• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.25-32
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• 2004

This paper examines the results of full-scale field tests on micropiles and side resistance is evaluated with respect to axial displacements and soil properties. Both cohesive and cohesionless soils are included in this evaluation. For all practical purposes, the developed load-displacement relationship and the geotechnical soil properties for each micropile and soil type can be used to represent the available data well through normalized average values and empirical correlations. There is a significant difference in load-carrying capacity between micropiles and drilled shafts that results primarily from the micropile pressure-grouting installation effects on the state of stress in the ground. The results show that micropiles can have a significant increase of capacity over larger-diameter drilled shafts at shallower depths with D/B < 100 or so. In cohesive soils, the typical increase is on the order of 1.5 with values as high as 2.5. For cohesionless soils, the typical increases are in the range of 1.5 to 2.5 with values as high as 6.

• Journal of Pharmaceutical Investigation
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• v.41 no.3
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• pp.161-171
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• 2011

The objective of the present study is to systematically characterize a linear viscoelastic behavior of petroleum jelly in small amplitude oscillatory shear flow fields correspondent to the rheological ground state. With this aim, using a strain-controlled rheometer, the dynamic viscoelastic properties of commercially available petroleum jelly have been measured at $37^{\circ}C$ (body temperature) over a wide range of angular frequencies at an extremely small strain amplitude of 0.1 %. In this article, the linear viscoelastic behavior was reported in detail and then explained from a structural view-point of petroleum jelly and discussed in depth with respect to the consumer's requirements. Main findings obtained from this study can be summarized as follows : (1) The storage modulus is always greater than the loss modulus over an entire range of angular frequencies studied, meaning that the linear viscoelastic behavior of petroleum jelly is dominated by an elastic nature rather than a viscous nature. (2) Petroleum jelly shows a desirable linear viscoelastic behavior with respect to the consumer's requirements because it is undesirable for the product to flow down from the skin at an initial stage upon contact with the human skin. (3) A fractional derivative model shows an excellent applicability to describe a linear viscoelastic behavior of petroleum jelly. However, this model should be used with a special caution because there exists no physical meaning for the model parameters. (4) A modified form of the Cox-Merz rule gives a good ability to predict the relationship between steady shear flow properties (nonlinear behavior) and dynamic viscoelastic properties (linear behavior) for petroleum jelly.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.62-67
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• 1993

The microscopic origin of nonlinear optical properties of quinoline derivatives have been investigated theoretically using MOPAC-AM1 method. In order to prepare promising nonlinear optical active polymers of polyquinoline derivatives, the optimized positions of strong electron donor and electron acceptor are determined in the heterocyclic ring for the energetically favorable structures. For each compound, the effect of the substituted positions on the microscopic nonlinear coefficients were investigated. Polyquinoline was already evaluated to have outstanding physical and mechanical properties so that its monomeric analogues were designed and synthesized for developing new second and third order nonlinear optical main chain polymers. Using the MOPAC-AM1 method, properties calculated include the intrinsic ground-state dipole moments, the polarizabilities, first and second hyperpolarizabilities under the condition of finite-field $(\omega$ = 0).

• Journal of the Korean GEO-environmental Society
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• v.22 no.6
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• pp.17-26
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• 2021

Ground investigation and result analysis generally used to examine all sorts of structures' subsidence or stability can be classified into sandy soil and cohesive soil, and analysis on the liquid limit of soil is utilized to evaluate the physical properties of ground and types or technical behavior of soil. The most widely used method to analyze liquid limit is Casagrande with which liquid limit can be calculated relatively easily; however, it is fairly difficult to apply it to soil equipped with intermediate properties. Therefore, concerning the properties of soil having the intermediate properties of sedimentary ground, this researcher mixed the clay from Yangsan, Gwangyang, and Busan with sandy soil to make intermediate soil and then carried out the test of consistency limit and also evaluated applicability by using the suggested formula of consistency revision. The sample of intermediate soil was the mixture of clay and sandy soil, and to produce intermediate soil, the content (F_c) of fine soil was applied as 50%, 75%, or 100%. Regarding the physical properties of intermediate soil, to maintain the properties of clay in the natural state, bentonite was added at a fixed rate for controlling the properties of clay, and then, consistency was analyzed. By adopting the formula of consistency revision suggested in advanced research, this author analyzed consistency based on the experiment and consistency based on the suggested formula of revision. Also, about intermediate soil collected at the site, consistency based on the experiment and consistency based on the suggested formula of revision were analyzed comparatively, and about intermediate soil collected, this researcher analyzed particle size and calculated the content (F_c) of fine soil to analyze intermediate soil in diverse conditions. Moreover, about intermediate soil collected at the site, the suggested formula of consistency revision was applied to calculate the compression index, and the compression index based on the experiment and the compression index based on the suggested formula were analyzed comparatively to evaluate the applicability of the suggested formula.

• Geomechanics and Engineering
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• v.20 no.2
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• pp.131-146
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• 2020

Evaluation of earthquake impacts in settlements with a high risk of earthquake occurrence is important for the determination of site-specific dynamic soil parameters and earthquake-resistant structural planning. In this study, dynamic soil properties of Karliova (Bingol) city center, located near to the intersection point of the North Anatolian Fault Zone and the East Anatolian Fault Zone and therefore having a high earthquake risk, were investigated by one-dimensional equivalent linear site response analysis. From ground response analyses, peak ground acceleration, predominant site period, 0.2-sec and 1-sec spectral accelerations and soil amplification maps of the study area were obtained for both near-field and far-field earthquake effects. The average acceleration spectrum obtained from analysis, for a near-field earthquake scenario, was found to exceed the design spectra of the Turkish Earthquake Code and Eurocode 8. Yet, the average acceleration spectrum was found to remain below the respective design spectra of the two codes for the far-field earthquake scenario. According to both near- and far-field earthquake scenarios in the study area, the low-rise buildings with low modal vibration durations are expected to be exposed to high spectral acceleration values and high-rise buildings with high modal vibration durations will be exposed to lower spectral accelerations. While high amplification ratios are observed in the north of the study area for the near-distance earthquake scenario, high amplification ratios are observed in the south of the study area for the long-distance earthquake scenario.

• Earthquakes and Structures
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• v.5 no.1
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• pp.49-65
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• 2013

This article presents the statistical characteristics of elastic floor acceleration spectra that represent the peak response demand of non-structural components attached to a nonlinear supporting frame. For this purpose, a set of stiff and flexible general moment resisting frames with periods of 0.3-3.6 sec. are analyzed using forty-nine near-field strong ground motion records. Peak accelerations are derived for each single degree of freedom non-structural component, supported by the above mentioned frames, through a direct-integration time-history analysis. These accelerations are obtained by Floor Acceleration Response Spectrum (FARS) method. They are statistically analyzed in the next step to achieve a better understanding of their height-wise distributions. The factors that affect FARS values are found in the relevant state of the art. Here, they are summarized to evaluate the amplification and/or reduction of FARS values especially when the supporting structures undergo inelastic behavior. The properties of FARS values are studied in three regions: long-period, fundamental-period and short-period. Maximum elastic acceleration response of non-structural component, mounted on inelastic frames, depends on the following factors: inelasticity intensity and modal periods of supporting structure; natural period, damping ratio and location of non-structural component. The FARS values, corresponded to the modal periods of supporting structure, are strongly reduced beyond elastic domain. However, they could be amplified in the transferring period domain between the mentioned modal periods. In the next step, the amplification and/or reduction of FARS values, caused by inelastic behavior of supporting structure, are calculated. A parameter called the response acceleration reduction factor ($R_{acc}$), has been previously used for far-field earthquakes. The feasibility of extending this parameter for near-field motions is focused here, suggested repeatedly in the relevant sources. The nonlinearity of supporting structure is included in ($R_{acc}$) for better estimation of maximum non-structural component absolute acceleration demand, which is ordinarily neglected in the seismic design provisions.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.21-28
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• 2006

This paper presents both experimental and analytical studies for the development of an ECC(Engineered Cementitious Composites) using ground granulated blast furnace slag(slag). This material has been focused on achieving moderately high composite strength while maintaining high ductility, represented by strain-hardening behavior in uniaxial tension. In the material development, micromechanics was adopted to properly select optimized range of the composition based on steady-state cracking theory and experimental studies on matrix, and interfacial properties. A single fiber pullout test and a wedge splitting test were employed to measure the bond properties of the fiber in a matrix and the fracture toughness of mortar matrix. The addition of the slag resulted in slight increases in the frictional bond strength and the fracture toughness. Subsequent direct tensile tests demonstrate that the fiber reinforced mortar exhibited high ductile uniaxial tension behavior with a maximum strain capacity of 3.6%. Both ductility and tensile strength(~5.3 MPa) of the composite produced with slag were measured to be significantly higher than those of the composite without slag. The slag particles contribute to improving matrix strength and fiber dispersion, which is incorporated with enhanced workability attributed to the oxidized grain surface. This result suggests that, within the limited slag dosage employed in the present study, the contribution of slag particles to the workability overwhelms the side-effect of decreased potential of saturated multiple cracking.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.295-307
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• 2002

In the Nakdong River plain a very thick clayey soils are covered widely. Since the early 1990's, some huge reclamation projects have been performed for the development of industrial and residential complexes and so on. Despite a large number of soil investigations have been carried out for the projects, the geotechnical properties have never been elucidated well, so that the settlements of the ground due to the mischaracterized properties were greatly underestimated. Therefore, it has been needed to evaluate definitely the characteristics of the clayey soils, particularly for the compressibility characteristics to help understand the settlement behavior. For the compressibility characteristics of the Pusan clays, physical index and consolidation tests were conducted on the reconstituted and undisturbed samples. Using the result of physical index, the Pusan clays could be divided into two different units, which have different depositional environments. According to the concepts of Burland (1990) and Nagaraj et. al. (1990), the intrinsic state line and field compression curve of the Pusan clays could be established. It could be found from their concepts that the Pusan clays are under the cemented and young normally consolidated state and largely consisted of two units. The cementation of the clays was as well identified by compression index ratio (Tsuchida et. al.,1991) and sensitivity (Leroueil et. al.,1983).

• Korean Institute of Interior Design Journal
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• v.27 no.3
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• pp.90-99
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• 2018

The purpose of this study is to study how F.L. Wright reflected the climatic properties and materials of the region into creative ways of designing his architecture. The research method examined the design methods and use of materials by Wright in existing research literature and compares the space plans of housing works in Arizona. The research results will be summarized as follows : 1) For two-story houses, pilotis was used to avoid the hot air and the walls on the ground floor were often planned as thick wall. 2) In the fifties, F.L. Wright's design method changed in a circle from the vertical and horizontal lines. 3) F.L.Wright's Architectural form concepts and design concepts were extracted from local symbolic forms and natural forms. 4) F.L.Wright avoided Arizona's direct light but Indirect sunlight enters into the interior space. 5)External space was expressed as a closed space, while internal space was expressed as an open space. It's like an organic space. 6) Most of the housing materials used are stone and cement from rough deserts, and wood with low heat conductivity and thick concrete blocks to prevent the sunlight from rising above.

• Journal of the Korean Magnetics Society
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• v.1 no.1
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• pp.6-11
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• 1991

In order to investigate electronic and magnetic properties of permanent magnets, we have performed self-consistent electronic structure calculations on compounds of rare-earth and transition metals, such as $SmCo_{5},\;NdB_{6},\;NdFe_{5},\;NdFe_{4}B$. Employing the local density LMTO(linearized muffin tin orbital) band method, we have obtained the ground state parameters, such as band structures, density of states, Stoner parameters, and magnetic moments. We have also investigated interactions between d,f-electrons of Nd, Sm rare-earths and d-electrons of Fe, Co transition metals, and the s,p electrons of boron and explored effects of such interactions on the bonding mechanism and the electronic and magnetic structures in these rare-earth compounds.