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이중원호근사법을 이용한 자유형상곡선의 오프셋 계산에 관한 연구
유동진(Dong-Jin Yoo) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.8
In this study a general method for computing offsets of free form curves is presented. In the method arbitrary free form curve is approximated with point series considering required tolerance. The point series are offset precisely using the normal vectors computed at each point and loop removal is carried out by the newly suggested algorithm. The resulting offset points are transformed to lines and arcs using the biarc approximation method. Tangent vectors for approximation of discrete points data are calculated by traditional local interpolation scheme. In order to show the validity and generality of the proposed method , various offsettings are carried our for the base curves with complex shapes.
자기조립단분자막을 위한 보편적이고 기능화된 긴 사슬 알킬티올 연결자의 제조
유동진 ( Dong Jin Yoo ),이경섭 ( Kyong Sub Lee ),김애란 ( Ae Rhan Kim ),남기석 ( Kee Suk Nahm ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.3
In this research, the preparation processes for making a series of ω-mercapto alkylamine 1 and ω-mercapto alkanoic acid 2 useful for studying of the self-assembled monolayer(SAM) are described. The preparation methods of the first goal materials, ω-mercapto alkylamines 1 were carried out as follows: First, ω-phthalimide alkanol 3 was synthesized from commercially available potassium phthalimide derivatives and ω-bromoalkanol in DMF at 80℃ via substitution reaction. After refluxing ω-phthalimide alkanol 3 with hydrazine hydrate in ethanol followed by treating with c-HCl, ω-aminoalkanol 4 was obtained in 76~98% yield, accompanied with side-product 5. Bromination of hydroxyl moiety of ω-aminoalkanol 4 using aqueous hydrobromic acid furnished ω-bromoamine 6 in 34~97% yields. Substitution reaction 6 with thiourea in 95% ethanol gave ω-aminoalkanthiuronium 7, which was treated with aqueous strong base and aqueous strong sulfuric acid gave desired products, ω-mercapto alkylamines 1 through overall 5 steps. The second target material, ω-mercapto alkanoic acid 2 was prepared via 2 steps. ω-bromo alkanoic acid was reacted with thiourea to give ω-thiourea alkanoic acid 7 in 69-85%, which was treated with aqueous strong base and strong acid to furnish ω-mercapto alkanoic acid 2 in 50~98%. The fabricated long-chain alkylthiol(LCAT) can be used as linkers to immobilize protein, enzyme and various kinds of biomolecules on the surface of metallic materials(Au, Pt, Ti) by SAM, and can be useful chemical tools for the application study on the surface modification of metallic materials.
유동진(Dong-Jin Yoo) Korean Society for Precision Engineering 2008 한국정밀공학회지 Vol.25 No.3
A new approach based on cone prism intersection method combined with sorting algorithm is proposed for the fast and robust signed distance field computation. In the method, the space bounding the geometric model composed of triangular net is divided into multiple smaller cells. For the efficient calculation of distance fields, valid points among the triangular net which will generate minimum distances with current cell are selected by checking the intersection between current cell and cone prism generated at each point. The method is simple to implement and able to achieve an order of magnitude improvement in the computation time as compared to earlier approaches. Further the method is robust in handling the traditional sign problems. The validity of the suggested method was demonstrated by providing numerous examples including Boolean operation, shape deformation and morphing of complex geometric models.
삼중 주기적 최소곡면을 이용한 조직공학을 위한 생체모사 스캐폴드의 컴퓨터응용 설계 및 제작
유동진(Dong Jin Yoo) Korean Society for Precision Engineering 2011 한국정밀공학회지 Vol.28 No.7
In this paper, a novel tissue engineering scaffold design method based on triply periodic minimal surface (TPMS) is proposed. After generating the hexahedral elements for a 3D anatomical shape using the distance field algorithm, the unit cell libraries composed of triply periodic minimal surfaces are mapped into the subdivided hexahedral elements using the shape function widely used in the finite element method. In addition, a heterogeneous implicit solid representation method is introduced to design a 3D (Three-dimensional) bio-mimetic scaffold for tissue engineering from a sequence of computed tomography (CT) medical image data. CT image of a human spine bone is used as the case study for designing a 3D bio-mimetic scaffold model from CT image data.
Paenibacillus kribbensis AM49로 발효시킨 택사의 항산화 활성 및 NO 생성 효과
유동진 ( Dong-jin Yoo ),김창은 ( Chang-eun Kim ),유수정 ( Soo-jung Yoo ),전문희 ( Moon-hee Jeon ),김수현 ( Soo-hyun Kim ) 대한본초학회 2021 大韓本草學會誌 Vol.36 No.4
Objectives : The purpose of this study was to investigate the antioxidant activities and nitric oxide (NO) production in RAW 264.7 macrophages in extract of Alisma orientale Juzep (EAOJ) and fermented extract (FAOJ) by Paenibacillus kribbensis AM49 (P. kribbensis AM49). Methods : The Alisma orientale Juzep was fermented with P. kribbensis AM49 at 37℃ for 72 hours. We measured total polyphenol and total flavonoid, DPPH radical scavenging activity, FRAP activity and reducing power by spectrometric assay in EAOJ and FAOJ at concentrations at 0.5, 1, 5, 10 ㎎/㎖. Positive control was used ascorbic acid. Furthermore, we examined effect of EAOJ and FAOJ on the cell viability and NO production in RAW 264.7 macrophages. Results : The total polyphenol and total flavonoids content of FAOJ were increased 9.16 ㎎/g, 2.59 ㎎/g to 12.58 ㎎/g, 3.45 ㎎/g. DPPH radical scavenging activity, FRAP activity and reducing power were dose dependently increased according to the treatment concentration (0.5, 1, 5, 10 ㎎/㎖) of EAOJ and FAOJ. In particular, DPPH radical scavenging activity, FRAP activity of FAOJ was significantly increased at 5, 10 ㎎/㎖. Reducing power of FAOJ at 10 ㎎/㎖ was similar to ascorbic acid at 0.1 ㎎/㎖. In addition, the cell viability and NO production in RAW 264.7 macrophages were significantly increased at the concentrations of 250, 500, 1000 ㎍/㎖. Conclusions : These results suggest that FAOJ by P. kribbensis AM49 has effects to antioxidant activity. In addition, the cell viability and NO production in RAW 264.7 macrophages were significantly increased.
음함수 곡면기법을 이용한 폴리곤 모델의 홀메움에 관한 연구
유동진(Dong-Jin Yoo) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.3
A new approach which combines implicit surface scheme and point projection method is presented in order to fill the arbitrarily shaped holes in the polygon model. In the method a trimmed surface which has an outer boundary curve is generated by using the implicit surface scheme and normal projection of point onto the base surface. The base surface is constructed by creating smooth implicit surface from the incomplete polygon model through which the surface should pass. In this paper an implicit surface is defined by a radial basis function, a continuous scalar-valued function over the domain R³. The base surface is the set of all points at which this scalar function takes on the value zero and is created by placing zero-valued constraints at the vertices of the polygon model. In order to show the validity of the present study, various hole fillings are carried out for the complex polygon model of arbitrary topology.