• Tribology and Lubricants
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• v.29 no.6
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• pp.360-365
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• 2013

In this study, sliding wear tests were conducted to investigate the effects of tempered hardness on the sliding wear behavior of bearing steel. At a sliding speed of 0.3 m/s, the wear resistance of bearing steel with a tempered hardness of HRC 54 was superior to that with HRC 62. It was found that bearing steel with HRC 54 showed a strong tendency for the occurrence of oxidation wear at that speed, compared to that with HRC 62. This would be due to the troostitic structure of bearing steel with HRC 54, which is highly susceptible to corrosion. In this context, it is considered that sliding wear behavior could be affected by the corrosion resistance of the material.

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.301-301
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• 1999

No Abstract, See Full Text

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.323-330
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• 2017

Emotion in early childhood has been observed to make an important effect on behavioral development. The teacher has coached to develop good behavior based on considering emotional response rather than rational response. This study was to determine significance of emotional coaching for behavior development according emotion recognized by non-verbal measurement system developed specially in this study. The participants were 44 people and were asked to study in four experimental situation. The experiment was designed to four situation such as class without coaching, behavioral coaching, emotion coaching, and emotion coaching based on emotional recognition system. The dependent variables were subjective evaluation, behavioral amplitude, and HRC (Heart Rhythm Coherence) of heart response. The results showed the highest positive evaluation, behavioral amplitude, and HRC at emotion coaching based on emotional recognition system. In post-doc analysis, the subjective evaluation showed no difference between emotion coaching and system based emotion coaching. However, the behavioral amplitude and HRC showed a significant response between two coaching situation. In conclusion, quantitative data such as behavioral amplitude and HRC was expected to solve the ambiguity of subjective evaluation. The emotion coaching of teacher using emotional recognition system was can be to improve positive emotion and psychological stability for children.

• Steel and Composite Structures
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• v.31 no.5
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• pp.453-467
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• 2019

Portal frame structures, made up of cold-formed steel trusses, are increasingly being used for lightweight building construction. A novel pin-jointed moment connector, called the Howick Rivet Connector (HRC), was developed and tested previously in T-joints and truss assemblage to determine its reliable strength, stiffness and moment resisting capacity. This paper presents an experimental study on the HRC, in moment resisting cold-formed steel trusses. The connection method is devised where intersecting truss members are confined by a gusset connected by HRCs to create a rigid moment connection. In total, three large scale experiments were conducted to determine the elastic capacity and cyclic behaviour of the gusseted truss moment connection comprising HRC connectors. Theoretical failure loads were also calculated and compared against the experimental failure loads. Results show that the HRCs work effectively at carrying high shear loads between the members of the truss, enabling rigid behaviour to be developed and giving elastic behaviour without tilting up to a defined yield point. An extended gusset connection has been proposed to maximize the moment carrying capacity in a truss knee connection using the HRCs, in which they are aligned around the perimeter of the gusset to maximize the moment capacity and to increase the stability of the truss knee joint.

• Journal of Animal Science and Technology
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• v.58 no.2
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• pp.9.1-9.5
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• 2016

Background: Literature is lacking on the effects of feeding by-product feed (BF)-based silage on rumen fermentation parameters, nutrient digestion and nitrogen (N) retention in sheep. Therefore, this study was conducted to determine the effect of replacing rye straw with BF-based silage as a roughage source on ruminal parameters, total-tract apparent nutrient digestibility, and N balance in sheep. Methods: The by-product feed silage was composed of spent mushroom substrate (SMS) (45 %), recycled poultry bedding (RPB) (21 %), rye straw (11 %), rice bran (10.8 %), corn taffy residue (10 %), protected fat (1.0 %), bentonite (0.6 %), and mixed microbial additive (0.6 %). Six sheep were assigned randomly to either the control (concentrate mix + rye straw) or a treatment diet (concentrate mix + BF-based silage). Results: Compared with the control diet, feeding a BF-based silage diet resulted in similar ruminal characteristics (pH, acetate, propionate, and butyrate concentrations, and acetate: propionate ratio), higher (p < 0.05) ruminal NH3-N, higher (p < 0.05) ether extract digestibility, similar crude protein digestibility, lower (p < 0.05) dry matter, fiber, and crude ash digestibilities, and higher (p < 0.05) N retention (g/d) Conclusion: The BF-based silage showed similar energy value, higher protein metabolism and utilization, and lower fiber digestion in sheep compared to the control diet containing rye straw.

• Journal of Microbiology and Biotechnology
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• v.20 no.5
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• pp.942-945
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• 2010

The ability of the human fungal pathogen Candida albicans to undergo the morphological transition from a single yeast form to pseudohyphal and hyphal forms in response to various conditions is known to be important for its virulence. Many studies have shown the pharmacological effects of resveratrol, a phytoalexin polyphenolic compound. In this study, we investigated the antifungal activity of resveratrol against C. albicans. Both yeast-form and mycelial growth of C. albicans were inhibited by resveratrol. In addition, normal filamentation of C. albicans was affected and yeast-to-hypha transition under serum-, pH-, and nutrient-induced hyphal growth conditions was impaired by resveratrol.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.69-71
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• 2000

군집화는 데이터 집합을 유사한 데이터 개체들의 군집들로 분할하여 데이터 속에 존재하는 의미 있는 정보를 얻는 과정이다. 대부분의 군집화 기법들은 비교적 적은 양의 데이터를 대상으로 한 것이고 다차원 대용량의 데이터 처리에 관한 문제는 다루지 않고 있어서 데이터 마이닝을 위한 군집화 기법으로는 부적절하다. 따라서 본 논문을 통해 대용량의 데이터에 적용할 수 있는 새로운 군집화 알고리즘인 계층적 대표값 군집화(HRC) 기법을 제안한다. HRC는 자기조직화지도와 계층적 군집화 기법을 접목한 하이브리드 방법으로 두 단계에 거쳐 군집화를 수행한다. 첫 번째 단계에서 자기조직화지도를 통해 데이터를 요약하고, 두 번째 단계에서 요약된 대표값 정보만을 가지고 계층적인 군집화를 수행한다. 또한, 두 번째 단계의 계층적 군집화 적용시 양질의 군집을 발견하기 위해 군집간의 유사도를 측정하는 새로운 척도를 고안하였다. 그리고 실험을 통해 HRC와 기존 군집화 알고리즘이 발견한 군집의 질을 비교하여 성능을 평가했다.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.1
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• pp.27-34
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• 2001

The effects of pre-heat treatment(Q/T) on microstructure and hardness of STD11 and STD61 tool steel nitrided by micro-pulse plasma were investigated. The quenching temperature for obtaining matrix hardness of STD11 and STD61 steel on range of HRC 50 to HRC 60 desired for machine parts is about $1070^{\circ}C$ and $1020^{\circ}C$ respectively. The hardness of STD11 and STD61 quenched at the temperature was HRC 63 and HRC 56 respectively. The nitrided case depth of STD11 and STD61 nitrided at $550^{\circ}C$ for 5 hours was independent of pre-heat treatment condition and the depth was approximately $100{\mu}m$. However, hardness and compactness of nitrided layer on Q/T treated specimen were higher than the annealed specimen. The case depth increased linearly with the increase of nitriding temperature, however, the hardness of nitrided layer decreased with the increase of temperature. Phase mixture of ${\gamma}-Fe_4N$ and ${\varepsilon}-Fe_{2-3}N$ was detected by XRD analysis in the nitrided layer formed at the optimum nitriding condition. The optimum nitriding temperature was approximately $490^{\circ}C$ which was $10^{\circ}C$ lower than the tempering temperature for preventing softening behavior of STD11 and STD61 matrix during nitriding process and the surface hardness of nitrided layer obtained by optimum pre-heat treatment condition was about Hv1400.

• The Plant Pathology Journal
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• v.15 no.1
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• pp.21-27
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• 1999

Nonpathogenic mutants of Xanthomonas campestris pv. glycines were generated with Omegon-Kim to isolate genes essential for pathogenicity and inducing hypersensitive response (HR). Three nonpathogenic multants and two mutants showing slow symptom development were isolated among 1,000 colonies tested. From two nonpathogenic mutants, 8-13 and 26-13, genes homologous to hrcC and hrpF of X. campestris pv. vesicatoria were identified. The nonpathogenic mutant 8-13 had a mutation in a gene homologous to hrpF of X. campestris pv. vesicatoria and failed to cause HR on pepper plants but still induced HR on tomato leaves. The nonpathogenic mutant 26-13 had an insertional mutation in a gene homologous to hrcC of X. campestris pv. vesicatoria and lost the ability to induce HR on pepper leaves but still caused HR on tomato plants. Unlike other phytopathogenic bacteria, the parent strain and these two mutants of X. campestris pv. glycines did not cause HR on tobacco plants. a cosmid clone, pBL1, that complemented the phenotypes of 8-13 was isolated. From the analysis of restriction enzyme mapping and deletion analyses of pBL1, a 9.0-kb Eco RI fragment restored the phenotypes of 8-13. pBL1 failed to complement the phenotypes of 26-13, indicating that the hrcC gene resides outside of the insert DNA of pBL1. One nonpathogenic mutant, 13-33, had a mutation in a gene homologous to a miaA gene encoding tRNA delta (2)-isopentenylpyrophosphate transferase of Escherichia coli. This indicated that tRNA modifications in X. campestris pv. glycines may be required for expression of genes necessary for pathogenicity. The mutant 13-33 multiplied as well as the parent strain did in the culture medium and in planta, indicating that loss of pathogenicity is not due to the inability of multiplication in vivo.

• Korean Journal of Materials Research
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• v.33 no.12
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• pp.558-564
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• 2023

In this study, we designed and manufactured a large angular contact ball bearing (LACBB) with low deformation using JIS-SUJ2 steel and analyzed changes in its structural characteristics and chemical composition upon heat treatment. The bearing was produced by hot forging and heat treatment including a quenching and tempering (Q/T) process, and its properties were analyzed using 4 mm thick specimens. A difference in the size distribution of the carbide in the outer and inner parts of the bearing was observed and it was confirmed that large and non-uniform carbide was distributed in the inner part of the bearing. After heat treatment, the hardness value of the outer part increased from 13.4 HRC to 61 HRC and the inner part increased from 8.0 HRC to 59.7 HRC. As a result of X-ray diffraction (XRD) measurements, the volume fraction of the retained austenite contained in the outer part was calculated to be 3.5~4.8 % and the inner part was calculated to be 3.6~5.0 %. The surface chemical composition and the content of chemical bonds were quantified through X-ray photoelectron spectroscopy (XPS), and a decrease in C=C bonds and an increase in Fe-C bonds were confirmed.