• Composites Research
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• v.26 no.2
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• pp.99-104
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• 2013

The design of composite joint is important research area because they are often the weakest areas in composite structures. In this paper, the specimens with three paste thickness (0.2 mm, 0.6 mm, 4 mm) were manufactured in secondary bonding method and tested in two different loading direction condition. Also, the failure index of the L-type stiffener was calculated by the finite element method and compared with experimental results.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.7-13
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• 1999

This paper propose a fuzzy regression method using fuzzy neural networks when a membership value is attached to each input -output pair. First, an architecture of fuzzy neural networks with fuzzy weights and fuzzy biases is shown. Next, a cost function is defined using the fuzzy output from the fuzzy neural network and the corresponding target output with a membership value. A learning algorithm is derived from the cost function. The derived learning algorithm trains the fuzzy neural network so that the level set of the fuzzy output includes the target output. Last, the proposed method is applied to the quality evaluation problem of injection molding

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.225-227
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• 2011

The geometrically sub-scaled wall-injection test model was employed to visualize interactions of internal flow of a solid rocket motor equipped fin/slot grain and submerged nozzle. Symmetric vortex and circumferential flow patterns were visualized.

• Journal of the Korean Geotechnical Society
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• v.30 no.2
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• pp.65-76
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• 2014

For soil improvement, sand mats or sand compaction piles are often constructed on soft marine clays. In such cases, some amounts of sand and clay are inevitably mixed. Sand or gravel often exists in the weathered soils near the slope surface. This research investigates the effect of mixing sand content on consistency limits and shear strength of clays. Firstly, sand was mixed with kaolinite or bentonite at 0, 9, 17, 23, 29, 33, 50% and then liquid and plastic limits were measured. Both plastic and liquid limits decreased as a sand content increased. The water content of clay-sand mixtures with different sand content increased by 10% or 20% step by step and then their undrained shear strength was measured using a portable vane shear device called Torvane. For all cases, undrained shear strength of clay-sand mixtures decreased rapidly until reaching a certain value. Their state changed from undrained to drained state gradually as the sand content increased, which caused their undrained shear strength to decrease. On the other hand, a series of direct shear tests were also conducted on such clay-sand mixtures to investigate the effect of sand content on cohesion and angle of internal friction. It was found from clay-sand mixtures that their cohesion decreased but angle of internal friction increased as the sand content increased.

• Korean Journal of Poultry Science
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• v.38 no.3
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• pp.197-204
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• 2011

To investigate the effects of Cordyceps ochraceostromat, silkworm cocoon and conjugated linoleic acid (CLA) addition on the quality of cremi during storage, this study was conducted. Cremis were prepared using a 20% spent layer breast recovered protein to replace Alaska pollack with the addition of 0.1% silkworm cocoon powder (T1), 0.05% silkworm cocoon powder + 0.05% Cordyceps ochraceostromat powder (T2), and 0.05% silkworm cocoon powder + 0.05% CLA. All manufactured cremis were vacuum-packaged, stored at $10{\pm}1^{\circ}C$ and finally evaluated for their quality on 0, 2, 4 and 6 weeks of storage. The pH, whiteness, gel strength and breaking force of cremis from T2 were higher than those of samples derived from either T1 or T3. However, cremis from T2 showed low shear force values when compared to other cremis (p<0.05). Therefore, the results indicate that cremis contained 0.05% silkworm cocoon powder and 0.05% Cordyceps ochraceostromat combination (T2) may be recommendable to induce customers to buy, thereby, it may be beneficial to both manufacturers and consumers in market.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.9-14
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• 2017

In the present work, a mechanical performances under cyclic loading in RC (Reinforced Concrete) beams with normal steel and FRPH (Fiber Reinforced Plastic Hybrid) bar are investigated. For the work, RC beam members with $200{\times}200{\times}2175mm$ of geometry and 24 Mpa of design strength are prepared, and 4-point-bending tests are performed for evaluation of cracking, yielding, and ultimate loads. Through static loading test, 48.9kN and 36.0 kN of yielding loads are measured for normal RC and FRPH beam, respectively. They have almost same ultimate load of 50.0 kN. Typical tension hardening behavior is observed in FRPH beam, which is caused by the behavior of FRPH bar with tension hardening. In cyclic loading conditions, FRPH beam has more smaller crack width and scattered crack pattern, and it shows more elastic recovery than normal RC beam. The energy dissipation ratio in FRPH beam is 0.83, which is greater than 0.62 in normal RC beam and it shows more effective resistance to cyclic loadings.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.114-120
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• 1997

Frequencies and the types of abnormal vertebrae in the juvenile of five cyprinid fishes collected from the Kumho River during 1995 and 1996 were examined. Types of vertebral anomalies in investigated species were spinal curvature, fused vertebrae, helical sutures of cetera and abnormal vertebrae with one or two additional spines. The frequencies and the types of vertebral anomalies were different among the species. Of all the examined species, the type with one or two additional spines showed the highest frequencies, 11.72~12.11%. The frequencies of fused vertebrae was 4.45~7.68%. Thes two types of vertebral anomalies were observed in all species. Among the several types of fused vertebrae, the frequencies of double fused vertebrae were higher than those of other types. Also, the incidence of fused vertebrae located in the caudal region of vertebral column was much higher than that in other regions. The percentages of spinal curvature and helical sutures of vertebrae in the investigated species were 0.02~0.15% and 0.02%, respectively. Among the examined specimens, vertebral anomalies include fused vertebrae and one or two additional spines were shown in the three species, Korean slender gudgeon (Squalidus gracilis majimae), False dace (Pseudorasbora parva) and Crucian carp (Carassius auratus). In addition to the two vertebral anomalies, spinal curvature was shown in the Korean gudgeon (Squalidus chankaensis tsuchigae). Dark chub (Zacco temmincki) had fused vertebrae, one or two additional spines, spinal curvature, and helical sutures of vertebrae. This species has the most variable vertebral anomalies. Frequencies of fused vertebrae and one or two additional spines in the all tested fishes were not related with their standard lengths measured. However, spinal curvature and helical sutures of vertebrae were shown only in the specimens smaller than 20mm in standard length.

• The Korean Journal of Mycology
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• v.11 no.4
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• pp.169-175
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• 1983

For the classification of 531 isolates of Fusarium moniliforme from infected rice plants, five criteria were employed for clarifying the mycological difference from I to IV based on host symptoms, conidial formation, septate of macroconidia, color of mycelium on the culture, and fungicide response. Four strains I, II, III, and IV were detected and Strain IV was the most prevalent one. Based on mycological characteristics, macroconidia with 6 or 7 septate were mostly produced by Strains I and II. Four septate macroconidia were mostly formed by Strain III while Strain IV mostly formed 3 septate macroconidia. Strain I was reddish purple (5RP 5/4) on both the bottom and the surface of the media. Strain II produced reddish purple(5RP 3/2) on both the bottom and the surface of the media. Strain I produced mostly macroconidia in pionnotes on the media surface while Strain II produced mostly microconidia in pionnotes on the media surface. Both of Strain III and IV produced mostly macroconidia in sporodochia on the surface of the mycelium. Strain IV was less reduction of germination and caused abnormal elongation of all parts of the plants, but did not kill the plants in nursery boxes. Strain III killed fewer plants than Strain IV. As above results, isolates of F. moniliforme were classified into four strains I, II, III, and IV, on the basis of five criteria.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.53-60
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• 2024

Compressive strength in concrete has many affecting parameters and varies with exposure conditions. Although the concrete has same mix proportions, its properties are different with exposure conditions, and sea-environment can be classified into three groups such as tidal, atmospheric, and sea submerged region particularly. In this study, compressive strength was evaluated on 7-year-cured concrete and the results from previous equations (KDS, ACI, CEB, and JSCE) were compared with them. Furthermore the strength and carbonation progress were evaluated on concrete cured for 7 years exposed to three different sea environment. Three levels of w/c (water to cement) ratio (0.37, 0.42, and 0.47) and three different exposure conditions (tidal, atmospheric, and submerged) were considered. The results from wet-cured condition are all higher than those from the previously proposed equations, and the results from different sea exposure conditions (tidal, atmospheric, and submerged region) were lower than those from wet-cured condition. A reduction of strength was evaluated with increasing w/c ratio and the minimum strength was evaluated in the sea-submerged conditions. Several experimental constants applicable to the previous equations were obtained from regression analysis since the strength change with w/c ratios were not considered in those equations. Regarding carbonation depth with different exposure conditions, higher carbonation depth clearly was observed with increasing w/c ratios, and evaluated in the order of atmospheric, submerged, and tidal region. Considerable carbonation depth was observed in submerged and tidal region due to sulfate ion and dissloved carbon dioxide as well.