Density Of Bands Research Articles

Failure mechanics of a wrinkling thin film anode on a substrate under cyclic charging and discharging

Recent experiments show that a thin film anode on a compliant substrate can significantly mitigate mechanical degradation and capacity fading of lithium-ion and sodium-ion batteries in service. The enhanced cycle performance of such a substrate-supported thin film anode is attributed to the wrinkling-induced stress relaxation. While the experimental evidence is suggestive, there lacks a systematic mechanistic study of the wrinkling of the substrate-supported thin film anode and its influence on anode cycle performance. We report a comprehensive study of the charging/discharging induced wrinkling formation and subsequent morphologic evolution of a substrate-supported thin film anode, using theoretical analysis and finite element simulations. We reveal that necking bands may form near wrinkling troughs or peaks and further develop to cause fragmentation of the anode over charging/discharging cycles, a failure mode not reported in the existing literature. The density and distribution of the wrinkling-associated necking bands in the substrate-supported thin film anode can be regulated by the substrate stiffness. Moreover, the wrinkling-induced necking in such a thin film anode can be deferred by regulating the charging capacity. These findings offer new mechanistic understanding of substrate-supported thin film anodes and thus shed light on novel design of high performance anodes in batteries.

The Influence of Finasteride on Mean and Relative Spectral Density of EEG Bands in Rat Model of Thioacetamide-Induced Hepatic Encephalopathy.

Liver failure is associated with a neuropsychiatric syndrome, known as hepatic encephalopathy (HE). Finasteride, inhibitor of neurosteroid synthesis, may improve the course of HE. The aim of our study was to investigate the influence of finasteride on mean and relative power density of EEG bands, determined by spectral analysis, in rat model of thioacetamide-induced HE. Male Wistar rats were divided into groups: (1) control; (2) thioacetamide-treated group, TAA (900mg/kg); (3) finasteride-treated group, FIN (150mg/kg); and (4) group treated with finasteride (150mg/kg) and thioacetamide (900mg/kg), FIN+TAA. Daily doses of FIN (50mg/kg) and TAA (300mg/kg) were administered during 3subsequent days, and in FIN+TAA group FIN was administered 2h before every dose of TAA. EEG was recorded 22-24h after treatment and analyzed by fast Fourier transformation. While TAA did not induce significant changes in the beta band, mean and relative power in this band were significantly higher in FIN+TAA versus control group (p<0.01). TAA caused a significant decline in mean power in alpha, theta, and delta band, and in FIN+TAA group the mean power in these bands was significantly higher compared with control. While in TAA group relative power was significantly decreased in theta (p<0.01) and increased in delta band (p<0.01) versus control, the opposite changes were found in FIN+TAA group: an increase in theta (p<0.01) and a decrease in delta relative power (p<0.01). In this study, finasteride pretreatment caused EEG changes that correspond to mild TAA-induced HE.

Altered Dynamic of EEG Oscillations in Fibromyalgia Patients at Rest.

Previous fMRI findings have shown that chronic pain patients display an altered activation and functional connectivity of the pain network. The aim of the present study was to analyze EEG dynamics in fibromyalgia patients (n = 20) and pain-free controls (n = 18) at rest. Spectral power density, source current density, and intra- and inter-hemispheric coherence were analyzed from 64 EEG channels during 5-minutes eyes-closed rest. Results indicated that fibromyalgia patients displayed reduced power density of the delta EEG band (2-4 Hz) over right insula, right superior and middle temporal gyri as compared with pain-free controls. Fibromyalgia patients also exhibited greater power density than pain-free controls in two segments of the beta band (16-23 Hz and 23-30 Hz) over right middle frontal lobe and midcingulate gyrus. Pain duration in fibromyalgia patients was negatively correlated with delta power from right insula. Greater centro-parietal intra-hemispheric coherence was observed at the left hemisphere on theta (4-8 Hz), and beta-3 (23-30 Hz) frequency bands in fibromyalgia patients than in pain-free controls. Individual differences in depression, anxiety or negative affect did not account for these findings. Fibromyalgia leads to an altered dynamic of the brain network involved in the processing of pain even at rest. Furthermore ,: our results provide further support for the feasibility of resting-state EEG analyses as a clinical biomarker for the characterization of chronic pain states.

Insights into dynamic strain aging under cyclic creep with reference to strain burst: Some new observations and mechanisms part-II: Microstructural aspects

Cyclic creep behavior of 316LN austenitic stainless steel (SS) was investigated at 823K at different combinations of mean stress (σm), stress amplitude (σa) and stress rate. Characteristic strain bursts were observed being attributed to a pronounced influence of dynamic strain aging (DSA). Detailed microstructural investigation carried out through transmission electron microscope (TEM) revealed that dislocation substructure evolving under a process of strain burst during cyclic creep mainly consists of planar deformation bands. The number density of bands was found to be strongly sensitive to σm- σa-stress rate combination employed. An important substructural feature found in this study was the formation of microtwins. Either planar slip or twinning was found to dominate the substructure depending on the loading combination, which was demonstrated through a dislocation distribution map. Dislocation substructure was further correlated with evolution of surface relief studied through atomic force microscopy (AFM) and field emission gun-scanning electron microscopy (FEG-SEM), which depicts the formation of slip markings and nucleation of cracks from persistent slip markings during the course of a strain burst. Finally, well-known theoretical models explaining the mechanism of DSA during tensile deformation were suitably modified for load-controlled scenario and the origin of strain burst as a function of σm or stress rate was explained based on the same. Dislocation density measurements were carried out for specimens undergoing strain burst during cyclic creep, which was utilized for reconstituting the models.

Dissipation and effects of tricyclazole on soil microbial communities and rice growth as affected by amendment with alperujo compost

The presence of pesticides in surface and groundwater has grown considerably in the last decades as a consequence of the intensive farming activity. Several studies have shown the benefits of using organic amendments to prevent losses of pesticides from runoff or leaching. A particular soil from the Guadalquivir valley was placed in open air ponds and amended at 1 or 2% (w/w) with alperujo compost (AC), a byproduct from the olive oil industry. Tricyclazole dissipation, rice growth and microbial diversity were monitored along an entire rice growing season. An increase in the net photosynthetic rate of Oryza sativa plants grown in the ponds with AC was observed. These plants produced between 1100 and 1300kgha−1 more rice than plants from the unamended ponds. No significant differences were observed in tricyclazole dissipation, monitored for a month in soil, surface and drainage water, between the amended and unamended ponds. The structure and diversity of bacteria and fungi communities were also studied by the use of the polymerase chain reaction denaturing gel electrophoresis (PCR-DGGE) from DNA extracted directly from soil samples. The banding pattern was similar for all treatments, although the density of bands varied throughout the time. Apparently, tricyclazole did not affect the structure and diversity of bacteria and fungi communities, and this was attributed to its low bioavailability. Rice cultivation under paddy field conditions may be more efficient under the effects of this compost, due to its positive effects on soil properties, rice yield, and soil microbial diversity.

Evolution of free volume and shear band intersections and its effect on hardness of deformed Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass

Introduction of shear bands in metallic glasses is usually regarded as being responsible for softening metallic glasses. Here we present that hardness of deformed Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass (BMG) exhibits an initial decrease and a subsequent increase with plastic strain. This extraordinary variation of hardness was studied by investigating evolution of shear band intersections and free volume with plastic strain. As plastic strain increases from 6% to 83%, the density of shear bands increases from 0.04 to 0.92 μm−1. Meanwhile, the distribution width of shear band spacings gradually narrows, and the number of intersections between shear bands increases. When plastic strain is larger than 47%, the number of intersections increases faster. Free volume in the deformed BMG at room temperature increases with plastic strain increasing from 6% to 83%. Both free volume induced softening and shear band interaction induced hardening may affect the hardness of the deformed BMG. In the plastic strain range of 0%–47%, free volume induced softening mainly contributes to the initial decrease in hardness with plastic strain. In the plastic strain range of 47%–83%, shear band interaction induced hardening may lead to the increase in hardness with plastic strain, after counteracting free volume induced softening.

Wavelet-based study of valence-arousal model of emotions on EEG signals with LabVIEW.

This paper illustrates the wavelet-based feature extraction for emotion assessment using electroencephalogram (EEG) signal through graphical coding design. Two-dimensional (valence–arousal) emotion model was studied. Different emotions (happy, joy, melancholy, and disgust) were studied for assessment. These emotions were stimulated by video clips. EEG signals obtained from four subjects were decomposed into five frequency bands (gamma, beta, alpha, theta, and delta) using “db5” wavelet function. Relative features were calculated to obtain further information. Impact of the emotions according to valence value was observed to be optimal on power spectral density of gamma band. The main objective of this work is not only to investigate the influence of the emotions on different frequency bands but also to overcome the difficulties in the text-based program. This work offers an alternative approach for emotion evaluation through EEG processing. There are a number of methods for emotion recognition such as wavelet transform-based, Fourier transform-based, and Hilbert–Huang transform-based methods. However, the majority of these methods have been applied with the text-based programming languages. In this study, we proposed and implemented an experimental feature extraction with graphics-based language, which provides great convenience in bioelectrical signal processing.

Urosolenia and Acanthoceras species from Hainan Province, China

Urosolenia and Acanthoceras are reported as cosmopolitan centric genera, but records of these two taxa are infrequent. During an investigation of the diatom flora from Hainan Province, South of China, three Urosolenia and one Acanthoceras species were observed. Based on the morphological and ultrastructural features, we propose these three Urosolenia species as new to Science, named as U. yalongii sp. nov., U. truncata sp. nov. and U. subtenuis sp. nov. Urosolenia yalongii differs from other species such as U. amazonica, U. delicatissima and U. eriensis by its lower density of cingula, and the presence of elongated poroids on the valve and 3–5 teeth on the end of extension. Urosolenia truncata is similar to U. yalongii but it has denser cingula and the blunt ends of the extension make it very distinctive from other known species of the genus. Urosolenia subtenuis can be separated from all other Urosolenia species by its small frustule, lower density of bands and by having 2–3 teeth with a ligula on the tip of the extension. Additionally, one taxon of Acanthoceras resembling A. zachariasii was observed; the Hainan specimens differ from previous descriptions of A. zachariasii by presenting a lower density of cingula and 5–7 teeth at the tip of the extension. Lack of information on the type of this species suggests to avoid determining the Hainan specimens as a separate species.

Corrosion-fatigue properties of plasma-based low-energy nitrogen ion implanted AISI 304 L austenitic stainless steel in borate buffer solution

Abstract AISI 304 L austenitic stainless steel was modified by using the plasma-based low-energy nitrogen ion implantation (PBLEII) at a process temperature of 400 °C for a processing time of 4 h in order to improve the corrosion-fatigue resistance of the austenitic stainless steel. A single high-nitrogen face-centered-cubic phase (γN) layer with a maximal nitrogen concentration of about 25 at.% was formed on the nitrogen-modified austenitic stainless steel. Compared with the original austenitic stainless steel, the γN phase layer on the austenitic stainless steel possessed a significant improvement in corrosion resistance in the borate buffer solution with a pH value of 8.4. The corrosion-fatigue properties of the γN phase layer on the austenitic stainless steel were examined by the push–pull fatigue experiments with a ratio R of tensile and compression of − 1 in the borate buffer solution. The γN phase layer has an increased corrosion-fatigue strength up to 230 MPa from 180 MPa of the original austenitic stainless steel with an apparent increase of about 28%. The corrosion-fatigue crack initiation in the γN phase layer was found as a controllable stage in the fracture process at the interface between the γN phase layer and the austenitic stainless steel matrix with the arc corrosion-fatigue source. Some tiny corrosion-fatigue striations were obtained on the corrosion-fracture surfaces of the γN phase layer. The high density of slip bands and dislocations in the γN phase layer was able to prevent the crack initiation and propagation, leading to improvement of the corrosion-fatigue properties in the borate buffer solution.

Surface mechanical attrition treated AISI 304L steel: role of process parameters

In the present work, AISI 304L steel was used to investigate the effect of surface mechanical attrition treatment (SMAT) parameters on the hardness and microstructure. The surface modified by SMAT was examined using an optical microscope, SEM, electron backscattered diffraction, X-ray diffraction and microhardness measurements. The surface hardness of specimens was more than two times the hardness of non-treated core for all SMAT parameters. High density of shear bands (which formed nanosize rhombic blocks) was observed near the treated specimen surface. Density of shear bands was reliant on the size and number of balls. Deformation induced martensite (α′) was formed in surface mechanical attrition treated region. Volume per cent of α′ was enhanced with an increase in SMAT duration and number of balls. However, it was reduced with an increase in gap between vibrating plate and specimen surface. Microstructure evolution at various SMAT parameters was effectively explained using newly introduced terminology called ‘peening intensity’.

Ultrasound patterning technologies for studying vascular morphogenesis in 3D.

Investigations in this report demonstrate the versatility of ultrasound-based patterning and imaging technologies for studying determinants of vascular morphogenesis in 3D environments. Forces associated with ultrasound standing wave fields (USWFs) were employed to non-invasively and volumetrically pattern endothelial cells within 3D collagen hydrogels. Patterned hydrogels were composed of parallel bands of endothelial cells located at nodal regions of the USWF and spaced at intervals equal to one half wavelength of the incident sound field. Acoustic parameters were adjusted to vary the spatial dimensions of the endothelial bands, and effects on microvessel morphogenesis were analyzed. High-frequency ultrasound imaging techniques were used to image and quantify the spacing, width and density of initial planar cell bands. Analysis of resultant microvessel networks showed that vessel width, orientation, density and branching activity were strongly influenced by the initial 3D organization of planar bands and, hence, could be controlled by acoustic parameters used for patterning. In summary, integration of USWF-patterning and high-frequency ultrasound imaging tools enabled fabrication of vascular constructs with defined microvessel size and orientation, providing insight into how spatial cues in 3D influence vascular morphogenesis.

Continuous measurement for optical density of visible band of solar blind UV filters

为实现SolarBlind（日盲紫外）滤光片光密度在可见光谱段的高精度连续测试，搭建了以氙灯配合单色仪作为光源、使用单光子计数器作为探测器的测试系统，并对该系统的误差进行分析。系统主要装置有氙灯与单色仪组合的光源，标准衰减装置和单光子计数器；以替代法为基础进行测试，将由单光子计数器探测到的衰减后的计数值作为参考计数值替代光源的初始计数值，通过运算得到滤光片的可见光谱段光密度；该测试系统将滤光片光密度的测试动态范围扩展到0~-11OD，实现了可见光谱段内进行连续光谱测量的功能，且降低了系统的测试误差。与使用窄带LED作为光源的测试系统相比，测试不确定度由2%降低至0.5%，相对重复性误差由0.2％ 降低至0.13％。

Nb掺杂SrTiO&lt;sub&gt;3&lt;/sub&gt;的光学特性研究

本文主要根据第一性原理的方法并应用Material Studio中的CASTEP模块分别对SrTiO3以及Nb掺杂SrTiO3两种材料的能带结构和态密度进行了仿真计算，然后对其进行相应的分析最后得出其光学特性。分析结果表明，未掺杂时SrTiO3的价带顶主要是由O原子的2p态组成，它的导带底则主要由Ti 3d态贡献；SrTiO3是间接跃迁能带结构，带隙宽度约为1.8 eV。掺杂后系统的带宽为2.02 eV，为直接跃迁能带结构，且与掺杂前相比系统的折射率与静介电常数都有不同程度的增大。 In this paper, based on first-principles method and application of the Material Studio CASTEP module, energy band structure and density of SrTiO3 and Nb-doped SrTiO3 materials were simulated, and we analyzed their energy bands structure and density of states and got the conclusion of optical properties. The analysis results show that the undoped SrTiO3 valence-band maximum is mainly composed by the 2p state of atom O, while the conduction band is mainly contributed by Ti 3d state; SrTiO3 is an indirect transition band structure, and the band width is about 1.8 eV. After doping, the SrTiO3 becomes a direct transition band structure with the band width of 2.02 eV, and the refractive index and static dielectric constant increase in different extent compared with before.

Effect of Aspect Ratio on the Evolution of Shear Bands in Zr61.7Al8Ni13Cu17Sn0.3 Bulk Metallic Glass

Zr61.7Al8Ni13Cu17Sn0.3 bulk metallic glass samples with different aspect ratios in the range of 0.25–2.25 were deformed by compression, and the effect of aspect ratio on the evolution of shear bands was investigated. It is found that for the deformed Zr61.7Al8Ni13Cu17Sn0.3 bulk metallic glass, the average shear band spacing decreases and the shear band density increases monotonically as the aspect ratio increases from 0.25 to 2.25. A minimal average shear band spacing of 0.478 µm is achieved for the sample with an aspect ratio of 2.25. In addition, the fractions of shear bands with spacings below 100 and 50 nm are about 12.84% and 6.76%, respectively, for the sample with an aspect ratio of 2.25. The reason for the formation of a higher density of shear bands can probably be attributed to the increase of the driving force for the sample with a larger aspect ratio.

Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films.

Abstract 17230: Early Continuous EEG Biomarkers Predicts Neurologic Outcome in Post-cardiac Arrest Rats

Introduction: Hypothermic targeted temperature management (TTM) has greatly improved post-cardiac arrest patient outcomes, but also makes prognostication more difficult. In this study, we tested the hypothesis that early continuous EEG biomarkers are associated with neurologic outcome in post-cardiac arrest rats treated with normothermic and hypothermic TTM. Methods: Male rats were instrumented for continuous telemetric EEG (cEEG) recording and then subjected to 8-minute asphyxia cardiac arrest. Eight rats that achieved ROSC underwent either normothermic or hypothermic TTM (37 ± 0.5 °C or 33 ± 0.5 °C) for 24 hours and cEEG monitoring up to 72 hours. Quantitative EEG analysis determined the power density of delta (0.1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz) and sigma (13-18 Hz) frequency bands in all 10 second windows. The mean spectral power and Spearman correlation with time for the first 12 hours after return of spontaneous circulation (ROSC) were calculated and correlated with best neurologic function score (NFS) and survival with good NFS (NFS ≥ 450 out of 500). Results: Over all rats tested, the mean delta band power in the first 12 hours after ROSC was inversely correlated with best neurologic function score and associated with poor outcome (Table and Figure). There was no statistical difference in other frequency bands. Similar findings were present when stratifying into normothermic and hypothermic treatment groups. Conclusions: This study suggests that, the early power density of delta frequency bands from cEEG is a potential predictor of neurologic outcome in a mixed population of rats treated with normothermic and hypothermic TTM.

Plasticity enhancement in bulk metallic glasses by electroless plating with Ni-P amorphous films

In this study Electroless plating is used to deposit amorphous Ni-P films on the surface of the Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit.1) bulk metallic glasses (BMGs) with different pH values and film thicknesses. The special amorphous/amorphous structure exhibited large plasticity. The plastic strain is 10.6% for the coated pillars with a coating thickness of 86.5μm, which is 5.9 times of 1.8% of the bare Vit.1 pillars. The amorphous Ni-P films provide high radial confinement stress, which leads to more homogeneous formation of a high density of smaller shear bands at the Ni-P/Vit.1 interface. The technique provides an effective way to enhance the plasticity without obvious sacrifice of the yielding strength for BMGs at room temperature.

Structural instability and ground state of the U2Mo compound

This work reports on the structural instability at T = 0 °K of the U2Mo compound in the C11b structure under the distortion related to the C66 elastic constant. The electronic properties of U2Mo such as density of states (DOS), bands and Fermi surface (FS) are studied to understand the source of the instability. The C11b structure can be interpreted as formed by parallel linear chains along the z-directions each one composed of successive U–Mo–U blocks. Hybridization due to electronic interactions inside the U–Mo–U blocks is slightly modified under the D6 distortion. The change in distance between chains modifies the U–U interaction and produces a split of f-states. The distorted structure is stabilized by a decrease in energy of the hybridized states, mainly between d-Mo and f-U states, together with the f-band split. Consequently, an induced Peierls distortion is produced in U2Mo due to the D6 distortion. It is important to note that the results of this work indicate that the structure of the ground state of the U2Mo compound is not the assumed C11b structure. It is suggested for the ground state a structure with hexagonal symmetry (P6 #168), ∼0.1 mRy below the energy of the recently proposed Pmmn structure.

Investigation and simulation of the structural and electronic properties of LiF:Mg, LiF:Cu, LiF:P nano-layer dosimeters

In this study, electronic structure of lithium fluoride thin films in pure state and doped with magnesium (Mg), copper (Cu) and phosphorus (P) impurities was studied using WIEN2K Code. The structural and electronic properties of two LiF thin films with 1.61 and 4.05 nm thicknesses were studied and compared. Results show that the distance of atoms in the surface and central layers of pure LiF are 1.975 and 2.03 nm, respectively. Electronic density of the valence band around the surface atoms is greater than that around middle atoms of the supercell. The band gap of bulk LiF is 9 eV. But, in the case of thin films, it is reduced to 2 eV. Electronic and hole-traps were not observed in composition of LiF thin films doped with Mg and P with 1.61 and 4.05 nm thickness and in fact, metallic properties were observed. When Cu atoms were doped in composition of an LiF thin film, the thin film was converted to semiconductor.

Bacteria community in different aged Coptis chinensis planting soil revealed by PCR-DGGE analysis

In order to reveal the cause of disease occurred in the process of Coptis chinensis growth, this paper studied the bacterial species diversity index of different aged rhizospheric and non-rhizospheric soil planting normal or sick C. chinensis by using PCR-DGGE technique. The representative DGGE bands were chosen to be cloned, and sequenced, the phylogeny were constructed. The results showed that the bacterial communities were very different between the normal and diseased soil samples of C. chinensis, and the diversity index (H) of diseased soil samples were higher than that of normal soil samples. Sequencing analysis of representative cloned DGGE bands showed that the unculturable bacteria were the dominant groups, and bacteria belonged to genus Bacillus, Acidovorax, Acinetobacter, uncultured Kluyvera, and uncultured Comamonas were also existing, but the reported plant pathogenic bacteria were not found in the C. chinensis planting soil. The density and brightness of clone band d in diseased soil samples was higher than that in normal soil sample, and sequencing analysis showed that it belonged to genus Acidovorax. Obviously, during the process of C. chinensis growth, the rhizospheric bacteria population changed, and the quantity of bacteria belong Acidovorax increased, which probably resulted in the disease occurred during C. chinensis growth.