Chul-Un Chung

General Patterns in Echolocation Call of Greater Horseshoe Bat Rhinolophus ferrumequinum, Japanese Pipistrelle Bat Pipistrellus abramus and Large-Footed Bat Myotis macrodactylus in Korea

In this study, we analyzed the pulse-duration, pulse-interval and peak-frequency of echolocation call in three species as Rhinolophus ferrumequinum, Pipistrellus abramus, and Myotis macrodactylus. The peak frequency and pulse duration for above mentioned species were 69 kHz, 47 kHz and 49 kHz and , and for R. ferrumequinum, P. abramus and M. macrodactylus, respectively. The pulse intervals for R. ferrumequinum, P. abramus and M. macrodactylus were , and , respectively. The pulse pattern of R. ferrumequinum was setting into a short FM call and linked to long CF call and went through the short FM call again. The pulse pattern of M. macrodactylus was comprised with serial short FM call and the CF call was not checked up in accordance with the spectrogram analysis. The long FM call and short CF call got join together for the P. abramus and the peak frequency was checked up at the pulse ending as CF call.

Enhancement of TiC/stainless steel interfaces by N+-implantation

Abstract TiC films were deposited on stainless-steel substrates by the reactive radio-frequency magnetron sputtering technique, and N + implantation were performed to enhance the quality of the TiC/stainless steel interface. The deposition rate of the TiC film increased linearly with increasing applied radio-frequency power, and it decreased with increasing partial-pressure ratio of the sputtering gas to the reactive gas. The stoichiometry of the TiC films and the interfacial depth profiles of the TiC/stainless steel heterostructures were investigated by Auger electron spectroscopy measurements. Removal of the oxygen at the TiC/stainless steel interface due to N + -implantation and annealing were observed. These results indicate that the N + -implanted TiC thin films grown on stainless-steel substrates can be used for advanced engineering ceramic applications.

Deep levels in Si-doped AlxGa1-xAs layers

Abstract Deep-level transient spectroscopy (DLTS), multi-exponential DLTS and optical DLTS measurements were performed to investigate the deep levels in Si-doped Al x Ga 1 − x As layers grown by molecular beam epitaxy. The results of the DLTS and the multi exponential DLTS measurements showed two DX centers and those of the optical DLTS measurements showed two OX centers. The DX centers originate from the emission of the carriers toward the conduction band and the OX centers are related to the capture of the carriers from the conduction band by the DX centers. These results are in good agreement with the theory in which the levels of the DX centers in Si-doped Al x Ga 1 − x As layers have a capture and emission barrier due to the Si-doping.

The complete mitochondrial genome of long-tailed whiskered bat, Myotis frater (Myotis, Vespertilionidae)

Abstract Here, we report the complete mitogenome of Myotis frater with the GenBank accession number MH177276 as a first step to elucidate genetic characteristics of this species. Its mitogenome was 17,089 bp long and consisted of 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes, and a control region. The gene order and composition of M. frater was similar to that of most other vertebrates. The base composition of the 13 PCG in descending order was A (33.8%), C (22.7%), T (30.4%), and G (13.1%), with an AT content of 64.2%. Four overlapping regions in ATP8/ATP6, ATP6/COX3, ND4L/ND4, and ND5/ND6, among the 13 PCGs were found. The 935 bp long control region is located between tRNA-Pro and tRNA-Phe with 4 ATTACATAATACATTATATGTATAATCGTACATTAAATTAACTCCCACATGAATATTAAGCATGTCCATACTAATATTAAT-repeat at 5′ region and 45 ACGCAT-repeat at 3′ terminus. Phylogenetic analysis suggested that M. frater is most closely related to M. bechsteinii (KX757757), it was supported by 100% bootstrap under both ML and NJ tree.

Structural Characteristics of Red Fox (Vulpes vulpes) Dens in the Wild in Northeast China and in a Captive Facility in South Korea

The red fox (Vulpes vulpes) has a worldwide distribution (Lariviere and Pasitschniak-Arts 1996), which includes most of North America, Europe, Asia, and northern Africa (Yu et al. 2012). In the past, red foxes were distributed extensively in Korea, and were considered friendly animals in history and culture (National Park Research Institute 2010). However, since the 1980s, it has been speculated that red foxes may have been driven to extinction due to activities such as the protection of livestock, illegal hunting, rodenticide use, and habitat loss (Won and Smith 1999; Yu et al. 2012).Consequently, the species has been placed on the list of endangered species I (Ministry of the Environment of Korea 2005). After 24 years of believing the red fox was endangered, a red fox carcass was found in Yang-gu Gangwondo, Korea, in 2004. Thus, it was suggested that the red fox might still exist in the wild. Although no other wild red foxes have been seen since, a red fox restoration project was initiated in 2009 through basic investigative research. Many carnivores are currently extinct in Korea, and large carnivores in particular have not been found in the wild for many years (National Institute of Biological Resources 2012). Therefore, the red fox restoration program is very important for the healthy recovery of the forest ecological food chain and the restoration of other carnivorous mammals facing extinction. The Ministry of the Environment has performed genetic analyses on a stuffed domestic museum specimen and samples from northeast Asia in an effort to introduce the same variant of red fox as that identified in Korea. The results of these genetic analyses showed that the Korean red fox was part of the same group of red foxes inhabiting North Korea, northeast China, Russia, and Mongolia (Yu et al. 2012). Therefore, 10 red foxes raised under the red fox restoration project were introduced to Korea from northeast China in 2012. The first step of the red fox restoration project in Korea was to continually monitor the foxes after release in the wild. The red fox uses its den year-round (Lindstrom 1994; Carter and Finn 1999; Tryjanowski et al. 2002; Dell’Arte and Leonardi 2007) for shelter, protection from predators, and to raise its cubs (Macdonald and Reynolds 2004). Thus, an understanding of fox den characteristics is needed for managing and monitoring the released foxes. Fox den characteristics are different depending on the habitat type and environment, as well as the species (Tannerfeldt et al. 2003). Although there are many studies on fox dens (Russell and Scotter 1984; Cotterill 1997; Jackson and Choate 2000; McGee et al. 2006), few studies have focused on the characteristics of red fox dens (Nakazono and Ono 1987; Meia and Weber 1992). Research on red fox dens in northeast Asia is particularly rare, except for the studies by Nakazono and Ono (1987) and Uraguchi and Takahashi (1998), while in Korea, no study has examined red fox dens in natural or captive conditions. Although the red fox is endangered in Korea, making it difficult to study wild red fox den characteristics in this region, we have collected various ecological and structural data on the characteristics of fox dens in large captive facilities in Korea. However, fox den characteristics can vary depending on food availability and the environment (Tannerfeldt et al. 2003). In the artificial facilities in Korea, environmental factors such as soil quality, river system accessibility, and vegetation may be different from the features in a future release area. Therefore, we assume that the structural characteristics of dens used in captivity are different from those used in the wild after release. Thus, the purpose of this study was to understand the structural characteristics of fox dens and to use this information for post-release monitoring. Therefore, to study not only the characteristics and structure of red fox dens in captivity, but also in the wild, we visited northeast China and searched for the dens of wild red foxes, which were identified as belonging to the same genetic group as the foxes managed in Korea.

Characteristics of Echolocation Calls of the Parti-coloured Bat, Vespertilio sinensis, in Relation to Environment Type

In this study, we analyzed two types of echolocation calls used by the parti-coloured bat, Vespertilio sinensis. Bats were captured in the Naejangsan National Park in October 2013. Call sounds of hand-released bats were recorded at the location of capture within the National Park. We analyzed pulse duration (PD), pulse interval (PI), peak frequency (PF), maximum frequency (FMAX), minimum frequency (FMIN), and bandwidth (BW). V. sinensis emitted the different types of the echolocation calls depending on the surrounding environment. Frequency modulated-constant frequency (FM-CF) signal of audible range was emitted when they flew in the uncluttered space over the canopy. However, when flying in the cluttered space below the canopy, they only emitted FM signal. FM-CF signal is in the audible range (e.g., low frequency), and FM signal has a harmonic broadband frequency range of two. There were significant differences in PD, PI, PF, FMAX, FMIN, and BW between the calls emitted over and below the canopy. Considering the functional characteristics of FM and CF signals, we conclude that the foraging activity of V. sinensis was observed below the canopy, and recommend the use of FM signal and broadband as echolocation signals.

External Morphology and Environment of Foraging Site in Asian parti-coloured Bat Vespertilio sinensis in Naejangsan National Park

Abstract We have analyzed the external morphology and the environment of the foraging site of Vespertilio sinensis . The external morphology was analyzed by twelve parameters and the environment characteristics of the foraging site was analyzed using GIS 10.1 program. The wing membrane was inserted into the ankle of the hind foot and the wing ratio was 1.42, the middle type between broad-short wing type and long-narrow wing type. The fur color was blackish brown but the guard hair color was whitish. The shape of the ear was a rounded triangle and tragus was a fan shape. This study showed that V. sinensis preferred the deciduous forest of the upper forest zone, where human interference was less. We believed that abundance of insects, depending on water system, was closely related to the use of the foraging site. This result showed that the environment characteristics was very similar to the nature preservation zone including Baekyang valley and Keumsun valley in Naejangsan National Park.

Homing of the Serotine Bat, Eptesicus serotinus (Chiroptera: Vespertilionidae)

Between May and September 2014, a total of 226 serotine bats (Eptesicus serotinus) were captured and subsequently released at a site 50 km distant from the site of capture, in order to determine the homing ability of the bats and changes in the homing rate according to the season. The bats were captured from a nursery colony at a bridge in An-dong (Gyeongbuk, Korea), and then released at a similar site in Yeong-Ju (Gyeongbuk, Korea). We found that 115 of the 226 bats released (51%) returned to the capture site. However, there was a difference in the homing ability of the serotine bats depending on the season and reproductive status. We found that the homing rate was the highest in June during late pregnancy and the lowest in August after the lactation period.

Electrical transport studies in disordered GaAs/AlAs superlattices

Abstract The current-voltage (I–V) characteristics of disordered GaAs/AlAs superlattices were measured to investigate the electron transport phenomena of the intermixing of the superlattices due to thermal treatment. The results of the I– V measurements for the GaAs/AlAs superlattices show different behavior according to the barrier thickness. The measured results show behavior similar to the theoretical calculations.