scholarly journals The 24-chain core-shell nanostructure of wood cellulose microfibrils in seed plants

2022 ◽  
Author(s):  
Chih-Hui Chang ◽  
Wenjie Cai ◽  
Jer-Horng Lin ◽  
Shing-Jong Huang ◽  
Ying-Chung Jimmy Lin ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Area Measurement ◽  
Cellulose Microfibrils ◽  
X Ray Diffraction ◽  
Wood Cellulose ◽  
X Ray ◽  
Saxs Measurement ◽  
X Ray Scattering ◽  
Glucan Chain ◽  
Average Wood

Wood cellulose microfibrils (CMFs) are the most abundant organic substance on earth, but their nanostructures are poorly understood. There are controversies regarding the glucan chain number (N) of CMFs during initial synthesis and whether they become fused afterwards. Here, we combined small-angle X-ray scattering (SAXS), solid-state nuclear magnetic resonance (ssNMR) and X-ray diffraction (XRD) analyses to resolve these controversies. We successfully developed SAXS measurement methods for the cross-section aspect ratio and area of the crystalline-ordered CMF core, which showed higher density than the semi-disordered shell. The 1:1 aspect ratio suggested that CMFs remain mostly segregated, not fused. The area measurement revealed the chain number in the core zone (Ncore). The ratio of ordered cellulose over total cellulose, termed Roc, was determined by ssNMR. Using the formula N = Ncore / Roc, we found that the majority of wood CMFs contain 24 chains, conserved between gymnosperm and angiosperm trees. The average wood CMF has a crystalline-ordered core of ~2.2 nm diameter and a semi-disordered shell of ~0.5 nm thickness. In naturally and artificially aged wood, we only observed CMF aggregation (contact without crystalline continuity) but not fusion (forming conjoined crystalline unit). This further argued against the existence of partially fused CMFs in new wood, overturning the recently proposed 18-chain fusion hypothesis. Our findings are important for advancing wood structural knowledge and more efficient utilization of wood resources in sustainable bio-economies.

In Situ Synchrotron SAXS/WAXD Study during Uniaxial Drawing of Poly (L-Lactic Acid)

2014 ◽  
Vol 1048 ◽  
pp. 404-409
Author(s):  
Takahiko Kawai ◽  
Shin-ichi Kuroda
Keyword(s):  
Lactic Acid ◽  
Mechanical Response ◽  
Early Stage ◽  
Amorphous Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saxs Measurement ◽  
X Ray Scattering ◽  
Shish Structure

The structure development of poly (L-lactic acid)(PLLA) during the uniaxial drawing was investigated by means of in-situ simultaneous wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) measurements. When the quenched amorphous film of PLLA was drawn at 77.2 oC, which was well above the glass transition temperature of PLLA, two different crystal structures were formed depending on the strain. The mesophase, which has 103 helix with large amount of packing disorder, was formed at the early stage of drawing, followed by the crystal transformation into α’ form (ε ≥ 1.5). SAXS measurement showed that the kebab formation begins at the stage later than that of meso-α’ transition. It strongly suggests that the transition takes place inside the shish structure. The development of kebab leads to the enhancement of mechanical response, which is found to be the origin of the strain hardening of PLLA.

New Structure of CTAB Templated Silica Films as revealed by GISAXS coupled to HRTEM

2000 ◽  
Vol 628 ◽  
Author(s):  
Sophie Besson ◽  
Catherine Jacquiod ◽  
Thierry Gacoin ◽  
André Naudon ◽  
Christian Ricolleau ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Grazing Incidence ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Silica Films ◽  
X Ray ◽  
X Ray Scattering ◽  
Hexagonal Arrangement ◽  
Spherical Micelles

ABSTRACTA microstructural study on surfactant templated silica films is performed by coupling traditional X-Ray Diffraction (XRD) and Transmission Electronic Microscopy (TEM) to Grazing Incidence Small Angle X-Ray Scattering (GISAXS). By this method it is shown that spin-coating of silicate solutions with cationic surfactant cetyltrimethylammonium bromide (CTAB) as a templating agent provides 3D hexagonal structure (space group P63/mmc) that is no longer compatible with the often described hexagonal arrangement of tubular micelles but rather with an hexagonal arrangement of spherical micelles. The extent of the hexagonal ordering and the texture can be optimized in films by varying the composition of the solution.

scholarly journals X-ray and Neutron Study on the Structure of Hydrous SiO2 Glass up to 10 GPa

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 84 ◽  
Author(s):  
Satoru Urakawa ◽  
Toru Inoue ◽  
Takanori Hattori ◽  
Asami Sano-Furukawa ◽  
Shinji Kohara ◽  
...  
Keyword(s):  
Oxide Glasses ◽  
Void Space ◽  
X Ray Diffraction ◽  
Amorphous Sio2 ◽  
Sio2 Glass ◽  
X Ray ◽  
X Ray Scattering ◽  
Medium Range ◽  
Two Phases ◽  
A Minor

The structure of hydrous amorphous SiO2 is fundamental in order to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO2 glass with 13 wt.% D2O was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into two phases: a major phase rich in SiO2 and a minor phase rich in D2O molecules distributed as small domains with dimensions of less than 100 Å. Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO2 glass by disruption of SiO4 linkage due to the formation of Si–OD deuterioxyl, while the response of its structure to pressure is almost the same as that of the anhydrous SiO2 glass. Most of D2O molecules are in the small domains and hardly penetrate into the void space in the ring consisting of SiO4 tetrahedra.

Efficient adsorption of chlorpyrifos onto modified activated carbon by gamma irradiation; a plausible adsorption mechanism

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed S. Yahia ◽  
Ahmed S. Elzaref ◽  
Magdy B. Awad ◽  
Ahmed M. Tony ◽  
Ahmed S. Elfeky
Keyword(s):  
Gamma Irradiation ◽  
Area Measurement ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Pseudo First Order ◽  
Kinetics Of

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.

Comparative Studies of Ultra Low-κ Porous Silica Films with 2-D Hexagonal and Disordered Pore Structures

2004 ◽  
Vol 812 ◽  
Author(s):  
Nobutoshi Fujii ◽  
Kazuhiro Yamada ◽  
Yoshiaki Oku ◽  
Nobuhiro Hata ◽  
Yutaka Seino ◽  
...  
Keyword(s):  
Pore Structure ◽  
Nonionic Surfactants ◽  
Porous Silica ◽  
Silica Film ◽  
X Ray Diffraction ◽  
Silica Films ◽  
X Ray ◽  
X Ray Scattering ◽  
Porous Silica Film ◽  
Diffraction Peaks

AbstractPeriodic 2-dimensional (2-D) hexagonal and the disordered pore structure silica films have been developed using nonionic surfactants as the templates. The pore structure was controlled by the static electrical interaction between the micelle of the surfactant and the silica oligomer. No X-ray diffraction peaks were observed for the disordered mesoporous silica films, while the pore diameters of 2.0-4.0 nm could be measured by small angle X-ray scattering spectroscopy. By comparing the properties of the 2-D hexagonal and the disordered porous silica films which have the same porosity, it is found that the disordered porous silica film has advantages in terms of the dielectric constant and Young's modulus as well as the hardness. The disordered porous silica film is more suitable for the interlayer dielectrics for ULSI.

Time-resolved isothermal crystallization of absorbable PGA-co-PLA copolymer by synchrotron small-angle X-ray scattering and wide-angle X-ray diffraction

Polymer ◽  
2001 ◽  
Vol 42 (21) ◽  
pp. 8965-8973 ◽  
Author(s):  
Zhi-Gang Wang ◽  
Xuehui Wang ◽  
Benjamin S. Hsiao ◽  
Saša Andjelić ◽  
Dennis Jamiolkowski ◽  
...  
Keyword(s):  
Small Angle ◽  
Isothermal Crystallization ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

An X-ray scattering study on inverted Ge–Si huts grown at low temperatures

2004 ◽  
Vol 19 (4) ◽  
pp. 347-351
Author(s):  
J. Xu ◽  
X. S. Wu ◽  
B. Qian ◽  
J. F. Feng ◽  
S. S. Jiang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Lattice Strain ◽  
Lattice Mismatch ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Large Lattice ◽  
Scattering Study

Ge–Si inverted huts, which formed at the Si∕Ge interface of Si∕Ge superlattice grown at low temperatures, have been measured by X-ray diffraction, grazing incidence X-ray specular and off-specular reflectivities, and transmission electron microscopy (TEM). The surface of the Si∕Ge superlattice is smooth, and there are no Ge–Si huts appearing on the surface. The roughness of the surfaces is less than 3 Å. Large lattice strain induced by lattice mismatch between Si and Ge is found to be relaxed because of the intermixing of Ge and Si at the Si∕Ge interface.

A high-throughput assembly of beam-shaping channel-cut monochromators for laboratory high-resolution X-ray diffraction and small-angle X-ray scattering experiments

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Peter Nadazdy ◽  
Jakub Hagara ◽  
Petr Mikulik ◽  
Zdenko Zaprazny ◽  
Dusan Korytar ◽  
...  
Keyword(s):  
High Resolution ◽  
Small Angle ◽  
Photon Flux ◽  
Photon Flux Density ◽  
X Ray Diffraction ◽  
High Beam ◽  
X Ray ◽  
X Ray Scattering ◽  
Beam Collimation ◽  
Ray Scattering

A four-bounce monochromator assembly composed of Ge(111) and Ge(220) monolithic channel-cut monochromators with V-shaped channels in a quasi-dispersive configuration is presented. The assembly provides an optimal design in terms of the highest transmittance and photon flux density per detector pixel while maintaining high beam collimation. A monochromator assembly optimized for the highest recorded intensity per detector pixel of a linear detector placed 2.5 m behind the assembly was realized and tested by high-resolution X-ray diffraction and small-angle X-ray scattering measurements using a microfocus X-ray source. Conventional symmetric and asymmetric Ge(220) Bartels monochromators were similarly tested and the results were compared. The new assembly provides a transmittance that is an order of magnitude higher and 2.5 times higher than those provided by the symmetric and asymmetric Bartels monochromators, respectively, while the output beam divergence is twice that of the asymmetric Bartels monochromator. These results demonstrate the advantage of the proposed monochromator assembly in cases where the resolution can be partially sacrificed in favour of higher transmittance while still maintaining high beam collimation. Weakly scattering samples such as nanostructures are an example. A general advantage of the new monochromator is a significant reduction in the exposure time required to collect usable experimental data. A comparison of the theoretical and experimental results also reveals the current limitations of the technology of polishing hard-to-reach surfaces in X-ray crystal optics.

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