Synthesis and Luminescence of MeSiO_3:Eu,Bi Luminophors(Me=Mg,Ca,Sr,Ba)

The luminophors of four kinds of alkaline earth meta-silicates doped with Eu^3 and/or Bi^(3+)ion(s)were synthesized and the luminescence properties of Bi^(3+)and Eu^(3+)ions were studied.The regularities that Me(Ⅱ) ions affect the luminescence of Eu^(3+)ion sensitized by Bi^(3+)ion were investigated.The optimum composition and synthesis condition were obtained.The absorption and emission peak are situated at 283 and 353nm with the optimum concentration 0.02 mol of Bi^(3+)in CaSiO_3:Bi.In CaSiO_3:Bi,the optimum concentration of Bi^(3+)is 0.007 mol and that of Eu^(3+)is 0.040 mol.For all of the alkaline earth ions concerned in MeSiO_3:Eu,Bi,the Bi^(3+)can sensitize the Eu^(3+)and the Me(Ⅱ)ions in host and make a great difference in the adsorption hand of Bi^(3+)ion.by exciting Bi^(3+)ion,the emissions are from both Eu^(3+)and Bi^(3+)ions and the best sensitization effect is achieved when Me(Ⅱ)is Sr.

Effect of silver-nanoparticles generated in poly(vinyl alcohol)membranes on ethanol dehydration via pervaporation

Pervaporation is an important membrane separation method of chemical engineering.In this work,silver-nanoparticles-poly(vinyl alcohol)nanocomposite membranes(AgNPs-PVA)are produced for the sake of improving its potentials for pervaporation of ethanol–water mixture so that the usual opposite trend between membrane selectivity and permeation can be reduced.The nanocomposite membranes are fabricated from an aqueous solution of poly(vinyl alcohol)with silver nanoparticles via the in-situ generation technique in the absence of any reducing agent.Successful generation of the nano size silver is measured by the UV–vis spectrum showing a single peak at 419 nm due to the plasmonic effect of silver nanoparticles.Our nanocomposite AgNPs-PVA membranes are characterized using scanning electron microscope(SEM),Fourier-transform infrared(FT-IR)spectroscopy,X-ray diffraction and thermogravimetric analysis(TGA).The pervaporation tests of our new AgNPs-PVA membranes show good results since at a higher temperature and higher ethanol concentration in the feed,the prepared membranes are highly permeable for the water having stable selectivity values and therefore our membranes show better performance compared to that of the other PVA-based nanocomposite membranes.

紫外线/臭氧处理对喷墨印刷铜图文和聚酰亚胺基材间相互作用的影响

摘译近年来,喷墨印刷电子技术得到了迅速发展,因为相对于传统光刻技术需要通过真空处理、化学沉积和蚀刻来制作电路图案,喷墨印刷更简单、经济。目前,喷墨印刷已用于制作各种灵巧的电子器件,如薄膜晶体管、射频识别标签、印刷电路板等。

Highly efficient nickel/phosphine catalyzed cross-couplings of diarylborinic acids with aryl tosylates and sulfamates

Highly efficient cross-couplings of diarylborinic acids with aryl tosylates and sulfamates are reported for construction of biaryls using a tri(4-methoxyphenyl)phosphine-supported nickel catalyst system: Ni[P(4-MeOC6H4)3]2Cl2/2P(4-MeOC6H4)3 in the presence of K3PO4·3H2O in toluene. A variety of unsymmetrical biaryls could be obtained in good to excellent yields with1.5–3 mol% or 3–5 mol% catalyst loadings for aryl sulfamates and tosylates, respectively. In sharp contrast to the conventional nickel-catalyzed Suzuki coupling with arylboronic acids, arylsulfamates unexpectedly displayed a higher reactivity than the corresponding tosylates in coupling with diarylborinic acids catalyzed by the nickel/phosphine catalyst system.

Preparation and characterization of 3-dimensionally ordered macroporous SiC

Three-dimensionally (3D) long range ordered macroporous SiC ceramics were prepared through infiltrating polymethylsilane (PMS) into the 3D ordered sacrificial silica template, pyrolysis and the template removal. It was found that the pore size (84―658 nm), BET surface area (299.44―584.64 m2/g) and micropore volume (0.25―0.64 cm3/g) of the achieved porous SiC can be tailored by utilizing different sizes silica sphere templates. There exist three kinds of pores in the porous ceramics: sphere inversed pores, windows and mesopores (2―5 nm). The sphere inversed pores were packed as hcp structure and three dimensionally penetrated through the windows, and the mesopores endowed the porous ceramics surprising high BET surface areas and micropore volumes.

Preparation of patterned SiC and SiCN microstructures

Patterned SiC and SiCN microstructures were successfully fabricated on the silicon substrates by using polydimethylsiloxane (PDMS) elastometric stamp as template, polycarbosilane (PCS) and polysilazane (PSZ) as preceramic polymers. The preparing process was followed by precursor infiltration, the curing of the precursor, demolding of the template and pyrolysis of the cured preceramic polymer pattern. It shows that the dimen- sions of the ceramic patterns can be tailored by using the PDMS molds with different di- mensions. The produced ceramic microstructures can be potentially applied in high tem- perature and high pressure environments due to the advanced properties of the SiC and SiCN ceramics.

Synthesis and photoconductivities of bisazo charge generation materials

Six bisazo compounds were synthesized by coupling 2-(49-aminophenyl)-6-aminobenzoxazole as diazo component with N-phenyl-N9-(2-hydroxy-3-naphthoyl)urea derivatives,and characterized by ultraviolet and visible spectroscopy(UV-Vis),Fourier transform infrared spectroscopy(FT-IR)and elemental analysis(EA).Using these bisazo compounds as charge generation materials and CT-191(2-methyl-4-(N,N-dibenzyl)aminobenzoaldehyde-1,1-diphenylhydrazone)as charge transportation material,organic photoconductive devices were prepared.The result from photoconductivity measurement of the devices shows that the bisazo compound from N-(2-methylphenyl)-N9-(2-hydroxy-3-naphthoyl)urea has the best xerographic performance,V_(0)=600 V,V_(R)=30 V,R_(d)=15 V·s^(-1),E_(1/2)=3.5 lx·s.

Synthesis of poly(silyl ether)s via copper-catalyzed dehydrocoupling polymerization

The development of efficient method to prepare poly(silyl ether)s(PSEs)is highly desirable.Herein,an environmentally sustainable copper-catalyzed dehydrocoupling polymerization was developed with good yields and high molecular weight(up to 48,400 of Mn and up to 97%yield).Monomers of different types(AB type or AA and BB type)are suitable to afford PSEs.The PSEs show good thermal stability and low glass-transition temperature.