• 반도체디스플레이기술학회지
• /
• 제13권4호
• /
• pp.1-5
• /
• 2014

The plasma density distribution in between the electrode and lateral wall of a narrow gap CCP was investigated. The plasma density distribution was obtained using single Langmuir probe, having two peaks of density distribution at the center of electrode and at the peripheral area of electrodes. The plasma density distribution was compared with the RF fluctuation of plasma potential taken from capacitive probe. Ionization reactions obtained from numerical analysis using CFD-$ACE^+$ fluid model based code. The peaks in two region for plasma density and voltage fluctuation have similar spatial distribution according to input power. It was found that plasma density distribution between the electrode and the lateral wall is closely related with the local ionization.

• Nuclear Engineering and Technology
• /
• 제54권10호
• /
• pp.3962-3973
• /
• 2022

Several critical heat flux (CHF) correlations including the look-up table in the MARS code have been assessed for the prediction of CHF in a downward-flow narrow rectangular channel. For the assessment, we built an experiment database that covers pressures between 1.01 and 39.0 bar, gap sizes between 1.09 and 6.53 mm, mass fluxes up to 25,772 kg/m²s, and under one-sided and two-sided heating conditions. The results of the assessment showed that the Kaminaga correlation has the best overall prediction compared to others. However, because the correlation uses global variables, such as inlet and outlet subcooling and total heat transfer area, it is difficult to use in a system code. A new CHF correlation is then proposed by replacing the global variables in the Kaminaga correlation with local ones and adding correction factors to consider the effect of gap size, mass flux, and the number of heating walls. Additional correction factor is added to consider the effect of inlet subcooling. It is shown that the new one is better than the Kaminaga correlation and it is easy to implement to any system code.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2020년도 학술발표회
• /
• pp.114-114
• /
• 2020

Water contamination in a water distribution network (WDN) is harmful since it directly induces the consumer's health problem and suspends water service in a wide area. Actions need to be taken rapidly to countermeasure a contamination event. A contaminant source ident ification (CSI) is an important initial step to mitigate the harmful event. Here, a CSI approach focused on determining the contaminant intrusion possible location and time (PLoT) is introduced. One of the methods to discover the PLoT is an inverse calculation to connect all the paths leading to the report specification of a sensor. A filtering procedure is then applied to narrow down the PLoT using the results from individual sensors. First, we spatially reduce the suspect intrusion points by locating the highly suspicious nodes that have similar intrusion time. Then, we narrow the possible intrusion time by matching the suspicious intrusion time to the reported information. Finally, a likelihood-score is estimated for each suspect. Another important aspect that needs to be considered in CSI is that there are inherent uncertainties, such as the variations in user demand and inaccuracy of sensor data. The uncertainties can lead to overlooking the real intrusion point and time. To reflect the uncertainties in the CSI process, the Monte-Carlo Simulation (MCS) is conducted to explore the ranges of PLoT. By analyzing all the accumulated scores through the random sets, a spread of contaminant intrusion PLoT can then be identified in the network.

• 한국주거학회논문집
• /
• 제26권2호
• /
• pp.39-46
• /
• 2015

The 'pathways' in the Deteriorated Residential Area is the valuable place which represents the history of the community. The 'pathways' is the physical boundary which connects individual environment of private residential area to public environment and which has value as a medium for the definite site for regeneration of Deteriorated Residential Area. Thus, the 'pathways' is considered as the perfect material for the public design for spatial culture to regenerate the Deteriorated Residential Area. However, the most of the public design projects utilize the 'pathways' fragmentarily, there are few systematic studies based on the attribute of the Deteriorated Residential Area. The purpose of this study is the consideration on the attributes of the 'pathways', the detection of the spatial characteristics to find application of the 'pathways', and the cultivation of the baseline data for further research for the spatial nature of the Deteriorated Residential Area. For this study, theoretical consideration is practiced in advance to analyze the meaning of the 'pathways' and Deteriorated Residential Area, the case research is performed using design elements as the analytic frame, and the approach is inferred for systematic public design based on the above result. The objects of case research were chosen among the latest projects implemented in the Deteriorated Residential Area whose subject was 'pathways' and which showed successful result. The characteristics of them were investigated and the details were examined through the homepages of the projects, the reports related to the projects, research material, and interview with the people involved. And to conclude, 'pathways' represents the composition of contents, the space of movement, the formation of community, the landscape design, and the participatory design in the Deteriorated Residential Area. The 'pathways' also finds the proper secondary cultural material for the spatial characteristics and can create the space for the various movements, stay, and communication using the characteristics of movements. The narrow and closed space should be utilized actively to be altered into beautiful space and the Deteriorated Residential Area should be regenerated into coexistent design where people share their lives through sharing spaces.

• 한국작물학회지
• /
• 제48권3호
• /
• pp.248-251
• /
• 2003

콩의 입중에 따른 다수성 콩 품종육성의 엽형 모델을 찾고자 기존의 품종들을 대상으로 일의 형태 및 해부학적 특성과의 관계를 조사했는데. 그 결과를 요약하면 다음과 같다. 1. 엽신의 두께는 소립형 품종보다는 대립형 품종이 두꺼웠으며, 단위엽의 엽면적에서도 대립형 품종들이 큰 경향이었다. 2. 엽육조직의 관찰결과 소립 장엽형 품종과 대립 환엽형품종의 책상세포 및 해면세포가 두껍고 치밀하게 배열되어 있었다. 3. 단위엽면적당 $\textrm{CO}_2$ 흡수량, 주당 $\textrm{CO}_2$ 흡수량, 엽신 및 책상세포의 두께는 종실수량과 정의 상관이 인정되었으며, 단위엽의 엽면적과는 부의 상관을 보였다. 4. 따라서 품종간의 특성은 및 기능의 차이로서 인정할 수 있었으며 특히 $\textrm{CO}_2$ 동화량 및 엽육조직의 두께와 엽육세포의 치밀함 등은 품종간 특성차이를 나타내는데 크게 기여하였다.

• 한국환경과학회지
• /
• 제21권11호
• /
• pp.1307-1320
• /
• 2012

The purpose of this paper is to provide information on planting construction for healthy plant growth. To achieve this purpose, this study analyzed the planting type, planting density, withering rate, soil characteristics, and cambium electrical resistance (CER) of withered trees in an apartment complex with a high withering rate. The major plant groups examined consisted of native broad-leaved tree species (39.3%), native narrow-leaved tree species (24.2%), and native broad-leaved - exotic narrow-leaved tree species (16.4%). The planting density of the green area, where trees were planted from 0.0 to 0.3 trees per unit area, was measured as 98.4%. Withered trees were found in 19 of the 20 planted species, and the withering rate was 41.8% (610 withered/1,461 planted). Withering rates for tree species were measured as follows: Sophora japonica and Salix babylonica (100.0%), Magmolia denudata (84.3%), Lindera obtusiloba (74.7%), cornus kousa (69.3%), acer triflorum (69.2%), diospyros kaki (66.7%), Prunus yedoensis (62.8%), Acer palmatum (52.6%), Prunus armeniaca (51.1%), Chaenomeles sinensis (43.7%), Ginkgo biloba (40.9%), Zelkova serrata (31.0%), Cornus officinalis (28.6%), Taxus cuspidata (25.6%), Pinus densiflora (21.4%), Pinus parviflora (15.2%), Pinus strobus (14.6%), and Abies holophylla (10.3%). Soil chemical analyses for 18 samples revealed that as the withering rate increased, the following occurred: (a) the ratio of silt and clay in soil increased; (b) the soil pH, organic matter rate, nitrogen, available phosphorus, and cation exchange capacity (CEC) in samples were graded as "inadequate," based on the plant grading evaluation; and (c) the NaCl and cation exchange capacity were evaluated as "somewhat satisfactory." The measurement of CER for withering rate shows electrical resistance for higher withering rate are higher, which could predict that a tree will not grow well.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제36권4호
• /
• pp.325-330
• /
• 2010

Introduction: Mini-implant system is applicable to areas of narrow space and area requiring temporary loading support. The purpose of this study was to evaluate the clinical outcome of a mini-implant system as well as the application of mini-implant system in the dental clinical field. Materials and Methods: The patients who had been operated from Jan 2007 to Dec 2007 in the four dental facility including Seoul National University Bundang Hospital were enrolled. To evaluate the factors associated with the clinical outcome, the patients were classified according to gender, age, area of surgery, type of implant, diameter and length of the implant, and the purpose of the mini-implant system application. Results: From 147 implants, only three implants failed, one of them was for temporary loading. There were no serious surgical or prosthetic complications in this study. Conclusion: An analysis of the preliminary data revealed a satisfactory clinical outcome. However, more long-term evaluation of narrow ridge type as well as the patient’s satisfaction on the use of a provisional type mini-implant system is needed.

• 천문학회보
• /
• 제36권2호
• /
• pp.115.2-115.2
• /
• 2011

UWISH2 (UKIRT Widefield Infrared Survey for $H_2$) is an unbiased, narrow-band imaging survey of the Galactic plane in the $H_2$ 1-0 S(1) emission line at $2.122{\mu}m$ using the Wide-Field Camera (WFCAM) at the United Kingdom Infrared Telescope (UKIRT). The survey covers about 150 square degrees of the first Galactic quadrant ($10^{\circ}$ < l < $65^{\circ}$; $-1.3^{\circ}$ < b < $+1.3^{\circ}$). The images have a $5{\sigma}$ detection limit of point sources of K~18 mag and the surface brightness limit is $10^{-19}\;W\;m^{-2}$ $arcsec^{-2}$. The survey operation began on 28 July 2009 and has completed on 17 August 2011. We have been studying the supernova remnants (SNRs) in the UWISH2 survey area. Among the known 274 Galactic SNRs, the survey area includes 65 SNRs or 24 percent of the known SNRs. The wide-field and high-quality UWISH2 images allow us to identify both the diffuse extended and compact $H_2$ emission associated with SNRs, which is useful for understanding their physical environment and evolution. The continuum is subtracted from the narrow-band $H_2$ images using the K-band continuum images obtained as part of the UKIDSS GPS (UKIRT Infrared Deep Sky Survey of the Galactic Plane). So far, we have inspected 42 SNRs, and found distinct H2 emission in 14 SNRs. The detection rate is 33%. Some of the SNRs show bright, complex, and interesting structures that have never been reported in previous studies. In this report, we present our identification scheme and preliminary results.

• Macromolecular Research
• /
• 제16권3호
• /
• pp.212-217
• /
• 2008

PVDF ($Kynar^{(R)}$ 761) nanofibers were made by electrospinning with an external voltage of 6-10 kV, a traveling distance of 7-15 cm and a flow rate of 0.4-1 mL/h. Although the mean diameter of the fibers has not changed significantly, the conditions affected the change in diameter distribution. This was attributed to interactions, both attraction and repulsion, between the positive charges on the polymer solutions and the electrically grounded collector. Higher voltages and traveling distance increased the level of attraction between the positive charge on the polymer solution and the electrically grounded collector, resulting in a narrow diameter distribution, In addition, a high flow rate allowed a high population of uniformly charged solutions to travel to the grounded collector, which resulted in a narrow diameter distribution. The optimum conditions for electrospinning of PVDF in DMAc/acetone (3/7 by wt) were a collector voltage of 6 kV, a syringe tip to collector of 7 cm, a flux rate of 0.4 mL/h and 10 kV, 10 cm, 1 mL/h, Since PVDF is widely used as a filtration membrane, it was electrospun on a PET support with a rotating drum as a grounded collector. Surprisingly, some straight nanofibers were separated from the randomly deposited nanofibers. The straight nanofiber area was transparent, while the randomly deposited nanofiber area was opaque. Both straight nanofibers and aligned nanotibers could be obtained by manipulating the PET drum collector. These phenomena were not observed when the support was changed to an Al sheet. This suggests that a pseudo dual collector was generated on the PET sheet. No negative charge was created because the PET sheet was not a conductive material. However, less charge was created when the sheet was not perfectly attached to the metal drum. Hence, the nanotibers jumped from one grounded site to the nearest one, yielding a straight nanofiber.

• 한국수산과학회지
• /
• 제54권6호
• /
• pp.989-999
• /
• 2021

The sound of finless porpoises Neophocaena asiaeorientalis was recorded with an acoustic recorder to confirm their emergence in the South Sea of South Korea in February, June, and November 2020. Sea water temperature and salinity were also measured. In addition, a sighting survey was conducted to observe the behavior of the finless porpoises and the marine environment, and the clicks of the finless porpoises were recorded every day. The results showed that they always emerged in the survey area. The finless porpoises mainly foraged, whereas some played or rested. The water temperature range of areas where the finless porpoises emerged was 7.5-23.5℃. Assuming that the number of clicks corresponds to the number of finless porpoises, the finless porpoises emerged the most during spring. The emergence decreased during winter and was the lowest during autumn. The finless porpoises emerged more during the daytime than during the nighttime in all seasons, indicating a temporal difference in the usage of the survey area. This might be due to the movement of prey organisms according to regional characteristics. A long-term survey and research on habitat use and environment is needed to manage and conserve the finless porpoises.