• 한국환경과학회지
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• 제10권1호
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• pp.41-45
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• 2001

This study was carried out to investigate phytoplankton community structure in the Naktong river from January to December in 1999. In water quality, average value of pH were 8.1, BOD 2.5mg/$\ell$, COD 5.0mg/$\ell$, Chl-a 41$\mu\textrm{g}$/$\ell$, and $NH_4^+-N$ 0.08mg/$\ell$, respectively. Phytoplankton were identified 42 genera 76 species. Among these, diatoms were 39 species(51.3%), green algae 25 species(32.9%), cyanobacteria 4 species(5.3%), dinoflagellates 4 repectively. The highest standing crops were 33,023 cells/$m\ell$ in February at the Mulgum and the lowest 79 cells/$m\ell$ in March at the Goryung. Also, Standing crops were increased with proceeding from middle part to lower part. Seasonal succession of phytoplankton represented that Stephanodiscus hantzschii was dominant species in winter, Cyclotella menaghiniana and Synedra acus in spring, C. meneghiniana, S. acus, Aulacoseira granulata var. angustissima in summer, and A. granulata var. angustissima and C. meneghiniana in autumn. Ecological important species were 4 species, that are Stephanodiscus hantzschii, Cyclotella meneghiniana, Synedra acus, and Aulacoseira granulata var. angustissima. In the community analysis, dominance indices ranged from 0.434(August, Namji) to 0.999(January, February, Mulgum) and diversity indices from 0.026(February, Mulgum) to 3.073(September, Namji). According to the similarity index among the stations, it was generally defind as two areas such as middle(Goryung, Namji and Samryangjin) and lower part(Mulgum).

• Advances in concrete construction
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• 제9권6호
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• pp.577-588
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• 2020

In this paper, vibration attributes of chiral double-walled carbon nanotubes (CNTs) based on nonlocal elastic shell model have been investigated. The impact of small scale is being perceived by establishing Flügge shell model. The wave propagation is engaged to frame the ruling equations as eigen value system. The influence of nonlocal parameter subjected to different end supports has been overtly examined. A suitable choice of material properties and nonlocal parameter been focused to analyze the vibration characteristics. The new set of inner and outer tubes radii investigated in detail against aspect ratio and length. The dominance of boundary conditions via nonlocal parameter is shown graphically. Whereas for lower aspect ratio the frequencies coincide but as it continues to expand the difference between all respective boundary conditions slightly tend to increase. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

• 대한기계학회논문집B
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• 제25권11호
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• pp.1500-1508
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• 2001

This paper represents the importance of dependent variables in non-orthogonal curvilinear coordinates just as the importance of those variables of convective scheme and turbulence model in computational fluid dynamics. Each of Cartesian, physical covariant and physical contravariant velocity components was tested as the dependent variables of momentum equations in the staggered grid system. In the flow past a circular cylinder, the results were computed to use each of three variables and compared to experimental data. In the skewed driven cavity flow, the results were computed to check the grid dependency of the variables. The results used in Cartesian and physical contravariant components of velocity in cylinder flow show the nearly same accuracy. In the case of Cartesian and contravariant component, the same number of vortex was predicted in the skewed driven cavity flow. Vortex strength of Cartesian component case has about 30% lower value than that of the other two cases.

• 한국연초학회지
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• 제22권1호
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• pp.25-30
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• 2000

Bacterial wilt(Ralstonia solanacearum) is one of the major diseases of flue-cured tobacco (Nicotiana tabacum L.) in the world. This study was conducted to investigate degree of dominance, selection, and correlation between leaf shape and degree of bacterial wilt resistance in flue-cured tobacco. The degree of disease caused by bacterial wilt was evaluated in parents, F$_1$, F$_2$ and F$_3$ populations of two crosses, BY 4 x NC 95 and BY 4 x Coker 86, in the infected field. The leaf shape index was also measured in parents and F$_2$ population of BY 4 x NC 95. The incidence of bacterial wilt was observed in the middle of June and peaked in late July, when the highest value of pathogen density reached 1.0 x 10$^{6}$ colony forming unit per gram. It was concluded that the inheritance mode of risestance to bacterial wilt in the above two crosses of susceptible and resistant varieties was recessive and polygenic. The resistance to bacterial wilt was significantly correlated with leaf shape in F2 generation of BY 4 x NC 95. But certain plants having narrower leaves were also resistant to bacterial wilt. It is considered that the bacterial wilt resistant lines having narrower leaves could be selected. The selection for bacterial wilt resistance in the F$_2$ population might be effective.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 1997년도 한국감성과학회 연차학술대회논문집
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• pp.224-227
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• 1997

The International Affective Picture System (IAPS) developed by Lang and colleagues[1] is a world-widely adopted tool in studices relating a variety of physiological indices to subjective emotions induced by the presentation of standardized pictures of which subjective ratings are well established in the three dimensions of pleasure, arousal and dominance. In the present stuey we investigated whether distinctive EEG characteristics for six discrete emotions can be discernible using 12 IAPS pictures that scored highest subjective ratings for one of the 6 categorical emotions, i. e., happiness, sadness, fear, anger, disgust, and surprise (Two slides for each emotion). These pictures as visual stimuli were randomly given to 38 right-handed college students (20-26 years old) with 30 sec of exposure time and 30sec of inter-stimulus interval for each picture while EEG signals were recorded from F3, F4, O1, and O2 referenced to linked ears. The FFT technoque were used to analyze the acquired EEG data. There were significant differences in RP value changes of EEG bands, most prominent in theta, between positive positive and negative emotions, and partial also among negative emotions. This result is in agreement with previous studies[2, 3]. However, it requires further studied to decided whether IAPS could be a useful tool for catigorical approaches to emotion in addition to its traditional uwe, namely dimensional to emotion.

• 한국항만경제학회지
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• 제22권1호
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• pp.61-86
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• 2006

As the economic volume and trade in North-East Asia have dramatically increased, the competition for dominance over the value of logistics among many developed countries has taken a new turn. The Korean government has been planning a strategy for a north-east asian logistics hub in order to increase the global competitiveness of manufacturing companies by promoting a logistics industry. However, the competitiveness of Korean logistics industry is still quite premature compared to global competitors. Taking these accounts into considerations, this study advocates that the structure of Korean logistics companies should be changed from the function of furnishing simple logistics to extending integrated logistics services. It should also shift its focus from executing domestic logistics to meeting international logistics demands and from an execution-focused service to a knowledge-intensive service. The purpose of this study is to explore effective methods for stimulating an integrated logistics industry. Some detailed guidelines and economic interpretations, based upon the results of this research, have been suggested for supporting the related legislation.

• The Korean Journal of Ecology
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• 제12권4호
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• pp.285-295
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• 1989

This report is results of an investigation on the secondary succession and species diversity of the burned area. Fifty hectares of pine forest was burned by the crown fire of the spring (April 6) 1986. The results obtained from spring 1989 were summarized as follows: In the burned area , site and unburned area (U), the vascular plant fo 69 kinds, 49 kinds and 24 kinds were lsted respectively. The life form spectrum of burned area was H---e type, which is common type in most burned area and that unburned area, H---e type. The species diversity (H)and evenness index (e) of burned area (, site) were H=2.51, 1.65 and e=0.59, 0.44 and those of unburned area (U) were H=1.28 and e=0.40. The similarity index was the value of 0.594 in - and 0.236 in -U site. The similarity between and site was greater than between site and U site, and that between and U-site, The dominance index (c) of , and U-site was 0.16, 0.39 and 0.42 respectively. The succession degree (DS) of , and U-site was 244.0, 227.6 and 854.4 respectively. Soil pH, available phosphorous, and exchangeable potassium in the burned area were higher than those in the unburned area, and total nitrogen, organic carbon, and C/N ratio in the burned area were higher than those in the unburned area, and organic matter in the burned area was higher than that in the unburned area.

• 한국환경생태학회지
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• 제20권2호
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• pp.103-113
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• 2006

월출산국립공원 묵동지역에 대해 30개 조사지(단위면적 $100m^2$)를 설정하여 식생구조를 파악하였다. TWINSPAN을 이용하여 군락분리를 시도한 결과, 굴참나무-신갈나무군락, 굴참나무군락, 굴참나무-소나무군락, 소나무군락 그리고 상수리나무군락의 5개 군락으로 최종 분리되었다. 각각의 군락은 상대우점치를 이용하여 군락구조를 밝혔다. 이상의 결과를 통해 월출산국립공원 묵동지역의 식생천이는 소나무림에서 참나무림으로 진행될 것으로 예상된다.

• 한국분무공학회지
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• 제24권3호
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• pp.105-113
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• 2019

In this paper, a study of Urea-SCR System for Dosing Injector for responding to enhanced environmental regulations has been conducted. There is a limit to the experimental approach due to the structural characteristics of the injector. In order to overcome this problem, The analysis was performed assuming unsteady turbulent flow through computational fluid analysis and the internal flow characteristics of the injector were analyzed. By changing the nozzle shape of the injector, the performance factors of the swirl injector by shape were selected and compared. The design parameters were modified by changing the diameter of the nozzle at a constant ratio compared to the base model. Swirl coefficient, outlet mass flow, and sac volume were selected as performance parameters of the injector. The Conv. model to which the taper was applied showed the dominance in mass flow rate, discharge coefficient and swirl because of the smooth fluid flow by shape. Swirl coefficient, outlet mass flow, and sac volume were selected as performance parameters of the injector. As a result of the comparison coefficient derivation with those performance parameters for comparing the performance of the model-specific injector, the Conv-140 model with the nozzle diameter expanded by 140% showed the best value of the comparison coefficient.

• 한국환경복원기술학회지
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• 제24권3호
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• pp.19-31
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• 2021

The waste landfill that has been used as a park through a stabilization project to provide green space to local residents. Vegetation restoration is necessary for the landfill park project, but it is difficult to restore vegetation due to various disturbances in the landfill. This study analyzed the successional dynamics and ecological characteristics of Robinia pseudoacacia communities from the slopes of Noeul Park by applying the 7-stage successional hypothesis. As a result of the study, there was almost no intermediate successional stage. There are only the early successional stage which Robinia pseudoacacia has an absolute dominance of 100% in the crown and middle layers, and the degeneration successional stage which formed by the introduction of Morus alba. This result showed that the succession of Robinia pseudoacacia communities were not able to proceed to the climax forest due to various disturbances in the waste landfill. Therefore, it was analyzed that it is necessary to induce the succession through intermediate steps such as Morus alba, since it is difficult to transition from Robinia pseudoacacia community to the native Quercus spp. community.