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To identify the simplest organic structure for an emitter, we focused on 2,5-dimethoxybenzene-1,4-dicarboaldehyde. This symmetric molecule has a very low molecular weight (MW=194), a single benzene unit, and consists of only three elements (H, C and O). It forms highly efficient and pure emitting crystals (λem=499 nm, ΦF =0.42, FWHM=42 nm) due to the rigid structure based on the single benzene framework and four intramolecular hydrogen bonds between electron-donating methoxy and electron-accepting aldehyde groups. This crystal acts as a good optical waveguide with pure green emission (FWHM=34 nm) and very low loss coefficient (0.00120 dB/μm).

Commercially available 4,7-dibromo-2,1,3-benzothiadiazole can be used as a building block for the organic synthesis of high performance optoelectronics devices. Herein, we report that a single crystal of 4,7-dibromo-2,1,3-benzothiadiazole displays elastic bending flexibility and crystalline-state fluorescence. A large needle-shaped single crystal (over 1 cm long) exhibited a fibril lamella type structure based on slip-stacked (J-aggregated) molecular wires. The crystal was capable of bending under applied stress and quickly reverts to its original shape upon relaxation. The crystal shows a reversible fluorescence change via mechanical bending–relaxation that can be performed many times.

We investigated the relation between Sr# [= 100 Sr/(Sr + Ca) in mol] of calcites and their Raman spectra for Sr-doped calcite samples with Sr# of 0–13.2. We selected 3 major Raman peaks observed at 150–155 cm−1 (peak A), 274–282 cm−1 (peak B), and 710–712.5 cm−1 (peak C). With increasing Sr#, the peaks shifted monotonously to lower wavenumbers. We obtained a linear expression for peak B as Sr# = −1.734 ΔνB + 76.93, where ΔνB is a separation between peak B and a neon emission line of 237.07 cm−1 in Raman shift. The present spectroscopic analysis can ascertain Sr# of calcite with precision of ±1.26 in the range of Sr# of 0–13.2.

Organic single crystals with elastic bending flexibility are rare because they are generally brittle. We report here fluorescent organic single crystals based on thiophene-tetrafluorobenzene-thiophene derivatives, mainly 1,4-bis(thien-2-yl)-2,3,5,6-tetrafluorobenzene. Three derivatives were synthesized by Pd-catalyzed cross-coupling reactions (Stille or direct arylation pathways). The crystallization of the derivatives gave large (mm- or cm-scale) crystals. Two crystals of 1,4-bis(thien-2-yl)-2,3,5,6-tetrafluorobenzene, 1, and 1,4-bis(4-methylthien-2-yl)-2,3,5,6-tetrafluorobenzene, 3, bent under applied stress and quickly recovered its original shape upon relaxation. The other crystal of 1,4-bis(5-methylthien-2-yl)-2,3,5,6-tetrafluorobenzene, 2, showed brittle breakage under applied stress (normal behavior). Fibril lamella crystal structure based on criss-cross packed slip-stacked molecular wires and its structural integrity are important factors for the design and production of next generation crystal materials with elastic bending flexibility. Furthermore, mechanical bending–relaxation resulted in reversible change of the morphology and fluorescence (mechanofluorochromism). Such bendable crystals would lead to the next generation solid-state fluorescent and/or semiconducting materials.

The most stable sorption site of dimethyl ether on silicalite-1 is the sinusoidal channel. The configuration of guest molecules (linear or bent) plays an important role in determining where the stable sorption site is situated., The adsorption structures of dimethyl ether (DME) on silicalite-1 zeolite (MFI-type) are determined using single-crystal X-ray diffraction. The structure of low-loaded DME-silicalite-1 indicates that all DME molecules are located in the sinusoidal channel, which is the most stable sorption site based on the van der Waals interaction between DME and the framework. The configuration of guest molecules (linear or bent) plays an important role in determining where the stable sorption site is in the pore system of MFI-type zeolites. Bent molecules favor the sinusoidal channel, while linear molecules favor the straight channel. The contribution of DME–DME interactions is considerable in the high-loaded DME-silicalite-1 structure.

The process of CO2 adsorption on silicalite-1 zeolite (MFI-type) is revealed using a single-crystal X-ray method. The structure of CO2-silicalite-1 with a small amount of CO2 in the pore is determined, wherein most of CO2 molecules are located in the straight channel. It indicates the straight channel is the most stable sorption site based on the van der Waals interactions between the CO2 and the framework, and the CO2 molecules initially adsorb in the straight channel in the adsorption process. This is the first report to describe the structure of MFI-type zeolites with the adsorbate molecules occupying only the straight channel.

Structural analysis of CO2-silicalite-1 crystals using the single-crystal X-ray diffraction method reveals that the crystal system is twinned monoclinic. The structure of silicalite-1 (MFI-type zeolites) loaded with CO2 has previously been solved in orthorhombic system [1], but the R value is still large. Since CO2 molecules are too small to maintain the orthorhombic structure, it is considered that the CO2-silicalite-1 crystals should be in the relaxed monoclinic twin phase. The diffraction data in the previous report is recalculated in P21 /n as the monoclinic twinning.

The actual adsorption structures of non-aromatic hydrocarbons on the MFI-type zeolites have not yet been determined. This is due to the presence of twinning, which makes crystallographic analysis difficult. We recently overcame this problem, and now report the various adsorption structures of n-butane, n-pentane, n-hexane, 1-butene, cis and trans-2-butene, 2-butyne and isopentane on silicalite-1 (MFI-type zeolite) as determined via single-crystal X-ray diffraction. The structures were elucidated for both low and high loadings of each guest molecule in order to clarify the adsorption process. The low-loaded structures provide valuable insight into guest-framework interactions and initial adsorption behavior. The n-alkanes are initially adsorbed in the sinusoidal channel, while 2-butyne is adsorbed in the straight channel. In the case of the normal hydrocarbons, the molecular configuration (bent or linear) of the compound determines which channel is the preferred adsorption site. Bent molecules prefer the sinusoidal channel and linear molecules prefer the straight channel. In contrast, isopentane is initially adsorbed at the intersection, since the channels are too narrow to maintain the preferred distance between the framework and the bulky isopentane molecule. In the high-loaded structures, the guest molecules occupy additional sites, such that the normal hydrocarbons are located in both channels and isopentane is found at the intersection and the sinusoidal channel.

The location of physisorbed CO2 molecules on silicalite-1 zeolite (MFI-type) is determined using a single-crystal X-ray method. There are four sorption sites for CO2 molecules in the three-dimensional channel system of the silicalite-1. Two of them are in the straight channel in disorder (STR1 and STR2), while the other sites are in the sinusoidal channel (SIN) and at the intersection (INT). Their occupancy factors indicate that a large portion of the CO2 molecules are located in the straight channel. It is also revealed that the straight channel is the most favorable for CO2 molecules as sorption sites.

The adsorption process of phenol on silicalite-1 was studied by single-crystal X-ray diffraction. The loading of phenol on silicalite-1 was performed for 24, 48, 72, and 168 h. Phenol molecules first diffused through the intersection forming hydrogen bonds with the oxygen atoms of the framework and then subsequently turned into the sinusoidal channel. As adsorption progressed, phenol molecules were located at the intersection and in the sinusoidal channel, and these two kinds of phenols interacted with each other. High-loaded phenol–silicalite-1 (8.0 molecules/unit cell) was obtained after 168 h of adsorption. It is clear that hydrogen bonds were present in the framework, based on the results of the single-crystal XRD measurements and an IR study.

An orthorhombic benzene-silicalite-1 single crystal was obtained from a monoclinic twin crystal, and the structure was determined by a single-crystal method for the first time., A simple method for preparing orthorhombic single crystals of benzene-silicalite-1 was developed. A silicalite-1 crystal was pressed with a weight of 2 g along the +c and −c crystallographic axes while the temperature was increased to 473 K. The temperature was then slowly reduced to 313 K, and these heating and cooling steps were repeated three times. After the orthorhombic single crystals adsorbed benzene, the crystal structure of the resulting benzene-silicalite-1 was determined. There were two kinds of benzene molecules in the asymmetric unit. One was located at the intersection of the straight channels and the sinusoidal channels with the benzene ring parallel to the ac plane. The other benzene was located in the middle of the straight channel.

This study reports the first application of dynamic light scattering to observations of crystal growth of calcium carbonate from a supersaturated solution. Crystal size distributions around the cri...

Effects of l -aspartic acid ( l -Asp) on dissolution of calcite were investigated. The step retreat velocity and dissolution rate of calcite were measured simultaneously using an AFM flow-through system. The etch-pit morphology of calcite was observed using confocal laser scanning microscopy. Results show that the etch-pit morphologies changed drastically depending on the l -Asp concentration ([ l -Asp]) in the order of rhomboidal, pentagonal, and triangular (not perfectly, but retaining an extra step). The change in obtuse step directions and appearance of the [0 1 0] step triggered these morphological changes. Addition of l -Asp accelerated all step retreats at [ l -Asp] l -Asp on the diffusive barrier. In contrast, at [ l -Asp]>0.01 M, l -Asp inhibited the retreats of obtuse steps and [0 1 0] step, although the retreat velocities of acute steps were constant irrespective of [ l -Asp]. These results suggest that the directional changes and the inhibition of retreat velocities of obtuse steps were attributed to the generation of [ 4 1 1] and [4 5 1 ] steps caused by l -Asp. Moreover, we confirmed the preferential effects of l -Asp on the [4 8 1 ]+ to [ 4 4 1]± step edge, and proposed the preferential effects of l -Asp on the [ 4 1 1] to [4 5 1 ] step edge.

A simple method for preparing monoclinic single crystals of ZSM-5 is developed. The ZSM-5 crystals are pressed with a weight of 50 g at an angle of 45° relative to the b and c crystallographic axes of twin ZSM-5 crystals while the temperature is simultaneously increased to 573 K. The temperature is then slowly reduced to 313 K, and these steps are repeated three times. The monoclinic structure of the single crystals of ZSM-5 produced using this method is then determined.

〔目的〕本研究の目的は，静的ストレッチング（static stretching；SS）と動的ストレッチング（dynamic stretching；DS）後の関節可動域や筋出力に関して経時的変化を比較し，よりスポーツ活動前に適したストレッチング方法を明らかにすることとした。〔対象〕健康な成人女性18名とした。〔方法〕下腿三頭筋に対しSSおよびDSを行い，ストレッチング直前，直後，5分後，10分後に足関節背屈可動域と底屈筋力を測定した。〔結果〕関節可動域については，SSでは直後に上昇し10分間維持したのに対し，DS後は徐々に上昇し10分後にSS後と同程度に達した。筋力については，直後から10分後までSSよりもDSのほうが有意に高い値を示した。〔結語〕最大筋力を必要とするスポーツ活動の10分前にDSを行うことでより高いパフォーマンスを行うことができる可能性が示唆された。

The crystal structure of pollucite (ANA) (Cs,Na)AlSi2O6is characterized by single-crystal X-ray diffractometry. The space groupC2/c,monoclinic, is found to be the most probable space group for this mineral based on the systematic absences of reflections. Cesium ions or water molecules are disordered at the center of a channel and are slightly apart from the special position. This is the origin of symmetry breaking and the space group becomes lower fromIa-3d(analcime) toC2/c. Sodium ions or vacancies are located at the contact point of the channel. No ordering of aluminum is observed in the pollucite structure.

Single crystals of TPA-ZSM-5 were synthesized using KOH as a mineralizer instead of NaOH. The size of the TPA-ZSM-5 crystals after 120 h was approximately 100 μm. When KOH was used, the quantity of TPA-ZSM-5 crystals formed was increased, and Al distribution in the crystal was uniform. The form and quality of these crystals were suitable for single crystal X-ray diffraction. Nucleation of the analcime by-product, which is formed in the presence of NaOH, is inhibited when KOH is used, because the potassium ion does not act as a template for the analcime structure. Instead, zeolite W was observed as a by-product. However, compared to analcime, the amount of zeolite W was lower, and it was easier to separate from TPA-ZSM-5. Thus, potassium ions play an important role in the production of large quantities of high-quality ZSM-5 with a uniform Al distribution.

Impurity effects of trace lanthanum ion (La 3+ ) on the dissolution and growth of calcium carbonate were studied with in situ observation techniques. Dissolution kinetics of two polymorphs of calcium carbonate, calcite and vaterite, were investigated by monitoring the pH in the solution with laser-induced fluorescence spectroscopy using a pH-sensitive reagent, seminaphthorhodafluors. No effect on dissolution of vaterite was observed with the spectroscopic observations, whereas calcite dissolution was significantly inhibited by lanthanum ion with concentrations higher than 1 μM. Crystal growth and dissolution processes of calcite under the lanthanum-doped condition were observed by means of atomic force microscopy. Step propagations during crystal growth and dissolution of calcite were inhibited by trace lanthanum ion (5 μM). An insoluble thin layer of lanthanum carbonate deposited on the step site of the calcite surface could be a possible cause of the inhibitions observed both for dissolution and growth.

The entrance and diffusion pathway of CO2and dimethyl ether (DME) in MFI-type zeolite channels were investigated by a selective sealing method using large silicalite-1 crystals. The MFI-type zeolite has two kinds of orthogonal channels: straight channels and sinusoidal channels. The mouths of the straight channels are on (010) crystal faces, while those of the sinusoidal channels are on (100) faces. The channel mouths are directly sealed by silicone resin on the (100) and (010) faces so as to restrict the entrance and diffusion pathways to straight and sinusoidal channel pathways, respectively. The locations and loadings of the guest CO2and DME molecules are determined by single-crystal X-ray diffraction structural analysis. The loadings show the difference of the adsorption rates between the pathways. The straight channel pathway is 4.2 times faster than the sinusoidal channel pathway for the CO2, and the sinusoidal channel pathway is 5.1 times faster than the straight channel pathway for the DME. It reveals their dominant pathways and the anisotropy of adsorption. The dominant pathway correlates to the stability of the channel as adsorption sites.

The Fukushima nuclear accident has highlighted the importance of finding a better final storage method for radioactive cesium species. Cs is highly soluble in water, and can easily exchange with other alkali ions in zeolites or clays to form stable complexes. However, Cs(+) is released from Cs(+) complexes into water when surrounded by an excess of water. Pollucite may be the best final storage option for Cs(+), but its typical synthesis requires heating to about 1200 °C in air. Here, we show that the hydrothermal synthesis of pollucite can be completed at 300 °C in three hours from any zeolite or clay. Furthermore, our procedure does not require ion exchange before synthesis. Radioactive Cs is usually found in complexes with clays. At that time, this method only requires calcium hydroxide, water, and three hours of hydrothermal synthesis, so the process is both inexpensive and practical for large-scale application. Pollucite is an analog of analcime zeolite, and contains a channel system 2.8 A in diameter, which is formed by 6-oxygen rings. As the diameter of Cs(+) is 3.34 A and each Cs(+) exists independently within a separate portion of the channel, Cs(+) cannot exit the pollucite framework without breaking it.

A significant inhibiting effect was observed on the dissolution of calcite by addition of 5 μM lanthanum ion to the solution, whereas no inhibition was observed both for aragonite and vaterite under the same conditions. In situ AFM (atomic force microscopy) images suggested that micro-precipitates depositing at the step site of calcite inhibited the dissolution in the lanthanum-doped solution. The solubility-calculation for the given solution was consistent with lanthanum carbonate being the micro-precipitate.