Effect of wall aperture on sound propagation within a tube

I.IntroductionInmanycasesthecontinuityofsoundpropagationwithinatubeisbrokenbyaperturesonthetubewallsuchastoneholesonthemainboreofwoodwindmusicalinstruments,rectangularsound-windowofChineseinstrumentshengetc.Thediscontinuityhaseffectonwavccncoun-tCringit.Keefestudicdasing1etoneholeofwoodwindinstrumentandrepresenteditbyaT-sectionequiva1entcirc.it[11.Inthispaper,theapertureontubewa1lisstudiedfromdifferentpointofview,a1thoughtheGreen'sfunctionmethodisalsousedinthetheoreticalana1ysis.Moresimp1er…     

Effects of Y(Ⅲ) Ions on the Fluorescence Properties of Ce(Ⅲ) Ion and the Organic Ligands in the Comp

ＥｆｆｅｃｔｓｏｆＹ（Ⅲ）ＩｏｎｓｏｎｔｈｅＦｌｕｏｒｅｓｃｅｎｃｅＰｒｏｐｅｒｔｉｅｓｏｆＣｅ（Ⅲ）ＩｏｎａｎｄｔｈｅＯｒｇａｎｉｃＬｉｇａｎｄｓｉｎｔｈｅＣｏｍｐｌｅｘＬＩＷｅｎ－ｌｉａｎ．（ＣｈａｎｇｃｈｕｎＩｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃｓ...     

聚亚甲基绿的性质

在 10～ 6 0℃范围内 ,测定了聚亚甲基绿的循环伏安图和交流阻抗图 ,测定了循环伏安所用电解质溶液的电导率随温度的变化 .在不同温度下 ,聚亚甲基绿的循环伏安图上均有一阳极峰和一阴极峰 ,阳极峰和阴极峰的峰电流均随温度升高而增加 ,即电极反应速率随温度升高而增加 .交流阻抗的结果表明 ,聚亚甲基绿的电荷传递电阻Rct随温度升高而增大 .热重 (TG)实验表明聚亚甲基绿热失重是分三步进行的 ,聚合物在 2 6 3 .1℃时发生分解 .扫描电镜 (SEM)结果显示聚亚甲基绿表面呈颗粒状     

Hydrodeoxygenation of benzofuran over sulfided and reduced Ni–Mo/γ-Al2O3 catalysts: Effect of H2S

Effect of H₂S on the catalytic performance of the reduced and sulfided Ni–Mo/Al₂O₃ catalysts in hydrodeoxygenation of benzofuran is studied. The steady-state reaction experiments showed a decrease in activity for both reduced and sulfided catalysts when H₂S was introduced into the feed. The reaction conversion of benzofuran over the reduced catalyst still remained superior to that of the sulfided catalyst in the presence of H₂S, however, at high reaction temperatures, the product distribution over the pre-reduced catalyst is similar to the sulfided catalyst. The studies with temperature-programmed desorption (TPD), temperature-programmed reaction (TPRxn) and X-ray photoelectron spectroscopy (XPS) techniques showed a partial sulfidation of the reduced catalysts when exposed to H₂S under reaction conditions, however, the catalyst does not go through a complete conversion to a molybdenum sulfide phase. Instead oxygen–sulfur exchange on the surface leaves behind oxisulfide species, with catalytic activity closely resembling that of the reduced catalysts. The effect of H₂S on the reaction performance is mainly coming from the competitive adsorption between H₂S and benzofuran and the formation of SH groups with decomposition of H₂S at high temperatures.     

Influence of a strong longitudinal static electric field on free carrier faraday effect in an n-type InSb at room temperature at submillimeter wave frequencies

The expression for free carrier Faraday rotation and for ellipticity , as the function of the applied parallel static electric field and static magnetic field for a given value of wave angular frequency and electron concentration N₀, are obtained and theoretically analyzed with the aid of one-dimensional linearized wave theory and Kane's non-parabolic isotropic dispersion law. It is shown that the maximum Faraday rotation occurs near the cyclotron resonance condition, which can be expressed as , where , , and . Here m^* and e denote the effective mass and charge of electron, respectively. _g is the forbidden bandgap of semiconductor. v₀ is the carrier drift velocity, which is a non-linear function of E₀ in high field condition. A possibility of a simple way of determining the non-linear v₀ vs E₀ characteristics of semiconductors by the measurement of Faraday rotation is also discussed.     

Solvent and pH Effects on the Electronic Spectra of Some Azo Benzimidazoles

The spectral behaviour of some new azobenzimidazoles in pure and mixed organic solvents and buffer solutions of varying pH have been studied. The observed bands are assigned to the possible electronic transition. The shoulder appearing in the visible region in the spectra of P‐NO₂ derivatives is ascribed to the existence of these compounds in azo‐hydrazone tautomeric equilibrium. The possibility of the formation of an intermolecular H‐bonded solvated complex between the molecules of p‐NO₂ derivatives and the proton acceptor solvents DMSO and DMF were studied. The pK values of these compounds were determined and explained on the basis of the relative contribution of acidic and basic character of respective species.     

降冰片二烯衍生物光敏异构化反应的机理研究

利用甲基卡唑为光敏剂，实现了三个降冰片二烯衍生物的光诱导介键异构化反应，荧光猝灭，化学诱导动态核极化（ＣＩＤＮＰ）以及热力学讨论都支持电子转移敏化机理，有关量子效率的计算表明单重态电子转移机制对光异构化反应的贡献远大于三重态能传递机制，此外还探讨了光异构化反应中的溶剂极性效应。     

动力极谱法测定海水中痕量锰

本文研究了孔雀绿极谐波性能,确定在醋酸-醋酸钠(pH=4.2)介质中,在示波极谱仪上可得到良好的极谱波。峰电位为-0.67伏(S.C.E)。用极谱法研究锰催化高碘酸钾氧化孔雀绿反应的机理。介绍了不需分离而直接测定海水中痕量锰的方法。其灵敏度可达0.2μg/l,对含10.1/μg锰的海水样进行11次平行测定,相对标准偏差为4.1%。本法亦适合自来水、河水中锰的分析。     

Synthesis and Mossbauer Spectra Studies of Mono-Binuclear Iron(III) Complexes with a Quinquedentate Ligand Derived from Saucylaldehyeds and Diethylenetriamine

Mono- and bi-nuclear iron(III) complexes of general formula [FeXL] and [LFe-Y-FeL](Bph₄)₂ have been prepared, and their spin state of iron atom in the complexes has been studied by means of the temperature dependence of the Mössbauer spectra, electronic spectra and magnetic measurement, where X is a mono- dentate ligand such as Cl-, NCS-, NCO-, N3-, pyridine and L denotes a quinquedentate Schiff base derived from salicylaldehyde and diethylenetriamine, and Y denotes bridged ligand such as pyrazine(pyr), 4,4′-bipyridine(bpy) and 4,4′-vinylenebipyridine(vibpy). On the basis of the Mössbauer and magnetic data, it was concluded that these complexes were all the high-spin (S = 5/2) slate. The effect of gamma ray irradiation for these complexes has been discussed.     

Cocrystallization of Two Different Pseudorotamers of Monocyclic Phosphorane Bearing Two Martin Ligands

Solution and crystal structures of monocyclic pentacoordinate phosphoranes bearing two Martin ligands and two carbon substituents are described. When the two carbon substituents are different, relative apicophilicity of the two monodentate carbon substituents could be determined based on the equilibrium ratio of the pseudorotamers. In some cases, x-ray structural analysis could be carried out and the crystallized structure from CH 3 CN is consistent with the major pseudorotamer in solution (CD 3 CN). Furthermore, when the equilibrium ratio of pseudorotamers is almost unity, novel cocrystallization of two pseudorotamers in a single crystal was observed.