Real-time ellipsometric characterization of the initial growth stage of poly(3,4-ethylene dioxythiophene): poly(styrene sulfonic acid) films by electrospray deposition

Kinetic spectroscopic ellipsometry have been used to study the initial growth stage of poly(3,4-polyethylene dioxythiophene):poly(styrenesulfonic acid)(PEDOT:PSS) films by the electrospray deposition (ESD) method. The real-time spectra analysis revealed that the surface overlayer decreased in thickness once the first bulk layer monolayer was formed, indicating a smoothening effect as the nucleation-related microstructure coalesced into the bulk layer. Once the coalescence was completed and the nucleation-induced surface roughness layer was stabilized, the underlying bulk layer increased linearly with time. These results originate from the degrees of the evaporation of solvent material during the transferring the precursors to the surface and/or of the diffusion of deposition precursors after sticking at the growing surface.     

Photoelectrochemical and photocatalytic properties of biphasic organic p- and n-type semiconductor nanoparticles fabricated by a reprecipitation process

The visible-light-responsive photoelectrochemical and photocatalytic properties of nanoparticles of C(60), partially hydrolyzed aluminum phthalocyanine chloride (denoted as AlPc), and a composite of the two are reported. The three types of nanoparticles were obtained through a reprecipitation method from N-methyl-2-pyrrolidone solutions of C(60), aluminum phthalocyanine chloride (AlPcCl), and their mixture, respectively. The nanoparticle composite's ultraviolet-visible absorption, diffuse-reflectance and Fourier transform IR spectra, X-ray diffraction pattern, and scanning electron microscopy image are all similar to the sum of those of the C(60) and AlPc particles, respectively. The nano-ordered composite exhibits p/n junctionlike photoelectrochemical characteristics, which were investigated in comparison with those of vapor-deposited C(60) (n-type), AlPcCl (p-type), C(60)/AlPcCl (n/p), and AlPcCl/C(60) (p/n) electrodes. The nanoparticle composite further shows photocatalytic activity for the decomposition of trimethylamine to carbon dioxide in a suspension system.     

A low flicker noise direct conversion receiver for IEEE 802.11g wireless LAN using differential active inductor

In this paper, a low flicker-noise, 2.4 GHz direct onversion receiver (DCR) has been designed. A dynamic current injection (DCI) technique has been utilized in addition with a tuning inductor in the mixing stage. The tuning inductor has been replaced by a differential active inductor circuit, which gives the same inductance, with less chip size and high quality factor. The DCR has been designed in a TSMC 0.18 μm 1P6M CMOS process for wireless LAN 802.11g applications. The proposed DCR achieves 6.7 dB SSB-NF, 34 dB conversion gain, −13.5 dBm IIP3, and flicker noise (1/f) corner frequency of 30 kHz with 137.5 mW power consumption from 1.8 V supply voltage.     

Temperature Dependence of Flexural Strength of a CF-SMC Composite

This paper presents the temperature dependence of predicting the flexural strength of a carbon fiber-reinforced sheet molding compound (CF-SMC). First, three-point flexural tests were performed to measure strength and elastic modulus at a variety of temperatures for CF-SMC specimens. Next, simple equations for predicting flexural strength were derived based on the fracture mechanics approach. The predicted flexural strength was in reasonably good agreement with the experiment results. The scatter of flexural strength was ascribed to the variation of location and size of the initial damage. In addition, the effect of temperature on flexural strength and delamination behavior was explained in association with the temperature dependence of the elastic modulus and fracture toughness.     

A Rapid and Simple Method for the Determination of 2-Alkylcyclobutanones in Irradiated Meat and Processed Foods

A rapid and simple method has been developed for the determination of 2-alkylcyclobutanone, 2-dodecylcyclobutanone (DCB), and 2-tetradecylcyclobutanone (TCB) in irradiated meat and processed foods. The procedure consists of extraction with n-hexane, following defatting and cleanup with a silica gel mini-column before gas chromatograph–mass spectrometry analysis. The method was evaluated using samples of beef, pork, Parmesan cheese, fried chicken, hamburger, gyoza (Chinese dumplings), and gyudon (boiled beef and onion seasoned with soy sauce and sugar). The recoveries of spiked DCB were 67–88 %, and those of TCB were 70–86 %. Furthermore, the method could detect DCB and TCB from samples irradiated at 1.0 and 2.6 kGy at levels dependent on dose; DCB and TCB were not detected in any nonirradiated samples. The method did not require special equipment, such as Soxhlet extraction, accelerated solvent extraction, or supercritical fluid extraction, for sample preparation. Thus, this method would be useful for determining DCB and TCB levels in irradiated meat and processed foods.     

Deposition of Metal Oxide Films from Metal–EDTA Complexes by Flame Spray Technique

R₂O₃ (R = Y, Eu, Er) metal oxides were synthesized from metal–ethylenediaminetetraacetic acid (EDTA) complexes using a flame spray technique. As this technique enables high deposition rates, films with thickness of several tens of micrometers were obtained. Films of yttria, europia, and erbia phase were synthesized on stainless-steel substrates with reaction assistance by H₂–O₂ combustion gas. The oxide films consisted of the desired crystalline phase with micropores. The porosity of the films was in the range of 6–15%, varying with the metal used. These results suggest that the true density of the metal oxide obtained from metal–EDTA powder through the thermal reaction process plays an important role in achieving film with the desired porosity.     

Fe/C interactions during SWNT growth with C2 feedstock molecules: A quantum chemical molecular dynamics study

We are presenting the first quantum chemical molecular dynamics (QM/MD) model simulations for iron catalyzed single-walled carbon nanotube (SWNT) growth based on the density functional tight binding (DFTB) quantum chemical potential. As model systems, open-ended (10,10) armchair tube fragments were selected with 0, 10, and 20 Fe atoms attached in 1,4-positions on the open rims, and ensembles of randomly oriented C2 molecules were included to simulate carbon plasma feedstock molecules. Isokinetic trajectories at 1500 K to 3000 K show that divalent Fe increases the number of coordination partners with carbon and/or Fe, depending on the Fe concentration. Fe/C interactions weaken the tube sidewall due to electron transfer from Fe into antibonding carbon orbitals, and C2 addition occurs mainly in an Fe-C2-Fe bridge addition mechanism, while growth of polyyne chains characteristic for high-temperature carbon systems is suppressed in the presence of Fe on the rims of the growing SWNT. Our findings are the first quantum chemical evidence for the importance of intermetallic interactions during SWNT growth.     

Clinical applications of the quick-freezing and deep-etching method to human diabetic nephropathy

Mesangial expansion and glomerular basement membrane (GBM) thickening were not different between normoalbuminuric (NA) and microalbuminuric (MA) type 2 diabetic patients. The quick-freezing and deep-etching (QF-DE) method allows us to examine three-dimensional ultrastructures of human renal glomeruli in vivo at high resolution. In the present study, the QF-DE method was applied to the renal biopsy from 6 type 2 diabetic patients without definable renal diseases other than diabetic nephropathy. Four patients were NA and the other two were MA. Three control specimens were normal parts in surgically resected kidneys of renal cell carcinoma. Replica membranes were prepared by the QF-DE method as previously described. By the QF-DE method, both GBM middle layer and mesangial matrix (MM) were composed of polygonal meshwork structures. The mesh pores of GBM and MM were more enlarged in size and irregular in shape in NA diabetic patients than those of the controls, and these ultrastructural changes became more obvious in MA patients. The diameters of mesh pores in the diabetic patients were significantly larger than those in the control subjects. In conclusion, the QF-DE method could be applied to needle renal biopsy and the present study has firstly clarified the difference of ultrastructural changes between NA and MA type 2 diabetic patients, which had not been disclosed by the conventional electron microscopy, were revealed by the QF-DE method.