Hydrogen ion-selective electrode based on an iron-hydroxo-complex

Summary A new hydrogen ion-selective based on an iron hydroxo complex was proposed. The ion sensing membrane was composed of the iron(III) hydroxo complex, membrane solvent and polyvinyl chloride. The proposed electrode using 1-decanol as the most favourable solvent showed a linear pH-response from 0 to 5 with a potential change of 56 mV per pH-unit. The characteristics of the proposed electrode and a discussion on the response mechanism are reported.

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Wasserstoffionen-selektive Elektrode auf Basis eines Eisen-Hydroxo-Komplexes

Zusammenfassung Die Membran der vorgeschlagenen ionen-selektiven Elektrode besteht aus einem Eisen(III)-hydroxokomplex, dem Membran-Lösungsmittel und Polyvinylchlorid. Mit 1-Decanol als günstigstem Lösungsmittel ergab sich eine lineare Anzeige von pH 0 bis 5 mit einer Potentialänderung von 56 mV/pH. Die Charakteristik der vorgeschlagenen Elektrode wird beschrieben und der Ansprechmechanismus diskutiert.

     

Photodissociation of molecular beams of N2O4

A molecular beam of N₂O₄ molecules was photodissociated by an excimer laser at 193 and 248 nm. The time-of-flight distribution of NO₂ photofragments is consistent with the formation of two electronically excited NO_2* molecules in the ā(²B₂) or B?(²B₁) state. Visible emission from NO₂^* was observed in the photolysis at both 193 and 248 nm excitation. The parallel angular distribution of the NO₂ photofragments shows that at.193 nm N₂O₄ has a transition dipole along the N-N axis and the dissociative lifetime is estimated to be less than 1 ps.     

Application of long range j c-h resolved 2d spectroscopy (lrjr) in structural elucidation of natural products. The structure of oxirapentyn

The structure of a fungal metabolite, oxyrapentyn has been determined as shown in Fig. 7 by application of a new NMR technique, long range J C-H resolved 2D spectroscopy (LRJR).     

Effect of rotational relaxation on the intensity and polarization of fluorescence emission caused by sequential two-photo excitation

General formulas are derived for the intensity and the degree of polarization of the S_m-fluorescence emission (m ? 2) of a sample excited by the sequential two-photon excitation process (S_n ← S₁ ← S₀, n ? 2) with plane-polarized pulsed light. They show how the S_m-fluorescence intensity and anisotropy depend on the relative orientation of the relevant transition dipoles within a molecule and on the degree of rotational relaxation of molecules in the intermediate state (S₁) and in the S_m state (for the case m = n), or in the S_n → S_m process (m ≠ n).     

Total synthesis of (+)-pedamide. A new,remote controlled asymmetric induction

Total synthesis of optically active pedamide $\text{2}$, one of the tetrahydropyran moieties of the potent insect poison pederine $\text{1}$, was achieved by employing a new, remote controlled asymmetric reduction of a ketone as key step.     

On finite -submodules of Selmer groups of elliptic curves

In this note, we give another proof of a result of R. Greenberg on the non-existence of non-trivial finite -submodules of Selmer groups.

     

Development of a numerical wave tank for analysis of nonlinear and irregular wave field

A numerical wave-absorption filter has been developed for an open boundary condition in the analysis of nonlinear and irregular wave evolution. The filter is composed of a simulated sponge layer and Sommerfeld's radiation condition at the outer edge of the layer. The wave-absorption characteristics of the filter have been investigated by applying the linear potential theory and a two-dimensional nonlinear boundary element model. In both cases, the filter is found to he applicable for a wide range of wave parameters. In order to realize an idealized “numerical wave tank”, the present model also incorporates a nonreflective wave generator in the computational domain composed of a series of vertically aligned point sources. Numerous numerical experiments demonstrate that the present approach is effective in generating an arbitrary wave profile without reflection not only at the open boundaries but also at the wave generator.     

Stimulated Brillouin scattering and its dependences on strain and temperature in a high-delta optical fiber with F-doped depressed inner cladding

Stimulated Brillouin scattering (SBS) in a high-delta fiber with F-doped depressed inner cladding is studied through considering the interaction of acoustic and optical modes in the fiber. It is found that the number of acoustic modes in the fiber is reduced and the frequency spacing between neighboring modes is enlarged because of the F doping. The dependences of SBS on strain and temperature are measured and compared for each acoustic mode to investigate the feasibility of discriminative sensing of strain and temperature by use of the fiber.     

Synthesis and fluorescence of 2h‐pyrone derivatives for organic light‐emitting diodes (OLED)

2H‐Pyrone derivatives were synthesized through the reaction of aryl acetyl compounds with ketene dithioacetals in the presence of sodium hydroxide, and they showed very strong fluorescence in the solid state. The light‐emitting region of these 2H‐pyrones is 447‐630 nm in the solid states.