• 대한기계학회논문집
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• 제17권11호
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• pp.2752-2761
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• 1993

The purpose of this study is to confirm the decreasing problems of residual bending strength, and the fracture machanism experimentally when CFRP composite laminates are subjected to Foreign Object Damage. Composite laminates used for this experiment are CFRP orthotropy laminated plates, which have two-interfaces [O/sub 6//sup o//90/sub 6//sup o/]sub sym/ and four-interfaces [O/sub 3//sup o//90/sub 6//sup o//O/sub 3//sup o]/sub sym/. When the specimen is subjected to transverse impact by a steel ball, the delamination area generated by impact damage is observed by using SAM(Scanning Acoustic Microscope). also, Thefracture surfaces obtained by three-point bending test were observed by using SEM (Scanning Electron Microscope). Then, fracture mechanism was investigated based on the observed delamination area and fracture surface. The results were summarized as follows; (1) It is found that for the specimen with more interface, the critical delamination energy is increased while delamination-development energy is decreased. (2) Residual bending strength of specimen A is greater than that of Specimen B within the impact range of impact energy 1. 65J (impacted-side compression) and 1. 45J (impacted-side tension). On the other hand, when the impact energy is beyond the above ranges, residual bending strength of specimen A is smaller than that of specimen B. (3) In specimen A and B, residual strength of CFRP plates subjected to impact damage is lower in the impacted-side compression than in the impacted-side tension. (4) In the case of impacted-side compression, fracture is propagated from the transverse crack generat-ed near impact point. On the other hand, fracture is developed toward the impact point from the edge of interface-B delamination in the case of impacted-side tension.

• Clinics in Shoulder and Elbow
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• 제24권2호
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• pp.72-79
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• 2021

Background: A midshaft clavicle fracture is a common fracture that typically responds well to open reduction and internal fixation (ORIF). However, refracture can occur after implant removal (IR). This study aimed to analyze the rate of refracture and related factors after removal of the locking compression plate (LCP) for displaced midshaft clavicle fractures. Methods: We retrospectively reviewed the medical records of 201 patients who had undergone ORIF with LCP for midshaft clavicle fractures after IR after bony union from January 2011 to May 2018 at our institute. We evaluated basic demographic characteristics and radiographic parameters. All patients were treated with an LCP for primary fracture. The patients were divided into two groups: a refracture group that experienced a second fracture within 1 year after IR and a no-fracture group. Results: There were four cases (1.99%) of refracture; three were treated conservatively, while one was treated surgically. All patients achieved bony union. The average interval between refracture and IR was 64 days (range, 6-210 days). There was a significant difference in classification of fractures (AO Foundation/Orthopaedic Trauma Association [AO/OTA] classification) between the two groups. However, other patient demographics and radiographic measurements between refracture and IR, such as bone diameter, showed no significant difference between the two groups. Conclusions: This study showed that one in 50 patients suffered from refracture after removal of the LCP. Thus, if patients desire IR, the surgeon should explain that there is a relatively higher possibility of refracture for cases with simple or segmental fractures than for other types of fracture.

• Journal of Yeungnam Medical Science
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• 제15권2호
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• pp.254-262
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• 1998

골수의 손상정도률 민감하게 반영하는 Tc-99m 표지 항과립구항체 면역신티그라피를 이용하여 척추압박골절의 원인을 감별할 수 있는지를 알아보기 위하여, 척추압박골절 환자중에서 병리조직학적(수술 혹은 생검) 혹은 3개월 이상의 임상경과를 추적 관찰하여 원인이 밝혀진 16명의 환자를 대상으로 Tc-99m 표지 항과립구항체 면역신티그라피의 결과를 분석하였다. 16명의 환자중 외상이나 골다공증에 의한 압박골절 부위가 16부위 (8명), 전이암에 의한 압박골절이 3부위 (3명), 결핵에 의한 압박골절이 6부위 (5명) 이었다. 외상이나 골다공증과 같은 양성원인에 의한 척추압박골절 16 부위 모두 척추뿌리, 추궁판, 가시돌기의 섭취는 정상이었고, 척추체는 섭취저하가 7례, 섭취결손이 8례, 섭취정상이 2례에서 관찰되었다. 결핵에 의한 압박골절 6례에서 척추체의 섭취결손이 6례 모두, 척추뿌리의 섭취결손이 5례에서 관찰되었고, 가시돌기와 추궁판의 섭취결손은 발견되지 않았다. 전이암에 의한 3례의 경우는 2례에서 척추체, 척추뿌리, 추궁판, 가시돌기의 섭취결손이 보였고, 1례에서는 척추체와 가시돌기에만 섭취결손이 관찰되었다. Tc-99m 표지 항과립구항체 면역신티그라피의 단층영상에서 섭취결손부위를 평가함으로서 양성원인과 병적원인에 의한 척추압박골절의 원인의 감별에 도움이 될 수 있을 것으로 사료된다.

• Journal of Acupuncture Research
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• 제32권4호
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• pp.147-156
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• 2015

Objectives : This study aims to evaluate the effectiveness and safety of Korean medicine for a thoracolumbar compression fracture. Methods : We searched six Korean databases (DBPIA, Korean Studies Information Service System, Oriental Medicine Advanced Searching Integrated System, National Digital Science Library, Research Information Sharing Service, KoreaMed) (up to June 2015) and the Journal of Korean Acupuncture and Moxibustion Society. Unpublished studies were also searched. Clinical research, other than case reports involving less than 10 patients, were eligible. The effectiveness and safety of Korean Medicine was analyzed. The 'Risk of Bias' was assessed using the 'Risk of Bias' assessment tool for non-randomized studies as well as the Cochrane Collaboration's 'Risk of Bias' tool. Results : We found 12 before-after studies (374 patients). There was no randomized trial. All studies combined at least three different types of Korean medicine treatments. The period of treatment varied between less a week and 154 days. All the included studies reported improvements in pain, functional disability related to lower back pain, global assessment, and benefits in the compression ratio of a fractured vertebrae and skin temperature measured by digital infrared thermal imaging in comparison with the baseline. However, all studies had a high risk of bias and three studies reported mild adverse events. Conclusions : There is no randomized trial for the role of Korean medicine for patients with a thoracolumbar compression fracture. The effectiveness and safety of Korean medicine for this population remains unclear. Findings in this review are seriously biased due to observational design and a high risk of bias included in the studies. Future high-quality randomized trials are warranted.

• Journal of Acupuncture Research
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• 제18권4호
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• pp.55-67
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• 2001

Objective : This study was performed to evaluate result of thoracolumbar compression fracture patient treated with Hua-Tuo-Jia-Ji-Xue(華佗夾脊穴) acupuncture. Methods : This clinical study was carried out 50 cases with thoracolumbar compression fracture, who had been admitted from January, 2000 to February, 2001, in the department of acupuncture and moxibustion, Hanseo University Oriental Medical Hospital. We divided two groups; A group, without using Hua-Tuo-Jia-Ji-Xue(華佗夾脊穴) acupuncture and the other group is B group, by using Hua-Tuo-Jia-Ji-Xue(華佗夾脊穴) acupuncture. Results : 1. The distribution of sex and age, 78% were female, and 84% were most above there sixties. 2. In the duration of symptom, the largest group was over 4 weeks. 3. In the distribution of cause, the largest group was "lifting heavy object"(32%) and the next was "slip down"(26%). 4. In the distribution of injured level was L1 body the most(19.6%) and T12 body was the next. 5. In the distribution of clinical symptoms on the admission, the largest group was lumbosacral pain(18%). 6. The result of treatment due to the duration of admission, 17case(34%) was the most above "Fair" during the 2~3 weeks. 7. The result of treatment, Good and Fair were the same in 24case(48%). 8. The duration of treatment was longer in high grade of clinical symptom. 9. B group discharged above good state 60% higher than A group.

• 대한두개안면성형외과학회지
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• 제12권1호
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• pp.12-16
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• 2011

Purpose: This study examined the biomechanical stability of four different plating techniques in the experimental model of mandibular subcondyle fracture. Methods: Twenty standardized bovine tibia bone samples ($7{\times}1.5{\times}1.0cm$) were used for this study. Each of the four sets of tibia bone was cut to mimic a perpendicular subcondyle fracture in the center area. The osteotomized tibia bone was fixed using one of four different fixation groups (A,B,C,D). The fixation systems included single 2.0 mm 4 hole mini adaption plate (A), single 2.0 mm 4 hole dynamic compression miniplate (B), double fixation with 2.0 mm 4 hole mini adaption plate (C), double fixation with a 2.0 mm 4 hole mini adaption plate and 2.0 mm 4 hole dynamic compression miniplate (D). A bending force was applied to the experimental model using a pressure machine (858 table top system, $MTS^{(R)}$) until failure occurred. The load for permanent deformation, maximum load of failure were measured in the load displacement curve with the chart recorder. Results: Double fixation with a 2.0 mm 4 hole mini adaption plate and a 2.0 mm 4 hole dynamic compression miniplate (D) applied to the anterior and posterior regions of the subcondyle experimental model showed the highest load to failure. Conclusion: From this study, double fixation with an adaption plate and dynamic compression miniplate fixation technique produced the greatest biomechanical stability. This technique may be considered a useful means of fixation to reduce the postoperative internal maxillary fixation period and achieve early mobility of the jaw.

• 대한치과기공학회지
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• 제41권2호
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• pp.93-100
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• 2019

Purpose: This study is making a dog dental prosthesis using digital dental technology. The mechanical strength of the prosthetic material was observed in terms of compressive strength and fracture pattern. Methods: The experiment was performed using dog mandibular molars. The teeth were scanned and modeled. The specimens were made of zirconia, PMMA and Ni-Cr. The specimens were subjected to a vertical compression test with an artificial cancellous bone in UTM tester. Vertical compressive strength and fracture behavior of specimen were observed. Results: The result of observing the compressive load between specimen and artificial bone were $184.8{\pm}5.7N$ in the zirconia specimen, $185.6{\pm}8.9N$ in the PMMA specimen, and $184.4{\pm}4.0N$ in the Ni-Cr alloy specimen. Compression marks of artificial bones were observed. The fracture strength of specimen was observed. The fracture strength of the zirconia specimen was an average of 1,381.4N. The fracture strength of the PMMA specimen was an average of 572.2N. Conclusion: The crown made of three kinds(zirconia, PMMA, Ni-Cr alloy) of materials has the strength to chew about the artificial bone. zirconia and PMMA have vertical compressive strength applicable to medium dog dental prosthetic materials.

• 대한정형외과스포츠의학회지
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• 제4권2호
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• pp.128-132
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• 2005

주5일제 근무의 도입으로 인하여 스포츠 활동에 참여하는 인구가 많이 증가하였으며 그 결과로 스포츠 손상의 빈도가 비례하여 증가하는 추세이다. 겨울 스포츠 중 최근 청소년과 젊은이들 사이에 인기를 얻고 있는 스노우 보드로 인한 척추 관련 손상은 그 문헌 보고가 많지 않은 실정으로 저자들이 스노우 보드 손상에 따른 요추의 압박 골절 환자를 경험하여 이를 보고하고자한다.

• 소성∙가공
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• 제21권4호
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• pp.228-233
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• 2012

In this study, powder compaction of AZO (alumina doped zinc oxide) powder was performed with a MTS 810 test system using a cylindrical die having a diameter of 10mm. Pressure-density curves were measured based on the load cell and displacement of the punch. The AZO powder compacts with various densities were formed to investigate the mechanical properties such as fracture stress of the AZO powder as a function of the compact density. Two types of compression tests were conducted in order to estimate the fracture stress using different loading paths: a diameteral compression test and a uniaxial compression test. The pressure-density curves of the AZO powder were obtained and the fracture stress of the compacted powders with various densities was estimated. The results show that the compact pressure dramatically increases as the density increases. Based on the experimental results, calibration of the modified Drucker-Prager/Cap model of the AZO powder for use in FE simulations was developed.

• 소성∙가공
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• 제25권6호
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• pp.402-408
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• 2016

A manufacturing technology of carbon fiber composites with thermoplastic polymer pellets and continuous woven fiber was investigated using a compression molding process. To secure the impregnation of resin into the porosity of fabric the composite specimens were prepared with general injection-molding grade polypropylene pellets and low viscosity polycarbonate pellets. Tensile tests of polypropylene and polycarbonate composites were performed. Polycarbonate composites showed higher fracture strength than that of polypropylene composites because of the difference of matrix properties. However, the increase rate of strength was lower than that of polypropylene composites due to the difference of coherence between matrix and reinforcement. To investigate the effect of carbon fiber volume fraction on the fracture strength variation polypropylene composites with different volume fraction were compression molded and tensile tests were performed together. It was shown that the fracture strength of the polypropylene composites increased by 3.2, 5.4 and 6.9 times with the increase of carbon fabric volume fraction of 0.256, 0.367, and 0.480, respectively.