• Elastomers and Composites
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• v.6 no.2
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• pp.65-72
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• 1971

The purpose of this study is to establish an effective way to utilize the application of EPDM-Polymer blends. First of all, the physical properties for EPDM/NR blends and compounding agents were studied. The results are shown as follows: 1. In blending, tensile strength and tear strength decreased with increase in EPDM contents. It was not effective more than the ratio of EPDM/NR is 50/50. 2. Elongation is influenced by blending, especially the ratio of EPDM/NR is 50/50. 3. It was found that both the resistance for ozone and aging were much improved after blending.

• Clinics in Shoulder and Elbow
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• v.13 no.1
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• pp.79-85
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• 2010

Purpose: To evaluate the results from arthroscopic repair versus debridement for full-thickness tears of the upper subscapularis tendon. Materials and Methods: Ninety-nine patient outcomes were evaluated and compared prospectively. Sixty-nine patients with full-thickness tears of the upper subscapularis tendon underwent arthroscopic repair (group I) and thirty patients underwent simple debridement (group II) between May 2003 and October 2007. In all patients, the tear was localized to the superior one third of the upper subscapularis tendon. The results of the treatment were assessed by evaluating the UCLA, ASES, and VAS for pain and internal rotation strength scores before and after the operation. Results: In groups I and II, UCLA, ASES, VAS, and internal rotation muscle power (perfect score = 5) scores were improved after surgery. In comparing group I and group II, the UCLA and VAS scores were not significantly different (p>0.05), while the ASES and internal rotation strength scores were significantly different (p<0.05). Conclusion: The arthroscopic repair of full-thickness tears of the upper subscapularis tendon was a better surgical method than simple debridement.

• Journal of Korean Orthopaedic Sports Medicine
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• v.9 no.2
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• pp.104-108
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• 2010

Purpose: To evaluate the correlation between Korean Shoulder Scoring System and Isokinetic muscle strength test for allowance of the return to unrestricted activities after rotator cuff disease treatment. Materials and Methods: This study examined 59 patients with impingement syndrome and 36 patients with rotator cuff tear. KSS and isokinetic muscle strength were analyzed and we sought to evaluate the correlation between total score or each functional parameter scores of KSS and isokinetic muscle strength deficit with Pearson's correlation test. Results: We found a weak negative correlation between and the total KSS score and the endurance test as well (r<0.346). The correlation between the manual muscle test of KSS and isokinetic strength deficits was not significant (p>0.05). Conclusion: The isokinetic muscle strength deficit had a weak correlarion between total score or the edurance test of KSS. Our results suggest that the Isokinetic muscle strength test may be needed for return to normal activity after treatment.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.61-68
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• 2011

Purpose: We evaluated the clinical outcome after arthroscopic repair in full thickness rotator cuff tears with and without delamination. Materials and Methods: From March 2006 to October 2008, we included 48 consecutive shoulders (31 males, 17 females; mean age 57.6 years; 45~68) who had arthroscopic double row repair for fullthickness tears of the rotator cuff. Mean rotator cuff tear size was 2.8 cm (range: 1.2~3.6) and the techniques of tendon-to-bone fixation varied according to the presence of delamination; separate row fixations of bursal and articular layer were used in delaminated tear. The mean follow-up was 26 months (range: 18~33) and functional and structural results were evaluated by American Shoulder and Elbow Surgeons (ASES), University of California at Los Angeles (UCLA) scale, isokinetic strength testing and magnetic resonance imaging (MRI) obtained mean 8 months (range:6~13) postoperatively. The patterns of delamination, age, sex, symptom duration, size of tear, satisfaction rate, retear rate ware compared and significance was set at p values < 0.05. Results: Postoperative functional shoulder score improved significantly in 44 shoulders (91.7%). Delamination was observed in 15 shoulders (31%) and it extended proximally and posteriorly in the majority of shoulders, and the articular layer was thicker (8/15, 53%) and more retracted (9/15, 60%) compared with the superficial bursal layer. Final follow up functional shoulder scores showed no differences between non-delaminated and delaminated tears and the presence of delamination had no correlations with sex, symptom duration, tear size and satisfaction rate, however, older age had more delaminated tears (p=0.041). Follow up MRI in 29 shoulders revealed that fourteen (48%) shoulders had complete healing; nine (31%), partial healing; six (21%), complete retear but the half of the retear group showed favorable clinical results. 79% (15/19) in non-delaminated tear and 80% (8/10) in delaminated tear were judged as healed tendon on MRI and double-layer double row repairs in delaminated tears resulted in nearly same rate of structural integrity of single-layer double row repairs (p=0.165). Conclusion: The incidence of delamination in our series was 31% and older age had more delaminated tears. Sex, symptom duration, preoperative size of the tear, functional results and satisfaction rate had no significant correlations with the presence of delamination. Nearly the same postoperative structural integrity was noted in both delaminated and non-delaminated tears.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.574-580
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• 1992

Chitin was isolated from the residue of enzymatically hydrolyzed crab, Portunus trituberculatus, and further deacetylated by alkaline boiling to make chitosan. The physical properties of chitosan solution and its film forming properties were examined. The functional characteristics of chitosan film were compared to those of cellophane, polyvinyl chloride (PVC) and polyethylene (PE) films. The proximate chemical composition of chitin obtained from crab residue was 6.95% nitrogen, 0.3% crude ash and 4.57% moisture and the product yield was 12.8% based on a dry material basis. The degree of deacetylation of chitosan was $79{\sim}92%$ and $70{\sim}86%$ as determined by IR spectroscopy, and $70{\sim}86%$ as determined by colloid titration method each respectively. The chitosan at 1% acetic acid solution showed distinct pseudoplastic flow behavior. The flow behavior index and consistency index were 0.8886, 0.2084 $MPa{\cdot}s^n$ for 0.4% solution and 0.8498, 0.6190 $MPa{\cdot}s^n$ for 0.8% solution, respectively. The chitosan film had the highest tensile strength $(888 kg/cm^2)$ and water permeability $(100\;g/m^2{\cdot}24\;hrs)$ among the tested films, but relatively low elongation property (49%). It showed the similar tear strength (90kg/cm) and light permeability (87.7%) to other films tested in spite of the relatively high haze value (12.5%). As the thickness of chitosan film increased from 0.025 to 0.050 mm, the tensile strength of film decreased distictively, and the degree of elongation, tear strength, and water permeability of film also decreased slightly. Whereas the light permeability of film did not change and the haziness of film slightly increased by the increase of film thickness.

• Polymer(Korea)
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• v.26 no.2
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• pp.218-226
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• 2002

For the preparation of high resilience polyurethane (PU) foams with polyether type cell openers which have different ethylene oxide (EO) content, molecular weight and chain structure, the influences of tell opener structure on the kinetics, rheology, structural stability, open cell content and mechanical properties of the obtained foam were investigated. It was observed that urea formation reaction was delayed with the increase of EO content and incorporation of ester linkage in cell opener molecule and was relatively independent on the molecular weight. With the rheological studies, the decreases of viscosity and storage modulus were confirmed for the increase of EO content and molecular weight, so that the resulted foam had low structural stability and high open cell content. The cell opener having ester linkage in molecule exhibited the lowest values of viscosity and storage modulus and the obtained foam has high open cell content. However, the structural stability increased due to the larger intermolecular interaction of ester linkage. The hardness, tensile strength, tear strength and elongation of foam were deteriorated with increase of EO content and molecular weight of tell opener. On the other hand, the cell opener having ester linkage in molecule improved the values of tensile strength, tear strength and elongation.

• Elastomers and Composites
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• v.39 no.1
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• pp.71-76
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• 2004

4,4'-Methylenebis(2-chloroaniline)(MOCA) has been widely used as a crosslinking agent, but classified as a toxic chemical. Thus, its use will be limited in the near future. In this research, polyurethane coating films were prepared using 1,3-propanediolbis(4-aminobenzoate)(PDBA) as an alternative to MOCA. The base part was prepared by melting MOCA or PDBA in polyoxypropylene($M_n$=2000), followed by the addition of the various additives. The NCO-terminated toluene diisocyanate prepolymer was used as a curing agent. The polyurethane coating films were prepared by mixing the base part with the curing agent in an appropriate ratio at room temperature. The polyurethane coatings prepared using PDBA exhibited higher initial viscosity, but much longer pot lift, compared to those prepared using MOCA under the same conditions, due to lower reactivity of PDBA. The tensile strength and tear strength of the coating films were much weaker. However, the pot life, tensile strength, elongation, and tear strength of the coating films, prepared using PDBA in the presence of an increased amount of Pb(II)-octoate, were close to those of the coating films prepared using MOCA. Thus, it was concluded that PDBA can substitute MOCA in the preparation of polyurethane coatings as long as the reactivity of PDBA is enhanced using appropriate amounts of the catalyst or other appropriate catalyst.

• Fashion & Textile Research Journal
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• v.14 no.4
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• pp.635-640
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• 2012

In this study, thermoplastic urethane (TPU) coating yarns were prepared at various extruding temperatures. The fine structure and mechanical properties of resultant TPU coating yarns examined by the wide angle X-ray diffractometer (WAXD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and tensile test. TPU coating yarns (prepared at extruding temperatures at $175^{\circ}C$) were confirmed as a stable fine structure that obtained excellent tensile strength and flexibility. The C samples prepared by optimized conditions made by TPU woven floor mat. The structure of the woven mat is $4{\times}4$ basket weave and have laminated with the EVA foam to obtained final TPU woven floor mat products. The resultant TPU woven floor mat was obtained to 1.5MN of tensile strength, 22% of the elongation, and 0.2MN of tear strength. The weight loss abrasion and the resilience by the ball rebound of the TPU-woven floor mat was prior to those of the PVC subsequently, we were able to develop a woven floor mat with TPU coating yarn and produce an eco-friendly high valuable woven floor mat using an interior product.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.3
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• pp.74-82
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• 2004

The botanical antimicrobial agent prepared from citrus fruits (BAAC) was prepared to provide inhibitory ability to packaging paper The BAAC diluted in 0.5% and 1% starch solution respectively was applied to packaging paper by the thin coating technique. The antimicrobial packaging paper displayed great inhibitory effect against the putrefying microbes including fungi, yeast and bacteria. Tn addition to antimicrobial activity of the packaging papers, their physical properties such as tensile strength, burst strength, tear strength and bending stiffness could be improved by simultaneous treatment with starch. Both the item packaging by tissue paper and the outer packaging by corrugated boxes, which were treated by the thin coating of BAAC and starch, exhibited great ability in preserving freshness of stored mandann oranges. The more treatment of BAAC was made in the packaging paper, the greater freshness-preserving ability was generated.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.13 no.3_4
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• pp.89-95
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• 2007

Functional packaging paper containing botanical antimicrobial agent (BAAG) and inorganic zeolite was developed for antimicrobial activity and adsorption of ethylene gas of the paper. The physical properties of the packaging paper showed different characteristics with addition of BAAG and functional fillers: both tensile strength and burst strength were decreased, but both stiffness and tear strength were slightly increased. Zeolite also contributed to fast removal of ethylene gas known as aging hormone of fruits and vegetables. Alkyl ketene dimer (AKD) was greatly effective to endow the packaging paper with water repellency property.