Effect of dimension on charge order domain in Ruddlesden-Popper manganites

The charge order (CO) domains of dimensionally controlled manganites Pr_1−xCa_xMnO₃ and Pr_1−xCa_1+xMnO₄ (x=0.5, 0.6 and 0.67), which have three-dimensional (3D) and two-dimensional (2D) Mn-O networks, respectively, have been studied by transmission electron microscopy (TEM). Although the electron diffraction data show similar dependences of the modulation wave vector on hole doping x, there are distinctive differences between the 3D and 2D systems in terms of the CO domain sizes. In the 2D system, the TEM images show that the domain size is almost constant irrespective of hole doping x. On the other hand, in the 3D system, the domain size of the incommensurate CO for x=0.6 is much smaller than those of the commensurate CO for x=0.5 and 0.67. Namely, in the 3D system, the CO states are strongly influenced by the incommensurability for the parent lattice. This difference indicates that the dimension of the Mn-O network plays a crucial role in the CO domain and suggests that the electron-lattice coupling of the 3D system is stronger than that of the 2D system.     

Invariant theory for singular α-determinants

From the irreducible decompositions' point of view, the structure of the cyclic GLn(C)-module generated by the α-determinant degenerates when (1?k?n−1) (see [S. Matsumoto, M. Wakayama, Alpha-determinant cyclic modules of gln(C), J. Lie Theory 16 (2006) 393-405]). In this paper, we show that -determinant shares similar properties which the ordinary determinant possesses. From this fact, one can define a new (relative) invariant called a wreath determinant. Using (GLm,GLn)-duality in the sense of Howe, we obtain an expression of a wreath determinant by a certain linear combination of the corresponding ordinary minor determinants labeled by suitable rectangular shape tableaux. Also we study a wreath determinant analogue of the Vandermonde determinant, and then, investigate symmetric functions such as Schur functions in the framework of wreath determinants. Moreover, we examine coefficients which we call (n,k)-sign appeared at the linear expression of the wreath determinant in relation with a zonal spherical function of a Young subgroup of the symmetric group Snk.     

Image-based sizing of surface-breaking cracks by SH-wave array ultrasonic testing

This paper presents calibration-free crack sizing techniques based on ultrasonic imaging. The techniques are intended for 2D (line) surface-breaking cracks with the size of the incident wavelength or greater. The probing wave mode is the anti-plane shear wave (SH-wave). Two methods are employed for the ultrasonic imaging. One is a synthetic aperture focusing technique (SAFT) and the other is a computed time-reversal focusing technique (TRFT). In this paper, those methods are modified so that crack tips are located directly from measured A-scope waveforms without any calibration experiments. The results are shown as a peak in the ultrasonic image created by the respective methods. Reasonable accuracies of the proposed techniques are demonstrated first for the sizing of slits with known depths. The techniques are applied thereafter to the sizing of fatigue cracks. Since fatigue cracks may not be open without an external load, ultrasonic measurements are taken with and without external loads. The results of the imaging show that the depths of open cracks can be estimated accurately. It is also shown that crack opening (closing) behavior can be deduced by observing appearance (disappearance) of the peak in the images indicating the crack tip.     

Analysis of protein-protein interactions with a multi-capillary electrophoresis instrument

Protein-protein interactions were analyzed by zone electrophoresis of premixed equilibrium mixtures of a fluorescence-labeled protein at a constant concentration and unlabeled protein at a variety of concentrations using a 96-CE instrument equipped with a LIF detector. The interactions between labeled-con A versus succinylated ovalbumin, labeled-trypsin versus four proteinaceous trypsin inhibitors and labeled-insulin versus seven anti-insulin monoclonal antibodies were analyzed using a dual buffer system, in which a 60 mM borate-Na buffer (pH 9.35) was used as electrophoresis buffer and 60 mM MOPS-Na (pH 7.35) containing 0.1% Tween 20 was used as a sample buffer. The dual buffer system allowed fast and reproducible analyses of interactions at a physiological pH using uncoated fused-silica capillaries. The change in the mobility moment, the first statistical moment of an electropherogram on the mobility axis (Shimura, K., Uchiyama, N., Enomoto, M., Matsumoto, H., Kasai, K., Anal. Chem. 2005, 77, 564-572), of the labeled proteins were analyzed as a function of the concentration of unlabeled proteins. The dissociation constants for seven antibodies ranging from sub nanomolar to micromolar was determined based on the results of one cycle of parallel electrophoresis runs, which completed in 30 min using 20 pmol (120 ng) of labeled insulin and 5 pmol (750 ng) each of the mAb.     

Evaluation of probe size in STEM imaging at 30 and 60 kV

In order to estimate the probe size on the specimen surface in a newly developed low-acceleration-voltage (30–60 kV) atomic-resolution scanning transmission electron microscopy (STEM), we compared the intensity profiles of experimentally obtained annular dark field (ADF)-STEM images of Si–Si dumbbells and those of images simulated using a multislice method which takes chromatic aberration into account. However, the simulated ADF images at 30 and 60 kV were found not to match the corresponding experimental images. Subsequently, the simulated images were convolved with probe functions (normal distributions) of different widths until a good match was obtained between the images. This allowed the probe shapes corresponding to the experimental conditions to be determined. ADF-STEM images with chromatic aberration could then be calculated by an incoherent superposition of these probe functions over a range of energies. The full widths at half maximum for the probe functions were estimated to be 99.2 pm for 30 kV and 92.8 pm for 60 kV. The D59 diameters were calculated to be 154.0 pm for 30 kV and 127.8 pm for 60 kV. This means that the 30-kV probe has a larger tail than the 60-kV probe.     

Novel Hole‐Transport Material for Efficient Polymer Light‐Emitting Diodes by Photoreaction

Summary: The photo‐crosslinking of carbazole dendrimers was analyzed by UV and IR spectroscopic methods. Photoirradiation results in the formation of a film that is insoluble in toluene and benzene. Time‐of‐flight mass spectrometry studies revealed that the photoirradiation lead to an oligomerization of the dendrimer through crosslinking. The resulting insoluble dendrimer film could be applied as a hole‐transport layer in efficient polymer electroluminescence devices (PLEDs).

Luminance‐voltage characteristics for PLEDs wherein PEDOT:PSS and CbzG3 complex with SnCl₂ were employed as the hole transport layer (ITO/HTL/EML/Ca/Ag).     

Crystal Structure of Diethyl 2‐[2,2,2‐ trifluoro‐1‐(indole‐3‐yl)‐ethyl]‐2‐acetamidomalonate

The title compound (C₁₉H₂₁F₃N₂O₅) has been determined from three dimensional X‐ray diffraction data. The crystals are monoclinic, a = 7.626(4)Å, b = 17.515(4)Å, c = 15.066(3)Å, β = 101.02(3)°, V = 1975(1)ų, Z = 4, D_calc = 1.393g cm^‐3, space group P2₁/c. The structure was solved by direct methods and refined by full‐matrix least‐squares method (R = 0.039).