摘要:

AbstractThe problem of the rapid anodical photoelectrochemical desintegration of visible‐light‐sensitive semiconductor electrodes (e.g. CdS, GaAs) in presently investigated continuously operating electrochemical solar cells is tackled by two improvements:a) The use of covalent layer‐type transition metal dichalcogenides as electrode material, in which photon absorption involves d‐d transitions and does not produce a splitting of chemical bonds andb) the operation of the transition metal dichalcogenides as photo‐cathodes, which is possible with p‐conducting material.The first photocell of this kind is constructed with p‐conducting natural MoS2layer crystals and Fe2+/3+as redox‐couple. It proved to be stable during longtime experiments. A power output of up to 1% was obtained. The limiting factor was found to be the insufficient solid state behaviour of the available natural crystals (high recombination losses through traps, weak p‐character). A considerable improvement is to be expected from better quality p‐type electrode‐material.Some development possibilities for solar cells, based on covalent semiconducting layer‐type transition metal dicha

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810403

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractSpectra acquisition of short‐lived intermediates is enabled by electrogeneration at optically transparent electrodes using a rapid scanning spectrometer and a computer controlled signal averaging technique. Spectra can be taken at a maximum speed of 5 μsec per point and a sensitivity of 10−4absorbance unit at a signal‐to‐noise ratio of one after about 900 averages. The capability of the technique is illustrated by spectra acquisition of radical cations generated by anodic oxidation of 4, 4'‐dimethoxystilbene, 3, 4‐dimethoxy‐propenylbenzene, 1, 1'‐dianisylethylene, and p‐metho

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810404

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractZunächst wird die Thermokraft von geschmolzenem Silbernitrat im Temperaturbereich von 220 °C bis 360 °C untersucht Die experimentellen Werte lassen sich analytisch mit einer mittleren Abweichung von ±0, 7 μV K−1darstellen und befinden sich in guter Übereinstimmung mit Literaturdaten. Die Überführungsentropien der Silberionen in reinem Silbernitrat werden berechnet.Mit der gleichen Thermokette werden die Anfangswerte der Thermokraft der binären Schmelzen LiNO3+ AgNO3und NaNO3+ AgNO3im Temperaturbereich von 220 °C bis 300 °C und im gesamten Konzentrationsbereich untersucht, soweit dies das Phasendiagramm der Schm

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810405

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractDissolution rates of the solid solutions MgO—FeO and MgO—CoO and the ternary compounds MgFe2O4, ZnFe2O4, NiFe2O4, FeCr2O4and NiCr2O4in acidic solutions have been investigated in the same way as for the dissolution of binary metal oxides previously reported [2]. In some cases preferential dissolution of one or the other oxide component has been obser

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810406

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractThe anodic evolution of Iodine from solid α‐AgI was studied in the solid‐state cell Ag/AgI/I2(g), Graphite at different I2‐pressures and temperatures. A single pulse galvanostatic technique was used. The kinetic parameters obtained allowed the postulation of a fast discharge‐slow recombination (at low coverage) reaction mechanism. A dependence of the exchange current density upon the iodine partial pressure was found and interpreted on the basis of the postulated mechanism. A sort of “anode effect

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810407

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractSeveral basic types of phase diagrams for binary and ternary water‐salt systems may be elucidated from experimental investigations of phase equilibria to elevated temperatures (up to 550 °C) and pressures (up to 2.5 kbar). The temperature dependence of some physico‐chemical quantities as the concentrations of solutions in monovariant equilibria, molar volumes, electrical conductivities and spectroscopic properties are carefully analysed. The results indicate a clearly different behaviour between dilute and concentrated hydrothermal solutions. The salt concentrations where the transition between water like and melt like characteristics in 1:1, 1:2, 2:2 electrolyte solutions occurs are determined and the correlation of these concentrations with the molecular characteristics of electrolytes are establi

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810408

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractIn relaxation experiments on aqueous solutions of surfactants one observes two processes. Following the pioneer work of Aniansson and Wall, the fast process is attributed to the change of the mean aggregation number of the micelles, while the slower one is attributed to the change of the total number of micelles. In this paper, the analysis of the fast relaxation process is first clarified. Second, the slower of the two relaxation processes is reexamined. It is suggested that their assumption of negligible flux in the abundant region leads to unphysical behavior of the micelle distribution. An alternative treatment is given which leads to a different result. The concentration dependence of the time constant is then derived for ionic systems in which the role of the counter ions has to be considered. This new result for the slow relaxation process together with the original result for the fast relaxation process are compared with experiments on the ionic systems H2O — NaTS and H2O — TTABr. Since results for nonionic systems form a limiting case of the more general results, comparison with experiments on the nonionic Triton‐X‐100 is also made. Satisfactory agreements are obtained for both types of

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810409

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractDie Intensität der indirekten Chemilumineszenz gemeinsamer Lösungen von Tetramethyl‐1, 2‐dioxetan(TMD) und 9, 10‐Dibromanthrazen (DBA) in Toluol wurde in Abhängigkeit von Akzeptorkonzentration und hydrostatischem Druck bei 40 °C untersucht. Die Ergebnisse werden in Verbindung mit der ebenfalls ermittelten Druckabhängigkeit der Fluoreszenz von DBA und der bereits früher bestimmten Druckabhängigkeit der Zerfallskonstanten des TMD diskutiert. Es kann gezeigt werden, daß die Energieübertragung von Aceton im Triplettzustand3A1auf DBA in Lösung eine spinerlaubte TT‐Energieubertragung ist. Dabei wird die Energie in einem diffusionskontrolliert verlaufenden Stoßprozeß von3A1auf DBA transferiert, wobei der zweite angeregte Triplettzustand3DBA2angeregt wird. Durch nachfolgendes intersystem crossing kann der fluoreszenzfähige angeregte Singulettzustand1DBA1erreicht werden. Die konkurrierende Energieübertragung auf den niedrigsten angeregten Triplettzustand3DBA1erfolgt ebenfalls diffusionskontrolliert. Dieser Zustand wird jedoch strahlungslos desaktiviert. Die Ausbeute des intersystem crossing von3DBA2nach3DBA1wi

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810410

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractThe reorientational motions of (CH3)3NHCl in liquid HCl are studied. The (CH3)3NHCl molecules are coupled to the solvant by hydrogen bonding, forming complexes of the form:The analysis of the Raman bands of the C‐N vibration of A1and E symmetry gives the rotational diffusion constants:DL= (0.07 ± 0.015) 1012s−1for the reorientation of the cation perpendicular to the molecular symmetry axis, andD||= (0.16 ± 0.10) 1012s−1for the reorientation of the cation about its molecular symmetry axis. The values for the diffusion constants indicate a collision induced relaxation mechanism for both reorientations of the

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810411

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractA critical evaluation of diffusion data and measurements of the nonstoichiometry as a function of the oxygen potential in magnetite allows the following conclusions to be drawn: At high oxygen potential, magnetite exists with a cation deficit (cation vacancies); at low oxygen potential, magnetite exists with a cation excess (interstitial cations). Assuming the point defects to form an ideal solution with the crystal, the point defect thermodynamics describes the known data on diffusion and nonstoichiometry in magnetite quantitatively. The mobility of interstitial iron cations in magnetite (atT= 1200°C) is approximately 15 times faster than the cation vacancy mobility

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810412

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY