SPring-8 Synchrotron Radiation Research Articles

Large Lithium Storage of Hydrothermally Synthesized TiNb2O7 Particles

Introduction Lithium-ion batteries using Li4Ti5O12 anode realize excellent performance of power, fast-charge, life, and safety [1]. However, the theoretical capacity of LTO is low (175 mAh/g) compared to that of graphite anode. We have been developing TiNb2O7 (TNO) as high-capacity anode material in order to replace the LTO anode [2]. The theoretical capacity of TNO is 387.6 mAh/g according to 5 Li insertion per formula unit, regarding electron transfer about Nb5+/Nb3+, Ti4+/Ti3+redox couples. Only a few researchers have reported on a large storage of more than 4 Li insertion (310 mAh/g). Hence, we report the lithium storage mechanism and electrode performance of hydrothermally synthesized TNO particles with the large storage of more than 4 Li insertion. Experimental TNO particle samples were synthesized by hydrothermal method. Niobium (V) chloride was dissolved in ethanol, and become mixed with Titanium (IV) oxysulfate dissolved in dilute sulfuric acid. Ammonia solution was slowly dropped to mixed solution with stirring until pH values were changed to 8. The mixture was transferred to autoclave, and gave a thermal treatment for 5 hours at 160℃. After that, the mixture was washed with deionized water and was frozen and dried in vacuum. The precursor samples were heated from 700℃ to 1000℃ for 30min, and furnace cooled. To compare with electrode performance of TNO, we also prepared TNO particle sample by solid state reaction using conventional method. Electrochemical properties were carried out using a three-electrode cell with synthesized TNO anodes as working electrodes, and Li foils as reference and counter electrodes. The structural changes of TNO particles as lithium insertion proceeded were characterized using ex-situ XRD, and XAFS measurements at the BL16B2 beam line in the SPring-8 synchrotron radiation research facility. Results and discussion Fig.1 shows charge (Li insertion) - discharge (Li extraction) curves of TNO electrodes at the first cycle. The TNO particles prepared by solid state reaction had a reversible capacity of 306 mAh/g, which was correspond to 3.95 of Li insertion amount per formula unit. On the other hand, hydrothermally synthesized TNO particles heated at 1000℃ had a large reversible capacity of 341 mAh/g (4.40 of Li/ formula unit) by the increase in capacity below 1.0 V (vs.Li+/Li). The reversible capacity per volume calculated using the true density of TNO was 1481 mAh/cm3, which is twice higher than that of graphite anode. Fig.2 shows the dQ/dV-V plots at the first discharge curves. The hydrothermally synthesized TNO anode had an additional peak around 1.0 V (vs. Li+/Li), which was significantly different from solid state reaction particles. Primary particle size (ca.100 nm) of hydrothermally synthesized TNO was much smaller than that (ca. 1 μm) of TNO synthesized by solid state reaction as shown in Fig.3. We consider that a short diffusion length of lithium ions, a large surface area, and highly crystallization of thermally synthesized TNO particle would make it possible to insert into a storage site of lithium ions above 4.0 per formula unit. We will give a description about the Li insertion and extraction mechanism of TNO at below 1.0 V (vs. Li+/Li) by using electrochemical analysis, ex-situ XRD, and XAFS measurements.

Transition from melting to carbonization of naphthalene, anthracene, pyrene and coronene at high pressure

We have examined the decomposition of naphthalene, anthracene, pyrene and coronene at high pressures and temperatures. Experiments were performed using in situ X-ray diffraction in multianvil apparatus at the SPring-8 synchrotron radiation facility. In the pressure range of 1.5–3.7GPa decomposition of studied polycyclic aromatic hydrocarbons (PAHs) was detected at 773–973K. Melting was identified only for naphthalene at 727–730K and 1.5GPa. Quenched products analyzed by Raman spectroscopy consist of nano- and microcrystalline graphite. The triple points between solid, liquid and carbonized (decomposed) PAHs were placed at 1–2GPa and 800–850K. Analyses of P-V-T data indicate that anthracene and coronene possess very low thermal expansion at 1.3–4.2GPa. The obtained melting and decomposition parameters for PAH restrict PT-conditions of their formation by local impacts during early planetary history, as well as provide evidences for secondary origin of PAH inclusions in natural mantle minerals from kimberlites.

Crystallization and preliminary X-ray diffraction analysis of recombinant phosphoribosylpyrophosphate synthetase from the Thermophilic thermus thermophilus strain HB27

Phosphoribosylpyrophosphate synthetases (PRPP synthetases) are among the key enzymes essential for vital functions of organisms and are involved in the biosynthesis of purine and pyrimidine nucleotides, coenzymes, and the amino acids histidine and tryptophan. These enzymes are used in biotechnology for the combined chemoenzymatic synthesis of natural nucleotide analogs. Recombinant phosphoribosylpyrophosphate synthetase I from the thermophilic strain HB27 of the bacterium Thermus thermophilus (T. th HB27) has high thermal stability and shows maximum activity at 75°С, due to which this enzyme holds promise for biotechnological applications. In order to grow crystals and study them by X-ray crystallography, an enzyme sample, which was produced using a highly efficient producer strain, was purified by affinity and gel-filtration chromatography. The screening of crystallization conditions was performed by the vapor-diffusion technique. The crystals of the enzyme suitable for X-ray diffraction were grown by the counter-diffusion method through a gel layer. These crystals were used to collect the X-ray diffraction data set at the SPring-8 synchrotron radiation facility (Japan) to 3-A resolution. The crystals belong to sp. gr. P21 and have the following unitcell parameters: a = 107.7 A, b = 112.6 A, c = 110.2 A, α = γ = 90°, β = 116.6°. The X-ray diffraction data set is suitable for determining the three-dimensional structure of the enzyme at 3.0-A resolution.

Intact Imaging of Human Heart Structure Using X-ray Phase-Contrast Tomography

Structural examination of human heart specimens at the microscopic level is a prerequisite for understanding congenital heart diseases. It is desirable not to destroy or alter the properties of such specimens because of their scarcity. However, many of the currently available imaging techniques either destroy the specimen through sectioning or alter the chemical and mechanical properties of the specimen through staining and contrast agent injection. As a result, subsequent studies may not be possible. X-ray phase-contrast tomography is an imaging modality for biological soft tissues that does not destroy or alter the properties of the specimen. The feasibility of X-ray phase-contrast tomography for the structural examination of heart specimens was tested using infantile and fetal heart specimens without congenital diseases. X-ray phase-contrast tomography was carried out at the SPring-8 synchrotron radiation facility using the Talbot grating interferometer at the bending magnet beamline BL20B2 to visualize the structure of five non-pretreated whole heart specimens obtained by autopsy. High-resolution, three-dimensional images were obtained for all specimens. The images clearly showed the myocardial structure, coronary vessels, and conduction bundle. X-ray phase-contrast tomography allows high-resolution, three-dimensional imaging of human heart specimens. Intact imaging using X-ray phase-contrast tomography can contribute to further structural investigation of heart specimens with congenital heart diseases.

Three Dimensional Visualization of Human Cardiac Conduction Tissue in Whole Heart Specimens by High-Resolution Phase-Contrast CT Imaging Using Synchrotron Radiation.

The feasibility of synchrotron radiation-based phase-contrast computed tomography (PCCT) for visualization of the atrioventricular (AV) conduction axis in human whole heart specimens was tested using four postmortem structurally normal newborn hearts obtained at autopsy. A PCCT imaging system at the beamline BL20B2 in a SPring-8 synchrotron radiation facility was used. The PCCT imaging of the conduction system was performed with "virtual" slicing of the three-dimensional reconstructed images. For histological verification, specimens were cut into planes similar to the PCCT images, then cut into 5-μm serial sections and stained with Masson's trichrome. In PCCT images of all four of the whole hearts of newborns, the AV conduction axis was distinguished as a low-density structure, which was serially traceable from the compact node to the penetrating bundle within the central fibrous body, and to the branching bundle into the left and right bundle branches. This was verified by histological serial sectioning. This is the first demonstration that visualization of the AV conduction axis within human whole heart specimens is feasible with PCCT.

Crystallization and preliminary X-ray diffraction study of recombinant ribokinase from Thermus Species 2.9

Ribokinase from a thermophilic strain of Thermus species 2.9 belonging to the carbohydrate ribokinase family (EC 2.7.1.15) was isolated, purified, and crystallized. The crystallization conditions were found by the vapor-diffusion technique and were then optimized to apply the capillary counter-diffusion technique. The X-ray diffraction data set was collected from the crystals, which were grown by the counter-diffusion technique, at the SPring-8 synchrotron radiation facility to 2.87 A resolution. The crystals belong to sp. gr. P1211 and have the following unit-cell parameters: a = 81.613 A, b = 156.132 A, c = 87.714 A, α = γ = 90°, β = 103.819°. The X-ray diffraction data set is suitable for determining the three-dimensional structure of the protein by the molecular-replacement method.

Studies of print-through and reflectivity of x-ray mirrors using thin carbon-fiber-reinforced plastic

We fabricated x-ray mirrors from carbon-fiber-reinforced plastic with a tightly nested design for x-ray satellites, using a replication method for the surfaces. We studied the effects of print-through on the mirror surface as a function of curing temperature. With room temperature curing, the root-mean-square value of the surface error was 0.8 nm. The reflectivity was measured using 8-keV x-rays, and the roughness was calculated as 0.5 nm by model fitting—comparable to that of the ASTRO-H/HXT mirror. We verified the long-term stability of the mirror surface over 6 months. We fabricated Wolter type-I quadrant-shell mirrors with a diameter of 200 mm and performed x-ray measurements at BL20B2 in the SPring-8 synchrotron radiation facility. We obtained reflection images of the mirrors using a 20-keV x-ray spot beam with a slit size of 10×1 mm in the radial and circumferential directions, respectively. The averaged half-power diameter (HPD) of the images in one mirror was 1.2 arc min in the circumferential center of the mirror and 3.0 arc min at the edge. In the spot images with a smaller slit size of 10×0.2 mm, we achieved an HPD of 0.38 arc min in the best case.

SPring-8 synchrotron radiation imaging for analyzing cardiovascular function in anesthetized small animals.

近年の分子生物学の発展により，種々の細胞の特性が遺伝子・タンパク質レベルで次々に明らかにされてきた．他方，このような要素的知識を統合して生体を有機的にとらえる研究が益々重要となっている．マウスなどの小動物は，遺伝子導入や欠損などの遺伝子操作技術が確立し，また，短期間での病態モデル作成が容易であることから，要素的知識を個体レベルに還元して検証する研究において重要な位置をしめている．本稿では，著者らが進めてきたSPring-8高輝度放射光X線による麻酔下小動物での心血管運動機能の解析法を紹介する．一つは，透過X線による高解像度微小血管造影法である．固定臓器の微小血管（内径～30 μm）はもちろん，高心拍数のマウス心臓の冠細動脈（内径～50 μm）の応答も臓器を露出することなく撮影可能である．本法のメリットは，臓器表層から内層にわたる，あるがままの血管ネットワーク上において，大血管と小血管の応答の差異を同一画面で同時に評価できることである．また，臓器内の血流分布や循環時間の情報も得ることができる．遺伝子改変マウスへの応用によって，循環調節や病態の分子機序の解明が進むものと期待されている．二つ目は，散乱X線を利用した心筋X線回折法である．ナノレベルの心筋収縮タンパク質分子のcrossbridge動態を心室壁の任意の心筋部位においてピンポイント（0.2×0.2 mm）で評価でき，心筋機能異常の詳細な分布の把握を可能とする．また，iPS細胞などによる再生心筋の局所的機能評価にも応用できる．

C3-P-033-D cell geometrical analysis of epidermal and cortical cells in hypocotyl-root axes in arabidopsis seeds using X-ray micro-CT

Plants are composed of various types of cells. How these cells contribute to the overall body shape of plants is an important question in studies of plant development. Because plant cells are surrounded by rigid cell walls, newly formed cells are unable to migrate, and the geometrical relationships among neighboring cells are maintained for a long time during plant development. In arabidopsis (Arabidopsis thaliana (L.) Heynh. ecotype Columbia) seeds, one cortical cell layer exists between the epidermis and endodermis in the radicle, and two cortical cell layers are present in the hypocotyl. However, how the shape and geometry of these cells in the epidermis and cortex contribute to the embryo form remains unknown. We previously determined the three-dimensional (3-D) cell and tissue shapes and geometries in the embryo of an arabidopsis dry seed with X-ray micro computed tomography (micro-CT) using beamline BL20XU of SPring-8 synchrotron radiation facility [1]. In the present study, we constructed 3-D models of cell arrangement based on X-ray micro-CT images (8 keV, 0.2 μm/pixel) of whole seeds of arabidopsis, and analyzed the geometrical characteristics of epidermal and cortical cells. The size of the cross-sectional area of hypocotyl–root axis is largest in the proximal region of the hypocotyl, ~80 μm from the hypocotyl–root transition zone. Comparison between the cell division pattern and the change in cell size along the hypocotyl–root axis revealed that the increment in the lateral expansion of cortical cells contributed to the lateral expansion of the hypocotyl axis. In contrast, only the number of cell files, and not the size of cross-sectional area, increased when the area of epidermis increased. This work was partly supported by a grant from Hyogo Science and Technology Association. Experiments were performed with the approval of JASRI (Proposal nos 2012A1364 and 2014A1265). [1] D Yamauchi et al., AIP Conf. Proc. 1466 (2012) 237-242. C3-P-02 doi:10.1093/jmicro/dfv305

In situ X-ray diffraction study of decomposition of polycyclic aromatic hydrocarbons at pressures of 7–15 GPa: Implication to fluids under the Earth's and planetary environments

The behavior of polycyclic aromatic hydrocarbons (PAHs) at high pressures and temperatures has been investigated as a part of study of the deep-seated C–O–H fluids in the Earth and planetary interiors. The theoretical calculations of fluid compositions at the Earth's mantle conditions in the simple C–O–H system indicate that dominant fluid species are CH4 and H2O, with subordinate H2, and heavier hydrocarbons. However, calculations of equations of state for a broader range of hydrocarbons predict an appearance of heavy alkanes and PAHs under high pressures (>6–7GPa). Here, we determined stability of the major PAHs (from naphthalene to coronene) using in situ X-ray diffraction in multianvil apparatus at the SPring-8 synchrotron radiation facility (Japan). It was found, that at 7–9GPa, PAHs become unstable at temperatures above 873–1073K. We suggest that stability of PAHs is limited by benzene ring decomposition. The data for coronene only at 15GPa confirms limited temperature stability of PAHs. The PAH decomposition products consist of amorphous hydrogenated carbon at 7–9GPa at 973–1073K. Coronene decomposition products consist of diamond and trans-polyacetylene at 15.5GPa and 973K. Determined PAH decomposition temperatures (873–1073K) are lower than known Earth's geotherms and subduction slab P–T profiles at pressures of 7–9GPa (220–280km depths). According to these data, PAH inclusions in mantle garnet and diamond should be of secondary origin, precipitating from mantle-derived fluids after or prior to kimberlite magma eruption. Limited temperature stability of PAHs restricts the parameters of their formation in meteorite by high-temperature impact events during early Solar System history.

3D image analysis of plants using electron tomography and micro-CT.

Precise control of the cell division plane is a prerequisite for plant development. The division site (the position of the division plane insertion) in plant cells is the site along which the cell plate margin joins the parental cell walls. How this division site is determined and established during cell division is an essential question in plant morphogenesis. Herein we demonstrate how computer tomography techniques can aid in understanding nano-machines involved in determination of the division site and in analysing air space development after cytokinesis. The preprophase band (PPB) is a cytokinetic nano-machine used to determine the plant division site. The PPB appears as a broad microtubule (MT) band in the G2 phase and the MT band narrows during the prophase to establish the specialized belt zone in the cell cortex (cortical division zone, [CDZ]). The MT band disappears at prometaphase, but some memories remain in the CDZ throughout the process of cell division, and this is the site of attachment of the newly formed cell plate. We have examined PPB development of high-pressure frozen onion cotyledon epidermis using dual-axis electron tomography. MTs as well as actin microfilaments (MFs) and membrane systems can be preserved well by high-pressure freezing [1]. Since detection of ∼100 vesicles and ∼40 MT ends was possible in a tomogram of the PPB surface (0.25 mm × 0.25 mm) obtained from 250-nm-thick tangential sections of epidermal cells, we were able to quantitatively analyze the frequencies of various types of vesicles and MT ends in the PPB [2]. The results clearly showed that endocytosis is active [2,3] and MTs are very dynamic in the late PPB. Light microscopic studies with fluorescent probes have demonstrated that actins are among the main components of PPB. Electron tomography analysis showed that one actin configuration in the PPB is a relatively short single MFs running parallel to the plasma membrane. The actin MFs connecting two adjacent MTs help to promote MT bundling. Cell plate attachment to the parental wall leads to the fusion of the newly formed middle lamellae in the cell plate to the middle lamella of parental cell wall, and a three-way junction is created. Air space develops from the three-way junction. To determine 3D arrangement of cells and air spaces, we used X-ray micro-CT at the SPring-8 synchrotron radiation facility. Using micro-CT available in BL20XU (8 keV, 0.2 µm/pixel), we were able to elucidate ∼90% of the cortical cell outlines in the hypocotyl-radicle axis of arabidopsis seeds [4] and to analyze cell geometrical properties. As the strength of the system X-ray is too strong for seed survival, we used another beam line BL20B2 (10-15 keV, 2.4-2.7 µm/pixel) to examine air space development during seed imbibition [4,5]. Using this system, we were able to detect air space development at the early imbibition stages of seeds without causing damage during seed germination. AcknowledgmentThe author would like to thank Dr. Ichirou Karahara (Univ. Toyama), Dr. L. Andrew Staehelin (Univ. Colorado), Ms. Naoko Kajimura, Dr. Akio Takaoka (Osaka Univ.), Dr. Kazuyo Misaki, Dr. Shigenobu Yonemura (RIKEN CDB), Dr. Kazuyoshi Murata (NIP), Dr. Kentaro Uesugi, Dr. Akihisa Takeuchi, Dr. Yoshio Suzuki (JASRI), Dr. Miyuki Takeuchi, Dr. Daisuke Tamaoki, Dr. Daisuke Yamauchi, and Ms. Aki Fukuda (Univ. Hyogo) for their collaborations in the work presented here.

Enhanced oxygen barrier property of poly(ethylene oxide) films crystallite-oriented by adding cellulose single nanofibers

In this study, we investigated the influence of cellulose single nanofibers (CSNFs) added to poly(ethylene oxide) (PEO) on the microstructure and property to create high gas barrier films. The CSNF/PEO nanocomposite films were prepared by solvent casting. The PEO crystallite orientation was measured using wide-angle X-ray diffraction of the SPring-8 synchrotron radiation facility. The degree of crystallite orientation was evaluated from the reflections of the PEO (1 2 0) lattice planes to investigate quantitatively the effect of different amounts of the additive CSNFs. The crystallite orientation of PEO increased with the addition of the CSNF. Furthermore, the oxygen barrier property for each nanocomposite film was found to be higher than that of the pure PEO film. The 5 wt% addition of CSNFs was mostly effective in enhancing the PEO crystallite orientation and oxygen barrier.

Clarifying the mechanism of aggregation of particles in high-shear granulation based on their surface properties by using micro-spectroscopy

The present study aimed to clarify, by means of micro-spectroscopy, the mechanism of aggregation of particles into granules during high-shear granulation. We used two types of pharmaceutical granules prepared by high-shear granulator, one containing mefenamic acid and the other containing flavoxate hydrochloride as poorly soluble active pharmaceutical ingredients (APIs). Lactose, cornstarch, and microcrystalline cellulose were used as excipients; and hydroxypropyl cellulose (HPC) was used as the binding agent. The distributions of components in granules were visualized by mapping cross-sections of individual granules with techniques utilizing mid-infrared spectroscopy at the SPring-8 synchrotron radiation facility and micro-Raman spectroscopy. In the distribution maps of mefenamic acid granules, distributions of mefenamic acid, cornstarch, and microcrystalline cellulose overlapped; in flavoxate hydrochloride granules, on the other hand, distributions of flavoxate hydrochloride and lactose overlapped. Assessment of the surface free energy of each component found that ingredients with overlapping distribution had similar surface properties. Therefore, it was revealed that in high-shear granulation, in addition to the granulator operating conditions and general properties of the formulation itself (such as the solubility and particle size of each ingredient), the surface properties of the ingredients and their interrelationships were also factors that determined the aggregation behavior of the particles.

Microstructures of BPDA-PPD polyimide thin films with different thicknesses

The microstructures of 3,4,3′,4′-biphenyltetracarboxylic dianhydride –p-phenylene diamine (BPDA-PPD) polyimide (PI) thin films with different thicknesses were investigated by grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XRR) at the SPring-8 synchrotron radiation facility. The film density calculated from XRR profiles increased with decreasing the film thickness. Processing of PI thin films from precursor polyamic acid (PAA) solutions involves simultaneous thermal imidization, evaporation of residual solvents and crystallization. The thickness reduction during imidization was smaller for the thinner PAA film. This implies that the much more larger amount of the residual solvent in the thinner PAA film brings high molecular mobility, which results in the higher conversion to PI at any curing temperature. The thinner BPDA-PPD film was more dense than the thicker film because of better molecular packing, which is a result of much more amount of the residual solvent for the thinner film during the thermal curing.

Determination of the structure of liquids containing free radical molecules: Inter-molecular correlations in liquid chlorine dioxide

X-ray diffraction spectra of liquid ClO2 at 204, 223, 248 and 273 K were measured at the BL04B2 beamline in the SPring-8 synchrotron radiation facility. The obtained structure factors are well reproduced by reverse Monte Carlo (RMC) structural modelling. With increasing temperature, the first peak located at around Q = 1.8 Å −1 slightly shifts to higher Q and the tail at the lower-Q side intensifies. In the pair distribution function, g(r), the intensity of the peak at around 3.2 Å that corresponds to the nearest-neighbour distance decreases with increasing temperature. The analysis of the RMC configurations shows that strong directional O–O interaction exists in liquid ClO2 and the instantaneous inter-molecular orientation depends on this interaction.

Monitoring system for a synthesizer at SPring-8 synchrotron radiation facility and obtained results

Beam orbit distortion in all dispersive sections was observed in the SPring-8 storage ring during beam commissioning. In order to confirm the stability of the radio frequency (RF) synthesizer, a monitoring system was developed. The system consists of a frequency counter referenced to a global positioning system (GPS) receiver. With this system, the output of the synthesizer, which uses an external 10MHz-Rubidium atomic clock with the time accuracy of Δt/t=10−12, is correctly monitored with 11 digits absolute accuracy, verifying that the synthesizer works well. Measurement of the circumference of the SPring-8 storage ring reveals the effect of tidal forces and seasonal temperature variations on beam orbit. To maintain the center axis of photon radiation in experimental beam lines, a beam energy correction is carried out. The frequency of the RF synthesizer is changed every 5min with 10-digit accuracy. This corresponds to an energy accuracy of ΔE/E=1.16×10−6. The monitoring system for the synthesizer and obtained results are described.

Phase-contrast X-ray microtomography of mouse fetus

SummaryA phase-contrast X-ray microtomography system using the Talbot imaging has been built at the SPring-8 synchrotron radiation facility. This system has much higher density resolution than absorption-based X-ray microtomography. The tomographic sections of formalin-fixed mouse fetuses obtained with this method clearly depict various organs without any staining at a pixel resolution of up to 5 µm. Since this technique allows us to obtain three-dimensional structural information without sectioning, it will be particularly useful to examine anomalies that take place during development. It can be also used to quantitatively measure volume and mass of organs during development.

Densification of chemical vapor deposition silicon dioxide film using oxygen radical oxidation

Silicon dioxide (SiO2) films formed by chemical vapor deposition (CVD) were treated with oxygen radical oxidation using Ar/O2 plasma excited by microwave. The mass density depth profiles, carrier trap densities, and current-voltage characteristics of the radical-oxidized CVD-SiO2 films were investigated. The mass density depth profiles were estimated with x ray reflectivity measurement using synchrotron radiation of SPring-8. The carrier trap densities were estimated with x ray photoelectron spectroscopy time-dependent measurement. The mass densities of the radical-oxidized CVD-SiO2 films were increased near the SiO2 surface. The densities of the carrier trap centers in these films were decreased. The leakage currents of the metal-oxide-semiconductor capacitors fabricated by using these films were reduced. It is probable that the insulation properties of the CVD-SiO2 film are improved by the increase in the mass density and the decrease in the carrier trap density caused by the restoration of the Si-O network with the radical oxidation.

Atomic and electronic structure of Pd40Ni40P20bulk metallic glass fromab initiosimulations

The atomic structure of Pd${}_{40}$Ni${}_{40}$P${}_{20}$ bulk metallic glass has been simulated using an ab initio molecular dynamics method with projector-augmented wave pseudopotentials for electron-ion interaction and generalized gradient approximation for exchange-correlation energy. The calculated extended x-ray absorption fine structure (EXAFS) spectra of Pd-K and Ni-K edges, the mass density, and the electronic structure agree remarkably well with the available experimental data and the EXAFS spectra measured at the SPring-8 synchrotron radiation facility. Our results show that the atomic structure can be described in terms of P-centered polyhedra. There are no two P atoms that are nearest neighbors at this composition, and this could be a reason for the observed optimal P concentration of about 20 at.%. The neighboring polyhedra share metal (M) atoms and form a polar covalently bonded random network of P-M-P favoring certain angles. The remaining M atoms act as metallic glue with a tendency of nanoscale clustering of Pd-Pd and Ni-Ni atoms.

Drug Delivery Observation of Hydrophobe Ferrofluid and Magnetite Nanoparticals by SPring-8 Synchrotron Radiation

In this study, the composite magnetic nanoparticles of coated SiO nano film with about 8 nm size and high saturation magnetization value, were synthesized by liquid phase precipitation method. The magnetic nanoparticles can be dispersed in various liquid media, widely known as magnetic fluids or ferrofluids with both magnetic and liquid properties. The materials been collected great interests and more and more attentions to focus into Drug Delivery System (DDS) as a new technology in this paper. We use the composite nanoparticles to disperse H2O and inject the solutions into rat's in-vivo organs. And, in the experiments by using a strong photon beam of SPring-8 Synchrotron Radiation facility, the distribution stat and the effects of magnetic field as well as drug delivery behaviour of nanoparticles in the rat' kidney are verified by the in-vivo observations.