Implementing an efficient minimum capacity cut algorithm

In this paper, we present an efficient implementation of theO(mn + n ² logn) time algorithm originally proposed by Nagamochi and Ibaraki (1992) for computing the minimum capacity cut of an undirected network. To enhance computation, various ideas are added so that it can contract as many edges as possible in each iteration. To evaluate the performance of the resulting implementation, we conducted extensive computational experiments, and compared the results with that of Padberg and Rinaldi's algorithm (1990), which is currently known as one of the practically fastest programs for this problem. The results indicate that our program is considerably faster than Padberg and Rinaldi's program, and its running time is not significantly affected by the types of the networks being solved.Corresponding author.     

Electron density distribution in GaAs using MEM

Electron density distribution of GaAs is determined by means of the maximum entropy method (MEM) using reasonably good X-ray data collected at room temperature and 200 K. The bonding electron distributions are clearly visible in the MEM map and the mixed covalent-ionic character in GaAs is evidenced. The density distributions at 200 K show more condensed electronic clouds as compared to the room temperature map, preserving the trend in the bonding characters. The electron densities at the middle of the bond are 0.79 and 0.70 e/ų at 200 K and at room temperature, respectively. The refined harmonic thermal factors are in good agreement with the published values.     

In situ X-ray observation of phase transformation in Fe2O3 at high pressures and high temperatures

A laser-heated sample in a diamond anvil cell and synchrotron X-ray radiation was used to carry out structural characterization of the phase transformation of Fe₂O₃ at high pressures (30-96 GPa) and high temperature. The Rh₂O₃(II) (or orthorhombic perovskite) structure transforms to a new phase, which exhibits X-ray diffraction data that are indicative of a CaIrO₃-type structure. The CaIrO₃-type structure exhibited an orthorhombic symmetry (space group: Cmcm) that was stable at temperatures of 1200-2800 K and pressure of 96 GPa (the highest pressure used). Unambiguous assignment of such a structure requires experimental evidence for the presence of two Fe species. Based on the equation of state of gold, the phase boundary of the CaIrO₃-type phase transformation was P (GPa)=59+0.0022×(T−1200) (K).     

Excess attenuation of millimeter waves at window region due to atmospheric water vapor

The attenuation of 245.52 GHz millimeter wave was measured through a near ground horizontal path in order to study the anomalous water vapor absorption at the window region. The result demonstrates that the attenuation coefficient includes the quadratic dependence on the water vapor density. The quadratic component of the water vapor density in the expression of the attenuation was assumed to arises from the contribution of water dimers alone, then the concentration of water dimers was estimated adopting the published theoretical water dimers absorption coefficient. The obtained concentration was 0.062% of monomers in number when the water vapor density is 7.5 g/m³. This concentration is in agreement with the published result obtained by way of another method.     

Strain analysis for moiré interferometry using the two-dimensional continuous wavelet transform

In this paper, we introduce the two-dimensional continuous wavelet transform for the automated strain analysis of the moiré interference fringe pattern. The Fourier transform method has been widely used for automated analysis of an optical interference fringe pattern. However, this method is hardly applicable to the analysis of the fringe pattern, which includes large displacement range or discontinuities. We show the advantages of the wavelet transform method by applying it to experimental results on composite laminates.     

Upper limit of enhancement of boiling heat transfer in a narrow vertical rectangular channel due to passing bubbles

An experimental study has been made of saturated boiling heat transfer for water and R113 in a narrow vertical rectangular channel (2 mm space, 20 mm wide, and 200 mm long) at atmospheric pressure, in which the vertical heated surface (10 mm long and 20 mm wide) is located on one side at a position of 150 mm from its entrance and bubbles are forcibly passed through it at a designated period from 0.33 to 1.0 sec. The experiment shows that the heat transfer coefficients are increased by the bubble passing through the heated surface for the value of thermal diffusivity,a, times period, T₀, of the passing bubbles above about 6×10^–9 m² (a T ₀>6×10^–9 m²) while fora T ₀< 6×10^–9 m², the heat transfer coefficients become independent of the period and the effectiveness of the enhancement of the heat transfer owing to the passing bubble disappears.

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Die obere Grenze der Verbesserung des Wärmeübergangs beim Sieden in einem vertikalen, rechteckigen Kanal infolge von aufsteigenden Blasen

Zusammenfassung Es wurden Experimente über den Wärmeübergang beim Sättigungssieden mit Wasser und R113 in einem engen, vertikalen, rechteckigen Kanal (2 mm Abstand, 20 mm Breite und 200 mm Länge) bei Umgebungsdruck durchgeführt, wobei die vertikale, beheizte Oberfläche (10 mm lang und 20 mm breit) auf der einen Seite in einem Abstand von 150 mm vom Eintritt angeordnet ist und die Blasen zwangsweise durch den Kanal sich mit einem Periodenabstand von 0,033 bis 1,0 s bewegen. Das Experiment zeigt, daß die Wärmeübergangskoeffizienten durch das Vorbeistreichen der Blasen an der beheizten Oberfläche verbessert werden, wenn das Produkt aus Temperaturleitfähigkeit,a, mal der Periode, T₀, der vorbeistreichenden Blasen größer als 6×10^–9 m² liegt, während unterhalb dieses Wertes der Wärmeübergangskoeffizient unabhängig von der Blasenperiode ist und die Effektivität der Wärmeübergangsverbesserung infolge der Blasenströmung verschwindet.

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Nomenclature a thermal diffusivity of liquid - ¯h time-averaged heat transfer coefficient - q _w heat flux at wall - T ₀ period of passing bubble - T _w(t) temperature of heated surface - T _w amplitude of heated surface temperature Greek symbols thermal conductivity - thickness of liquid film     

On physical criteria for the selection of wood for soundboards of musical instruments

In order to develop criteria for the physical evaluation of wood for soundboards of musical instruments, measurements were made of dynamic Young's modulusE, static Young's modulusE, internal frictionQ ^–1 in longitudinal direction, and specific gravity for numerous species of broad-leaved wood. From the results obtained, including those of our previous paper on coniferous wood [1], it was found that the suitability of wood for soundboards could be evaluated by the quantity ofQ ^–1/(E/), and that there were very high correlations betweenQ ^–1/(E/) andE/, and betweenE andE, regardless of wood species. Consequently, it becomes possible to select practically any wood suitable for soundboards by using the value ofE/, which can be measured easily, and it was derived that the relation betweenE/ andQ ^–1 of wood could be expressed by an exponential equation regardless of wood species.     

Acid-induced conformational alteration of cis-preferential aromatic amides bearing N-methyl-N-(2-pyridyl) moiety

A series of cis-preferential aromatic N-methyl amides was designed and synthesized, and acid-induced conformational alteration of these compounds was investigated by means of NMR measurements in solution and X-ray crystal structure analysis. Compounds with a terminal N-methyl-N-(2-pyridyl) amide unit showed acid-induced conformational change from cis to trans, while those with a terminal N-methyl-2-pyridinecarboxamide unit showed a change of the carbonyl orientation from anti to syn with retention of cis conformation.     

Binding of metal ions by pyrimidine base pairs in DNA duplexes

Pyrimidine base pairs in DNA duplexes selectively capture metal ions to form metal ion-mediated base pairs, which can be evaluated by thermal denaturation, isothermal titration calorimetry, and nuclear magnetic resonance spectroscopy. In this critical review, we discuss the metal ion binding of pyrimidine bases (thymine, cytosine, 4-thiothymine, 2-thiothymine, 5-fluorouracil) in DNA duplexes. Thymine-thymine (T-T) and cytosine-cytosine (C-C) base pairs selectively capture Hg(II) and Ag(I) ions, respectively, and the metallo-base pairs, T-Hg(II)-T and C-Ag(I)-C, are formed in DNA duplexes. The metal ion binding properties of the pyrimidine-pyrimidine pairs can be changed by small chemical modifications. The binding selectivity of a metal ion to a 5-fluorouracil-5-fluorouracil pair in a DNA duplex can be switched by changing the pH of the solution. Two silver ions bind to each thiopyrimidine-thiopyrimidine pair in the duplexes, and the duplexes are largely stabilized. Oligonucleotides containing these bases are commercially available and can readily be applied in many scientific fields (86 references).