This review examines the effects of thermal vibrations on core-level excitation spectra, with a particular emphasis on the Ti L2,3-edge spectra of cubic perovskite-type titanium oxides (SrTiO3 and PbTiO3). Based on combining scanning transmission electron microscopy energy-loss near-edge structure analyses with cluster-type crystal-field multiplet calculations, the influence of atomic thermal vibrations on the fine structure of the Ti L2,3-edge is investigated, and it is demonstrated that the thermal vibration of oxygen atoms in cubic SrTiO3 can be estimated from the spectrum by fitting experimental and theoretical results. The same approach was extended to cubic PbTiO3 such that isotropic thermal vibrations were identified that relate to the difference in the transition to a low-temperature tetragonal phase. Although the present technique does not directly resolve phonon modes, it treats thermal factors as adjustable parameters, enabling the identification of subtle vibrational features even in materials already widely studied. Further investigation of the relationship between thermal vibrations and the fine structure of core-loss spectra could assist in elucidating certain material properties.

This review examines the effects of thermal vibrations on core-level excitation spectra, with a particular emphasis on the Ti L2,3-edge spectra of cubic perovskite-type titanium oxides (SrTiO3 and PbTiO3). Based on combining scanning transmission electron microscopy energy-loss near-edge structure analyses with cluster-type crystal-field multiplet calculations, the influence of atomic thermal vibrations on the fine structure of the Ti L2,3-edge is investigated, and it is demonstrated that the thermal vibration of oxygen atoms in cubic SrTiO3 can be estimated from the spectrum by fitting experimental and theoretical results. The same approach was extended to cubic PbTiO3 such that isotropic thermal vibrations were identified that relate to the difference in the transition to a low-temperature tetragonal phase. Although the present technique does not directly resolve phonon modes, it treats thermal factors as adjustable parameters, enabling the identification of subtle vibrational features even in materials already widely studied. Further investigation of the relationship between thermal vibrations and the fine structure of core-loss spectra could assist in elucidating certain material properties.

Understanding individual electronic orbitals involved in chemical bonding through scanning transmission electron microscopy and electron energy loss spectroscopy is essential for advancing materials science. Although previous theoretical and experimental results show the anisotropic image contrast of the corresponding particular final-state, the interpretation of these contrasts remain unclear. Here, we demonstrate the experimental anisotropic atomic contrast in the mapping of the fine structure of the O K-and Ti L2,3-edges of rutile TiO2, and propose a qualitative theoretical explanation. Our results revealed that the contrast does not directly reflect the electron density of the final state orbital, but rather the direction in which the selected transition matrix element is reflected. And its direction sometimes corresponds to that of selected orbital but not always so. The proposed interpretation method would be used for the analysis of future experimental data.

Biomolecular condensates, also known as membraneless organelles, play a crucial role in cellular organization by concentrating or sequestering biomolecules. Despite their importance, synthetically mimicking these organelles using non-peptidic small organic molecules has posed a significant challenge. The present study reports the discovery of D008, a self-assembling small molecule that sequesters a unique subset of RNA-binding proteins. Analysis and screening of a comprehensive collection of approximately 1 million compounds in the Chinese National Compound Library (Shanghai) identified 44 self-assembling small molecules in aqueous solutions. Subsequent screening of the focused library, coupled with proteome analysis, led to the discovery of D008 as a small organic molecule as a small organic molecule with the ability to condensate a specific subset of RNA-binding proteins. In vitro experiments demonstrated that the D008-induced sequestration of RNA-binding proteins impeded mRNA translation. D008 may offer a unique opportunity for studying the condensations of RNA-binding proteins and for developing an unprecedented class of small molecules that control gene expression.

This chapter describes the basics of transmission electron microscopy. After a brief description of the instrumentation, the fundamental physics of fast electron-matter interactions is presented to explain the principles of electron diffraction and imaging. For high-resolution image observations, crystal structure imaging by phase contrast of a transmission electron microscope and high-angle annular dark-field imaging, which is incoherent imaging by a scanning transmission electron microscope, are introduced.

Materials that intrinsically exhibit localized surface plasmon resonance (LSPR) in the visible region have been predominantly researched on nanoparticles (NPs) composed of coinage metals, namely Au, Ag, and Cu. Here, as a coinage metal-free intermetallic NPs, colloidal PtIn2 NPs with a C1 (CaF2 -type) crystal structure are synthesized by the liquid phase method, which evidently exhibit LSPR at wavelengths similar to face-centered cubic (fcc)-Au NPs. Computational simulations pointed out differences in the electronic structure and photo-excited electron dynamics between C1-PtIn2 and fcc-Au NPs; reduces interband transition and stronger screening with smaller number of bound d-electrons compare with fcc-Au are unique origins of the visible plasmonic nature of C1-PtIn2 NPs. These results strongly indicate that the intermetallic NPs are expected to address the development of alternative plasmonic materials by tuning their crystal structure and composition.

The difference in the thermal vibration of oxygen in the cubic perovskites PbTiO3 and SrTiO3 was explored by associating it with their phase transitions at low temperatures. The thermal vibration factor for oxygen in cubic PbTiO3 was estimated by employing an indirect approach that combines experimental Ti L2,3-edge electron energy-loss spectroscopy and crystal field multiplet calculations incorporating atomic vibrations. The results uncovered relatively isotropic vibration behavior in PbTiO3 and strong anisotropy in SrTiO3, despite their identical lattice parameters at different temperatures. Specifically, similar vibration factors along the Ti-O bond were estimated for both materials, whereas the amplitude of oxygen vibration in the A-O plane for PbTiO3 was significantly smaller than that for SrTiO3. This larger oxygen vibration in the A-O plane of SrTiO3 can be attributed to the existence of the rotational phonon mode, contributing to a TiO6 octahedron rotational phase transition at low temperature due to softening of the R25 mode. Therefore, the smaller vibration amplitude for oxygen in PbTiO3 could possibly be attributed to the intrinsic small rotational phonon mode, leading to a zone-center displacement-type phase transition induced by a softened I'15 mode. Further, the charge density map obtained by density functional theory calculation proposes a broader valence electron distribution for Pb2+ compared to Sr2+ and greater electron repulsion between Pb and O, potentially contributing to smaller oxygen vibration in the Pb-O plane of PbTiO3. This research provides valuable insights into the role of vibrational behavior in phase transition mechanisms, and offers the potential to predict the phase transition types for perovskites in the high-temperature cubic paraelectric phase.

Bronze phase titanium dioxide (TiO2(B)) nanorods were successfully prepared via a hydrothermal method together with an ion exchange process and calcination by using anatase titanium dioxide precursors in the alkali hydrothermal system. TiO2 precursors promoted the elongation of nanorod morphology. The different hydrothermal temperatures and reaction times demonstrated that the synthesis parameters had a significant influence on phase formation and physical morphologies during the fabrication process. The effects of the synthesis conditions on the tailoring of the crystal morphology were discussed. The growth direction of the TiO2(B) nanorods was investigated by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The as-synthesized TiO2(B) nanorods obtained after calcination were used as anode materials and tested the efficiency of Li-ion batteries. This research will study the effects of particle morphologies and crystallinity of TiO2(B) derived from a modified hydrothermal method on the capacity and charging rate of the Li-ion battery. The TiO2(B) nanorods, which were synthesized by using a hydrothermal temperature of 220 °C for 12 h, presented excellent electrochemical performance with the highest Li storage capacity (348.8 mAh/g for 100 cycles at a current density of 100 mA/g) and excellent high-rate cycling capability (a specific capacity of 207.3 mAh/g for 1000 cycles at a rate of 5000 mA/g).

Hematite ( a -Fe 2 O 3 ) nanowhiskers (NWs) synthesized via oxidation of iron-based substrates are a promising photoanode material for photoelectrochemical water splitting. Such synthesized a -Fe 2 O 3 NWs have been found to contain ordered axial structures. Herein, we reveal that the known (112)-related ordered structure actually exists in bicrystalline a -Fe 2 O 3 NWs instead of single-crystalline a -Fe 2 O 3 NWs and that it is associated with another known (330)-related ordered structure. Through a spherical aberration (C S )-corrected high-resolution transmission electron microscopy (HR-TEM) investigation, the microstructural characteristic of the (112)-related ordered structure is verified to be periodic atomic column displacements serving as tensile strain accommodation. The HR-TEM observation are also supported by a monochromated O K-edge EELS analysis, which indicates that a -Fe 2 O 3 NWs hosting the (112)-related ordered structure are indeed associated with lattice expansion. In sum, our microstructural study elucidates the root cause of the long-asserted relationship between the (112)-related ordered structure and oxygen vacancy ordering.

High-angle annular dark-field (HAADF) imaging and elemental mapping at the atomic scale by scanning transmission electron microscopy (STEM) combined with electron energy-loss spectroscopy (EELS) are widely used for material characterization, in which quantitative understanding of the contrast of the image is required. Here, we report an unexpected image contrast in the elemental mapping of rutile TiO2, where the Ti L2,3 map shows an anisotropic elliptical shape that extends along the long axis in the octahedral structure, while the atomic contrast of Ti columns in the HAADF image is almost circular. Multi-slice simulation reveals that unique electron channeling related to the rutile structure and the difference of the potentials between HAADF and EELS cause the different atomic contrasts in the two images.

Phase identification and the microstructure of carbide phases present in annealed 28 wt% Cr-2.6 wt% C high chromium cast irons with the addition of Mo or W have been characterized using optical microscopy, scanning electron microscopy, X-ray diffraction and transmission electron microscopy. Electron energy-loss spectroscopy was also used to identify M7C3 and M23C6 carbides in these irons. Annealing was performed by holding at the temperature of 800 degrees C for 4 h, followed by slow cooling at 20 degrees C/s to 500 degrees C, and then furnace cooling. Multiple eutectic carbides including, M23C6 and M6C were observed in the as-cast iron containing 1.42 wt% Mo. In contrast, the addition of 0.99 wt% W led to the change from hypoeutectic to hypereutectic iron and only M7C3 carbide was found in the as-cast condition. The post-annealing microstructures of all irons contained eutectic carbides, coarse secondary carbides next to the eutectic carbides, fine secondary carbide precipitated within the ferrite matrix, and some lamellar pearlite at the central areas of prior austenite dendrites. The results of TEM observation via selected-area electron diffraction and energy-dispersive X-ray spectrometry confirmed that the coarse and fine secondary carbides and lamellar pearlitic carbides, formed during the annealing treatment, were M23C6 carbide. In addition, the fine structures in C K-edge spectra were found to be useful for distinguishing between M7C3 and M23C6 carbides.

In this work, water hyacinth stem waste was used as a cost-effective and sustainable precursor to synthesize carbon/iron oxide (C/FeOx) nanocomposite anode materials, which were simultaneously produced in one step of catalytic graphitization. The synthesis process was superior in terms of simplicity, scalability, simplicity of required conditions, and environmental friendliness. Intensive physical characterization revealed that the synthesized materials consisted of FeOx nanoparticles and salt contents scattered across the surface of partially graphitized carbon. This was greatly advantageous since carbon would be able to suppress the volume change effect of FeOx. As a result, electrochemical studies discovered that the C/FeOx nanocomposite with the best performance delivered a high reversible capacity of 268.5 mAh g−1 after 300 cycles at 0.1 A g−1 and 171.1 mAh g−1 after 1000 cycles at 2 A g−1. Even after cycling through 5000 cycles at a fast charge stage of 10 A g−1, this material could still function as a great anode. Also, the coulombic efficiency was found to be greater than 90

The atomic vibration factor is commonly measured by diffraction experiments. However, it is difficult to estimate the accurate value from the powdered sample, particularly in anisotropic vibration cases. Here, we demonstrate an alternate method to extract anisotropic atomic vibration factors for oxygen in SrTiO3 using the monochromated Ti L-2,L-3-edge electron energy-loss spectrum measured by scanning transmission electron microscopy combined with crystal field multiplet calculation including anisotropic vibration effects. First, we theoretically investigated the effects of individual elemental thermal vibration on the Ti L-2,L-3-edge spectrum. This reveals that only atomic vibration of O mainly affects the spectral shape with sensitivity while the effects of that of Ti and Sr are very small. Thus, we extract the anisotropic atomic vibration factor of oxygen from experimental L-2,L-3-edge spectra by estimating with calculated ones. As a result, this demonstrates that the estimated temperature-dependent anisotropic atomic vibration factors for oxygen in SrTiO3 show good agreement with previously reported experiments and theoretical values. The investigation of atomic vibration at the atomic scale would be useful for further understanding of thermal properties of functional materials.

The microscopic effects of He irradiation on the H isotope retention in W were quantitatively evaluated using two types of high-function transmission electron microscopes: an ion-gun directly coupled TEM equipped with a high-resolution quadrupole mass spectrometer and an aberration-corrected scanning TEM combined with electron energy-loss spectrometer (STEM-EELS). He pre-irradiation induced fine and dense bubbles near the surface of the samples, thereby significantly increasing the deuterium (D) retention. The STEM-EELS analysis revealed that most of the D atoms were trapped and distributed homogeneously in the bubbles and released at relatively low temperatures without microstructural changes with increasing temperature. In contrast, some of the He was dissociated from the bubble by D post-irradiation in the matrix with a metastable state and retrapped by the bubble as the temperature was increased.

Beryllium (Be) has been selected as the plasma-facing material and a neutron multiplier in ITER. Be is exposed to burning plasma, and helium (He) bubbles are formed and grow. Understanding bubble behavior is crucial because it affects material properties. In this study, the internal pressure and growth behaviors of He bubbles in Be were investigated using in situ transmission electron microscopy (in situ TEM) and scanning transmission electron microscopy combined with electron energy loss spectroscopy (STEM-EELS). It was experimentally examined that the bubble shape, the bubble thickness, and the internal pressure of He bubbles using STEM-EELS. The internal pressure of the spherical He bubbles was higher than that of faceted He bubbles. In situ TEM observation of bubble behaviors under annealing at approximately 973 K showed that the growth rates of spherical He bubbles were higher than those of faceted bubbles. In situ TEM observations indicated that the Brownian motion of the He bubbles depended on their shape. Consequently, the spherical He bubbles with high pressure in Be facilitated bubble growth owing to their high mobility.

An infinite number of crystal structures in a multicomponent alloy with a specific atomic ratio can be devised, although only thermodynamically-stable phases can be formed. Here, we experimentally show the first example of a layer-structured pseudo-binary alloy, theoretically called Z3-FePd3. This Z3 structure is achieved by adding a small amount of In, which is immiscible with Fe but miscible with Pd and consists of an alternate L10 (CuAu-type)-PdFePd trilayer and Pd-In ordered alloy monolayer along the c axis. First-principles calculations strongly support that the specific inter-element miscibility of In atoms stabilizes the thermodynamically-unstable Z3-FePd3 phase without significantly changing the original density of states of the Z3-FePd3 phase. Our results demonstrate that the specific inter-element miscibility can switch stable structures and manipulate the material nature with a slight composition change.

The noise performance and the detection limits of a direct-counting complementary metal-oxide semiconductor (CMOS) K2 camera and a charge-coupled device (CCD) camera in electron energy loss spectroscopy (EELS) experiments were evaluated. In the case of a single spectrum acquired at the shortest dwell times (2.5 ms for K2 and 1 μs for CCD), the detection limit, defined as three times the standard deviation of the spectral noise (3σ), was very low (1 e−/channel) in the counting-mode spectrum acquired with the K2 camera compared with that acquired with the CCD camera (5 e−/channel). By contrast, the spectral noise of the K2 camera changed depending on the dwell time because of the multiple read-outs related to its fixed frame rate (400 fps). The spectral noise of the K2 camera was greater than that of the CCD camera when the dwell time was longer than ∼30 ms. Thus, the CCD camera was found to still be useful when detecting a very small number of electrons using a long acquisition time. In the case of an accumulated spectrum obtained by acquiring 10,000 spectra after subtracting the ultra-high-quality dark reference signal, the detection limits per read-out were ∼0.016 and ∼0.025 e−/channel/read-out for the K2 and CCD cameras, respectively. Because both cameras have advantages and disadvantages with respect to their detection limit, speed, and dynamic range, their proper use is important.

Anthrylene-and ferrocenoyl-assisted composite fabrication was achieved between visible -light absorbing anthrylene-and ferrocenoyl-substituted acetylenic dyes and single-wall carbon nanotubes (SWCNTs). The composite formation was con-firmed via UV-Vis, Raman, mass, and XPS spectra analyses. In the UV-Vis absorption spectrum, the resulting dye-SWCNT composites showed bathochromic shifts ascribable to the pi-pi interaction. One-pot fabrication of the composite was also accomplished via Cu-catalyzed dimerization of anthrylene-and ferrocenoyl-substituted terminal ethyne and the subsequent adsorption of the resulting butadiyne dye to SWCNT. We con-firmed that the dye-SWCNT composite dispersed in water by using amphiphilic poly(amidoamine)dendrimer could transfer an electron from 1-benzyl-1,4-dihydronicotinamide (BNAH) to methyl viologen dichloride (MV2+) upon irradiation with visi-ble light (>422 nm).

The present study reports a surprising protein-condensing effect of glucose, prompted by our accidental observation during chemical library screening under a high-glucose condition. We noticed "glucosing-out" of certain compounds, in which physiological concentrations of glucose induced compound aggregation. Adapting the "glucosing-out" concept to proteins, our proteomic analysis identified three cellular proteins (calmodulin, rho guanine nucleotide exchange factor 40, and polyubiquitin-C) that displayed robust glucose-dependent precipitation. One of these proteins, calmodulin, formed glucose-dependent condensates that control cellular glycogenolysis in hepatic cells. Our findings suggest that glucose is a heretofore underappreciated driver of protein phase separation that may have profound effects on cellular homeostasis.