• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.304-310
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• 2007

The purpose of this research was to investigate the effects of the co-treatment of municipal wastewater with microwave-irradiated excess sludge on the treatment efficiency and excess sludge production of the activated sludge process. When 250 mL of excess sludge with a MLSS concentration of approximately 2,000 mg/L was microwave-irradiated at $20^{\circ}C$ for $40\sim300$ sec by a microwave oven (2,450 MHz, 700 W), the temperature of the sludge increased at a rate of approximately $20^{\circ}C/min$ and the SCOD, TKN and T-P concentrations of the sludge showed the highest increase in the irradiation time of $40\sim130$ sec. And, the oxygen uptake rate measurement of the sludge microorganism suggested most of the microorganisms in the sludge were destroyed at an irradiation time above 130 sec(above $65^{\circ}C$). When the municipal wastewater and microwave-irradiated excess sludge was co-treated by the activated sludge process, almost no effect was observed in the pH and alkalinity of both the influent and effluent, but the influent concentrations of SS, COD, T-N and T-P increased. Even though the effluent SS, BOD and T-P concentrations showed almost no effect, the COD and TKN concentrations increased. The microbial yield coefficient decreased at a rate of 0.91 g SS/g COD removed as the irradiation ratio increased at a rate of 1 g SS/g SS-day.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.243-249
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• 2011

To reduce manufacturing costs of crystalline silicon solar cells, silicon wafers have become thinner. In relation to this, the properties of the aluminium-back surface field (Al-BSF) are considered an important factor in solar cell performance. Generally, screen-printing and a rapid thermal process (RTP) are utilized together to form the Al-BSF. This study evaluates Al-BSF formation on a (111) textured back surface compared with a (100) flat back surface with variation of ramp up rates from 18 to $89^{\circ}C$/s for the RTP annealing conditions. To make different back surface morphologies, one side texturing using a silicon nitride film and double side texturing were carried out. After aluminium screen-printing, Al-BSF formed according to the RTP annealing conditions. A metal etching process in hydrochloric acid solution was carried out to assess the quality of Al-BSF. Saturation currents were calculated by using quasi-steady-state photoconductance. The surface morphologies observed by scanning electron microscopy and a non-contacting optical profiler. Also, sheet resistances and bulk carrier concentration were measured by a 4-point probe and hall measurement system. From the results, a faster ramp up during Al-BSF formation yielded better quality than a slower ramp up process due to temperature uniformity of silicon and the aluminium surface. Also, in the Al-BSF formation process, the (111) textured back surface is significantly affected by the ramp up rates compared with the (100) flat back surface.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.181-184
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• 2009

Purpose: Automated system that immunoassay examination are used widely. However, sample to sample carryover can cause that the next patient sample is false positive. Materials and Methods: We test HBs Ag, HBs Ab, HBc Ab(IgG) with Automated pipetting system (Tecan). It was placed with very high concentrations followed by saline solution. During this experiment, The fixed tip of Automated system wash With 0.25 moL/L NaOH. The Measurement results of saline solution confirm the occurrence of carryover. Results: Results of saline solution with 0.25 moL/L NaOH cleaning process was measured 100% negative, And results of patient serum with 0.25 moL/L NaOH cleaning process is similar reported results. Conclusion: As Results, 0.25 moL/L NaOH cleaning process was avoid carryover in experiment, And we know results of the hepatitis test did not affected by this solution we recommend 0.25 moL/L NaOH cleaning process as the Prevention of carryover in the automated system with fixed Tips.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.281-295
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• 2010

A new, automated apparatus is proposed for calculating the Soil-Water Characteristic Curve (SWCC), representing a simple and easily applied testing device for continuous measurements of the volumetric water content and suction of unsaturated soils. The use of this apparatus helps to avoid the errors that arise when performing experiments. Consequently, the apparatus provides greater accuracy in calculating the SWCC of unsaturated soils. The apparatus is composed of a pressure panel, flow cell, water reservoir, air bubble trap, balance, sample-preparation accessories, and measurement system, among other components. The air pressure can attain 300 kPa, and a general test can be completed in a short time. The apparatus can simply control the drying process and wetting process. The changes in volumetric water content that occur during the drying and wetting processes are shown directly in the SWRC program, in real time. As a case study, we performed an SWCC test of Joomunjin sand (75% relative density) to measure matric suction and volumetric water content during both the drying and wetting processes. The test revealed hysteresis behavior, whereby the water content on the wetting curve is always lower than that on the drying curve for a specific matric suction, during the wetting and drying processes. Based on the test results, SWCCs were estimated using the Brooks and Corey, van Genuchten, and Fredlund and Xing models. The van Genuchten model performed best for the given soil conditions, as it yielded the highest coefficient of determination.

• Information Systems Review
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• v.12 no.2
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• pp.145-166
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• 2010

As the service industry is advancing, the meaning of service innovation has been evolved. Recently, service innovation embraces all creative activities about service offering or relevant to service offerings and emphasizes the importance of customers in innovation process as a key driver. The innovation in services is often the result from a collaborative process between KIBS firms and client firms. Many researchers have pointed out about how the KIBS firms drive the innovation through service. In spite of the importance of service innovation, previous studies did not address the questions about what kinds of factors affect service innovation in KIBS firms still remain, or what are the effects of different knowledge on the innovation process. Therefore, the purpose of this study is to investigate the effect of the interactivity that KIBS firms have with their customers on various types of innovations in KIBS firms. Interactivity has been touted to be the most important starting point for and the basis of service innovations. This study also examines the effect of knowledge types (tacit or explicit) on the relationship between interactivity and service innovation. To test the proposed hypotheses, we developed measurement items and distributed survey questionnaires to domestic companies. 230 survey questionnaires were distributed and 81 were returned among which 76 were usable. The results of this study show that interactivity may be a significant indicator of innovation within KIBS firms. It also represents that the effect of knowledge types on the relationship between interactivity and innovation. These results indicate that KIBS firms need to improve the various activities of interaction with customers for innovation. This study provides a blueprint to further investigation of the critical role of service in service science perspectives.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.603-612
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• 2006

Recently the web service area is rapidly growing as the next generation IT paradigm because of increase of concern about SOA(Services-Oriented Architecture) and growth of B2B market. Since a service discovery through UDDI(Universal Description, Discovery and Integration) is limited to a functional requirement, it is not considered an effect on frequency of service using and reliability of mutual relation. That is, a quality as nonfunctional aspect of web service is regarded as important factor for a success between consumer and provider. Therefore, the web service selection method with considering the quality is necessary. This paper suggests the agent-based quality broker architecture and selection process which helps to find a service providing the optimum quality that the consumer needs in a position of service consumer. A theory of agent is accepted widely and suitable for proposed system architecture in the circumstance of distributed and heterogeneous environment like web service. In this paper, we considered the QoS and CoS in the evaluation process to solve the problem of existing researches related to the web service selection and used PROMETHEE(Preference Ranking Organization MeTHod for Enrichment Evaluations) as an evaluation method which is most suitable for the web service selection among MCDM approaches. PROMETHEE has advantages that solve the problem that a pair-wise comparison should be performed again when comparative services are added or deleted. This paper suggested a case study with the service composition scenario in order to verify the selection process. In this case study, the decision making problem was described on the basis of evaluated values for qualities from a consumer's point of view and the defined service level.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.348-348
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• 2011

Carbon nanotube (CNT) field effect transistors and sensors use CNT as a current channel, of which the resistance varies with the gate voltage or upon molecule adsorption. Since the performance of CNT devices depends very much on the CNT/metal contact resistance, the CNT/electrode contact must be stable and the contact resistance must be small. Depending on the geometry of CNT/electrode contact, it can be categorized into the end-contact, embedded-contact (top-contact), and side-contact (bottom-contact). Because of difficulties in the sample preparation, the end-contact CNT device is seldom practiced. The embedded-contact in which CNT is embedded inside the electrode is desirable due to its rigidness and the low contact resistance. Fabrication of this structure is complicated, however, because each CNT has to be located under a high-resolution microscope and then the electrode is patterned by electron beam lithography. The side-contact is done by depositing CNT electrophoretically or by precipitating on the patterned electrode. Although this contact is fragile and the contact resistance is relatively high, the side-contact by far has been widely practiced because of its simple fabrication process. Here we introduce a simple method to embed CNT inside the electrode while taking advantage of the bottom-contact process. The idea is to utilize a eutectic material as an electrode, which melts at low temperature so that CNT is not damaged while annealing to melt the electrode to embed CNT. The lowering of CNT/Au contact resistance upon annealing at mild temperature has been reported, but the electrode in these studies did not melt and CNT laid on the surface of electrode even after annealing. In our experiment, we used a eutectic Au/Al film that melts at 250$^{\circ}C$. After depositing CNT on the electrode made of an Au/Al thin film, we annealed the sample at 250$^{\circ}C$ in air to induce eutectic melting. As a result, Au-Al alloy grains formed, under which the CNT was embedded to produce a rigid and low resistance contact. The embedded CNT contact was as strong as to tolerate the ultrasonic agitation for 90 s and the current-voltage measurement indicated that the contact resistance was lowered by a factor of 4. By performing standard fabrication process on this CNT-deposited substrate to add another pair of electrodes bridged by CNT in perpendicular direction, we could fabricate a CNT cross junction. Finally, we could conclude that the eutectic alloy electrode is valid for CNT sensors by examine the detection of Au ion which is spontaneously reduced to CNT surface. The device sustatined strong washing process and maintained its detection ability.

• Analytical Science and Technology
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• v.16 no.5
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• pp.368-374
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• 2003

Halogen gases such as $BCl_3$ and $CF_4$ are among the most problematic gases used in semiconductor process. They raise serious environmental and health problems due to their extreme toxicity. This study is to develop a method to effectively remove those gases during the process by using various types of inorganic gas adsorption agents such as zeolite A, modified AgA zeolite, ZnO, and $AgMnO_3$, which have not been attempted in the conventional methods. The removal efficiencies of the gases were both qualitatively and quantitatively measured by a FT-IR spectrophotometer. The whole device for the measurement has been designed and built in our lab. The removal efficiencies of the gases were compared between those used resins. The experimental result revealed that ZnO showed the best removal efficiency for BCl3 gas that had removed 0.094 g per 1 g of the resin used. For $CF_4$ gas, none of the solid resins was able to remove the gas effectively. However, liquid $CHCl_3$ showed some removal ability of the $CF_4$ gas.

• Journal of Conservation Science
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• v.29 no.4
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• pp.297-309
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• 2013

Iron objects become corroded at fast speed from the moment when they are excavated, so it is needed to control corrosion through processes of conservation treatment. However, re-corrosion mostly takes place in excavate iron objects, although they have already gone through the process of conservation treatment, and it is more difficult to carry out the second conservation treatment of re-corroded excavated iron objects than the first conservation treatment, and it requires a longer period of time to treat them as well. In this study, aims to discover factors of re-corrosion by scientifically analyzing corrosion products generated during the process of storage after the process of conservation treatment. The finished on conservation treatment of the iron artifacts, which were unearthed from three ancient site in Gyeongju by using the same conservation method between 2002 and 2009, re-corrosion condition observed on the packaging-iron artifacts. Focused on 9 target forged iron artifacts among them, this study analyzed the physical changes by mass measurement, naked-eye and microscopic observations and the chemical changes by SEM-EDS, XRD, IC and ICP analysis. The results show that the yellowish brown corrosion products formed on the facing surface of part dropped from the artifacts had different associated forms but acicular shape. In addition, the acicular shape became clearer as the color changed from red to yellowish brown. According to the process when the conservation treatment was completed, the mass of the artifacts increased in proportion to the corrosion products and the chloride ion ($Cl^-$) concentration had a tendency to increase relatively. ${\beta}$-FeOOH (akaganeite) was confirmed in the XRD analysis for the corrosion products of all the collected samples. As a result of ICP analysis, $Na^+$ and $Ca^{2+}$ components were confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.448-453
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• 2016

Erosion and abrasion caused by cavitation damage occur in fluid equipment, such as ships or impellers. Similarly, the equipment damage from noise and vibration can shorten its life. This study analyzed the importance of the parameter characteristics of the process optimization of HVOF (High Velocity Oxygen Fuel spraying), which is generally used in a variety of industries for enhancing the resistibility from the cavitation phenomenon. The surface of the ALBC3 substrate was coated with an amorphous powder as a filler metal according to the experimental design using the Taguchi method, and then the characteristics with each parameter were analyzed using a porosity measurement test. The optimal process conditions was a combustion pressure of 80psi, coating distance of 270mm, gun speed of 200mm/s, and powder feed rate of 25g/min as a result of the HVOF coating by applying the experimental design. The combustion pressure, coating distance and powder feed rate were more than 25% and indicated a similar contribution rate, but the contribution rate of the gun speed was 19%, which was slightly less than the others. The contribution rate with each parameter was only slightly significant. On the other hand, all four parameters were found to be important in the contribution rate aspects of the HVOF coating process.