• 한국구조물진단유지관리공학회 논문집
• /
• 제19권6호
• /
• pp.63-71
• /
• 2015

본 연구는 섬유를 혼입한 고강도 콘크리트의 온도 변화에 따른 내화특성 분석에 관한 연구로 고강도 콘크리트에 고온이 가해질 경우 발생되는 폭렬현상에 대하여 방지효과가 있는 것으로 알려져 있는 하이브리드섬유와 강섬유를 함께 혼입하여 만든 복합섬유를 사용하여 온도 변화($100{\sim}800^{\circ}C$)에 따른 고강도 콘크리트의 내화특성 및 역학적 메커니즘을 분석하였다. 또한 본 논문에서는 고강도 콘크리트 구조물에서 가장 문제가 되는 폭렬현상을 막는 대책 중의 하나인 섬유 혼입을 통한 방법을 사용하여 SEM 및 XRD 분석 등의 방법으로 고온을 받은 고강도 콘크리트의 열적 특성 및 역학적 특성을 규명하고자 하였다.

• 대한기계학회논문집B
• /
• 제24권5호
• /
• pp.632-639
• /
• 2000

Conjugate heat transfer from a heat generating module ($31{\times}31{\times}7mm^3$) bonded through the module support on the floor of a parallel-plate channel(20mm high, 400mm wide, and 800mm long) to mixed convective air flow(0.2${\sim}$0.9m/s) is studied experimentally. The input power to the module is changed in a range 1.0${\sim}$4.5W, the floor thickness 0.2${\sim}$5mm, and the thermal resistance of module support, Rc:=0.06, 1.03 and 82.0K/W. Thermal conductance(Uc) of the board and convective thermal conductance($U_A$) from the module were derived, and the effect of V; Rc and t on Uc was investigated. It is found that the conjugate conductance (Uc) and the conductive heat transfer ratio ($Q_B$/Q) depend on the thermal resistance of the module support, the air velocity and the board thickness. The change of the module support resistance and the board thickness helps to elucidate the relative significance of heat transfer paths through the module support, the board, and from the board surface to the air. Additional information is investigated about the dependence of the heat transfer rate on the mixed convection parameter.

• Journal of Plant Biology
• /
• 제5권3호
• /
• pp.11-20
• /
• 1962

본실험에서는 Gibberellin 이 여섯작물의 생육 및 그들의 성장에 미치는 토양재배를 과하여 조사하였다. 식물 잎에 살포한 Gibberellins의 비교적 적은 농도차는 식물의 생육 및 내부 성분에 현저한 차이를 가져오는 것을 알 수 있다. 농도가 높아짐에 따라 작물의 생육은 촉진되고 그 생육간의 차이는 유의하였다. 여섯 작물의 Chlorophyll 및 Corotene 함량은 Gibberellin의 농도에 비례하여 감소 되었으며 이는 생장율과 크게 상반되었다. 여섯 작물의 Vitamin C의 함량은 Gibberellin의 농도에 비례하여 감소되었다. 이 차는 무, 쑥갓 및 시금치에서 높은 유의성을 나타냈다. Chlorophyll과 Vitamin C의 함량은 발육이 진전 됨에 따라 달라지는데 이 차이는 유의한 것이다. Corotene 함량은 Chlorophyll 량과 함께 변하였는데 Carotene과 Chlorophyll의 비는 Beck 및 Redman이 얻은 결과처럼 높은 것은 아니다.

• 사상체질의학회지
• /
• 제5권1호
• /
• pp.67-85
• /
• 1993

The Purpose of this study was to evaluate the reliability and the validation of four scales of Questionnaire for Sasang Constitution Classification (QSCC), newly constructed through statistical item analysis and to examine their diagnostic discrimination power. QSCC was administered to 105 inpatient at Kyung-Hee Oriental Medicine Hospital and local oriental clinics and 136 undergraduated students. 2 weeks later, QSCC was readministered to 220 same subjects. Data were collected during about 2 months from february to Apr. 20, 1992. For the purposes of this study, the collected data were analyzed by internal consistancy, test-retest reliability, ANOVA, Pearson correlation and discrimination analysis of spss pc+ v3.0 program. The results were as follows: 1. The reliability of four scales of QSCC was relatively favorable. The internal consistancy and test-retest reliability of Tae-Yaung-In(太陽人) scale were respectively Cronbach's ${\alpha}=0.9$ and r=0.89. Those of So-Yaung-In(少陽人) scale were respectively ${\alpha}=0.81$ and r=0.93. Those of Tae-Em-In(太陰人) scale were respectively ${\alpha}=0.72$ and r=0.74. Those of So-Em-In(少陰人) scale were respectively ${\alpha}=0.81$ and r=0.93. 2. The diagnostic discrimination abilities(Hit-ratio=56%)of QSCC were found to have more about 20% improvement than propotional chance criteria(37%). Especially, Hit-ratios for So-Yaung-In(63%) and Tae-Em-In(60%) were more high than that for So-Em-In(48%) 3. For male subjects, the construct validity of QSCC was founded to be relatively favorable. But that of QSCC for females was poor.

• International Journal of Automotive Technology
• /
• 제7권1호
• /
• pp.1-7
• /
• 2006

The ignition delay of a dual fuel system has been numerically investigated by adopting a constant volume chamber as a model problem simulating diesel engine relevant conditions. A detailed chemical kinetic mechanism, consisting of 28 species and 135 elementary reactions, of dimethyl ether (DME) with methane ($CH_{4}$) sub-mechanism has been used in conjunction with the multi-dimensional reactive flow KIVA-3V code to simulate the autoignition process. The start of ignition was defined as the moment when the maximum temperature in the combustion vessel reached to 1900 K with which a best agreement with existing experiment was achieved. Ignition delays of liquid DME injected into air at various high pressures and temperatures compared well with the existing experimental results in a combustion bomb. When a small quantity of liquid DME was injected into premixtures of $CH_{4}$/air, the ignition delay times of the dual fuel system are longer than that observed with DME only, especially at higher initial temperatures. The variation in the ignition delay between DME only and dual fuel case tend to be constant for lower initial temperatures. It was also found that the predicted values of the ignition delay in dual fuel operation are dependent on the concentration of the gaseous $CH_{4}$ in the chamber charge and less dependent on the injected mass of DME. Temperature and equivalence ratio contours of the combustion process showed that the ignition commonly starts in the boundary at which near stoichiometric mixtures could exists. Parametric studies are also conducted to show the effect of additive such as hydrogen peroxide in the ignition delay. Apart from accurate predictions of ignition delay, the coupling between multi-dimensional flow and multi-step chemistry is essential to reveal detailed features of the ignition process.

• 한국세라믹학회지
• /
• 제51권6호
• /
• pp.527-532
• /
• 2014

$0.97Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3-0.03LaFeO_3$ lead-free piezoelectric ceramics were fabricated by a solid state reaction method. $LaFeO_3$ additives were added to $Bi_{0.5}(Na_{0.78}K_{0.22})_{0.5}TiO_3$ for volatile compensation of bismuth and sodium ions in the sintering process. To create A-site vacancies, the mole ratio and charge valence of A-site ions ($Bi^{3+}$, $Na^+$ and $K^+$) were controlled. The improved piezoelectric properties were observed by addition of $LaFeO_3$ and control of A-site vacancies. In particular, a $d_{33}^*(S_{max}/E_{max})$ value of 614pm/V and an electric field induced strain of 0.33% was observed in $0.97Bi_{0.505}(Na_{0.78}K_{0.22})_{0.485}TiO_3-0.03LaFeO_3$ ceramic.

• 대한환경공학회지
• /
• 제32권8호
• /
• pp.795-801
• /
• 2010

본 연구에서는 4종류의 상이한 생물 검정법(유전자 재조합 균주 RB1436 발광 활성, 4종 씨앗 발아, Bacillus lichemiformis의 ${\alpha}$-glucosidase 효소 활성, Salmonella typhimurium이용한 Ames test)을 이용하여 비소 화합물의 독성을 평가하였다. 검정법에 따라 상이한 민감도를 보였지만, 전체적으로 As(III)가 As(V)보다 높은 독성을 나타내었다. 씨앗 4종의 발아에 대한 민감도는 씨앗에 따라 상이하게 조사되었다. 상추(Lactucus)와 알타리무(Raphanus) 씨앗종이 대체적으로 높은 민감도를 보였으며 검정법에 적절한 씨앗종으로 조사되었다. 유전자 변이 검정법에서는 As(III)에 대해서는 1 mg/L 농도에서 TA 98 균주는 높은 복귀돌연변이 현상(MR = 5.1)이 조사되어, 높은 발암 가능성을 나타내었다. 비소화합물에 대해서 방법별 민감도는 일반적으로 효소 이외에는 높은 민감도를 나타내었다. 다양한 급성 독성 생물 검정법에 대한 통합 자료는 향후 오염원에 대한 독성 생물 평가에 유용하게 사용할 수 있을 것이다.

• Journal of Industrial and Engineering Chemistry
• /
• 제68권
• /
• pp.117-123
• /
• 2018

Recently, aqueous method has attracted lots of attention because it enables the solution-processed metal oxide thin film with high electrical properties in low temperature fabrication condition to various flexible devices. Focusing the development of aqueous route, many researchers are only focused on metal oxide materials. However, for expansive application of the aqueous-based metal oxide films, the systematic study of performance change with process variables for the development of aqueous-based metal oxide insulator film is urgently required. Here, we propose importance of process variables to achieve high electrical-performance metal oxide insulator based on the aqueous method. We found that the significant process variables including precursor solution temperature and humidity during the spincoating process strongly affect chemical, physical, and electrical properties of $AlO_x$ insulators. Through the optimization of significant variables in process, an $AlO_x$ insulator with a leakage current value approximately $10^5$ times smaller and a breakdown voltage value approximately 2-3 times greater than un-optimized $AlO_x$ was realized. Finally, by introducing the optimized $AlO_x$ insulators to solutionprocessed $InO_x$ TFTs, we successfully achieved $InO_x/AlO_x$ TFTs with remarkably high average field-effect mobility of ${\sim}52cm^2V^{-1}\;s^{-1}$ and on/off current ratio of 106 at fabrication temperature of $250^{\circ}C$.

• Journal of Veterinary Science
• /
• 제22권6호
• /
• pp.76.1-76.15
• /
• 2021

Background: The development of a vaccine for Jembrana disease is needed to prevent losses in Indonesia's Bali cattle industry. A DNA vaccine model (pEGFP-C1-tat) that requires a functional delivery system will be developed. Polylactic-co-glycolic acid (PLGA) may have potential as a delivery system for the vaccine model. Objectives: This study aims to evaluate the in vitro potential of PLGA as a delivery system for pEGFP-C1-tat. Methods: Consensus and codon optimization for the tat gene was completed using a bioinformatic method, and the product was inserted into a pEGFP-C1 vector. Cloning of the pEGFP-C1-tat was successfully performed, and polymerase chain reaction (PCR) and restriction analysis confirmed DNA isolation. PLGA-pEGFP-C1-tat solutions were prepared for encapsulated formulation testing, physicochemical characterization, stability testing with DNase I, and cytotoxicity testing. The PLGA-pEGFP-C1-tat solutions were transfected in HeLa cells, and gene expression was observed by fluorescent microscopy and real-time PCR. Results: The successful acquisition of transformant bacteria was confirmed by PCR. The PLGA:DNA:polyvinyl alcohol ratio formulation with optimal encapsulation was 4%:0.5%:2%, physicochemical characterization of PLGA revealed a polydispersity index value of 0.246, a particle size of 925 nm, and a zeta potential value of -2.31 mV. PLGA succeeded in protecting pEGFP-C1-tat from enzymatic degradation, and the percentage viability from the cytotoxicity test of PLGA-pEGFP-C1-tat was 98.03%. The PLGA-pEGFP-C1-tat demonstrated luminescence of the EGFP-tat fusion protein and mRNA transcription was detected. Conclusions: PLGA has good potential as a delivery system for pEGFP-C1-tat.

• Earthquakes and Structures
• /
• 제16권3호
• /
• pp.295-310
• /
• 2019

This study attempts to develop new simplified approximate formulas to predict the fundamental natural periods of vibration (T) for bearing wall systems engaged with special reinforced concrete shear walls (RCSW) under seismic loads. Commonly, seismic codes suggested empirical formulas established by regression analysis of measured T for buildings during earthquake motions. These formulas depend on structure type, building height, number, height and length of SW, and ratio of SW area to base area of structure. In this study, a parametric investigation is performed for T of 110 selected models of bearing RCSW systems with varying structural height, configuration of horizontal plans including building width, number and width of bays, presence of middle corridors and core SWs. For this purpose, a 3D non-linear response time history (TH) analysis is implemented using ETABS v16.2.1. New formulas to estimate T are anticipated and compared with those obtained from formulas of IBC 2012 and ASCE/SEI 7-10. Moreover, the study examines responses of an arbitrarily two selected test model of 60 m and 80 m in height with presence of SWs having middle corridors. It is observed that the performance of the tested buildings is different through arising of considerable errors when using codes' formulas for estimating T. Accordingly, using the present proposed formulas exhibits more reasonable and safer design compared to codes' formulas. The results showed that equitable enhancement is promising to improve T formulas approaching enhanced and accurate estimation of T with reliable analysis, design, and evaluation of bearing RCSW systems.