• Membrane Journal
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• v.25 no.4
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• pp.310-319
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• 2015

Three kinds of anion-exchangeable functional groups with different hydrocarbon molecular structures were introduced to vinyl benzyl chloride-based membrane to understand the effect of attached function in anion-exchange membrane. Trimethylamine (TMA) as an aliphatic fuction, N-methylpiperidine (MP) as an alicyclic fuction and pyridine (Py) as an aromatic function were introduced by amination. The respective reactivity was observed by the trace of membrane resistance( MER)/ion exchange capacity (IEC) and the increasing order of reactivity was Py < MP < TMA. Meanwhile, SEM photograph showed the attached Py ion-exchange membrane was the most homogenous and compact structure in the study. In electrochemical properties, the attached Py ion-exchange membrane showed the MER ($5.0{\Omega}{\cdot}cm^2$ >, in 0.5 mol/L NaCl), comparable to those of commercial membrane (AMX). All results showed that the resonance structure of attached functional group might contribute to the preparation of homogenous anion-exchange membrane.

• Korean journal of food and cookery science
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• v.21 no.5
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• pp.662-668
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• 2005

To investigate the quality retention method of salted and semi-dried mackerel fillets, pH, volatile basic nitrogen (VBN), trimethylamine (TMA) and total bacterial counts in the fillets that were UV treated for 1, 3, and 4 hr were periodically measured during 48 days of refrigerated storage. The moisture, crude protein, crude lipid, and ash contents were 45.46 %, 18.87 %, 33.75 %, and 2.99 %, respectively. The freshness as determined by pH measurement could be maintained up to 25 days for the control and 31 days for the UV-treated fillets. VBN contents were continually increased over the storage time. The control reached the initial putrid level after 21 days while the UV-treated fillets after $25{\sim}31$ days. A similar tendency was shown for the changes of trimethylamine TMA contents, although the period differed slightly and the increase of the UV treatment time could decrease the TMA contents. The changes on the total bacterial counts of the fillets were maintained under 105 CFU/g during 48days. Especially, due to the effective decrease of the microorganism count by UV treatment at the beginning of the storage, UV -treated fillets showed lower bacterial counts than control over the whole period. E. coli. and Listeria were not detected in any fillets. Combining the above data and the sensory changes, the storage period of the fillets could be prolonged from 15 days at present to 30 days by UV treatments.

• Physical Therapy Korea
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• v.21 no.3
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• pp.80-88
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• 2014

Previous studies have reported that decreased cognitive ability has been consistently associated with significant declines in performance of one or both tasks under a dual-task walking condition. This study examined the relationship between specific cognitive abilities and the dual-task costs (DTCs) of spatio-temporal gait parameters in stroke patients. The spatio-temporal gait parameters were measured among 30 stroke patients while walking with and without a cognitive task (Stroop Word-Color Task) at the study participant's preferred walking speed. Cognitive abilities were measured using Computerized Neuropsychological Testing. Pearson's correlation coefficients (r) were calculated to quantify the associations between the neuropsychological measures and the DTCs in the spatio-temporal gait parameters. Moderate to strong correlations were found between the Auditory Continuous Performance test (ACPT) and the DTCs of the Single Support Time of Non-paretic (r=.37), the Trail Making A (TMA) test and the DTCs of Velocity (r=.71), TMA test and the DTCs of the Step Length of Paretic (r=.37), TMA test and the DTCs of the Step Length Non-paretic (r=.36), the Trail Making B (TMB) test and the DTCs of Velocity (r=.70), the Stroop Word-Color test and the DTCs of Velocity (r=-.40), Visual-span Backward (V-span B) test and the DTCs of Velocity (r=-.41), V-span B test and the DTCs of the Double Support Time of Non-paretic (r=.38), Digit-span Forward test and the DTCs of the Step Time of Non-paretic (r=-.39), and Digit-span Backward test and the DTCs of the Single Support Time of Paretic (r=.36). Especially TMA test and TMB test were found to be more strongly correlated to the DTCs of gait velocity than the other correlations. Understanding these cognitive features will provide guidance for identifying dual- task walking ability.

• Composites Research
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• v.27 no.3
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• pp.90-95
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• 2014

Cure shrinkage during cure process of polymer matrix composites develope residual stress that cause some structural deformation, such as spring-in, spring-out and warpage. The carbon/epoxy prepreg used in this study is Hexply M21EV/34%/UD268NFS/IMA-12K supplied by Hexcel corp. Cure shrinkage and degree of cure measured by TMA(thermomechanical analyzer) and DSC(differential scanning calorimetry). Cure shrinkages are measured by TMA within a temperature range of $140{\sim}240^{\circ}C$ in a nitrogen atmosphere, and degree of cure determined by the heat of reaction using dynamic and isothermal DSC runs in argon atmosphere. As a result, the cure shrinkage is increased dramatically in a degree of cure range between 27~80%. the higher the cure temperature, the lower the degree of cure occurring to begin cure shrinkage.

• Polymer(Korea)
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• v.36 no.5
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• pp.593-598
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• 2012

Solution polymerization behaviors of L-lactide using single and mixed aluminium catalyst systems were studied. Triisobutylaluminium (TIBA) was a reference catalyst for mixing. For the $Al(O-i-Pr)_3$/TIBA catalytic systems, the molecular weight of the resulting polylactide (PLA) decreased as the composition of $Al(O-i-Pr)_3$ increased. The higher molecular weight shoulder was revealed in their GPC curve. At TIBA of 80 mol% a bimodal GPC curve was shown. The conversion in the trimethylaluminium (TMA)/TIBA catalysts system decreased as the composition of TMA in the mixed catalyst increased. The conversion in the trioctylaluminium (TOA)/TIBA catalysts system decreased as the composition of TOA in the mixed catalyst increased. The unimodal molecular weight distribution was observed with the TOA/TIBA catalyst systems. The Al compounds-mixed catalyst could produce a higher molecular weight shoulder in the GPC curve.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.19-23
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• 2003

Dimethylamine (DMA) is the immediate precursor of carcinogenic N-nitrosodimethylamine (NDMA). In vitro and in vivo experiments using whole strawberries, and garlic and kale juices were conducted to determine concentrations of DMA and trimethylamine (TMA) in foods and urine. Experimental diets [an amino-rich diet as nitrosatable precursors in combination with added nitrate-containing drinking water without (TD1) or with whole strawberries or garlic or kale juices (TD2, TD3 and TD4, respectively), or a diet of low in nitrate and amino (TD5) were incubated in simulated saliva and gastric juices at 37$^{\circ}C$ for 1 hour. We also studied the urinary excretion of DMA and TMA after consumption of the experimental diets (TD1~TD5). Urine samples were obtained for 18 hrs after consumption of experimental diets and concentrations of DMA and TMA were measured in the digested diet and urine. The DMA concentration after incubation in experimental diets (TD1~TD5) was 4.7$\pm$0.3, 6.7 $\pm$0.2, 7.9$\pm$0.2, 7.1$\pm$0.2 and 0.3$\pm$0.1 mg/kg, respectively. Urinary excretion of DMA (TD1~TD5) was 22.0$\pm$5.0, 28.3$\pm$4.3, 29.2$\pm$4.1, 27.4$\pm$4.5 and 20.4$\pm$3.1 mg/18 hr, respectively. Consumption diets with added strawberries or juices of kale or garlic increased urinary TMA and DMA, suggesting that those precursors were excreted and not converted to the carcinogen, NMDA.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.50.1-50.1
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• 2009

Transparent conductive oxides (TCOs) play an important role in thin-film solar cells in terms of low cost and performance improvement. Al-doped ZnO (AZO) is a very promising material for thin-film solar cellfabrication because of the wide availability of its constituent raw materials and its low cost. In this study, AZO films were prepared by low pressurechemical vapor deposition (LPCVD) using trimethylaluminum (TMA), diethylzinc(DEZ), and water vapor. In order to improve the absorbance of light, atypical surface texturing method is wet etching of front electrode using chemical solution. Alternatively, LPCVD can create a rough surface during deposition. This "self-texturing" is a very useful technique, which can eliminate additional chemical texturing process. The introduction of a TMA doping source has a strong influence on resistivity and the diffusion of light in a wide wavelength range.The haze factor of AZO up to a value of 43 % at 600 nm was achieved without an additional surface texturing process by simple TMA doping. The use of AZO TCO resulted in energy conversion efficiencies of 7.7 % when it was applied to thep-i-n a-Si:H thin film solar cell, which was comparable to commercially available fluorine doped tin oxide ($SnO_2$:F).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.1
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• pp.27-30
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• 2004

In this paper, a new small size Lateral Trench Electrode Power MOSFET is proposed. This new structure, called "LTEMOSFET"(Lateral Trench Electrode Power MOSFET), is based on the conventional MOSFET. The entire electrode of LTEMOSFET is placed in trench oxide. The forward blocking voltage of the proposed LTEMOSFET is improved by 1.6 times with that of the conventional MOSFET. The forward blocking voltage of LTEMOSFET is 250V. At the same size, a increase of the forward blocking voltage of about 1.6 times relative to the conventional MOSFET is observed by using TMA-MEDICI which is used for analyzing device characteristics. Because the electrodes of the proposed device are formed in trench oxide, the electric field in the device are crowded to trench oxide. We observed that the characteristics of the proposed device was improved by using TMA-MEDICI and that the fabrication of the proposed device is possible by using TMA-TSUPREM4.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.323-326
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• 2003

In this paper, a new small size Lateral Trench Electrode Power MOSFET is proposed. This new structure, called "LTEMOSFET"(Lateral Trench Electrode Power MOSFET), is based on the conventional MOSFET. The entire electrode of LTEMOSFET is placed in trench oxide. The forward blocking voltage of the proposed LTEMOSFET is improved by 1.6 times with that of the conventional MOSFET. The forward blocking voltage of LTEMOSFET is 250V. At the same size, a increase of the forward blocking voltage of about 1.6 times relative to the conventional MOSFET is observed by using TMA-MEDICI which is used for analyzing device characteristics. Because the electrodes of the proposed device are formed in trench oxide, the electric field in the device are crowded to trench oxide. We observed that the characteristics of the proposed device was improved by using TMA-MEDICI and that the fabrication of the proposed device is possible by using TMA-TSUPREM4.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.543-560
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• 1991

Practitioners are aware of the presence of friction between bracket system and archwire during sliding movement of teeth. Clinically a mesiodistally applied force must exceed the frictional force to produce a tooth movement. The objective of this study were to determine, on a dry condition, changes in magnitude of friction with respect to load, 3rd order inclination (Torque), archwire materials and ligature type. Three wire alloys (Stainless Steel, TMA, NiTi) in two wire sizes (.016, .016x, .022 inch) were examined respect to two bracket system (Straight, Standard), and two ligature type (Metal, Plastic ligature) at three levels of load (100g, 150g, 200g). The results were as follows; 1. Frictional resistance was found to increase with increasing load for S.S., TMA, NiTi. 2. The straight bracket system was exhibited more frictional force than standard bracket system for .016x, .022 S.S. tightly ligated metal ligature. But, torque difference did not increase friction for loose metal ligature & plastic ligature. 3. Regardless of the ligature type, torque and load, stainless steel wire sliding against stainless steel exhibited the lowest friction, and TMA sliding against stainless steel exhibited the highest friction. 4. The loose stainless steel ligature generated lower frictional resistance than plastic ligature in all experimental groups. 5. The following factors affected friction in decreasing order; wire material ligature type, and load.