Investigation on sulphonated zinc oxide nanorod incorporated sulphonated poly (1,4-phenylene ether ether sulfone) nanocomposite membranes for improved performance of microbial fuel cell

Hydrothermally prepared zinc oxide nanorods are sulphonated (S–ZnO NR) and incorporated into 15% Sulphonated Poly (1,4-Phenylene Ether Ether Sulfone) (SPEES) to improve the hydrophilicity, water uptake and ion transfer capacity. Water uptake and ion transfer capacity increased to 34.6 ± 0.6% and 2.0 ± 0.05 meq g^?1 from 29.8 ± 0.3% and 1.4 ± 0.04 meq g^?1 by adding 7.5 wt% S–ZnO NR to SPEES. Morphological studies show the prepared S–ZnO NR is well dispersed in the polymer matrix. SPEES +7.5 wt% S–ZnO NR membrane exhibits optimum performance after three-weeks of continual operation in a fabricated microbial fuel cell (MFC) to produce a maximum power density of 142 ± 1.2 mW m^?2 with a reduced biofilm compared to plain SPEES (59 ± 0.8 mW m^?2), unsulphonated filler incorporated SPEES (SPEES + 7.5 wt% ZnO, 68 ± 1.1 mW m^?2) and Nafion (130 ± 1.5 mW m^?2) thereby suggesting its suitability as a sustainable and improved cation exchange membrane (CEM) for MFCs.     

数字电视播出系统的可靠性研究综述

数字电视播出系统的可靠性直接反映整个系统的质量优劣，是确保能否进行安全、可靠的电视播出的关键。为了保障电视播出的安全与可靠性，必须对硬盘化播控系统进行双机熬备扮和使用有RAID技术的硬盘播出系统的数据备份设计；同时还介绍了数字电视播出播出系统软件的设计要求和数字电视设备的寿命分析。     

Cis–trans isomerization of olefinic alcohols promoted by Rh(I) complexes

Homogeneous hydrogenation and isomerization reaction of cis-2-butene-1,4-diol has been investigated in ethanol by using tris(triphenylphosphine)chlororhodium(I), RhCl(PPh₃)₃, and triethylamine at 303 K and 0.01–0.1 MPa partial hydrogen pressure. Under reduced H₂ pressure, the geometric isomerization reaction occurs, to a high extent, leading to trans-2-butene-1,4-diol up to 93% selectivity at 90% conversion of the cis analogous. Effects of H₂ partial pressure as well as triethylamine, added phosphine and olefin concentrations on the rate of reaction and on the products distribution were also investigated. The results obtained can be interpreted on the basis of a proposed mechanism in which RhH(PPh₃)₃ is the active species. The high selectivity towards cis-trans isomerization of cis-2-butene-1,4-diol is attributed to steric factors of the Rh(I) coordinated triphenylphosphine groups.     

Thermal properties and crystalline structure of liquid crystalline poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate)

Thermal properties and crystalline structure of liquid crystalline (LC) poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate) [copoly(ET/CPT)] were investigated using differential scanning calorimetry (DSC), thermogravimetry (TGA), limiting oxygen index (LOI) measurement, electron dispersive X‐ray analysis (EDX), X‐ray diffractometry, and infrared spectrometry (IR). The thermal transition temperatures of copoly(ET/CPT) were changed with the composition. Copoly(ET/CPT) showed two thermal decomposition steps and the residues at 700°C and LOI values of copoly(ET/CPT) were almost proportional to its chlorine content. The activation energy of thermal decomposition of LC units was very low compared to that of poly(ethylene terephthalate)(PET) units. Crystal structure of copoly(ET/CPT) (20/80) was of triclinic system with the lattice constants of a = 9.98 A?, b = 8.78 A?, c = 12.93 A?, α = 97.4°, β = 96.1°, and γ = 90.8°, which is very close to that of poly(chloro‐p‐phenylene terephthlate) (PCPT) with the lattice constants of a = 9.51 A?, b = 8.61 A?, c = 12.73 A?, α = 96.8°, β = 95.4°, and γ = 90.8°. When copoly(ET/CPT)(50/50) was annealed at 220°C in vacuum, crystallization induced sequential reordering (CISR) was not observed but the heat of fusion was slightly increased due to the increase of the trans isomer content in PET units. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1286–1294, 2002; DOI 10.1002/app.10451     

Synthesis and properties of monodisperse hydroxy-terminated oligomers of 1,4-butanediol and 2,4-toluene diisocyanate

The synthesis of monodisperse hard segments containg 2,4-TDI and 1,4-butanediol by a simple technique is described. High purity material is obtained in good yield. The structures of these hard segments are confirmed by proton n.m.r., ¹³Cn.m.r., and i.r. Glass transition temperatures and melting temperatures are reported. The T_g′s of the hard segments are inversely proportional to the reciprocal of their molecular weights. The T_m′s show an odd-even effect relative to the number of 2,4-TDI units in the hard segment.     

Ru/CN催化对苯二甲酸二甲酯加氢制备1,4-环己烷二甲酸二甲酯

通过超声辅助NaBH4还原法制备了3%Ru/CN催化剂（Ru的质量分数）,该催化剂用于对苯二甲酸二甲酯（DMT）加氢制备1,4-环己烷二甲酸二甲酯（DMCD）。采用Raman、SEM、TEM、N2吸脱附、XRD、XPS等对载体和催化剂的组成、表面性质进行表征,结果表明,氮元素成功掺入碳骨架中且氮掺杂碳材料为介孔结构。研究了催化剂的用量、反应温度、H2 压力、反应时间等对催化剂加氢性能的影响。结果表明,当反应物用量为1.00 g,催化剂（含载体）用量为0.05 g,反应温度140 ℃,反应压力5.0 MPa,反应时间1 h时,DMT转化率为100%,DMCD选择性为99.3%。3%Ru/CN-1000催化剂循环使用5次后,催化剂催化性能未见明显下降,DMT转化率为98.8%,DMCD选择性为99.7%。     

Synthesis and characterization of aromatic polyisoimides derived from PMDA and para-diamines. An approach to in situ generated rigid-rod molecular composites

A new concept for the processing and fabrication of rigid-rod molecular composites aiming at the elimination or minimization of phase separation is proposed. This approach calls for a coil-like aromatic polyisoimide which is soluble and compatible with an amorphous matrix polymer or thermosettable oligomer and can undergo facile transformation to the corresponding rigid-rod polyimide in solid composite state, thus imparting the inherently high strength/high modulus properties to the final form. To this end, various synthetic routes were explored to obtain para-diamines which could afford high molecular weight and aprotic-solvent-soluble polyisoimides upon polymerization with pyromellitic dianhydride (PMDA). Four such polyisoimides were prepared, with their inherent viscosities ranging from 0.25 to 1.89 dl g⁻¹ in dimethylacetamide at 30°C. Facile thermally induced isoimide-imide conversion was demonstrated by solid-state (film) Fourier transform infrared spectroscopy. A preliminary evaluation of the compatibility of the polyisoimide/matrix resin was made. In one instance, a film prepared from the polyisoimide derived from PMDA and 3,3′,5,5′-tetramethylbenzidine (TMB) showed no visually detectable phase separation.