• Title/Summary/Keyword: BIS Ratio

Search Result 209, Processing Time 0.026 seconds

The Kinetics of Transesterification between Dimethylterephthalate and 1,3-Propanediol (디메틸 테레프탈레이트와 1,3-프로판디올 사이의 에스테르교환반응에 관한 연구)

  • Na, Sang-Kuwon;Kong, Byeong-Gi;Choi, Chang-Yong;Kim, Jung-Gyu;Hong, Wan-Hae;Nah, Jae-Woon
    • Polymer(Korea)
    • /
    • v.29 no.1
    • /
    • pp.41-47
    • /
    • 2005
  • The transesterification of dimethyl terephthalate (DMT) with 1,3-propanediol (PDO) was investigated in the presence of catalyst, titanium (IV) butoxide (TBO), at 175~190 $^{\circ}C$ . The degree of transesterification reaction was measured by the output of methanol which was distilled from the reactor. The amount of methanol increased as the reaction temperature, molar ratio and catalyst concentration increased. The observed overall rate of the transesterification was third order; first order with respect to DMT, PDO, and the concentration of catalyst, respectively. Using calculated rate constants, the activation energy for transesterification was 26.93 kcal/mole. The melting temperature of bis(2-hydroxytrimethyl) terephthalate (BHTMT) was 85.2$^{\circ}C$ and heat of fusion 141.3 J/g.

Effect of Hydrophilic Polymers on the Release of BCNU from BCNU-loaded PLGA Wafer (친수성 고분자가 BCNU 함유 PLGA 웨이퍼로부터 BCNU의 방출에 미치는 효과)

  • 안태군;강희정;문대식;이진수;성하수
    • Polymer(Korea)
    • /
    • v.26 no.5
    • /
    • pp.670-679
    • /
    • 2002
  • 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) is one of the effective chemotherapeutic agents which has been used clinically for treating malignant glioma. Poly(D,L-lactide-co-glycolide) (PLGA, molecular weight: 20000 g/mole. mole ratio of lactide to glycolide 75 : 15) is a well known biodegradable polymer used as a drug carrier for drug delivery system. In this study, we investigated the BCNU release behaviour of BCNU-loaded PLGA wafers containing poly (N-vinylpyrrolidone) (PVP) or polyethyleneoxide (PEO) and the effect of hydrophilic polymers incoporated in the wafers. BCNU-loaded PLGA microparticles with or without hydrophilic polymers were prepared by a spray drying method and fabricated into wafers by direct compression. Encapsulation efficiency of BCNU-loaded PLGA microparticles containing PVP and PEO was 85 ∼ 97% and crystallinity of BCNU encapsulated in PLGA decreased significantly initial release amount and release rate of BCNU increased with the increasing PVP or PEO amount. Morphological change and mass loss of wafers during the release test were confirmed that hydration and degradation of PLGA would be facilitated with an increase of hydrophilic polymers.

Analysis for Changes of Mode Choice Behavior from Providing Real-time Schedule for Public Transportation by Smartphone Application (스마트폰 애플리케이션을 이용한 대중교통 운행정보 제공에 따른 통행자 수단선택 행태변화 분석)

  • Choi, Sung-Taek;Rho, Jeong-Hyun
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.11 no.6
    • /
    • pp.60-69
    • /
    • 2012
  • Public Transport Information Service which use smartphone Apps has received attention as the way of solution that reduced transport problem. Smartphone can offer real-time information because of a LBS(Location Based Service) system. This study try to find out which factor affect mode choice ratio of public transport, especially smartphone Apps. The result shows that rising oil price, traffic congestion, public information service with smartphone apps, BIS(Bus Information System) factors get 0.39, 0.27, 0.18, 0.16 scores with paired comparison. Younger and student respondents prefer smart phone public information service. Decision Tree shows that the most important decision factor is smartphone information service factor.

Synthesis, Characterization, and Catalytic Properties of Gp 6 Metal Complexes of 1-N,N-dimethylaminomethyl-$1^{\prime}$,2-bis(diphenylphosphino)ferrocene (FcNPP). X-ray Crystal Structure of W$(CO)_4({\eta}^2-FcNPP(O)-P,N)$

  • Kim, Tae-Jeong;Kim, Yong-Hoon;Kim, Eun-Jin;Oh, Sang-Ho;Kim, Hong-Seok;Jeong, Jong-Hwa
    • Bulletin of the Korean Chemical Society
    • /
    • v.15 no.5
    • /
    • pp.379-386
    • /
    • 1994
  • Reactions of 1',2-bis(diphenylphosphino)-l-(N,N-dimethylaminomethyl)ferrocene (FcNPP) with $M(CO)_6$ (M=Cr, Mo, W) in the presence of TMNO (Trimethylamine oxide) in a stoichiometric ratio of 1 : 1.5 : 3.5 produced a series of Gp 6 metal carbonyl derivatives with a variety of coordination modes: M(CO)$_4({\eta}^2$-FcNPP-P,P) (M=Cr, Mo, W), $M(CO)_5({\eta}^1-FcNPP-P) (M=Mo, W)\;,\; M_2(CO)_9({\eta}^1\;,\;{\eta}^2-FcNPP-P,P,N) (M=Cr, Mo)\;,\;M_2(CO)_{10}({\eta}^1\;,\;{\eta}^1-FcNPP-P,P) (M=Cr, Mo, W)\;, and\;W(CO)_4({\eta}^2-FcNPP(O)-P,N)$. All these complexes were characterized by microanalytical and spectroscopic techniques. In one case, the structure of W(CO)$_4({\eta}^2$-FcNPP(O)-P,N) was determined by X-ray crystallography. Crystals are monocinic, space group P$2_{1/C}$, with a=10.147(2), b=19.902(3), c=19.821(4) ${\AA},\;{\beta}=96.88(2)^{\circ},\;V=3974(l){\AA}^3$, Z=4, and $D_{calc}=1.64 g cm^{-3}$. The geometry around the central tungsten metal is a distorted octahedron, with the nitrogen and phosphorus atoms being cis to each other. Some of these complexes exhibited catalytic activities in the allylic oxidation and epoxidation of cholesterly acetate. Other oxidation products were also formed with the different chemical yields and product distribution depending upon the ligand and the central metal.

Study on Synthesis and Properties of Water-born Polyurethane (수분산성 폴리우레탄의 합성 및 물성에 관한 연구)

  • Cho, Ur-Ryong;Choi, Seo-Yoon
    • Elastomers and Composites
    • /
    • v.40 no.4
    • /
    • pp.249-257
    • /
    • 2005
  • Polyurethane(PU) prepolymers were prepared from polyol and diisocyanate. Unionized PU prepolymers were synthesized from poly(propylene glycol)(PPG, MW: 1000), 2,2-bis (hydroxymethyl) propionic acid(DMPA), and isophorone diisocyanate(IPDI) by prepolymer syhthesizing process. After PU prepolymers were dispersed into water, the physical properties were investigated by changing the molar ratio of polyol and diisocyanate. The results showed a stable state with the best physical properties when the prepolymer was composed of PPG/DMPA with hard segment=40%, NCO%=3.43%, [NCO]: [OH]=1.5: 1.0 in molar ratio, and was dispersed into water with 30% solid content. PU prepolymers also were synthesized with various molar ratio of PPG and DMPA. Upon higher molar ratio of DMPA, particle size of polyurethane dispersion(PUD) gradually decreased. PU-prepolymers prepared from the various blocking agents represented characteristic initial deblocking temperatures that depended on the blocking agents, and the beginning of deblocking occured within 30 mins on all the blocking agents used.

Discriminant Analysis of Marketed Liquor by a Multi-channel Taste Evaluation System

  • Kim, Nam-Soo
    • Food Science and Biotechnology
    • /
    • v.14 no.4
    • /
    • pp.554-557
    • /
    • 2005
  • As a device for taste sensation, an 8-channel taste evaluation system was prepared and applied for discriminant analysis of marketed liquor. The biomimetic polymer membranes for the system were prepared through a casting procedure by employing polyvinyl chloride, bis (2-ethylhexyl)sebacate as plasticizer and electroactive materials such as valinomycin in the ratio of 33:66:1, and were separately attached over the sensitive area of ion-selective electrodes to construct the corresponding taste sensor array. The sensor array in conjunction with a double junction reference electrode was connected to a high-input impedance amplifier and the amplified sensor signals were interfaced to a personal computer via an A/D converter. When the signal data from the sensor array for 3 groups of marketed liquor like Maesilju, Soju and beer were analyzed by principal component analysis after normalization, it was observed that the 1st, 2nd and 3rd principal component were responsible for most of the total data variance, and the analyzed liquor samples were discriminated well in 2 dimensional principal component planes composed of the 1st-2nd and the 1st-3rd principal component.

Energy Transfer from Ethidium to Cationic Porphyrins Mediated by DNA and Synthetic Polynucleotides at Low Binding Densities

  • Jung, Jin-A;Jeon, Sun-Hee;Han, Sung-Wook;Lee, Gil-Jun;Bae, In-Ho;Kim, Seog-K.
    • Bulletin of the Korean Chemical Society
    • /
    • v.32 no.8
    • /
    • pp.2599-2606
    • /
    • 2011
  • The fluorescence of ethidium bound to DNA, poly[d(A-T)$_2$], and poly[d(G-C)$_2$] at a [ethidium]/[DNA] ratio of 0.005 was quenched by porphyrins when both ethidium and the porphyrins simultaneously bound to the same polynucleotide. The quenching was tested using the "inner sphere" and the "Forster resonance energy transfer" (FRET) models, with the latter found to contribute, at least in part, to the quenching. Meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) exhibited a higher quenching and FRET efficiency than cis-bis(N-methylpyridinium-4-yl)porphyrin (BMPyP) for all of the tested DNA and polynucleotides, demonstrating that energy transfer efficiency is affected by the number of positive charges of porphyrins.

Fabrication of Roll-Printed Organic Thin-Film Transistors using Patterned Polymer Stamp

  • Jo, Jeong-Dai;Yu, Jong-Su;Kim, Dong-Soo;Kim, Kwang-Young;Lee, Eung-Sug
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2008.10a
    • /
    • pp.243-246
    • /
    • 2008
  • Roll-printed organic thin-film transistors (OTFTs) were fabricated by gravure or flexography printing using patterned PDMS stamp with various channel lengths, silver pastes, coated polyvinylphenol dielectric, and jetted bis(triisopropyl-silylethynyl) pentacene semiconductor on plastic substrates. The roll-printed OTFT parameters were obtained: fieldeffect mobility of $0.1\;cm^2/Vs$, an on/off current ratio of $10^4$ and a subthreshold slope of 2.53 V/decade.

  • PDF

Triisopropylsilyl pentacene organic thin-film transistors by ink-jet printing method

  • Park, Young-Hwan;Kang, Jung-Won;Kim, Yong-Hoon;Han, Jeong-In
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2006.08a
    • /
    • pp.1135-1138
    • /
    • 2006
  • By ink-jet printing method, organic thin-film transistors (OTFTs) having soluble 6,13-bis (triisopropylsilylethynyl) pentacene (TIPS pentacene) as an active material were fabricated. The TIPS pentacene solution was made with chlorobenzene and anisole. The solutions were printed on poly (4-vinylphenol) (PVP) dielectric layers and source/drain electrodes by piezo-type heads for bottom contact OTFTs. The dielectric layers had untreated or HMDS-treated conditions. The chlorobenzene device showed the highest field effect mobility of $0.016\;cm^2/Vs$ and the anisole HMDS-treated device shows the highest $I_{on}/I_{off}$ ratio of $10^5$.

  • PDF

Characteristics of red OEL device as thickness ratio (적색 유기 EL의 두께별 발광 특성)

  • Son, Chul-Ho;Na, Sun-Woong;Yeo, Cheol-Ho;Lee, Young-Jong;Chung, Hong-Bay
    • Proceedings of the KIEE Conference
    • /
    • 2001.07c
    • /
    • pp.1852-1854
    • /
    • 2001
  • 본 실험에서는 적색 유기 EL에서의 각 층별 두께비에 따른 발광특성을 조사하였다. 정공수송층으로 TPD(N,N'-dyphenyl-N-N'-bis(3-methyphenyl)-1, 1'-biphenyl-4,4'-diamine)를 사용하였으며, 전자수송층 및 적색 발광층으로는 DCM(4-(Dicyanomethyl)2-methy 1-6-(dimethylaminostyryl)-4H-pyrane)를 사용하여 정공 수송층과 전자수송층의 두께비를 변화시켰을 때, 발광특성을 조사하였다.

  • PDF