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排序方式: 共有152条查询结果,搜索用时 250 毫秒
1.
MM. J. Duflos D. Letouz G. Queguiner P. Pastour 《Journal of heterocyclic chemistry》1973,10(6):1083-1084
This communication describes the synthesis of l-methyl-2,3-diformylpyrrole. This new compound is used to prepare a new heterocycle, l-methylcyclohepta[b]pyrrol-6-one and thus allows a new synthesis of l-methylpyrrolo[2,3-d]pyridazine. 相似文献
2.
G. Bigazzi J. C. Hadler Neto P. Iunes S. Meloni M. Oddone 《Journal of Radioanalytical and Nuclear Chemistry》1995,201(6):481-493
In the present paper the use of two natural uranium dosimeters is described. Data are compared with fluence values obtained by using NIST glass standards and the traditional activation of metal foils. Finally an example is reported for application of neutron dosimetry to the dating of the Fish Canyon Tuff age standard. 相似文献
3.
G. Bigazzi S. Meloni M. Oddone G. Radi 《Journal of Radioanalytical and Nuclear Chemistry》1986,98(2):353-363
Iron and trace elements, such as rare-earth elements, scandium, rubidium, cesium, tantalum, thorium and uranium were determined by instrumental neutron activation analysis in geological samples of obsidian rocks from the Mediterranean Area and in obsidian artifacts found in some prehistorical human settlements in Italy. REE patterns and discriminant analysis allow a firm identification of the source material of artifacts, thus confirming and implementing fission track data of the same artifacts and rocks on the origin of the obsidian rock used to mould the artifacts. 相似文献
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6.
V. C. Crespi N. Genova L. Tositti O. Tubertini G. Bettoli M. Oddone S. Meloni A. Berzero 《Journal of Radioanalytical and Nuclear Chemistry》1993,168(1):107-114
In the present investigation iron and trace elements were determined by instrumental neutron activation analysis in a number of sea bottom sediment samples, collected in the Ross Sea and close to the Italian Station at Terra Nova Bay in Antarctica. Full listing of results is presented and discussed as well as the evaluation of precision and accuracy. In order to find correlations and similarities among the sediment samples, the analytical data were submitted to statistical treatment. In addition rare earth element patterns were obtained. Typical trends were observed with no evident Eu negative anomaly and a depletion of heavy rare earth elements. 相似文献
7.
M. T. Ganzerli-Valentini S. Meloni V. Maxia U. Pisani 《Journal of Radioanalytical and Nuclear Chemistry》1973,16(1):191-204
The interactions between titanium dioxide, niobium pentoxide and tantalum pentoxide and 55 elements have been studied by batch
experiments in nitric acid. The variation of the distribution ccefficients with nitric acid concentration is presented and
discussed. The adsorption mechanism for some ions has also been investigated. Column experiments have been carried out to
check the practical use of the investigated oxides in radiochemical separations. A99mTc generator based on the use of TiO2 is also presented. 相似文献
8.
Dr. Robert Ludmerczki Prof. Luca Malfatti Dr. Luigi Stagi Dr. Manuela Meloni Prof. Carlo Maria Carbonaro Prof. Maria Francesca Casula Dr. Dóra Bogdán Dr. Stefania Mura Prof. István M. Mándity Prof. Plinio Innocenzi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(7):2543-2550
Carbonized polymer dots (CPDs), a peculiar type of carbon dots, show extremely high quantum yields, making them very attractive nanostructures for application in optics and biophotonics. The origin of the strong photoluminescence of CPDs resides in a complicated interplay of several radiative mechanisms. To understand the correlation between CPD processing and properties, the early stage formation of carbonized polymer dots has been studied. In the synthesis, citric acid monohydrate and 2-amino-2-(hydroxymethyl)propane-1,3-diol have been thermally degraded at 180 °C. The use of an oil bath instead of a more traditional hydrothermal reactor has allowed the CPD properties to be monitored at different reactions times. Transmission electron microscopy, time-resolved photoluminescence, nuclear magnetic resonance, infrared, and Raman spectroscopy have revealed the formation of polymeric species with amide and ester bonds. Quantum chemistry calculations have been employed to investigate the origin of CPD electronic transitions. At short reaction times, amorphous C-dots with 80 % quantum yield, have been obtained. 相似文献
9.
S. Bonella S. Meloni G. Ciccotti 《The European Physical Journal B - Condensed Matter and Complex Systems》2012,85(3):1-19
This paper reviews the transition path theory (TPT) for activated events and summarizes a set of methods and algorithms to compute all relevant quantities of this theory: free energy, rate and mechanism of the event. We provide a set of examples to illustrate the applicability of the methods to problems in chemistry, biophysics and material science. 相似文献
10.
D. Meloni R. Monaci M. G. Cutrufello E. Rombi I. Ferino 《Journal of Thermal Analysis and Calorimetry》2015,119(2):1023-1036