• Journal of Sericultural and Entomological Science
• /
• v.54 no.1_2
• /
• pp.17-22
• /
• 2016

Rearing environment direct effects on oviposition preference of black soldier fly(Hermetia illucens). In this study, the number of egg-filled flutes was surveyed according to the size of adult rearing cages and oviposition media of black soldier fly (BSF). The height of the adult rearing cages were fixed at 2 m and provided different sizes of width and length and released 20,000 BSF adults in the rearing cages. The mean number of BSF egg-filled flutes was 895.4 at $4{\times}4m$ cage, 876.3 at $2{\times}1m$ cage and 62.3 at $1{\times}1m$ cage. Comparison of egg-filled flutes was according to cages material of adult BSF. The mean number of egg-filled flutes were 820.7 and 604.3 at different cage materials such as mosquito net and green house film. The mean numbers of egg-filled flutes were 326.6 in green floral form, 135.2 in green corrugated cardboard and 41.0 in brown corrugated cardboard. And the mean number of egg-filled flutes were similar floral form with the corrugated cardboard was overlapped by floral form such as 57.7 and 64.7. The mean number of egg-filled flutes was 29.0 and 48.2 in 6 mm and 4 mm diameter of oviposition hole.

• Journal of the Korean Professional Engineers Association
• /
• v.5 no.19
• /
• pp.3-16
• /
• 1972

1. Purposes and importances of the study. In gaining heating resources by combustion of briquette, which is the necessaries of every day's life, victims occur from poisonous affection of combustion gas (carbon mono-oxide) in every year and this gas attributable to increase death rate proportion to the high demand of briquette usage. It arise great problem ill point of national sanitation. Therefore, the study has a big aim to accomplish depressing CO gas or stimulating comlete combustion by both the methods of physical improvement of present combustion devices and chemical improvement by using V$_2$O$\sub$5/ catalyst to depress CO gas or fasten complete combustion Progress. Sucessful result of this study will not only to decrease the death rate but also to contribute fearless handling of briquette combustion so as to perform improving public Welfare. 2. Contents and scope of study. A. comparison of present and improved fuel hole device. B. Examination of effectness of improved elements. C. Effectness of miffed usage of catalyst. D. Comparison of Catalyst effectness. E. Examination of effectness of black slate containing V$_2$O$\sub$5/. 3. Results and recommendations of the study A. Absolute necessity of supplying secondary air by improved combustion device. B. Oxide Vanadium (V$_2$O$\sub$5/) has the greatest effectness to eliminate CO gas. C. Most effective catalyst of V$_2$O$\sub$5/ containing slate comes from "Samgoe" coal mine. D. By plastering catalyst on the cover plate of fire hole, it stimulate chemical reaction of re-combustion and preserving heat. E. Recommend to continute further precise study to practice with low-cost and handy devices to be applied the study results.

• Journal of The Korean Astronomical Society
• /
• v.53 no.5
• /
• pp.103-115
• /
• 2020

We analyze the spatially resolved kinematics of gas and stars for a sample of ten hidden type 1 AGNs in order to investigate the nature of their central sources and the scaling relation with host galaxy stellar velocity dispersion. We select our sample from a large number of hidden type 1 AGNs, which are identified based on the presence of a broad (full width at half maximum ≳1000 km s^-1) component in the Hα line profile and which are frequently mis-classified as type 2 AGNs because AGN continuum and broad emission lines are weak or obscured in the optical spectral range. We used the Blue Channel Spectrograph at the 6.5-m Multiple Mirror Telescope to obtain long-slit data with a spatial scale of 0.3 arcsec pixel^-1. We detected broad Hβ lines for only two targets; however, the presence of strong broad Hα lines indicates that the AGNs we selected are all low-luminosity type 1 AGNs. We measured the velocity, velocity dispersion, and flux of stellar continuum and gas emission lines (i.e., Hβ and [O III]) as a function of distance from the center. The spatially resolved gas kinematics traced by Hβ or [O III] are generally similar to the stellar kinematics except for the inner center, where signatures of gas outflows are detected. We compare the luminosity-weighted effective stellar velocity dispersions with the black hole masses and find that our hidden type 1 AGNs, which have relatively low back hole masses, follow the same scaling relation as reverberation-mapped type 1 AGN and more massive inactive galaxies.

• Safety and Health at Work
• /
• v.8 no.2
• /
• pp.151-155
• /
• 2017

Background: At the entrance of a tunnel, reflection of sunlight from the surrounding environment and a lack of adequate lighting usually cause some vision problems. The purpose of this study was to perform a safety evaluation of lighting on a very long road in Ilam, Iran. Methods: The average luminance was measured using a luminance meter (model S3; Hagner, Solna, Sweden). A camera (model 108, 35-mm single-lens reflex; Yashica, Nagano, Japan) was used to take photographs of the safe stopping distance from the tunnel entrance. Equivalent luminance was determined according to the Holliday polar diagram. Results: Considering the average luminance at the tunnel entrance ($116.7cd/m^2$) and using Adrian's equation, the safe level of lighting at the entrance of the tunnel was determined to be 0.7. Conclusion: A comparison between the results of the safe levels of lighting at the entrance of the tunnel and the De Boer scale showed that the phenomenon of black holes is created at the tunnel entrance. This may lead to a misadaptation of the drivers' eyes to the change in luminance level at the entrance of the tunnel, thereby increasing the risk of road accidents in this zone.

• Publications of The Korean Astronomical Society
• /
• v.26 no.2
• /
• pp.71-87
• /
• 2011

Gravitational waves are predicted by the Einstein's theory of General Relativity. The direct detection of gravitational waves is one of the most challenging tasks in modern science and engineering due to the 'weak' nature of gravity. Recent development of the laser interferometer technology, however, makes it possible to build a detector on Earth that is sensitive up to 100-1000 Mpc for strong sources. It implies an expected detection rate of neutron star mergers, which are one of the most important targets for ground-based detectors, ranges between a few to a few hundred per year. Therefore, we expect that the gravitational-wave observation will be routine within several years. Strongest gravitational-wave sources include tight binaries composed of compact objects, supernova explosions, gamma-ray bursts, mergers of supermassive black holes, etc. Together with the electromagnetic waves, the gravitational wave observation will allow us to explore the most exotic nature of astrophysical objects as well as the very early evolution of the universe. This review provides a comprehensive overview of the theory of gravitational waves, principles of detections, gravitational-wave detectors, astrophysical sources of gravitational waves, and future prospects.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.84.1-84.1
• /
• 2012

One of the most intriguing questions regarding black hole (BH)-galaxy co-evolution picture is how the BH accretion, or active galactic nucleus (AGN) activity is linked to star formation (SF) activity. While it is suggested that AGN luminosity of quasars correlates with SF luminosity, it is still unclear how AGN activity is connected to SF activity based on host galaxy properties. Utilizing AKARI's unique slit-less spectroscopic capability and wavelength coverage, we probed star formation activity of several types of AGNs by measuring the PAH 3.3 ${\mu}m$ emission. First, we detected the PAH 3.3 ${\mu}m$ emission from seven out of 27 Seyfert type-1 galaxies at z~0.36. While these galaxies deviate significantly from the local Mbh-${\sigma}$ relation meaning their black holes proceed the host galaxies in terms of evolution, they appear to follow the correlation between nuclear SF and AGN activities of local Seyfert type-1 galaxies. This implies that SF and AGN activities are directly connected at the nuclear region for these Seyfert type-1 AGNs. We also obtained 2-5 ${\mu}m$ spectra for subsamples of Quasar Spectroscopic Observation in Near-infrared Grism (QSONG) which consists of reverberation-mapped AGNs and PG-QSOs. We detected the PAH 3.3 ${\mu}m$ emission from 16 out of 31 reverberation-mapped AGNs and 10 out of 49 PG-QSOs and measured their line strengths. We present the correlations between SF and AGN activities and discuss if there is any dependency of the correlations on properties of host galaxies, such as morphology, or the presence of radio jets.

• Journal of Astronomy and Space Sciences
• /
• v.18 no.1
• /
• pp.1-6
• /
• 2001

In this paper we investigate the properties of advection-dominated accretion flows (ADAFs) in case that outflows carry away infalling matter with its angular momentum and energy. Positive Bernoulli number in ADAFs allow a fraction of the gas to be expelled in a form of outflows. The ADAFs are also unstable to convection. We present self-similar solutions for advection-dominated accretion flows in the presence of outflows from the accretion flows(ADIOS). The axisymmetric flow is treated in variables integrated over polar sections and the effects of outflows on the accretion flow are parameterized for possible configurations compatible with the one dimensional self-similar ADAF solution. We explicitly derive self-similar solutions of ADAFs in the presence of outflows and show that the strong outflows in the accretion flows result in a flatter density profile, which is similar to that of the convection-dominated accretion flows(CDAFs) in which convection transports the angular momentum inward and the energy outward. There two different versions of the ADAF model should show similar behaviors in X-ray spectrum to some extent. Even though the two models may show similar behaviors, they should be distinguishable due to different physical properties. We suggest that for a central object of which mass is known these two different accretion flow should have different X-ray flux value due to deficient matter in the wind model.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.72.4-73
• /
• 2015

Over the last decade, more than 50 quasars have been discovered at redshift about 6 when reionization of the universe occurred. However, most of them are luminous quasars (zAB < 21 mag), implying that such a biased quasar sample, which cannot represent the entire population of quasars at z~6, is not enough to understand the properties of quasars in the early universe. Recently, we have been performing the Infrared Medium-deep Survey (IMS), a moderately wide (120 deg2) and deep (JAB ~ 22.5 - 23 mag) near-infrared imaging survey. Combining this with the optical (ugriz) imaging data from the CFHT Legacy Survey (CFHTLS), we have identified more than 10 faint quasar candidates at z~6 in the IMS field by using multiple color selection criteria. From now on, we will perform spectroscopic confirmations of these faint quasar candidates with IMACS on the Magellan Baade Telescope at Las Campanas Observatory and GMOS on the Gemini South Telescope at Gemini Observatory. The confirmed quasars will be used to constrain the faint-end slope of the quasar luminosity function at z~6 and calculate the ratio of quasar ionizing flux to required flux for reionization of the universe. Moreover, these confirmed quasars will be followed up with near-infrared spectroscopy to determine their black hole masses and Eddington ratios to check the rapidness of their growth.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.42.2-42.2
• /
• 2015

High frequency peakers (HFPs) are promising candidates for young active galactic nuclei (AGNs). Their small physical scale (< 1 kpc) and radio spectrum peaked at high frequency (> 5 GHz) are suggestive that it has been only about $10^2-10^3$ years since a central massive black hole in their host galaxies was launched. Until recently however, long-term monitoring radio observations at frequencies which are high enough to cover the true peak of HFP candidates were rare. Therefore, previous HFP samples are often contaminated by blazars, which are highly variable, hence may show a similar radio spectrum as HFPs depending on the observational epoch. In this work, we challenge to identify genuine young AGNs by monitoring HFP candidates at high radio frequencies. We performed single-dish monitoring of 19 candidates in 18 epochs over 2.5 years at 22 and 43 GHz using the Korean VLBI Network (KVN). Also, using KaVA, a combined array of the KVN and the VERA in Japan, we carried out 22 GHz VLBI observations of two HFPs and one blazar selected from our sample in order to compare their parsec scale (milli-arcsecond scale) morphology. HFPs are expected to have double/triple features, so called compact symmetric objects, which are scaled-down versions of extended radio galaxies, while blazars typically show core-jet morphology. We discuss the properties of AGNs at their very early evolutionary stage based on the results of the KVN and KaVA observations.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.48.1-48.1
• /
• 2015

We investigate the role of small-scale and large-scale environments in triggering nuclear activity of the local galaxies using a volume-limited sample with $M_r$ < -19.5 and 0.02 < z < 0.0685 from the Sloan Digital Sky Survey Data Release 7. To fix the mass of the supermassive black hole in its host galaxy, we limit the central velocity dispersion of the sample galaxies. The active galactic nuclei (AGN) host sample is composed of Type II AGNs identified with flux ratios of narrow emission lines with S/N > 6. In this study, we find that the AGN fraction of late-type host galaxies are commonly larger than of early type galaxies. The AGN fraction of host galaxy with late-type nearest neighbor starts to increase as the host galaxy approaches the virial radius of the nearest neighbor (about a few hundred kpc scale). Our result may support the idea that the hydrodynamic interaction with the nearest neighbor plays an important role in triggering the nuclear activity of galaxy. The early-type galaxies in high density regions show decline of AGN activity compared to ones in lower density regions, whereas the direction of the environmental dependence of AGN activity for late-type galaxies is rather opposite. We also find that the environmental dependence of star formation rate is analogous to one of AGN activity except in the high density region.