Reaction Between Copper Nitrate Hydrate and Methoxydimethyloctylsilane in Methanol

The reaction rate was determined for copper nitrate hydrate with methoxydimethyloctylsilane (MDOS) in methanol. The rate constants of hydrolysis and condensation were established by quantitative measurement of the product and Karl Fischer water determination. The reaction with the hydrated copper salt resulted in the phase separation of an insoluble product from the reaction mixture. The structure of the product was determined, by Fourier Transform Infrared Spectrometry (FTIR) and Nuclear Magnetic Resonance (NMR) to be a dimer of the MDOS. The results showed the alcohol, producing condensation reaction was negligible in the formation of the dimer. contrary to the case for the well-known reaction by trialkoxysilanes and tetraalkoxysilanes.     

Bi2223带材临界电流沿长度方向的统计分布

本文采用四引线法测量了Bi2223带材临界电流沿长度方向的分布,采用正态分布、对数正态分布、威布尔分布和最小极值分布对临界电流分布进行了拟合检验,确定了临界电流的最优统计分布模型.     

Bacterial sunscreen: layer-by-layer deposition of UV-absorbing polymers on whole-cell biosensors

UV-protective coatings on live bacterial cells were created from the assembly of cationic and UV-absorbing anionic polyelectrolytes using layer-by-layer (LbL) methodology. A cationic polymer (polyallylamine) and three different anionic polymers with varying absorbance in the UV range (poly(vinyl sulfate), poly(4-styrenesulfonic acid), and humic acid) were used to encapsulate Escherichia coli cells with two different green fluorescent protein (GFP) expression systems: constitutive expression of a UV-excitable GFP (GFPuv) and regulated expression of the intensely fluorescent GFP from amphioxus (GFPa1) through a theophylline-inducible riboswitch. Riboswitches activate protein expression after specific ligand-RNA binding events. Hence, they operate as a cellular biosensor that will activate reporter protein synthesis after exposure to a ligand target. E. coli cells coated with UV-absorbing polymers demonstrated enhanced protection of GFP stability, metabolic activity, and viability after prolonged exposure to radiation from a germicidal lamp. The results show the effectiveness of LbL coatings to provide UV protection to living cells for biotechnological applications.     

Single-Li~+ conductivity in ionomeric network

Ionomeric networks(IN)with lithium sulfate and sait-solvating oligo(oxyethylene)chainwere synthesized on the purpose of improving the conductivity of single-Li~+-ionic conductors.Li~+-ionicconductivity depends considerably on the salt content of the INs although the apparent degree of cross-linking is fixed in a constant of 10 mol%.As salt content(Li/O value)equals 0.0467,conductivity ofthe IN containing neither small-molecular salt nor low molecular weight plasticizer reaches a maximumof 7×10~(-6) S/cm at 25℃.Temperature-conductivity relationship of the INs shows curved Arrheninsplots,suggesting that the ionic conduction is primarily influenced by segmental motion of the polymerhost.In addition,WLF(Williams-Landel-Ferry)equation is used to analyze the conductivity data,from which the related WLF parameters are determined.