• Bulletin of the Korean Chemical Society
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• 제17권5호
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• pp.443-447
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• 1996

Several polysilanes with sterically bulky substituents such as poly(2-phenylpropyl)(n-hexyl)silane were prepared by Wurtz-type coupling. The polysilane products were mixtures of low-molecular-weight polymers (&bar{M};w~103) as major and high-molecular-weight polymers (&bar{M};w~106) as minor. Overall yields for polysilanes were in the range of 81-99%. λmax of liquid low MW polymers appeared at around 280 nm. Formations of solid high MW polymers were decreased by a longer reaction time and increased steric bulkiness of substituents. High MW polymers with λmax at 327 nm except crosslinked polymers were soluble in common organic solvents and found to be light sensitive. Crosslinked high MW polymer gave 21% TGA ceramic yield, compared with linear high polymer giving zero ceramic yield.

• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1233-1238
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• 1998

Transglycosylation reactions among methyl 2,3,4,6-tetra-O-methyl-D-glycopyranosides and isomeric butyl alcohols or cyclohexanol took place in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) in dichloromethane. The extent of the reaction after 1 h and 24 h from mixing was determined by gas chromatography (GC). Anomerization of the substrate took place during the course of transglycosylation, which favors α anomer regardless of the anomeric configurations of the starting glycosides. Transglycosylation also favors the a anomer regardless of the steric bulkiness of the alcohol. tert-Butyl alcohol did not give any transglycosylation, suggesting the steric hindrance of approaching the bulky alcohol to the oxonium intermediate. A mechanism for the transglycosylation have been proposed.

• 한국정밀공학회지
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• 제32권4호
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• pp.377-386
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• 2015

Joint force/torque estimation by inverse dynamics is a traditional tool in biomechanical studies. Conventionally for this, kinematic data of human body is obtained by motion capture cameras, of which the bulkiness and occlusion problem make it hard to capture a broad range of movement. As an alternative, inertial motion sensing using cheap and small inertial sensors has been studied recently. In this research, the performance of inertial motion sensing especially to calculate inverse dynamics is studied. Kinematic data from inertial motion sensors is used to calculate ground reaction force (GRF), which is compared to the force plate readings (ground truth) and additionally to the estimation result from optical method. The GRF estimation result showed high correlation and low normalized RMSE(R=0.93, normalized RMSE<0.02 of body weight), which performed even better than conventional optical method. This result guarantees enough accuracy of inertial motion sensing to be used in inverse dynamics analysis.

• 한국재료학회지
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• 제3권4호
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• pp.344-351
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• 1993

폴리(에틸렌 테레프탈레이트 -코-1,4-시클로헥실렌 디메틸렌 데레프탈레이트), P(ET-CT), 공중합체의 결정구조를 CPMAS NMR분광법을 이용하여 해석하였다. 결정화 시료에서 메틸렌기에 의한 공명 피크를 CT와 ET성분으로 분리시켜 분석한 결과, 0-20 몰%의 CT조성을 갖는 공중합체는 bulky한 CT성분이 PET결정격자에서 배제되고 66-100 몰 100%의 CT조성을 갖는 공중합체는 PCT결정격자 내부에 ET성분이 부분적으로 혼입되는 것을 확인할 수 있었다. 이와 같은 결정구조의 공중합 조성 의존성은 ET와 CT의 반복단위 길이와 결정격자의 크기가 다르기 때문인 것으로 추정된다.

• 한국의류학회지
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• 제34권10호
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• pp.1611-1620
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• 2010

This research compares the difference of each preference segments' subjective hands and sensibilities in order to analyze the correlations among preference, subjective hands, and sensibilities. Preference segments were classified into wool, acrylic, and long stitch length-preferred clusters in previous research. To evaluate the subjective hands and sensibilities of knit fabrics, the 20's and 30's women rated twelve knit fabrics by touching, using a questionnaire with a seven-point semantic differential scale. These twelve knit fabrics were differentiated by controlling the mixture ratio and stitch length using a computer-controlled automatic flat knit machine. The difference of each preference segments' subjective hands and sensibilities was determined using the conjoint analysis. The clusters perceived the subjective hands and sensibilities differently according to preferred constituent characteristics. There was no correlation between surface unevenness and preference in wool-preferred cluster, while there were negative correlations in other clusters. The acrylic-preferred cluster had a preference in coolness compared to other clusters; in addition, the long stitch-preferred cluster preferred flexibility/bulkiness and extensibility than the others. All clusters preferred modem and natural sensibilities that were caused by different constituent characteristics of knit fabrics.

• Archives of Reconstructive Microsurgery
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• 제16권1호
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• pp.23-29
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• 2007

The reconstruction of deep soft tissue defect such as pressure sore has difficult problems. Myocutaneous flaps have been used commonly as the best coverage method for pressure sore. But, they have several drawbacks such as sacrifice of functional muscle, high morbidity of the donor sites and bulkiness at the recipient site. The concepts of perforator flap has recently developed and widely used to overcome these disadvantages. Between March 2005 to July 2006, we have treated 9 patients who had pressure sore using perforator based fasciocutaneous island rotation flap. Preoperative unidirectional Doppler was used in all cases. Mean number of perforator vessels was 3.8 and flap sizes were from $7{\times}5\;cm$ to $14{\times}13\;cm$. Rotation angles of flap were from 90 degree to 180 degree. In all cases, donor sites were closed primarily. All flap survived completely and postoperative complications were wound dehiscence in 1 case, wound infection in 3 cases. The mean postoperative follow up period was 15.7 months and recurrence was not reported. We could decrease donor site morbidity and cover wound sites easily by using flap rotation and get robust blood supply without sacrifice of functional muscle. Fasciocutaneous perforator island rotation flap would be very useful for various pressure sore treatment.

• Archives of Reconstructive Microsurgery
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• 제5권1호
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• pp.56-61
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• 1996

The nasal ala and columella represent a difficult location for reconstruction, especially when defect area is covered with scar. Local flap, such as forehead flap or nasolabial flap, may result in additional facial scarring and bulkiness that require multiple thinning revisions. Recent delineation of vascular territories of the ear has allowed the use of vascularized auricular free flap in the reconstruction of large ala and columella defects. Authors reconstructed two cases of full thickiness defect of the ala and columella with auricular free flap. The pedicle of this flap is the superficial temporal artery and vein. The donor vessels were anastomosed to the facial artery and vein. The results were satisfactory cosmetically and functionally.

• Archives of Plastic Surgery
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• 제47권5호
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• pp.435-443
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• 2020

Background The innervated radial artery superficial palmar branch (iRASP) flap was designed to provide consistent innervation by the palmar cutaneous branch of the median nerve (PCMN) to a glabrous skin flap. The iRASP flap is used to achieve coverage of diverse volar defects of digits. However, unexpected anatomical variations can affect flap survival and outcomes. Methods Cases in which patients received iRASP flaps since April 1, 2014 were retrospectively investigated by reviewing the operation notes and intraoperative photographs. The injury type, flap dimensions, arterial and neural anatomy, secondary procedures, and complications were evaluated. Results Twenty-eight cases were reviewed, and no flap failures were observed. The observed anatomical variations were the absence of a direct skin perforator, large-diameter radial artery superficial palmar branch (RASP), and the PCMN not being a single branch. Debulking procedures were performed in 16 cases (57.1%) due to flap bulkiness. Conclusions In some cases, an excessively large RASP artery was observed, even when there was no direct skin perforator from the RASP or variation in the PCMN. These findings should facilitate application of the iRASP flap, as well as any surgical procedures that involve potential damage to the PCMN in the inter-thenar crease region. Additional clinical cases will provide further clarification regarding potential anatomical variations.

• 한국의류학회지
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• 제26권1호
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• pp.160-167
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• 2002

Stretch fabrics are wide-spread for high performance clothing use with requirements of fitness and adaptability to human's movement. A newly developed 100% PET high stretch fabric has excellent properties with respect to stretch, softness, bulkiness, and apparent volume compared to PET filament fabrics. The 100% PET high stretch fabric shows advantages of a dimensional stability, dye and agent adaptability in dying and finishing process, a property of stretch recovery after washing and lower production cost than that of spandex fabric. KES-FB was used to measure mechanical properties to various directions of the fabric. This study centered on whether the 100% PET high stretch fabric is suitable to quality and shape retention of fabric by testing several properties including tensile, compression, shear, bending and surface characteristic to various measuring directions. Tensile linearity showed maximum value at $0^{\circ}$ in plain and $90^{\circ}$ in twill. Shear Stiffness of plain and twill showed maximum value equally at $45^{\circ}\;and\;135^{\circ}$. Bending rigidity showed maximum value at $0^{\circ}$ in plain and $45^{\circ}$ twill. Mean deviation of MIU showed maximum value at $0^{\circ}\;and\;90^{\circ}$ in plain and $135^{\circ}$ in twill.

• 한국염색가공학회지
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• 제31권4호
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• pp.298-311
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• 2019

In this study, the mechanical properties and hand characteristics of the knitted and woven fabrics for bedding items are investigated in accordance with fabric structural parameters including the fiber type and proportion, the density of the fabric, and the knit/weave structure. The knit stitches and structure of the knit samples made an effect on tensile properties. The bending, shear and compression properties for the knit fabric were mainly affected by fiber contents of the samples. The tensile and bending properties of woven samples were highly correlated with the fabric density, thickness and structure, and those shear and compression properties were affected by the fiber contents and structure. Consequently, the primary hand values of the selected samples we developed were estimated to have good smoothness, fullness and softness, and soft feeling, which is well correlated to the parameters of consumer preference such as softness, warmness, and bulkiness. Also, their total hand values were increased.