实施新课标新课程的新策略

为保证新课程教学目标的落实,需要把握好课程实施这个核心环节,课程实施的基本途径是教学活动。本文论述了为迎接新一轮高中课程改革、实施新课程需提前做好准备,教师需要通过校本教研,积累课程资源,研究教学策略,创造性地组织教学活动。     

Radiative Transitions of Singlet Oxygen: New Tools, New Techniques and New Interpretations

The near-IR phosphorescence of singlet delta oxygen, O₂(a¹Δg), has provided a wealth of information since it was first observed in solution-phase systems. The techniques employed and the quality of the data obtained have unproved significantly over the years that, in turn, presently makes it possible to address a wide variety of problems using both steady-state and time-resolved measurements. The development of spectroscopic methods to monitor other transitions in oxygen, specifically those that involve the singlet sigma state, O₂(b¹σ_g⁺), and the incorporation of high-level computational methods provides access to an even broader range of fundamental issues. The expertise presently available to monitor radiative transitions in oxygen, coupled with the current understanding of the effect of solvent on these transitions as achieved through state-of-the-art theoretical modeling makes it possible to consider the next step forward: the incorporation of spatial resolution and the construction of the singlet oxygen microscope.     

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Summary An efficient and economical GC method for rapid determination of FAMEs in rapeseed-mustard is described. The seeds were transmethylated with acetylchloride, using microwave heating and separation achieved on a 3 m column packed with a mixture of 2% SP-2300 and 3% SP-2310 on Chromosorb ‘W’. The method is compared with the conventional heating method and extended efficiently for half-seed analysis. The fatty acid composition of the FAMEs mixtures prepared by both methods was similar with highly significant correlation coefficients (P<0.001).     

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Summary Micromolar analyses of the nitrogen species NH₃, NO ₂ ^– , and NO ₃ ^– in soil and other samples are usually accomplished by extracting several samples and testing each for a different species. This procedure is not viable when the quantity of the initial sample is limited. An improved method of separating and analysing for ammonia NH₃(aq), nitrite NO ₂ ^– (aq), and nitrate NO ₃ ^– (aq) from a single small sample with concentrations of 0–50 mol/l is reported. No interferences or carryovers among the three nitrogen containing species were found. Uncertainties were ±2–5 mol/l and accuracies with respect to standards were ±3 mol/l.     

New methanetrisdiazeniumdiolates

Acetophenone and 1,3-biacetylbicyclo[1.1.1]pentane exhaustively condense all acidic α CH with nitric oxide in basic methanol to give methanetrisdiazeniumdiolates, RC(O)C(N₂O₂K)₃ either as a trianionic salt in the case of acetophenone or as a hexanionic salt in the case of 1,3-biacetylbicyclo[1.1.1]pentane.     

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Analytical and Bioanalytical Chemistry -     

New N-fluoroimines

Conclusions We have obtained the N-fluoroimidofluoride of difluoroaminodifluoric acid, the N-fluoroimine of difluoroaminopentafluoroacetone, and the N-fluoroimine of perfluoropyruvyl nitrile by reacting trifluoroethylene, 2-hydroperfluoropropylene, and 1,1,1-trifluoropropylene, respectively with tetrafluorohydrazine in the presence of KF.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1134–1135, May, 1968.     

New challenges

Accreditation and Quality Assurance -     

New books

Analytical and Bioanalytical Chemistry -     

New books

Critique and Bibliography

New books     

New aryl-tert-alkylnitroxyls

Russian Chemical Bulletin - The following stable nitrogen-containing free radicals were synthesized from aromatic nitro compounds and organomagnesium derivatives: p-diphenylaminophenyl-tert-butyl-,...     

New differential scanning calorimeter. New thermochemical applications

The described calorimeter is of fluxmetric, differential type. Thanks to the surrounding arrangement of the heat-flux-sensor, the sensitivity is independent of the sample characteristics: size, container type, kind of gas etc. Application to high-pressure experiments, is outlined. The general arrangement gives direct access to the sensitive zone from the outside: direct introduction of the sample; setting of electrical, mechanical, or pneumatic connections; application to the study of “open” chemical systems (gas-solid reactions). Examples of application are given.     

New books

Analytical and Bioanalytical Chemistry -     

New Editor-in-Chief

Accreditation and Quality Assurance -     

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Critique and Bibliography

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New book

Reviews and Bibliography

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