• Title/Summary/Keyword: $C^*$-매개변수

Search Result 323, Processing Time 0.03 seconds

Study about The Effect Alcohol and The Temperature Exert on $TiO_2$ Particle Production by Sedimentation Method (침전법을 이용한 이산화티탄 입자 제조에 알콜과 온도가 미치는 영향에 관한 연구)

  • Kim, Duck-Sool
    • Journal of the Korean Applied Science and Technology
    • /
    • v.29 no.3
    • /
    • pp.495-502
    • /
    • 2012
  • Using the Sedimentation method it's possible to get $TiO_2$ particle from which by this research, $TiO_2$ particle was produced. The parameter in the kind of the temperature and the alcohol solvent used $TiO_2$ particle production investigated crystal structure of $TiO_2$ particle and the influence exerted on the size of the particle and the form. After scanning electron microscope (SEM) analyzed methyl alcohol, iso-propylalcohol and tert-butylalcohol used by a solvent at the $TiO_2$ particle production, iso-propylalcohol was most effective. And after an thermogravimetric analyzer method was used, the anatase structure was maintained $500^{\circ}C$ by $200^{\circ}C$, but it was converted by the rutile structure by $800^{\circ}C$.

Structural Optimal Design of the Frame of a Desktop Servo Pressing Machine (탁상용 압입기 프레임의 구조최적설계)

  • Lee, Boo-Youn;Jung, Jin-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.14 no.7
    • /
    • pp.3142-3150
    • /
    • 2013
  • Present research deals with an optimal design of the C-type frame of a desktop pressing machine to minimize its deformation which plays an important role in accuracy of the machine. Deformation pattern of the frame is analyzed by the finite element method. Design parameters are defined for the frame to derive an optimal design. Displacement and weight sensitivities of the parameters are analyzed using the method of the parametric study. On the basis of the response curves for the parameters, optimal designs of the frame are proposed. Effectiveness of the optimal design is verified by analyses in the viewpoint of the deformation and weight of the frame. Deformation of the optimized frame without increase of the weight is 87.5 % of the original frame.

Fire Resistance of Circular Internally Confined Hollow Reinforced Concrete Column (원형 내부 구속 중공 철근콘크리트 기둥의 내화 성능)

  • Won, Deok-Hee;Han, Taek-Hee;Lee, Gyu-Sei;Kang, Young-Jong
    • Journal of Korean Society of Steel Construction
    • /
    • v.22 no.2
    • /
    • pp.139-150
    • /
    • 2010
  • Reinforced-concrete (RC) columns are frequently designed and constructed. other types of columns includes composite types such as concrete-filled tube columns (CFT). Hollow RC columns may be effective in reducing both the self weight of columns and total amount of materials used. This is due to the fact that a hollow RC column possesses larger moment of inertia than that of solid RC columns of same cross sectional area. Despite the effectiveness the hollow RC column has not been popular because of its poor ductility performance. While the transverse reinforcements are effective in controlling the brittle failure of the outside concrete, they are not capable of resisting the failure of concrete of inner face which is in unconfined state of stress. To overcome these drawbacks, the internally confined hollow reinforced concrete (ICH RC), a new column type, was proposed in the previous researches. In this study, the fire resistance performance of the ICH RC columns was analyzed through a series of extensive heat transfer analyses using the nonlinear-material model program. Also, effect of factors such as the hollowness ratio, thickness of the concrete, and thickness of the internal tube on the fire resistance performance were extensively studied. Then the factors that enhance the fire-resistant performance of ICH RC were presented and analyzed.

The Mediating Effect of the Turnover Intention between the Empowerment and the Burnout of Professionals in Rehabilitation Centers for the Handicapped (장애인복지관 전문인력의 임파워먼트와 소진의 관계에서 이직의도의 매개효과)

  • Lee, Byoung-Rock
    • Journal of Digital Convergence
    • /
    • v.19 no.11
    • /
    • pp.511-516
    • /
    • 2021
  • This research verified the influence of the empowerment on the burnout and the mediating effect of the turnover intention of professionals in the rehabilitation centers. A survey of 363 professionals working in the facilities of D Metropolitan City and C Province was conducted. The important analysis methods are correlation, confirmatory factor analysis, and bootstrap test. The research results are as follows : the professionals' empowerment influenced burnout negatively and the turnover intention mediated between the empowerment and the burnout. According to this analysis results, it is important to improve the empowerment and to lower the turnover intention for reducing the burnout. And some measures were suggested to improve the empowerment and to lower the turnover intention.

The Effect of Smart Safety and Health Activities on Workers' Intended Behavior (스마트 안전보건활동이 근로자의 의도된 행동에 미치는 영향)

  • Choonhwan Cho
    • Journal of the Society of Disaster Information
    • /
    • v.19 no.3
    • /
    • pp.519-531
    • /
    • 2023
  • With the aim of preventing safety accidents at construction sites, the company aims to create safe behaviors intended through variables called smart safety and health activities to help reduce industrial accidents. Purpose: It analyzes how smart safety and health activities affect accidents caused by unsafe behavior and changes in worker behavior, which is the root cause, and verifies the hypothesis that it helps prevent safety accidents and protect workers' lives. Method: Smart safety and health activities were selected as independent variables (X), and intended safety and anxiety, which are workers' behavioral intentions, were set as dependent variables (Y), attitude and subjective norms, and planned behavioral control as parameters (M). Exploratory factor analysis, discriminant validity analysis, and intensive validity analysis of safety and health activities were used to analyze the scale's reliability and validity. To verify the hypothesis of behavior change, the study was verified through Bayesian model analysis and MC simulation's probability density distribution. Result: It was found that workers who experienced smart safety and health activities at construction sites had the highest analysis of reducing unstable behavior and performing intended safety behavior. The research hypothesis that this will affect changes in worker behavior has been proven, the correlation between variables has been verified in the structural equation and path analysis of the research analysis, and it has been confirmed that smart safety and health activities can control and reduce worker instability. Conclusion: Smart safety and health activities are a very important item to prevent accidents and change workers' behavior at construction sites.

A New and Efficient C0 Laminated Curved Beam Element (효율적인 C0 적층 곡선보 요소의 개발)

  • Kim, Jin-Gon;Kang, Sang-Wook
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.27 no.4
    • /
    • pp.559-566
    • /
    • 2003
  • In this study, we present a new highly accurate two-dimensional curved composite beam element. The present element, which is based on the Hellinger-Reissner variational principle and classical lamination theory, employs consistent stress parameters corresponding to cubic displacement polynomials with additional nodeless degrees to resolve the numerical difficulties due to the spurious constraints. The stress parameters are eliminated and the nodeless degrees are condensed out to obtain the (9x9) element stiffness matrix. It should be noted that the stacking sequences without transverse deformation to the load plane makes a two dimensional analysis of curved composite beams practically useful . Several numerical examples confirm the superior locking-free behavior of the present higher-order laminated curved beam element.

The effects of Live Commerce Characteristic on Brand image, Trust and Repurchase Intention (라이브 커머스의 특성이 브랜드 이미지, 신뢰 및 재구매의도에 미치는 영향)

  • Jae-Man, Yoon;Hyung-Seog, Lee;Da-Yeon, Choi;In-suk Lee
    • Journal of Industrial Convergence
    • /
    • v.22 no.9
    • /
    • pp.1-15
    • /
    • 2024
  • We examine the studies on the effect of four live commerce characteristics on repurchase intention through brand image and trust. We conducted a path analysis of 215 people who have used live commerce. As the results, first, live commerce's entertainment and interactivity had a positive effect on the brand image. Second, economics and entertainment, brand image had a positive effect on trust. Third, trust had a positive effect on repurchase intention. Fourth, trust and brand image mediate the relationship between entertainment, functionality and repurchase. We explains which live commerce characteristics that companies and local governments that provide live commerce services should strive to enhance in their strategies and service offerings, and how they should enhance their brand image and trust to elicit consumers' repurchase intentions. Also, this study is significant in that it provides a theoretical foundation for future research.

Antimicrobial Activity of Florfenicol Against Fish Pathogenic Bacteria and Pharmacokinetics in Blood of Cultured Olive Flounder by Oral Administration (Florfenicol의 어류 병원성 세균에 대한 항균 효과와 경구 투여후 넙치 혈액에서의 약물동태학적 특성)

  • Jung, Sung-Hee;Seo, Jung-Soo
    • Journal of Fisheries and Marine Sciences Education
    • /
    • v.25 no.5
    • /
    • pp.1079-1087
    • /
    • 2013
  • The pharmacokinetics of florfenicol (FF) after oral administration was studied in the cultured olive flounder, Paralichthys olivaceus, using high performance liquid chromatography (HPLC). After single administration of FF (20 mg/kg body weight) by oral route in olive flounder ($700{\pm}50$ g, $23{\pm}1.5^{\circ}C$), the concentration in the serum was determined at 1, 5, 10, 15, 24, 30, 50 and 168 h post-dose. The kinetic profile of absorption, distribution and elimination of FF in serum were analyzed fitting to a two-compartment model by WinNonlin program. The area under the concentration-time curve (AUC), maximum concentration ($C_{max}$), time for maximum concentration ($T_{max}$) and elimination time were 22.51 ${\mu}g{\cdot}h/mL$, 0.84 ${\mu}g/mL$, 8.62 h and 447 h, respectively. The results of this study related to dosage and withdrawal times could be used for prescription of FF in field for the treatment of bacterial diseases in olive flounder.

Experimental and Numerical Study of the Thermal Decomposition of an Epoxy-based Intumescent Coating (실험과 계산을 통한 에폭시 계열 내화도료의 열분해에 관한 연구)

  • Kim, Yangkyun
    • Fire Science and Engineering
    • /
    • v.30 no.1
    • /
    • pp.31-36
    • /
    • 2016
  • This study investigates the characteristics of thermal decomposition of an epoxy-based intumescent paint using thermogravimetric analysis (TGA) and numerical simulation. A mathematical and numerical model is introduced to describe mass loss profiles of the epoxy-based intumescent coating induced by the thermal decomposition process. The decomposition scheme covers a range of complexity by employing simplified 4-step sequential reactions to describe the simultaneous thermal decomposition processes. The reaction rates are expressed by the Arrhenius law, and reaction parameters are optimized to fit the degradation behavior seen during thermogravimetric (TG) experiments. The experimental results show a major 2-step degradation under nitrogen and a 3-step degradation in an air environment. The experiment also shows that oxygen takes part in the stabilization of the intumescent coating between 200 and $500^{\circ}C$. The simulation results show that the proposed model effectively predicts the experimental mass loss as a function of time except for temperatures above $800^{\circ}C$, which were intentionally not included in the model. The maximum error in the simulation was less than 3%.

A Study on the Estimation of Sediment Yield Based on a Distributed System Concept (분포형 개념을 이용한 토사유출량 산정에 관한 연구)

  • Kim, Ung-Tae;Yun, Yong-Nam;Park, Mu-Jong;Yu, Cheol-Sang
    • Journal of Korea Water Resources Association
    • /
    • v.34 no.2
    • /
    • pp.131-140
    • /
    • 2001
  • The present study is focused on improving the methodology for the determination of parameters involved in USLE(Universal Soil Loss Equation) based on distributed system concept and investigation of sediment delivery ratio. Generally the distributed system concept consists of grid networks throughout the watershed and sediment can be traced from grid to rid in the direction of the steepest descent. The sediment yield data together with physical data of 10 small irrigation reservoirs in Kyounggi-Do are collected. After the sediment delivery ratio of a grid is defined to be related tothe fraction of forested or covered with delivery proofing area of the grid, the preportionality coefficient(C$_1$) is introduced. The distributed system model is calibrated using the available data for 8 reservoirs and is verified with the data for the ramaining 2 reservoirs, and regression analysis is made to express the proportionality coefficient $C_1$ in terms of watershed physical characteristics. By applying this results the verification of the distributed system model for 2 reservoirs showed a fair result, which justifies the applicability of the proposed method in the present study.

  • PDF