• Journal of the Korean Magnetics Society
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• v.9 no.5
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• pp.234-238
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• 1999

Lithium ferrites are prominent in the element of microwave frequency communication core and high frequency memory core because of their low coercivity and the high squareness ratio. This paper reports primarily the development of lithium ferrites with the low coercivity and high squareness ratio. The materials with $Li_{0.48-0.5x}Bi_{0.02}Ni_{0.04}Zn_xFe_{2.46-0.5x}O_4$ (x = 0,0.01, 0.02, 0.03) have been prepared to investigate the physical properties. The addition of ZnO gave raised maximum induction $(B_m)$ and decreased coercive force $(H_c)$, but the squareness ratio $(R\;=\;B_m/B_r)$ was decreased. The specimen of squareness ratio R=0.82, coercive force $H_c=\;1.80\;Oe$ was obtained for $Li_{0.48-0.5x}Bi_{0.02}Ni_{0.04}Zn_xFe_{2.46-0.5x}O_4$ (X=0) sintered at 105$0^{\circ}C$. Also the sample of squareness ratio R = 0.75, coercive force $H_c=\;1.70\;Oe$ for $Li_{0.48-0.5x}Bi_{0.02}Ni_{0.04}Zn_xFe_{2.46-0.5x}O_4$ (X = 0) sintered at 110$0^{\circ}C$ was measured. The Tc was obtained 463$^{\circ}C$ and the Br of environmental temperature variation was stable.

• Korean Journal of Agricultural Science
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• v.2 no.1
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• pp.143-149
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• 1975

To obtain some basic informations on the breeding of Kudzu, 42 individuals were selected and their morphological characteristics were investigated and analyzed. The shape of leaves was classified as 4 types and area of leaves into 5 steps. Internode length was distributed between 13 cm and 37 cm. Significant correlations were recognized between petiole and leaf area, between internode length and internode diameter and between internods diameter and leaf area.

• Journal of Sericultural and Entomological Science
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• no.12
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• pp.13-16
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• 1970

The studies were intended to clarify the correlations between the characters and the influences upon yield of mulberry trees. The analysis of covariance was used to obtain the genotypic correlations and phenotypic correlations among the eight characters namely branch length, node number, branch diameter, branch number per stock, total branch weight, old branch weight, new shoot and leaf weight, etc., and path-coefficients were calculated by Dewey's method (5). The results obtained are summarized as follows： 1. Genotypic correlations were slightly higher than the corresponding phenotypic correlations between tile characters as shown in Table 1. It could be indicated that hight leaf yield was genetically correlated with almost all characters studied except branch diameter. 2. Leaf yield of mulberry trees was mainly associated with the characters such as node number per branch, total branch weight and old branch weight, etc. 3. Branch length, branch diameter, branch number per stock and new shoot weight had little direct influence upon yield but it had rather considerable indirect in fluence upon yield by increasing the node number and total branch weight per stock. As a result, it can be concluded that total branch weight is primarily determined by branch number per stock and old branch weight, and in turn the leaf yield of mulberry trees is secondary determined by the node number by increasing the branch diameter and length which are positively correlated with branch number per stock and new shoot weight of mulberry trees.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.189-190
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• 2015

Slim Floor construction method has to increase the available surface area thereby reducing the depth beams and slab. In addition, In this study compostie beam assembly of plates, square-shape steel pipe and deck plate. So workabiltiy is superior to the upper concrete possible without formwork. In the present study is strength test in progress in development slim floor composite beam used plate and perforated square shape steel pipe and obtained anlysis and conclustion of the experimental results.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.67-76
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• 2006

In this paper the moment transfer efficiency of a web and the strain concentration at the RHS (Rectangular Hollow Section) column-to-steel beam connections was evaluated. Initially, non-linear finite element analysis of five bare steel beam models was conducted. The models were designed to have different detail at their beam-to-column connection, so that the flexural moment capacity was different respectively. Analysis results showed that the moment transfer efficiency of the analytical model with RHS-column was poor when comparing to model with WF(Wide Flnage)-column due to out-of-plane deformation of the RHS-column flange. The presence of scallop and thin plate of RHS column was also a reason of the decrease of moment transfer efficiency, which would result in a potential fracture of the steel beam-to-column connections. Analytical results were compared with the previous experimental results. The analytical and the previous experimental results showed that the strain concentration was inversely proportional to the moment transfer efficiency of a beam web and the deformation capacity of connection was poor as their moment transfer efficiency degrades. Further finite element analyses of composite beam with a floor slab revealed that the neutral axis moved toward the top flange and the moment transfer efficiency of a beam web decreased, which led to premature failure of the connection.

• Journal of Korean Society of Steel Construction
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• v.13 no.6
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• pp.715-723
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• 2001

This paper represents the behavior of CFT column to H-beam full-scale connection with external T-stiffener. 6 specimens whose T-stiffeners which are compounded of vertical element and horizontal element were made under the parameter of the strength ratio of each elements(vertical element and horizontal element in T-stiffener) to the beam full plastic moment. The analysis-parameters demonstrated in the base of the data that we get in experiment are strength stiffness, and plastic rotational capacity. All of specimen showed stable hysteretic behavior, and the horizontal element is more critical than vertical element in strength and stiffness. The mean beam plastic rotation of all specimen except the TS-2 specimen is 2.97% rad.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.247-255
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• 2004

An experimental program was undertaken to develop seismic retrofit methods of existing steel moment connections with floor slab for improved seismic performance. Five full-scale composite specimens were tested under cyclic loading. Conventional through-diaphragm connections [please check this; no search results were found for through-diaphragm connections] composed of square-tube column and H-beam were retrofitted by adding either a bottom-flange dogbone (RBS) or an improved welded horizontal stiffener at the beam bottom flange. The effectiveness of the proposed retrofit connections schemes was evaluated. The specimen retrofitted using the RBS concept at the bottom flange showed poor connection ductility. In contrast. specimens with the proposed horizontal stiffener details exhibited improved connection ductility.

• Journal of Forest and Environmental Science
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• v.3 no.1
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• pp.17-20
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• 1983

Through 7-year experiment in Korean pine stand since 1975, the followings are obtained as the results of investigation in several characters: 1. In total volume, the highest value after 1980 was shown in the control plot, which was the second one for 4 years, 1975 to 1979. 2. In the increment ratios of height, diameter at breast height(D. B. H.), and individual volume, the plot with the intermittent period of 3 years showed the higher values than any other plot.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.253-261
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• 1998

The buckling length of exterior beam-columns of the first floor in moment resisting steel frames with weak beams is uncertain when plastic hinges occur at the ends of weak beams due to seismic loads. The objective of this study is to investigate the buckling strength of concrete-filled tubular beam-columns and to suggest the reduced buckling length of them to apply to the beam-column design code. The exterior beam-columns are modelized with horizontal displacement restraint springs. Their strength and reduced buckling length are evaluated by numerical analysis.

• Journal of the Korean Magnetics Society
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• v.22 no.2
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• pp.42-44
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• 2012

We have studied a means to control the composition of nickel-iron thin films. By changing current and voltage applied to a electroplating electrolyte we could manipulate the relative concentration of nickel and iron in the thin films, which caused variations of coercivity, squareness, and saturation magnetic field. As we increase the content of iron in the thin films by using potentiostatic and galvanostatic plating, the grain size was increased and the coercivity was reduced.