• Carbon letters
• /
• 제13권3호
• /
• pp.182-186
• /
• 2012

A new model and resultant equation for the coagulation of acrylonitrile monomers in precipitation polymerization are suggested in consideration of the surface tension (${\gamma}$) and cohesive energy density ($E_{CED}$). The equation was proven to be quite favorable by considering figure fittings from known surface tensions and cohesive energy densities of certain organic solvents. The relationship between scale value of surface tension (${\gamma}$/M) and cohesive energy density of monomers can be obtained by changing the coagulation bath component for effective precipitation polymerization of acrylonitrile in wet spinning.

• Biomolecules & Therapeutics
• /
• 제30권6호
• /
• pp.553-561
• /
• 2022

Chronic myeloid leukemia (CML) is a slowly progressing hematopoietic cell disorder. Sphingosine kinase 1 (SPHK1) plays established roles in tumor initiation, progression, and chemotherapy resistance in a wide range of cancers, including leukemia. However, small-molecule inhibitors targeting SPHK1 in CML still need to be developed. This study revealed the role of SPHK1 in CML and investigated the potential anti-leukemic activity of hirsuteine (HST), an indole alkaloid obtained from the oriental plant Uncaria rhynchophylla, in CML cells. These results suggest that SPHK1 is highly expressed in CML cells and that overexpression of SPHK1 represents poor clinical outcomes in CML patients. HST exposure led to G2/M phase arrest, cellular apoptosis, and downregulation of Cyclin B1 and CDC2 and cleavage of Caspase 3 and PARP in CML cells. HST shifted sphingolipid rheostat from sphingosine 1-phosphate (S1P) towards the ceramide coupled with a marked inhibition of SPHK1. Mechanistically, HST significantly blocked SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways. In addition, HST can be docked with residues of SPHK1 and shifts the SPHK1 melting curve, indicating the potential protein-ligand interactions between SPHK1 and HST in both CML cells. SPHK1 overexpression impaired apoptosis and proliferation of CML cells induced by HST alone. These results suggest that HST, which may serve as a novel and specific SPHK1 inhibitor, exerts anti-leukemic activity by inhibiting the SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways in CML cells, thus conferring HST as a promising anti-leukemic drug for CML therapy in the future.

• 한국전자거래학회지
• /
• 제8권3호
• /
• pp.241-257
• /
• 2003

XML(eXtensible Markup Language)은 인터넷과 e-비즈니스를 위한 글로벌 표준으로서 전자상거래의 보급 속도에 따라 XML의 활용도가증가하고 있다. 이러한 환경에서 전자상거래시에 교환되는 전자문서의 보다 안전한 보안서비스를 제공하기 위한 방안이 필요하다. XML정보보호기술 중 XML키 관리 규격(XKMS)은 다양하고 복잡한 기능의 전자상거래 애플리케이션에서 전자문서의 서명을 검증하거나 암호화하는 공개키를 관리하는 프로토콜을 정의한다. 본 논문에서는 XML 기반 보안서비스 특성에 착안하여 안전한 전자상거래를 위한 XML키 정보서비스(X-KISS)에 대한 분석과 표준안에 근거한 서비스 참조 모델을 제시하고, 기반 되는 서비스 컴포넌트를 구현하여 서비스 모델링을 수행하였다. 본 논문에서 제시된 참조 모델은 식별정보가 주어졌을 때, 필요로 하는 공개키 위치와 식별자 정보, 공개키 연결 기능을 제공한다. 구현한 클라이언트 서비스 컴포넌트의 요청 및 검색 쓰레드의 비율을 제한하여 실시간 키 검색에 대한 컴포넌트의 최소 성능을 분석하였다. 본 논문의 서비스 모델링은 향후 국내 e-비즈니스 프레임워크 구성 시 표준적 인 보안 모델을 구현할 수 있는 지침을 제공할 것이다.

• Journal of international Conference on Electrical Machines and Systems
• /
• 제3권4호
• /
• pp.433-445
• /
• 2014

Single phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). As the fundamental part of large scale PECs, single-phase VSC has a wide range of applications. In the paper, as first, on the basis of the concept of the discontinuous pulse-width modulation (DPWM) for three-phase VSC, a new DPWM of single-phase VSR is presented by means of zero-sequence component injection. Then, the transformation from stationary frame (abc) to rotating frame (dq) is designed after reconstructing the other orthogonal current by means of one order all-pass filter. Finally, the presented DPWM based single-phase VSR is established analyzed and simulated by means of MATLAB/SIMULINK. In addition, the DPWMs presented by D. Grahame Holmes and Thomas Lipo are discussed and simulated in brief. Obviously, the presented DPWM can also be used for single-phase VSI, GCI and APF. The simulation results show the validation of the above modulation algorithm, and the DPWM based single-phase VSR has reduced power loss and increased efficiency.

• Bulletin of the Korean Chemical Society
• /
• 제34권2호
• /
• pp.489-494
• /
• 2013

An improved method for the preparation of monomethine cyanine dyes with quinoline nucleus by one-pot three-component using 1-methyl-2-quinolinethione, quaternized 2- or 4-methylheterocyclic compounds and methyl p-toluenesulfonate as starting materials was described. Compared with the traditional methods, the new synthetic method reduced the reaction steps, shortened the reaction time, avoided the separation and purification of the intermediate and reduced cost. The dyes absorbed in the region 478.0-563.0 nm and had molar extinction coefficients of $1.3{\times}10^4-9.4 {\times}10^4L\;mol^{-1}\;cm^{-1}$. Their fluorescence maxima and Stokes shifts were in the range of 525.2-594.4 nm and 16.2-80.6 nm in different solvents, respectively. From the spectral properties of the dyes in different solvents, it could be found that the ${\lambda}_{max}$ of the dyes were shorter in protonic solvents, and showed hypsochromic shifts with the increase of polarity of the solvents.

• 대한안전경영과학회지
• /
• 제6권3호
• /
• pp.211-235
• /
• 2004

Component based design is perceived as a key technology for developing advanced real-time systems in a both cost- and time effective manner. Already today, component based design is seen to increase software productivity, by reducing the amount of effort needed to update and maintain systems, by packaging solutions for re-use, and easing distribution. Nowdays, a thousand and one companies in If(Information Technology) industry such as Sl(System Integration) and software development companies, regardless of scale of their projects, has spent their time and endeavor on developing reusable business logic. The component software is the outcome of software developers effort on overcoming this problem; the component software is the way propositioned for quick and easy implementation of software. In addition, there has been lots of investment on researching and developing the software development methodology and leading If companies has released new standard technologies to help with component development. For instance, COM(Component Object Model) and DCOM(Distribute COM) technology of Microsoft and EJB(Enterprise Java Beans) technology of Sun Microsystems has turned up. Component-Based Development (CBD) has not redeemed its promises of reuse and flexibility. Reuse is inhibited due to problems such as component retrieval, architectural mismatch, and application specificness. Component-based systems are flexible in the sense that components can be replaced and fine-tuned, but only under the assumption that the software architecture remains stable during the system's lifetime. In this paper, It suggest that systems composed of components should be generated from functional and nonfunctional requirements rather than being composed out of existing or newly developed components. about implements and accomplishes the modeling for the Product Control component development by applying CCD(Contract-Collaboration Diagram), one of component development methodology, to MRP(Material Requirement Planning) System

• Earthquakes and Structures
• /
• 제17권6호
• /
• pp.635-647
• /
• 2019

Tests and theoretical studies for seismic responses of a transmission tower-line system under coupled horizontal and tilt (CHT) ground motion were conducted. The method of obtaining the tilt component from seismic motion was based on comparisons from the Fourier spectrum of uncorrected seismic waves. The collected data were then applied in testing and theoretical analysis. Taking an actual transmission tower-line system as the prototype, shaking table tests of the scale model of a single transmission tower and towers-line systems under horizontal, tilt, and CHT ground motions were carried out. Dynamic equations under CHT ground motion were also derived. The additional P-∆ effect caused by tilt motion was considered as an equivalent horizontal lateral force, and it was added into the equations as the excitation. Test results were compared with the theoretical analysis and indicated some useful conclusions. First, the shaking table test results are consistent with the theoretical analysis from improved dynamic equations and proved its correctness. Second, the tilt component of ground motion has great influence on the seismic response of the transmission tower-line system, and the additional P-∆effect caused by the foundation tilt, not only increases the seismic response of the transmission tower-line system, but also leads to a remarkable asymmetric displacement effect. Third, for the tower-line system, transmission lines under ground motion weaken the horizontal displacement and acceleration responses of transmission towers. This weakening effect of transmission lines to the main structure, however, will be decreased with consideration of tilt component.

• 디지털융복합연구
• /
• 제14권3호
• /
• pp.171-179
• /
• 2016

본 연구의 목적은 현재 전 세계적으로 시장을 선도하고 있는 핀테크의 성공적인 비즈니스 모델의 개념을 도출하고 국내의 핀테크 산업에 대한 비즈니스 모델의 구성요소들에 대한 전략을 제안하려 한다. 비즈니스 모델은 전략적적인 차원에서 제시되고 있지만 결국 기업이 가치를 창출하는 데 있다. 기존의 연구에서 비즈니스 모델에 대한 개념적 특성과 구성요소들을 검토하고 핀테크의 산업분야에 적용하고자 한다. 본 연구 내용을 통해 핀테크의 비즈니스 모델에 대한 개념을 이해할 수 있었으며, 성공적인 시장진입을 위한 비즈니스 모델의 구성요소의 방향성을 구축할 것을 제안하고 있다. 본 연구에서는 Alexander Osterwalder 등이 제안한 비즈니스 모델 캔버스를 이용하여 핀테크의 비즈니스 모델의 구성요소에 대한 개념적 이해를 분석하였다. 이 제안된 비즈니스 모델의 구성요소는 목표고객, 가치제안, 채널, 고객관계, 핵심 자원, 핵심 활동, 핵심 파트너십, 수익원 및 비용구조로 구성되어 있다. 이러한 구성요소들을 기반으로 핀테크 산업의 성공적인 시장진입과 정착을 위한 개념적 정의를 분석하였다. 이러한 핀테크의 비즈니스 모델의 구성요소들의 분석을 통해 비즈니스 모델의 지향성을 밝히고자 하였다.

• Membrane and Water Treatment
• /
• 제8권4호
• /
• pp.381-393
• /
• 2017

The inorganic components in tobacco sheet extract have significant influence on the sensory taste of the cigars and the harmful component delivery in cigarette smoke. To identify the contributions of the divalent inorganic components on harmful components delivery in cigarette smoke, a self-made selective electrodialysis was assembled with monovalent ion-selective ion exchange membranes. The influences of current density and extract content on the desalination performance were investigated. Result indicates that the majorities chloride, nitrate, and sulfate ions were removed, comparing with 50-60% of potassium and only less than 10% of magnesium and calcium ions removed in the investigated current density. The permselectivity of the tested cations across the Selemion CSO cation exchange membranes follows the order: $K^+>Ca^{2+}>Mg^{2+}$. A current density of $15mA/cm^2$ is an optional choice by considering both the energy consumption and separation efficiency. When the extract contents are in the range of 7%-20%, the removal ratios the potassium ions are kept around 60%, while the removal ratios of the calcium and magnesium ions fluctuate in the range of 16-27% and 8-14%, respectively. The tobacco smoke experiments indicated that the divalent metal ions have dual roles for the harmful component delivery in cigarette smoke. The divalent potassium and calcium ions were unfavorable for the total particulate matter emission but beneficial to decrease the HCN delivery in the mainstream cigarette smoke. The selective electrodialysis is a robust technology to decrease the harmful component delivery in cigarette smoke.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
• /
• pp.978-980
• /
• 1987

This paper presents a scheme of $16{\times}16$ VLSI crosspoint chip as a key Component in future broadband switching network operating at bit rates UP to 140Mbit/s using space division switching technique. First, functional requirements of the chip are investigated in terms of a large switching unit. Then, a regeneration circuit to provide reshaping of previsiously switched signals is presented.