• Journal of Environmental Science International
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• v.21 no.12
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• pp.1463-1468
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• 2012

The purpose of this work is to study the desorption characteristics of water vapor on zeolites saturated with water vapor. Three kinds of zeolite; zeolite 3A, zeolite 4A, and zeolite 5A were used as adsorbent. The desorption experiments with several different temperatures in the range of $90{\sim}150^{\circ}C$ and several different flow rates in the ranges of 0~0.4 L/min on zeolite bed were carried out. The desorption ability of water vapor was most effective on zeolite 5A among the compared zeolites. The higher the desorption temperature of water vapor was, the faster the desorption velocity was. The desorption ability of water vapor with an air supply was higher than that without an air supply. The most appropriate air flow rate was considered as 0.1 L/min.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.981-989
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• 2024

In recent years, there has been a growing focus on preserving the global environment and utilizing resources efficiently. The significance of energy conservation has led to the development of systems that recycle waste heat from factories and use eco-friendly refrigerants. This study aims to enhance the performance of adsorption-desorption systems using thermoelectric devices, which are known for their ability to convert temperature differences into electrical energy. The research focuses on improving the efficiency of these systems by integrating thermoelectric modules to cool the adsorption side and heat the desorption side, thus enhancing overall system performance. The experiments utilized a typical thermoelectric device and silica gel as the adsorbent. Key experimental parameters included varying the inlet air temperature and relative humidity on the desorption side. The results indicated that increasing the relative humidity of the inlet air on the desorption side significantly enhanced the overall mass transfer coefficient while reducing the completion time of the process. Similarly, higher inlet air temperatures led to an increase in the mass transfer coefficient and a decrease in process completion time. These findings suggest that optimizing the operational conditions of thermoelectric devices can substantially improve the performance of adsorption-desorption systems, offering potential benefits for applications in ventilation systems and other related fields.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.104-118
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• 1995

This study was performed to evaluate factors affecting desorption of organic solvents collected on charcoal tube and to find out the optimum condition. Desorption efficiency for polar analytes was improved when several polar desorption solvents such as methanol, dimethylformamide(DMF), 2-(2-butoxyethoxy)ethanol were added to carbon disulfide($CS_2$). The best improvement was achieved when 10% dimethylformamide(DMF) in $CS_2$ was used as desorption solvent. During storage of polar analytes, recovery was greatly reduced. Especially, the recovery of cyclohexanone was decreased to 18.1 % after a month storage at $34^{\circ}C$. After two weeks storage, recovery of polar analytes was sharply decreased. Water adsorbed on charcoal interfered the recovery of polar analytes but didn't interfere that one of nonpolar solvent, toluene. When 10% DMF in $CS_2$ was used as desorption solvent, the effect of water on recovery was decreased, comparing with Desorption efficiency increased when analyte loading increased, and usage of 10% DMF in $CS_2$ decreased the loading effect. Increasing volume of desorption solvent was not effective to improve desorption efficiency of analytes when 10% DMF was used. Continuous shaking and sonication is not helpful to increase the desorption efficiency of analytes except cyclohexanone using 10% DMF. When silica gel used as adsorbent, methanol was better desorbent than dimethylsulfoxide. Analytes adsorbed on silica gel showed high recovery in low concentration and less affected by humidity. On the basis of this study, the following conclusions have been drawn. To improve the recovery of polar organic materials in air samples, it is necessary to analyze samples as soon as possible after they were collected. Otherwise, samples must be stored at low temperature. Using two components of desorption solvents, such as 10% DMF in $CS_2$, the effects of loading and humidity decreased for polar analytes such as methyl ethyl ketone and methyl isobutyl ketone. When work place has high humidity with low concentration of polar organic solvents, silica gel can be used as adsorbent, because it produces quantitative recovery for polar analytes at this condition. But it should be noted that high humidity makes breakthrough easy in silica gel samples.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.615-623
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• 2014

Increases of public attention on healthy environment lead to the regulation of indoor air quality such as Clean Healthy House Construction Standard. This standard covers emission of total volatile organic compounds (TVOCs) (e.g., formaldehyde, benzene, and toluene), ventilation, and use of environmentally-friendly products or functional products. Moisture absorption and desorption abilities are a recommended functionality for improving indoor air quality. In this study, moisture absorption and desorption capacities of carbonized board from wood-based panels and other materials were determined by using UNT-HEAT-01 according to ISO 24358:2008. Pine had higher moisture absorption and desorption capacities ($49.0g/m^2$ and $35.3g/m^2$, respectively) than hinoki cypress, cement board, gypsum board, oriented strand board, and medium density fiberboard (MDF). The moisture absorption and desorption capacities differed considerably according to the wood species. After carbonization process at $400^{\circ}C$, the absorption and desorption ability of MDF increased to 38% and 60%, respectively. However, moisture absorption and desorption capacities decreased with increasing carbonization temperature, but they were still higher than original MDF. Therefore, it is suggested that carbonization below $600^{\circ}C$ can improve moisture absorption/desorption capacities.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.216-216
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• 2012

The interaction of hydrogen with ZnO single crystal surfaces, ZnO (0001), ZnO (000-1), and ZnO (10-10) has been investigated using temperature programmed desorption (TPD) and X-ray photoelectron Spectroscopy (XPS) techniques. When the ZnO single crystal surfaces are exposed to atomic hydrogen at 200 K, all three surfaces show hydrogen desorption at 450 K. ZnO (0001) surface shows hydrogen desorption feature at ~260 K as the hydrogen exposure is increased. The ZnO (10-10) surface shows low-temperature desorption feature first and the high-temperature desorption feature appears as the hydrogen exposure increases. The ZnO (000-1) surface does not show any lower temperature hydrogen desorption. We will report the adsorption configuration of hydrogen atoms on ZnO single crystal surfaces with different surfaces structures.

• Mass Spectrometry Letters
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• v.7 no.4
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• pp.91-95
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• 2016

In recent years, matrix-free laser desorption ionization (LDI) for mass spectrometry of thermally labile molecules has been an important research subject in the pursuit of new ionization methods to serve as alternatives to the conventional matrix-assisted laser desorption ionization (MALDI) method. While many recent studies have reported successful LDI of thermally labile molecules from various surfaces, mostly from surfaces with nanostructures, understanding of what drives the LDI process still requires further study. This article briefly reviews the thermal aspects involved in the LDI mechanism, which can be characterized as rapid surface heating. The thermal mechanism was supported by observed LDI and postsource decay (PSD) of peptide ions produced from flat surfaces with special thermal properties including amorphous Si (a-Si) and tungsten silicide ($WSi_x$). In addition, the concept of rapid surface heating further suggests a practical strategy for the preparation of LDI sample plates, which allows us to choose various surface materials including crystalline Si (c-Si) and Au tailorable to specific applications.

• Textile Coloration and Finishing
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• v.27 no.3
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• pp.210-218
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• 2015

In this study, natural substance and mineral materials was used for architectural interior wallpaper. Because natural substance and minerals are environment-friendly material with moisture adsorption and desorption properties. Natural substance and mineral materials was evaluated in moisture adsorption and desorption properties. Also, in the diatomite, the pores were observed on SEM photographs. Thus, it is supposed that moisture adsorption and desorption properties were influenced by the microstructure of the pore. The wallpaper according to the ratio of the mixture was analyzed for physical properties and moisture adsorption & desorption properties. As a result, we developed a wallpaper having excellent hygrothermal performance.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.76-81
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• 2009

Thermal desorption systems are designed to remove organic compounds from solid matrices such as soils, sludges and filter cakes without thermally destroying them. It is a separation technology, not a destruction technology. Since it is a thermal process, there is a common belief that temperature is the only significant parameter to be monitored. While it is true that better removal efficiencies are usually achieved at higher temperatures, other factors must be considered. Since the process is governed by mass transfer, heating time and the amount of mixing are also key parameters in optimizing removal efficiency. Thermal desorption have been successfully used for just about every organic contaminant found to date. It has also been used to remove mercury. In the present study, the numerical simulation has been performed to investigate the characteristics of heat transfer of LTTD(low temperature thermal desorption). The commercial software, AMESIM was applied for analyzing the heat transfer process in the LTTD.

• Journal of Power System Engineering
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• v.17 no.1
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• pp.71-76
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• 2013

This study is experimentally performed for using the oyster shell as a desiccant in the batch type system. The peltier element(thermoelectric device) is used for absorbing and releasing the adsorption and desorption heat generation. The cooling and heating effects of peltier element exist in this experiment and these effects are generally known phenomena among some references. The increase in electric current induced into peltier element is effectively release the heat generation of adsorption and desorption. Consequently, the non-dimensional adsorption and desorption amount would increase with increase in electric current. However, in the case of adsorption, the increase of induced current into peltier element, the heat of cold side can not release sufficiently. So the heat of hot side of peltier is transferred into the cold side.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.21-29
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• 2008

Sorption and desorption processes play an important role in the transport and fate of organic contaminants in subsurface system. In this study, sorption and desorption characteristics of atrazine in 7 soils selected at the Gwangju area were investigated. Soil organic carbon contents ranged from 0.42 to 2.82%. Sorption and desorption experiments were performed in batch slurries. Sorption distribution coefficient ($K_d$) of atrazine were ranged from 0.48 to 3.26 l/kg and $K_d$ value increased with increasing organic carbon contents except of Kyongbang and Youngdong soils. Single desorption data were analyzed by the three-site desorption model including equilibrium, non-equilibrium and non-desorbable site. Non-desorbable site fractions of atrazine in all soils were enumerated and non-desorbable atrazine was observed in seriesdilution desorption experiment. Sorption/desorption hysteresis was also observed in the series-dilution desorption experiment.