• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.28-34
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• 2012

We analysed 149 samples of Korean traditional herbal tea materials. The 156 pesticides were analyzed by GC/ECD and NPD, detected pesticides were confirmed by GC-TOF/MS. Sample preparation was performed bv multi-residue analysis method of multiclass pesticides of the Korea Food Code. The residual pesticides were detected in 22 samples(14.8%), the highest detection frequency samples are lycium and jujube. Detected pesticides in Korean traditional herbal tea materials were chlorpyrifos (5 samples), chlorothalonil (3 samples), cypermethrin (3 samples), hexaconazol (3 samples) and cyhalothrin(3 samples). The pesticide types detected in Korean traditional herbal tea materials were organophosphorus(29.2%), pyrethroids(16.7%), organochlorines (12.5%) and triazoles(12.5%). The 5 samples(lycium, jujube, chrysanthemum, balloon-flower, milk vetch root) were detected pesticides below MRLs, 2 samples(cornus fruit, cnidium) were detected pesticides unnotificated MRLs.

• Journal of the Korean Ceramic Society
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• v.33 no.7
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• pp.755-760
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• 1996

Sol-gel processing was used to prepare PZT fibers. Titanium isopropoxide Zirconium n-butoxide and lead acetate trihydrate were used as starting materials and TEA(triethanolamine) was added to form stabilized Pb-Ti-Zr complex alkoxide, Effects of catalysts and various solvents on the state of precursor sol gelation reaction fiber spinnability pyrolysis and crystallization were also investiated.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.538-547
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• 2011

In this study, eco-friendly hybrid composite boards were manufactured from green tea and wood fibers for application as interior materials with various functionalities of green tea and strong strength properties of wood fibers. In this relation, the effect of green tea content on dynamic MOEs (modulus of elasticity) of these green tea and wood fibers composite boards were investigated. The dynamic MOEs of hybrid composite boards were lower than those of control boards without green tea, and the values decreased with the increase of green tea content. Also, the dynamic MOEs appeared to be somewhat different by resin type used for board manufacture. The hybrid composite boards manufactured from $E_1$ grade urea resin, which has higher molar ratio of formaldehyde to urea than that of $E_0$ grade one, were 1.06~1.54 times higher than that manufactured from $E_0$ grade. And, the differences between hybrid composite boards manufactured from both adhesive increased with the increase of green tea content. On the other hand, high correlations were found between dynamic MOE and static bending strength performances, it was concluded that static bending strength performances could be estimated from the dynamic MOE, except for a few hybrid board types with large variations.

• Restorative Dentistry and Endodontics
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• v.40 no.4
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• pp.255-261
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• 2015

Objectives: The aim of this study was to evaluate the effect of three different drinks on the color parameters of four different restorative materials. Materials and Methods: Three different composites (Filtek Ultimate Universal Restorative, Filtek Ultimate Flowable, and Filtek Silorane, 3M ESPE) and a polyacid-modified composite resin material (Dyract XP, Dentsply DeTrey GmbH) were evaluated. Eighty-four disc-shaped specimens of 8 mm in diameter and 2 mm in thickness were prepared (n = 21 each). Color coordinates ($L^*a^*b^*$, ${\Delta}L^*$, ${\Delta}a^*$, ${\Delta}b^*$, and ${\Delta}E^*$) were measured using a $V{\dot{I}}TA$ Easyshade Compact ($V{\dot{I}}TA$ Zahnfabrik) after 24 hr of storage (baseline) and after 30 day of storage in three different beverages of black tea, Coca cola, or water (control) (n = 7). In each beverage, the specimens were stored three times a day, one hr each, for 30 day. The color changes (${\Delta}E$) were calculated and were analyzed by Kruskal-Wallis and Dunn multiple comparison test. Results: The color difference (${\Delta}E^*$) of the resin materials ranged between 1.31 and 15.28 after 30 day of immersion in the staining solutions. Dyract XP in Coca cola ($15.28{\pm}2.61$) and black tea ($12.22{\pm}2.73$) showed the highest mean ${\Delta}E^*$ value after 30 day, followed by Filtek Ultimate Universal Restorative ($5.99{\pm}1.25$) and Filtek Ultimate Flowable ($4.71{\pm}1.40$) in black tea (p < 0.05). Conclusions: The compomers displayed unacceptable color changes at the end of 30 day in all beverages. Among resin composites, the silorane based composite exhibited relatively good color stability than the others. Filtek Ultimate Universal Restorative and Filtek Flowable showed similar color changes in all beverages.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.411.1-411.1
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• 2014

This study evaluates the utility of an antibacterial microneedle composed of green tea extract (GT) and hyaluronic acid (HA), for the efficient delivery of GT. These microneedles have the potential to be a patient-friendly method for the conventional sustained release of drugs. In this study, a fabrication method using a mold-based technique to produce GT/HA microneedles with a maximum area of ${\sim}60mm^2$ with antibacterial properties was used to manufacture transdermal drug delivery systems. Fourier transform infrared (FTIR) spectrometry was carried out to observe the potential modifications in the microneedles, when incorporated with GT. The degradation rate of GT in GT/HA microneedles was controlled simply by adjusting the HA composition. The effects of different ratios of GT in the HA microneedles were determined by measuring the release properties. In HA microneedles loaded with 70% GT (GT70), a continuous higher release rate were sustained for 72 h. The in vitro cytotoxicity assays demonstrated that GT/HA microneedles are not generally cytotoxic to chinese hamster ovary cells (CHO-K1), human embryonic kidney cells (293T), and mouse muscle cells (C2C12), which were treated for 12 and 24 h. Antimicrobial activity of the GT/HA microneedles was demonstrated by ~95% growth reduction of gram negative [Escherichia coli (E. coli), Pseudomonas putida (P. putida) and Salmonella typhimurium (S. typhimurium)] and gram positive bacteria [Staphylococcus aureus (S. Aureus) and Bacillus subtilis (B. subtilis)], with GT70. Furthermore, GT/HA microneedles reduced bacterial growth in the infected skin wound sites and improved skin wound healing process in rat model.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2418-2425
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• 2021

Monazite is a phosphate mineral that contains thorium (Th) and rare earth elements. The Th concentration in monazite can be as high as 500 ppm, and it has the potential to be used as fuel in the nuclear power system. Therefore, this study aimed to conduct the techno-economic analysis (TEA) of Th extraction in the form of thorium oxide (ThO₂) from monazite. Th can be extracted from monazite through an alkaline fusion method. The TEA of ThO₂ production studied parameters, including raw materials, equipment costs, total plant direct and indirect costs, and direct fixed capital cost. These parameters were calculated for the production of 0.5, 1, and 10 ton ThO₂ per batch. The TEA study revealed that the highest production cost was ascribed to installed equipment. Furthermore, the highest return on investment (ROI) of 21.92% was achieved for extraction of 1 ton/batch of ThO₂, with a payback time of 4.56 years. With further increase in ThO₂ production to 10 ton/batch, the ROI was decreased to 5.37%. This is mainly due to a significant increase in the total capital investment with increasing ThO₂ production scale. The minimum unit production cost was achieved for 1 ton ThO₂/batch equal to 335.79 $/Kg ThO₂.

• Journal of Food Hygiene and Safety
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• v.11 no.2
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• pp.99-105
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• 1996

An attempt was made to determine the residual distribution of organochlorine and organophosphorus pesticides in the various kinds of Korean tea which were purchased form the maket. The organochlorine pesticides investigated in this study were BHC, DDT and dicofol and the organophoshorus pesticides were diazinon, EPN, fenitrothion and parathion. The pesticide residues were determined by GC-ECD and BHC was detected in all the samples and it's level were ranged from 0.00064 po 0.05995 ppm and it's average was 0.00682 ppm and DDT, dicofol and organophosphorus pesticides were not detected in all samples. The organophophorus pesticides were detected(0.0035∼0.0983 ppm) in raw materials but were not in the manufactured material and it is considered that the largely components of the pesticides is removed by drying and high temperature while the tea was manufactured. The recovery tests of the pesticides gave satisfactory results showing an average yield of 97.6% with organochlorine pesticides and 92.5% with organophoshorus pesticides and the detection limits level were 0.00008 ppm to 0.0010 ppm.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.183-190
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• 2004

The major compositions of leaf tea and flower tea were investigated to develope as a new functional tea using Korean native Camellia japonica L. Most of leaf teas, except flower tea, were considered as good materials with basic conditions for tea manufacture because water content was below 6%. Crude protein was the greatest component in roasted young leaf tea (RYLT), crude fats in roasted mature leaf tea (RMLT) and ashes in fermented young leaf tea (FYLT). Caffein were present as the highest amount (5.18%) in steamed mature leaf tea (SMLT), showing less amount than green tea. Catechin were contained as the highest amount in all kinds of teas, especially FYLT was the highest (9.57%). Tannin, which highly related with tea quality including astringent taste, color and perfume, were present as the highest amount in FYLT. Vitamin C was highly detected in the tea from flowers (22.7 mg/l00 g) rather than in the tea from leaves. The content of theanine were found in flower tea by 1,074 mg/l00 g, and had about twofold of FYLT and RYLT. Among free amino acids, glutamic acid and aspartic acid were higher detected in SMLT and RMLT while asparagine was present as higher amounts in RYLT and FYLT, expecting these components can improve tea taste. Nucleic acids and their derivatives including GMP, hypoxanthine and AMP were detected as the higher amounts by 7.86, 8.57, and $12.67\;{\mu}mol/g$, respectively, however IMP content was even reduced by all manufacturing processes. In all kinds of tea, sugars such as glucose, fructose, sucrose and maltose were detected, specially glucose and fructose were found as highest amount in RFT by 65.5 and 59.6 nmol/0.1 mg, respectively.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.23-33
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• 2019

After making tea by steaming the Burdock(Arctium lappa) nine times and drying it nine times, the ingredients and functions of the Burdock tea were compared to those of M company. The tea's calories were 346.48kcal/100g, carbohydrates were 72.75g/100g, crude protein was 11.98g/100g, and crude ash was 5.01g/100g. The total of free sugars were 31.93mg/100, among them, fructose was 26.27, sucrose was 1.27 mg/100g. The inorganic material contents were 1,476.21mg/100g of potassium, 255.96 mg/100g of calcium and 311.41 mg/100g of magnesium. The saturated fatty acids were 40.73mg/100g and the unsaturated fatty acids were 59.27mg/100g, among which the linoleic acid was 41.28mg/100g, the palmitic acid was 33.11mg/100g, the oleic acid was 10.07mg/100g and linolenic acid was 7.92mg/100g. DPPH radical scavenging was 33.9% of teas that were developed, 2.3% of M's tea for comparison, and 37.2% of indiex material. ABTS radical scavenging were 90.7% of teas developed, 85.9% of M's tea and 37.2% of index materials, and SOD like activities were 11.3% of teas developed and 50.5% of M's teas. The flavonoid content was 2.6 fold of the tea developed, 2.9 fold of M's tea and 1.7 fold of index material. The polyphenol content was 33.8 fold of teas developed, 38.9 fold of the M's tea and 13.8 fold of the index material. The sensory evaluation compare to the one-time extract and the five-time extract. Based on the one-time extract, the color were 65.9 % of the five-time extract tea were developed, 12.8 % of the M's tea. Flavour were 78.0% of the tea developed and 33.3% of the M's tea, tastes were 71.4% of the tea developed, 20.7% of the M's tea. The cart for comparison showed that while the extract decreased as we developed it, the overall symbolism decreased to 21.4% after five time extracts, the developed tea decreased to 72.1%. We believe that the developed tea will have a greater effect on preventing and improving diseases as it has a stronger antioxidant function, more effective substances, and a higher level of symbolism than the comparative M squared tea and surface substance.

• 한국약용작물학회:학술대회논문집
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• 2011.04a
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• pp.400-401
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• 2011