奥尔堡PBL模式对提升有机波谱分析教学效果的启示

概述了有机波谱分析课程教学中存在的主要问题，介绍了奥尔堡PBL模式的主要特点和优势，分析了将奥尔堡PBL模式用于有机波谱分析课程教学的必要性和可行性，并从课时分配、教学内容、教学方式和考核方式等4方面提出了教学改革方案，旨在提高教学效果。     

Effects of Adsorbed Polyaniline on Redox Process on MoO3 Surface

The effects exhibited by adsorbed conducting polyaniline on the redox process on a molybdenum oxide surface were studied. Thermogravimetric results indicate a 4% polyaniline deposition. Cyclic voltammograms of the adsorbed polymer on MoO3 show that polyaniline exerts remarkable effects on the molybdenum blue oxidation-reduction process, with oxidation and reduction potentials of 0.33 and 0.18 V, respectively. This effect strongly enhances the electrode response, and can be used as an important tool in qualitative and/or quantitative determinations of molybdenum in solution as well as in any substrate. Copyright 1999 Academic Press.     

Observation of microwave-induced zero-conductance state in Corbino rings of a two-dimensional electron system

Using Corbino samples we have observed oscillatory dc conductance in a high-mobility two-dimensional electron system when it is subjected to crossed microwave and magnetic fields. At the strongest of the oscillation minima the conductance is found to be vanishingly small, indicating a macroscopic insulating state associated with this minimum. With increasing voltage bias, a crossover from Ohmic to electron-heating regime is observed.     

Relaxation of polarized nuclei in superconducting rhodium

Nuclear spin lattice relaxation rates were measured in normal and superconducting (sc) rhodium with nuclear polarizations up to p = 0. 55. This was sufficient to influence the sc state of Rh, whose T(c) and B(c) are exceptionally low. Because B(c)相似文献   

Synthesis of heterocyclic thiosulfonates

[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity.     

Studies on coordination compounds vii,chromatographic, thermoanalytical and spectroscopic studies on thermal decomposition of cadmium(II) and lead(II) salicyl-aldoximates

On the basis of decomposition temperatures and infrared spectra, cadmium(II) and lead(II) bissalicylaldoximates were considered to havetrans andcis structures, respectively.In the first stage bis(salicylaldoximato)cadmium(II) decomposes thermally like bis(salicylaldoximato)lead(II), with one ligand molecule leaving, but the intermediate is unstable and immediately decomposes further. The oxidation of the end- product is a rapid, exothermic reaction, probably catalyzed by cadmium metal. The mass spectrum of (C₇H₆O₂N)₂ Cd points to a different decomposition scheme than that elucidated through the pyrolysis decomposition products. This may be due to a catalytic effect of the ionization chamber. The thermal properties of (C₇H₅O₂N) Cd support the preceding views.TG curves showed the decompositions of mono(salicyl-aldoximato) lead(II) and the intermediate of bis(salicyl-aldoximato) lead(II) to be similar. The mass spectra of the chelates confirmed the formation of the same polymer (m/e 222) in both decompositions. Only the mass spectrum of (C₇H₅O₂N)Pb exhibited the molecular peakm/e 343. The decomposition schemes of the lead(II) salicylaldoximates were therefore elucidated more exactly. The metallic lead seems not to catalyze the oxidation of the organic part.

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Zusammenfassung Aufgrund der Zersetzungstemperatur und der Infrarotspektrum werden Cadmium(II)- und Blei(II)-bisalicylaldoximate als Verbindungen mit trans- bzw. cis-Struktur angesehen. Im ersten Schritt wird Bis-(salicylaldoximato)-blei(II) unter Abspaltung eines Ligandmoleküls zersetzt, die Zwischenverbindung ist jedoch nicht stabil und zersetzt sich sofort weiter. Die Oxydation des Endproduktes ist eine schnelle exotherme, wahrscheinlich durch metallisches Cadmium katalysierte Reaktion. Das Massenspektrum von (C₇H₆O₂N)₂ Cd weist auf ein Zersetzungsschema hin, das sich von dem aus den pyrolytischen Zersetzungsprodukten abgeleiteten unterscheidet. Dies ist möglicherweise auf einen katalytischen Effekt der Ionisationskammer zurückzuführen. Die thermischen Eigenschaften von (C₇H₅O₂N)Cd unterstützen diese Auffassungen. Aus den TG-Kurven ist zu ersehen, dass die Zersetzungen von Mono(salicylaldoximato)-blei(II) und des Zwischenproduktes von Bis(salicylaldoximato)-blei(II) ähnlich sind. Massenspektren der Chelate bestätigen die Bildung des gleichen Polymers (m/e 222) bei der Zersetzung beider Verbindungen. Nur im Massenspektrum von (C₇H₅O₂N)Pb tritt der Molekularpeak (m/e343) auf. Die Zersetzungsschemata der Salicylaldoximate von Blei(II) sind deshalb genauer aufgeklärt. Metallisches Blei scheint die Oxydation der organischen Komponente nicht zu katalysieren.

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A Continuous-Wave Ho：YA103 Laser with Output 8.5 W Pumped by a 1.91μm Laser at Room Temperature

A cw high efficient Ho：YAI03 laser pumped by 1.91 μm diode-pumped Tm：YLF laser at room temperature is realized. The maximum output power reaches 8.5 W when the incident pump power is 15.6 W. The slope efficiency is 63.7%, and the Tm：YLF to Ho：YAP optical conversion efficiency is 54.5%. The laser wavelength is 2118.3nm when the transmission of output coupler is 30%. The beam quality factor is M2 -1.39 measured by the traveling knife-edge method.     

Crystal and molecular structures of hexaaquazinc(II)isonicotinate n-oxide and catena-diaquabis-μ-(isonicotinato n-oxide)cadmium(II)

[Zn(H₂O)₆](N-inicO)₂ is an ionic compound made up of hexaaqua metal cations and isonicotinate N-oxide anions. It forms an isomorphic series with the corresponding Mg²⁺, Fe²⁺, Co²⁺ and Ni²⁺ compounds.In [Cd(N-inicO)₂(H₂O)₂]_n complex, coordination takes place through the NO oxygen and one of the (COO) oxygens with ligand forming thus a double bridge between Cd²⁺ ions. The structure is an endless chain stretching diagonally through the unit cell.The coordination polyhedron in both compounds is almost undistorted octahedron.     

Scanning Michelson interferometer for imaging surface acoustic wave fields

A scanning homodyne Michelson interferometer is constructed for two-dimensional imaging of high-frequency surface acoustic wave (SAW) fields in SAW devices. The interferometer possesses a sensitivity of ~10(-5)nm/ radicalHz , and it is capable of directly measuring SAW's with frequencies ranging from 0.5 MHz up to 1 GHz. The fast scheme used for locating the optimum operation point of the interferometer facilitates high measuring speeds, up to 50,000 points/h. The measured field image has a lateral resolution of better than 1 mu;m . The fully optical noninvasive scanning system can be applied to SAW device development and research, providing information on acoustic wave distribution that cannot be obtained by merely electrical measurements.