• Journal of Integrative Natural Science
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• v.3 no.2
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• pp.96-102
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• 2010

It is still controversial where the improved stability of n-octadecyltriethoxysilane self-assembled monolayer (OTE SAM) on plasma-pretreated mica surface exactly originates from. To date, it has been well known that the extensive cross-polymerization between silane headgroups is a crucial factor for the outstanding mechanical strength of the monolayer. However, this study directly observed that the stability comes not only from the cross-links but also, far more importantly, from the direct chemical bonds between silane headgroups and mica surface. To observe this phenomenon, n-octadecyltrichlorosilane monolayers were self-assembled on both untreated and plasma treated mica surfaces, and their adhesion properties at various stress conditions and force profiles in pure water were investigated and compared through the use of the surface forces apparatus technique. It revealed that, in pure water, there is a substantial difference of stability between untreated and plasma treated cases and the plasma treated surface is mechanically much more stable. In particular, the protrusion behavior of the monolayer during contact repetition experiment was always observed in the untreated case, but never in the plasma treated case. It directly demonstrates that the extensive chemical bonds indeed exist between silane head-groups and plasma treated mica surface and dramatically improve the mechanical stability of the OTE monolayer-coated mica substrate.

• Korean Journal of Veterinary Service
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• v.45 no.4
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• pp.277-284
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• 2022

Salmonella is a pathogenic bacterium that has long been important industrially because it has a wide host range and can be transmitted to humans through direct contact as well as indirect contact such as food contaminated with animal waste. Understanding how to reduce Salmonella contamination in pig farms is important for public health and the livestock industry from an economic perspective. In the swine industry, high concentrations of disinfectants have been applied because it is difficult to effectively control Salmonella in environments contaminated with organic substances. In order to evaluate the synergetic effect of disinfectants, the efficacy of two commercial disinfectants diluted in hard water and microbubble water (MBW) were compared under the laboratory condition. Different concentrations of both disinfectants combined with 1% detergent diluted in the two diluents were evaluated for their antibacterial effect. In the case of monopersulfate-based disinfectant groups, the growth of Salmonella was not observed at 1:200 dilution with both the hard water and MBW combined with 1% detergent. In the case of citric acid-based disinfectant, the bacterial growth was not observed at 1:800 dilution with MBW combined with 1% detergent. Our results show that the use of MBW as a diluent might improve the biological activities of acid-based disinfectant.

• Journal of Power System Engineering
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• v.9 no.2
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• pp.88-92
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• 2005

The experiment of thermal performance about closed-wet cooling tower was conducted in this study. A closed cooling tower is a device similar to a general cooling tower, but with cooling tower replaced by a heat exchanger. The test section for this experiment has the process that the cooling water flows from the top of the heat exchanger to the bottom side in the inner part of the tube, and spray water flows in the gravitational direction in the outer side. Air comes in direct contact with the spray water at the outer side of the tube while passing from the lower the upper part having a counterflow to the spray water. The heat transfer pipe used in this experiment is a bare-type tube having an outer diameter of 15.88mm. The heat exchanger is consisted of seven rows and fifteen columns. In this experiment, thermal performance of the cooling tower is derived from overall heat transfer coefficients between the process fluid and sprayed water and volumetric overall mass transfer coefficient between sprayed water and air.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.172.1-172.1
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• 2010

In Jeju, underground air is used for heating greenhouse and fertilizing natural $CO_2$ gas by suppling directly into greenhouse. But greenhouse heating method by direct supply of underground air has several problems as like low temperature below $20^{\circ}C$ or high relative humidity over 90%. The underground air is inadequate in heating of crops such as mangos, oranges with the growing temperature over $20^{\circ}C$. Also if the relative humidity of greenhouse is kept with over 90%, diseases can strike almost of the crops. And also the ventilation loss becomes larger because the air pressure of inside greenhouse by direct supply of underground air is higher. In this study the heat pump system using underground air as heat source was developed and heating performance of the system was analyzed. Heating COP of the system was 2.5~5.0 and rejecting heat into greenhouse and extracting heat from underground air in this heat pump system were 46.5~31.4 kW, 34.9~20.9 kW respectively.

• Journal of Biosystems Engineering
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• v.37 no.3
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• pp.209-213
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• 2012

Purpose: This study was performed to develop a simple, disposable thin-film optical nitrate sensor. Methods: The sensor was fabricated by applying a nitrate-selective polymer membrane on the surface of a thin polyester film. The membrane was composed of polyvinylchloride (PVC), plasticizer, fluorescent dye, and nitrate-selective ionophore. Fluorescence intensity of the sensor increased on contact with a nitrate solution. The fluorescence response of the optical nitrate sensor was measured with a commercial fluorospectrometer. Results: The optical sensor exhibited linear response over four concentration decades. Conclusions: Nitrate ion concentrations in plant nutrient solutions can be determined by direct optical measurements without any conditioning before measurements.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.1
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• pp.15-23
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• 2016

Gelatin soft capsules, manufactured by the press through package(PTP) process, are widely used in the production of multivitamin dietary supplements and other health functional foods. Gelatin capsules can prevent light and air from having a direct contact with the contents in the capsule, and the nutrients inside the capsules are preserved without any loss. In the present study, on the basis of the results on the safety of gelatin capsules. The parameters investigated included degradation of the capsules before their shelf life, capsule deformation, and changes in specific nutrients. Moisture and heat in the production and storage environments of the capsules caused the gelatin to swell and attach some of the inorganic salts in the vitamin contents. Nutritional component analysis showed that B1, B5, B9, and B12 contents were decreased, while mineral elemental analysis shown calcium, chloride, and zinc compound were found to be infused into the gelatin of the capsule shell.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.107-107
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• 1999

Direct-contact condensation experiments of atmospheric steam and steam/air mixture on subcooled water flowing co-currently in a rectangular channel are carried out uszng an infrared thermal camera system to develop a temperature measurement method. The inframetrics Model 760 Infrared Thermal Imaging Radiometer is used for the measurement of the temperature field of the water film for various flow conditions. The local heat transfer coefficient is calculated using the bulk temperature gradient along the (low direction. It is also found that the temperature profiles can be used to understand the interfacial condensation heat transfer characteristics according to the flow conditions such as noncondensable gas effects, inclination effect, and flow rates.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.442-447
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• 2006

In semiconductor manufacturing clean rooms, it becomes important to remove airborne molecular contaminants as well as particulate contaminant in outdoor air introduced into clean rooms. One suitable control technique for these chemical contaminants is air washing by water in an outdoor air handling unit. In order to enhance the removal efficiency of chemical contaminants the effect of adding a heating and humidifying process before an air washer was examined.

• Korean Journal of Materials Research
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• v.8 no.12
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• pp.1138-1145
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• 1998

The sliding wear behavior of Ni-base hardfacing alloy, Deloro 50, was investigated at the contact stresses of 15ksi and 30ksi under the various wear environments. In air at room temperature, Deloro 50 showed lower wear resistance than Stellite 6 even at 15ksi due to the occurrence of severe adhesive wear. This seems to be caused by the lower hardness and work- hardening rate of Deloro 50 than those of Stellite 6. In water at room temperature, Deloro 50 showed as good wear resistance as Stellite 6 at 15ksi. It was considered to be due to that water could effectively prevent metal to metal contact through contacting asperities. However, Deloro 50 showed severe adhesive wear at 30ksi in water at room temperature. It seems to be that the water could not suppress adhesion wear at 30ksi. At $300^{\circ}C$ in air, Deloro 50 exhibited higher wear resistance than Stellite 6 even at 30ksi. It was considered that the oxide glaze layers formed on wear surface during sliding, effectively prevented direct metal-to-metal contacts.

• Journal of Korean Academy of Nursing Administration
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• v.2 no.2
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• pp.5-16
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• 1996

The purpose of this study is to identify the handwashing knowledge and attitudes of resistered nurses on general wards. Subjects for this study include 182 nurses working in general wards of a hospital in Seoul area. Data were collected by a questionnaire from July 30 to August 10,1996. Statistical analyses were done by the SPSS/PC program. The techniques used in this sudy included frequencies, chi-square test. The results of this study are summarized as follows. 1. 34.6% of the respondents reported that they washed their hand an average of 5 to 7 times during the work day. 2. 38.5% of the respondents reported always washing after each patient contact. Only 9.9% always washed before contact with a patient. 3. 56.6% of the respondents reported a washing time of 10 to 20 seconds, whereas 29.1% washed 21 to 30 seconds. Chi-square tests were employed to determine any differences in handwashing frequency and duration by age, working years, work position. There were no satistically significant differences among the variables. 4. 95.6% of the subjects used water and plain soap during the washing process. The respondents washed the palms of the hands, the backs of their hands and between their fingers(33%). Only 17.6% removed rings before handwashing. Similarly, 11% removed their wristwatch. The majority(96.2%) reported that they used communal textile towel to dry their hands. When asked what method they used to turn off the water faucet after washing, 98.4% reported using direct hand-to-faucet contact. 5. Nursing activities that showed the highest handwashing rates was after wound dressing(22.9%), followed by suctioning(21.4%), injection(21.2%), inserting catheter(18%). 6. Reasons cited for reduced handwashing frequency included being too busy to wash more often(74.7%), no need to wash more often(11.0%) and dry skin caused by frequent handwashing(3.3%). 7. When asked where they obtained their current knowledge of handwashing techniques, they reported professors(73.6%), resisted nurses(14.8%) and supervisor(6.6%). 8. Nursing staff thought that proper handwashing was important factor in decreasing nosocomical infections(72.4%).