Removal of residual images in parallel phase-shifting digital holography

Parallel phase-shifting digital holography (PPSDH) is a technique of single-shot phase-shifting digital holography. We found that there are two problems with this technique. (1) Some extraneous noises caused by the intensity unevenness of the reference wave become slightly superimposed on the object image. (2) The conjugate image cannot be completely removed. This is because the object wave causes the phase-shift error by illuminating an image sensor with a large incident angle. To solve these problems, we propose an algorithm for removing residual 0th-order diffraction and conjugate images in PPSDH. In the proposed algorithm, we modified phase-shifting interferometry in order to work through the unevenness of the intensity distribution and applied the Fourier transform technique to PPSDH to remove the residual conjugate image. The effectiveness of the proposed algorithm was experimentally verified.     

Acridine N-Heterocyclic Carbene Gold(I) Compounds: Tuning from Yellow to Blue Luminescence

The synthesis and the luminescence features of three gold(I)-N-heterocyclic carbene (NHC) complexes are presented to study how the n-alkyl group can influence the luminescence properties in the crystalline state. The mononuclear gold(I)-NHC complexes, [( L¹ )Au(Cl)] ( 1 ), [( L² )Au(Cl)] ( 2 ), and [( L³ )Au(Cl)] ( 3 ) were isolated from the reactions between [(tht)AuCl] and corresponding NHC ligand precursors, [N-(9-acridinyl)-N’-(n-butyl)-imidazolium chloride, ( L¹ .HCl)], [N-(9-acridinyl)-N’-(n-pentyl)-imidazolium chloride, ( L² .HCl)] and [N-(9-acridinyl)-N’-(n-hexyl)-imidazolium chloride, ( L³ .HCl)]. Their single-crystal X-ray analysis reveals the influence of the n-alkyl groups on solid-state packing. A comparison of the luminescence features of 1 – 3 with n-alkyl substituents is explored. The molecules 1 – 3 depicted blue emission in the solution state, while the yellow emission (for 1 ), greenish-yellow emission (for 2 ), and blue emission (for 3 ) in the crystalline phase. This paradigm emission shift arises from n-butyl to n-pentyl and n-hexyl in the crystalline state due to the carbon-carbon rotation of the n-alkyl group, which tends to promote unusual solid packing. Hence n-alkyl group adds a novel emission property in the crystalline state. Density Functional Theory and Time-Dependent Density Functional Theory calculations were carried out for monomeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride and dimeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride to understand the structural and electronic properties.     

Manipulating Slow Magnetic Relaxation by Light in a Charge Transfer {Fe2Co} Complex

Some cyanide-bridged complexes are known for exhibiting slow magnetic relaxation behavior in a light-induced metastable state. Herein, an unexpected reverse effect is observed for the first time in the S= {Fe^II_LS-Co^III_LS-Fe^III_LS} (HS=high spin, LS=low spin) ground state of a novel V-shaped trinuclear cyanide-bridged {Fe₂Co} complex. In this complex, light-switchable iron-cobalt charge transfer with repeatable off/on switching of slow magnetic relaxation is discovered upon alternating laser irradiation at 785 and 560 nm. An important characteristic of the present compound is that the S= ground state exhibits slow magnetic relaxation before irradiation, whereas this is accelerated after irradiation. This is different from the typical behavior, where the light-induced metastable state exhibits slow magnetic relaxation.     

Detection and evaluation of security features embedded in paper using spectral-domain optical coherence tomography

We propose a new method for authenticating valuable paper sheets such as gift coupons, tickets, and cheques with the use of optical coherence tomography (OCT). This method is based on the detection and evaluation of cross-sectional structural characteristics of valuable paper sheets provided with security features. Commonly used as a security feature is a security thread, which is embedded in such paper sheets. In this paper, the nondestructive detection of the embedded security thread is demonstrated using spectral-domain OCT. The results showed that the security thread was clearly visualized in the OCT image despite the highly scattering nature of papers.     

Pressure-induced structure change of molten KCl

Abstract

Energy-dispersive X-ray diffraction experiments of molten KCl under high pressure have been carried out by using synchrotron radiation. The diffraction profiles of molten KCl were acquired just above the melting temperature of KCl up to 4 GPa. The reduced structure factor S(Q)'s for molten KCl do not show any change in their primary features, except for a gradual increase in the first peak intensity with increasing pressure. This implies that molten KCl does not show a first-order phase transition, such as the B1-B2 transition, found in solid KCl, but that the local structure in molten KCl must be changed by compression. According to a molecular-dynamics simulation, this change of S(Q) can be explained by a continuous increase in the coordination number of the nearest-neighbor ions in molten KCl with pressure.     

Experimental Determination of a Third Derivative of G. (III): Differential Pressure Perturbation Calorimetry (II)

Earlier we constructed a differential pressure perturbation calorimeter, in order to determine directly a third derivative of the Gibbs energy G, the partial molar entropy-volume cross fluctuation density of solute B, ^SVd_[(B)\dot]^{\mathit{SV}}\delta_{\dot{\mathrm{B}}}, in a binary aqueous solution of B. Our attempt was basically successful, as described elsewhere (J. Solution Chem. 39:431–440, 2010). However, the uncertainty of the results for ^SV δ _B was several percent. One of the purposes of our direct experimental determination was to obtain a fourth derivative quantity graphically with some confidence. For this purpose, data of the third derivative quantity are necessary with uncertainties of less than one per cent. Various difficulties that we had on the first generation apparatus were attended to, and a new apparatus was constructed. The new experimental results for aqueous 2-butoxyethanol are found to be at least several-fold better. Hence, we were able to evaluate the fourth derivative quantity for the first time. The physical meaning of the fourth derivatives may become clearer in comparative studies when such data become available for aqueous solutions of other solutes including mono-ols and poly-ols. A project is underway to that effect.