Experimental optimization of p-polarized MAIR spectrometry performed on a fourier transform infrared spectrometer.

Optimized experimental conditions of infrared p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS) for the analysis of ultrathin films on glass have been explored. When the original MAIRS technique is employed for thin-film analysis on a substrate of germanium or silicon, which exhibits a high refractive index, an established experimental condition without optimization can be adapted for the measurements. On the other hand, the p-MAIRS technique that has been developed for analysis on a low-refractive-index material requires, however, optimization of the experimental parameters for a 'quantitative' molecular orientation analysis. The optimization cannot be performed by considering only for optics in the spectrometer, but for optics concerning the substrate should also be considered. In the present study, an optimized condition for infrared p-MAIRS analysis on glass has been revealed, which can be used for quantitative molecular orientation analysis in ultrathin films on glass.     

A new laser ablation system for quantitative analysis of solid samples with ICP-MS.

The laser ablation (LA) method is an effective technique for quantitative analysis. In the present work, a new LA system was developed for the high-sensitivity analysis of metal materials using inductively coupled plasma mass spectrometry (ICP-MS). This system consists of a high-frequency Q-switched laser and 2 scanning mirrors for scanning the ablation spot in an adequately large area of the specimen without vacant spaces. The influence of elemental fractionation (non-stoichiometric generation of vapor species) can be eliminated by repetitive irradiation of this pattern on the same area. Particles generated with an average laser power of 0.6 W with the developed LA system gave intensity and stability substantially similar to that of a 500 microg/ml solution steel sample in solution ICP-MS. The analytical performance of the developed LA-ICP-MS was compared with that of a solution ICP-MS using NIST steel SRMs. The performance of the newly-developed system is comparable to that of conventional solution ICP-MS in both accuracy and precision. The correlation coefficients between the contents and the intensity ratios to Fe were over 0.99 for most elements. The relative standard deviation (RSD) obtained by LA-ICP-MS revealed that this system can analyze iron samples with good precision. The results of ultra trace level analysis of high-purity iron showed that developed LA-ICP-MS is capable of analyzing ppm concentration levels with a 20 - 30 ppb level standard deviation. The detection limit was on the order of 10 ppb for most elements.     

Future directions for higher-efficiency HIT solar cells using a Thin Silicon Wafer

To reduce the power generation cost of heterojunction with intrinsic thin layer (HIT) solar cells, it is necessary to use a thinner crystalline silicon wafer, as well as to improve the conversion efficiency. We have experimentally confirmed that V_OC of the HIT solar cell increases with decreasing the wafer thickness, and can reach a very high V_OC of 747 mV with a 58-μm-thick wafer owing to a sufficiently low surface recombination velocity. We also indicate the future directions for improving the efficiency. The uniformization of the texture size of the silicon surface and reduction of the carrier density in TCO film while maintaining an equal or lower conductivity are effective for improving the optical confinement.     

In vitro Evaluation of Osteoblast Response to Sol-Gel Derived Gelatin-Siloxane Hybrids

Cytotoxicity and cytocompatibility of porous gelatin-siloxane hybrids were evaluated due to osteoblastic cell (MC3T3-E1) proliferation, ALP activity, or their responses to the hybrids and their extracts. The hybrids were found intoxic, and appropriate incorporation of calcium ions stimulated proliferation and differentiation in vitro. Cells were seeded into the porous hybrids and the cell morphology was studied. The hybrids involving calcium ions favored osteoblast growth and differentiation.     

Setting angle of molecular chains in polyethylene crystals

The setting angles of chains in solution-grown crystals of paraffins were measured from optical transforms of their electron diffraction patterns. Those of solution-grown, melt-crystallized, and drawn polyethylenes were determined by the x-ray diffraction method. The cell dimensions, paracrystalline disorder, and thickness and size of crystallites of these specimens were measured. From these data, factors increasing the setting angle were found as follows; (1) folding of molecular chains, (2) imperfections of crystal lattice, (3) expansion of cell dimensions and (4) smallness of thickness and lateral size of crystallites. The temperature dependence of the setting angle is also discussed; the higher the temperature, the larger the setting angle. At low temperatures, the setting angle also increases, and the values are compared with those predicted theoretically from the minimization of lattice energy. The temperature dependence of the setting angle is interpreted in terms of a conformational change of the stem segments in the crystalline core.     

A Ferroelectric Metallomesogen Exhibiting Field-Induced Slow Magnetic Relaxation

Magnetoelectric (ME) materials exhibiting coupled electric and magnetic properties are of significant interest because of their potential use in memory storage devices, new sensors, or low-consumption devices. Herein, we report a new category of ME material that shows liquid crystal (LC), ferroelectric (FE), and field-induced single molecule magnet (SMM) behaviors. Co(II) complex incorporating alkyl chains of type [Co(3C₁₆-bzimpy)₂](BF₄)₂ ( 1 ; 3C₁₆-bzimpy=2,2’-(4-hexadecyloxy-2,6-diyl)bis(1-hexadecyl-1H-benzo[d]imidazole)) displayed a chiral smectic C mesophase in the temperature range 321 K–458 K, in which distinct FE behavior was observed, with a remnant polarization (88.3 nC cm⁻²). Complex 1 also exhibited field-induced slow magnetic relaxation behavior that reflects the large magnetic anisotropy of the Co(II) center. Furthermore, the dielectric property of 1 was able to be tuned by an external magnetic field occurring from both spin-lattice coupling and molecular orientational variation. Clearly, this multifunctional compound, combining LC, FE, and SMM properties, represents an entry to the development of a range of next-generation ME materials.     

New algorithms for convex cost tension problem with application to computer vision

Motivated by various applications to computer vision, we consider the convex cost tension problem, which is the dual of the convex cost flow problem. In this paper, we first propose a primal algorithm for computing an optimal solution of the problem. Our primal algorithm iteratively updates primal variables by solving associated minimum cut problems. We show that the time complexity of the primal algorithm is $O(K?T(n,m))$, where $K$ is the range of primal variables and $T(n,m)$ is the time needed to compute a minimum cut in a graph with $n$ nodes and $m$ edges. We then develop an improved version of the primal algorithm, called the primal–dual algorithm, by making good use of dual variables in addition to primal variables. Although its time complexity is the same as that of the primal algorithm, we can expect a better performance in practice. We finally consider an application to a computer vision problem called the panoramic image stitching.     

Development of Highly Sensitive Raman Spectroscopy for Subnano and Single-Atom Detection

Direct detection and characterisation of small materials are fundamental challenges in analytical chemistry. A particle composed of dozens of metallic atoms, a so-called subnano-particle (SNP), and a single-atom catalyst (SAC) are ultimate analysis targets in terms of size, and the topic is now attracting increasing attention as innovative frontier materials in catalysis science. However, characterisation techniques for the SNP and SAC adsorbed on substrates requires sophisticated and large-scale analytical facilities. Here we demonstrate the development of an ultrasensitive, laboratory-scale, vibrational spectroscopic technique to characterise SNPs and SACs. The fine design of nano-spatial local enhancement fields generated by the introduction of anisotropic stellate-shaped signal amplifiers expands the accessibility of small targets on substrates into evanescent electromagnetic fields, achieving not only the detection of isolated small targets but also revealing the effects of intermolecular/interatomic interactions within the subnano configuration under actual experimental conditions. Such a development of “in situ subnano spectroscopy” will facilitate a comprehensive understanding of subnano and SAC science.     

Epitaxial growth of isotactic polypropylene on oriented polyethylene from solution

Oriented polyethylene (PE) films with surfaces bounded by the (100) plane were prepared. On the film surfaces, isotactic polypropylene (iPP) was crystallized epitaxially from solution as quadrits with their sides parallel and perpendicular to the polyethylene chain axis. In the through wide-angle x-ray diffraction pattern (taken with incident x-rays normal to the polyethylene film surface), the 111 iPP reflections was observed on the meridian (Parallel to the polyethylene chain axis). In the edge patterns (taken with x-rays incident on the edge of the polyethylene film), 040 and 060 reflections were observed on the equator. From the diffraction patterns, the following lattice coincidence was observed between polyethylene and isotactic polypropylene: (010)iPP//(100) PE, [101]iPP//[001] PE. The Small-angle x-ray scattering patterns showed that edge-on isotactic polypropylene lamellae 9 nm thick were arranged with their long axes inclined at an angle of 40° from the polyethylene axis. Molecular chains were oriented within the lamellae normal to the surfaces.