Comparative analysis and quantitative evaluation of the field of view and the viewing zone of single-shot phase-shifting digital holography using space-division multiplexing

We comparatively analyzed and quantitatively evaluated the field of view and the viewing zone of single-shot phaseshifting digital holography that uses space-division multiplexing, for the first time. We formulated the sampling intervals in the techniques in which the phase of the reference wave is spatially divided into two and four steps, and numerically simulated the areas. It was clarified that each area of the spatial two-step phase-shifting technique was twice as wide as that of the spatial four-step phase-shifting technique. We also experimentally investigated the areas. The ghost appeared for the spatial four-step technique when the object was between the boundary of the field of view of the spatial two-step technique and that of the spatial four-step technique, but did not appear for the spatial two-step technique.     

High-speed phase imaging by parallel phase-shifting digital holography

Parallel phase-shifting digital holography can obtain three-dimensional information of a dynamically moving object with high accuracy by using space-division multiplexing of multiple holograms required for phase-shifting interferometry. We demonstrated high-speed parallel phase-shifting digital holography and obtained images of the phase variation of air caused by a compressed gas flow sprayed from a nozzle. In particular, we found the interesting phenomenon of periodic phase distributions. Reconstructed images were obtained at frame rates of 20,000 and 180,000 frames per second.     

Functionalization of cyclodextrins via reactions of 2,3-anhydrocyclodextrins

Three types of reactions of 2,3-anhydro-beta-cyclodextrins, namely nucleophilic ring-opening, reduction to 2-enopyranose, and reduction to 3-deoxypyranose, have been investigated to regio- and stereoselectively functionalize the secondary face of beta-cyclodextrin. Upon treatment with various nucleophiles, both 2,3-mannoepoxy and 2,3-alloepoxy-beta-cyclodextrins are found to undergo nucleophilic ring-opening reaction generating 3- and 2-modified cyclodextrin derivatives. In each case, the 3-position is more easily accessible than the 2-position. By using these ring-opening reactions, imidazolyl, iodo, azido, and benzylmercapto groups are selectively introduced to the secondary face of beta-cyclodextrin in place of the 2- or 3-hydroxyl groups. The functionalized cyclodextrins have either modified glucosidic subunits or modified altrosidic subunits that make the hydrophobic cavity slightly distorted from that of native beta-cyclodextrin. Thiourea also reacts with the cyclodextrin epoxides. In this case, thiirane and olefin species are generated instead of any ring-opening products. By ameliorating the reaction condition, cyclodextrin olefin, diene, and triene derivatives are prepared in moderate to good yields. Reduction of per[6-(tert-butyldimethyl)silyl]-beta-cyclodextrin permannoepoxide with lithium aluminum hydride produces the per(3-deoxy)-beta-cyclomannin. All these chemically modified cyclodextrins are structurally well characterized and most of them are expected to serve as versatile scaffolds for diverse purposes such as the construction of catalysts and development of synthetic receptors and molecular containers.     

Parallel two-step phase-shifting digital holography using polarization

We propose an optical implementation of a parallel two-step phase-shifting digital holography that utilizes a polarization technique. The implementation uses a phase-shifting array device consisting of a retarder array attached to an image sensor, and does not require the optical system to image the phase-shifting array device onto the image sensor required for the previously reported optical implementation of the parallel two-step phase-shifting digital holography. Then, the proposed implementation is essentially simple to align and compose. A preliminary experiment showed that the parallel two-step phase-shifting digital holography based on the proposed implementation can remove the conjugate image clinging to the image reconstructed by Fresnel transform alone with DC term suppression. Also, when the reconstruction distance was changed, the qualities of the reconstructed images were quantitatively evaluated by using normalized root-mean-square error. It was clarified that the proposed implementation was superior to other parallel phase-shifting digital holographies and Fresnel transform alone. Thus, the validity of the proposed implementation was confirmed.     

Cu-Catalyzed Desulfonylative Amination of Benzhydryl Sulfones

A new method for the synthesis of benzhydryl amines from the reaction of readily available sulfone derivatives with amines is described. The Cu-catalyzed desulfonylative amination not only provides structurally diverse benzhydryl amines in good yields, but is also applicable to iterative and intramolecular aminations. Control experiments suggested that the formation of a Cu-carbene intermediate generated from the sulfone substrate, which represents a new route for desulfonylative transformations.     

Broadband (1000 cm−1) multiplex CARS spectroscopy: Application to polarization sensitive and time-resolved measurements

A multiplex CARS spectrometer based on a cw diode-pumpedQ-switched Nd: YLF laser, a broadband dye-laser and a multichannel spectrum detection system has been constructed. Excellent mode characteristics of the laser beams and high pulse repetition rate (2 kHz) have resulted in good signal-to-noise ratio achieved with a few seconds accumulation time. A 1000 cm^–1 wide spectral range is covered in a single CARS spectrum with an expanded bandwidth of the dye laser. A thin-jet sampling method is used in order to avoid the phase-matching limitation. The efficient spectral intensity normalization by the reference (CCl₄) nonresonant spectrum and subsequent computer fitting have been implemented. The performance of the system is demonstrated by two different experiments. First, the polarization sensitive measurements (PS-CARS) of cyclohexane show its potential for accurate Raman depolarization ratio determination and for detection of weak (overlapped) Raman bands. Second, the transient resonance CARS measurement of the lowest excited triplet state of all-trans retinal indicate its feasibility to time-resolved CARS spectroscopy of fluorescent excited states.     

The adsorption of polyoxyethylated nonylphenol in cyclohexane solution

Summary The adsorption of polyoxyethylated nonylphenol on calcium carbonate and on carbon black in cyclohexane was studied and compared with that in water. The adsorption of this nonionic surfactant in cyclohexane on calcium carbonate showed a monolayer adsorption isotherm and that on carbon black showed a multilayer adsorption isotherm. The adsorption cross sectional area,A, of the surfactant molecule increased with the number of the ethylene oxide units,n, in both cases, and expressed by the equationsA=49.1n ^0.34 for the former case andA=270.n ^0.29 for the later case.When either one of the adsorbent or the solvent is polar and the other is nonpolar, the adsorbed molecules form simple oriented monolayer. When both of the adsorbent and the solvent are polar or nonpolar, however, the adsorption takes place in a complicated form and is delicately affected by the impurity and the balance of the polarity of the surfactant molecule.

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Zusammenfassung Die Adsorption von Polyoxyäthylen-nonylphenol an Calciumcarbonat und Ruß in Zyklohexan wurde untersucht und das Adsorptionsverhalten mit den Ergebnissen von wäßrigen Lösungen verglichen, die im letzten Bericht mitgeteilt sind. Die Adsorption dieser nichtionischen oberflächenaktiven Substanz in Zyklohexan an Calciumcarbonat zeigte eine monomolekulare und an Ruß eine höhermolekulare Adsorptionsisotherme. In beiden Fällen nahm der Adsorptionsquerschnitt,A, des oberflächenaktiven Moleküls mit der Anzahl der Äthylenoxid-Einheiten,n, zu, und es galten folgende Werte:A=49.1 n^0.29 im ersten Fall undA=270.n ^0.34 im letzten Fall.Die adsorbierten Moleküle bilden eine einfach orientierte monomolekulare Schicht, wenn von den beiden Komponenten Adsorbens oder Lösungsmittel eines polar und das andere unpolar ist. Wenn jedoch beide polar oder nichtpolar sind, verläuft die Adsorption komplizierter und wird von den Verunreinigungen und der Bilanz der Polarität empfindlich beeinflußt.

     

Site-selective guest inclusion in molecular networks of butadiyne-bridged pyridino and benzeno square macrocycles on a surface

We present here the formation of a modular 2D molecular network composed of two different types of square-shaped butadiyne-bridged macrocycles, having intrinsic molecular voids, aligned alternately at the solid-liquid interface. Site-selective inclusion of a guest cation took place at every other molecular void in the molecular network with two different recognition sites.