• Korean Chemical Engineering Research
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• 제54권4호
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• pp.548-554
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• 2016

Damascene 구조를 갖는 반도체소자의 구리금속배선 식각공정에서 배선재료에 의해서 발생되는 구리 식각잔류물을 제거하기 위해 oxalic acid (OA), lactic acid (LA) 및 citric acid (CA)의 카르복시산 함유된 반수계 혼합세정액을 제조하고 특성을 분석하였다. 카르복시산은 pH에 따라 카르복실기와 구리이온들과의 다양한 복합체를 형성하며 세정특성의 변화를 준다. 카르복시산들이 함유된 각각의 세정액의 세정특성평가결과 10 wt% CA를 함유한 반수계 세정액의 식각잔류물 세정특성은 pH 2에서 7까지의 영역에서 가장 낮은 구리 식각률을 보였으며 pH 2에서 4까지 구리에 대한 구리산화물의 가장 높은 식각 선택도를 나타내었으나 pH 5에서 7 범위에서는 10 wt% LA가 함유된 세정액이 더 높은 선택도를 보였다. 따라서 표면세정효과는 pH에 따라 변화하며 적절한 카르복시산을 사용함이 요구된다. CA가 함유된 세정액의 경우에 CA 농도와 구리에 대한 구리산화물의 식각 선택도의 증가특성을 보이며 CA가 5 wt%이상 함유된 경우에는 세정 후 구리배선의 표면이 88 %이상의 금속구리로 분석되어 구리산화물로 구성된 식각 잔류물의 제거에 효과적임을 알 수 있었다.

• The Journal of Korean Physical Therapy
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• 제22권2호
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• pp.31-38
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• 2010

Purpose: We investigated the relationship of depression and the ability to engage in activities of daily living in the elderly. Methods: Subjects (n = 182) were 60 years or older and who attended the Senior College of Gimhae Senior Welfare Center. We collected data via a questionnaire, through a Self- recording method and through individual interviews. We collected data on personal and general characteristics, level of depression, and activities of daily living. Results: Among all subjects, 51.1% reported having depressionMild depression was reported by 29.7% (54 subjects), moderate depression by 13.2% (24 subjects), and severe depression by 8.2% (15 subjects). Activities of daily living, including walking, climbing stairs, standing from a chair and sitting on and using toilets, using a telephone, bathing, shopping, cleaning house, and managing money were significantly lower in elderly subjects who were depressed (p<0.05). The greater the level of depression, the less able they were to engage in activities of daily living. Conclusion: These findings may help us achieve early detection of depression in the elderly and provide mediated arbitration so that they can have better health condition and greater ability to engage in activities of daily living.

• 한국염색가공학회지
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• 제25권3호
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• pp.194-205
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• 2013

In this study, we report dyeing properties and functionality of cotton and silk fabrics dyed with methanol extract from Juniperus chinensis heartwood. Non-aqueous dye of Juniperus chinensis heartwood extracted with methanol was expressed reddish color. It showed relatively good affinity to silk than cotton. Dye uptake of cotton and silk continued to increase according to the increase of the dye concentration. Cotton was not affected by the dyeing temperature and time, however, dye uptake of silk was increased as the dyeing time and temperature were increased. Dye uptake of cotton and silk were the highest at pH 8 and pH 6 respectively. Dyed fabrics showed various colors depending on mordant types and mordant concentration. Washing, light and perspiration fastness were not good. However, rubbing and dry cleaning fastness showed relatively good grade. Dyed fabrics of ultraviolet-cut ability and deodorant ability were improved. Also, dyed fabrics showed very good antimicrobial abilities of 99.9%.

• 한국염색가공학회지
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• 제25권3호
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• pp.181-193
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• 2013

The purpose of this study is to investigate dyeing properties and functionality of cotton and silk fabrics dyed with hot-water extract from Juniperus chinensis heartwood. Water-soluble dye of Juniperus chinensis heartwood extracted with distilled water was expressed YR color series. Dye uptake of cotton continued to increase according to the increase of the dye concentration. Its variation trends were shown to be similar to the isothermal absorption curve of the Freundlich. Dye uptake of silk was better than cotton, increased depending on increasing concentration of the dye, dyeing time and temperature. Its variation trends were shown to be similar to the isothermal absorption curve of the Langmuir. As the pH increased, the dye uptake of fabrics reduced and showed increased on red tinge. Colors of the dyed fabrics were various, depending on dye concentration and the mordant type and mordant concentration. Washing fastness, light fastness and perspiration fastness were not good. However, rubbing and dry cleaning fastness showed relatively good grade. Dyed fabrics of ultraviolet-cut ability and deodorant ability were improved. And dyed fabrics showed antimicrobial abilities of 99.9% against Staphylococcus aureus.

• Structural Engineering and Mechanics
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• 제86권1호
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• pp.109-118
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• 2023

Any place where exercise is common, such as a club, sports hall, or school, is considered a place for teaching sports. When doing sports, a very safe environment for sports should be chosen. The athlete should consider the safety of sports facilities and equipment, and if there is a defect, he should refrain from exercising in these places. The safety of sports facilities is very effective in creating people's sports activities, with the benefits of staying away from physical harm, enjoying sports, and having mental peace. Everyone has the right to participate in sports and recreation and to ensure that they enjoy a safe environment. The ability to manage and solve issues that may arise plays the most critical role in creating a safe environment. The quality of construction materials used for the construction of sports facilities is of great importance. In this work, the resistance and water repellency of concrete constituents for the construction of sports buildings have been investigated by nanoscience. Nano-concrete material solves the main problem of concrete surfaces, i.e., the entry of water and humidity into the structure. It also gives it a self-cleaning ability with its water repellency. Nanoparticles are placed between pores and cover the cracks, which causes roughness in the surface structure of concrete. The high roughness of the surface of the coated concrete caused its super-hydrophobicity. In hydrophobic surfaces, the higher the contact angle, the more hydrophobic the surface will be. In order to investigate the hydrophobic properties, silica nanoparticles, silica nanoparticles, and fly ash were prepared on concrete, and their properties were analyzed.

• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.139-147
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• 2019

Incorporation of CuO nanoparticles during the polymerization of aniline in the presence of ammonium peroxydisulphate as an oxidizing agent and sodium salt of dodecylbenzene sulphonic acid as dopant as well as surfactant yielded water soluble CuO-PANI composite. Comparison of recorded spectra like FTIR, XRD and SEM with reported one confirm the formation of the composite. Analysis by gravimetric method exposes that the synthesized composite is having resistivity against corrosion, with slight variation in efficiency on extending the time duration up to eight hours in strong acidic condition. OCP measurement, potentiodynamic polarization and EIS studies also confirms the suppression ability of composite against corrosion. Riskless working environment could be provided by the synthesized composite during industrial cleaning process.

• 한국환경과학회지
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• 제14권10호
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• pp.979-983
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• 2005

Indoor air quality has been addressed as an important atmospheric environmental issue and has caught attention of the public in recent years in Korea. Good indoor air quality in classrooms favour student's learning ability, teacher and staff's productivity according to other studies. In this study, each classroom at four different schools was chosen for comparison of indoor and outdoor air quality by means of source generation types such as new constructed classroom, using of cleaning agents and purchased furniture. Temperature, relative humidity (RH), carbon dioxide $(CO_2)$, formaldehyde (HCHO), total volatile organic compounds (TVOCs) and particulate matter with diameter less than $10{\mu}m\;(PM_{10})$ were monitored at indoor and outdoor locations during lesson. HCHO was found to be the worst among parameters measured in new constructed classroom, HCHO and TVOCs was worst in classroom with new purchased furniture, and TVOCs was worst in classroom cleaned by cleaning agents, Indoor $(CO_2)$ concentrations often exceeded 1500 ppm indicating importance of ventilation. Active activity of students during break time made the $PM_{10}$ concentration higher than a lesson, Improvements and further researches should be carried out considering indoor air quality at schools is of special concern since children and students are susceptible to poor air quality.

• 한국염색가공학회지
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• 제18권2호
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• pp.8-14
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• 2006

The pigment extraction of Opuntia ficus-indica has been conducted to develop useful natural dyes in place of synthetic dyes which are suspected to bring serious environmental pollutions. The dyeing ability on wool fabric by addition of ascorbic acid and several mordants were investigated by means of color measurement. In addition, the fastness of washing, perspiration, rubbing, light, dry cleaning, effect on bacterial reduction and UV-B protection were also investigated. From these investigation, it is suggested that the pigment extracted from Opuntia ficus-indica can be used as a source of natural dyes and the obtained result are as follows. 1. Maximum absorption band (${\lambda}max$) of Opuntia ficus-indica extract is 533nm. 2. The wool fabric dyed with Opuntia ficus-indica extract has stable color by the addition of ascorbic acid and is achieved with addition of 0.1% ascorbic acid, 0.5% several mordant, and three repeated dying at $50^{\circ}C$ for 1.5hr. 3. The wash fastness of the dyed wool fabric when it is washed with neutral detergent is more effective than alkaline detergent. The dry cleaning fastness of the dyed wool fabric is more excellent. In addition, the perspiration fastness of the dyed wool fabric is increased by mordanting method. And than the rubbing fastness of the dyed wool fabric is showed excellent under dryness and wetness. Light fastness of the dyed wool fabric, however is showed inferiority. 4. The wool fabric dyed with Opuntia ficus-indica extract is showed effective bacterial reduction and UV-B protection is increased remarkably.

• 전력전자학회논문지
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• 제14권1호
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• pp.72-81
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• 2009

본 논문에서는 대기압 플라즈마 발생용 정현파펄스형 교류 전원 장치에 대한 연구를 진행하였다. 정현파펄스형 전원장치는 기존의 LC공진을 이용한 교류 전원장치보다 높은 dv/dt를 갖게 되므로 안정적인 플라즈마 공급이 가능하며 펄스형에 비해 고조파 노이즈가 적고, 정전류 턴온-영전압 턴오프 형태로 동작하므로 매우 높은 효율을 갖는다. 또한 플라즈마 점화 기능을 강화하고 안정적인 전압제어를 위해 3상 부스트형 컨버터를 입력단에 사용하여 입력 역률이 매우 높은 시스템을 구성할 수 있다. 실험실 수준의 10kW부하시설을 사용하여 본 연구의 결과를 입증하였다.

• 한국표면공학회지
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• 제34권1호
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• pp.62-67
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• 2001

Green technology is being developed up to a point that is feasible not only in an environmental sense, but also in an economical viewpoint. This paper introduces two case studies that applied $CO_2$ technology into nuclear industry. 1) Nuclear laundry : A laundry machine that uses liquid and supercritical $CO_2$ as a solvent for decontamination of contaminated working dresses in nuclear power plants was developed. The machine consists of a 16 liter reactor, a recovery system with compressors, and storage tanks. All $CO_2$ used in cleaning is fully recovered and reused in next cleaning, resulting in no production of secondary nuclear waste. Decontamination factor is still lower than that in the methods currently used in the plant. Nuclear laundry using $CO_2$ looks promising with technical improvements-surfactants and mechanical agitation. 2) $CO_2$ nozzle decontamination : An adjustable nozzle for controlling the size of dry ice snow was developed. Using the developed nozzle, a surface decontamination device was made. Human oils like fingerprints on glass were easy to remove. Decontamination ability was tested using a contaminated pump-housing surface. About 40 to 80% of radioactivity was removed. This device is effective in surface-decontamination of any electrical devices like detector, controllers which cannot be cleaned in aqueous solution.