Giant Crystal Research Articles

Effects of soluble ions on hydration of calcined flue gas desulphurization gypsum

The influence of various water soluble cations (K+, Na+, Ca2+, Mg2+) on the hydration of calcined flue gas desulphurization gypsum was investigated. The results show that all cations but Ca2+ can accelerate the hydration of bassanite. The final crystal size is not largely influenced by different salts, except for Na+, where the giant crystal with length of >130 µm is observed. Current study clarifies the influence of different ions on the hydration of bassanite, which could provide sufficient guide for the pre-treatment of original flue gas desulphurization gypsum before actual application.

Structure Analysis and Derivation of Deformed Electron Density Distribution of Polydiacetylene Giant Single Crystal by the Combination of X-ray and Neutron Diffraction Data

The crystal structure of polydiacetylene giant single crystal has been analyzed on the basis of the two different methods of wide-angle neutron diffraction and X-ray diffraction. The X-ray result gives us the total electron density distribution [ρ(x)] of polymer chain. The neutron result tells the positions of atomic nuclei, which can allow us to speculate the electron density distributions [ρ0(x)] around the nonbonded isolated atoms. As a result, the so-called bonded (or deformed) electron density Δρ(x) [≡ ρ(x) – ρ0(x) = ρX(x) – ρN(x)], i.e., the electron density distribution due to the conjugation among the covalently bonded atoms along the polymer chain, can be estimated using the two information obtained by the X-ray and neutron data analyses (the so-called X-ray–neutron subtraction (X–N) method). The present report is the first example of the application of X–N method to the synthetic polymer species. The Δρ(x) derived for polydiacetylene was found similar to that of the low-molecular-weight model co...

What will be the future of the giant gypsum crystals of Naica mine?

Abstract The mine caves of Naica (Chihuahua, Mexico) are famous because they host large gypsum crystals. Mine works intersected new caves hosting the largest crystals in the world in the year 2000. From 2006 these caves became the object of a multidisciplinary research project with the goal of inferring their ages, the boundary conditions for their formation and the mechanisms inducing their development. Several other scientific aspects were also considered, including palynology, mineralogy, microbiology, physiology, hydrogeology and astrobiology. From 2006 to 2009, scientists and explorers tried to ensure the complete documentation of these natural wonders because they were expected to be accessible for only a few years. As a result of their location c. 160 m below the natural groundwater level, they were predicted to be flooded with thermal water as soon as dewatering of the mine ceased. This occurred at the end of 2015, so that the lower part of the mine is already submerged and in the near future the giant crystal caves will also disappear. Theoretically, it is still possible to maintain these incredible wonders for future generations, but this seems highly unlikely. Soon the crystals will be submerged below c. 150 m of hot water, restarting their incredible slow growth.

Creation of giant two-dimensional crystal of zinc oxide nanodisk by method of single-particle layer of organo-modified inorganic fine particles

In this study, the formation and structure of a single-particle layer of organo-zinc oxide are investigated using surface-pressure-area (π-A) isotherms, out-of-plane X-ray diffraction (XRD) analysis, and atomic force microscopy (AFM). Further, techniques for achieving the solubilization of inorganic fine particles in general solvents have been proposed, and a single-particle layer has been formed using such an inorganic solution as a “spreading solution” for an interfacial film. Surface modification of ZnO is performed using a long-chain carboxylic acid. Accordingly, a regular arrangement of ZnO can be easily achieved in order to overcome the relatively weak van der Walls interactions between inorganic materials. A condensed Langmuir monolayer of these particles is also formed. A multiparticle layered structure is constructed by the Langmuir–Blodgett (LB) technique. Out-of-plane XRD measurement results for a single-particle layer of organo-ZnO clearly show a sharp peak at 42Å. This peak is attributed to the distance between ZnO layers. The AFM image of this single-particle layer of organo-ZnO shows a particle assembly with a uniform height of 60nm. These aggregated particles form large two-dimensional crystals. In other words, a regular periodic structure along the c-axis and a condensed single-particle layer had been fabricated using Langmuir and LB techniques.

Giant MFI-type zeolite crystals prepared by bulk material dissolution method

Giant MFI-type zeolite crystals were synthesized by bulk material dissolution (BMD) method at 473 K employing tetrapropylammonium (TPAOH) as structure directing agent (SDA). The giant crystals were successfully grown up to 2.0 mm in the length direction. The SDA remaining in the crystals could be removed without serious damages to the crystals by a mild heat treatment. In this short paper, size change of giant crystal with process parameters and removal characteristics of SDA are reported.

Combinatory usage of X-ray and neutron diffraction techniques for the refined structure analysis of polymer crystals: From hydrogen atoms to bonded electron density distribution

In order to predict the physical property of polymers, we need to know the atomic coordinates including hydrogen atoms as accurately as possible. However, polymer samples give us limited number of broad X-ray reflections in general. In order to improve this problem, we have made many efforts to collect the X-ray diffraction data as accurate as possible. In this paper, we report the structure analysis including the extraction of hydrogen/deuterium atomic positions for the oriented polyoxymethylene by the combination of X-ray diffraction method with neutron diffraction method. In such a cases of polydiacetylene giant single crystal the bonded electron density distribution was evaluated along the skeletal chain by the so-called X-N method based on the wide-angle X-ray diffraction data and the wide-angle neutron diffraction data.

Formation and material properties of giant liquid crystal polymersomes

Polymersomes are vesicles made of amphiphilic diblock copolymers. Giant polymersomes of several tens of microns in diameter can be prepared from low Tg (glass transition temperature) flexible (coil-coil) copolymers by processes such as rehydration swelling or electroformation. These techniques are, however, inefficient in producing giant polymersomes composed of high Tg and/or rigid-flexible (rod-coil) copolymers. We have used an alternative method based on the formation of an inverted emulsion to produce giant unilamellar rod-coil polymersomes. We have selected copolymers whose hydrophobic moieties are glassy liquid crystalline polymers. The viscoelasticity of individual polymersomes has been measured by micropipette aspiration. Whereas the elastic modulus was found to be of the same order of magnitude as the one of prototypical vesicles made of coil-coil copolymers, the membrane viscosity of this new class of polymersomes was about three orders of magnitude more viscous than their coil-coil counterparts. The versatile method used here to form giant polymersomes could be useful for designing and studying novel functional polymer capsules. The results highlight the possibility of widely tuning the mechanical properties of polymersomes by selecting or synthesizing the proper copolymer.

Growth of Giant Two-Dimensional Crystal of Protein Molecules from a Three-Phase Contact Line

A novel method to fabricate a two-dimensional (2D) crystal of protein molecules has been developed. The method enables us to control both the position of nucleation and the direction of the crystal growth. The crystal obtained using a protein molecule, ferritin, was found to be composed of a number of densely packed single crystal domains with an unprecedentedly large size of approximately 100 microm(2). This method also reveals characteristic behavior of the spatiotemporal evolution of the crystal; for example, "fusion" of the crystal domains, which is never observed in an ordinary crystal composed of atoms or ions, was demonstrated. Our approach could have potential in fabricating extraordinarily large and highly ordered nanoparticle arrays of organic or inorganic materials.

3S3-4 昆虫飛翔筋 : 動くタンパク巨大単結晶(3S3 分子集合体になってはじめて発揮される機能〜筋肉収縮の場合〜,第46回日本生物物理学会年会)

3S3-4 昆虫飛翔筋 : 動くタンパク巨大単結晶(3S3 分子集合体になってはじめて発揮される機能〜筋肉収縮の場合〜,第46回日本生物物理学会年会)

Flight muscle myofibrillogenesis in the pupal stage ofDrosophilaas examined by X-ray microdiffraction and conventional diffraction

In the asynchronous flight muscles of higher insects, the lattice planes of contractile filaments are strictly preserved along the length of each myofibril, making the myofibril a millimetre-long giant single multiprotein crystal. To examine how such highly ordered structures are formed, we recorded X-ray diffraction patterns of the developing flight muscles of Drosophila pupae at various developmental stages. To evaluate the extent of long-range myofilament lattice order, end-on myofibrillar microdiffraction patterns were recorded from isolated quick-frozen dorsal longitudinal flight muscle fibres. In addition, conventional whole-thorax diffraction patterns were recorded from live pupae to assess the extent of development of flight musculature. Weak hexagonal fluctuations of scattering intensity were observed in the end-on patterns as early as approximately 15 h after myoblast fusion, and in the following 30 h, clear hexagonally arranged reflection spots became a common feature. The result suggests that the framework of the giant single-crystal structure is established in an early phase of myofibrillogenesis. Combined with published electron microscopy results, a myofibril in fused asynchronous flight muscle fibres is likely to start as a framework with fixed lattice plane orientations and fixed sarcomere numbers, to which constituent proteins are added afterwards without altering this basic configuration.

Visualization of elastic strain fields by the spatial distribution of the blue luminescence in a twinned microcline crystal

This paper correlates the mineralogical characteristics of twinning and exsolutions of a microcline giant crystal with macroscopic twin-domains and perthitic texture, taken from the Golconda III granitic pegmatite (Minas Gerais, Brazil), with the spatial distribution of the blue luminescence from radiation-induced O− defects. The twinning macrostructure and the Na distribution of the microcline have been studied by optical microscopy, backscattered electron scanning electron microscopy (SEM), chemical mapping and quantitative chemical analyses with electron microprobe. Spectra luminescence data were recorded by high sensitivity thermoluminescence, X-ray radioluminescence, cathodoluminescence (CL) and also CL-imaging under optical microscope at room temperature, and under SEM at liquid nitrogen temperature. The crystal recorded three different stages of re-equilibration during the geological cooling: (1) building up of regular macrostructures, formed mainly by only two Albite-twin law orientation variants, by solid-state domain self-assembly; (2) coarsening of one orientation variant at the expenses of the other by dissolution–reprecipitation reactions and (3) later degradation of regular twins into irregular domains. The spatial distribution of the blue luminescence in microcline can be used for two practical applications: (1) to mark water-rich fluid-flow channelways at low temperatures in which these light emissions are absent and (2) to visualize elastic strain fields across twin patterns, with maxima emission from the Na-rich (0 1 0) boundaries and remnants Pericline twin cores and minima from the Na-poor (0 1 0) twin cores and residual Pericline boundaries. Elastic strain must be the physical factor determining the radiation sensitivity of the lattice, i.e. radiation damage is not random in twinned lattices and defect formation occurs preferentially at the sites with high local elastic strain. Environmental ionizing radiation could involve a twofold effect during subsolidus microcline re-equilibration, i.e. Si/Al re-ordering, mainly acting on coherent twin boundaries, and also producing reactive \({\rm H}\raise0.145em\hbox{${\scriptscriptstyle \bullet}$} \) and \({\rm OH}\raise0.145em\hbox{${\scriptscriptstyle \bullet}$} \) radicals as radiolytic products of water.

Quantitative evaluation of stress distribution in bulk polymer samples through the comparison of mechanical behaviors between giant single‐crystal and semicrystalline samples of poly(trans‐1,4‐diethyl muconate)

AbstractThe Raman shift and crystallite modulus were measured under the application of tensile force for a giant single crystal and a series of uniaxially oriented semicrystalline samples of poly(trans‐1,4‐diethyl muconate) (polyEMU). The apparent Raman shift factor αapp or a vibrational frequency shift per 1 GPa tensile stress was higher for the semicrystalline samples with lower crystallinity or lower bulk modulus. The apparent crystallite modulus E or Young's modulus along the chain axis in the crystalline region was not constant but varied remarkably between the giant single crystal and semicrystalline samples. A systematic change in αapp and E among the polyEMU samples with different preparation history could be interpreted quantitatively on the basis of a mechanical series parallel model consisting of crystalline and amorphous phases. The origin of different E and αapp was speculated to be a stress concentration on the taut‐tie chain contained as a parallel crystalline component in the mechanical model. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 444–453, 2003

Vibrational Spectroscopic Study on the Molecular Deformation Mechanism of a Poly(trans-1,4-diethyl muconate) Single Crystal Subjected to Tensile Stress

A giant single crystal of poly(trans-1,4-diethyl muconate), obtained from the single crystal of the corresponding monomer by photoinduced solid-state polymerization reaction, was put under tension ...

Synthesis of a High-Quality Host Material: Zeolite MFI Giant Single Crystal from Monocrystalline Silicon Slice

Using monocrystalline silicon slice (MSS) as the silicon source, a high-quality zeolite MFI giant single crystal with the average size of 2 mm × 1 mm × 1 mm has been synthesized in the presence of F-. Experimental results show that the MFI giant single crystal in this work has a much larger size and better morphology than crystals synthesized in the traditional systems. The XRD patterns, the microphotographs, the crystallization curves, the thermogravimetric (TG) and differential thermal analysis (DTA), and the N2 adsorption measurements show that MSS is an effective silicon source for the synthesis of high-quality MFI giant single crystals. Meanwhile, strong visible photoluminescence (PL) of the Si-encapsulated zeolite MFI giant crystal at both room temperature and 10 K indicates that such a MFI giant single crystal is a fine host for the preparation of functional materials.

Heat capacity of a giant single crystal of C 60

The heat capacity of a giant single crystal of C 60 (8×6×6 mm 3) was measured from 6 to 350 K by adiabatic calorimetry. A very sharp first-order phase transition arising from the orientational ordering of C 60 molecules was observed at 262.1 K, and a glass transition due to freezing of the reorientational motion of C 60 molecules was also found at 84.6 K. The transition temperature and the height of the heat capacity peak are much higher than any other calorimetric results reported previously. The transition enthalpy and entropy are also large in comparison with the values determined hitherto for a powder sample. These facts reveal that the phase transition of C 60 is strongly affected by crystallinity as well as purity. The C 60 giant single crystal used here is supposed to be free from these effects. The present results may be considered as reference thermodynamic values and behavior for crystalline C 60.

合成高分子の結晶構造解析における最近の進歩

Recent development in the techniques for the X-ray structural analysis of synthetic polymer crystals have been reviewed with some illustrations. In particular the usefulness of imaging plate system has been stressed and a new software for collecting quantitative data of the position and integrated intensity of the observed reflections has been introduced, which enabled us to apply the so-called direct method to the construction of the initial structural models necessary for the structural refinement. The structural changes of polymer crystals caused by an application of tensile force or by a temperature change have been discussed for two cases of polydiacetylene giant crystal and orthorhombic polyethylene.

Preparation of C 60 single crystalline thin film by ionized cluster beam deposition and ion implantation into single crystalline C 60 thin film

We have succeeded in preparing single crystalline C 60 thin film of a lateral extension in the order of several millimeters on mica by ionized cluster beam (ICB) deposition. During the growth process, planar dendrite-like single crystalline islands were observed by an atomic force microscope (AFM). It was concluded from reflection high-energy electron diffraction (RHEED) and transmission electron diffraction (TED) analyses that these islands grow hetero-epitaxially on mica. As the deposition process continues, the single crystalline islands coalesce and finally form a giant single crystal without grain boundaries between the former islands. This layered dendrite-like crystal growth is considered to be due to the ICB process, namely, ionizing molecules and accelerating them. Furthermore, the effect of ion (P +, B +, Ar +) implantation into C 60 thin films on the molecular structure and the conductivity has been studied under various implantation conditions. It was found from the analyses of FT-IR and Raman spectroscopies that the soccer-ball-like structure of C 60 changes into a diamond-like carbon (DLC) structure with an implantation energy higher than 40 keV, whereas the structure undergoes virtually no change with 10 keV implantation. As for conductivity changes under the lower implantation energy condition, the minimum dose of P + ions required to increase the conductivity from the non-doped value (10 12 cm −2) is 10 times lower than in the case of Ar + implantation. The conductivity change for the P + implantation could be explained satisfactorily not only by the effect of chemically-modified C 60 but also by the effect of a charge-transfer state between C 60 and implanted ions. It was concluded from these results that the conductivity of the C 60 film can be controlled over a wide range based on the carrier generation mechanism, which depends on the implantation conditions.

The half-life of V 50

Examination of the gamma spectrum from 5 kg of spectrographically pure vanadium metal using a giant sodium iodide crystal indicates that naturally occuring V 50 decays by negaton emission and by electron capture with partial half-lives of 1.8±0.6×10 16 and 8.9±1.6×10 15 y, respectively. It is shown that the degree to which natural uranium and thorium occur in the source material must be accounted for in the measurement of very low specific activities. The importance of correcting for changes in the natural background spectrum shape caused by the different absorption for the cosmic radiation and local radioactivity in the pressence of large amounts of source material are discussed.