• Clean Technology
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• v.27 no.3
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• pp.255-260
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• 2021

A drawback in the CO₂ capture process using an aqueous amine solution is the high energy requirement for the regeneration process. In order to overcome this disadvantage, this study investigated CO₂ capture characteristics using a biphasic absorbent in which isopropanol (IPA) was introduced into an aqueous solution of diethylenetriamine (DETA). When the IPA composition exceeded 20 wt% in 20 wt% DETA aqueous solution, the absorbent phase was liquid-liquid separated into a CO₂-rich phase and a CO₂-lean phase because of the low solubility of the salt formed by the reaction of CO₂ with DETA in isopropanol. When the isopropanol composition in the DETA aqueous solution increased, the phase volume ratio of the CO₂-rich phase to the volume of the CO₂-lean phase increased; and, accordingly, the CO₂ in the CO₂-rich phase was more concentrated. The results of absorbing CO₂ in a packed tower using 20 wt% DETA + IPA + water absorbent confirmed that both the CO₂ absorption capacity and the absorption rate were higher than that of the 20 wt% DETA aqueous solution. When a biphasic absorbent composed of DETA + IPA + water is applied to CO₂ capture, it can be expected to concentrate CO₂ because of phase separation and thereby reduce regeneration energy owing to volume reduction of the CO₂-rich phase.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.9-14
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• 2004

In this study, Si anisotropic etching characteristics of tetramethylammonium hydroxide (TMAH)/ ammonium persulfate(AP)/isopropyl alcohol(IPA) solutions were investigated to realize the optimum structure of a diaphragm for the piezoresistive pressure sensor application. Due to its low toxicity and its high compatibility with the CMOS processing, TMAH was used as Si anisotropic etchants. The variations of Si etch rate on the etching temperature, TMAH concentration, and etching time were obtained. With increasing the etching temperature and decreasing TMAH concentrations, the Si etch rate is increased while a significant non-unifonnity exists on the etched surface because of formation of hillocks on the (100) surface. The addition of IPA to TMAH solution leads to smoother etched surfaces but, makes the Si etch rate lower. However, with the addition of AP to TMAH solution, the Si etch rate is increased and an improvement in flatness on the etching front is observed. The Si etch rate is also maximized with increasing the number of addition of AP to TMAH solution per one hour. The Si square membranes of 20${\mu}{\textrm}{m}$ thickness and l00-400${\mu}{\textrm}{m}$ one-side length were fabricated successfully by applying optimum Si etching conditions of TMAH/AP solutions.

• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.68-80
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• 2021

Purpose: In this study, potential demographic, social, and economic factors causing tuberculosis were identified, and eight cities in South Chungcheong Province were compared and analyzed with the IPA method. Method: The factors potentially affecting the prevalence of tuberculosis were categorized demographically, socially, and economically, and selected through brainstorming. Furthermore, potential factors affecting tuberculosis were derived using the revised IPA. Based on this analysis, areas with a potential risk of tuberculosis were classified, and the following policy implications were suggested. Result: The analysis found the three cities of Nonsan, Boryeong, and Gongju to have the highest potential risk of tuberculosis, and the frequency of potential risk factors in the above three cities to be 6 or more. Thus, an urgent policy response to prevent tuberculosis in these regions is required. Conclusion: According to the results of this study, it is necessary to take potential risk factors into account when promoting tuberculosis prevention policies and projects in South Chungcheong Province.

• Journal of the Korean Applied Science and Technology
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• v.40 no.4
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• pp.710-723
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• 2023

The purpose of this study is to investigate the effect on the revisit intention and recommendation intention on the golf course selection attribute factors of Chinese golf course users using IPA. In order to carry out this study, a survey was conducted on 388 Chinese golfers, data processing and IPA analysis were conducted, and the following conclusions were obtained. First, the importance of the selection attribute was the highest in employee etiquette, and the price of restaurants and food and beverage was the highest in satisfaction. Second, as a result of the IPA matrix analysis, there were 8 selection attributes for continuous maintenance, 14 for concentration improvement, 5 for low priority, and 3 for excessive effort avoidance. Third, cost, accessibility, course facilities, auxiliary facilities, caddy expertise, and satisfaction with user management were found to affect both revisit and recommendation intentions. Since this study was limited to Chinese golfers, there may be differences in comparing the results with previous studies conducted in other countries on golf culture. Therefore, studies considering cultural diversity should be conducted in the future.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.252-256
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• 2008

We investigated phase separation by adding different concentrations of MTBE, to the mixtures of naphtha, ethanol and water. The phase separation temperatures of the Naphtha-Ethanol-Water solutions have dropped when the concentration of MTBE increases more. When adding IPA and IBA to the solutions of Gasoline-Ethanol and Gasoline base-Ethanol individually, IBA shows lower temperatures of phase separation than IPA, and it shows synergistic effect when mixtures of IPA and IBA is applied.

• The Korean Journal of Applied Statistics
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• v.7 no.2
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• pp.21-34
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• 1994

In this paper we consider the M/M/1 Queue with mean inter arrival time $\theta$. We derive a sample path estimator for the derivative of steady state mean system time with respect to $\theta$. We also show that the derived sample path estimate can be expressed as a sum of the IPA estimate and the other effect. We have a similar result for the derivative of limiting probability $P_k$ with respect to $\theta$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.423-426
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• 1998

Piezoresistive pressure sensors have fabricated using electrochemical etch-stop technique. Si diaphragm having thickness of n-epi. layer was fabricated and used to detect pressure range from 0 to 1 kg/$\textrm{cm}^2$. Piezoresistors were diffused 3${\times}$10$\^$18/ cm$\^$-3/ and placed at diaphragm edge for maximum pressure detection. The characteristics of electrochemical etch-stop in TMAH/lPA/pyrazine solution were also discussed. I-V curves of n and p-type Si in TMAH/lPA/pyrazine solution were obtained. Etching rate is highest at optimum etching condition, TMAH 25wt.%/IPA 17vo1.%/pyrazine 0.1/100m1, thus the elapsed time of etch-stop was reduced.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.127-137
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• 2020

This study is aimed to point out the direction for more reasonable and effective application of future digital technology in the exhibition. It's also to improve the satisfaction of visitors' overall experience through inspecting the special exhibition using digital technology in the national central museum in 2019. The relationship of visitors' expectations, experience and satisfaction are analyzed through literature investigation. Hence, four dimensions of digital experience were summarized on this basis, the content of the questionnaire was set through this research. The satisfaction of visitors to the digital technology experience was evaluated and the key contents needing to be improved were found through Importance-Performance Analysis (IPA). According to the IPA analysis, the content located in quadrant IV is analyzed emphatically, and improvement suggestions are put forward from macro-level, micro-level and viewer's inner levels. The results can be used as a reference for improving the feasibility of the current problem. In order to ensure the forward-looking and timeliness of this field, continuous research will be conducted according to the changes and developments.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.426-433
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• 2023

Capacitor performance was considered using coffee grounds-based activated carbon produced through oil extraction and KOH activation to increase the utilization of boiwaste. Oil extraction from coffee grounds was performed by solvent extraction using n-Hexane and isopropyl alcohol solvents. The AC_CG-Hexane/IPA produced by KOH activation after oil extraction increased the specific surface area by up to 16% and the average pore size by up to 2.54 nm compared to AC_CG produced only by KOH activation without oil extraction. In addition, the pyrrolic/pyridinic N functional group of the prepared activated carbon increased with the extraction of oil from coffee grounds. In the cyclic voltage-current method measurement experiment, the specific capacitance of AC_CG-Hexane/IPA at a voltage scanning speed of 10 mV/s is 133 F/g, which is 33% improved compared to the amorphous capacity of AC_CG (100 F/g). The results show improved electrochemical properties by improving the size and specific surface area of the mesopores of activated carbon by removing components from coffee grounds oil and synergistic effects by increasing electrical conductivity with pyrrolic/pyridinic N functional groups. In this study, the recycling method and application of coffee grounds, a bio-waste, is presented, and it is considered to be one of the efficient methods that can be utilized as an electrode material for high-performance supercapacitors.

• Journal of Information Technology Services
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• v.20 no.4
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• pp.69-80
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• 2021

Many studies have discussed the effectiveness of mentoring from a mentor or mentee perspective. However, it is is necessary to deeply understand the formal mentoring relationship from the perspective of both the mentor and the mentee because the mentoring relationship is the interaction between the mentor and the mentee. Therefore, in this study, the mentors' role through IPA was compared and analyzed from the perspective of mentors and mentees. A survey was conducted on 376 employees of the financial bank, and the managers in charge of the company's official workplace mentoring and employees who participated in the mentoring program were interviewed. As a result of the analysis, mentors are more satisfied with the rewarding experience, while mentees are satisfied with commitment, and organizational ascendency and impact. In addition, mentees judge that "Coach", "Provides support", "Provides vision & widens horizons", "Broaden experience", "Cooperation", "Motivates", "Networking ability", "Provide cross-functional information", "Role model", "Share credit", "Teacher", and "Transfer skills, leadership, & technology" are important as mentor's roles are important. Therefore, in order to foster mentors for effective workplace mentoring, it is necessary to educate the mentor in advance about the mentors' role that the mentee considers to be important.