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41.
To clarify the mechanism of salt fretting of a brick building, monthly observations were made over one year at a two-storey brick kiln in central Japan. Products of weathering that had fallen were collected and weighed; salts were identified using XRD and the moisture content of the brick was measured at its surface using a portable infrared optical moisture meter. Gypsum (CaSO4·2H2O) was found at the bottom of the first floor wall in the warm and humid season. Thenardite (Na2SO4) is dominant on the first floor wall; it is abundant in the cold and dry season but sparse in the warm and humid season. Magnesium sulphate is dominant on the second floor wall; epsomite (MgSO4·7H2O) was observed in the dry-to-wet season and hexahydrite (MgSO4·6H2O) in the wet-to-dry season. Seasonal changes in salt abundance result from the temperature dependence of the solubilities and equilibrium relative humidities (ERH) of each salt. The amount of brick decay material due to salt weathering is much greater from the second floor wall than from the first floor wall and is greater from spring to the end of summer. These seasonal and spatial variations of the rate of brick decay can be explained by a combination of factors: (1) the types of salt, (2) efflorescence or sub-florescence and (3) salt deliquescence.  相似文献   
42.
Micro-tensile tests were performed on high-pressure-torsion-processed specimens of type 304 steel with grain sizes in the range of 0.1–0.5 μm to clarify the effect of ultrafine grain refinement on the hydrogen embrittlement (HE) of metastable austenitic steel. The ultrafine-grained (UFG) specimens with average grain sizes < ~0.4 μm exhibited a limited uniform elongation followed by a steady-stress regime in the stress–strain curves, which was attributed to a martensitic transformation. A high yield stress and a moderate elongation to failure were attained for the UFG specimens with an average grain size of ~0.5 μm in the uncharged state. Hall–Petch relationships well hold between the yield stress and the average grain size for each uncharged and hydrogen-charged specimen. Hydrogen charging increased the friction stress by 40% but did not change the Hall–Petch coefficient. Hydrogen-induced ductility loss was mitigated by ultrafine grain refinement. Ductility loss due to hydrogen charging manifested in the local deformation after a martensitic transformation. This indicates that hydrogen does not significantly affect the martensitic transformation, but shortens the subsequent local deformation process.  相似文献   
43.
We have developed a three-dimensional clothed human thermal model for predicting physiological responses to temperature and humidity within clothing by considering the thermal properties of fabrics, clothing ensembles, and their designs. The model is a coupled simulation system of a human thermal model and a clothing thermal model. The model performance was investigated by comparing its predictions with experimental data. The following results were obtained. (1) The model predictions of skin temperature distributions and the micro-climate within clothing basically agreed with experimental data. (2) The skin temperatures of clothed body parts were higher than the corresponding body parts in the nude condition, and the skin temperatures of the hand and foot were higher than those in the nude condition, both in the model predictions and in the experimental data. (3) The model prediction of total moisture transfer was almost the same as obtained from the experimental data. 1998 Scripta Technica, Heat Trans Jpn Res, 26(8): 554–566, 1997  相似文献   
44.
We performed X-ray diffraction analyses on rat plantaris muscle to determine if there are strain-specific structural changes at the molecular level after eccentric contraction (ECC). ECC was elicited in situ by supramaximal electrical stimulation through the tibial nerve. One hour after a series of ECC sessions, the structural changes that remained in the sarcomere were evaluated using X-ray diffraction. Proteins involved in cell signaling pathways in the muscle were also examined. ECC elicited by 100, 75, and 50 Hz stimulation respectively developed peak tension of 1.34, 1.12 and 0.79 times the isometric maximal tetanus tension. The series of ECC sessions phosphorylated the forkhead box O proteins (FoxO) in a tension-time integral-dependent manner, as well as phosphorylated the mitogen-activated protein kinases (MAPK) and a protein in the mammalian target of rapamycin (mTOR) pathway in a maximal tension dependent manner. Compared to isometric contractions, ECC was more efficient in phosphorylating the signaling proteins. X-ray diffraction revealed that the myofilament lattice was preserved even after intense ECC stimulation at 100 Hz. Additionally, ECC < 75 Hz preserved the molecular alignment of myoproteins along the myofilaments, while 75-Hz stimulation induced a slight but significant decrease in the intensity of meridional troponin reflection at 1/38 nm−1, and of myosin reflection at 1/14.4 nm−1. These two reflections demonstrated no appreciable decrease with triple repetitions of the standard series of ECC sessions at 50 Hz, suggesting that the intensity decrease depended on the instantaneous maximal tension development rather than the total load of contraction, and was more likely linked with the phosphorylation of MAPK and mTOR signaling proteins.  相似文献   
45.
The paper presents a quantitative approach to the investigation and comparison of the material qualities of III–V on silicon (III–V/Si) solar cells by using external radiative efficiencies. We use this analysis to predict the limiting efficiencies and evaluate the criteria of material quality in order to achieve high‐efficiency III–V/Si solar cells. This result yields several implications for the design of high‐efficiency III–V/Si solar cells. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
46.
A micro gas chromatography (µGC) instrument applying a high performance chip column fabricated on a silicon wafer was developed. Experimental results of the chip column and protyping of a µGC instrument are described. Approximately 35 000 theoretical plates were generated with the chip column coated liquid phase (5% phenyl-/95% dimethyl-polysiloxane). The theoretical plates of the chip column were close to those of the capillary column. Experimental minimum height equivalent to a theoretical plate (HETP, Hmin) of the chip column was 1.2 times higher than the calculated Hmin. A prototype µGC applying the chip column was developed. The µGC generated approximately 35 000 theoretical plates, similar to the theoretical plates obtained by a commercial GC instrument. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  相似文献   
47.
The carbohydrate esterase family 1 (CE1) in CAZy contains acetylxylan esterases (AXEs) and feruloyl esterases (FAEs). Here we cloned a gene coding for an AXE belonging to CE1 from Irpex lacteus (IlAXE1). IlAXE1 was heterologously expressed in Pichia pastoris, and the recombinant enzyme was purified and characterized. IlAXE1 hydrolyzed p-nitrophenyl acetate, α-naphthyl acetate and 4-methylumbelliferyl acetate, however, it did not show any activity on ethyl ferulate and methyl p-coumarate. We also examined the activity on partially acetylated and feruloylated xylan extracted from corncob by hydrothermal reaction. Similarly, ferulic and p-coumaric acids were not liberated, and acetic acid was only detected in the reaction mixture. The results indicated that IlAXE1 is an acetylxylan esterase actually reacted to acetyl xylan. However, since IlAXE1 was unable to completely release acetic acid esterifying xylopyranosyl residues, it is assumed that acetyl groups exhibiting resistance to deacetylation by IlAXE1 are present in corn cob xylan.  相似文献   
48.
Thin films of microcrystalline (CnH2n + 1NH3)2PbBr4 (n = 4, 5, 7 and 12) have been prepared by a modified spin-coating method, and the effect of the number of carbon atoms of the alkyl chain length (n) on optical properties has been investigated. Absorption spectra reveal that (CnH2n + 1NH3)2PbBr4 films show stable excitons with a binding energy of a few hundred meV. The excitonic structure of (CnH2n + 1NH3)2PbBr4 varies with the number of carbon atoms. The lowest-energy exciton splits into a few fine-structure levels at low temperature. (CnH2n + 1NH3)2PbBr4 films (n = 5, 7 and 12) show not only singlet excitons but also triplet excitons at low temperature, while (C4H9NH3)2PbBr4 films show only singlet excitons. The intersystem crossing from excited singlet state to triplet state plays an important role in the relaxation process of excitons.  相似文献   
49.
Transition metal-catalyzed cross-coupling reactions of organic halides and pseudo-halides containing a C-X bond (X = I, Br, Cl, OTf, OTs, etc.) with organometallic reagents are among the most important transformations for carbon-carbon bond formation between a variety of sp, sp(2), and sp(3)-hybridized carbon atoms. In particular, researchers have widely employed Ni- and Pd-catalyzed cross-coupling to synthesize complex organic structures from readily available components. The catalytic cycle of this process comprises oxidative addition, transmetalation, and reductive elimination steps. In these reactions, various organometallic reagents could bear a variety of R groups (alkyl, vinyl, aryl, or allyl), but the coupling partner has been primarily limited to sp and sp(2) carbon compounds: alkynes, alkenes, and arenes. With alkyl coupling partners, these reactions typically run into two problems within the catalytic cycle. First, oxidative addition of alkyl halides to a metal catalyst is generally less efficient than that of aryl or alkenyl compounds. Second, the alkylmetal intermediates formed tend to undergo intramolecular beta-hydrogen elimination. In this Account, we describe our efforts to overcome these problems for Ni and Pd chemistry. We have developed new catalytic systems that do not involve M(0) species but proceed via an anionic complex as the key intermediate. For example, we developed a unique cross-coupling reaction of alkyl halides with organomagnesium or organozinc reagents catalyzed by using a 1,3-butadiene as the additive. This reaction follows a new catalytic pathway: the Ni or Pd catalyst reacts first with R-MgX to form an anionic complex, which then reacts with alkyl halides. Bis-dienes were also effective additives for the Ni-catalyzed cross-coupling reaction of organozinc reagents with alkyl halides. This catalytic system tolerates a wide variety of functional groups, including nitriles, ketones, amides, and esters. In addition, we have extended the utility of Cu-catalyzed cross-coupling reactions. With 1-phenylpropyne as an additive, Cu-catalyzed reactions of alkyl chlorides, fluorides, and mesylates with Grignard reagents proceed efficiently. These new catalytic reactions use pi-carbon ligands such as pi-allyl units or alkynes instead of heteroatom ligands such as phosphines or amines. Overall, these reactions provide new methodology for introducing alkyl moieties into organic molecules.  相似文献   
50.
The stock of aged power equipment is increasing and it is important to clarify the characteristics of deteriorated insulating oil. This paper describes a basic study of molecular behavior in the oxidation of insulating oil by terahertz spectroscopy. The oxidation of insulating oil was modeled by using various compositions of dodecane and 2‐octanol. The terahertz measurements indicated that signi?cant absorption related to hydroxyl groups (‐OH) occurred between 6 and 7 THz. The absorption band was also observed in accelerated aging alkylbenzene, which is used in power equipment as insulating oil and is sensitive to hydrogen bonds. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 9–15, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22335  相似文献   
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