• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.163-168
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• 2016

In this study, we analyzed the empty body weight and nominal volume of different types of polyethylene terephthalate (PET) bottles commercialized in Korean market. Over 780 PET bottles were collected and classified into four types, heat resistance bottle, normal resistance bottle, pressure resistance bottle, and long period using bottle. Each PET bottle's lightness index was established using bottle weight and nominal volume. Based on the index value, "acceptable" and "optimum" criteria for design guideline of PET bottle were summarized for each PET bottle type. In this paper, we suggest the use of PET bottle lightness index as a design guideline for material resource reduction of PET bottle for Korean beverage industries and bottle makers. For example, we can achieve 2~4 g weight reduction in normal pressure bottle for 500 mL drinking water.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.381-391
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• 2017

The purpose of this study is to investigate the effect of optimism on stress on happiness index. The subjects were 3 and 4 grade students who had clinical practice experience among 3 nursing students at G university, and 362 questionnaires were used as research data. The data analysis used regression analysis, SPSS macro and bootstrapping methods to examine the mediating effects of optimism on college students' stress and happiness. The results showed that stress, happiness, and optimism were significantly correlated, and stress had a direct effect on college students' happiness. In other words, the higher the level of stress, the lower the happiness index of college students. The optimism was partially mediated between stress and college students' happiness index. Therefore, in order to increase the happiness index of college students, it is necessary to develop and implement a program for happiness enhancement as one of the program strategies that can enhance stress.

• Journal of Periodontal and Implant Science
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• v.28 no.3
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• pp.465-475
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• 1998

The purpose of this study was to investigate the comparative effects of subgingival irrigation using some oral mouth rinses on early healing process of periodontal inflammation. The study population consisted of 13 patients with periodontal inflammation and distributed into 4 groups. Oral hygiene instruction, delicate scaling and root planing were done and then irrigated per 3 days during 2 weeks in situ with 1 of 4 solutions ; normal saline, C31G, Benzotonium chloride and tetracycline. Examination regarding probing pocket depth, plaque index, sulcular bleeding index, gingival index, gingival recession and leukocytes differential count was performed. Evaluation was made at the baseline and 2 weeks after non-surgical periodontal therapy. The results were as follows : 1. Clinical indices including probing pocket depth, plaque index, sulcular bleeding index, gingival index and gingival recession were significantly improved from baseline to 2 weeks. But there was no significant differences among 4 groups. 2. PMNs percent on leukocytes differential count was significantly decreased from baseline to 2 weeks on all groups. Those of tetracycline and C31G were significantly decreased than those of normal saline group. These results suggest that clinical indices were not different, but the decrease of inflammation were significantly different among some mouth rinses.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.184-201
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• 2011

This study was carried out to investigate the distribution status and invasional characteristics of the naturalized plants. The vascular plants in these areas were consisted of total 381 taxa: 81 families, 234 genera, 295 species, 2 subspecies, 66 verieties, 18 forms. Among the investigated vascular plants, naturalized plants (Sicyos angulatus, Barbarea vulgaris, Thlaspi arvense, Amorpha fruticosa, Trifolium pratense, Ambrosia artemisiifolia, Ambrosia trifida, Aster pilosus, Rumex acetosella etc.) were 41 taxa. The Naturalization Index (NI) was 10.70% and the Urbanization Index (UI) was 15.30% at Chuncheon city. The Invasion Index was 63.41% at urban river and 97.56% at stream high, 19.51% at urban forest area.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.388-396
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• 2023

The evaluation of fire risk for combustible materials was carried out using Chung's equations-X, Chung's equations-XI, and Chung's equation-XII, which were newly established. The fire risk index-XII (FRI-XII) and fire risk rating (FRR) were calculated for specimens including camphor tree, cherry, rubber tree, and elm. The combustion characteristics were determined using a cone calorimeter according to ISO 5660-1. Chung's equations caculated the fire performance index-X (FPI-X) and fire growth index-X (FGI-X) values ranged from 89.34 to 1696.75 s² /kW and from 0.0006 to 0.0107 kW/s² , respectively. In addition, the fire performance index-XI (FPI-XI) and fire growth index-XI (FGI-XI) varied from 0.08 to 1.48 and from 0.67 to 11.89, respectively. The fire risk index-XII (FRI-XII), which is an indicator of fire risk, showed that camphor tree had a value of 148.63 (fire risk rating: G), indicating a very high fire risk. This suggests that combustible materials with a high concentration of volatile organic compounds have lower FPI-X and FPI-XI values, higher FGI-X and FGI-XI values, and consequently higher FRI-XII values, indicating an increased fire risk.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.3
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• pp.288-297
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• 1999

This study has been carried out in order to measure the thickness of soft-tissue on lateral cephalographs based on body mass index(BMI) and the change in soft-tissue thickness after surgical correction of mandibular protrusion. The control material in cephalometric study comprised students at The Dental College, 38 persons, aged 21~24 years and the patient material comprised 20 women and 12men, aged 19~28 years with mandibular protrusion.The thickness of the soft-tissue based on BMI in control and study groups, the comparison between them, immediate postoperative change in the thickness, 6 months after surgery, ratio of soft-tissue response and correlation was established through various statistical methods. The result were as follows : 1. The groups based on BMI showed significant differences each other as regards the linear measurements. The thickest soft-tissue was measured 13.6mm, 15.47mm, 16.76mm at Ss, the thinnest at G' 6.0mm, 6.7mm, 7.26mm respectively. 2. The differences between control and experimental groups based on BMI showed to be significant. There were no differences at G'. The soft-tissue in prognathic patients was thicker at Ss, Ls and thinner at Li, Ls, Pg', Gn', Me'. Differential gap was greater in overweight groups. 3. The immediate soft-tissue change after surgery showed the increase at Li, Ls, Pg', Gn', Me' except G', Ls in all groups. 4. The postoperative soft-tissue change 6 months after surgery was similar with immediate change. The soft-tissue shows the increase in the thickness at Li, Pg', Gn', Me' and the greatest difference occurred at Li, 1.1mm, 0.98mm, 1.2mm respectively. 5. The patients with lower BMI index showed higher soft-tissue response to bony movement at Pg'. The immediate response ratio was 91%, 87%, 81% in A,B,C groups respectively, the response 6 months after surgery showed 96%, 91%, 84%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.768-775
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• 2015

Seasonal variability in the marine seaweed community structure was examined in the intertidal zones at nine study sites in Hallyeohaesang National Park, on the southern coast of Korea from March to October 2014. A total of 145 seaweeds were indentified, comprising 15 green, 41 brown and 89 red algae. Coarsely branched seaweeds were the dominant functional group, comprising 58.95% in species number, whereas filamentous, sheet, thick leathery, crustose and jointed calcareous forms comprised 2.63-17.72% each. The seaweed biomass averaged 358.00 g dry wt/m² and it was maximal at Somaemuldo (847.64 g dry wt/m²) and minimal at Gamam (56.51 g dry wt/m²). Based on biomass, the dominant and subdominant seaweeds were Ulva australis at Gamam, Sargassum thunbergii at Sangju, Ulva australis and S.fulvellum at Neukdo, S.horneri at Dala-Bijindo-Somaemuldo, S. thunbergii at Dapo, and Corallina pilulifera at Songdo. Community indices were as follows: dominance index (DI), 0.43-0.71; richness index (R), 8.26-16.50; evenness index (J'), 0.36-0.54; and diversity index (H'), 1.57-2.19. In conclusion, we found that both biomass and the community structure of seaweeds in Hallyeohaesang National Park were similar to those in other studies of the Southern Sea along the Korean peninsula, and that Hallyeohaesang National Park is a relatively favorable habitat for seaweeds. Future studies should examine the changes in seaweed composition and biomass as they relate to climate change and environmental pollution.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.55-64
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• 2017

Seasonal variability in algal community structure was examined at the intertidal zones of five study sites on the Taean Peninsula, on the western coast of Korea, from February 2014 to November 2015. A total of 118 species of marine algae, comprising 17 green, 24 brown and 77 red algae, were identified. The maximum number of species was observed at the Mohang site (75 species), and the minimum at the Yeonpo site (46 species). The seaweed biomass was $160.24g\;dry\;wt./m^2$ on average, and was maximal at Uihang ($519.04g\;dry\;wt./m^2$) and minimal at Yeonpo ($19.03g\;dry\;wt./m^2$). Based on biomass, the dominant seaweeds at Taean peninsula were Sargassum thunbergii and Corallina pilulifera. Community indices were as follows: richness index (R), 3.21-5.01; evenness index (J'), 0.33-0.38; and diversity index (H'), 0.90-1.12. Based on evaluation of the environmental states by the community indices, the ecological evaluation index (EEI) of Taean peninsula was "moderate". The overall species and biomass of seaweeds decreased after the oil spill. However, Hakampo previously showed a similar algal community structure. In conclusion, the algal community was temporarily affected by the oil spill, but rapidly recovered.

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.204-217
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• 2022

Background: Increasing land demands for food production have led to biodiversity loss and land degradation in the Madhupur Sal forest. Reforestation activities such as agroforestry and woodlot plantation support the conservation of diversity, restoration of forest and prevention of soil erosion in degraded natural Sal forest. Knowing about these reforestation activities, this study is needed to compare the species composition, richness, and soil nutrients of these two plantation activities to the natural Sal forest in the degraded Madhupur Sal forest in Bangladesh. Results: The analysis showed that in between the reforestation activities, the highest Shannon-Wiener index (1.79), evenness (0.60) and Simpson's index (0.79) were found in the agroforestry site compared to the woodlot plantation site. On the contrary, the highest species richness (n = 14), tree basal area (19.56 m² ha^-1), Margalef's index (1.96) were recorded in woodlot plantation than in the agroforestry site. We observed that at 0-15 cm depth, soil organic matter (2.39%), total nitrogen (0.14%), available phosphorous (62.67 ㎍ g^-1) and exchangeable potassium (0.36 meq/100 g) in agroforestry plots were significantly higher compared to other forest sites. At topsoil (15-30 cm depth), soil organic matter (1.67%) and available phosphorous (21.09 ㎍ g^-1) were found to be higher in agroforestry site. Conclusions: Both reforestation approaches improved soil function, although woodlot plantation had the higher species richness. Therefore, plantation activities by the sustainable implementation of these two practices are the best alternative to restore the biodiversity, richness and conserve soil fertility in the Madhupur Sal forest of Bangladesh.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.144-154
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• 2011

The fish community structure and inhabiting status of the endangered species Gobiobotia macrocephala and G. brevibarba were investigated at 10 stations in the Seom River, Korea from spring to autumn in 2010. During the survey, 37 species belonging to 10 families were found as inhabitants. A dominant species was Zacco platypus (36.2%), subdominant species were G. macrocephala (13.2%) and G. brevibarba (12.2%), and predominant species were Coreoleuciscus splendidus (8.1%) and Rhinogobius brunneus (4.9%). In addition, 18 species were endemic species to Korea; G. brevibarba and G. macrocephala were endangered species. The similarity index based on species composition and numbers clearly separated fish communities in the Seom River according to main sections, i.e., upper section (St. 1~3), middle section (St. 4~6) and lower section (St. 7~10). Dominance index gradually decreased toward the lower section, while diversity and species richness index gradually increased toward the downstream section. G. macrocephala resided in a fast-running downstream riffle with pebble and cobble substratum, while G. brevibarba inhabited the entire riffle with cobble substratum.