• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.105-105
• /
• 2011

ZnO is a promising material since it could be applied to many fields such as solar cells, laser diodes, thin films transistors and gas sensors. ZnO has a wide and direct band gap for about 3.37 eV at room temperature and a high exciton binding energy of 60 meV. In particular, ZnO features high sensitivity to toxic and combustible gas such as CO, NOX, so on. The development of gas sensors to monitor the toxic and combustible gases is imperative due to the concerns for enviromental pollution and the safety requirements for the industry. In this study, we investigated the effect of substrate temperature and post-annealing on structural and electrical properties of ZnO thin films. ZnO thin films were deposited by pulsed laser deposition (PLD) at various temperatures at from room temperature to $600^{\circ}C$. After that, post-annealing were performed at $600^{\circ}C$. To inspect the structural properties of the deposited ZnO thin films, X-ray diffraction (XRD) was carried out. For gas sensors, the morphology of the films is dominant factor since it is deeply related with the film surface area. Therefore, the atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM) were used to observe the surface of the ZnO thin films. Furthermore, we analyzed the electrical properties by using a Hall measurement system.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.11a
• /
• pp.343-343
• /
• 2002

This study examines the influence of long-range transport of dust particles and air pollutants on both local/regional DMS oxidation chemistry and the distribution of sulfur compounds at Jeju Island (33.17$^{\circ}$ N. 126.10$^{\circ}$ E) during the Asian dust-storm(ADS) period in April 2001. The atmospheric concentrations of these sulfur species were measured at a ground station on Jeju Island. Korea as Part of the ACE-Asia intensive operation. Three ADS events were observed during the periods of 10-12, 13-14. and 25-26 April. respectively. The concentrations of DMS and CS$_2$ were higher during the ADS period than during the non-Asian-dust-storm (NADS) period. Conversely. a difference in SO$_2$ levels during the ADS period was not distinguishable from those during the NADS period. The diurnal variation pattern of DMS observed was largely different from that in the remote marine boundary layer. DMS loss by NO$_3$ in the atmospheric boundary layer was dominant due to significantly high NOx levels influenced by the long-range transport of pollutants from East Asia to Jeju Island The DMS maximum during the ADS period was observed in the late afternoon. The oceanic fluxes of DMS during the ADS and NADS periods were estimated to be 5.7$\pm$2.3 and 2.9 (+2.8/-1.5) mole m$^{-2}$ day$^{-1}$ . respectively. The contribution of oxidized DMS to SO$_2$ levels at Jeju Island during the study period was found to be insignificant.

• Journal of Wetlands Research
• /
• v.12 no.2
• /
• pp.1-12
• /
• 2010

This study examined geological characteristics of a wetland in Mountain Geumjeong in Busan Metropolitan City. Field survey and laboratory tests were performed to identify topographic features, geological and structural geological characteristics, rock strength along the distance from the wetland, soil profile in the wetland, and chemical property of the wetland soil. The bedrock of the wetland consists of hornblende granite. Hornblende granite and rhyolitic rock around the wetland have the joints with strikes of N-S, E-W, and NE-SW directions and with higher dips greater than $60^{\circ}$. Lower rock strength and higher weathering grades take place towards the wetlands. According to X-ray diffraction analysis of wetland soil samples, kaolinite, montmorillonite, and gibbsite appear which demonstrate weathered products of feldspars in the hornblende granite. The soil profile in the wetland comprises O, A, B, and C horizons from the land surface. The contents of the organic matters decrease from shallow parts to deeper parts of the soil profile. In addition, $K^+$ and $Na^+$ originating from the weathering of feldspars are dominant components among inorganic ions in the wetland soil.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.61 no.6
• /
• pp.31-40
• /
• 2019

In order to implement practical alternatives to proactively cope with the agricultural drought, the potential vulnerability of irrigation pumping stations to agricultural drought was quantitatively evaluated. Data for the 124 pumping stations which are correlatable to the three proxy variables, i.e. exposure, sensitivity, and adaptive capacity was collected by the Korea Rural Community Corporation, and then standardized considering distribution of each data set. Finally, the vulnerability index was calculated by multiplying the weights determined by the expert survey. The results showed that the vulnerability index ranged from 0.709 to 0.331 and the most vulnerable pumping stations such as Judam, Wongoo and Jinahn were mostly located in Gyeongbuk province likely because of the climatological characteristics with high temperature and low rainfall around this area. In addition, it was found that the adaptive capacity was a dominant factor comparing to exposure or sensitivity proxy variables in contributing to the vulnerability. It is therefore recommended that more practical alternatives should be employed to effectively reduce the vulnerability of an individual pumping station to agricultural drought. Furthermore, the corresponding data related to adaptive capacity should be systematically organized and managed at a field level to design reliable adaptation strategies.

• Nuclear Engineering and Technology
• /
• v.47 no.7
• /
• pp.939-944
• /
• 2015

The calibration methods of neutron-measuring devices such as the neutron survey meter have advantages and disadvantages. To compare the calibration factors obtained by the shadow cone method and semi-empirical method, 10 neutron survey meters of five different types were used in this study. This experiment was performed at the Korea Atomic Energy Research Institute (KAERI; Daejeon, South Korea), and the calibration neutron fields were constructed using a $^{252}Californium$ ($^{252}Cf$) neutron source, which was positioned in the center of the neutron irradiation room. The neutron spectra of the calibration neutron fields were measured by a europium-activated lithium iodide scintillator in combination with KAERI's Bonner sphere system. When the shadow cone method was used, 10 single moderator-based survey meters exhibited a smaller calibration factor by as much as 3.1-9.3% than that of the semi-empirical method. This finding indicates that neutron survey meters underestimated the scattered neutrons and attenuated neutrons (i.e., the total scatter corrections). This underestimation of the calibration factor was attributed to the fact that single moderator-based survey meters have an under-ambient dose equivalent response in the thermal or thermal-dominant neutron field. As a result, when the shadow cone method is used for a single moderator-based survey meter, an additional correction and the International Organization for Standardization standard 8529-2 for room-scattered neutrons should be considered.

• Korean Journal of Environmental Agriculture
• /
• v.34 no.2
• /
• pp.77-90
• /
• 2015

BACKGROUND: The field margins, which are uncultivated area of permanent vegetation located adjacent to field, play an important role in enhancing biodiversity in the agricultural ecosystem. This study focused on floristic characteristics on dry field margins in Korea Peninsula. METHODS AND RESULTS: This study was conducted at margins of 196 dry fields in 32 areas in 8 provinces in May and September 2013. The vascular plants of the dry field margins were listed 347 taxa which contain 73 families, 219 genera, 311 species, 1 subspecies, 30 varieties and 5 forms. Of these 347 taxa, 48 taxa were woody plants and 299 taxa were herbaceous plants. Among total 73 families, Compositae (17.6%) was the most dominant family, and followed Gramineae (15.9%), Polygonaceae (5.8%), Leguminosae (4.9%) and Cyperaceae (3.8%). Based on relative frequency values of survey fields, the appearance frequency of Digitaria ciliaris (89.8%) was the highest, and followed Acalypha australis (86.2%), Artemisia princeps (82.1%), Commelina communis (80.6%) and Portulaca oleracea (80.6%). Disturbance index of dry field margins was 55.0% at national level, and Gangwon region was the highest among the 8 regions at regional level. Life form spectrum was determined to be $Th-R_5-D_4-etype$. CONCLUSION: These results will be used fundamental data for studies to improve or even stabilize the current state of plant biodiversity in agricultural environments.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.15
• /
• pp.1-31
• /
• 1974

Introducing genes for earliness of wheat varieties is important to develop early varieties in winter wheat. In oder to obtain basic informations on the response of heading to the different day length and temperature treatments and on the inheritance of heading dates, experiments were conducted at the field and greenhouse of the Crop Experiment Station, Suwon. Varieties used in this experiments were, early variety Yecora F70, medium varieties Suke #169, Parker and Yukseung #3, and late varieties Changkwang, Bezostaia, Sturdy and Blueboy. The parents and F$_1$s of partial diallel crosses of above eight varieties were subjected the following four different treatments; 1. high temperature and long day, 2. high temperature and short day, 3. low temperature and long day, and 4. low temperature and short day. The same materials were grown also in field condition. Parents, F$_1$ and F$_2$ generation were grown also in both greenhouse under high temperature and short day and in field. The results obtained were summarized as follow: 1. No effects of temperature and daylength on the number of leaves on the main stem were found when -varieties were vernalized. The number of main stem leaves were fewer for spring type of varieties than for winter type of varieties. 2. The effects of temperature and daylength on the days to flag leaf opening were dependent on the speed of leaf emergence. The speed of leaf emergence were faster for lower leaves than for upper leaves. 3. The response to short day and long day (earliness of narrow sense) of varieties were found to be direct factor responsible to physiology of heading dates in vernalized varieties. Great difference of varieties to heading date was found in high temperature and short day treatment, but less differences were found in high temperature and long day, low temperature and long day and low temperature and short day treatments respectively. The least varietal difference for heading dates was found in the field condition. 4. Changkwang and Parker were found to be the most sensitive to short day treatment (photosensitive) and the heading of these varieties were delayed by short day treatment. No great varietal differences were found among other varieties. 5. Varietal differences of heading dates due to daylength were greater in high temperature than in low temperature. 6. Varietal differences of heading dates due to temperature were not great. but in general the heading dates of varieties were faster under high temperature than under low temperature. 7. Earliness of heading dates was due to partial dominance effect of genes involved in any condition. The degree of dominance was greater under short day than under long day treatment. 8. The varietal differences of heading date under high temperature and long day were due to earliness or narrow sense (response to long day) of varieties. The degree of dominance was greater for Yecora F70, spring type than for other winter type of varieties. No differences or less differences of degree of dominance was found among winter type of varieties. The estimated number of effective factor concerned in the earliness of narrow sense was one pair of allele with minor genes. 9. The insensitivity of varieties to short day treatment in heading dates was due to single dominant gene effect. Under the low temperature the sensitivity of varieties to short day treatment was less apparent. 10. The earliness of short day and long day (earliness of narrow sense) sensitivities of varieties appearea to be due to partial dominance of earliness over lateness. In strict sense, the degree of the dominance should be distinguished. 11. Dominant gene effects were found for the thermo-sensitivity of varieties, and the effect was less, significant than the earliness in narrow sense. 12. One pair of allele, ee and EE, for photosensitivity was responsible for the difference in the heading dates between Changkwang and Suke #169. Two pairs of alleles, ee, enen and EE, EnEn. appeared to be responsible for the difference between Changkwang and Yecora F70. The effects of EE and EnEn were, additive to the earliness and the effects of EE were greater than EnEn under short day. However, the effects of EE were not evident in long day but the effects of EnEn were observed in long day. 13. Two pairs of dominant alleles for the earliness were estimated from the analysis of F$_1$ diallels in the field but the effects of these alleles in F$_2$ were not apparent due to low temperature and short day treatment in early part of growth and high temperature and long day treatment in later part of growth. The F$_2$ population shows continuous variation due to environmental effects and due to other minor gene effects. 14. The heritabilities for heading dates were ranged from 0.51 to 0.72, indicating that the selection in early generation might be effective. The extent of heritability for heading dates varied with environments; higher magnitude of heritability was obtained in short day treatment and high temperature compared with long day and low temperature treatments. The heritabilities of heading date due to response to short day were 0.86 in high temperature and 0.76 in low temperature. The heritabilities of heading date due to temperature were not significantly high. 15. The correlation coefficients of heading dates to the number of grains per spike, weight of 1, 000 grains. and grain yield were positive and high, indicating the difficulties of selections of high yielding lines from early population. But no significant correlation coefficient was obtained between the earliness and the number of spikes, indicating the effective selection for high tillering from early varieties for high yielding.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.10
• /
• pp.758-765
• /
• 2002

KITECH and ODS performed a study of internal and external noise prediction of the Korean high speed prototype test train(HSR 350X). The object of this study was 3 kinds of cars, trailer car(TT2), motorized car(TMI ) and power car(TPI) and the predicted noise was for the two different driving speeds in free field and tunnel conditions. Data of carbody design and noise sources were delivered from manufactures. Some of noise sources which were not available in the project team, were chosen by experiences of ODS. Internal noise level of each car was predicted for two cases i.e, at 300 km/h and 350 km/h. In addition sound transmission path and dominant noise sources were also investigated for each section of the car, which is circular shell typed part of whole carbody. In case of TT2, the dominating sound transmission path is the (floor in terms of structure-borne noise and air-borne noise. The main noise sources are structure-borne noise from the yaw-damper and air-borne noise from the wheel/rail contact, whereas the dominating sound transmission path of TMI are floor and sidewall below the window in terms of structure-borne noise. The main noise sources of TMI are structure-borne noise from motor/gear unit and the yaw-damper in the free field, and air-borne noise from the wheel/rail contact and structure-borne noise from motor/gear unit in the tunnel. Through the external noise prediction for the KHST test train formation, the noise form the wheel/rail contact is estimated as one of the major sources. In addition, the noise specification of sub-component was proposed for managing each sub-surpplier to reach the KHST noise requirement. The specification provide the sound power of machinery part and transmission loss of component of carbody structure. The predicted noise level in each case exceeded the required limit. Through this study, the noise characteristics of the test train were investigated by simulation, and then the actual test will be performed in near future. Both measured and calculated data will be compared and further work for noise reduction will be continued.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.4
• /
• pp.292-297
• /
• 2007

Global warming and climate changes have been major issues for decades andvarious researches have reported their impact on our environment. According to recent researches, increased carbon dioxide ($CO_2$) concentration in the atmosphere is considered as a dominant contributor to global climate changes and thus numerous researches were conducted to control $CO_2$ concentration in the atmosphere. Soil management practices, such as reducing tillage intensity, returning plant residues, and enhancing cropping system have recommended for restoring organic carbon into the soils effectively. However, few studies on soil carbon sequestration have reported for Korean paddy soils. Therefore, evaluation of soil organic carbon (SOC) dynamics in the long-term single rice cropping system is essential in order to find out potential capacity of paddy field as a carbon sink source. The objective of this research was to evaluate SOC dynamics on the long-term single rice cropping system. Research was conducted in the research farm at National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon. Long-term phosphorus and potassium fertilization and lime application didn't significantly affect on SOC compared to controls. We found that SOC contents were increased continually at the long-term composting plots with enhanced rate of carbon storage. In conclusion, continuous incorporation of plant residues (i.e., composting) is recommended to effectively sequester soil carbon for Korean paddy soils. This result implies that continuous composting in a paddy field may contributenot only for increasing SOC in the soils but also for mitigating global warming through reducing carbon dioxide emission into atmosphere. Therefore, we recommend that a strategy or policy measures to encourage farmers to return plant residues continuously for mitigation of global warming as well as soil fertility is being developed.

• Journal of Science and Technology Studies
• /
• v.14 no.1
• /
• pp.3-33
• /
• 2014

Over the last forty years, the dominant perspective of social science on medicine has been the medicalization theory. It indicates the social process of expanding power of medical professionals by (re)defining the problems which were treated as non-medical phenomena(e.g. homosexuality, alcoholism, obesity, etc.) into "diseases" and thus the spheres of medical intervention. Meanwhile, rapid technoscientific changes in the medical field owing to the diffusion of biological sciences and information technologies since the mid-1980s and the accompanying emergence of new social arrangements such as bioeconomy and biological citizenship have led to the rise of a new social scientific perspective called the biomedicalization theory. This paper attempts to compare the two theories and assess their merits and demerits as a basic work to deepen the understandings of sociology and STS on contemporary medicine. And it also attempts to analyze their relative relevance through the case of mental disorder. The analysis on the case of mental disorder clearly shows that the medicalization in that area seems to have continuously proceeded since the early 19th centiry to the present. Furthermore, it also seems true that the five central processes of biomedicalization(except for risk surveillance technologies of mental disorder) have been observed and realized since the late 20th century. These results indicate that although medicalization has consistently proceeded, it has not been limited to the quantitative expansion of the medical field but been extended to the qualitative transformation asserted by the biomedicalization theory. Therefore, while the concept of medicalization is valid and significant even today, we can recognize that the concept of biomedicalization allow us to capture the new phenomena which cannot be properly and sufficiently captured by that of medicalization.