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981.
L. Trinkler B. Berzina M. Benabdesselam P. Iacconi L. Btter-Jensen K. Atobe 《Radiation measurements》2004,38(4-6):615-618
Spectral properties of cubic boron nitride have been studied using methods of photoluminescence (PL), X-ray excited luminescence (XL), thermoluminescence (TL) and optically stimulated luminescence. It is found that emission of cubic boron nitride is presented by 4 subbands, their relative yield is determined by the excitation type: blue, green (dominant) and red bands are observed in PL, ultraviolet, blue (dominant), green and red bands—in XL. Three thermal peaks are found in TL curves in the 0–700°C temperature range, their presence and intensity depend on radiation type used. A tentative correspondence between thermal peaks and emission bands is found. 相似文献
982.
983.
V. L. Solozhenko 《Journal of Thermal Analysis and Calorimetry》1995,44(1):97-103
The polymorphic transformations of wurtzitic modification of boron nitride into graphite-like ones have been studied using
DSC, inverse drop-calorimetry and dilatometry over the temperature range of 500 to 1400 K. The transformation enthalpies at
1380 K were determined to be +14±2 kJ/mole and +17±3 kJ/mole for wBN→hBN and wBN→rBN transformations, respectively.
Zusammenfassung Mittels DSC, inverser Dropkalorimetrie und Dilatometrie im Temperaturbereich von 500 bis 1400 K wurden die polymorphen Umwandlungen der Wurtzit-Modifikation von Bornitrid in die Graphit-Modifikation untersucht. Die Umwandlungsenthalpien bei 1380 K für die Umwandlungen wBN→hBN und wBN→rBN wurden mit +14±2 kJ/mol und mit +17±3 kJ/mol bestimmt.相似文献
984.
The effect of constraints on the initial steps of the incorporation of nitrogen on silicon has been assessed by calculations with the [Si9H12 + N] model cluster using density functional theory with the hybrid functional B3LYP, and two basis sets that differ significantly in size. The relative stability of the various stationary points is dependent on the type of constraints imposed on the cluster. Constrained calculations have predicted the structure with the nitrogen symmetrically bonded to the dimer silicons as the global minimum, however, if no constraint is imposed and the whole cluster is optimized, as done in this work, a structure with the nitrogen inserted between the dimer and the first layer and bonded to three silicon atoms is predicted to be the most stable one by about 17 kcal/mol by either the doublet or quartet route. The whole process is very exothermic and reaction barriers in the intermediate steps are easily overcome. Calculations with the smaller basis do not essentially change the major conclusion about the relative stability of the various stationary points. The most stable structure and frequency calculations are consistent with a planar NSi3 moiety and its asymmetrical stretching frequency. 相似文献
985.
N. A. Kovalenko T. L. Sen’ko T. S. Petkevich Yu. G. Egiazarov 《Journal of Applied Spectroscopy》2007,74(1):13-17
We have used IR spectroscopy of adsorbed CO to study the effect of the method for preparation of silver-palladium catalysts
on a TiO2 substrate and exposure to an oxidizing or reducing gaseous atmosphere on the state of Ag and Pd centers. We have shown that
as a result of the metal-support interaction, the reducibility of the Ag and Pd particles is increased, which leads to a change
in their adsorption and catalytic properties.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 16–20, January–February, 2007. 相似文献
986.
987.
988.
《中国化学》2018,36(3):194-198
Organic polymer solar cells (PSCs) have attracted increasing attention due to light weight, low cost, flexibility and roll‐to‐roll manufacturing. However, the limited light harvest range of the photoactive layer greatly restrains the power conversion efficiency (PCE) enhancement. In order to expand the light absorption range and further enhance the PCE of the PSCs, tandem structures have been designed and demonstrated. In tandem solar cell, the intermediate layer (IML) plays a critical role in physically and electrically connection of the two subcells. Herein, we apply titanium (diisopropoxide) bis(2,4‐pentanedionate) (TIPD) as both electrode modification layer and intermediate layer to investigate the feasibility in inverted tandem polymer solar cells. The same photoactive layers of PTB7‐Th:PC71BM are adopted in both front and rear subcells to simplify the evaluation of effectiveness of TIPD layer in tandem structures. By modulating the treatment condition of IML and the thickness of photoactive layer, efficient inverted tandem PSCs have been achieved with minimized voltage loss and excellent charge transportation, giving a best Voc of 1.54 V, which is almost two times that of the single bulk heterojunction (BHJ)‐PSC (0.78 V) and an enhanced PCE up to 8.11%. 相似文献
989.
Embedding Carbon Nitride into a Covalent Organic Framework with Enhanced Photocatalysis Performance 下载免费PDF全文
Junquan Pan Liping Guo Siquan Zhang Ning Wang Prof. Dr. Shangbin Jin Prof. Dr. Bien Tan 《化学:亚洲杂志》2018,13(13):1674-1677
We report a new strategy to construct porous carbon nitride (PCN) by embedding a heptazine unit–the primary building block of carbon nitride–into the backbone of a covalent organic framework (COF). The strategy results in a new type of PCN which bears a fibrous morphology, high surface area and wide visible absorption. The photocatalytic performance was evaluated by photodegradation of an organic dye. We found that the introduction of the heptazine unit has a prominent effect on the catalytic activity, which demonstrates an effective strategy to prepare carbon nitride materials. This work opens up a new way for the preparation of carbon nitride for photocatalysis applications. 相似文献
990.
Sh. G. Mkoyan Z. G. Aliev I. F. Urazovskii L. O. Atovmyan I. E. Nifant'ev K. A. Butakov 《Russian Chemical Bulletin》1996,45(9):2154-2156
The (C5H4-XMe2-C5H4) · (TiCl3)2 binuclear complexes, where X = Si (1) or C (2), have been studied by X-ray structural analysis. In both structures, the coordination polyhedra about the Ti atoms are distorted tetrahedra formed by three CI atoms and one Cp ring. The conformations of molecules1 and2 and the possibility of the occurrence of secondary Ti-Cp...Cl-Ti interaction are discussedTranslated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2269–2271, September. 1996. 相似文献