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961.
962.
Longitudinal and transverse wave velocities, eight kinds of elastic parameters, and dilational and shear internal frictions of Zr55Cu30Al10Ni5 glassy alloy were simultaneously measured as a function of temperature in the range from 77 to 373 K, using an ultrasonic pulse method. The inflections at around 150 K for wave velocities, anisotropy factor and Poisson's ratio, and the 150 K peak of shear friction seem to correspond to one topological change (pseudo‐transition) associated with an interatomic readjustment or vacancy rearrangements. The behaviors from 77 to 125 K and 125 to 373 K are due to thermal relaxation of squeezed free volumes and entropy elasticity associated with vibrational motions of clusters, respectively, accompanied by an increase in atomic distance. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
963.
Chemical and Toxicological Investigations of a Previously Unknown Poisonous European Mushroom Tricholoma terreum 下载免费PDF全文
Xia Yin Dr. Tao Feng Prof. Jian‐Hua Shang Yun‐Li Zhao Fang Wang Zheng‐Hui Li Ze‐Jun Dong Prof. Dr. Xiao‐Dong Luo Prof. Dr. Ji‐Kai Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(23):7001-7009
The established tradition of consuming and marketing wild mushrooms has focused attention on mycotoxicity, which has become a global issue. In the present study, we describe the toxins found in a previously unknown poisonous European mushroom Tricholoma terreum. Fifteen new triterpenoids terreolides A–F ( 1 – 6 ) and saponaceolides H–P ( 8 – 16 ) were isolated from the fruiting bodies of the toxic mushroom T. terreum. Terreolides A–C ( 1 – 3 ) possessed a unique 5/6/7 trioxaspiroketal system, whereas terreolides D–F ( 4 – 6 ) possessed an unprecedented carbon skeleton. Two abundant compounds in the mushroom, saponaceolide B ( 7 ) and saponaceolide M ( 13 ), displayed acute toxicity, with LD50 values of 88.3 and 63.7 mg kg?1 when administered orally in mice. Both compounds were found to increase serum creatine kinase levels in mice, indicating that T. terreum may be the cause of mushroom poisoning ultimately leading to rhabdomyolysis. 相似文献
964.
Z. F. Yin Y. R. Feng W. Z. Zhao Z. Q. Bai G. F. Lin 《Surface and interface analysis : SIA》2009,41(6):517-523
This work investigates the effect of temperature on the corrosion product layer of carbon steel exposed to a CO2‐containing solution. The measurement techniques, such as scanning electron microscopy with energy dispersive spectrometry, X‐ray diffraction, and X‐ray photoelectron spectroscopy, were used to systematically characterize the morphology and composition of the corrosion product layer. The corrosion rates were calculated by weight loss method. The corrosion mechanisms as a function of temperature are studied and discussed. The results showed that temperature is an important factor in the corrosion rate of carbon steel. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
965.
Three new complexes with the ligand 3,5‐diamino‐1,2,4‐triazole (Hdatrz), [Co3(μ2‐Hdatrz)6(H2O)6]·(NO3)8·4H2O ( 1 ), [Cu3(μ2‐Hdatrz)4(μ2‐Cl)2(H2O)2Cl2]·Cl2·4H2O·2C2H5OH ( 2 ) and {[Zn2(μ2‐SO4) (μ3‐datrz)2]·2H2O}n ( 3 ) have been synthesized and structurally characterized. Complex 1 has a linear trinuclear mixed‐valence cobalt structure with six neutral triazole ligands in the N(1), N(2)‐bridging mode. The central cobalt atom, Co(1), is coordinated to six nitrogen atoms (octahedral) whereas the terminal cobalt atom, Co(2), is coordinated to an N3O3 moiety (octahedral). In complex 1 , the uudd cyclic water clusters, nitrate anions and the trimeric cations are linked to a supramolecular structure. Complex 2 features a linear trinuclear copper(II) core, with four N(1), N(2)‐bridging triazole ligands and two chlorido bridges. The central copper atom is coordinated to an N4Cl2 moiety (octahedral) whereas the terminal copper is coordinated to an N2Cl2O moiety (square‐pyramidal). In complex 2 , tetrahedral hydrogen bonding interactions play an important role to form a supramolecular network. Complex 3 exhibits a polymeric structure, with N(1), N(2), N(4)‐bridging triazolate ligands and sulfate bridges, in which zinc is coordinated to an N3O moiety (tetrahedral). In complex 3 , water molecules and sulfate anions construct the sulfate‐water supramolecular chain with hydrogen bonding interactions. In addition, the complexes were investigated by elemental analyses, IR spectroscopic, and thermogravimetric measurements. 相似文献
966.
以8-羟基喹啉和乙酸铜为主要原料,通过简单调控醇水介质和熟化时间,液相沉淀法快速合成出大量不同形貌和晶型的8-羟基喹啉铜微纳米材料.采用SEM,XRD,UV-Vis,FT-IR对产物进行表征.结果表明,以8-羟基喹啉盐酸水溶液与乙酸铜水溶液反应,合成了直径40~130nm的棒状α型二水合8-羟基喹啉铜沉淀物.以8-羟基喹啉乙醇溶液与乙酸铜乙醇溶液反应,获得了厚度约300nm的三维(3D)板条束状α型无水8-羟基喹啉铜微纳米结构.若采用8-羟基喹啉乙醇溶液与乙酸铜的乙醇/水溶液反应,当体系醇/水体积比为3∶1时,随着熟化时间的延长,产物由亚稳的α型和γ型晶相向稳定的β型晶相转变,形貌从胡须束状/菱片状混合结构转变为纳米棒状/菱片状混合结构,50min熟化后最终形成菱片状β型二水合8-羟基喹啉铜及其四角星形自组装体. 相似文献
967.
Four cubane-like Cu4I4 units are assembled around an iodine atom to form the giant, mixed-valent Cu(II)Cu(I)15I17 cluster. The Cu(II)Cu(I)15I17 cluster and a bipyrazole linker form a 3D open framework with paramagnetic and thermochromic properties. This paper also touches on the resemblance of this cluster to the self-similar object of a Sierpinski tetrahedron. 相似文献
968.
969.
970.
Immobilization of silver nanoparticles into POEGMA polymer brushes as SERS‐active substrates 下载免费PDF全文
Qian Zhang Jun‐Jiao Yin Feng Liu Xue‐Na Zou Li‐Qiang Chu 《Surface and interface analysis : SIA》2017,49(4):316-322
Surface‐enhanced Raman scattering (SERS) has attracted a great deal of interest during the past four decades and emerged as an ultrasensitive optical technique for chemical and biomedical analysis. It is widely accepted that the facile fabrication of SERS substrates with high activity and good reproducibility is of crucial importance for their applications. Herein, we report on a fast and robust method for the synthesis and immobilization of silver nanoparticles (AgNPs) into poly(oligo(ethylene glycol) methacrylate) (POEGMA) brushes under mild conditions without using any reducing agents. POEGMA brushes of different chain lengths were synthesized directly on silicon wafers by surface‐initiated atom transfer radical polymerization with various reaction time. X‐ray photoelectron spectroscopy and field emission scanning electron microscope measurements indicated that the AgNPs were firmly and homogeneously embedded into POEGMA brushes. The resulting POEGMA–AgNP hybrid films were employed as SERS substrates for the detection of 4‐aminothiophenol, giving rise to an enhancement factor of up to 1.9 × 106. The influence of the POEGMA's chain length on SERS performance was also investigated. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献