• 제목/요약/키워드: Cross-relaxation

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A Study on Preference and Behavior of Forest Path Users

  • Seo, Yeongwan;Jung, Sanghyun;Jeong, Sooncheol;Kim, Soyeon;Choi, Jungkee
    • Journal of Forest and Environmental Science
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    • v.37 no.3
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    • pp.260-268
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    • 2021
  • This study was conducted to grasp users' preferences and behavior of forest paths and to provide basic data for forest path construction in the future. Among forest path users, males and females over 20 years old were surveyed on forest path preferences, motives for visiting, using time and distance, companions, and sources for obtaining information on forest paths. A total of 587 people participated in the questionnaire, and cross-analysis was conducted simultaneously using the SPSS statistical program. In analyzing the preference of forest paths, it was found that male and the general public preferred trekking path for activities while female and foresters preferred forest path for relaxation and healing (p<0.05). As for the motives for visiting forest paths, the response that they visited for a walk/rest was the highest in gender, occupation, and age group. As for the number of annual visits, less than 5 was the highest in overall, and foresters tended to visit forest path more often than the general public, and the number of visits to the forest paths increased with age (p<0.01). The most common route to acquire information about forest paths is the Internet, while the Internet use is relatively low in those over 60s (p<0.05). The response ratio of accompanying their family in visiting forest paths were the highest, while the response in their 20s and 60s was the most in accompanying their friends (p<0.05).

A Study on the Typological Alteration of the Courtyard in Modern Architecture (현대건축에서 나타나는 중정의 유형 변화에 관한 연구)

  • Lee, Jung-Min;Kim, Kook-Sun;Woo, HyunYong
    • Korean Institute of Interior Design Journal
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    • v.21 no.4
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    • pp.40-47
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    • 2012
  • Courtyard is evolving from the conventional one element of a building far beyond into independent peremeter of urban architecture, of which function has been darmatically upgraded from embedded traditional air fluiding, nutural lighting system into where full fledged function can be experienced so much as your imagimation reaches taking major social responsibility such as intact offline social networking which links people from neighbors, inter / extra buiding openness which allow people can communicate among othewise between themselves and artificial natural environmental emelents supplier where people resort to relaxation and natural healing. Roles of courtyard has been by far streatched out into nearby natural healing space where people can shake off their unavoidable stresses from the modern life relaxing themselves looking at the sky otherwise observe natural surroundigns such as plants, flowers and waters. Thanks to hereonto mentioned its merits, Courtyard building is widely used and seen as a center of modern urban design in residence, public bilding and urban planned buildings. Courtyard biulding is nowadays boasting their morphological diversity brought out from lots of topological variation, type variants, cross section and inter relationship with the other neighboring spaces. Hence, hereby I have been studied how above mentioned three major peremeters of courtyard has been upgraded in modern architecture comparing the period from 1960 to 1990 and the period starting from 1991.

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Non-destructive assessment of the three-point-bending strength of mortar beams using radial basis function neural networks

  • Alexandridis, Alex;Stavrakas, Ilias;Stergiopoulos, Charalampos;Hloupis, George;Ninos, Konstantinos;Triantis, Dimos
    • Computers and Concrete
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    • v.16 no.6
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    • pp.919-932
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    • 2015
  • This paper presents a new method for assessing the three-point-bending (3PB) strength of mortar beams in a non-destructive manner, based on neural network (NN) models. The models are based on the radial basis function (RBF) architecture and the fuzzy means algorithm is employed for training, in order to boost the prediction accuracy. Data for training the models were collected based on a series of experiments, where the cement mortar beams were subjected to various bending mechanical loads and the resulting pressure stimulated currents (PSCs) were recorded. The input variables to the NN models were then calculated by describing the PSC relaxation process through a generalization of Boltzmannn-Gibbs statistical physics, known as non-extensive statistical physics (NESP). The NN predictions were evaluated using k-fold cross-validation and new data that were kept independent from training; it can be seen that the proposed method can successfully form the basis of a non-destructive tool for assessing the bending strength. A comparison with a different NN architecture confirms the superiority of the proposed approach.

Tb3+ and Ce3+ Intercalated Laponite Powder: The Influence of Ce3+ Ions on Thermal Stability and Optical Properties of Tb3+ Intercalated Laponite

  • Lee, Han-Na;Kim, You-Hyuk
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1273-1276
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    • 2011
  • Laponite samples intercalated with $Tb^{3+}$ or $Tb^{3+},Ce^{3+}$ ions were prepared by exchange of Na+ ions in interlayers with $Tb^{3+}$ or $Ce^{3+}$ ions. Strong green and weak blue emissions under vacuum ultraviolet (VUV) excitation (${\lambda}$ = 158 nm) were observed due to the $^5D_4{\rightarrow}^7F_J$ and $^5D_3{\rightarrow}^7F_J$ emission lines, respectively. $Tb^{3+}$ ions in an interlayer of laponite mainly existed in ion pairs or clusters, as evidenced by the concentration-dependent luminescence of the $Tb^{3+}$ ions on the relative intensities of the $^5D_3{\rightarrow}^7F_J$ and the $^5D_4{\rightarrow}^7F_J$ emission lines, due to the action of a cross-relaxation process. The addition of $Ce^{3+}$ ions increased the thermal stability of $Tb^{3+}$ intercalated laponite up to $650^{\circ}C$ and quenched the $^5D_3{\rightarrow}^7F_J$ emission lines, probably by promoting the formation of $Tb^{3+}$ ion pairs at relatively low $Tb^{3+}$ concentrations.

Oxidation and mechanical relaxation properties of chlorinated LDPE film (염소 처리된 저밀도 폴리에틸렌 필름의 산화 및 기계적 완화 특성)

  • 황명환;박동화;박구범
    • Journal of the Korean Society of Safety
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    • v.6 no.3
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    • pp.27-34
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    • 1991
  • This paper is for the properties of the oxidation-proof of the partially discharged and of the molecular motion on chlorinated PE Film. this paper also shows the properties of the molecular motion of the ${\gamma}$ ray irradiated PE Film. 1 In the surface of the PE Film enforce chlorination, C-Cl be distributed up to 10 $\mu$m deep. 2. In according to the development of the chlorination, the measure of crystalization decreased and cross link occured. 3. Chlorination PE Film control the oxidation on ozone to occuratlon by partial discharge and it lost bonding chlorine. 4. in according to chlorination, ${\gamma}$ absorption in motion of CH2 main chain of PE drcreased by chlorine stbstitution.

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Magnetic Resonance Imaging as a Biomarker for Duchenne Muscular Dystrophy

  • Lim, Woo-taek
    • Physical Therapy Korea
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    • v.22 no.3
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    • pp.98-105
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    • 2015
  • Muscular dystrophy is a hereditary musculoskeletal disorder caused by a mutation in the dystrophin gene. Duchenne muscular dystrophy (DMD) is one of the most common, and progresses relatively faster than other muscular dystrophies. It is characterized by progressive myofiber degeneration, muscle weakness and ultimately ambulatory loss. Since it is an X-linked recessive inheritance, DMD is mostly expressed in males and rarely expressed or less severe in females. The most effective measurement tool for DMD is magnetic resonance imaging (MRI), which allows non-invasive examination of longitudinal measurement. It can detect progressive decline of skeletal muscle size by measuring a maximal cross-sectional area of skeletal muscle. Additionally, other techniques in MRI, like $T_2$-weighted imaging, assess muscle damage, including inflammation, by detecting changes in $T_2$ relaxation time. Current MRI techniques even allow quantification of metabolic differences between affected and non-affected muscles in DMD. There is no current cure, but physical therapist can improve their quality of life by maintaining muscle strength and function, especially if treatment (and other forms of medical intervention) begins in the early stages of the disease.

MINLP optimization of a composite I beam floor system

  • Zula, Tomaz;Kravanja, Stojan;Klansek, Uros
    • Steel and Composite Structures
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    • v.22 no.5
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    • pp.1163-1192
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    • 2016
  • This paper presents the cost optimization of a composite I beam floor system, designed to be made from a reinforced concrete slab and steel I sections. The optimization was performed by the mixed-integer non-linear programming (MINLP) approach. For this purpose, a number of different optimization models were developed that enable different design possibilities such as welded or standard steel I sections, plastic or elastic cross-section resistances, and different positions of the neutral axes. An accurate economic objective function of the self-manufacturing costs was developed and subjected to design, resistance and deflection (in)equality constraints. Dimensioning constraints were defined in accordance with Eurocode 4. The Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm was applied together with a two-phase MINLP strategy. A numerical example of the optimization of a composite I beam floor system, as presented at the end of this paper, demonstrates the applicability of the proposed approach. The optimal result includes the minimal produced costs of the structure, the optimal concrete and steel strengths, and dimensions.

Changes in Physical Properties of Paper by Solvent-Bonding between Cellulose Fibers Using Aqueous Solution of N-Methylmorpholine N-Oxide (N-Methylmorpholine N-Oxide 수용액을 이용한 셀룰로오스 섬유들간의 용제접착에 의한 종이의 물성 변화)

  • 이양헌;박찬헌;이현진;이선희
    • Textile Coloration and Finishing
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    • v.11 no.1
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    • pp.34-41
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    • 1999
  • To examine the increase of paper strength by solvent-bonding using N-methylmorpholine N-oxide (NMMO), a paper was treated with aqueous solutions of NMMO, concentrated at $90^\circ{C}$ for selected periods of time, and pressed for 5 seconds followed by washing and drying. The effect of the increasing NMMO concentration on bonding state and some important properties of samples were mainly investigated. With increasing concentration of NMMO, the degree of bonding between fibers was increased, the fiber cross-sectional shape was changed from 'thin ribbonlike' to 'round rodlike' by swelling with solvent, and the longitudinal waves (crimp) were introduced to fibers, hence the shrinkage, weight per unit area, and thickness of paper were increased. Consequently, the tensile strength and elongation, under standard and wet conditions, and the stiffness were increased, and the water absorption was decreased generally with increasing concentration of NMMO. The moisture regain of treated samples was lower than that of the untreated sample, because of the reduction of space between fibers. But the moisture regain was increased a little with increasing concentration of NMMO due to the fiber swelling with NMMO followed by structural relaxation.

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A Study on Behavioral Characteristics of Track Roadbed according to Steel Pipe Press-in Excavation during Construction of Underground Railway Crossing

  • Kim, Young-Ha;Eum, Ki-Young;Kim, Jae-Wang
    • International Journal of Railway
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    • v.6 no.2
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    • pp.69-77
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    • 2013
  • In this study, numerical analysis and model experiments were conducted to analyze behavioral characteristics acting on the track roadbed with excavation through steel pipe injection, a non-exclusive method of crossing construction under railroad as primary target. In model experiments that simulate injection excavation behaviors with an increase in the depth of soil cover, the upper displacement was measured by construction of the first and the second pipes in order to predict actual behaviors, and the behavior characteristics were verified through numerical analysis. The investigation results showed that surface displacement was smaller under the condition of higher soil cover. In the case of injecting two pipes, when the first pipe was injected, deformation of the surface increased linearly in both settlement and uplift experiments. However, when the second pipe was injected, the amount of change was found to be very small due to the relaxation and plastic zones around the first pipe. In addition, the results of numerical analysis on the same cross section with the model experiment found that the results of investigation into settlement ratio and volume loss were in very good agreement with those obtained by the model experiment.

Sensitivity Analysis for Flexural Behaviors of PSC Members (프리스트레스트 콘크리트 휨 부재의 민감도 해석)

  • Lee, Jon-Ja;Lee, Bong-Goo;Kim, Min-Joo;Lee, Yong-Hak
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.2
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    • pp.183-194
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    • 2002
  • A general procedure to evaluate the sensitivity of design variables to stresses and strains in PSC flexural members is proposed. To accomplish the purpose of this study, long-term losses including creep, shrinkage, and PS steel relaxation are formulated based on the equilibrium states of the deformed sectional geometry. Thereby, the formulation follows the basic steps which consider the fundamental formulas adopted by CEB-FIP, ACI, and KCI rather than the age adjusted effective modulus concept. Twenty-one design variable including the material and geometrical properties of concrete, nonprestressing steel and prestressing steel, and the geometry of the cross section are considered in the sensitivity analysis. The gradients of the stresses and strains needed for the sensitivity assessment are calculated in a closed format. The derived formulation is applied to the T-type section PSC beam with prestressing and nonprestressing steels for the sensitivity analysis. The analytically calculated sensitivity results are compared with those numerically calculated to ensure the validity of the proposed procedure.