Synthesis and redox behavior of PEDOT/PSS and PPy/DBS structures

Electrochemical synthesis of dodecylbenzenesulfonate (DBS⁻) doped polypyrrole (PPy/DBS) onto polystyrenesulphonate (PSS⁻) doped poly(3,4-ethylenedioxythiophene) (PEDOT/PSS) modified gold EQCM electrode was studied. Monitoring of mass and potential response during PPy growth onto PEDOT underlayer revealed at least three different stages in this process. AFM study confirmed that PEDOT film morphology constantly changed during the synthesis of PPy film onto its surface. Studying of redox properties of PEDOT/PSS + PPy/DBS structures showed that PEDOT influenced the redox processes of the structure after its complete coverage with PPy suggesting the formation of three-dimensional electrode.     

New insight into the redox behavior of polyaniline

Polyaniline is one the most promising conducting polymers due to its ability to respond to environmental modifications by change in the properties. Here, we report an unprecedented redox behavior of polyaniline. Namely, propagation of reduction in thin highly organized polyaniline films immersed in acid aqueous medium (see Video 1). The films represent a homogeneous interpenetrating network of nano-sized polyaniline fibrils and water molecules. It is found that the presence of highly hydrated anions like HCOO^? favors both short- and long-range ordering, as well as the propagation of reduction in the polymer.     

Synthesis and characterization of a low band gap polymer with an aromatic oxadiazole moiety as the side chain

A novel low band gap polymer with an electron deficient oxadiazole side chain, poly[(α-bithiophene-5,5′-diyl) (5′-(2′′-phenyl-1′′,3′′,4′′-oxadiazole-5′′-phenylidene))-block-(α-bithiophene (2′′-phenyl-1″,3″,4″-oxadiazole-5″-phenylidene)quinodimethane-5, 5′-dily)] (PBTBQ-Oid), was synthesized. The polymer was soluble in common organic solvents, such as THF, chloroform and xylene. The structure of the polymer was confirmed by FT-IR, ¹H NMR. The optical spectrum revealed that it had maximum absorption among 600–700 nm. The electrochemical analysis showed that it had good electron-transporting properties and a low band gap of ∼1.10 eV.     

Synthesis and optical properties of poly(thiophene-fluorene) copolymers with benzothiazole moiety

Poly[9,9-dihexylfluorene-co-(benzothiazol-2-yl)thiophene-co-9,9′-spirobifluorene] (PF_xB_yS_z) were synthesized by palladium-catalyzed Suzuki coupling reaction. PF_xB_yS_z were characterized by FT-IR, elemental analysis, and ¹H NMR. All the copolymers showed decomposition temperatures above 400 °C and glass transition points above 180 °C, suggesting that these materials had excellent thermal stability. As the benzothiazolylthiophene content in copolymers was increased, the band gaps of copolymers decreased. All the copolymers exhibited fluorescence peaks in the visible region, and the energy transfer from fluorene to benzothiazolylthiophene units were observed.     

Synthesis and redox properties of several new oligoTTF containing functional spacer

By using two different routes, series of new bis- and tris-TTF, containing in their linker function(s) able to generate supplementary interactions in the resulting materials, have been prepared. The first route based on deprotection-realkylation strategy allowed to introduce alcohol and ketone functions. The second way, using acid chloride and hydroxy-TTF, allowed to include ester function in the linker. The electron-donating ability of this series of TTFs has been determined by CV and by SQW.     

Synthesis and studies of mesomorphism of new octa-(benzo-15-crown-5)-substituted phthalocyanines and transition metal phthalocyaninates

Previously unknown octa-(benzo-15crown-5)-substituted phthalocyanine (1) and its metallocomplexes with Ni(II) (2), Co(II) (3), Cu(II) (4), Zn(II) (5), and Cd(II) (6) are synthesized. The possible formation of mesophases of these compounds is predicted and their mesomorphic properties are studied. It is found that compounds 1, 2, and 4 exhibit high-temperature enantiotropic mesomorphism typical of discotic mesogenes, which is well consistent with the predicted results. Free phthalocyanine (1) reveals dimesomorphism according to the DSC and thermomicroscopic data. According to the studies of miscibility of compound 1 with discotic mesogene, 2,3,6,7,10,11-hexa(cyclohexanebenzoyloxy)triphenylene, which exhibits nematic mesomorphism. The second phase transition is identified as the transition to a nematic phase. According to the texture of this mixture, compound 1 was classified with discotic mesogenes that form columnar nematics (N_Col). The first phase transition of 1 from a crystal to the mesophase was identified as columnar (Col). Phthalocyanines of cobalt (3) and copper(4) revealed latent mesomorphism according to the studies of their mixtures with the chiral nematic liquid crystal of cholesterin diphenylate.     

Improved open circuit voltage of the photovoltaic device using ferrocene as a donor material

In this work, we have studied the combination of ferrocene (Fc), the donor material and fullerene derivatives such as [6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM) and the acceptor material, for fabricating organic photovoltaic devices. The effect of temperature on open circuit voltage (V_oc), short-circuit current density (J_sc), fill factor (FF) and the photoconversion efficiency (PCE), η has been investigated. By varying the annealing temperature, the V_oc, FF and PCE, η, were increased up to 140 °C and further increasing of temperature it remains constant. However, the short-circuit current density was not varied concomitantly with other parameters. The maximum PCE was observed to be 0.053% at 140 °C, which is the best annealing temperature in the present study. There have been many attempts to synthesize Fc and fullerene dyads but as an application wise very few report are available. Therefore here we have tried to use Fc and PCBM for photovoltaic device applications.     

Machining performance of TiN coatings incorporating indium as a solid lubricant

The machining and wear performance of TiN-coated and patterned carbide inserts incorporating indium as a solid lubricant are reported in this study. Cutting tests were conducted by turning hardened 4340 steel in both lubricated and dry conditions. During turning, periodic flank wear measurements were made. The chips formed during cutting were examined by scanning electron microscopy, as the condition of the chip reflects the conditions obtained during machining. Inserts subject to dry machining were also examined using optical microscopy and X-ray photoelectron spectroscopy to determine the extent of damage on the rake surface as well as the degree of material transfer. The results showed indium to be effective in reducing flank wear during lubricated machining, but little additional benefit of patterning was observed. For dry machining, some degree of improvement was noted in the patterned sample, but the degree of lubricity brought about by the indium coating was not sufficient and the overall flank wear was higher than the lubricated tests. However, the wear and damage on the rake surface along the path of the chip was reduced by the presence of the In-containing microreservoirs. An additional test was conducted using an instrument that simulates temperature effects during machining, and it was found that the lubricity achieved by In coatings is lost above 450 °C. These results suggest that the use of indium is limited to below this temperature, and above this temperature transforms to a less lubricious indium oxide.     

Synthesis of p-type conjugated dendrimers bearing phenothiazine moiety at the periphery and their light-emitting device characterization

New dendrimers bearing a phenothiazine heterocyclic building block have been successfully prepared and their absorption and emission properties have been investigated in terms of photoluminescence (PL) and electroluminescence (EL). Particularly, the EL has been studied precisely in the heterostructural devices that are fabricated with two dendrimers. The spectrum and the intensity of EL and PL are varied with the number of generation. Significant difference of the I–V–L characteristics and the external quantum efficiency in the dendrimer devices reveals that the EL performance of the higher-generation dendrimers is higher than that of the lower-generation ones. These results suggest that the site isolation between the chromophores suppresses the non-radiative decay process and reduces the interchain molecular excimer emission from the aggregated dendrimers.     

Synthesis of N-decyl-1,3-diaminopropanes and its flotation propertieson aluminium silicate minerals

1　INTRODUCTIONBauxiteisamajorsourceforaluminaproduction .Bayerprocessfeaturesshortresidencetime ,lowener gyconsumptionandhigh qualityproduct .Asare sult ,itiswidelyusedtotreatthebauxiteofalu minum/silicateratio (A/S)morethan 8.AlthoughthereareabundantaluminiumoxidemineralresourcesinChina ,mostofthemarediasporicbauxitewithhighaluminumcontent ,butlowA/Sratio .Among4 0bauxitediggings ,theaverageAl2 O3andSiO2 con tentsare 6 3.4 1%and 11.5 9% ,respectively ,whiletheaverageA/Sratiois4 6 […     

Synthesis, characterization and catalytic evaluation of zirconia-pillared bentonite for 1,3-dioxalane synthesis

The aim of this work is to study the solids obtained by pillaring Tunisian bentonite with zirconium polycations from the hydrolysis of zirconium tetrachloride. For comparative purposes, the pillaring of Wyoming montmorillonite, a reference clay, is also studied. Variations in the dialysis number, concentration of Zr solution, pH, temperature in the synthesis procedure as well as the pillaring method, affect the structure and properties of the pillared clay obtained. It has been verified that the structure of the pillared clays strongly depends on the method of preparation and the pH Zr solution in some cases, well ordered pillared clays (with basal spacings between 15 and 18.2 A) have been obtained, while in several others noncrystalline solids yielded. Delamination of the clays seems to take place both when the intercalation solutions obtained from zirconium tetrachloride have pH > 2.8 and when they are subjected to a reflux treatment. Best results were obtained at pH = 2.8 [Zr⁴⁺] = 0.1 M, at room temperature, and when using five dialysis, the direct method. The specific total surface area and micropore volume of the solids have reached the values up to 200 m² g^?1 and 0.06 cm³ g^?1, respectively. Potentiometric titration and mass titration data suggest that pillared materials produce a shift of the point zero charge toward the point zero charge of the zirconium oxide. The amount of ZrO₂ fixed have varied between 6 and 30% of the weight of the pillared samples. The activity of the zirconium pillared clay for 1,3-dioxolane synthesis has been investigated. The method of intercalation has been found to be the most suitable for this reaction.     

Synthesis and oxidation behavior of nanocrystalline MCrAlY bond coatings

Thermal barrier coating systems protect turbine blades against high-temperature corrosion and oxidation. They consist of a metal bond coat (MCrAlY, M = Ni, Co) and a ceramic top layer (ZrO₂/Y₂O₃). In this work, the oxidation behavior of conventional and nanostructured high-velocity oxyfuel (HVOF) NiCrAlY coatings has been compared. Commercially available NiCrAlY powder was mechanically cryomilled and HVOF sprayed on a nickel alloy foil to form a nanocrystalline coating. Freestanding bodies of conventional and nanostructured HVOF NiCrAlY coatings were oxidized at 1000 °C for different time periods to form the thermally grown oxide layer. The experiments show an improvement in oxidation resistance in the nanostructured coating when compared with that of the conventional one. The observed behavior is a result of the formation of a continuous Al₂O₃ layer on the surface of the nanostructured HVOF NiCrAlY coating. This layer protects the coating from further oxidation and avoids the formation of mixed oxide protrusions present in the conventional coating. The original version of this article was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Science and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8 2003, Basil R. Marple and Christian Moreau, Ed., ASM International, 2003.     

The oxidation behavior of CoCrAI systems containing active element additions

The effect of small amounts of yttrium (up to 1 wt. %) and hafnium (up to 1.5 wt.%) on the oxidation behavior of Co-Cr-Al alloys in the temperature range 1000–1200°C for times up to 1000 hr in air has been studied. The major portion of the study has been concerned with Co-10Cr-11Al base alloys. Both isothermal and cyclic tests have been carried out; the cycle used consisted of 20 hr at temperature, followed by cooling to room temperature. Both additions reduce the overall oxidation, Hf somewhat more so than Y. In part, this is due to the improved adhesion between scale and alloy reducing scale spallation at temperature, and in part due to possible modification of the Al₂O₃ grain size. The former factor is far more critical under thermal cycling conditions. Under isothermal conditions the oxidation rate increases with increasing Hf content with all but the 1.5 wt.% alloy oxidizing more slowly than the Hf-free alloy; increase in Y content has the reverse effect. Under thermal cycling conditions the 0.3 and 1.0 wt.% Hf alloys show the lowest overall weight gain. Metallographic evidence suggests that the improved scale adhesion is due principally to a pegging mechanism; the active elements promote the growth of intrusions of Al₂O₃ into the alloy. However, if the intrusions are too large, they can act as initiators of scale failure.     

活性元素氧对AA-TIG焊熔池传输行为影响的数值模拟

电弧辅助活性TIG焊(arc assisted activating TIG welding,AA-TIG焊),采用辅助电弧以Ar+O₂作为保护气体预熔待焊母材表面以形成氧化层,再进行常规TIG焊,可使熔深明显增加.文中结合AA-TIG焊熔池氧元素分布的实验研究,提出焊接熔池表面氧元素的两种不均匀分布模式,考虑浮力、电磁力和表面张力,建立了更完善的电弧辅助活性TIG焊熔池模型,模拟研究氧元素在熔池表面呈不均匀分布时,AA-TIG焊瞬态熔池中动量及能量的传输行为.假设熔池内部液态金属是湍流、不可压缩Newton流体,使用FLUENT RNG k-ε湍流模型进行处理.结果表明,当氧在熔池上表面呈非均匀分布,并且氧的不均匀分布模型为低氧模型时,熔池内部仍然以内对流流动为主.     

Iridium(III) complexes with cyclometalated styrylbenzoimidazole ligands: Synthesis,electrochemistry and as highly efficient emitters for organic light-emitting diodes

Two phosphorescent iridium complexes (psbi)₂Ir(acac) and (ppbi)₂Ir(acac) (psbi = 1-phenyl-2-styryl-1H-benzo[d]imidazole, ppbi = 1-phenyl-2-(1-phenylprop-1-en-2-yl)-1H-benzo[d]imidazole, acac = acetylacetonate) were synthesized, and their photophysical, electrochemical and electroluminescent properties were also studied. Organic light-emitting devices with these two complexes as dopant emitters having the structure ITO/NPB (10 nm)/TCTA (20 nm)/x%Ir:CBP (y nm)/BCP (10 nm)/LiF (1 nm)/Al (100 nm) were fabricated. The device based on (psbi)₂Ir(acac) exhibited a maximum brightness of 56,162 cd m^?2, while the device based on (ppbi)₂Ir(acac) gave a maximum brightness of 31,232 cd m^?2. At high brightness of 1000 cd m^?2 and 10,000 cd m^?2, high current efficiencies of 25.7 cd A^?1 and 20.7 cd A^?1 were achieved, respectively, for the (psbi)₂Ir(acac)-based EL device. For the EL device based on (ppbi)₂Ir(acac), current efficiencies of 20.1 cd A^?1 at 1000 cd m^?2 and 14.2 cd A^?1 at 10,000 cd m^?2 were observed.     

Ni-Cu-P化学沉积镀层初期冲刷腐蚀的电化学行为

利用化学镀技术,采用碱性镀液配方,在紫铜基体上制备Ni-Cu-P三元合金镀层.经EDX分析镀层中Ni、Cu和P的含量约为78.9wt％、11.4wt％和9.7wt％,属于高磷镀层.经TEM分析镀层为混晶态结构.采用管式冲刷腐蚀试验机,利用电化学测试手段,综合宏观腐蚀形貌研究镀层初期冲刷腐蚀行为.探讨在人工海水中不同冲刷流速条件下,24 h的冲刷时间内,镀层反应的电化学阻抗谱信息.结果表明,不同冲刷流速对镀层耐蚀性能有明显的影响,冲刷条件相对于静态条件,镀层耐蚀性能明显下降,当冲刷流速为6.5 m/s时,镀层耐冲刷腐蚀性能相对于冲刷流速为3m/s、4m/s时,更加良好稳定.     

Effects of milling and active surfactants on rheological behavior of powder injection molding feedstock

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SiBNC陶瓷的制备与高温行为研究

本文通过六甲基二硅氮烷与二氯甲基硅烷和三氯化硼共聚缩合的方法,合成了SiBNC陶瓷先驱体。通过FT-IR与XPS对先驱体的化学组成与结构进行了表征,平面B-N单元与Si-N单元的随机排列形成了以–Si-N-B-为骨架的理想先驱体结构。先驱体在氮气气氛下加热到800°C后转化成多元的SiBNC陶瓷,1000°C裂解后的陶瓷产率为50.1wt%。在氮气气氛下,得到的SiBNC陶瓷在1700°C下保持无定形,在1800°C下形成Si3N4 结晶。但在氩气气氛中,得到的SiBNC陶瓷在1800°C形成明显的β-SiC 与BNC2结晶。     

Synthesis and reaction behavior of calcium silicate hydrate in basic system

1　INTRODUCTIONIt skeytoseparatealuminafromsilicainaluminaproductionbyBayerorsinteringprocess .Whethersilicachangestosodiumaluminosilicatehydrateorhydro garnet(bothtitleddesilicationproduct,DSP) ,bothcontainso daoralumina .IfDSPisdischargedoutdirectly ,alargeamountofsodaandaluminawillbewasted ,meanwhiledischargedDSPwillresultinheavyenvironmentalpollu tion .InpresentitcostsalottorecoveraluminaandsodafromDSPbysinteringprocess[1] .Soitisurgenttodevel opnewhydro processtechnologytorecove…