• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.672-677
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• 2001

There was an outbreak of food poisoning due to eating well-cooked imported tropical fish, Stromateus stellatus on May, 2000, in Korea. Gastrointestinal symptoms such as diarrhea ($92\%$), nausea ($77\%$), abdominal pain ($54\%$), vomiting ($46\%$) and headache ($23\%$) were experienced within $0.5\~2$ hours (median 1 hour) after eating, Any specific natural toxins were not confirmed concerned to those poisoning, but large amount of abnormal lipid ($23\%$) was found from the muscle such as 1-O-diacyl glyceryl ethers (DAGE), which was consisted of $61.8\%$ of total lipid. The 16:0 ($66.3\%$) and 18:1 ($15.8\%$) alkyl chains were dominant in all alkyl chains of DAGE which were presumed as the causative agent for the diarrheal food poisoning. O1eic acid (18:1) was found as a major fatty acid at the sn-2 or 3 in DAGEs. O-16:0-18:1-18:1 ($16.2\%$),O-16:0-18:1-22:1 ($14.7\%$) and O-18:0-18:1-22:1 ($11.0\%$) were contained as the major molecular species of DAGEs by RI-HPLC.

• Korean Business Review
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• v.19 no.2
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• pp.69-94
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• 2006

Landfill gas is a mixture of methane and carbon dioxide produced by the bacterial decomposition of organic wastes, and it is considered to produce bad smells and pollute the environment. Economic trials and the developments of landfill gas, as an alternative energy resource, become known at the recent years. Resource development of landfill gas, which is managed by Korea up to now, is for the most part generation using gas engine. Medium BTU and High BTU are considered for the power generation as well. I\10st income of generation using gas engine is selling charge through a power plant. Expecting to manage the power plant for up to 10 years, the analysis based on revenue and expenditure shows when the unit price is 65.2 Won and the operating rate reaches 90%, it is possible to be into the black in 2012 without considering additional financial expense. It was also analyzed that the profit at a unit price of 85 Won under the anticipated rising unit price by the operating rate of 71% is larger than at the operating rate of 90% under limited unit price of 65.2 Won. It means to manage the power plant at a unit price of 65.2 Won and the operating rate must be higher than 90% for economic logicality. If we assume that the operating rate is 90% and it increases the unit price, the unit price must be higher than 85 Won for the management of a power plant. Analysis of changing a unit price, however, might be expected to have a gradual rise of prices. If there is no price rising and additional income related to CDM(Clean Development Mechanism) and emission trading upon Kyoto protocol, the management of a power plant using gas engine will get financial difficulties because of many operating expenses. However, since landfill gas is considered as a worthy energy resource for the guarantee of sustainable development and for the equity between recent generation and future generation, the development of it must be accomplished by the government's additional supporting and efforts under the interest of all stakeholder who are involved.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.789-792
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• 2008

Blast furnace slag doesn't have self-hydraulicity and it needs stimulants such as alkali to hydrate. Therefore using recycled aggregates erupted calcium hydroxides and blast furnace slag acquiring alkali stimulate could make a complementarily use of a recycling architectural material possible. In this study, we have discussed about characters of blast furnace slag and recycled aggregate firstly, and make recycled aggregate mortar and concrete using blast furnace slag for the experiment. The experiment is about mortar and concrete using recycled aggregate as a substitutional material of blast furnace slag. In this experiment, I replace blast furnace slag and aggregate with recycled aggregate. Conclusions through the test results analysis are as follows. And then, we added field experiment using concrete with composited materials.

• Journal of IKEEE
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• v.20 no.1
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• pp.61-67
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• 2016

In this paper, a hardware design method is proposed for high speed high precision neutron radiation measurements. Our system is fabricated to use a high performance A/D Converter for digital data conversion of high precision and high speed analog signals. Using a neutron sensor, incident neutron radiation particles are detected; a precision microcurrent measurement module is also included: this module allows for more precise and rapid neutron radiation measurement design. The high speed high precision neutron measurement hardware system is composed of the neutron sensor, variable high voltage generator, microcurrent precision measurement component, embedded system, and display screen. The neutron sensor detects neutron radiation using high density polyethylene. The variable high voltage generator functions as a 0 ~ 2KV variable high voltage generator that is robust against heat and noise; this generator allows the neutron sensor to perform normally. The microcurrent precision measurement component employs a high performance A/D Converter to precisely and swiftly measure the high precision high speed microcurrent signal from the neutron sensor and to convert this analog signal into a digital one. The embedded system component performs multiple functions including neutron radiation measurement for high speed high precision neutron measurements, variable high voltage generator control, wired and wireless communications control, and data recording. Experiments using the proposed high speed high precision neutron measurement hardware shows that the hardware exhibits superior performance compared to that of conventional equipment with regard to measurement uncertainty, neutron measurement rate, accuracy, and neutron measurement range.

• Journal of the Korea Institute of Building Construction
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• v.17 no.3
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• pp.279-285
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• 2017

In this study, the development of concrete preventing initial frost damage and durability about that were evaluated by using anti-aging agent and admixture(reduced slag). As a result of experiment, initial hydration heat was increased by $C_{12}A_7$ of reduced slag components but it was not effective to development of strength. Also fluidity decreased with increasing replacement of reduced slag. This suggested that fluidity was low by rapid setting due to absent of gypsum in reduced slag components. In case of CR2G specimen that added 4% gypsum, the flow ability was higher than plain. It is considered that concrete developed using reduced slag should use $SO_3$. Result of durability experiments, the durability decreased with increasing replacement amount of reduced slag.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1745-1753
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• 2008

We analyzed the physical and chemical properties such as proximate analysis, ultimate analysis, heating values, thermogravimetric analysis, and combustion test for the organic sludge discharged from chemical and petrochemical product manufacturing industries in the industrial complex. The average combustible and ash content of organic sludges from chemical and petrochemical product manufacturing industries were 17.42%, 7.45%, and 18.25%, 4.22%, respectively. The C, H, O, N, and S compositions for chemical and petrochemical product manufacturing industries were 33.06, 4.34, 24.81, 5.18, and 0.72%. And those compositions for petrochemical product manufacturing industries were 36.58, 4.74, 26.79, 5.09, and 0.49%, respectively. From the TGA test, the minimum temperature for combustion of the sludge discharged from B company was $700^{\circ}C$ for direct use for energy and 2 sludges(F and N companies) were about $600^{\circ}C$. According to the basic combustion test, high concentration of CO was formed because oxidation and pyrolysis reaction take place in the batch type reactor at the same time. From this phenomena we could obtain the significant data for the overheating and breakage of furnace.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1127-1137
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• 2000

Applications of lanthanum ion and crude rare earth chloride to the phosphate wastewater and fluorine wastewater, respectively, as treatment agents were studied. For the investigation of phosphate removal characteristics according to the amount of lanthanum ion, initial phosphate content was decreased by about 50% when molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] was 0.25 and nearly all of phosphate was removed when the molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] to be doubled. The removal of phosphate by $La^{3+}$ appeared to reach equilibrium state rapidly, and it was exothermic reaction since the removed amount of phosphate was diminished somewhat when the reaction temperature was increased. The zeta potential of combined particulate compound of lanthanum ion and phosphate was located for its isoelectric point at pH 5.5 and the turbidity of treated wastewater was found to vary according to the pH in a similar manner as the absolute value of zeta potential of the combined particulate compound did. For the treatment of fluorine wastewater by crude rare earth chloride, the remaining fluorine content after treatment decreased as the dosage of crude rare earth chloride increased. Whereas, the turbidity of treated wastewater and the amount of sludge generated were shown to increase as more crude rare earth chloride was added. The remaining fluorine content and the turbidity of treated wastewater were decreased and the amount of sludge generated was observed to increase according the increase of coagulant dosage under the condition of constant input of crude rare earth chloride.

• Economic and Environmental Geology
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• v.50 no.3
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• pp.251-256
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• 2017

This study presents measures to enhance the efficiency of Successive Alkalinity Producing Systems(SAPS), a natural biological purification method that prevents environmental pollution arising from the release of Acid Mine Drainage(AMD) from abandoned mines into rivers and groundwater. The treatment of AMD using SAPS is based on biological processing technology that mostly involves sulfate reducing bacteria(SRB). It has been proven effective in real-world applications, and has been employed in various projects on the purification of AMD. However, seasonal decrease in temperature leads to a deterioration in the efficiency of the process because sulfate-reducing activity is almost non-existent during cold winters and early spring even if SRB is able to survive. Against this backdrop, this study presents measures to enhance the activity of the SRB of the organic layer by integrating light emitting diode(LED)s in SAPS and to maintain the active temperature using LEDs in cold winters. Given that mine drainage facilities are located in areas where power cannot be easily supplied, solar cell modules are proposed as the main power source for LEDs. By conducting further research based on the present study, it will be possible to enhance the efficiency of AMD treatment under extreme cold weather using solar energy and LEDs, which will serve as an environmentally-friendly solution in line with the era of green growth.

• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.74-80
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• 1984

Storage materials for a minimized storage system should be able to store much energy in small quantities, and to solve such a problem, salt hydrates such as CALCIUM CHLORIDE, SODIUM SULFATE, SODIUM PHOSPHATE etc. were considered as most suitable storage media in which phase change phenomena take place at low temperature. Therefore those salt hydrates were used as storage media in this study, and piped-storage tanks were manufactured vertically for the experiment. The characteristics of thermal storage media were investigated and the results are summarized as follows: 1. From the experiment of radial temperature distribution of vertical piped-storage system, the latent heat phenomenon did not occur in all storage media during heating process because of generations of heat due to the reduction in the number of water molecules. However, among those storage media CALCIUM CHLORIDE had most remarkable latent heat phenomenon during cooling process. Therefore CALCIUM CHLORIDE was considered as most suitable storage media. 2. Heat quantity transferred to the storage media was the largest in case of CALCIUM CHOLORIDE under the same conditions during heating and cooling process.

• Elastomers and Composites
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• v.19 no.1
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• pp.13-31
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• 1984

The purposes of this dissertation are to demonstrate that DSC theromoanaytical methods of vulcanization can provide useful informations on the vulcanization characteristics of industrial formulations and also provides the potential basis for a rapid and complete method of sulfur and vulcanizing accelerator analysis for quality control. The influences of those factors such as heating rate, scan temperature, vucanizing accelerator's type and concentration upon vulcanization exotherm in NR and NBR compounds in the presence of vulcanizing accelerators such as TMTD,MBTS,DPG,TMTM,CBS, and MBT were evaluated by means of DSC. In order to examine the credibility in the DSC method, the same samples which were used for DSC method were studied to compare the DSC results with the ODR (Oscillating Disk Rheometer) data. The results obtained were as follows 1. In the DSC dynamic experiments, the observed enthalpy results from vulcanization depends upon the heating rate; In the range of 2 to $20^{\circ}C/min$ of heating rate, as the heating rate was increased the enthalpy change was also increased. However, over the heating rate of $30^{\circ}C/min$ it was observed that the enthalpy change was decreased as the heating rate was further increased. Without regard to the change of enthalpy, tremendous instantaneous heat evolving was observed in the range of high heating rates. 2. For the samples which are added with various vulcanizing accelerators, the activation energies of vulcanization were as follows; 3. Regarding to the influences of vulcanizining accelerator's types upon the characteristics of vulcanization exotherm, NR and NBR compounds in the presence of thiuramsulphide compounds type accelerators such as TMTD, TMTM, were exhibited sharper and higher vulclanization exotherm than others. From the resuts of DSC thermograms which was distributed in even shape in the broad temperature range, it was clearly shown that the guanidine compounds type accelerator such as DPG acts as a delayed acting accelerator. 4. In the comparison of DSC and ODR results, the dependency of temperature in the cure rate and the observed conversions show good agreements between two results. 5. In the same curatives, by the comparison of glass transition temperatures, it was possible to predict relative values of maximum torques. Consequently, from the present studies, it is shown that the DSC thermoanalytical method can provide an alternate new method for rapid and complete quality control analysis of rubber industry.