• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.311-318
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• 2018

이 연구에서는, 기둥 횡방향 철근의 화재 후 잔존 역학적 특성 규명 연구의 일환으로, 횡철근비와 기둥의 고온 노출면 수 차이에 따른 횡방향 철근의 손실강도 보상효과를 잔존 압축강도, 변형률 및 탄성계수와 하중-변위 곡선의 상대적 비교분석을 통해 규명하였다. 실험변수로 띠철근의 간격과 고온 노출면 수를 변수로 한 실험체를 제작하여 가열실험을 수행하였다. 이때 전기로 온도를 $400^{\circ}C$, $600^{\circ}C$ 및 $800^{\circ}C$로 설정하여 $13.33^{\circ}C$/분의 속도로 가열하고 2시간동안 그 온도를 유지시켰다. 냉각된 실험체에 대해 응력-변형률 곡선을 구하기 위한 압축실험을 수행하고, 이로부터 탄성계수, 잔존 내력 및 변형률 등의 잔존 역학적 특성을 분석하였다. 실험결과, 고온 노출 면이 많은 기둥이 수열온도 증가에 따라 탄성계수 감소율이 크게 나타나고, 횡철근비가 크면 수열온도 증가에 따라 탄성계수 감소율이 작게 나타났는데, 이로부터 기둥위치와 횡철근비 등이 내화설계나 화재 안전진단 시 고려되어 합리적인 내화성능 평가가 이루어져야 할 것으로 여겨진다.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.366-378
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• 1998

Thermocondensation root canal filling technique have been used to fill accessary canals or to obtain homogeneous root caral fillings. But these thermocondensation technique inevitably produce heat in the canal which can be transmitted through the dentin and cementum and consequently damage periodontal ligamental cells and osteoblasts. In this study, System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$ at $100^{\circ}C$ for 20 seconds. Six weeks later, the dogs were sacrificed and the teeth stained with Hematoxylin and Eosin for histologic examination. 6 extracted human teeth were used to measure the transmitted temperature. After cutting off the crown, the canals were prepared and divided into 3 groups with root thickness of 1.5mm, 1.0mm, 0.5mm, 2 teeth in each group. Inside each root canal, System $B^{TM}$ was heated as with the temperature for the apically condensed and the back filled group, and the transmitted heat was measured on the external surface of the root. The temperature of System $B^{TM}$ heat spreader at $200^{\circ}C$ and $100^{\circ}C$ was also measured at root temperature. It can be concluded as follows: 1. In the thin area (200-$250{\mu}m$) of the root, root resorption could be seen even with heating at $200^{\circ}C$ for 5 seconds. 2. When the spreader was heated at $200^{\circ}C$ for 5 seconds and additionally at $100^{\circ}C$ for 20 seconds for backfill, all teeth showed root resorption regardless of their root thickness. 3. The transmitted external root surface temperature was higher as the root thickness decreased and as the heating time increased. In the thermocompaction technique using System $B^{TM}$, the spreader should be heated for the minimal time and used only in the apical area. The heated spreader shouldn't inserted to the binding point of the canal and backfilling should be done with other means of minimally heated gutta percha technique.

• 원예과학기술지
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• 제33권3호
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• pp.349-355
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• 2015

Lisianthus (Eustoma grandiflorum) is relatively sensitive to temperature and light conditions. For year round production of good quality potted plants and energy saving, it is necessary to understand the growth and flowering response to the combined conditions of these environmental factors. This study was conducted to examine the growth and flowering responses to temperature, photoperiod, and light intensity during the post-seedling stage. 'El Paso Deep Blue' lisianthus plants with four true leaf pairs were grown in growth chambers maintained at average daily temperatures (ADT) of 14, 20, and $26^{\circ}C$ and provided with three photosynthetic photon fluxes [PPF; 100, 200, and $400{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$] for 8 (08:00-16:00) and 16 hours (08:00-24:00) by fluorescent and incandescent lamps, resulting in four daily light integrals (DLI): about 3, 6 (two photoperiods), 12 (two photoperiods), and $24mol{\cdot}m^{-2}{\cdot}d^{-1}$. After treatment for three weeks followed by growth for one week in a greenhouse of $20{\pm}3^{\circ}C$, growth and development were measured. Higher temperature, higher PPF, and longer photoperiod promoted plant growth and flowering; however the impacts of PPF and photoperiod were smaller than those of temperature. As ADT and DLI increased, the number of leaves, number of flowers, lateral shoot length, and shoot dry weight increased. An increase of about $1mol{\cdot}m^{-2}{\cdot}d^{-1}$ DLI could constitute an increase of 0.40 to $0.76^{\circ}C$ ADT depending on these crop characteristics when ADT and DLI are above $20^{\circ}C$ and $12mol{\cdot}m^{-2}{\cdot}d^{-1}$, respectively. Therefore, growers can select a regimen of heating or supplemental lighting without delaying harvesting time or decreasing crop quality.

• Journal of Magnetics
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• 제21권1호
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• pp.35-39
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• 2016

$Cr_{100-x}Ti_x$ amorphous texture-inducing layers (TIL) were investigated to realize highly (002) oriented $L1_0$ FePt-C granular films through hetero-epitaxial growth on the (002) textured bcc-$Cr_{80}Mn_{20}$ seed layer (bcc-SL). As-deposited TILs showed the amorphous phase in Ti content of $30{\leq}x(at%){\leq}75$. Particularly, films with $40{\leq}x{\leq}60$ kept the amorphous phase against the heat treatment over $600^{\circ}C$. It was found that preference of the crystallographic texture for bcc-SLs is directly affected by the structural phase of TILs. (002) crystallographic texture was realized in bcc-SLs deposited on the amorphous TILs ($40{\leq}x{\leq}70$), whereas (110) texture was formed in bcc-SLs overlying on crystalline TILs (x < 30 and x > 70). Correlation between the angular distribution of (002) crystal orientation of bcc-SL evaluated by full width at half maximum of (002) diffraction (FWHM) and a grain diameter of bcc-SL indicated that while the development of the lateral growth for bcc-SL grain reduces FWHM, crystallization of amorphous TILs hinders FWHM. $L1_0$ FePt-C granular films were fabricated under the substrate heating process over $600^{\circ}C$ with having different FWHM of bcc-SL. Hysteresis loops showed that squareness ($M_r/M_s$) of the films increased from 0.87 to 0.95 when FWHM of bcc-SL decreased from $13.7^{\circ}$ to $3.8^{\circ}$. It is suggested that the reduction of (002) FWHM affects to the overlying MgO film as well as FePt-C granular film by means of the hetero-epitaxial growth.

• Structural Engineering and Mechanics
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• 제63권4호
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• pp.497-507
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• 2017

During recent earthquakes, a significant number of concrete structures suffered extensive damage. Conventional reinforced concrete structures are designed for life-time safety that may see permanent inelastic deformation after severe earthquakes. Hence, there is a need to utilize adequate materials that have the ability to tolerate large deformation and get back to their original shape. Super-elastic shape memory alloy (SMA) is a smart material with unique properties, such as the ability to regain undeformed shape by unloading or heating. In this research, four different stories (three, five, seven and nine) of reinforced concrete (RC) buildings have been studied and subjected to near-field ground motions. For each building, two different types of reinforcement detailing are considered, including (1) conventional steel reinforcement (RC frame) and (2) steel-SMA reinforcement (SMA RC frame), with SMA bars being used at plastic zones of beams and steel bars in other regions. Nonlinear time history analyses have been performed by "SeismoStruct" finite element software. The results indicate that the application of SMA materials in plastic hinge regions of the beams lead to reduction of the residual displacement and consequently post-earthquake repairs. In general, it can be said that shape memory alloy materials reduce structural damage and retrofit costs.

• Archives of Reconstructive Microsurgery
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• 제22권1호
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• pp.1-6
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• 2013

Rats and mice are commonly used in experimental laboratories and anesthetic drugs are important for researchers to understand the details. Administration of fluids helps to stabilize the experimental animals before anesthesia via intravenously through the lateral vein in rats and in case of difficulty in catheterization and maintenance, fluids are usually administered as boluses. Large volumes of cool fluids will rapidly lead to hypothermia and all parenteral fluids must be warmed to body temperature before administration. Premedication with a sedative may ease induction with volatile anesthetic drugs. The first choice for rodent anesthesia is complete inhalational anesthesia. The second option is using injectable anesthesia. Recovery from the volatile agents that have been used rapid when the agent is no longer administered. Anesthetic monitoring equipment is an infant-size bell sthethoscope that can be used to ausculate the heart and lungs. Supplemental heating should be provided to reduce the heat loss supply and maintain core body temperature. The kinds of drugs, characteristics, route of administration and care after surgery were reviewed and summarized from the references. Anesthetic drugs, maintenance, monitoring and aftercare are important in the laboratories to keep the animal safe in all experimental procedures.

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1061-1066
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• 1999

The adsorption of CO on W(111) surface in the range of adsorption temperature between 300 K and 1000 K has been studied using AES, LEED, and TDS in an UHV system. After CO saturation at 300 K, four desorption peaks are observed at temperatures (K) of about 400, 850, 1000, and 1100 in thermal desorption spectra, called as α, β1, β2, and β3 state, respectively. The state was attributed to molecular species of CO, which is well known. Because the CO in βstates (especially the β3 state) is still debated as to whether it is dissociative or non-dissociative, the β3 state is mainly discussed. By using the variation method of heating rate in the thermal desorption spectrometry, the desorption energy and pre-exponential factor for the β3 state are evaluated to be 280 kJ/mol and 1.5×10 12 s-1 , respectively. A lateral interaction energy of 5.7 kJ/mol can also be estimated by Bragg-Williams approximation. To interpret the thermal desorption spectra for the β3 state, moreover, those for the model of a first order and a second order desorption are simulated using quasi-chemical approximation. In this study, a model of lying-down CO species is proposed for the β3 state of CO adsorption.

• Structural Engineering and Mechanics
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• 제77권6호
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• pp.819-830
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• 2021

To evaluate the performance of concrete load bearing walls in a structure under horizontal loads after being exposed to real fire, two steps were followed. In the first step, an experimental study was performed on the thermo-mechanical properties of concrete after heating to temperatures of 200-1000℃ with the purpose of determining the residual mechanical properties after cooling. The temperature was increased in line with natural fire curve in an electric furnace. The peak temperature was maintained for a period of 1.5 hour and then allowed to cool gradually in air at room temperature. All specimens were made from calcareous aggregate to be used for determining the residual properties: compressive strength, static and dynamic elasticity modulus by means of UPV test, including the mass loss. The concrete residual compressive strength and elastic modulus values were compared with those calculated from Eurocode and other analytical models from other studies, and were found to be satisfactory. In the second step, experimental analysis results were then implemented into structural numerical analysis to predict the post-fire load-bearing capacity response of the walls under vertical and horizontal loads. The parameters considered in this analysis were the effective height, the thickness of the wall, various support conditions and the residual strength of concrete. The results indicate that fire damage does not significantly affect the lateral capacity and stiffness of reinforced walls for temperature fires up to 400℃.

• Journal of Acupuncture Research
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• 제22권1호
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• pp.109-115
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• 2005

대퇴부 작열감, 동통, 부종을 주소로 내원한 환자 1례를 대상으로 점액낭염에 의한 meralgia paresthetica의 진단 하에 한방적 치료를 시행하여 임상 양상을 관찰한 결과 다음과 같은 결론 을 얻었다. 1. meralgia paresthetica는 포착성 신경병증으로 외측 대퇴 피 신경이 압박되거나 손상되어, 대퇴부 전외측에 감각 저하, 이상 감각 및 작 열감을 호소하는 질환이다. 2. meralgia paresthetica는 한방적으로 '비병(痺病)', '마목(麻木)' 등의 범주에 해당하며 양혈산한통락(養血散寒通絡)의 치법을 활용할 수 있다. 3. 통비(痛痺)와 착휘(着輝)에 해당하는 meralgia paresthetica환자에게 가미활혈탕(加味活血湯) 투여 및 환측(患側)의비관(?關) 복토(伏兎) 충문(衝門) 풍시(風市) 족삼리(足三里) 등의(等) 혈위(穴位)에 자침(刺針)과 습식부항(濕式附缸)을 시술하여 6일만에 현저한 치료 효과를 보았다. 4. 환자는 고관절의 ROM에 있어서 초진시 신전제한 $60^{\circ}$였으나, 5회의 치료 후 신전제한 $0^{\circ}$로 회복되었으며 퇴원시 대퇴부 인통(引痛), 부종(浮腫), 발열(發熱) 등의 증상이 모두 경감되었다.

• 한국진공학회지
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• 제6권3호
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• pp.181-186
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• 1997

TiC(001) 면위에 Mg금속을 증착시킨 후 상온에서 산소를 노출시키는 방법으로 hetero-epitaxial MgO막을 성장시켰으며, 성장된 MgO epitaxial막의 구조를 비행시간형 직 충돌 이온산란분광법을 사용하여 해석하였다. MgO막은 산화 직후 무질서한 배열을 갖으나, 약 $300^{\circ}C$의 가열에 의해서 1$\times$1구조로 전환된다. TiC(001) 위에 성장된 MgO막은 다음과 같은 구조를 갖고 있음이 밝혀졌다. Mg 및 O원자는 TiC의 on-top site에 위치하고, 면내방 향의 격자상수는 TiC의 격자상수와 일치하며, MgO막의 대부분은 2층 이내의 원자층으로 구성되어 있다.