• Journal of Korean Society of Forest Science
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• v.76 no.4
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• pp.376-389
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• 1987

Higher fungi (Basidiomycetes) were collected from forest stands of Kwangnung Experimental Forest, Kwangnung, Kyonggido, during the summer and fall seasons of 1976, 1984, 1985 and 1986. A total of 257 species and varieties in 104 genera were identified. Saprophytic fungi accounted for 135 species in 75 genera while mycorrhizal fungi accounted for 120 species in 28 genera. Two parasitic species were collected and they were root parasites. Among the mycorrhizal species Amanita, Russula, Lactarius, and species in the Boletaceae were the dominant taxa. The mycorrhizal fungi appear to be an important component in the essential elements needed for forest management in Korea. A reevaluation of the higher fungi previously described in Korea was made and we report 77 higher fungi previously undescribed from Korea. This is from a single experimental forest and suggests that there are many unreported higher fungi which play an important role in Korean forests.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.65-72
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• 2011

The objective of this research is to develop biomass allometric equation for Pinus densiflora in central region and Quercus variabilis. To develop the biomass allometric equation by species and tree component, data for Pinus densiflora in central region is collected to 30 plots (70 trees) and for Quercus variabilis is collected to 15 plots (32 trees). This study is used two independent values; (1) one based on diameter beast height, (2) the other, diameter beast height and height. And the equation forms were divided into exponential, logarithmic, and quadratic functions. The validation of biomass allometric equations were fitness index, standard error of estimate, and bias. From these methods, the most appropriate equations in estimating total tree biomass for each species are as follows: $W=aD^b$, $W=aD^bH^c$; fitness index were 0.937, 0.943 for Pinus densiflora in central region stands, and $W=a+bD+cD^2$, $W=aD^bH^c$; fitness index were 0.865, 0.874 for Quercus variabilis stands. in addition, the best performance of biomass allometric equation for Pinus densiflora in central region is $W=aD^b$, and Quercus variabilis is $W=a+bD+cD^2$. The results of this study could be useful to overcome the disadvantage of existing the biomass allometric equation and calculate reliable carbon stocks for Pinus densiflora in central region and Quercus variabilis in Korea.

• Journal of The Korean Association For Science Education
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• v.39 no.4
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• pp.545-562
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• 2019

The purpose of this study is to develop cognitive scaffolding tools and to explore their effects on integrated science process skills of high school students. For this purpose, we developed cognitive scaffolding tools including one kind of classroom instruction for training integrated process skills and two kinds of individual learning materials that students can selectively study according to their level of inquiry ability. In addition, we developed hypothetico-deductive inquiry tasks as a tool to investigate the level of students on the integrated process skills for pre-test and post-test respectively. In order to verify the effectiveness of the cognitive scaffolding tools, we conducted inferential statistics on the pre-and post-tests of the experimental group and control group to examine statistical significance of students' inquiry level change depending on the usage of the cognitive scaffolding tools. We also produced Wrightmaps based on Rasch model to compare the change of inquiry ability depending on usage of the cognitive scaffolding tools. As a result, the experimental group using the cognitive scaffolding tools showed a significantly higher scores in all the components of integrated process skills namely, designing inquiry, collecting data, analyzing data, and forming conclusion than the control group. In addition, students who used cognitive scaffolding tools improved their inquiry ability and showed a distinct transition to higher level in each component of the integrated process skills. The results of this study suggest that high school students need cognitive scaffolding to alleviate or eliminate the functional barriers they face in conducting scientific inquiries.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.49-56
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• 2021

Liquefied Petroleum Gas is divided into liquefied gases containing propane (C₃H₈) and butane (C₄H₁₀). The quality of LPG varies greatly depending on the composition of the mixture, so it is important to measure the composition accurately. It is difficult to determine the composition of the mixture because liquid and gas coexist at room temperature. Therefore, the uncertainty in determining the concentration of hydrocarbons by component is high, and there are many problems that differ from the actual content standard. Therefore, it is necessary to develop a mixed liquid propane standard gas for the composition and accurate concentration of hydrocarbon substances. Mixed liquid propane standard gas is manufactured into bellows-type constant-pressure cylinders by ISO-6142 (2015). The homogeneity of the four standard gases manufactured was confirmed to be GC-FID. The manufacturer's uncertainty of expansion was 0.01 % to 0.30 % and homogeneity was 0.03 % to 0.25 %. In this mixed liquid propane standard gas, the relative expansion uncertainty of weight method, manufacturing consistency, cylinder adsorption and long-term stability was developed within 0.26 %-1.3 9% (95% of confidence level, k=2).

• Clean Technology
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• v.27 no.3
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• pp.247-254
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• 2021

In this study, an eco-friendly combustion process of waste 2,4,6-trinitrotoluene (TNT: 2,4,6-trinitrotoluene) was developed, and fundamental data for the quantity of the organic matter in the final combustion residues is presented. Because complete combustion of TNT is not possible theoretically, the combustion process was optimized to reduce organic matter content in the combustion residue by performing measures such as heating time changes, addition of propellant material, and after treatment using a high-temp electrical furnace. From the results, it was confirmed that the organic matter content in the residue could be decreased to 7 ~ 10% with each method. The quantity of the organic matter could be minimized by optimizing the combustion conditions of the process. With only a combustion time increase, the amount of organic matter in the combustion residues was measured at about 9 wt%. The environmental friendliness of the final exhaust gas was also confirmed by real time gas component analyses. In addition, the organic contents could be reduced by a further 2 wt% by applying an additional heat treatment using an external electric furnace after the first incineration treatment. In the combustion process of propellant added waste TNT, it was found that various TNT wastes could be treated using the same eco-friendly protocols because the organic content in the residue decreased in accordance with the amount of propellant. The amount of the organic matter content produced by all these methods fulfilled the requirements under the Waste Management Act.

• Clean Technology
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• v.25 no.1
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• pp.40-45
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• 2019

In this study, nitrous oxide ($N_2O$) emission concentration was measured 3 times continuously for 24 hours from August 27, 2018 to October 22, 2018 and non-dispersive infrared (NDIR) spectrometer was used to calculate $N_2O$ concentration of exhaust gas from municipal solid waste (MSW) incinerator. As a result of $N_2O$ emission characteristics, it is estimated that $N_2O$ emission concentration is due to the difference of furnace temperature, oxygen concentration rather than the chemical component of waste. The measured $N_2O$ emission concentration of MSW incinerator was obtained in the range of 53.6 ~ 59.5 ppm and the total average concentration was measured 55.6 ppm. Therefore, the amount of $N_2O$ emissions calculated from the $N_2O$ concentration was $98.05kg\;day^{-1}$ on average and the amount of $N_2O$ distribution in the range of $90.41{\sim}108.44kg\;day^{-1}$ was obtained. As a result, the $N_2O$ emission factor of the MSW incinerator was estimated to be $1,066.13g_{N_2O}\;ton_{waste^{-1}}$. The estimated $N_2O$ emission factor of the MSW incinerator was 20 times higher than calculated emission factor used in the Tier 2 method. Consequently, it is considered that the method of calculating the amount of $N_2O$ emission in the MSW incineration facilities using waste type and incineration amount needs to be supplemented to ensure accuracy.

• Biomolecules & Therapeutics
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• v.27 no.3
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• pp.327-335
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• 2019

As the elderly population is increasing, Alzheimer's disease (AD) has become a global issue and many clinical trials have been conducted to evaluate treatments for AD. As these clinical trials have been conducted and have failed, the development of new theraphies for AD with fewer adverse effects remains a challenge. In this study, we examined the effects of Theracurmin on cognitive decline using 5XFAD mice, an AD mouse model. Theracurmin is more bioavailable form of curcumin, generated with submicron colloidal dispersion. Mice were treated with Theracurmin (100, 300 and 1,000 mg/kg) for 12 weeks and were subjected to the novel object recognition test and the Barnes maze test. Theracurmin-treated mice showed significant amelioration in recognition and spatial memories compared those of the vehicle-treated controls. In addition, the antioxidant activities of Theracurmin were investigated by measuring the superoxide dismutase (SOD) activity, malondialdehyde (MDA) and glutathione (GSH) levels. The increased MDA level and decreased SOD and GSH levels in the vehicle-treated 5XFAD mice were significantly reversed by the administration of Theracurmin. Moreover, we observed that Theracurmin administration elevated the expression levels of synaptic components, including synaptophysin and post synaptic density protein 95, and decreased the expression levels of ionized calcium-binding adapter molecule 1 (Iba-1), a marker of activated microglia. These results suggest that Theracurmin ameliorates cognitive function by increasing the expression of synaptic components and by preventing neuronal cell damage from oxidative stress or from the activation of microglia. Thus, Theracurmin would be useful for treating the cognitive dysfunctions observed in AD.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.29-42
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• 2018

Shale and mudstone in Daegu-Gyungbuk area have low strength and resistance to weathering compared to other rocks. Therefore, it is necessary to evaluate their strength depending on the degree of saturation and crack development. In this study, shales and mudstones were collected from several construction sites in Daegu-Gyungbuk area. Their basic material properties such as porosity, SEM, chemical component, and durability were tested. A porosity (absorptivity) of mudstone was 31% (25%), which was 6 (8) times higher than that of shale. Some mudstone was easily disintegrated with water and it consisted of highly-active clay mineral such as smectite type. These rocks were prepared by small cube specimens for unconfined compression test. An unconfined compressive strength of dry rock was compared with saturated one. Microwave oven was operated step by step to stimulate void water within a saturated rock, which resulted into high temperature and micro crack initiation within rocks. A strength of microwaved rocks was compared with operation time and crack initiation. As a result, the average unconfined compressive strength of dry and saturated shale was 62 and 33 MPa, respectively. The strength of mudstone for each condition was 11 and 4 MPa. When a rock became saturated, its strength decreased by 47% and 64% for shale and mudstone at average. In addition to saturation, a rock was in the microwave for 15 secs, its strength decreased into 49% for shale and 52% for mudstone. When a microwave oven operated up to 20 sec, a rock was crushed into several pieces and its temperature was approximately 200 degrees.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.286-294
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• 2019

The purpose of this study is to determine what children's rights to play are. For this purpose, we extracted the core contents of schools' play environments and we developed a checklist that schools can use to evaluate their own play environments. We reviewed the UN Committee on the Rights of Children and the General Comments No. 17. Through this process, we found 16 core contents that the play environment should have. We conducted focus group interviews with children, parents and teachers, who are principle people involved with school play. The focus group interviews discussed the basic elements of the school play environment. The contents' validity was reviewed by a group of professionals. Based on this, we created an evaluation checklist with 10 major areas of the school play environment. The 10 areas of the school play environment evaluation scale are as follows. The ten areas of the play environment assessment scale for the school environment to ensure children's right to play are sufficient play time, sufficient play space, a child's best interests and the child's participation, nondiscrimination, diversity and freedom, challenge and adventure, safety, school policy, the play has an educating component, and community cooperation.

• The Journal of the Korea Contents Association
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• v.19 no.3
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• pp.252-260
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• 2019

Smart devices have penetrated deeply into our daily lives. They have not only increased user convenience, but also changed the overall lifestyle of society. The objective of this study was to examine the change process of user experience through device classification and technology by generation. In order to achieve the objective, this study analyzed the purpose and pattern of using a device, which is a digital platform, and the input and output, which are the most important digital components for personal exclusiveness and interaction. The analysis results of this study showed that, in the past, the purpose of using a device was clear, a device was used in common, and a separate device was used for input and output. However, as devices evolved, users began to emphasize the fun aspect than the purpose of a device. As a result, personal exclusiveness has increased. Moreover, unlike devices in the past depending on separate input or output methods, devices are evolving to employ a method performing input and output using the five senses of people such as the touchscreen using a body part of a user, voice, and motion. This study evaluated how the overall experience of users, which was obtained through technology, has changed for each generation. Furthermore, this study proposed the future direction of device development by considering the user experience. It is believed that the results of this study will be useful for future studies on the overall experience of users who will use a range of smart devices, which will be released in the future.