Diffraction Intensity Ratio Research Articles

1113 EARLY DIABETIC DIASTOLIC DYSFUNCTION DISPLACES MYOSIN HEADS FROM ACTIN IN THE BEATING HEART

Background: Left ventricular (LV) diastolic dysfunction is the earliest diagnostic indicator of diabetic cardiomyopathy in the clinic. Impaired relaxation is frequently attributed to LV fibrosis. Our aim was to investigate in vivo cross-bridge dynamics in diabetic hearts prior to the onset of fibrosis. Methods: Our small angle X-ray scattering approach was used to investigate cross-bridge dynamics and myosin head proximity to actin in the open-chest beating rat heart 3 weeks after inducing diabetes with streptozotocin simultaneous with LV pressure-volume recordings. The ratio of the intensity of myosin only reflections to myosin-actin reflections was used to determine myosin head proximity to actin (mass transfer), cross-bridge attachments and interfilament spacing during baseline conditions and dobutamine stimulation to increase contractility. Results: We found that diastolic diffraction intensity ratio was significantly elevated by diabetes, relative to control rat hearts (<3.5), and increased with depth within the LV wall (3.5–6.0). Elevated diastolic intensity ratio was strongly correlated with suppression of LV dP/dt minimum. Increased diastolic separation of myosin-actin filaments in diabetic hearts was reduced by dobutamine, but the increase in systolic cross-bridge attachments was reduced relative to controls (sub-epicardium 61 to 64% diabetic v. 77 to 95% control). Interfilament spacing and likely sarcomere length did not differ between groups. Conclusions: In the setting of type-I diabetes myosin heads were found to be displaced from actin filaments in the fibres of beating heart muscle. Increased diastolic separation of actin-myosin filaments was not related to estimated sarcomere length, but directly related to impaired relaxation of the LV.

Direct Observation of Charge Ordering in Magnetite Using Resonant Multiwave X-Ray Diffraction

Charge disproportion at octahedral Fe sites in magnetite was observed at low temperature using two inversion-symmetry related three-wave resonant x-ray diffraction, 022-311 and 002-̅3̅1, near the iron K edge. Both of the three-wave cases involve the (002) forbidden-weak reflection. The self-normalized three-wave to two-wave (002) diffraction intensity ratio automatically cancels the self-absorption effect and leads to direct determination of charge disproportion for magnetite below 120 K. This approach provides a more direct and effective way for extracting charge-ordering information.

Analysis of Biological Apatite Crystal Orientation in Anterior Cortical Bone of Human Mandible Using Microbeam X-ray Diffractometry

The human jaw is a unique bone that facilitates mastication. The structural properties of the jaw are determined by mechanical stresses transmitted via the teeth. However, it is very difficult to evaluate the impact of these mechanical stresses on bone. In recent years, it has become clear that the orientation of biological apatite (BAp) crystals is closely related to local stress, and is thought to respond more acutely to local stress than bone mineral density (BMD). Few studies have been conducted on BAp crystal alignment in response to mechanical stress in the human jaw, which has a complex masticatory function. The purpose of this study was to quantitatively evaluate BMD and BAp crystal orientation using micro-computed tomography (micro-CT) and microbeam X-ray diffractometry in the anterior cortical bone of human mandible. The intensity and direction of mechanical stresses in both the alveolar area and mandibular base were compared. The mandibular central incisor region in Japanese bone samples was designated as the region of interest and BMD and BAp crystal orientation in the alveolar area and mandibular base measured. Bone samples were imaged by micro-CT and the data obtained converted into BMD values. BAp crystal orientation was determined by both reflection- and transmission-based microbeam X-ray diffractometry. The diffraction intensity ratio was calculated using X-ray diffraction peaks of (002) and (310). The results showed no difference in BMD values among regions. BAp crystals were oriented predominantly in the mesiodistal direction in the mandibular base and along the direction of masticatory force in the alveolar area. These findings suggest that the mandibular base exhibits long bone-like characteristics, with the mandibular condyle acting as the head of the bone, while in the alveolar area alignment takes place in the direction of masticatory force resulting from mechanical stress exerted via the teeth. Qualitative evaluation revealed clear differences between the mandibular base and alveolar area, suggesting that BAp crystal orientation offers a more precise indicator of bone quality than BMD. [doi:10.2320/matertrans.M2011329]

Microstructure and Crystalline Texture Quality of $L1_{0}$ Ordered Fe-Pt-Ag-C Alloy Recording Media

Fe-Pt-Ag-SiO2 and Fe-Pt-Ag-C granular recording media with an L10 ordered structure were fabricated using an in-line sputtering system with full-surface alloy targets. To understand the degree of ordering, the x-ray diffraction intensity ratio of a superlattice peak to a fundamental peak was measured for various samples. Some samples showed large intensity ratios despite having low anisotropy energy. This can be explained by the simple theory that the relative intensity at a low diffraction angle increases for samples with weaker preferred orientation. That is, the intensity ratio is affected not only by the degree of ordering but also by the crystalline texture quality. The larger intensity ratio of Fe-Pt-Ag-C media than that of Fe-Pt-Ag-SiO2 media was interpreted as the degraded Fe-Pt(001) texture of Fe-Pt-Ag-C media. Thus, good Fe-Pt(001) texture needs to be achieved without deteriorating the well-isolated granular structure in Fe-Pt-Ag-C media.

Ag가 첨가된 0.9(Na0.52K0.48)NbO3-0.1LiTaO3세라믹스

Lead-free <TEX>$0.9(Na_{0.52}K_{0.48})NbO_3$</TEX> - <TEX>$0.1LiTaO_3$</TEX> piezoelectric ceramics doped with <TEX>$Ag_2O$</TEX> (0-4 mol%) have been prepared by the conventional mixed oxide method. The structural and electrical properties were analyzed in order to find its potential applications. The crystal structure of 1-4 mol% Ag doped <TEX>$0.9(Na_{0.52}K_{0.48})NbO_3$</TEX>-<TEX>$0.1LiTaO_3$</TEX> lead free piezoelectric ceramics were investigated for several sintering temperatures (<TEX>$1100^{\circ}C$</TEX>) by the use of X-ray diffraction analysis. In order to analyze the effect of Ag dopants on the <TEX>$0.9(Na_{0.52}K_{0.48})NbO_3$</TEX>-<TEX>$0.1LiTaO_3$</TEX> ceramic, the diffraction intensity ratio of the (002) to (200) planes were calculated from the X-ray diffraction patterns of the ceramic samples.

XRD studies on the electrode materials in the charge-discharge process of a graphite/Li（Ni1/3Co1/3Mn1/3）O2 battery

Structure transformation and microstructure of the electrode active materials in a graphite / Li （Ni1/3Co1/3Mn1/3）O2 lithium ion battery during charge-discharge process have been studied by XRD. It is found that the lattice parameter of Li （Ni1/3Co1/3Mn1/3）O2, a and c, decrease and increase respectively. Its micro-strain ε and diffraction intensity ratio, I104/I101 and I012/I101, increases and decrease respectively, because Li atoms de-intercalate out of the crystal lattice of LiMO2. Meanwhile, the lattice parameter, a and c, micro-strain ε and stacking disorder P of 2H-graphite all increase, becausing Li atoms to intercalate into 2H-graphite.During charge process, Li atoms occupying （000） sites may preferentially de-intercalate from LiMO2 crystal lattice, and subsequently the Li atoms occupying （2/3 1/3 1/3）and（1/3 2/3 2/3）sites de-intercalate from LiMO2. When intercalating into 2H-graphite, Li atoms preferentially occupy interstitial sites between C atom hexagonal net planes. When the stacking disorder degree reaches a given value, 3R-graphite phase may separate out gradually. When the battery has been fully charged or over charged, LiC12 and LiC6 phases can be formed. During discharge process, intercalation and de-intercalation behaviors of Li atoms are reversed. Li atoms may de-intercalate preferentially from interstitial sites of 2H-graphite and intercalate preferentially into （000） sites of LiMO2 crystal lattice. But these processes are not fully reversible.

Determination of A-site deficiency in lanthanum manganite by XRD intensity ratio

A method based on the X-ray diffraction intensity ratio was developed to determine the maximum deficiency that the perovskite-structured La 1− x MnO 3± δ can accommodate at the A-site. Computer simulation predicts that the intensity ratio of (024) and (012) reflections for La 1− x MnO 3± δ in hexagonal setting increases with increasing the La deficiency x. XRD analysis shows that with increasing x until 0.09, the ratio increases as predicted, then levels off with further increase in x. An abrupt change in electrical conductivity is also observed at x of ∼0.10. It is concluded that the maximum deficiency lies in between 0.09 and 0.10 for La 1− x MnO 3± δ . The methodology presented in this paper in principle can be applied to other perovskite-structured materials.

AN INVESTIGATION OF SMOOTH NANOSIZED COPPER FILMS ON GLASS SUBSTRATE BY IMPROVED ELECTROLESS PLATING

Thin nanocrystalline Cu films (&lt; 1 μm) are deposited on a glass substrate using an improved electroless plating technique. The deposition course of the Cu film is illustrated by the variation of surface morphology with different deposition time. The results show that a more uniform and continuous nanocrystalline Cu film with very small nodules can be formed on a glass substrate at the deposition time over 1 min. The roles of SDBS as an additive in the bath are also discussed. According to the relation of the film thickness and the deposition time, it is obvious that the film thickness nearly linearly varies with the deposition time in the present work. An enhanced (111) texture with the diffraction intensity ratio (I(111)/I(200)) of about 4.0 and the very fine grain size of 15–28 nm determined by X-ray results has been observed. The variations of the resistivity show that it is strongly affected by the film thickness and grain size.

Fabrication of La 0.85Na 0.15Mn 1−xNi xO 3 ( [formula omitted], 0.05, 0.1) thin films on Si substrates via chemical solution deposition

Polycrystalline La 0.85Na 0.15Mn 1− x Ni x O 3 ( x = 0 , 0.05, 0.1) thin films were successfully fabricated on Si (1 0 0) substrates using chemical solution deposition method. The results revealed that with the increase of the Ni content, the X-ray diffraction intensity ratio of I (1 1 1) / I (2 0 0) increased, whereas both the grain size and the roughness decreased. The magnetic and transport measurements showed that it was effective to tune the magnetoresistance (MR) effects via Ni doping at Mn sites.

Determination of crystallographic polarity of ZnO bulk crystals and epilayers

AbstractThe crystallographic polarity of ZnO bulk crystals and epilayers were determined by X‐ray diffraction (XRD) using anomalous dispersion near the Zn K‐edge. The method is not destructive and is straightforward to carry out using a typical XRD measurement system. The polarity difference between the Zn (0001) and O (000$ \bar 1 $) surfaces could be easily determined using a {0002} diffraction peak and the Bremstrahlung radiation from a Cu rotating anode source. By using the normalized pre and post‐Zn K‐edge diffraction intensity ratios of the {0002} diffraction peak, Zn polar and O polar ZnO layers could always be distinguished but, the absolute value of the ratio was found to change with layer thickness. Acid etching results confirmed the veracity of the polarity determination of the XRD measurement. To test the technique, Zn and O polar ZnO layers were grown by radical source molecular beam epitaxy on MgO buffer layers on c‐sapphire substrate and O polar ZnO layers were grown on a‐plane substrates and measured using the X‐ray technique with excellent agreement. (© 2006 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Preparation and Properties of Transparent Glass-Ceramics in xK2O-(33.3-x)BaO-16.7TiO2-50SiO2 Glasses

Transparent surface crystallized glasses have been prepared by controlled heat treatment in the system xK2O-(33.3-x) BaO-16.7TiO2-50SiO2(0 ≤ x ≤ 20 mol%), and properties were investigated. The glassy nature was analyzed by differential thermal analyses. The transparency of glass-ceramics is variable and controllable by the processing parameters like time and temperature. The c-axis orientation of surface crystallized Ba2TiSi2O8 was observed at the bulk glass-ceramics surfaces and characterized the diffraction intensity ratio (002)/I(001). The estimated nonlinear optical susceptibility χ(3) is discussed in relation to the optical parameters.

Size effect on the ordering ofL10FePt nanoparticles

We have studied the size effect on the $\mathrm{L}{1}_{0}$ ordering of FePt (001) nanoparticles epitaxially grown on MgO (001). From the dark field images using 110 superlattice spots excited by incident electron beam along $[\overline{1}1l]$ $(l=4--6)$, the critical size for $\mathrm{L}{1}_{0}$ ordering has been evaluated to be $d=1.5--2\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ below which no ordering occurs. Further, we have taken an electron diffraction pattern of each FePt nanoparticle using a nanometer-sized electron beam and determined the respective long-range order parameter $S$ by analyzing the superlattice/fundamental diffraction intensity ratio based on the multislice method. It is found that the order parameter $S$ sharply drops below $d\ensuremath{\sim}3\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and decreases to zero for $dl2\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, the result is almost consistent with thermodynamic calculations previously reported. The present work unambiguously shows that the ordering of $\mathrm{L}{1}_{0}$ FePt is entirely inhibited when its size is less than $d\ensuremath{\sim}2\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Such size effect is not so serious for practical applications of FePt to permanent magnets or magnetic recording media because the effect is significant only for $dl2\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ where the $\mathrm{L}{1}_{0}$ FePt would be magnetically unstable due to severe thermal agitation.

Determination of crystallographic polarity of ZnO layers

The crystallographic polarity of ZnO epilayers was determined by x-ray diffraction (XRD) using anomalous dispersion near the Zn K edge. The method is not destructive and is straightforward to carry out using a typical XRD measurement system. The polarity difference between the Zn (0001) and O (0001¯) surfaces could be easily determined using a {0002} diffraction peak and the Bremstrahlung radiation from a Cu rotating anode source. By using the normalized pre- and post-Zn K-edge diffraction intensity ratios of the (0002) diffraction peak, Zn polar and O polar ZnO layers could always be distinguished but, the absolute value of the ratio was found to change with layer thickness. The absolute value of the ratio with layer thickness was found to have a linear dependence on layer thickness allowing determination of the polarity of (0001) ZnO epilayers with a single x-ray measurement and the known layer thickness in conjunction with standard data. Acid etching results confirmed the veracity of the polarity determination of the XRD measurement. To test the technique, Zn and O polar ZnO layers were grown by radical source molecular beam epitaxy (RS MBE) on MgO buffer layers on c-sapphire substrate and O polar ZnO layers were grown on a-plane substrates and measured using the x-ray technique with excellent agreement.

Analysis of a mixture containing ampicillin anhydrate and ampicillin trihydrate by thermogravimetry, oven heating, differential scanning calorimetry, and X-ray diffraction techniques

Because the solubility of ampicillin anhydrate is quite different from that of ampicillin trihydrate, four basic techniques were employed to rapidly and precisely quantify mixtures of ampicillin anhydrate and ampicillin trihydrate. Using thermogravimetry and oven heating in a porcelain crucible, their ratio in mixtures was precisely quantified according to weight loss of water from ampicillin trihydrate in the mixtures. The ratio was also quantified based on the enthalpy change of water in ampicillin trihydrate and the phase change of ampicillin itself as measured by a differential scanning calorimeter. The X-ray diffraction intensity ratio of the mixtures at two specific angles was shown to be proportional to the ratio of the mixtures. Accordingly, a linear relationship between a change of physicochemical properties and a selected ratio of the mixtures was established. Comparison of the sample used, the R 2 value from linear curve-fitting, the maximum error and maximum measure limit in different techniques is also presented.

A method to determine long-range order parameters from electron diffraction intensities detected by a CCD camera

To determine long-range order parameters from electron diffraction intensities, the authors have developed a CCD camera system to detect precisely electron diffraction intensities, a method for quickly and precisely measuring specimen thickness, and a computer programming to calculate long-range order parameters from the ratio of superlattice and fundamental diffraction intensities. Thickness variation over a diffraction area is taken into consideration in the calculation of electron diffraction intensities on the basis of the multi-slice method, and long-range order parameters are calculated by the successive approximation method. The absorptive form factors are also calculated from experimental data of diffraction intensities by parameter fitting, and the effect of absorption on the calculation of long-range order parameters is examined. The values of Cu 3Au alloys aged at 523 and 653 K that were obtained by averaging long-range order parameters determined for several diffraction areas with the developed method are close to the reported data obtained by the X-ray diffraction method. The main causes for the deviation of long-range order parameters determined for several diffraction areas are also discussed.

적층형 세라믹 액츄에이터의 세라믹-전극간 계면이 전기적 특성에 미치는 영향에 대한 연구

The polarization and strain behavior of multilayer ceramic actuators fabricated by tape casting using a PNN-PZT ceramics were investigated in association with electrode size and internal layer number. Spontaneous polarization and strain decreased with increasing electrode size. In addition, the increase of internal layer number brought reduced spontaneous polarization and increased the field-induced strain. Because the actuators structure is designed to stack ceramic layer and electrode layer alternatively, the ceramic-electrode interfaces may act as a resistance to motion of domain wall. To analyze the effect of ceramic-electrode interface, the diffraction intensity ratio of (002) to (200) planes was calculated from X-ray diffraction patterns of samples subjected to a voltage of 200 V. The diffraction intensity ratio of (002) to (200) planes was decreased with increasing electrode size and internal layer number. The diffraction intensity ratio and straining behavior analyses indicate that the Polarization and strain were affected by the amount of 90°domain decreasing with increasing electrode size and internal layer number. Consequently, the change of polarization and displacement with respect to electrode size and layer number is likely to be caused by readiness of the domain wall movement around the interface.

The relationship of phyllosilicate orientation, X-ray diffraction intensity ratios, and c/ b fissility ratios in metasedimentary rocks of the Helvetic zone of the Swiss Alps and the Caledonides of Jämtland, central western Sweden

Phyllosilicate preferred orientations, X-ray diffraction intensity ratios, and c/ b fissility ratios were determined from 23 metasedimentary rocks from the Helvetic zone of the Swiss Alps and from the Caledonides of Jämtland, Sweden. The relationships between these parameters of phyllosilicate orientation depend strongly on the lithology and the cleavage morphology. Differences in orientation direction and in degree of preferred orientation reflect both deformation intensities and lithologies. Whereas polyphase deformed, fine-grained samples generally have phyllosilicates that are oriented parallel to cleavage showing high orientation intensities, phyllosilicates in less deformed and/or coarse-grained rocks are oriented parallel to bedding with low orientation intensities. Weak orientation intensities in samples with phyllosilicates that are oriented parallel to bedding reflect compaction strain. The higher strain in samples with micas and chlorites that are parallel to cleavage is a combination of compaction and tectonic strain due to the development of crenulation cleavage.

Behavior of Electric‐Field‐Induced Strain in PT‐PZ‐PMN Ceramics

In this study, the electric‐field‐induced strain of PT‐PZ‐PMN ceramics was investigated in view of actuator applications under relatively high electric fields. The electric‐field‐induced strain was maximum at the composition x= 39.5, where x denotes the PbTiO3 (PT) content in the formula xPbTiO3·25PbZrO3·(75 ‐ x)Pb(Mg1/3Nb2/3)O3. This composition was 2 mol% richer in PT than the composition at which the piezoelectric constant was maximum. The mechanism of electric‐field‐induced strain at the composition x= 39.5 was analyzed using in situ X‐ray diffraction (XRD) under various electric fields. No change in c/a (tetragonality) was observed. On the other hand, the diffraction intensity ratio of the (200) to (002) planes varied with the electric field. The strain value calculated from changes in the intensity ratio showed good agreement with the measured value, indicating that 90° domain switching dominated in electric‐field‐induced strain for 39.5PbTiO3· 25.0PbZrO3·35.5Pb(Mg1/3Nb2/3)O3.

Effect of lattice distortion on magnetic and electronic state of α″-Fe16N2

We have studied the correlation of the magnetic moment and electronic state of α″-Fe16N2 with the lattice distortion. The epitaxial (α″+α′)-Fe16N2 films were fabricated on Ag(001) underlayers by sputter beam method. With decreasing the film thickness, the unit cell volume of α″-Fe16N2 increased and distinct enhancement of the magnetic moment up to 2.8μB/Fe atom was found. The precisely determined x-ray diffraction intensity ratio Iα″(002)/Iα″(006) apparently reduced with increase of the unit cell volume. From our theoretical calculations, reduction of Iα″(002)/Iα″(006) means increase of the valency of N atoms in α″-Fe16N2. Therefore, it is considered that increase of the magnetic moment of α″-Fe16N2 is attributed to the charge transfer from N to Fe due to lattice expansion effect. This is the first observation showing close relationship between the electronic state and the magnetic moment of α″-Fe16N2.

Characterizations of Cross-Bridges in the Presence of Saturating Concentrations of MgAMP-PNP in Rabbit Permeabilized Psoas Muscle

Several earlier studies have led to different conclusions about the complex of myosin with MgAMP-PNP. It has been suggested that subfragment 1 of myosin (S1)-MgAMP-PNP forms an S1-MgADP-like state, an intermediate between the myosin S1-MgATP and myosin S1-MgADP states or a mixture of cross-bridge states. We suggest that the different states observed result from the failure to saturate S1 with MgAMP-PNP. At saturating MgAMP-PNP, the interaction of myosin S1 with actin is very similar to that which occurs in the presence of MgATP. 1) At 1 degrees C and 170 mM ionic strength the equatorial x-ray diffraction intensity ratio I11/I10 decreased with an increasing MgAMP-PNP concentration and leveled off by approximately 20 mM MgAMP-PNP. The resulting ratio was the same for MgATP-relaxed fibers. 2) The two dimensional x-ray diffraction patterns from MgATP-relaxed and MgAMP-PNP-relaxed bundles are similar. 3) The affinity of S1-MgAMP-PNP for the actin-tropomyosin-troponin complex in solution in the absence of free calcium is comparable with that of S1-MgATP. 4) In the presence of calcium, I11/I10 decreased toward the relaxed value with increasing MgAMP-PNP, signifying that the affinity between cross-bridge and actin is weakened by MgAMP-PNP. 5) The degree to which the equatorial intensity ratio decreases as the ionic strength increases is similar in MgAMP-PNP and MgATP. Therefore, results from both fiber and solution studies suggest that MgAMP-PNP acts as a non hydrolyzable MgATP analogue for myosin.