Interfacial electrostatic phenomena and capacitance–voltage characteristics of ultrathin polyimide Langmuir–Blodgett films

Capacitance–voltage (C–V) characteristic of ultrathin polyimide (PI) Langmuir–Blodgett (LB) films is discussed theoretically and experimentally taking into account the interfacial electrostatic phenomena and interfacial electronic states at the metal/PI LB film interface. It was found that the apparent film thickness decreases due to the charge exchange phenomena at the metal/film interface. It was also found that electrical insulating properties of the Au/PI LB film/Al device depended on the polarity of external voltage, probably due to the formation of the electrostatic interfacial electric field of 10⁸ to 10⁹ V/m. © 2000 Scripta Technica, Electr Eng Jpn 134(3): 9–15, 2001     

Effect of poly(vinyl acetate/vinyl alcohol) copolymer with a thiol end group as a steric stabilizer on dispersion polymerization of styrene

In dispersion polymerization of styrene in ethanol, effects of a reactive steric stabilizer, poly(vinyl acetate/vinyl alcohol) copolymer with a thiol end group (P(VAc/VA)-SH), were investigated. In the absence of the thiol end group, the dispersion coagulated at the middle stage of the polymerization, while in the presence of the thiol end group, the polymerization proceeded successfully to result in close to monodisperse particles. The reactive thiol group acts as a site of formation of the block copolymer, that is, polystyrene-b-P(VAc/VA), which is utilized as an effective dispersant. From the measurement on molecular weights during the course of polymerization, two polymerization loci were realized. Addition of butyl methacrylate to styrene affected markedly not only rate of polymerization but also particle size. © 1996 John Wiley & Sons, Inc.     

Properties and substrate specificities of proteolytic enzymes from the edible basidiomycete Grifola frondosa

Highly active proteolytic enzymes are found in the fruiting bodies of Grifola frondosa. The general properties and substrate specificities of these proteases from G. frondosa (ProGF) were studied. The optimal pH for ProGF activity was pH 3 or 7 using hemoglobin or Hammersten casein as a substrate, respectively. The ProGF exhibited over 70% of maximal activity within the pH range of 4.5–8.5. In terms of temperature, the ProGF were maximally active at 55 °C, while over 80% of maximal activity was observed within the range of 50–75 °C. These proteases were substrate-specific, mainly cleaving at Ala¹⁴-Leu¹⁵, Tyr¹⁶-Leu¹⁷, and Pro²⁸-Lys²⁹ bonds, with occasional cleavage of Phe²⁴-Phe²⁵ bonds in the oxidized insulin B-chain. The ProGF also liberated hydrophobic amino acids, such as valine, leucine, and phenylalanine, using the oxidized insulin B-chain as a substrate. When soy protein was used as a substrate, valine, leucine, phenylalanine, and tyrosine were selectively released from the hydrolysate. Thus, over the time course of incubation, the peptide concentration increased as the average peptide chain length decreased. These results indicate that the ProGF include both endopeptidases recognizing leucine, phenylalanine, and lysine at the P1′ position, and aminopeptidases preferentially releasing hydrophobic and aromatic amino acids such as valine, leucine, phenylalanine, and tyrosine.     

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.     

A numerical investigation of evaporation characteristics of a fuel droplet suspended from a thermocouple

Numerical simulations of combined natural convection–conduction in a droplet of n-dodecane suspended from a thermocouple were carried out, taking into consideration evaporation, and the effect of thermocouple diameter on the evaporation characteristics was investigated. The calculated temperature history of the droplet is in good agreement with experimental results; both show that the rate of heating decreases with increasing thermocouple diameter. The maximum error in temperature due to the thermocouple increases linearly with increasing thermocouple diameter. Thus, in investigations involving a droplet suspended from a thermocouple, it is preferable to use a thermocouple with the smallest possible diameter.     

高炉操作对炉缸侵蚀的影响

 沙钢宏发炼铁厂1号高炉因炉缸侵蚀于2011年1月进行大修。炉缸内第6、7层碳砖侵蚀最严重,呈异常三角形侵蚀。通过对炉缸碳砖的分析和操作条件的模拟,发现高炉锌负荷过高和铁水环流是加剧炉缸侵蚀的主要原因。宏发高炉的锌负荷偏高,使ZnO在炉缸第6、7层碳砖中严重富集,导致碳砖导热系数下降,热膨胀系数增加,加剧碳砖的熔蚀和热应力引起的侵蚀。另外,由于原料质量和操作原因,使得宏发高炉的铁口长度较短、无焦区偏小和死料柱的透气透液性有时较差,加剧了铁水环流对炉缸的侵蚀。可以通过控制入炉锌负荷,延长铁口长度、控制死料柱的尺寸、提高焦炭质量和控制合适的喷煤比来改善炉缸的侵蚀。     

Three-dimensional time-averaged void fraction distribution measurement technique for BWR thermal hydraulic conditions using an X-ray CT system

We have developed a void fraction distribution measurement technique using the three-dimensional (3D) time-averaged X-ray computed tomography (CT) system to understand two-phase flow behavior inside a fuel bundle for boiling water reactor (BWR) thermal hydraulic conditions of 7.2 MPa and 288 °C. As a first step, we measured the 3D void fraction distribution in a vertical square (5?×?5) rod array that simulated a BWR fuel bundle in the air–water test. A comparison of the volume-averaged void fractions evaluated by the developed X-ray CT system with those evaluated by a differential pressure transducer showed satisfactory agreement within a difference of 0.03. Thus, we confirmed that the developed system could be used to get 3D imaging of the vertical square rod array used in the test under the BWR operating pressure condition. In the next step, we did a verification test using the vertical pipe (11.3 mm ID) for BWR thermal hydraulic conditions. A comparison of the cross-sectional-averaged void fractions evaluated by the X-ray CT system with those evaluated by the drift-flux model showed good agreement within a difference of 0.05. We confirmed that the evaluated void fraction distribution forms in the horizontal cross section changed with the quality in response to the flow regime transition.     

EXAFS Study on Structural Change of Charcoal-supported Ruthenium Catalysts during Lignin Gasification in Supercritical Water

Lignin gasification in supercritical water over charcoal supported ruthenium trivalent salts was studied using a batch reactor at 673 K. Ruthenium (III) nitrosyl nitrate on charcoal (Ru(NO)(NO₃)₃/C) was more active than ruthenium (III) chloride on charcoal (RuCl₃/C) for the gasification reaction. EXAFS analysis revealed that ruthenium metal particles were formed in both RuCl₃/C and Ru(NO)(NO₃)₃/C catalysts during the lignin gasification and that the size of ruthenium metal in Ru(NO)(NO₃)₃/C was smaller than that in RuCl₃/C. It was concluded that well-dispersed ruthenium metal particles were active for the lignin gasification in supercritical water.     

梼原町综合大会堂

原镇位于高知县内,因为其城市的发展被冠以"日本的香柏"而闻名,这个镇因为其与"木头城礼堂"具有一样的文化背景而有了新的开始,这是在日本最大尺寸的"木质"镇礼堂。考虑到下雪的天气情况,该建筑设立了一个大中庭,而建立的室内广场为市民提供了日常生活中的银行、农业合作社、商会等设施。这个大庭同时也是传统表演和节日的场所。