Polymer-dispersed liquid crystal films for storing optical holographic images

We have developed an economic liquid crystal-polymer dispersion material that can be used for storing optical holographic images. In this paper, we demonstrate the use of thin samples of this material for such an application. The obtained results show that the written gratings-holograms are permanent, but are electrically switchable. Furthermore, the diffraction efficiency is high and does not change significantly after many tests over a period of months. Thus, we believe this material is promising for practical uses.     

Determination of magnetic susceptibility of various ion-labeled red blood cells by means of analytical magnetapheresis

Analytical magnetapheresis is a newly developed technique for separating magnetically susceptible particles. The magnetically susceptible particles are deposited on a bottom plate after flowing through a thin (< 0.05 cm) separation channel under a magnetic field applied perpendicular to the flow. Particles with various magnetic susceptibilities can be selectively deposited and separated by adjusting the applying magnetic force and flow rates. Magnetic susceptibility is an important parameter for magnetic separation. Magnetic susceptibility determination of various ion-labeled red blood cells (RBCs) using analytical magnetapheresis with a simple theoretical treatment is reported in this study. Susceptibility determination is based on the balance between maximal channel flow rate and magnetically induced flow rate for deposition. We tried a new approach to determine particle magnetic susceptibilities using a balance of magnetic and drag forces to control magnetically induced particle velocities. The Er3+, Fe3+, Cu2+, Mn2+, Co2+, and Ni2+ ions were used to label RBC at various labeling concentrations for susceptibility determination. The susceptibilities determined for various ion-labeled RBC under two magnetic field intensities fell within a 10% range. The average viabilities of various ion-labeled RBCs were 96.1 +/- 0.8%. The susceptibility determination generally took less than 10 min. Determined susceptibilities from analytical magnetapheresis differed by 10% from reference measurements using a superconducting quantum interference device (SQUID) magnetometer. The cost and time for analysis is much less using analytical magnetapheresis. This technique can provide a simple, fast, and economical way for particle susceptibility determinations.     

Analysis of residual phosphorus in poly(p-phenylene benzoxazole), PBO, film by x-ray fluorescence (XRF) spectrometry

Poly(p-phenylene benzoxazole), PBO, is a rigid rod polymer which is polymerized in polyphosphoric acid. Oriented POB film shows good mechanical strength, excellent thermal stability and solvent resistance, and low dielectric constant. The measurement of residual phosphorus in the film is necessary since residual phosphorus may impact the physical and electrical properties of the film. A rapid and non-destructive XRF method has been developed for the analysis of residual phosphorus content in PBO thin films (0.1–2 mil). The XRF method demonstrated good linearity over the range of 150–4100 ppm, with a detection limit of ca 40 ppm. The residual phosphorus in several PBO thin film samples was also measured using NMR spectroscopy, and excellent agreement with the XRF analysis was obtained.     

Rate study of reduction of 2-heptanone with samarium iodide by gas chromatography

This article describes a newly developed method of gas chromatography (GC) for the rate study of the reduction of organic compounds by samarium iodide. Solvent extraction was used to reduce the interference of GC analysis by inorganic species. Adequate recoveries ranged from 88.3 to 94.5 % and good linearity ranging from 0.1 to 2.1 mM was determined. An internal standard, decane, was used to enhance the precision of this test. The coefficient variations of intra-day and inter-day ranged from 0.22 to 3.00%. The stability of the reacted sample was also assessed. In addition, the reaction rates of the reduction of 2-heptanone by samarium iodide in the presence of hexamethylphosphoramide were examined. The results presented hererin demonstrate the utility of this method in kinetic studies.     

Recovery and Reduction of Spent Nickel Oxide Catalyst via Plasma Sintering Technique

A thermal plasma process for the recovery and reduction of nickel oxide in the spent nickel-based catalyst (NiO/SiO₂) was developed. The spent catalyst was sintered at >1,500 °C under plasma condition and the nickel oxide therein was reduced to nickel, which was proven by XRD and EDX. By application of SEM and GC technique, the organic tar on the surface of the spent catalyst was found to decomposed and converted to syngas (CO, CO₂, and H₂), which might be the reducing agents in the process. A gasification mechanism for the generation of syngas and the reduction of nickel oxide under plasma conditions was proposed.     

Novel Vilsmeier-type methylenation for synthesis of dipyrazolylmethane derivatives using formamide or N-methylformamide

A novel Vilsmeier-type methylenation for synthesis of dipyrazolylmethanes was developed by reacting pyrazolones with formamide or N-methylformamide in the presence of phosphorous oxychloride POCl₃ coupling agent. This method can efficiently provide a series of dipyrazolylmethane derivatives as the main products in excellent yields without the formylated products. Our experimental result was different with the classical Vilsmeier-type reaction.     

A novel one-pot synthesis of 2-arylpyrazoloquinolinone derivatives

Two regioisomers of 2-arylpyrazolo[3,4-c]quinolin-4(5H)-ones and 2-arylpyrazolo[4,3-c]quinolin-4(5H)-ones were synthesized by utilizing 3-arylsydnones, ethyl 3-bromopropynoate, and 2-aminophenylboronic acid pinacol ester in presence of catalytic agent Pd(PPh₃)₄. This efficient one-pot synthesis methodology involved 1,3-dipolar cycloaddition, Suzuki coupling reaction, and intramolecular cyclization three sequence steps.     

Synthesis and characterization of new blue‐greenish electroluminescent materials based on 1,3,4‐oxadiazole‐triazolopyridinone hybrids

New functionalized oxadiazole‐triazolopyridinone derivatives were synthesized via arcycloaddition. With the chromophores of triazolopyridinone, the photoluminescence spectra of these compounds in dichloromethane solution showed emission peaks between 430 and 520 nm. Following the spectroscopic studies, and the measurements of cyclic voltammogram, 1,3,4‐oxadiazole‐triazolopyridinone hybrids possess a great potential as highly efficient, blue‐greenish, organic light‐emitting devices materials. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:212–219, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20285     

Optimization for detection of flunarizine by high performance liquid chromatography/electrospray/mass spectrometry

This paper describes a newly developed high performance liquid chromatography/electrospray/mass spectrometry (HPLC/ES/MS) method for the determination of flunarizine (FZ) in artificial cerebrospinal fluid. The optimization for the detection of FZ in biological fluid by LC/ES/MS was investigated. The effects of solvent composition, the addition of modifier and flow rate on the detection of FZ by ES/MS were examined. The detection limit of this method (0.8 nM) proved to be much better than previously reported methods. Satisfactory accuracy (98.2–106.0%) of this newly developed method was obtained. The application of this method was demonstrated by analyzing FZ in rat microdialysis samples.