense regions within the density fluctuation are the birthplace of stars. Also, turbulence can produce non-thermal pressure against gravity. Thus, turbulence plays a crucial roles in controlling star formation. However, despite many years of study, the detailed relation between turbulence and star formation remain poorly understood. As part of the Taeduk Radio Astronomy Observatory (TRAO) Key Science Program (KSP), "mapping Turbulent properties In star-forming MolEcular clouds down to the Sonic scale (TIMES; PI: Jeong-Eun Lee)", we mapped two star-forming molecular clouds, the Orion A and the ρ Ophiuchus molecular clouds, in six molecular lines (13CO 1-0/C18O 1-0, HCN 1-0/HCO+ 1-0, and CS 2-1/N2H+ 1-0) using the TRAO 14-m telescope. We applied the Principal Component Analysis (PCA) to the observed data in two different ways. The first method is analyzing the variation of line intensities in velocity space to evaluate the velocity power spectrum of underlying turbulence. We investigated the relation between the star formation activities and properties of turbulence. The other method is analyzing the variation of the integrated intensities between the molecular lines to find the characteristic correlation between them. We found that the HCN, HCO+, and CS lines well correlate with each other in the integral shaped filament in the Orion A cloud, while the HCO+ line is anti-correlate with the HCN and CS lines in L1688 of the Ophiuchus cloud.

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A Case of a Patient with Pain & Cold sensation in the Left Upper Segment due to Thrombotic Occlusion of Lt. Brachial Artery (혈전색전증으로 인한 좌상지의 통증 및 냉감을 호소하는 환자 치험 1례)

  • Yang, Jung-yun;Park, Min-jeong;Lee, Mi-rim;Mun, Sang-Kwan;Jung, Woo-sang;Kwon, Seung-won;Cho, Ki-ho
    • The Journal of the Society of Stroke on Korean Medicine
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    • v.18 no.1
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    • pp.23-29
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    • 2017
  • A case of a 47-year-old male patient with Lt.hand pain & cold sensation due to Thrombotic occlusion of Lt. brachial a. is presented. He was treated with acupuncture, electroacupuncture and herbal medicine - 桂枝茯苓丸(Gyejibongnyeong-hwan, Keishibukuryo-gan). We used NRS of pain and Digital Infrared Thermal Image(DITI) to evaluate the progress. After 11days of treatment, there were notable improvement in pain scale, DITI. Korean medical treatment may be effective in treating thrombotic occlusion.

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TRAO KSP TIMES: Homogeneous, High-sensitivity, Multi-transition Spectral Maps toward the Orion A and Ophiuchus Cloud with a High-velocity Resolution.

  • Yun, Hyeong-Sik;Lee, Jeong-Eun;Choi, Yunhee;Evans, Neal J. II;Offner, Stella S.R.;Heyer, Mark H.;Lee, Yong-Hee;Baek, Giseon;Choi, Minho;Kang, Hyunwoo;Cho, Jungyeon;Lee, Seokho;Tatematsu, Ken'ichi;Gaches, Brandt A.L.;Yang, Yao-Lun;Chen, How-Huan;Lee, Youngung;Jung, Jae Hoon;Lee, Changhoon
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.68.1-68.1
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    • 2019
  • Turbulence plays a crucial role in controlling star formation as it produces density fluctuation as well as non-thermal pressure against gravity. Therefore, turbulence controls the mode and tempo of star formation. However, despite a plenty of previous studies, the properties of turbulence remain poorly understood. As part of the Taeduk Radio Astronomy Observatory (TRAO) Key Science Program (KSP), "mapping Turbulent properties In star-forming MolEcular clouds down to the Sonic scale (TIMES; PI: Jeong-Eun Lee)", we mapped the Orion A and the Ophiuchus clouds, in three sets of lines (13CO 1-0/C18O 1-0, HCN 1-0/HCO+ 1-0, and CS 2-1/N2H+ 1-0) with a high-velocity resolution (~0.1 km/s) using the TRAO 14-m telescope. The mean Trms for the observed maps are less than 0.25 K, and all these maps show uniform Trms values throughout the observed area. These homogeneous and high signal-to-noise ratio data provide the best chance to probe the nature of turbulence in two different star-forming clouds, the Orion A and Ophiuchus clouds. We present comparisons between the line intensities of different molecular tracers as well as the results of a Principal Component Analysis (PCA).

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Estimation of Spatial Evapotranspiration Using satellite images and SEBAL Model (위성영상과 SEBAL 모형을 이용한 공간증발산량 산정 연구)

  • Ha, Rim;Shin, Hyung-Jin;Lee, Mi-Seon;Kim, Seong-Joon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3B
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    • pp.233-242
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    • 2010
  • SEBAL (Surface Energy Balance Algorithm for Land) developed by Bastiaanssen (1995) is an image-processing model comprisedof twenty-five sub models that calculates spatial evapotranspiration (ET) and other energy exchanges at the surface. SEBAL uses image data from Landsat or other satellites measuring thermal infrared radiation, visible and near infrared. In this study, the model was applied to Gyeongancheon watershed, the main tributary of Han river Basin. ET was computed on apixel-by-pixel basis from an energy balance using 4 years (2001-2004) Landsat and MODIS images. The scale effect between Landsat (30 m) and MODIS (1 km) was evaluated. The results both from Landsat and MODIS were compared with FAO Penman-Monteith ET. The absolute errors between satellite ETs and Penman-Monteith ET were within 12%. The spatial and temporal characteristics of ET distribution within the watershed were also analyzed.

A Case Study of Buerger's Disease of Soeumin with Lower Extremity Coldness (하지 냉증을 호소하는 소음인 버거씨병 치험 1례)

  • Song Choi;Su-min Jeong;So-eun Son;Jeong-won Byun;Sae-rom Choi;Hye-sun Park
    • The Journal of Internal Korean Medicine
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    • v.44 no.4
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    • pp.741-750
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    • 2023
  • Objectives: This study investigated the effects of Korean medicine treatments on Buerger's disease. Methods: From December 27, 2022, to January 16, 2023, we treated Soeumin patients with Buerger's disease admitted to a hospital specializing in Korean medicine. The patient's symptoms included feelings of coldness in the lower extremities, feelings of dullness, and stabbing pain. For treatment, Korean medicine treatments, such as acupuncture, moxibustion, and herbal medications (Sogyeonghwalhyeol-tang granules and Gwangyebujaijung-tang-gami) were administered. The patient's improvement was evaluated using the numerical rating scale (NRS) every day. Lower extremity and foot temperatures were evaluated using digital infrared thermal imaging (DITI). Results: Through the treatment regimen, the patient's NRS scores decreased, and lower extremity and foot temperatures increased. Conclusions: Korean medicine treatments for cold lower extremities, feelings of dullness, and stabbing pain caused by Buerger's disease are potentially effective.

Characteristics of an electrochromic ECD (electro-chromic device) film in applications for smart windows with a 4-layer structure, a thickness of 0.5 mm (0.5 mm 이내의 두께를 갖는 4층 구조의 스마트 윈도우에 적용되는 전기변색 ECD(electro-chromic device) 필름 제조 및 특성)

  • Nam Il Kim;Geug Tae Kim
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.34 no.1
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    • pp.16-21
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    • 2024
  • Using electrochromic devices (ECD), smart window films that can change the colors from tinted state into transparent state by applying an external voltage were manufactured. Polyethylene terephthalate (PET) film was used as a substrate instead of conventional glass, and ECD modules having a total thickness of about 50 ㎛ were manufactured by sequentially introducing an ITO/Ag/ITO electrode layer, a WO3/TIC2 organic discoloration layer, and a Nafion fluorine electrolyte layer. Through a series of sputtering, bar coating, and thermal compression processes, a large scale smart window with a horizontal and vertical length of more than 80 mm was manufactured. When DC 3.5 V was applied, the transmittance decreased from 54 % to 24 % and moreover the color change could be confirmed even with the naked eye. Reversible color change capability at low external voltage implies that external sunlight can be selectively blocked which is effective in terms of energy saving.

Coupled T-H-M Processes Calculations in KENTEX Facility Used for Validation Test of a HLW Disposal System (고준위 방사성 폐기물 처분 시스템 실증 실험용 KENTEX 장치에서의 열-수리-역학 연동현상 해석)

  • Park Jeong-Hwa;Lee Jae-Owan;Kwon Sang-Ki;Cho Won-Jin
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.4 no.2
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    • pp.117-131
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    • 2006
  • A coupled T-H-M(Thermo-Hydro-Mechanical) analysis was carried out for KENTEX (KAERI Engineering-scale T-H-M Experiment for Engineered Barrier System), which is a facility for validating the coupled T-H-M behavior in the engineered barrier system of the Korean reference HLW(high-level waste) disposal system. The changes of temperature, water saturation, and stress were estimated based on the coupled T-H-M analysis, and the influence of the types of mechanical constitutive material laws was investigated by using elastic model, poroelastic model, and poroelastic-plastic model. The analysis was done using ABAQUS, which is a commercial finite element code for general purposes. From the analysis, it was observed that the temperature in the bentonite increased sharply for a couple of days after heating the heater and then slowly increased to a constant value. The temperatures at all locations were nearly at a steady state after about 37.5 days. In the steady state, the temperature was maintained at $90^{\circ}C$ at the interface between the heater and the bentonite and at about $70^{\circ}C$ at the interface between the bentonite and the confining cylinder. The variation of the water saturation with time in bentonite was almost same independent of the material laws used in the coupled T-H-M processes. By comparing the saturation change of T-H-M and that of H-M(Hydro-Mechanical) processes using elastic and poroelastic material mod31 respectively, it was found that the degree of saturation near the heater from T-H-M calculation was higher than that from the coupled H-M calculation mainly because of the thermal flux, which seemed to speed up the saturation. The stresses in three cases with different material laws were increased with time. By comparing the stress change in H-M calculation using poroelasetic and poroelasetic-plastic model, it was possible to conclude that the influence of saturation on the stress change is higher than the influence of temperature. It is, therefore, recommended to use a material law, which can model the elastic-plastic behavior of buffer, since the coupled T-H-M processes in buffer is affected by the variation of void ratio, thermal expansion, as well as swelling pressure.

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