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71.
Vesselin Dimitrov Yanko Dimitriev Vili Mihailova 《Monatshefte für Chemie / Chemical Monthly》1983,114(6-7):669-674
The structure of glasses in the Fe2O3-V2O5 system in the 0–50 mol% Fe2O3 range is studied by IR-spectroscopy. It is found that the introduction of Fe2O3 favours the transformation of the VO5-groups into VO4 ones. This effect may be shown with the aid of IR-spectra, owing to the fact that these glasses are characterized by two high-frequency bands at 1020 and 930 cm–1. The first is determined by the vibrations of the short V=O nonbridging bonds in the VO5-groups, while the second is assigned to the vibrations of the V—O-bonds in deformed VO4-tetrahedra.
IR-spektroskopische Strukturuntersuchung von Gläsern des Systems Fe2O3-V2O5
Zusammenfassung Die Struktur von Gläsern des Systems Fe2O3-V2O5 in dem Bereich von 0–50 Molprozent Fe2O3 wurde mit Hilfe der IR-Spektroskopie untersucht. Zusatz von Fe2O3 begünstigt die Umwandlung der VO5- in VO4-Gruppen. Das kann in den IR-Spektren durch zwei Banden bei 1020 und 930 cm–1 festgestellt werden. Die erste wird durch Schwingungen der kurzen V=O-Nichtbrücken-bindungen in den VO5-Gruppen verursacht, die zweite wird auf Schwingungen der V—O-Bindungen in dem deformierten VO4-Tetraeder zurückgeführt.相似文献
72.
Matthias Otto Müller Stefan N. Groesser Silvia Ulli-Beer 《European Journal of Operational Research》2012,216(2):495-502
Collaborative research, defined as research involving actors participating in the problem situation under study, has an important role in operational research, strategic management and systems thinking. In a recent study, we found that a strong organizational focus incorporated into many soft operational research (OR) approaches is inadequate for studying societal problem situations, which are fragmented and have no clear boundary. Specifically, we failed to find a process of identifying individuals that is capable of representing the perspectives of actors and sufficient for research into societal problem situations. We found no clear terminology accounting for ontological differences between actors, individuals representing them and conceptual representations of acting entities. In response to this gap in the literature, we propose terminology that differentiates among actors (individuals or collective entities in the real world), experts (individuals capable of representing the perspective of an actor) and agents (ideal-typical representations of actors). Based on this terminology, we propose an iterative method to guide the assembly of an expert group to undertake collaborative research into societal problem situations. To demonstrate the application of our method, we present selected insights from our study in an electronic supplement. 相似文献
73.
通过对泰州长江公路大桥主缆送气量和送气压力的数据分析,给出了维护阶段悬索桥主缆漏气量和送气压力之间的半经验公式,对于后期悬索桥在设计使用过程中选择正确的送气压力和送气量有一定的借鉴意义。 相似文献
74.
Mahmood Tajbakhsh Majid M. Heravi Abolfazl Hosseini Ahmad Shahrezaiee 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):773-776
Hantzsch 1,4-dihydropyriines were rapidly and efficiently oxidized using bismuth nitrate supported onto silica gel under microwave irradiation. 相似文献
75.
76.
Abbas Shockravi Hashem Shargi Hassan Valizadeh Majid M. Heravi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2555-2559
An efficient synthesis of 3-substituted coumarins under solventless system is described. 相似文献
77.
Majid M. Heravi Hossein A. Oskooie Ladan Sangsefidi Mitra Ghassemzadeh Koroush Tabar-Hydar 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2843-2846
Oxidative deprotection of tetrahydropyranyl ethers (THP ethers) using chromium trioxide supported onto zeolite under microwave irradiation in solvent free condition is described. 相似文献
78.
The influences of steady aerodynamic loads on hunting stability of high-speed railway vehicles were investigated in this study.A mechanism is suggested to explain the change of hunting behavior due to actions of aerodynamic loads:the aerodynamic loads can change the position of vehicle system(consequently the contact relations),the wheel/rail normal contact forces,the gravitational restoring forces/moments and the creep forces/moments.A mathematical model for hunting stability incorporating such influences was developed.A computer program capable of incorporating the effects of aerodynamic loads based on the model was written,and the critical speeds were calculated using this program.The dependences of linear and nonlinear critical speeds on suspension parameters considering aerodynamic loads were analyzed by using the orthogonal test method,the results were also compared with the situations without aerodynamic loads.It is shown that the most dominant factors a ff ecting linear and nonlinear critical speeds are different whether the aerodynamic loads considered or not.The damping of yaw damper is the most dominant influencing factor for linear critical speeds,while the damping of lateral damper is most dominant for nonlinear ones.When the influences of aerodynamic loads are considered,the linear critical speeds decrease with the rise of cross wind velocity,whereas it is not the case for the nonlinear critical speeds.The variation trends of critical speeds with suspension parameters can be significantly changed by aerodynamic loads.Combined actions of aerodynamic loads and suspension parameters also a ff ect the critical speeds.The effects of such joint action are more obvious for nonlinear critical speeds. 相似文献
79.
80.
根据自己多年的工作经验,从系统的观念来阐述激烈市场竞争中PCB企业应对之道,管理心得。 相似文献