• Proceeding of EDISON Challenge
• /
• 2015.03a
• /
• pp.163-166
• /
• 2015

Intramolecular energy migration in a cyclic porphyrin array is spontaneous transfer of energy from one excited site to another. Since the efficiency of energy migration is inversely proportional to distance, the energy migration is occurred on their adjacent sites more often than distant ones. Therefore, the energy migration in the cyclic porphyrin array is largely dependent on their conformational characters. However, evaluation of conformational information by means of experimental tools is ambiguous since their limited resolution. In this work, we calculate the internal angle and distance distributions of cyclic porphyrin arrays using molecular dynamics simulations to obtain conformational information. To evaluate the angle and distance distributions respect to molecular size, we constructed molecules with n porphyrin dimers (n=1,3,7) in implicit solvent environment. Performing molecular dynamics simulations, we modulated alkyl groups to investigate additional conformational effects of the system.

• The Korean Journal of Applied Statistics
• /
• v.29 no.3
• /
• pp.487-503
• /
• 2016

Urban-to-rural migration for farming has recently emerged as a new way to vitalize rural economies in a fast-aging rural Korea. In this paper, we analyze the 2013 data of returning farmers with statistical network methods. We identify urban to rural migration hubs with centrality measures and find migration trends based on regional clusters with similar features via statistical network models. We also fit a latent distance model to investigate the role of distance in migration.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.3 no.1
• /
• pp.13-29
• /
• 2005

This study was performed to examine the effects of therapeutic doses of ultrasound on cell migration distance and proliferation of biopsies from articular cartilage. Articular cartilage biopsies were isolated from proximal part of the tibial of chicken, and cultured. Cartilage explants were exposed for a single 5 min to ultrasound with $0.1{\sim}1.6\;W/cm^2$ (spatial average-temporal average) at a frequency of 1 MHz. A control group was treated with the ultrasound generator switched off. The cell migration distance and cell proliferation analysis were performed on day 6 after stimulation of ultrasound. The results revealed that ultrasound influenced cell migration distance and cell proliferation in intensity-dependent manner. It was found that ultrasounds at $0.2\;W/cm^2$, $0.4\;W/cm^2$, and $0.8\;W/cm^2$ were significantly increase respectively both cell migration distance and cell proliferation (p<0.05). However, cell migration distance and cell proliferation were not affected by exposure ultrasound at $0.1\;W/cm^2$ and $1.6\;W/cm^2$ compared with control group. These results suggest that low-intensity ultrasounds at $0.2\;W/cm^2$, $0.4\;W/cm^2$, and $0.8\;W/cm^2$ may stimulate cell proliferation of the chondroblasts, and reflect a potential role in cartilage repair.

• Archives of Plastic Surgery
• /
• v.32 no.2
• /
• pp.143-148
• /
• 2005

Chemotactic migration of bone forming cell, osteoblast, is an important event during bone formation, bone remodeling, and fracture healing. Migration of cells is mediated by adhesion receptors, such as integrins, that link the cell to extracellular matrix ligands, type I collagen, fibronectin, laminin and depend on interaction between integrin and extracellular ligand. Our study was designed to investigate the effect of extracellular matrix like fibronectin, laminin, type I collagen on migration of osteoblast. Migration distance and speed of MC3T3-E1 cell on extracellular matrix-coated glass were measured for 24 hours using 0.01% type I collagen, 0.01% fibronectin, 100 microliter/ml laminin. The migration distance and speed of MC3T3-E1 cell was compared using a video-microscopy system. To determine migration speed, cells were viewed with a 4 phase- contrast lens and video recorded. Images were captured using a color CCD camera and saved in 8-bit full-color mode. The migration distance on 0.01% type I collagen or 0.01% fibronectin was longer than that on $100{\mu}l/ml$ laminin-coated glass. The migration speed on fibronectin-coated glass was 68 micrometer/hour which was fastest. The migration speed on type I collagen-coated glass was similar with that on fibronectin-coated glass. The latter two migration speeds were faster than that on no-coated glass. On the other hand, the average migration speed on laminin-coated glass was 37micrometer/hour and not different from that of control group. In conclusion, the extracelluar matrix ligands such as type I collagen and fibronectin seem to play an important role in cell migration. The type I collagen or fibronectin coated scaffold is more effective for migration of osteoblast in tissue engineering process.

• Korean Journal of Environment and Ecology
• /
• v.30 no.3
• /
• pp.328-334
• /
• 2016

This study identified the habitat use pattern and migration distance of spot-billed ducks during winter that occur for breed and wintering. The study was carried out using GPS-mobile phone based Telemetry (WT-300) to provide the research results as basic data for protection and management of the habitats of water birds in Korea. The tracking devices (WT-300) were attached to a total of twenty spot-billed ducks collected from the rivers and reservoirs in Gyeonggi-do Anseongcheon, Chungcheongnam-do Seocheongun, Jeollabuk-do Mangyunggang, Dongjingang, and Jeollanam-do Haenamgun. It was found that spot-billed ducks used rivers most frequently as their habitats (47.3%), followed by rice fields, ocean, inland wetlands, and tidal flats. While spot-billed ducks used rice fields at night time and ocean, inland wetlands, and tidal flatss at day time, they used rivers regardless of time. Change rate of habitat use pattern was highest between 6:00am and 8:00am and between 16:00pm and 18:00pm. The average daily migration distance was $0.75{\pm}0.27km$/2hours and accumulated migration distance was 8.95km. Spot-billed ducks covered the longest migration distance between 6:00am and 8:00am and between 16:00pm and 18:00pm; the distance they moved during the periods from 6:00am to 8:00am and from 16:00pm to 18:00pm was 2km but during the rest of the time, it was less than 1km for equivalent durations. The time when spot-billed ducks covered the longest migration distance also corresponds to the time when they showed the greatest change rate of habitat use pattern.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.279-279
• /
• 2012

In order to estimate the average migration lengths of $H_3O^+$ ions in amorphous ice, we conducted experiments of reactive ion scattering (RIS), low energy sputtering (LES), and reflection absorption IR spectroscopy (RAIRS) with an ultra-high vacuum (UHV) chamber. Dopped water-ice films were grown on the clean surface of Ru single crystal and analyzed with RIS, LES and RAIRS methods. The population changes of probe molecules, which were buried at a controlled distance from the surface, were monitored by those methods so that we can mesure the migration efficiencies. From the measured efficiencies, we evaluated the average migration lengths. This result is expected to give the information about the dynamics of proton in water-ice film.

• Journal of the Korean Ceramic Society
• /
• v.32 no.10
• /
• pp.1117-1122
• /
• 1995

The effect of grain boundary structure on zigzag migrtion has been studied. Five kinds of a(2110)-m(1010) diffusion couples with different twist angles by 30$^{\circ}$from a [0001] common direction of each plane were prepared. When chromia (Cr2O3) was added to the diffusion couples by a vapor phase, zigzag migration of the grain boundary occurred. The fraction of zigzag migration did not essentially vary with the twist angle, but the magnitude and migration distance of individual migrating segment varied. The variation of CIGM morphology thus appears to result from the change in grain boundary mobility due to microscopic deviation of grain boundary structure out of a macroscopic grain boundary orientation.

• Journal of the Korean Geographical Society
• /
• v.52 no.1
• /
• pp.105-122
• /
• 2017

The purpose of this study is to understand the urbanization process and identify the Origin-Destination(O-D) of migration in the period of the Japanese occupation, based on the census data about Bu and Jijung-myeon. For this, the study analysed the types and the location of the immigrants' origin(birthplace) whose headed for an urban area. In 1930, as the destinations in the inter-regional migration, the urban areas could be divided into three categories according to the distance: long-, medium- and short-distance. The new urban areas which developed for effective colonial rule by Japanese pulled the long distance immigrant across the Korean Peninsula, and the Chosun Dynasty's traditional cities had the inflow of population from the near and hinterland. All in all, it is proposed that the dual settlement systems of colonial and traditional structures, is the key to understand the Korean urbanization processes basedd on the inter-regional migration during Japanese colonial period.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.5
• /
• pp.1285-1293
• /
• 2014

Several interesting features in trajectory were observed in the direct dynamics study of formaldehyde dissociation above radical dissociation limit. The hydrogen atom deliberately placed on the radical dissociation path can turn around at some distance from C without completion of dissociation and return to HCO moiety, colliding with it just as in a radical-radical recombination and producing a highly energized molecule. Excursion of a hydrogen atom to a distance of 6-8 bohrs and migration of a hydrogen atom back and forth between C and O are two of the most interesting features exhibited by the energized molecule. A series of excursions is seen to lead to a different kind of dissociation resembling roaming-like dissociation characterized by high vibrational excitation of $H_2$ fragment. It is suggested that excursion occurs due to involvement of two different force field systems that exhibit discontinuity in 6-8 bohrs from HCO moiety. We argue that roaming is a non-zero impact parameter version of the excursion.

• Journal of the Korean association of regional geographers
• /
• v.11 no.2
• /
• pp.169-186
• /
• 2005

This paper has focused on the geographical patterns of migrations and the influence of housing value(apartment) per pyung on the migrations within the one city(Seoul) for 1995$\sim$2003. The migration flows which are composed of the origin, the destination and the number of migrants, are examined at the administrative gu and dong level. As most migrations occur among adjacent gus and dongs, short-distance migration is prominent But there is a tendency for the short-distance migrations to occur between specific regions. Since the economic crisis of 1997 out of which Korea was rescued by IMF, differentiation of housing price is so evident that residental relocation is selective among dongs. It seems that the differentiation of housing price has begun to facilitate the relocation of households. Certain social groups are excluded from high-quality residences, as they cannot afford the high price. The number of migrants between dongs is closely related to the variation of the housing value per pyung within dongs. The short-distance migration may reflect this phenomena simultaneously. It seems that the intra-urban migrations in Seoul play a important role to produce and reinforce the residential segregation.