• Korea-Australia Rheology Journal
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• v.12 no.3_4
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• pp.151-155
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• 2000

A semiconducting poly(naphthalene quinone) radical (PNQR) was synthesized from Friedel-Craft acylation between naphthalene and phthalic anhydride and used as dispersing particles of a dry-base electrorheological (ER) material in silicone oil. Under an applied electric field (E), the dynamic yield stress (${\tau}_{dyn}$) of this ER fluid, obtained from a steady shear experiment with a controlled shear rate mode, was observed to increase with $E^{1.45}$ Based on this relationship, we propose a universal correlation curve for shear viscosity, which is independent of E using a scaling analysis.

• Journal of the Korean Chemical Society
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• v.68 no.1
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• pp.20-24
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• 2024

This article presents the advantages of utilizing gossypol and its derivatives as reagents for iron (III) (Fe (III)) ions. A novel spectrophotometric method has been developed for the determination of Fe (III) using gossypol derivatives in the presence of a universal buffer solution. Optimal conditions have been identified, and the composition and stability constants of the Fe (III) complex with gossypolacetic acid have been determined.

• Journal of architectural history
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• v.26 no.4
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• pp.35-44
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• 2017

The purpose of this study is to classify three-Kan hipped and gable-roofed Buddhist temples with the construction of their eave curve of part chunyeo and examine the characteristics and causes. The conclusions have been drawn as follows: First, there are largely three ways to secure symmetry in eave curve of part chunyeo. One is to obtain symmetry in eave curve of part chunyeo by making the size of eaves curves on well sides the same and forming symmetric curves in the front section along with the side roof and then forming the straight line in the central part (hereinafter referred to as the long straight line section method). The second is a method to enlarge eaves curves in the front and form eaves curves on the roof section to be symmetric (hereinafter referred to as the front is larger than side eaves curves method). The third is the method to make eaves curves in the roof section to be symmetric by adjusting the roof length and making difference between the front and side roof's length minimum (hereinafter referred to as the roof length-controlling method). Second, there are 16 cases applying two or more methods, and they are the mainstream. Third, there are 12 cases applying the front is larger than side eaves curve method and roof length-controlling method both, which seems to be the most universal. To sum up, they secured symmetry in roof edges considering the construction of seonjayeon and pyeongyeon according to the size of the structure, recognition on the directions of entrance into the area of the building, forms of planes, harmony with structures around, recognition on roof curves in accordance with the size, and also structural faults in the chunyeo part.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.474-479
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• 2003

This paper addresses the problem of B-spline surface interpolation to serial contours, where the number of points varies from contour to contour. A traditional lofting approach creates a set of B-spline curves via B-spline curve interpolation to each contour, makes them compatible via degree elevation and knot insertion, and performs B-spline surface lofting to get a B-spline surface interpolating them. The approach tends to result in an astonishing number of control points in the resulting B-spline surface. This situation arises mainly from the inevitable process of progressively merging different knot vectors to make the B-spline curves compatible. This paper presents a new approach for avoiding this troublesome situation. The approach includes a novel process of getting a set of compatible B-spline curves from the given contours. The process is based on the universal parameterization [1,2] allowing the knots to be selected freely but leading to a more stable linear system for B-spline curve interpolation. Since the number of control points in each compatible B-spline curve is equal to the highest number of contour points, the proposed approach can realize efficient data reduction and provide a compact representation of a B-spline surface while keeping the desired surface shape. Some experimental results demonstrate its usefulness and quality.

• Water for future
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• v.26 no.3
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• pp.63-74
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• 1993

The objectives of this paper were to apply the gross erosion and sediment delivery ration method for estimating sediment deposits at selected reservoirs of various sizes, and to define their trap efficiencies. Twenty reservoirs that have sediment survey data were selected and the annual average soil losses from subareas within each watershed were estimated using the Universal Soil Loss Equation (USLE). The gross erosion was defined fro the soil losses and estimated channel erosion. By applying the sediment delivery ratios that were defined from an empirical relationship with watershed areas, net incoming sediment yields at reservoirs were defined. Trap efficiencies were applied, sediment deposits estimated, and compared to the surveyed data. The results were in general agreement with the data. Trap efficiencies were also defined from the ratios of sediment deposits to incoming sediment yields. They were within 20% differences from Brune curve, which indicates that Brune curve may be applied for irrigation reservoirs. And an empirical relationship was proposed, that appeared more reliable for estimating trap efficiencies for typical irrigation reservoirs.

• Smart Structures and Systems
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• v.23 no.6
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• pp.565-577
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• 2019

One of the most effective countermeasures for mitigating cable vibration is to install mechanical dampers near the anchorage of the cable. Most of the dampers used in the field are so-called passive dampers where their parameters cannot be changed once designed. The parameters of passive dampers are usually determined based on the optimal damper force obtained from the universal design curve for linear dampers, which will provide a maximum additional damping for the cable. As the optimal damper force is chosen based on a predetermined principal vibration mode, passive dampers will be most effective if cable undergoes single-mode vibration where the vibration mode is the same as the principal mode used in the design. However, in the actual engineering practice, multi-mode vibrations are often observed for cables. Therefore, it is desirable to have dampers that can suppress different modes of cable vibrations simultaneously. In this paper, MR dampers are proposed for controlling multi-mode cable vibrations, because of its ability to change parameters and its adaptability of active control without inquiring large power resources. Although the highly nonlinear feature of the MR material leads to a relatively complex representation of its mathematical model, effective control strategies can still be derived for suppressing multi-mode cable vibrations based on nonlinear modelling, as proposed in this paper. Firstly, the nonlinear Bouc-wen model is employed to accurately portray the salient characteristics of the MR damper. Then, the desired optimal damper force is determined from the universal design curve of friction dampers. Finally, the input voltage (current) of MR damper corresponding to the desired optimal damper force is calculated from the nonlinear Bouc-wen model of the damper using a piecewise linear interpolation scheme. Numerical simulations are carried out to validate the effectiveness of the proposed control algorithm for mitigating multi-mode cable vibrations induced by different external excitations.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.345-349
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• 1985

The textural properties of acorn flour gels were investigated with the variations in the concentraction, storage time and storage temperature by the use of Instron Universal Testing Machine. The experimental design was $3^3$ factorial experiment. TPA curves of acorn flour gels showed two sharp peaks in the first bite and no negative peak. The hardness and brittleness of acorn flour gels were very significantly affected by concentration, storage time and storage temperature. For the height difference between first peak and second peals, the main effects for concentration and storage temperature were very significant and the main effect for storage time was not negligible. For bend, the effect of concentration was more significant than the effect of storage temperature, and storage time effect was negligible. Springiness was affected only by the concentration.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.197-200
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• 2016

Background: Wedge filters are commonly used in radiation oncology for eliminating hot spots and creating a uniform dose distribution in optimizing isodose curves in the target volume for clinical aspects. These are some limited standard physical wedges ($15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$),or creating an arbitrary wedge angle, like motorized wedge or dynamic wedge,${\ldots}$ The new formulation is presented by the combination of wedge fields for determining an arbitrary effective wedge angles. The isodose curves also are derived for these wedges. Materials and Methods: we performed the dosimetry of Varian Clinac 2100C/D with Scanditronix Wellhofer water blue phantom, CU500E, OmniPro - Accept software and 0.13cc ionization chamber for 6Mv photon beam in depth of 10cm (reference depth) for universal physical wedges ($15^{\circ}$, $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$) and reference field $10.10cm^2$. By combining the isodose curve standard wedge fields with compatible weighting dose for each field, the effective isodose curve is calculated for any wedge angle. Results: The relation between a given effective wedge angle and the weighting of each combining wedge fields was derived. A good agreement was found between the measured and calculated wedge angles and the maximum deviation did not exceed $3^{\circ}$. The difference between the measured and calculated data decreased when the combined wedge angles were closer. The results are in agreement with the motorized single wedge appliance in the literature. Conclusions: This technique showed that the effective wedge angle that is obtained from this method is adequate for clinical applications and the motorized wedge formalism is a special case of this consideration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.11 s.254
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• pp.1417-1424
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• 2006

In order to evaluate variation of fatigue life of mechanical components including engineering plastics, it is important to estimate probabilistic strain-life curves to accurately define the variation of fatigue characteristics. This paper intends to provide new assessment of P-$\varepsilon$-N (probabilistic strain-life curves) for considering the variation of fatigue characteristics in polyacetal. The fatigue strain controlled tests were conducted under constant 50% humidity and room temperature condition by a universal testing machine at strain ratio, R=0. A practical procedure is introduced to evaluate probabilistic strain-life curves. Three probabilistic distributions were used for generating P-$\varepsilon$-N curves such as normal, 2-parameter and 3-parameter Weibull. In this study, 3-parameter Weibull distribution was found to be most appropriate among assumed distributions when the probability distributions of the fatigue characteristic were examined using chi-square and Kolmogorov-Smirnov test. The more appropriate P-$\varepsilon$-N curves for these materials are generated by the proposed method considering 3-parameter Weibull distribution.

• Steel and Composite Structures
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• v.25 no.3
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• pp.327-335
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• 2017

To gain more knowledge of aluminum foam sandwich structure and promote the engineering application, aluminum foam sandwich consisting of 7050 matrix aluminum foam core and 304 stainless steel face-sheets was studied under three-point bending by WDW-T100 electronic universal tensile testing machine in this work. Results showed that when aluminum foam core was reinforced by 304 steel face-sheets, its load carrying capacity improved dramatically. The maximum load of AFS in three-point bending increased with the foam core density or face-sheet thickness monotonically. And also when foam core was reinforced by 304 steel panels, the energy absorption ability of foam came into play effectively. There was a clear plastic platform in the load-displacement curve of AFS in three-point bending. No crack of 304 steel happened in the present tests. Two collapse modes appeared, mode A comprised plastic hinge formation at the mid-span of the sandwich beam, with shear yielding of the core. Mode B consisted of plastic hinge formation both at mid-span and at the outer supports.