• Title/Summary/Keyword: differential coefficient

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Factors Affecting the Social Distance toward Older Adults of Nursing Students (간호대학생의 노인에 대한 사회적 거리감 영향요인)

  • Ha, Jiyeon;Park, Ju Young
    • Research in Community and Public Health Nursing
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    • v.30 no.4
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    • pp.539-549
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    • 2019
  • Purpose: The aim of this study was to identify the factors related to the social distance toward older adults in nursing college students. Methods: The participants comprised 137 students in a nursing college. Data were collected using self-report questionnaires in March 2019. The measurement instruments included social distance scales, the Fact on Aging Quiz (FAQ I), a 20-item semantic differential scale (to assess attitudes), and the perceived elderly stigma scale. The data were analyzed using descriptive statistics, independent t-tests, one-way analysis of variance (ANOVA), Pearson's correlation coefficient, and a multiple regression analysis. Results: The total score for social distance toward older adults was 3.98±0.54 out of a maximum of 5. Social distance had a statistically significant relationship with knowledge (r=.20, p=.022), attitudes toward older adults (r=-.31, p<.001), and elderly stigma (r=-.27 p=.008). The factors affecting social distance were education in geriatrics (β=.33, p=.004), grade (β=-.29, p=.014), attitudes (β=-.21, p=.018), academic major satisfaction (β=.19, p=.028), and knowledge (β=.15, p=.048); the explanatory power of the model was 34%. Conclusion: There is a need for departmental efforts that nursing students acquire correct knowledge about the life and health of the elderly with the aging process and develop positive attitudes toward older adults through various experiences in gerontological nursing practicum and community senior-college student link programs.

Empirical Determination of a CT X-ray Spectra by Numerical Analysis using Transmission Data (투과선량의 수치해석에 의한 전산화단층영상장치 X선의 에너지 분포결정)

  • 최태진;김옥배;서수지
    • Progress in Medical Physics
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    • v.8 no.2
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    • pp.35-43
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    • 1997
  • The knowledge of x-ray spectra is highly desirable in some investigation involves the differential penetrating power and absorption coefficient correction of various photon beam. The transmission data were obtained from the 80 kVp and 120 kVp of CT x-ray beam with the aluminium filter which is designed in a 30 cm of diameter and pipe-typed filter was prepared from 5.0 mm upto 92.3 mm of thickness. To obtain the reconstructed spectra of CT x-ray, the investigator used the iterative numerical analysis which has been extended to include the tungsten characteristics from experimental transmission data with energy interval of 2 keV. Comparison of the calculated transmission data from the reconstructed spectra with that of measurement shows good agreement in both 80 kVp and 120 kVp x-ray beams. This numerical analysis based on iteratively calculation of fractional exposure per energy interval shows the high potential of usefulness of determination the x-ray spectra from the attenuated beam in diagnostic energy range.

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Characteristic equation solution of nonuniform soil deposit: An energy-based mode perturbation method

  • Pan, Danguang;Lu, Wenyan;Chen, Qingjun;Lu, Pan
    • Geomechanics and Engineering
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    • v.19 no.5
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    • pp.463-472
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    • 2019
  • The mode perturbation method (MPM) is suitable and efficient for solving the eigenvalue problem of a nonuniform soil deposit whose property varies with depth. However, results of the MPM do not always converge to the exact solution, when the variation of soil deposit property is discontinuous. This discontinuity is typical because soil is usually made up of sedimentary layers of different geologic materials. Based on the energy integral of the variational principle, a new mode perturbation method, the energy-based mode perturbation method (EMPM), is proposed to address the convergence of the perturbation solution on the natural frequencies and the corresponding mode shapes and is able to find solution whether the soil properties are continuous or not. First, the variational principle is used to transform the variable coefficient differential equation into an equivalent energy integral equation. Then, the natural mode shapes of the uniform shear beam with same height and boundary conditions are used as Ritz function. The EMPM transforms the energy integral equation into a set of nonlinear algebraic equations which significantly simplifies the eigenvalue solution of the soil layer with variable properties. Finally, the accuracy and convergence of this new method are illustrated with two case study examples. Numerical results show that the EMPM is more accurate and convergent than the MPM. As for the mode shapes of the uniform shear beam included in the EMPM, the additional 8 modes of vibration are sufficient in engineering applications.

The Prediction of Temperature in Composite Box Girder Bridges (합성 박스형 교량의 온도 예측)

  • Chang, Sung Pil;Im, Chang Kyun
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.431-440
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    • 1997
  • The paper describes a theoretical model for the prediction of bridge temperatures from meteorological data measured at bridge site and local meteorological center together with existing finite element heat transfer theory and solar radiation transfer theory to determine the time dependent temperature distribution of bridge. In this analytical model, the most adequate equation for the calculation of solar radiation on the bridge surface, which is dominant in day time is described based on the results of several experimental studies for the solar energy. The validity of this model is tested against field data obtained from long term experimental program on Sadang Viaduct in Seoul. Also, this paper describes the linear correlation between design variables and meteorological data to establish analytical criteria for the prediction of the average temperature, which are responsible for the longitudinal deformation of the bridges and of the vertical differential temperature profiles. which are responsible for the bending deformations from the long term experimental results.

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Characteristic of Underfill with Various Epoxy Resin (에폭시 수지에 따른 언더필의 특성에 관한 연구)

  • Noh, Bo-In;Lee, Jong-Bum;Jung, Seung-Boo
    • Journal of the Microelectronics and Packaging Society
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    • v.13 no.3 s.40
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    • pp.39-45
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    • 2006
  • This study was investigated the thermal properties of underfill with various epoxy resins using thermal analysis methods such as differential scanning calorimetry (DSC), thermo gravimetry analysis (TGA), dynamic mechanical analysis (DMA) and thermo-mechanical analysis (TMA). And, the adhesion strength of the underfills/FR-4 substrate was evaluated. The glass transition temperature (Tg) of underfill which was composed the cycolaliphatic epoxy resin was lower than that of underfill which was not composed the cycolaliphatic epoxy resin. The thermal degradation of underfill was composed of two processes, which involved chemical reactions between the degrading polymer and oxygen from the air atmosphere. The coefficient of thermal expansion (CTE) of underfill which was composed the cycolaliphatic epoxy resin was higher than that of underfill which was not composed the cycolaliphatic epoxy resin. The excessive curing temperatures caused a weak boundary layer of epoxy resin, which resulted in a deterioration of mechanical properties in the epoxy resin and thus led to poor adhesion property between the underfill/FR-4 substrate.

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A Study on the Protecting Wall for Transferring Pipe of Waste Using Cast Basalt Tube (용융주조 현무암 튜브를 이용한 생활폐기물 이송관로의 보호벽에 관한 연구)

  • Wang, Jee-Seok;Kim, Jong-Do;Yoon, Hee-Jong
    • Journal of Advanced Marine Engineering and Technology
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    • v.34 no.6
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    • pp.816-824
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    • 2010
  • The forces applying to an object in the transferring pipe of waste are analyzed and the equation of motion is established in this paper. It is shown that the equation of motion becomes the 1st order non-linear differential equation. Using its general solution, the velocity of the object in the transferring pipe of waste can be expressed in the explicit form. Noting that the velocity of object is impact velocity to the elbow or curved part of the transferring pipe of waste, the kinetic energy of the object can be calculated and the necessary impact strength of inner wall is obtained. The velocity of object is also calculated and presented in the graphic forms with the condition of air velocity 30m/sec. The impact test of cast basalt tube is carried out by the free fall of a weight and the test results show that the impact strength of the cast basalt tube is sufficient to apply to protecting inner wall of the transferring pipe of waste.

Pharmaceutical Study on Pranoprofen Argininate and Pranoprofen Lysinate (Pranoprofen Argininate 및 Pranoprofen Lysinate의 약제학적 연구)

  • Jee, Ung-Kil
    • Journal of Pharmaceutical Investigation
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    • v.17 no.4
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    • pp.197-204
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    • 1987
  • Novel pranoprofen algininate and lysinate salts were manufactured and their salt formation was confirmed by melting point, infrared spectroscopy, nuclear magnetic resornance spectroscopy, differential scanning calorimetry and powder X-ray diffractometry. The physical properties of pranoprofen lysinate and argininate salts were compared with those of pranoprofen through in vitro and in vivo tests. Solubility, $pK_a$ and lipid-water partition coefficient were measured through in vitro experiments, while antiinflammatory efficacy, analgesic effect, acute toxicity and in situ absorption were tested through in vivo experiments. The results obtained were as follows: 1) The solubilities of pranoprofen argininate and lysinate salts were increased markedly in pH 6.8 and pH 7.5 phosphate buffer solutions, comparing with that of pranoprofen itself. 2) $pK_a$ values of pranoprofen, pranoprofen argininate and lysinate salts were 6.34, 7.99 and 7.56 in carbon tetrachloride, and 5.86, 6.69 and 7.92 in chloroform, respectively by liquid-liquid partition method. 3) The lipid-water partition coefficients of pranoprofen argininate and lysinate salts were increased more than that of pranoprofen in carbon tetrachloride, chloroform, or benzene-pH 6.8 buffer system, but were nearly identical using pH 1.2 buffer as water phase. 4) Antiinflammatory effects of pranoprofen argininate and lysinate salts were remarkably increased and analgesic effects of the salts were as same as that of pranoprofen. 5) Pranoprofen argininate and lysinate salts were safer than pranoprofen itself in acute toxicity, and the in situ absorption rates of pranoprofen, pranoprofen argininate and lysinate salts were 0.392, 0.960 and $0.762\;hr^{-1}$, respectively according to the rat intestine recirculation experiment.

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Kinetic Analysis of Oxidative Coupling of Methane over Na+/MgO Catalyst (Na+/MgO 촉매상에서 메탄의 Oxidative Coupling 반응의 속도론적 해석)

  • Seo, Ho-Joon;Sunwoo, Chang-Shin;Yu, Eui-Yeon
    • Applied Chemistry for Engineering
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    • v.5 no.4
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    • pp.580-587
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    • 1994
  • The oxidative coupling of methane was studied kinetically using $Na^+(50wt%)/MgO$ catalyst at 710, 730, 750, 770 and $790^{\circ}C$ in a fixed bed flow reactor at the atmospheric pressure under differential conversion conditions. Through curve fitting, it was found that the Langmuir-Hinshelwood type mechanism was fitted to this reaction rather than Rideal-Redox type or Eley-Rideal type mechanism. Therefore, it was proposed that the $O_2{^-}$ or $O_2{^{2-}}$ species on the surface was related to the production of $CH_3{\cdot}$. The estimated activation energy of $CH_3{\cdot}$ production was about 39.3kcal/mol. Moreover, as the result of curve fitting, the stoichiometric coefficient of $O_2$ for the production of $CH_3{\cdot}$ to produce $CO_x$was approximately 1.5. Accordingly, it could be concluded that the $CH_3O_2{\cdot}*$ was prouduced through the partial oxidation of $CH_3{\cdot}$ with the surface oxygen.

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Effect of Calcination Temperature of Size Controlled Microstructure of LiNi0.8Co0.15Al0.05O2 Cathode for Rechargeable Lithium Battery

  • Park, Tae-Jun;Lim, Jung-Bin;Son, Jong-Tae
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.357-364
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    • 2014
  • Size controlled, $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$ cathode powders were prepared by co-precipitation method followed by heat treatment at temperatures between 750 and $850^{\circ}C$. The synthesized samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance. The synthesized $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$ after calcined at $750^{\circ}C$ has a good electrochemical performance with an initial discharge capacity of $190mAhg^{-1}$ and good capacity retention of 100% after 30 cycles at 0.1C ($17mAg^{-1}$). The capacity retention of $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$ after calcined at $750^{\circ}C$ is better than that at 800 and $850^{\circ}C$ without capacity loss at various high C rates. This is ascribed to the minimized cation disorder, a higher conductivity, and higher lithium ion diffusion coefficient ($D_{Li}$) observed in this material. In the differential scanning calorimetry DSC profile of the charged sample, the generation of heat by exothermic reaction was decreased by calcined at high temperature, and this decrease is especially at $850^{\circ}C$. This behavior implies that the high temperature calcinations of $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$ prevent phase transitions with the release of oxygen.

Structural Modification of Alkali Tellurite Binary Glass System and Its Characterization

  • Lee, Kyu-Ho;Kim, Tae-Ho;Kim, Young-Seok;Jung, Young-Joon;Na, Young-Hoon;Ryu, Bong-Ki
    • Korean Journal of Materials Research
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    • v.18 no.5
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    • pp.235-240
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    • 2008
  • This paper presents results and observations obtained from a study of the optical and thermal properties of alkali tellurite depending on the composition. Fourier transform infrared (FT-IR) spectra showed evidence of chemical modification from $TeO_4$ trigonal bipyramids (tbp) to $TeO_3$ trigonal pyramids (tp) in tellurite glasses. The optical band gaps of the different glass samples calculated using Tauc's method were found to range from 3.5-3.8 eV. The glass transition temperature (Tg) and glass stability (${\Delta}T$) of alkali tellurite glasses were investigated, as $M_2O$ [M: Li, Na, K] amounted to 25 mol%, through the use of differential thermal analysis (DTA). The coefficient of thermal expansion (CTE) was measured in a thermo mechanical analysis (TMA) with a slow heating rate after the glass samples were annealed. The results confirm that the optical band gap of alkali tellurite glasses depends on the Te-O-Te structural relaxation related to the ratio of bridging/non bridging oxygen (BO/NBO). In contrast, the thermal properties are related to the ionic field strength of the Te-O-M and M-O-M bonds, and the Te-O-Te breakage depends on the ratio of BO/NBO.