• Journal of Conservation Science
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• v.25 no.2
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• pp.161-169
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• 2009

The objective of this study was to investigate stability of Korean Paper(Hanji) which is being sold in the Korean markets according to aging treatment. In order to know the aging characteristics, the optical and mechanical properties of before and after wet and dry-heat aging treatment were examined. The optical and mechanical properties were shown higher reduction in the dry-heat aging treatment compared to the wet-heat aging treatment. The Soonji (pure mulberry Hanji) made from black mulberry bast pulp was shown a great reduction of the brightness and whiteness, and increase of the opacity in the aging treatment. On the other hand, in case of mechanical properties, the breaking length of Soonji made from white mulberry bast pulp was significantly higher than that of the others, and the tensile strength was shown drastic reduction in according to Soonji made from black mulberry bast pulp in the aging treatment. The burst strength of Soonji made from black and white mulberry bast pulp was shown the similar value in the wet-heat aging treatment. The folding endurance of Soonji made from white mulberry bast pulp was significantly higher than that of others before and after aging treatment. Consequently, Hanji was affected sensitive in the temperature compared to the humidity. Meanwhile, the density and color of the chinese ink was no significant changes before and after wet and dry-heat aging treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.298-305
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• 2005

Antimicrobial packaging paper was prepared with a powder-type botanical antimicrobial agent from grapefruit seed extract (BAAG) and zeolite according to TAPPI standard method. The functional fillers containing BAAG fixed to CaCO$_3$ and zeolite were well retained in the fiber network by a retention aid such as cationic polyacrylamide, which was ascertained by the ash contents of paper and the SEM microphotographs. With addition of the functional fillers to paper, tensile strength and burst strength of the paper decreased by interference of the functional fillers with interfiber bonding but bending stiffness and tear strength increased by improved elastic modulus of paper and delayed transfer of tearing energy. Finally, it was confirmed that the antimicrobial packaging paper might be able to be used to make packaging bags and corrugated containers due to the minor deterioration of strength properties.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.94-101
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• 2023

In this study, the development performance of the head bars, which is SD700, was experimentally evaluated at the RC (reinforced concrete) or SFRC (steel fiber reinforced concrete external beam-column joint. A total of 10 specimens were tested, and variables such as steel fibers, length of settlement, effective depth of the beam, and stirrups of the column were planned. As a result of the experiment, the specimens showed side-face blowout, concrete breakout, and shear failure depending on the experimental variables. In the RC series experiments with development length as a variable, it was confirmed that the development strength increased by 26.5~42.2% as the development length increased by 25-80%, which was not proportional to the development length. JD-based experiments with twice the effective depth of beams showed concrete breakout failure, reducing the maximum strength by 31.5% to 62% compared to the reference experiment. The S-series experiment, in which the spacing of the shear reinforcement around the enlarged head reinforcement was 1/2 times that of the reference experiment, increased the maximum strength by 8.4 to 9.7%. The concrete compressive strength of SFRC was evaluated to be 29.3% smaller than the concrete compressive strength of RC, but the development strength of SFRC specimens increased by 7.3% to 12.2%. Accordingly it was confirmed that the development performance of the head bar was greatly improved by reinforcing the steel fiber. Considering the results of 92% and 99% of the experimental maximum strength of the experiment arranged with 92% and 110% of the KDS-based settlement length, it is judged that the safety rate needs to be considered even more. In addition, it is required to present a design formula that considers the effective depth of the beam compared to the development length.

• Clinics in Shoulder and Elbow
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• v.15 no.1
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• pp.8-15
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• 2012

Purpose: The object of this study was to investigate the difference in torque and pullout strength between the standard anchor insertion (5.0 mm) with a small awl (3.7 mm) and larger anchor insertion (6.5 mm), with a standard awl (5.0 mm) in osteoporotic humeral head. Materials and Methods: The embalmed 24 paired cadaveric shoulders were assigned to either Group A or B. After measuring the bone mineral density (BMD) of the ROI (region of interest) in the humeral head, 5.0 mm suture anchors were inserted using a 3.7 mm awl in Group A1, and the same 5.0 mm anchors were inserted using a 5.0 mm awl in Group A2. The 5.0 mm anchors were inserted using a 5.0 mm awl in Group B1, and 6.5 mm anchors were inserted using a 5.0 mm awl in Group B2. We measured the torques at the time of the anchor insertion and pullout strengths. Results: There was no significant difference in the BMD between the groups. The torque of A1 (20.6 $cN{\cdot}m$) was significantly higher than that of A2 (13.2 $cN{\cdot}m$), and the torque of B2 (20.8 $cN{\cdot}m$) was significantly higher than that of B1(12.1 $cN{\cdot}m$). However, the difference in the increased torque between group A and B was not significant. The pullout strength of A1 (204.2 N) was significantly higher than that of A2 (152.9 N), and the pullout strength of B2 (210.9 N) was significantly higher than that of B1 (149.5 N). However, the difference in the increased pullout strength between Group A and B was not significant. Conclusion: In severe osteoporosis, the use of a larger suture anchor with a standard awl increased the torque and pullout strength significantly, in comparison to the use of the same sized suture anchor and awl. If there is an inadequate interval between the anchors on the greater tuberosity, the use of a 3.7 mm awl and 5.0 mm anchor will be beneficial compared to that of a 5.0 mm awl and 6.5 mm anchor, considering that an increase in the pullout strength does not depend on the awl size.

• The Journal of the Korean bone and joint tumor society
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• v.11 no.2
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• pp.155-159
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• 2005

Purpose: To find out the pathologic symptoms, and the incidence and clinical significance of the coexistence of internal derangement of knee(IDOK) in osteochondroma around the knee. Materials and Methods: We retrospectively reviewed forty-five patients under 20 years of age treated with the excision of the osteochondroma around the knee between 1995 and 2004. We analyzed age, gender, past history, family history, solitary or multiple osteochondroma, presenting pathologic symptoms, and causes of IDOK. Results: IDOK was confirmed in nine(20%) among the 45 cases. There were four cases of multiple osteochondromatosis, and IDOK was coexisted in one case among them. The most common presenting pathologic symptoms were painless mass of 38 cases, however 9 cases among them had joint pain for IDOK. There were 7 cases of meniscal tears and 2 of pathologic plica. Discoid meniscus was found in 4 cases among the 7 cases of meniscal tears. Conclusion: Coexistence of osteochondroma around knee and IDOK in this study probably represents a coincidence rather than a real association. However the incidence might be not low, special study and close observation should be done.

• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.162-172
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• 2021

Purpose We retrospectively evaluated the technical success rate and long-term efficacy of fluoroscopy-guided synovial cyst rupture followed by an intra-articular steroid injection at the post-laminectomy lumbar facet. Materials and Methods We selected subjects who had undergone a fluoroscopy-guided synovial cyst rupture with simultaneous intra-articular steroid injection within 6 months of MRI and demonstrated a symptomatic facet joint synovial cyst at the level of a previous lumbar laminectomy. Fourteen patients were enrolled, and we determined whether cyst rupture and symptom improvement were achieved after each procedure. The degrees of symptom improvement were categorized into 4: 1) symptoms improved (30% or more reduction, based on pre-procedural and post-procedural Numerical Pain Rating Scale scores), 2) symptoms not improved, 3) patient underwent surgery after injection, and 4) loss of follow-up. Results The success rate of percutaneous synovial cyst rupture decreased with repeated procedures (62.5% for the first procedure and 0% to 33.3% for additional procedures). However, 80% of the patients had symptom improvement with the procedures, overall. The surgery rate was 14.3% in 14 patients. Conclusion For patients with post-laminectomy symptomatic lumbar facet joint synovial cysts, fluoroscopy-guided synovial cyst rupture with intra-articular steroid injection may be an effective and less invasive treatment before considering a surgical approach.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.153-161
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• 2023

The worldwide effects of COVID-19 have led to a surge in online shopping and contactless services. The consumption pattern has caused the issues such as the environmental pollution together with the increase of plastic waste. Reducing the reliance on the petroleum based plastic use for the package and replacing it with environmentally friendly material are the simple ways in order to solve those problems. Paper is an eco-friendly product with high recyclability as the food packaging materials but has still poor barrier properties. A barrier coating on surface of the paper can be achieved with the proper packaging materials featuring water, gas and grease barrier. Polyethylene (PE) or polypropylene (PP) coatings which are generally laminated or coated to paper are widely used in food packaging applications to protect products from moisture and provide water or grease resistance. However, recycling of packaging containing PE or PP matrix is limited and costly because those films are difficult to degrade in the environment. This study investigated the recyclability of modified acrylic emulsion coating papers compared to PE and PP polymer matrixes as well as their mechanical and gas barrier properties. The results showed that PE or modified acrylic emulsion coated papers had better mechanical properties compared to the uncoated paper as a control. PE or PP coating papers showed strong oil resistance property, achieving a kit rating of 12. Those papers also had a significantly higher percentage of screen reject during the recycling process than modified acrylic coated paper which had a screen rejection rate of 6.25%. In addition an uncoated paper had similar value of a screen rejection rate. It may suggest that modified acrylic emulsion coating paper can be more easily recycled than PE or PP coating papers. The overall results of the study found that modified acrylic emulsion coating paper would be a viable alternative to suggest a possible solution to an environmental problem as well as enhancing the weak mechanical and poor gas barrier properties of the paper against moisture.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.602-608
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• 2006

Carbon fiber (CF) reinforced papers using polyacrylonitrile (PAN) based CF and wood pulp were prepared by varying the lengths and the concentrations of CF, and the basis weight of paper to investigate adhesive state between CF and pulp, and physical properties and electrical conductivity of the paper. The reinforcement was caused by physical entanglement and adhesion at the interface of the different fibers rather than by chemical bonds. The tear strength and the thickness of the paper increased as increasing the concentration of CF, while the tensile and the burst strength of the paper decreased. The improved dispersion of CF in the paper was obtained from mixing shorter CF, but the maximum electrical conductivity of the paper was gained from mixing 10 mm chopped CF. The electrical conductivity of the paper increased sharply from 2 wt％ to 8 wt％ of CF showing S-curve, and increased linearly as increasing the basis weight of the paper. Therefore, in order to improve the electrical conductivity and the physical property of the paper, the increase of basis weight of the paper is also important as the increase of CF content in the paper.

• Journal of the Korean Arthroscopy Society
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• v.8 no.2
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• pp.82-88
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• 2004

Purpose: In this study, we intended to ascertain the benefit of KT-2000 Knee arthrometer(KT-2000) in the diagnosis of ACL(Anterior cruciate ligament) injury by comparing the anterior displacement of normal knee with that of ACL deficient knee. Materials and Methods: We designated two examiners to measure the anterior displacement of the knee joint of 30 healthy individuals, using KT-2000, at 30$^{\circ}$ flexion setting of muscle full relaxation, contraction, 25$^{\circ}$ internal rotation and 25$^{\circ}$ external rotation and analyzed these results according to the variables and measured the preoperative anterior displacement of the ACL injured knee in the 30 patients who have gone through an arthroscopic ACL reconstruction later. Results: The results of examiner 1 are 6.5${\pm}$1.5 mm, 2.5${\pm}$0.9 mm, 4.8${\pm}$1.2 mm, 6.4${\pm}$1.3 mm in right knee and 5.6${\pm}$1.3 mm, 2.1${\pm}$0.8 mm, 4.5${\pm}$1.2 mm, 5.2${\pm}$1.3 mm in left knee, in order of muscle full relaxation, contraction, 25$^{\circ}$ internal rotation and 25$^{\circ}$ external rotation. The results of examiner 2 are 6.9${\pm}$1.2mm, 2.9${\pm}$1.1mm, 5.6${\pm}$1.6mm, 6.9${\pm}$1.5mm in right, 5.5${\pm}$1.7 mm,1.9${\pm}$0.9 mm, 5.1${\pm}$1.9 mm, 5.7${\pm}$1.6 mm in left knee, The side to side difference of examiner 1 in the setting of muscle relaxation is 0.9${\pm}$1.0 mm. The anterior displaement of ACL injured knee is average 11${\pm}$2.93 mm and difference of average 6.5${\pm}$2.31 mm form that of normal. In comparison between the right and left knees of healthy individuals, the both results of two examiners showed the statistical difference in the setting of muscle full relaxation but, the results showed the side to side difference below 2 mm in 25case(83%), 21case(70%) respectively and above 3 mm in just 1 case. In the comparison between the normal and ACL injured knees, the results show the statistical difference of the side to side difference in the setting of muscle relaxation(p<0.05). Conclusion: The KT-2000 result is affected by relaxation of muscles around knee, flexion angle of knee joint, rotation of tibia, the strength of displacing force, time of the test and physical factors as height and weight. However, the Accuracy of diagnosis of ACL injury by KT-2000 will increase if the examiner is skillful and the tests are made on the exact position of knee joint.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.29-36
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• 1991

The effects of heat treatment on fatigue crack growth behavior were studied in continuously reinfored, magnesium-based composite (FP/ZE41A). Following an earlier TEM investigation, specimens were thermally aged to modify the interfacial zone between the alumina fibers and mg alloy matrix. The fatigue crack growth experiments were conducted with specimens having the fiber orientation normal to the crack growth direction(longitudinal) and also specimens with the fibers oriented parallel to the crack growth direction(transverse). A comparision of the fatigue crack growth behavior indicates that aged longitudinal specimens are more resistant to fatigue crack growth than as-fabricated longitudinal specimens. Conversely, as-fabricated transverse specimens are more resistant to fatigue crack growth than aged transverse specimens. SEM observations of fiber pullout and ductile tearing on the fatigue fracture surfaces indicate that the aging weakens the strength of the fiber/matrix interface, giving rise to the observed fatigue crack growth behavior.