Experimental study on a separate type thermosyphon

The passages of vapor flow and the returning liquid flow, are perfectly partitioned in a separate thermosyphon. Therefore the flooding limit can be eliminated, and practicability based on its construction is highly evaluated. In the present work, a container tube made of heat resisting glass, in which an electric heater is inserted, is selected as the heating section of the experimental equipment. Distilled water is used as the working fluid. The influence of the heater type, the diameter of evaporating section and the liquid fill charge on the heat transfer performance have been studied. The larger heat transfer coefficient is achieved in the case of the U type heater, the larger tube diameter and the less liquid fill charge of the evaporating section. The useful correlation equations of the heat transfer coefficient in the evaporator have been derived.

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Experimentelle Untersuchung an einem Trennstrom-Thermosiphon

Zusammenfassung In einem Trennstrom-Thermosiphon sind die Strömungskanäle für die Dampfströmung und den Kondensatrücklauf vollkommen separiert. Die Flutgrenze kann deshalb unberücksichtigt bleiben. In dieser Untersuchung dient ein temperaturbeständiges Glasrohr mit innenliegender Heizung als Wärmequelle. Arbeitsmedium ist destilliertes Wasser. Untersucht wurden der Einfluß des Heizelementtyps, des Durchmessers der Verdampferstrecke und der Füllmenge auf das Wärmeüber-gangsverhalten. Das U-Typ Heizelement liefert bei größerem Rohrdurchmesser und geringerer Füllmenge in der Verdampferstrecke die höchsten Wärmeübergangskoeffizienten. Für diese wurden Korrelationsgleichungen aufgestellt.

     

Photoemission study on the valence band of a β-FeSi2 thin film using synchrotron radiation

Resonant and constant-initial state photoemission spectroscopies using synchrotron radiation were applied to investigate the valence-band electronic structure of a semi-conducting β-type iron-disilicide (β-FeSi(2)) thin film. The results clearly indicated that the component elements, iron (Fe) and silicon (Si), contribute differently to the valence band features; the Fe 3d orbitals mainly concentrate in the top region of the valence band while the Si 3s and 3p orbitals spread over the wide region of the valence band. The β-FeSi(2) thin film showed a typical p-type semi-conducting nature with a work function of 4.78 eV. The β-FeSi(2) film showed the Fe M(1)VV Auger lines around the kinetic energy of 88 eV. It would be expected from these observations that there exist strong interactions between iron and silicon atoms in the β-FeSi(2) film resulting in orbital mixing and band formation.     

Palladium-catalyzed denitrogenation reaction of 1,2,3-benzotriazin-4(3H)-ones incorporating isocyanides

1,2,3-Benzotriazin-4(3H)-ones and 1,2,3,4-benzothiatriazine 1,1(2H)-dioxide reacted with isocyanides in the presence of a palladium catalyst to give 3-(imino)isoindolin-1-ones and 3-(imino)thiaisoindoline 1,1-dioxides, respectively, in high yield. An intermediate azapalladacycle was generated through denitrogenation of the triazine moiety, and an isocyanide was incorporated therein.     

Variational Inequality Formulation of a Class of Multi-Leader-Follower Games

The multi-leader-follower game can be looked on as a generalization of the Nash equilibrium problem and the Stackelberg game, which contains several leaders and a number of followers. Recently, the multi-leader-follower game has been drawing more and more attention, for example, in electricity power markets. However, when we formulate a general multi-leader-follower game as a single-level game, it will give rise to a lot of problems, such as the lack of convexity and the failure of constraint qualifications. In this paper, to get rid of these difficulties, we focus on a class of multi-leader-follower games that satisfy some particular, but still reasonable assumptions, and show that these games can be formulated as ordinary Nash equilibrium problems, and then as variational inequalities. We establish some results on the existence and uniqueness of a leader-follower Nash equilibrium. We also present illustrative numerical examples from an electricity power market model.     

Heterogeneous critical nucleation on a completely wettable substrate

Heterogeneous nucleation of a new bulk phase on a flat substrate can be associated with the surface phase transition called wetting transition. When this bulk heterogeneous nucleation occurs on a completely wettable flat substrate with a zero contact angle, the classical nucleation theory predicts that the free-energy barrier of nucleation vanishes. In fact, there always exists a critical nucleus and a free-energy barrier as the first-order prewetting transition will occur even when the contact angle is zero. Furthermore, the critical nucleus changes its character from the critical nucleus of surface phase transition below bulk coexistence (undersaturation) to the critical nucleus of bulk heterogeneous nucleation above the coexistence (oversaturation) when it crosses the coexistence. Recently, Sear [J. Chem. Phys. 129, 164510 (2008)] has shown, by a direct numerical calculation of nucleation rate, that the nucleus does not notice this change when it crosses the coexistence. In our work, the morphology and the work of formation of critical nucleus on a completely wettable substrate are re-examined across the coexistence using the interface-displacement model. Indeed, the morphology and the work of formation changes continuously at the coexistence. Our results support the prediction of Sear and will rekindle the interest on heterogeneous nucleation on a completely wettable substrate.     

Mirror Map as Generating Function of Intersection Numbers: Toric Manifolds with Two Kähler Forms

In this paper, we extend our geometrical derivation of the expansion coefficients of mirror maps by localization computation to the case of toric manifolds with two Kähler forms. In particular, we consider Hirzebruch surfaces F ₀, F ₃ and Calabi-Yau hypersurface in weighted projective space P(1, 1, 2, 2, 2) as examples. We expect that our results can be easily generalized to arbitrary toric manifolds.     

Structures and fluorescence of secondary products produced from the cope-knoevenagel reaction of 2-phenylpropionaldehyde with methyl cyanoacetate

The Cope-Knoevenagel reaction of 2-phenylpropionaldehyde ( 7 ) with methyl cyanoacetate ( 8 ) produced methyl (E)-2-cyano-4-phenylpent-2-enoate ( 9 ) and the two highly fluorescent secondary products, 2-amino-3-carbomethoxy-6-phenyl-4-(1-phenylethyl)pyridine ( 10 ) and 3-cyano-6-phenyl-4-(1-phenylethyl)-2-pyridone ( 11 ). The structure of 10 was determined by X-ray crystallography while the structure of 11 was confirmed by the conversion of 9 into 11 . The mechanism of their formation is discussed. Fluorescence of 10 and 11 and the related compounds are also described.     

Direct mono-phosphorylation of 1,3-diols. A synthesis of FTY720-phosphate

A novel method for selective and direct phosphorylation of various 1,3-diols using silver(I) oxide, tetrabenzyl pyrophosphate (TBPP), and tetrahexylammonium iodide affording mono-phosphates was developed. We applied the present method to the synthesis of FTY720-phosphate.