• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1747-1751
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• 2006

The dinuclear tetraazadiphenol macrocyclic nickel(II) complexes [$Ni_2$([20]-DCHDC)]$Cl_2$ (I), [$Ni_2$([20]-DCHDC)]$(ClO_4)_2{\cdot}2CH_3CN $ (II(b)) and [$Ni_2$([20]-DCHDC)$(NCS)_2$] (III) {$H_2$[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,$0^{4,9}$,$1^{12,16}$,$0^{19,24}$]ditriacontane-2,10,12,14,16(32),17,27(31), 28,30-decane-31,32-diol} have been synthesized by self-assembly and characterized by elemental analyses, conductances, FT-IR and FAB-MS spectra, and single crystal X-ray diffraction. The crystal structure of II(b) is determined. It crystallizes in the monoclinic space group P2(1)/c. The coordination geometries around Ni(II) ions in I and II(b) are identical and square planes. In complex III each Ni(II) ion is coordinated to $N_2O_2$ plane from the macrocycle and N atoms of NCS- ions occupying the axial positions, forming a square pyramidal geometry. The nonbonded Ni…Ni intermetallic separation in the complex II(b) is 2.8078(10) $\AA$. The FAB mass spectra of I, II and III display major fragments at m/z 635.1, 699.4 and 662.4 corresponding to [$Ni_2$([20]-DCHDC)(Cl + 2H)]$^+$, [$Ni_2$([20]-DCHDC)$(ClO_4\;+\;2H)]^+$ and [$Ni_2$([20]-DCHDC)(NCS) + 6H]$^+$, respectively.

• 토지주택연구
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• 제1권1호
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• pp.113-124
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• 2010

이 연구는 신도시 및 대규모 택지개발 지구내 신교통 시스템을 도입함으로써 예상되어지는 효과를 분석하고, 이에 대한 적용 가이드라인을 제시한 것이다. 이를 위해 각 신교통 시스템 및 유형별 복합카테고리를 설정하여 지역적 특성을 반영하고자 하였으며, 신교통 시스템 도입이 기존의 대중교통체계 및 간선도로를 대체함으로써 발생되어지는 사회적 편익을 산출하였다. 분석결과, 신교통시스템 도입은 교통혼잡비용 감소, 탄소저감, 각 지자체의 친환경적 정책 입안에 뚜렷하게 기여할 수 있는 것으로 밝혀졌다. 그러나 신교통시스템의 이러한 장점에도 불구하고 이 연구에서는 신교통시스템을 도입하고자 하는 지자체에서는 무엇보다도 지역여건에 부합하는 신교통 시스템 유형을 선별하는 것이 중요함을 강조하고 있다. 특히 지자체의 무분별한 신교통시스템 도입은 대규모 택지개발사업에 의한 분양가 상승으로 이어질 가능성이 매우 높기 때문이다.

• The Korean Journal of Pain
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• 제7권1호
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• pp.74-77
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• 1994

통증치료 목적으로 구입한 본 HI-TECH 50으로 급만성 피부창상에 조사한 결과 통증완화 뿐만 아니라 창상치유에 좋은 성과를 얻었다. 특히 고질적 만성 당뇨병성 피부궤양같이 보존적 치료법으로 극히 치유가 어려운 경우에 레이저 광선을 조사함으로 해서 육아조직의 활성화는 물론이고 진통효과와 피부이식의 성공율도 현저히 향상되었음을 관찰하였다.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.761-768
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• 2007

Serratia proteamaculans HY-3 isolated from the digestive tract of a spider produces an extracellular protease named arazyme, with an estimated molecular mass of 51.5 kDa. The purified enzyme was characterized as having high activities at wide pH and temperature ranges. We further characterized biochemical features of the enzymatic reactions under various reaction conditions. The protease efficiently hydrolyzed a broad range of protein substrates including albumin, keratin, and collagen. The dependence of enzymatic activities on the presence of metal ions such as calcium and zinc indicated that the enzyme is a metalloprotease, together with the previous observation that the proteolytic activity of the enzyme was not inhibited by aspartate, cysteine, or serine protease inhibitors, but strongly inhibited by 1,10-phenanthroline and EDTA. The araA gene encoding the exoprotease was isolated as a 5.6 kb BamHI fragment after PCR amplification using degenerate primers and subsequent Southern hybridization. The nucleotide sequence revealed that the deduced amino acid sequences shared extensive similarity with those of the serralysin family of metalloproteases from other enteric bacteria. A gene(inh) encoding a putative protease inhibitor was also identified immediately adjacent to the araA structural gene.

• 대한기계학회논문집A
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• 제36권9호
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• pp.979-984
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• 2012

Antiroll-bar Assembly는 철도 차량의 롤링을 제어하도록 설계된 정밀 부품이고 안전과 편안한 승차감을 위해 중요하다. Antiroll-bar Assembly의 주부품인 토션바는 소모품으로써 프랑스에서 전량 수입되고 있다. 따라서 비용절감과 성능향상을 위해 국내 환경에 적합한 토션바 국산화 개발이 필요하다. 본 연구에서는 국내 철도에서 측정된 로드 히스토그램을 활용하여 개발된 토션바에 대한 해석 및 시험을 진행하였고, 수입품과의 비교 시험 결과 만족할만한 결과를 얻었다. 또한 토션바의 부식현상을 방지하기 위해서 스테인리스강 소재의 Ring cover를 씌울 수 있도록 설계를 변경하였다. 변경된 설계 안전성은 CAE해석과 마모시험을 통해서 검증하였다. 이 결과 설계변경에 의한 정적 및 피로에 대한 안전성은 큰 차이가 없었다. 그리고 2종류의 스테인리스강 중에서 내마모성이 우수한 소재를 채택하였다.

• 한국기계가공학회지
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• 제17권5호
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• pp.45-51
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• 2018

Roll forming refers to the production of long plate-molded products, such as panels, pipes, tubes, channels, and frames, by continuously causing the bending deformation to thin plates using rotating rolls. As the roll forming method has advantages in terms of mass production because of its excellent productivity, the size of the roll forming industry has been continuously increasing and the roll forming method is increasingly being used in diverse industrial fields as a very important processing method. Furthermore, as the roll forming method mainly depends on the continuous bending deformation of the plate materials, the time and the cost of the heterogeneous materials developed in the process are relatively large when considered from the viewpoint of plastic working because many processes are continuously implemented. The existing studies on roll forming manufacturing have reported the loss of large amounts of time and materials when the raw materials or product types were changed; further, they have stated that the use of this method can hardly guarantee the uniformity of the formed shapes and the consistency in terms of size and cannot detect all the defects occurring during the mass production and related to the dimensions. Therefore, in this research, a real-time process data-based smart roll forming method that can be applied to multiple products was studied. As a result, a roll forming system was implemented that remembers and automatically sets the changes in the finely adjusted values of the supplied quantities of individual heterogeneous materials so that the equipment setting changing time for heterogeneous material replacements or changes in the products being produced can be shortened. It also secures the uniformity of the products so that more competitive and precise slide-rail products can be mass-produced with improvements in the quality, price, and productivity of the products.

• 산업경영시스템학회지
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• 제41권4호
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• pp.238-247
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• 2018

This paper considers the problem of scheduling loading and unloading operations of a crane in a railway terminal motivated from rail-road container transshipment operations at Uiwang Inland Container Depot (ICD). Unlike previous studies only considering the total handling time of containers, this paper considers a bi-criteria objective of minimizing the weighted sum of the total handling time and tenant service time. The tenant service time is an important criterion in terms of terminal tenants who are private logistics companies in charge of moving containers from/to the terminal using their trucks. In the rail-road container shipment yard, the tenant service time of a tenant can be defined by a time difference between beginning and finishing loading and unloading operations of a crane. Thus, finding a set of sequences and time of the crane operations becomes a crucial decision issue in the problem. The problem is formulated as a nonlinear program which is improved by linearizing a nonlinear constraint in the model. This paper develops a genetic algorithm to solve the problem and performs a case study on the Uiwang ICD terminal. Computational experiment results show that the genetic algorithm shows better performance than commercial optimization solvers. Operational implications in terms of tenants are drawn through sensitivity analyses.

• 한국기계가공학회지
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• 제21권8호
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• pp.79-86
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• 2022

With the recent increase in the demand for electric vehicles, it is necessary to identify the high current safety of automobile parts. Among the automobile parts, the EPDM parts required colored parts from the existing black; therefore, it was necessary to change the basic filler from carbon black to silica. The rubber used in automobile parts is flexible and exhibits basic characteristics of high strength and elongation. However, as the filler is changed to silica, its physical properties, such as tensile strength and elongation, are lower than those of the existing carbon black base. Therefore, it is necessary to evaluate the mechanical properties with the addition of the EPDM compound using silica as a base without degrading the physical properties of EPDM. In this study, an experiment based on the additive content was performed using the mixture experimental planning method to analyze the mechanical properties according to the additive type and mixing ratio of silica-based EPDM. The mixing ratio of the four additives was set using a simplex lattice design, and the tensile strength, elongation, modulus 300%, and permanent compression reduction rate were analyzed for mechanical characteristics, and rheometer experiments were performed for vulcanization characteristics. Through statistical analysis of the measured data, the main effects and interactions of the EPDM-blended rubber additives were analyzed. These results can be used to derive a mixing ratio of additives that satisfies the required characteristics of the EPDM compound.

• 대한본초학회지
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• 제24권3호
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• pp.69-77
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• 2009

Objectives : This study was designed to investigate the effects of horse bone powder extract on the growth of longitudinal bone in adolescent male rats. Methods： Longitudinal bone growth was measured by fluorescent microscopy. To examine the effects on the growth plate metabolism, the total height of growth plate, the induction of local insulin-like growth factor-1 (IGF-1), and bone morphogenetic protein-2 (BMP-2) were measured. Results： Horse bone powder extract enhanced longitudinal bone growth and total height of the growth plate. Also, it promoted the induction of local IGF-1 and BMP-2 of the growth plate. Conclusions： This study shows that the horse bone powder extract effects longitudinal bone growth in adolescent rats and might be used for both stunted adolescents and inherent growth failure patients.

• 한국전산구조공학회논문집
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• 제36권3호
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• pp.165-171
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• 2023

건설기계와 특장차의 상부와 하부 구조를 연결하는 로터리 조인트는 축과 하우징이 회전하면서 유압을 전달하는데 오일의 유로에 누유를 방지하기 위해 여러 개의 시일이 조립된다. 시일재료는 강성이 커서 조립에 어려움이 있기 때문에 자른 후 조립하는 방법을 모색하였다. 절단면의 모양은 L형과 /형으로 하였고 유압이 작용할 때 누유 기준은 절단면에 발생하는 접촉압력으로 하였다. 시일의 구조와 재료는 이중 탄성중합체로 구성되며 강성이 큰 PE 재질만 절단한 경우에 대하여 비선형 접촉 구조해석을 수행하였다. 연구결과 절단 길이가 짧을수록 누유 방지에 유리하며 PE와 하우징이 접촉하는 윗면보다 NBR과 PE가 접촉하는 아랫면으로 누유될 가능성이 큰 것으로 나타났다.