• Macromolecular Research
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• v.15 no.6
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• pp.560-564
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• 2007

The photostabilization and cure kinetics of UV-curable, optical resins containing various formulations of photostabilizers were investigated to determine the system with the highest cure conversion and durability. Photo-DSC analysis revealed that increasing the concentration of a UV absorber (UVA) decreased both the crosslink density and the cure rate due to competition for the incident photons between the photoinitiator and the UVA, whereas including a hindered amine light stabilizer (HALS) hardly affected either the cure conversion or the cure rate due to its very low absorption of 365 nm. This result was confirmed by FTIR-ATR spectroscopy and UV-visible spectroscopy analyses. QUV ageing experiments showed that the cure conversion and durability were the highest for the UVA/HALS formulation at a ratio of 1 : 2, which is due to their synergistic action.

• Textile Coloration and Finishing
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• v.35 no.3
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• pp.151-158
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• 2023

In this study, we investigated the durability properties of the recycled leather using shaving scrap with antioxidant. Recycled leather sheets were manufactured by mixing shaving scrap and NB latex as a binder. HALS(Hindered Amine Light Stabilizer) and UVA(UV absorbers) were used as antioxidant. Mechanical properties such as hardness, tensile strength, elongation, tear strength and abrasion resistance were measured. Light aging resistance was evaluated using UV lamp and the degree of discoloration of the recycled leather sheets using a gray scale. In addition, to evaluate heat aging and UV aging, the degree of discoloration of the recycled leather sheets over time was measured using colorimeter. Washing fastness was evaluated on the degree of dyeing of recycled leather sheets for six type of multi-fiber woven fabrics (Acetate, Cotton, Nylon-66, Polyester, Acryl, Wool). To determine whether hazardous substances were detected in recycled leather sheets, the contents of arylamine and Cr 6⁺ were evaluated. As a result, when used in combination with antioxidant, the heat aging and light aging of recycled leather were improved and hazardous substance were not detected.

• Analytical Science and Technology
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• v.24 no.5
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• pp.336-344
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• 2011

The study attempted to find out any effect to prevent photo aging of epoxy resin used for conservation by way of adding UV stabilizer, one of plastic additives. Specimens were made by adding HALS and UVA UV stabilizer as each concentration to 3 kinds of epoxy resin, which are most frequently used for artifacts joining and restoration process, and aging effects were investigated through Color change, SEM, contact angle, FTIR analysis during UV aging experiments. Last, usage suitability was checked when UV stabilizer was added through Universal Tensile strength tester. In result, it is impossible to prevent decomposition of chemical structure in spite of adding UV stabilizer but in the case of epoxy A and R, it is believed that photo aging such as yellowing or crack can be minimized without giving a big influence to adhesive strength of epoxy resin through adding less than 0.1% of UVA. It is expected that above will solve photo aging problem of epoxy resin used for joining and restoration of artifacts and will extend its life as joining and restoration materials.

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.449-470
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• 2018

A review of research trends on wood surface protection for exterior use obtained the following conclusions: It has been reported that inorganic compounds such as chrome and copper used as wood preservatives can protect wood from weathering. It has been shown that precoating with hydrophobic substances such as wax and oil, UV absorbers, and HALS (Hindered Amine Light Stabilizers) enhances weathering resistance on the surface of ACQ-treated wood. Opaque coatings of paint/stains and semitransparent stains on the surface of preservative treated wood can increase the synergistic effects on prevention of weathering deterioration. Also the need for repainting periodically for the protection of the preservative treated wood surface has also been suggested. ZnO or $TiO_2$ of fine particles, metal ions such as Co, Cr, Fe, Mn, Ni and Ti, and UV absorbers such as tris-resorcinol triazine derivatives, triazine and benzotriazole were introduced as additives for preventing UV in the transparent coating on wood. Several reports showed that chemical modification such as methylation, acetylation, or alkylations have made some increases the effects of preventing weathering with the increasing weight gain of chemical formulas. In heat-treated wood, there were various contradictory reports on the resistance of weathering, and there were some other reports emphasizing the necessity of painting with UV resistance, which leads to the necessity of more advanced studies.

• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.171-178
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• 2009

A comparative analysis of the hindered amine light stabilizers (HALS) and UV abosrber (UVA) and their respective photostabilizing effect on wood plastic composites (WPCs) are reported in this study. The influence of accelerated weathering on the mechanical properties of the composites and the microscopic morphology of a degraded layer on the cross section and the surface were studied. UV absorbers were more efficient at preventing composite lightening than was UV stabilizer. The amount of whitening decreased with the increase of photostabilizers. With the addition of a UV absorber (Tinuvin360), the tensile modulus and strength of the composites increased slightly. However, the addition of a light stabilizer (Tinuvin770) and a UV absorber decreased the tensile modulus and strength of the composites. After 250 and 500 hr exposure, tensile modulus and strength of the un stabilized and stabilized composites decreased. The tensile strength of UV absorber (Chimassorb81)-stabilized composites was significantly greater than that of control and light stabilizer (Tinuvin770)- and UV absorber (Tinuvin360)-stabilized composites. UV absorber-stabilized samples showed less whitening and photodegradation than control and light stabilizer-stabilized samples.

• Journal of Gastric Cancer
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• v.4 no.3
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• pp.196-203
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• 2004

The Information Committee of the Korean Gastric Cancer Association sent questionnaires to 31 laparoscopic gastric surgeons about their personal experiences with laparoscopic gastric surgery from 2001 to 2003. Twenty-four surgeons responded to the questionnaires (response rate: $77.4\%$).The number of laparoscopic gastric surgeries from 2001 to 2003 was 1,130 and increased from 209 in 2001 to 593 in 2003. The number of operations for a gastric adenocarcinoma also increased from 87 cases in 2001 to 403 cases in 2003. Laparoscopic radical procedures, such as a laparoscopyassisted distal gastrectomy or total gastrectomy (LADG or LATG), have increased rapidly during this period. (55 cases in 2001, 150 cases in 2002, and 364 cases in 2003). Laparoscopic function-preserving gastrectomies were not performed until 2003, during which year one pylorus- preserving gastrectomy and six proximal gastrectomies were performed laparoscopically. A wedge resection for a gastric submucosal tumor was performed in 71 cases in 2001, 82 in 2002, and 103 in 2003. Hand-assisted laparoscopic surgery (HALS) was performed in 39 cases in 2001, 55 in 2002, and 49 in 2003. As for personal indications for a LADG, 14 surgeons performed a LADG only for a T1 lesion, and 5 surgeons extended their indications to T2N0 lesions. In the near future, laparoscopic procedures for gastric cancer will be widely adopted in Korea if the medical-insurance obstacle is overcome and the long-term survival results are verified.

• Journal of Gastric Cancer
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• v.5 no.4 s.20
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• pp.295-303
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• 2005

The Korean laparoscopic Gastrointestinal Surgery Study Group made a survey of laparoscopic gastric surgeries which were performed in Korea during 2004. Thirty-eight surgeons from 36 Institutions responded to the questionnaires. One thousand eighty-nine laparoscopic gastric operations were performed during 2004. The cumulative number from 1995 to 2004 was about 2,386. Seven hundred fifty-four operations for a gastric adenocarcinoma were performed during 2004 which is almost two times the number performed during 2003. Laparoscopic radical procedures, such as a laparoscopy-assisted distal gastrectomy or total gastrectomy (LADG and LATG) have increased rapidly since 2001 (55 cases in 2001, 150 cases in 2002, 364 cases in 2003 and 738 cases in 2004). Especially, laparoscopic total gastrectomies were explosively adopted last year (20 cases in 2003 and 112 cases in 2004). However, laparoscopic function-preserving gastrectomies, which included one laparoscopy-assisted pylorus-preserving gastrectomy and laparoscopy-assisted proximal gastrectomy, are rarely performed at this time. One hundred forty-two wedge resections for a gastric submucosal tumor were performed during 2004. Hand-assisted laparoscopic surgery (HALS) was performed in 39 cases in 2001, 55 in 2002, and 49 in 2003; however, only 5 such surgeries were performed during 2004. In 2003, laparoscopic bariatric surgery began, and during 2004, 49 operations were performed. In terms of indications of laparoscopic gastric surgery for adenocarcinoma, 19 surgeons performed a LADG only for a T1 lesion, and 7 surgeons extended their indications to T2N0 lesions. In the near future, laparoscopic procedures for gastric cancer will be widely adopted in Korea if the medical-insurance obstacle is overcome, and the long-term survival results are verified.