Influence of nanoparticle size to the electrical properties of naphthalenediimide on single-walled carbon nanotube wiring

Nanoparticles of N,N'-bis(n-alkyl)tetracarbonatenaphthalenediimide (NDI) were adsorbed on single-walled carbon nanotube (SWNT) wires dispersed on a SiO(2) substrate. The electrical properties were measured along the long axis of the SWNTs, and in all cases through the nanoparticles showed rectification in semiconducting I-V curve. The plateau width of the I-V curve through the NDI nanoparticles on metallic SWNTs decreased as the particle size increased, while the rectification ratio increased. The conduction mechanism was changed from tunneling conduction to Schottky-like conduction and their boundary is at about 3 nm diameter.     

Near-infrared imaging of water in a polymer electrolyte membrane during a fuel cell operation

A novel technique of spectroscopic imaging using a near-infrared (NIR) laser sheet beam was developed for visualization of liquid water in a proton-exchange membrane (PEM) sandwiched between two opaque electrodes set in a polymer electrolyte fuel cell (PEFC). In-plane two-dimensional distribution of water in the thin membrane was clearly visualized during the fuel cell operation. Under the condition of fuel feeding into the PEFC without humidification, water was generated by the fuel cell reaction in the whole electrode area. In contrast, under the condition of fuel feeding with humidification, the PEM got wet in the vicinity of a gas flow field locally.     

Distribution parameter and drift velocity for two-phase flow in a large diameter pipe

In view of practical importance of the drift flux model for two-phase flow analysis in general, and in the analysis of nuclear reactor transients and accidents in particular, the distribution parameter, and the drift velocity have been studied for two-phase flow in a vertical large diameter pipe. In this, study, local measurements were performed on flow parameters, such as void fraction, gas velocity and, liquid velocity in a vertical upward air–water two-phase flow in a pipe of 200 mm inner diameter and, 25 m in height by using the local sensor techniques such as hot-film probes, optical multi-sensor, probes and differential pressure gauges. Two-phase flow regimes in a vertical large diameter pipe, were classified into bubbly, churn and slug flows according to the visual observation. The values of the, distribution parameter and the mean drift velocity were determined directly by their definition using experiment data of the local flow parameters in a two-phase flow in a large diameter pipe. Various existing drift flux correlations were compared with the present experimental results and experimental data obtained by other researchers. A detailed discussion on the problems of these correlations was presented in this paper.     

Dietary Tuna Dark Muscle Protein Attenuates Hepatic Steatosis and Increases Serum High‐Density Lipoprotein Cholesterol in Obese Type‐2 Diabetic/Obese KK‐Ay Mice

Tuna muscle consists of light and dark muscle in approximately equal proportions. However, besides for the light muscle of tuna, cod, sardine, and salmon, few researches have assessed the health‐promoting functions of fish protein. Therefore, we evaluated the mechanisms underlying the alteration of lipid storage and cholesterol metabolism following the intake of tuna dark muscle protein (TDMP) by obese type‐2 diabetic/obese mice. Four‐week‐old male KK‐A^y mice were separated into 2 dietary groups, with one group receiving a casein‐based diet and the other receiving a diet with the substitution of part of the protein (50%, w/w) by TDMP (TDMP diet) for 4 wk. The TDMP diet significantly increased the content of serum high‐density lipoprotein cholesterol, partly due to the reduction of the expression of scavenger receptor class B member 1 in epididymal white adipose tissue. In addition, dietary TDMP decreased the content of hepatic triacylglycerol, which could be due to the enhancement of carnitine palmitoyltransferase‐2 activity through the activation of the expression of the peroxisome proliferative activated receptor‐α in the liver. These results suggest that TDMP could have the potential to prevent the development of obesity‐related diseases by suppressing the storage of hepatic triacylglycerol and cholesterol.     

Porcine hemoglobin promotes lipid excretion to feces more strongly than globin protein in rats

In an effort to clarify whether the lipid-lowering effect of hemoglobin is due to globin protein or heme, this study investigated the effects of dietary porcine hemoglobin (PH) and porcine globin (PG) on lipids contents of serum, liver, and feces in rats. Five-week-old male Wistar rats were divided into 3 dietary groups of 7 rats each, with one group receiving a control diet and the other groups receiving diets containing 1.25% (w/w) PH or 1.18% (w/w) PG for 4 weeks. The PH diet decreased triacylglycerol content in serum and cholesterol in serum and liver, whereas the PG diet reduced triacylglycerol content in serum and cholesterol in liver. Fecal lipid excretion in the PH group was significantly higher than in the PG group. Therefore, PH affected lipid excretion to feces due to globin protein as well as heme.     

On the mechanism of intergranular stress corrosion cracking of sensitized stainless steel in tetrathionate solution

Intergranular stress corrosion cracking (SCC) mechanism in sensitized stainless steel (Type 304) was investigated experimentally. A tetra-thionic potassium (K₂S₄O₆) chemical solution was used to mimic polythionic acid SCC which the most aggressive SCC type. During the SCC test, the steel specimen was subjected to three-point bending with constant strain at room temperature, and simultaneous monitoring of acoustic emission and corrosion potential were employed to monitor SCC initiation and progression. At the early stage, transient phenomenon of local anodic dissolution was observed. Upon initiation of SCC, passivation film fracture and dissolution of metal at specimen surface take place. Through microscopic observation of SCC tip, it was found that the SCC tip advanced along the grain boundary with further mechanical loading. This suggested that the stress component plays a significant role of SCC propagation, in addition to the effect of the localized metal dissolution along Cr-depleted grain boundaries.     

Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy

Abstract

As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic–inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH₃NH₃I) and inorganic halide (B-site: PbI₂) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I-V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI₂ and CH₃NH₃I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell.     

Effect of [60] Fullerene on the Chondrogenesis in Mouse Embryonic Limb Bud Cell Culture System

Abstract

[60] Fullerene solubilized with polyvinylpyrrolidone (PVP) promoted the mouse embryonic limb bud cell differentiation specifically. The cell lysis caused by C60 was diminished by the addition of superoxide dismutase and catalase.     

The alkylation of biphenyl over three-dimensional large pore zeolites: The influence of zeolite structure and alkylating agent on the selectivity for 4,4′-dialkylbiphenyl

Catalytic properties of three-dimensional zeolites, Y (FAU), Beta (BEA), and CIT-1 (CON) zeolites were examined in the alkylation, isopropylation, sec-butylation, and tert-butylation, of biphenyl (BP), and compared to those of H-mordenite (MOR). The selectivities for 4,4′-dialkylbiphenyl (4,4′-DABP) varied with the types of zeolite and of alkylating agent. FAU, BEA, and CON gave only low selectivities for 4,4′-diisopropylbiphenyl (4,4′-DIPB) in the isopropylation, and predominant isomers were bulky and thermodynamically unstable 2,x′-DIPB (2,2′-, 2,3′-, and 2,4′-) at lower temperatures, and bulky and thermodynamically stable 3,4′- and 3,3′-DIPB at higher temperatures: this is quite different from catalytic features over MOR, which gave 4,4′-DIPB with high selectivities at moderate temperatures. These results suggest that FAU, BEA, and CON have no shape-selective nature in the isopropylation, and that the reaction is principally controlled kinetically at lower temperatures, and thermodynamically at higher temperatures. The sec-butylation gave similar results to the isopropylation. Although the selectivities for 4,4′-di-sec-butylbiphenyl (4,4′-DSBB) were higher than those in the isopropylation, predominant isomers were 2,x′-DSBB (2,2′-, 2,3′-, and 2,4′-) at lower temperatures, and 3,4′- and 3,3′-DSBB at higher temperatures. The tert-butylation gave 4,4′-di-tert-butylbiphenyl (4,4′-DTBB) in moderate to high selectivities over all zeolites at moderate temperatures: the selectivity for 4,4′-DTBB was higher than 80% over BEA and CON; however, it still remained at 50% over FAU. FAU channels with super cages are too large for selective formation of 4,4′-DTBB.

From these results, it is concluded that the selectivity for 4,4′-DABP in the alkylation over MOR, FAU, BEA, and CON is determined by the exclusion of bulky isomers at their transition states, and that the exclusion is caused by the steric restriction at the transition states of bulky isomers by the zeolite channels.