• Macromolecular Research
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• v.11 no.5
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• pp.387-392
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• 2003

The ablation effects of Ar-plasma treatment and alkali-decomposition behavior in NaOH solution of polyethylene terephthalate (PET) film were investigated. The modifications were evaluated by analysis of atomic force microscopy topographical changes, and by the measurement of decomposition yield in conjunction with heats of formation and electron densities of acyl carbon calculated by Parameterization Method 3 method. It has shown that the alkali-decomposition is hampered by plasma treatment and its decomposition yield is closely related with plasma treatment conditions such as exposure time to plasma. Plasma-treated PET films exhibited lower decomposition yield, compared to that of virgin PET. Increasing plasma exposure time contributes positively to decrease the decomposition yield. It has also shown that the topography of PET surface was affected by the base-promoted hydrolysis as well as Ar-plasma treatments. These behaviors are attributed to the decreased nucleophilicity of acyl carbon damaged by the ablation of Ar-plasma.

• Textile Coloration and Finishing
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• v.14 no.4
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• pp.214-222
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• 2002

In order to give a silk-like touch to PET fabrics, the PET fabrics were treated with NaOH alkaline solution in various conditions. In alkaline treatment, the liquor flow type pilot weight reduction apparatus with magnetostrictive ultrasonic transducer was used for the study. The weight loss of PET fabrics hydrolyzed in 4% and 6% NaOH solution, at $95^\circ{C}$ and $99^\circ{C}$ for 60min. with ultrasonic application showed 3.7~4.6% higher than that of treated fabric without ultrasonic application. From the difference of specific weight loss, the treatment condition of the maximum of hydrolyzation effect appeared at $95^\circ{C}$ in $4^\circ{C}$ and at $90^\circ{C}$ in 6% NaOH solution, respectively. During the alkali hydrolysis of PET fabrics, the decomposition rate constant(k) increased exponentially with the treatment temperature and were not related with ultrasonic cavitation. The activation energy$(E_a)$ in decomposition of PET fabrics were 21.06kcal/mol with ultrasonic application and 21.10kcal/mol without ultrasonic application. The ultrasonic application gave a little higher value of the activation entropy$(\Delta{S}^\neq)$ and a little lower value of Gibbs free energy$(\Delta{S}^\neq)$ compared with not used ultrasonic apparatus.

• Journal of The Korean Digital Architecture Interior Association
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• v.12 no.4
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• pp.59-66
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• 2012

This study is interested in identifying the effectiveness of alkali-activated fire protection material compounds including the alkali-activator such as potassium hydroxide, sodium silicate and fly ash as the fire resistant finishing materials. Also, this paper is concerned with change in compressive strength and pore structure of the alkali-activated fire protection material at high temperatures. The testing methods of fire protection materials in high temperature properties are make use of TG-DSC and mercury intrusion porosimetry measurements. This study results show that compressive strength is rapidly degraded depending on a rise of heating temperature. Porosity showed a tendency to increase irrespective of specimen types. This is due to both the outbreak of collapse of gel comprising the cement and a micro crack by heating. However, alkali-activated fire protection material composed of potassium hydroxide, sodium silicate and fly ash has the thermal stability of the slight decrease of compressive strength and porosity at high temperature. These thermal stability is caused by the ceramic binding capacity induced by alkali activation reaction by the reason of the thermal analysis result not showing the decomposition of calcium hydrate.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2867-2872
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• 2010

Two new energetic organic alkali metal salts, 1,1-diamino-2,2-dinitroethylene rubidium salt [Rb(FOX-7)${\cdot}H_2O$] and 1,1-diamino-2,2-dinitroethylene cesium salt [Cs(FOX-7)${\cdot}H_2O$], were synthesized by reacting of 1,1-diamino-2,2-dinitroethylene (FOX-7) and rubidium chloride or cesium chloride in alkali methanol aqueous solution, respectively. The thermal behaviors of Rb(FOX-7)${\cdot}H_2O$ and Cs(FOX-7)${\cdot}H_2O$ were studied with DSC and TG methods. The critical temperatures of thermal explosion of the two compounds are 216.22 and $223.73^{\circ}C$, respectively. Specific heat capacities of the two compounds were determined with a micro-DSC method, and the molar heat capacities are 217.46 and $199.47\;J\;mol^{-1}\;K^{-1}$ at 298.15 K, respectively. The adiabatic times-to-explosion were also calculated to be a certain value of 5.81 - 6.36 s for Rb(FOX-7)${\cdot}H_2O$, and 9.92 - 10.54 s for Cs(FOX-7)${\cdot}H_2O$. After FOX-7 becoming alkali metal salts, thermal decomposition temperatures of the compounds heighten with the rise of element period, but thermal decomposition processes become intense.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.718-722
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• 2017

We have investigated the photocatalytic activity for the decomposition of methyl orange on the pure $LaCoO_3$ and metal ion doped $LaCoO_3$ perovskite-typeoxides prepared using microwave process. In the case of pure $LaCoO_3$ and cesium ion doped $LaCoO_3$ catalysts, the formation of the perovskite crystalline phase was confirmed regardless of the preparation method. From the results of UV-Vis DRS, the pure $LaCoO_3$ and cesium ion doped $LaCoO_3$ catalysts have the similar absorption spectrum up to visible region. The chemisorbed oxygen plays an important role on the photocatalytic decomposition of methyl orange and the higher the contents of chemisorbed oxygen, the better performance of photocatalyst.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.1
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• pp.31-37
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• 1993

To analyze and classify the varietal variation of alkali digestibility in detail, which is closely connected with the gelatinization temperature and physical characteristics of cooked rice, the patterns of alkali decomposition changed along the alkali concentration were investigated for thirty three Korean leading rice cultivars and new breeding lines(japonica : 25, Tongil-type:8) including five glutinous rice. Principal component analysis was used to condense the information and to classify rice materials according to decomposed reaction pattern at several levels of potassium hydroxide(KOH) concentration. Thirty three rice varieties were classified largely into four groups by the distribution on the plane of upper two principal component scores which contained above 92% of total informations. Group I was consisted of one variety, Dobongbyeo, which owned almost same strong resistance to alkali digestion at the range of 0.8% to 1.6% KOH solutions. Group II included three japonica and Tongil-type glutinous rice varieties, which revealed medium alkali digestion value(ADV) at 1.4% KOH solution and intermediate change in ADV from 0.8% to 1.6% KOH solutions. Most of Tongil-type and early-maturity japonica rice, which exhibited medium-high ADV at 1.4% of KOH concentration and large ADV difference between low and high alkali solutions, were contained in Group III. Group N included most of medium or medium-late-maturity japonica, which showed high ADV at 1.4% KOH and medium or intermediate-high ADV change between low and high alkali solutions. The 1st principal component indicated the average index of ADV through 0.8-1.6% KOH solutions and the 2nd principal component pointed out the factor related with ADV difference between low and high alkali solutions or regression coefficients of ADV change along with the KOH concentrations.

• Asian Journal of Atmospheric Environment
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• v.10 no.4
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• pp.190-196
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• 2016

The objective of this study is to obtain the optimal conditions to remove hydrogen fluoride (HF) generated from a variety of F-gas treatment processes. First, we selected $Ca(OH)_2$ and $CaCO_3$ as a reactant among the various alkali salts which have a high removal efficiency and a competitive price by forming a calcium fluoride precipitate. Additionally, various factors were investigated to improve the removal efficiency of HF. The conditions such as the settling time, agitating time and intensity, reaction temperature, and pH were considered as main factors. As a result, in the treatment process to remove HF through Ca-based alkali salts, the optimal conditions were a 120 min settling time, 30 min of agitation at 100 rpm, a pH of 4-8, and a reaction temperature of $40^{\circ}C$.

• Journal of the Korean Society of Safety
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• v.4 no.1
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• pp.75-81
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• 1989

The aim of this study is, by the Lime-Stabilization of decayed Organic Wastes, in preventing the reclaimed Waste from being another pollution due to reclaiming those things. 1. A perfect reaction is possible by the addition of poor Stabilization-Lime of 5 percent in a short time of 5 minute. 2. PH of the Stabilization-handled Wastes rise over 12. 3. Malodorant of Stabilized Wastes is slight because malodorant Volatilize in the course of the Stabilization or is captured in the handled subetance. 4. The second pollution scarcely brings about because a rapid decomposition is impossible on account of the coating of Alkali Substance.

• Textile Coloration and Finishing
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• v.14 no.6
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• pp.305-312
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• 2002

In order to give a silk-like touch to PET fabrics, the PET fabrics were treated with NaOH alkaline solution in various conditions. In alkaline treatment, the liquor flow type pilot weight reduction apparatus with magnetostrictive ultrasonic transducer was used for the study. The effects of ultrasonic application, treatment time and temperature at NaOH 4% and 6"A solution on the decomposition rate of PET fabrics. From the results of the decomposition rate of PET fabrics, the qualitative and quantitative analysis of oligomer after decomposition of PET fabrics carried out by the HPLC. On the other hand, the surface pore characteristics of decomposition PET fabrics measured by porosimetery. The pore characteristics on the surface of treated PET fiber depended on the decomposition rate and did not depend on the ultrasonic cavitation. The pore diameter of alkaline untreated PET fiber were 15A and those of treated PET fibers were 5~6$\AA$ at the maximum pore volume. The average pore sizes of fiber before and after treatment were 141 h and 160h, respectively. Total amount of oligomer of the untreated PET fibers were 1.70wt% and 67.7% of total oligomer occupied with PET cyclic trimer and PET cyclic tetramer. Total amount of oligomer of fiber with 26.9% and 48.0% of weight loss without ultrasonic application were 1.78wt% and 1.79wt%, respectively. Also total amount oligomer of fibers which were reduced 27.7% and 48.2% of weight loss with ultrasonic application were 1.74wt%. This result showed that the removal rate of oligomer in the process of alkaline hydrolysis with ultrasonic higher than that of without ultrasonic application.tion.

• The Journal of the Petrological Society of Korea
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• v.3 no.1
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• pp.41-48
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• 1994

Three USGS rock standards (G-2, W-2, and BHVO-1) are decomposed by three different methods, such as open beaker, microwave oven, and alkali fusion method, to compare the effect of decomposition methods for trace elememt analysis in the rock samples. Solubilized trace elements are measured with inductively coupled plasma mass spectrometer (ICP-MS). Generally the analytical results of trace elements between open beaker and microwave digestion method are not different. In case of alkali fusion method, some volatile elements such as Pb, Cu, and Rb are considerably lost. Using acid digestion method, Zr and Hf concentrations are lowered in case that these elements are concentrated in refractory minerals. The concentrations of rare earth elements are generally consistent with the recommended values, but due to large dilution factor, there are some analytical problems in alkali fusion method.