Measurement of a reciprocal four-port transmission line structure using the 16-term error model

A new method to measure reciprocal four-port structures, using a 16-term error model, is presented. The measurement is based on 5 two-port calibration standards connected to two of the ports, while the network analyzer is connected to the two remaining ports. Least-squares-fit data reduction techniques are used to lower error sensitivity. The effect of connectors is deembedded using closed-form equations. (C) 2007 Wiley Periodicals, Inc.

Water-Soluble Graphene Covalently Functionalized by Biocompatible Poly-L-lysine

Graphene sheets functionalized covalently with biocompatible poly-L-lysine (PLL) were first synthesized in all alkaline solution. PLL-functionalized graphene is water-soluble and biocompatible, which makes it a novel material promising for biological applications. Graphene sheets played an important role as connectors to assemble these active amino groups Of Poly-L-lysine, which provided a very biocompatible. environment for further functionalization, such as attaching bioactive molecules. As an example, an amplified biosensor toward H2O2 based on linking peroxidase onto PLL-functionalized graphene was investigated.

Poly-L-lysine functionalization of single-walled carbon nanotubes

Single-walled carbon nanotubes (SWNTs) were covalently functionalized with biocompatible poly-L-lysine, which is useful in promoting cell adhesion. SWNTs played an important role as connectors to assemble these active amino groups of poly-L-lysine, which provided a relative "friendly" and "soft" environment for further derivation, such as attaching bioactive molecules. As an application example, by further linking peroxidase, an amplified biosensing toward H2O2 concerning this assembly was investigated.

Separation of zinc(II) from europium(III) by using hollow fiber membrane

Extraction and separation of Eu3+ and Zn2+ in sulfuric acid solution was investigated by hollow fiber membrane with cyanex 302 (bis (2,4,4-trimethylpentyl) monothiophosphinic acid) in counter-currently circulating operation. Reaction mechanism of membrane extraction and effect of extractant concentration and H+ concentration in aqueous phase on the mass transfer coefficient were discussed. It can be concluded that Zn2+ can be extracted completely from Eu3+ sulfate solution according to the kinetics competing difference. In one extractor process, extraction percentage of Zn2+ was not completely and Eu3+ was not extracted. Extraction percentage of Zn2+ reached 94.92%, but Eu3+ only reached 8.59% after 100 minutes extraction in two series connectors and that of Zn2+ and Eu3+ reached 99.9% and 6.53% respectively after 40 minutes extraction in three series connectors.