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101.
102.
T. Katsumata H. Okada T. Kikuta T. Fukuda 《Applied Physics A: Materials Science & Processing》1987,42(2):103-109
The wavelength dependence and polarization characteristics of the infrared light scattered from an undoped GaAs crystal were investigated in the 90° angle infrared light scattering configuration. The scattering is Rayleigh scattering from scatterers which are always associated with the dislocations, and they are classified into three types,S, L
A
, andL
G
scatterers, according to their polarization characteristics. TheS, L
A
, andL
G
-scatterers are thought to be small As clusters, large As precipitates and large Ga precipitates, respectively. 相似文献
103.
Akira Tanaka Mitsuhiro Fukuda Hiroyuki Nagai Masayuki Shinohara Shigeharu Onogi 《Journal of Polymer Science.Polymer Physics》1989,27(11):2283-2293
A new apparatus was designed to investigate the dynamic viscoelastic properties of solid polymer materials in the nonlinear viscoelastic region. The apparatus was combined with a birefringence apparatus in such a way that birefringence could be measured simultaneously with stress under oscillatory deformation. The nonlinear viscoelastic behavior of bulk-crystallized high-density polyethylene films was examined. Nonlinearity of mechanical properties became evident around 30°C, while optical properties became markedly nonlinear around 50°C. The nonlinearity of viscoelastic properties changes very little when the films are swollen with tetrachloroethane. It is proposed that disruption of lamellae to crystallites in the drawing process is one of the most important causes of the nonlinear behavior of high-density polyethylene films. 相似文献
104.
105.
Hiroki Hotta Kazuya Tatsuno Yoji Hattori Takuya Hashimoto Masayuki Uehara Kin-ichi Tsunoda 《Electrochemistry communications》2008,10(9):1351-1354
The H+ concentration change was monitored near an electrode surface through an electrolysis using a slab optical waveguide technique. Indium tin oxide transparent electrode modified by porous insulating polymer to which methyl red was covalently immobilized was used as a guiding layer, and the absorbance change of the polymer film was monitored. H+ generation at the vicinity of the electrode through the oxidation of ascorbic acid could be monitored by this technique. 相似文献
106.
Formation of carboxamides of a variety of carboxylic acids with the coupling reagent BBDI is described. This procedure permits a one pot and simple operation without the need of any bases and no base was required for even use of amine hydrochlorides. In addition, an approach to BBDI-catalyzed carboxamidation is examined. 相似文献
107.
108.
Koichi Ishibashi Hirohito Tsue Hiroki Takahashi Rui Tamura 《Tetrahedron: Asymmetry》2009,20(3):375-380
The first inherently chiral azacalix[4]arene has been prepared by introducing three benzyl groups onto the nitrogen bridges. The highly enantioenriched compound was easily obtained via a moderately enantioselective cyclization followed by a simple crystallization procedure. NMR and X-ray crystallographic studies revealed that easy access to the enantiomer was permitted by the non-racemizable 1,3-alternate conformation in solution, up to 110 °C, as well as by the preferential crystallization of a racemic compound. 相似文献
109.
Hideya Kawasaki Naoyuki Takahashi Hiroki Fujimori Kouji Okumura Takehiro Watanabe Chisato Matsumura Syusuke Takemine Takeshi Nakano Ryuichi Arakawa 《Rapid communications in mass spectrometry : RCM》2009,23(20):3323-3332
The pyrolytic highly oriented graphite polymer film (PGS) was first employed to analyze low‐mass analytes in environmental analysis by surface‐assisted laser desorption/ionization mass spectrometry (SALDI‐MS). PGS is a synthetic uniform and highly oriented graphite polymer film with high thermal anisotropic conductivity. We have found that negative ion mode SALDI‐MS using oxidized PGS (PGS‐SALDI‐MS) can be used to detect [M–H]? ions from perfluorooctanoic acid (PFOA) and other perfluoroalkylcarboxylic acids when the PGS surface is modified with the cationic polymer polyethyleneimine (PEI). The signal intensity of PFOA when employing the PEI modification showed a ten‐fold increase over that obtained from desorption/ionization on porous silicon (DIOS). PFOA was quantified using PGS‐SALDI‐MS and the calibration curve showed a wide linear dynamic range of response (20–1000 ppb). The combination of atmospheric pressure ionization and PGS (AP‐PGS‐SALDI) showed greater signal intensity than vacuum PGS‐SALDI for deprotonated PFOA. Several other environmentally important chemicals, including perfluoroalkylsulfonic acid, pentachlorophenol, bisphenol A, 4‐hydroxy‐2‐chlorobiphenyl, and benzo[a]pyrene, were also successfully used to evaluate PGS‐SALDI‐MS. In addition, we found that nonafluoro‐1‐butanesulfonic acid was able to produce protonated peptides in positive ion PGS‐SALDI‐MS, but that perfluoropentanoic acid and trifluoroacetic acid were not. It is suggested that perfluoroalkylsulfonic acids are better protonating agents than perfluoroalkylcarboxylic acids in SALDI‐MS. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
110.
Positivity - Let $$n\ge 2$$ be the spatial dimension. The purpose of this note is to obtain some weighted estimates for the fractional maximal operator $${{\mathfrak {M}}}_{\alpha }$$ of order... 相似文献