• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1432-1435
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• 1998

Influences of carbon black contents on the tracking resistance, tan $\delta$ and dielectric constant volume resistivity and dielectric strength of EPDM compounds before and after a exposure to UV radiation were investigated. Carbon black content up to 1.5 phr have a positive effect to improve the resistance to tracking and erosion, since carbon black diminish the leakage current. Results from the study reveal that both tan $\delta$ and dielectric constant volume resistivity and dielectric strength are unaffected by adding of carbon black up to 2.0 phr and carbon black have a significant effect to suppress the photo-degradation of EPDM compounds.

• Publications of The Korean Astronomical Society
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• v.25 no.3
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• pp.77-82
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• 2010

Recent results from large surveys of the local universe show that the galaxy-black hole connection is linked to host morphology at a fundamental level and that there are two fundamentally different modes of black hole growth. The fraction of early-type galaxies with actively growing black holes, and therefore the AGN duty cycle, declines significantly with increasing black hole mass. Late-type galaxies exhibit the opposite trend: the fraction of actively growing black holes increases with black hole mass. Issues of AGN selection bias and prospects for near-future efforts with high redshift data are discussed.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.103-110
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• 1990

To investigate the damage on the black pine(Pinus thunbergii) by the air pollution around Ulsan Industrial Complex, forty-six plots were set up and the effects of air pollution were evaluated with the injured index of black pine. The injured index of black pine showing the degree of air pollution from 1987 to 1988 indicated that the central area of Yeochun-dong and Youngjam-dong were heavily damaged. The effective indicaters of black pine damage from air pollution in the order of importance were the color change of one-year-old branch, the ratio of fallen needle of two-year-old branch, the degree of reducing needle, and the degree of growing shoot growth. There was a reliable relationship between the content of $SO_3$ and F in the air and the injured index of black pine. There was no significant correlation between the injured index of the black pine and the content of chemical properties in soil.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.729-731
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• 1998

A black leg disease in wasabi occurred, showed black spots on the leaves, changed a rhizome color to black by invading the vascular bundles of stem and root, thus lowered the quality of the rhizome. The mycelium of the pathogen was yellow at first and then turned to dark yellow on oat meal agar medium. The pycnidium was globose or subglobose, dark brown in color, and 44~120$\times$28~170 ${\mu}{\textrm}{m}$ in size and had one or two ostioles on the upper part. The pycnidiospores are single-celled, hyaline, and 4~6$\times$1.2~2.3 ${\mu}{\textrm}{m}$ in size. The causal pathogen was identified as Phoma wasabiae. The black leg disease of wasabi occurred within the range of 28 to 32% at Chonbuk province in 1994~1995. The disease was appeared from April to October and severe in June and July. The black leg caused by P. wasabiae was first described in Korea.

• Elastomers and Composites
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• v.26 no.4
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• pp.287-295
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• 1991

The mixing process with carbon black is important in the rubber industries. However, it is difficult to characterize the mixing mechanism of the carbon black. The mixing mechanism(distributive mixing and dispersive mixing) was discribed in this paper. The effect of fill factor on the mixing of the carbon black was studied. The dispersive mixing ability increases with increasing fill factor. However, the distributive mixing ability decreases with increasing fill factor. The effect of the carbon black content on the rheological property of the material was studied in this paper. The viscosity of the material increases with increasing the carbon black content. However, the elasticity of the matarial decreases with the carbon black content.

• Child Studies in Asia-Pacific Contexts
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• v.5 no.1
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• pp.51-62
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• 2015

This study examined the role of ethnicity and extended family relationship in the longitudinal patterns of unmarried resident fathers' engagement with young children in the U.S. Using three waves of panel data from the Fragile Families and Child Wellbeing Study (FFCWS), data obtained from 292 respondents were analyzed by the Linear Mixed Effects Regression (LMER) method. Findings suggested that Black unmarried resident fathers exhibited more engagement with their infants at age one than their White counterparts did, but the initial difference reversed by age five as a result of decreasing engagement among Black fathers over time and comparatively increasing engagement among Whites. Results also suggested that Black unmarried resident fathers with a high relationship level with their extended family members exhibited less engagement with their infants than Black fathers with a low relationship level, but the initial difference reversed by age five as a result of decreasing engagement among Black fathers with a low relationship level over time and comparatively increasing engagement among Black fathers with a high relationship level.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.691-696
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• 2013

Black carbon contributes to global warming and melting of polar ice as well as causing respiratory diseases. However, it is also an inexpensive, easily available carbon nano material for elementary chemistry experiments. In this study, black carbon samples collected from candle light and automobile exhaust pipes have been investigated to examine their compositions and surface characteristics. The observed broad G and D bands and amorphous $sp^3$ band in their Raman spectra as well as the high intensity of the D (defect) band reveal that black carbon is principally made of amorphous graphite. The black carbon deposits in automobile exhaust pipes are apparently more amorphous, probably due to the shorter time allowed for formation of the carbonaceous matter. An exceptionally large water contact angle ($159.7^{\circ}$) is observed on black carbon, confirming its superhydrophobicity. The surface roughness evidently plays an important role for the contact angle much larger than that of crystalline graphite ($98.3^{\circ}$). According to the Sassie-Baxter equation, less than 1% the area actually in contact with the water drop.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.47-50
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• 1998

For the quantitiative determination of chemical and taste components in black omija(Schizandra nigra Max) and omija(S.chinensis), compositions of free sugars, free amino acids, total amino acids, and minerals were analyzed. Among the total free sugars in black omija and omija, glucose and frutose were major free sugars and sucrose was little amount. The most abundant free amino acid in black imija was histidine and that in imija was serine. The major free amino acid in black omija and omija were histidine, serine, glutamic acid and aspartic acid. The major total amino acids in black omija and omija were glutamic acid, arginine , leucine and histidine. The limiting amino acid of each omija was S-containing amino acids. The abuntdant minerals in black omija and omija were K and Ca.

• IE interfaces
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• v.11 no.2
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• pp.139-147
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• 1998

The purpose of this study is to survey colors of background, marker, and pointer being used in passenger car's combination meter, and to suggest ergonomic design guidelines of combination meter to enhance driver's readability. An experiment was conducted, in which colors of background, marker, and pointer were selected as independent variables, and reading time, reading error, and preference for combination meter were measured as dependent variables. Most of passenger cars sold in Korea were found to have combination meter with black background, while marker. The experimental results showed that reading time of combination meter with white background, black marker and point was shortest, reading error was lowest in combination meter with black background, yellow marker pointer, and preference for combination meter with white background, black marker and black or red pointer was highest. The results implied that combination meter with white background, black marker and black pointer should be used for comprehensively optimizing reading time, reading error, and preference for it. It was expected that these results could be used as valuable design guidelines when designing combination meter of passenger car.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.193-193
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• 2017

The black heart in potato is a physiological disorder that occurs when potatoes suffer from breathing problems. When storing potatoes at a low temperature around $0^{\circ}C$, there is a high possibility that the respiration rate of potato will rise and black heart will occur. Also, respiration can occur easily and briefly in a state where high temperature and ventilation is insufficient. Recently, as black heart has been occurred continuously and severely in South Korea, here we tried to identify the causes of black heart in potato and to develop the control strategy of this disorder. Firstly, we analyzed the influence on the black heart on the basis of preservation containers (breathable plastic box, burlap bag, paper box, sealed plastic box). After harvesting the potato which is cv. Superior, it preserved for 6 months under conditions of temperature $3.5^{\circ}C{\pm}0.2$ and humidity 85%, after then we surveyed the incidence of emergence rate, rate of weight loss and occurrence rate of black heart. Secondly, in order to investigate the time point of black heart initiation under the oxygen concentration condition of 1% or less, The potatoes were used for this experiment stored for 6 months in a aerated plastic box under conditions of temperature $3.5^{\circ}C{\pm}0.2$ and humidity 85% under sufficient oxygen condition. After stored for 6 month, those were stored at $15^{\circ}C$ and below 1% of oxygen for 25 days, and then the incidence of black heart was surveyed. Thirdly, to investigate the effects of the number of days after harvest on the occurrence of black heart, it was examined the occurrence of black heart stored on 40 days and 100 days after harvesting under sealed condition and vacuum condition. The temperature condition of potato storage was stored was at $4^{\circ}C$ and $25^{\circ}C$ in humidity 85%. As a result of investigating the occurrence of black heart depending on the storage containers, all of the potatoes stored in the sealed plastic box had been occurred black heart. However, black heart of the potatoes in the other treatments did not. Potato preserved under the condition of below 1% of oxygen was found to occur 32% black heart after 25 days of storage. The potatoes corresponding to the required number of days after harvesting were stored for 31 days and the black heart was examined on the occurred. As a result, the potatoes which were 40 days after the harvest did not have black heart under sealed condition and vacuum condition. But potatoes harvested 100 days after harvesting had a black heart incidence of 95.7% under sealed condition at $4^{\circ}C$. The potato placed in the vacuum condition and a sealed state at $25^{\circ}C$ was transformed into anaerobic respiration, the inner tissue of tuber collapsed. Therefore, it is considered that black heart is caused by the breathing trouble in the central part when the oxygen is almost consumed after the aerobic respiration which gradually consumes the oxygen. We conclude that the black heart occurred in the central part where exchange of oxygen and carbon dioxide is the slowest is sensitive to respiration disorder. It is thought that research to investigate black heart generation time according to storage conditions and post-harvest state of potatoes is further necessary.