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In this article, we address the trajectory tracking problem using the learning from demonstration (LFD) method. By using the LFD method, the parameter adjusting problem in the tracking controller is avoided. Consequently, a strategy can be provided to users with limited parameter adjusting experience. The kinematic tracking problem is formulated as a second-order system and the objective is to simultaneously reduce the errors in position and velocity. The extreme learning machines (ELM) algorithm is applied in the controller design. The velocity and position are utilized as the inputs and the output is the robot corrected kinematic movement. The controller parameters are learned from the desired human or programming demonstrations taking into consideration the stability constraints. In this work, we analyze the system local and global asymptotic stability in detail. The effectiveness of the proposed strategy is demonstrated by simulation comparisons and a practical experiment using a KUKA robot manipulator. [ABSTRACT FROM AUTHOR]

Abstract: Perovskite 0.4Bi(Zn1/2Ti1/2)O3–0.6PbTiO3 (BZT–PT) powders were successfully synthesized from precursor oxides using a high-energy planetary ball milling. The phase development of the powders during milling was studied by means of X-ray diffraction and Raman scattering techniques. The microstructure of the powders was characterized using transmission electron microscopy, and the thermal behavior was studied as well. The results reveal that after 15 h of milling the formation of BZT–PT phase can be completed and submicron agglomerates of small crystallite sized ~12 nm are present in the powders. However, further prolonging the milling time to 25 h leads to the amorphization of the BZT–PT phase. [Copyright &y& Elsevier]

• Ex-situ observations on crack initiation and propagation behavior are performed. • The relation between hydrides crack and the maximum principal stress is investigated. • The effect of circumferetial and radial hydrides on fatigue cracking is illustrated. • Fatigue crack propagation is facilitated along the Zr matrix-hydrides interface. • Fatigue crack nucleation and propagation proceeds along slip bands in Zr matrix. Zirconium (Zr) alloys, which are widely used as the fuel cladding tubes in the nuclear industry, suffer from the hydrogen embrittlement issues resulting from the precipitation of brittle hydrides. The fatigue crack initiation and propagation behavior at room temperature in a Zr-Sn-Nb-Fe alloy tube material containing the hydrides of the axial and hoop orientations are investigated. The results show that the fatigue cracking initiates at the hydrides. The sensitivity of hydride-induced cracking is largely dependent on the hydride orientation with respect to the applied stress direction. When the hydride platelets are oriented with their longitudinal direction perpendicular to the applied stress, the hydrides facilitate the development of fatigue cracking in the tube material. A micromechanical stress analysis qualitatively describes the stress state of the hydrides subjected to the fatigue loading. The analysis shows that the hydrides tend to crack along the direction perpendicular to the maximum principal stress. The fatigue crack propagation under cyclic shear stress is found to be facilitated along the Zr matrix–hydrides interface, in contrast to the ductile Zr matrix which may blunt the development of crack tips. Further fatigue crack nucleation and propagation proceeds along the slip bands in the Zr matrix at significant fatigue loading cycles, leading to the eventual fatigue failure of the investigated cladding tubes with a relatively low hydrogen content (~260 ppm). [ABSTRACT FROM AUTHOR]

In the development of atomic physics, laser sources with Frequencies corresponding to atomic transition and high stability are essential. The Faraday laser is a special diode laser using the Faraday anomalous dispersion optical filter (FADOF) to realize frequency selection, so the output laser frequency is automatically limited to the atomic Doppler broadening. However, the frequency of a Faraday laser corresponds to the range around only one atomic hyperfine transition. Here, we realize a switchable Faraday laser with two isotopes laser frequencies corresponding to 85Rb 5 2 S 1 / 2 (F = 3) → 5 2 P 3 / 2 and 87Rb 5 2 S 1 / 2 (F = 2) → 5 2 P 3 / 2 transitions based on a single isotope 87Rb-FADOF. The laser has good robustness against the fluctuation of diode current and temperature, with wavelength fluctuating within 0.8 pm from 16 to 30 °C of diode temperature, and has a free-running linewidth of 18 kHz. We also lock the laser frequency to the two cycling transitions of 85Rb 5 2 S 1 / 2 (F = 3) → 5 2 P 3 / 2 (F ′ = 4) and 87Rb 5 2 S 1 / 2 (F = 2) → 5 2 P 3 / 2 (F ′ = 3) by the modulation transfer spectroscopy technique. The Allan deviation of the residual error signal is 3 × 10 − 14 / τ , and the frequency stability of the beat detection reaches 2.8 × 10 − 12 at 1 s integration time. This 780 nm switchable Faraday laser expands the application scenarios of Faraday lasers, which can be used in laser cooling atoms, optical frequency standards, and other quantum precision measurement fields. [ABSTRACT FROM AUTHOR]

Background: Flathead fishes of the genus Platycephalus are economically important demersal fishes that widely inhabit the continental shelves of tropical and temperate sea waters. This genus has a long history of taxonomic revision, and recently four Platycephalus species (Platycephalus sp. 1, Platycephalus sp. 2, P. indicus, and P. cultellatus) in the northwestern Pacific Ocean (NWP) have been recognized and redescribed. However, many aspects of their systematics and evolutionary history are unclear. Results: A total of 411 individuals were sampled from 22 different sites across their distributions in the NWP. Three mitochondrial loci were sequenced to clarify the phylogeny and phylogeographic history of the fishes. The results showed significant differentiation of four Platycephalus species in the NWP with well-supported clades in which Platycephalus sp. 1 and Platycephalus sp. 2 were the closest, clustered with P. cultellatus, while their genetic relationship with P. indicus was the furthest. There were significant genealogical branches corresponding to P. indicus but not to other Platycephalus lineages. We further examined the phylogeographic patterns of 16 Platycephalus sp. 1 populations along the coastlines of China and Japan. A total of 69 haplotypes were obtained, with 23 shared among populations. One dominant haplotypic group, with a modest lineage structure and low levels of haplotype diversity and nucleotide diversity, was observed among Platycephalus sp. 1 populations. The demographic history reconstruction suggested a Platycephalus sp. 1 population expansion event dating back to the late Pleistocene. Conclusions: Distributional rang variations may be the crucial factors shaping the genetic relationships of the genus Platycephalus. Reproductive schooling and potential egg/larval dispersal ability, coupled with the effects of ocean currents, are responsible for the present phylogeographic pattern of Platycephalus sp. 1. [ABSTRACT FROM AUTHOR]

• Fatigue short crack propagation rate exhibits remarkable fluctuations. • Multiple slip is activated, causing the crack retardation or deflection. • Fatigue short cracks are shown to favorably propagate through the grain boundaries oriented with the twist angle less than 40°. • Improved analytical modeling for prediction of the fatigue short crack propagation is presented. The microstructural sensitivity of fatigue short crack path and its propagation rate in a Ni-based superalloy GH4169 manufactured by laser powder bed fusion (LPBF) was investigated at room temperature. In-situ digital image correlation (DIC) observation and post-mortem microstructural analysis around the crack path were performed. The results show that the intragranular cracks developed in the shear cracking mode are closely aligned along the activated slip bands in the γ -matrix grains with the crystallographic characteristics of parallel to the γ -{111} slip planes. Multiple slip was also activated, causing the crack retardation or deflection. Low-angle grain boundaries and subgrain boundaries were shown to cause deflections of intragranular cracking, while high-angle grain boundaries significantly arrested the short crack propagation. Moreover, the resistance of grain boundaries to short cracking was assessed using combined metrics including the crystallographic and microstructural parameters of twist angle, the Schmid factor and the geometrical compatibility factor. These site-specific microstructural analyses around the crack path provide insights into the microstructural origins of resistance to the short crack propagation as well as an interpretation of the observed significant fluctuations in the crack propagation rate. [Display omitted] [ABSTRACT FROM AUTHOR]

In response to the significant ecological damage caused by unsustainable mining practices in the Qilian Mountains, ecological restoration projects have been undertaken in recent years. Analyzing the changes in soil microbial communities during the restoration process of mine meadows helps to reveal the mechanism of the restoration process in alpine mining areas. To explore the characteristics of soil microbial community distribution and their relationships with soil environmental factors during the restoration of alpine grasslands in the Qilian Mountains, we conducted surveys and analyses in two restoration levels low restoration (LR) and high restoration (HR) in the eastern Qilian Mountains, along with an undisturbed natural grassland control (NG). We found that as the degree of high-altitude mining area recovery increases, there were significant increases in vegetation cover, vegetation height, above-ground biomass, vegetation Shannon–Wiener index, soil organic carbon (SOC), soil water content (SWC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available phosphorus (AP), and available nitrogen (AN). Conversely, soil pH and electrical conductivity (EC) significantly decreased, with soil pH decreasing from 6.93 to 4.13. Restoration of high-altitude mining area grasslands significantly alters the distribution and composition of soil bacteria and fungi, while the impact on soil microbial community changes was not significant. Notably, with increasing recovery level, the dominant bacterial phyla are Acidobacteria and Proteobacteria, while the dominant fungal phyla are Ascomycota and Basidiomycota. These results indicate that changes in vegetation and soil properties both affect the composition of soil microbial communities, with soil properties having a greater influence. Soil fertility and nutrient levels emerge as the primary drivers influencing soil microbial composition communities and the degree of high-altitude mining area grassland recovery. [ABSTRACT FROM AUTHOR]

As a promising branch of optical absorption-based photoacoustic microscopy, photoacoustic dermoscopy (PAD) can provide manifold morphologic and functional information in clinical diagnosis and the assessment of dermatological conditions. However, most PAD setups are insufficient for clinical dermatology, given their single optical resolution (OR) or acoustic resolution (AR) mode, which results in poor spatiotemporal resolution or imaging depth for visualizing the internal texture of skin. Here, a switchable optical and acoustic resolution photoacoustic dermoscope (S-OR-ARPAD) system is developed, which provides a smooth transition from OR mode in microscopic imaging of superficial skin layers to AR mode when imaging at greater depths within intensely scattering deep skin layers. The lateral resolution can be seamlessly switched between 4.4 and 47 μm as the maximum imaging depth is switched between 1.2 and 1.8 mm for skin imaging. Using the S-OR-ARPAD, we identified the two distinct resolution modes responsible for resolving features of different skin layers and demonstrated the fine structures with strong contrast in the stratum corneum, dermal papillae, and microvascular structures in the horizontal plexus by imaging the healthy human skin at different locations. [ABSTRACT FROM AUTHOR]

The issue of heavy metal pollution has gradually emerged as a significant global concern. Microbial fuel cells (MFCs) hold immense potential for clean energy production and pollutant treatment. However, their limited power generation efficiency hampers the large-scale implementation of MFCs. The porous microstructure of biochar and the excellent physical and chemical properties of rutile render both materials promising catalysts with positive potential. In this study, we employed biochar as a carrier for rutile to fabricate a novel rutile–biochar (Rut-B) composite material, investigating its efficacy in enhancing MFC power generation efficiency as a cathode catalyst, as well as its application in heavy metal pollutant degradation. Scanning electron microscopy (SEM) results confirmed the successful preparation of biochar-loaded rutile composites. The MFC achieved maximum current density and power density values of 152.26 mA/m2 and 9.88 mW/m2, respectively—an increase of 102.7% and 224% compared to the control group without the addition of Rut-B. Furthermore, the biochar-loaded rutile MFC exhibited excellent performance in degrading heavy metal pollutants; within 7 h, the Pb2+ degradation rate reached 92.4%, while the Zn2+ degradation rate reached 84%. These rates were significantly higher than those observed in the control group, by factors of 437.2% and 345%, respectively. The cyclic degradation experiments also demonstrated the outstanding stability of the system over multiple cycles. In summary, this study successfully combined natural rutile with biochar to create an efficient electrode catalyst that not only enhances electricity generation performance but also provides an environmentally friendly and cost-effective approach for remediating heavy metal pollution. [ABSTRACT FROM AUTHOR]

The study of atomic physics has been greatly influenced by the development of high-stability diode lasers whose output corresponds to the atomic transition. Recently, an atomic filter laser "Faraday laser" shines on stage, owing to its great robustness to the fluctuation of the diode parameters and potentially higher tolerance to vibration. However, cost reduction and portability require the Faraday laser to have a more compact structure. Here, we report on the development of a promising atomic filter laser—a "Voigt laser"—using a Voigt anomalous dispersion optical filter (VADOF) as the frequency-selective element, which has a structural advantage in miniaturization. The influencing factors toward the VADOF are investigated in detail to produce a parameter set for the best performance of a Voigt laser. In this case, the Voigt laser has great robustness to the fluctuation in the diode current and temperature, where the wavelength fluctuation is ±0.5 pm with the variation of the diode parameters (diode current: 73–150 mA and diode temperature: 12–30 °C). In addition, the wavelength of the Voigt laser fluctuates about ± 0.5 pm for 48-h free-running operation and shows excellent reproducibility without manual adjustment. The laser system developed here provides a stable and reliable laser source for substantially improving existing technologies such as the atomic clock, electromagnetically induced transparency, and laser cooling of atoms. [ABSTRACT FROM AUTHOR]

The 3′-untranslated region (3′-UTR) of PD-L1 is significantly longer than the coding sequences (CDSs). However, its role and regulators have been little studied. We deleted whole 3′-UTR region by CRISPR-Cas9. Prognostic analysis was performed using online tools. Immune infiltration analysis was performed using the Timer and Xcell packages. Immunotherapy response prediction and Cox regression was performed using the R software. MicroRNA network analysis was conducted by the Cytoscape software. The level of PD-L1 was significantly and dramatically up-regulated in cells after deleting the 3′-UTR. Additionally, we discovered a panel of 43 RNA-binding proteins (RBPs) whose expression correlates with PD-L1 in the majority of cancer cell lines and tumor tissues. Among these RBPs, PARP14 is widely associated with immune checkpoints, the tumor microenvironment, and immune-infiltrating cells in various cancer types. We also identified 38 microRNAs whose individual expressions are associated with PD-L1 across different cancers. Notably, miR-3139, miR-4761, and miR-15a-5p showed significant associations with PD-L1 in most cancer types. Furthermore, we revealed 21 m6A regulators that strongly correlate with PD-L1. Importantly, by combining the identified RBP and m6A regulators, we established an immune signature consisting of RBMS1, QKI, ZC3HAV1, and RBM38. This signature can be used to predict the responsiveness of cancer patients to immune checkpoint blockade treatment. We demonstrated the critical role of the 3′-UTR in the regulation of PD-L1 and identified a significant number of potential PD-L1 regulators across various types of cancer. The biomarker signature generated from our findings shows promise in predicting patient prognosis. However, further biological investigation is necessary to explore the potential of these PD-L1 regulators. [ABSTRACT FROM AUTHOR]

This article presents the heat conduction analysis for irregular functionally graded material (FGM) with temperature-dependent material properties. For irregular FGM geometries, the meshless weighted least-square (MWLS) method is easy to model, implement, and interpolate those irregularly distributed field variables. To solve the heat conduction problem coupled with temperature-dependent FGM, the Laplace's equilibrium equation and boundary condition become nonlinear. Thus, the Kirchhoff transformation is employed to convert the nonlinear problem to linear solution. MWLS method as a pure meshless analysis is then used to solve the linear equation of FGM geometries. Next, the temperature field is obtained by the inverse Kirchhoff transformation. Finally, the accuracy and effectiveness of the method were demonstrated by several numerical cases. [ABSTRACT FROM AUTHOR]

Abstract Background Animal studies suggest polybrominated diphenyl ethers (PBDEs) may be obesogens. However, epidemiologic studies investigating childhood exposure to PBDEs and adiposity are limited, with several reporting an inverse association. Objectives To investigate associations between repeated childhood PBDE concentrations and adiposity measures at age 8 years. Methods We examined 206 children from the Health Outcomes and Measures of the Environment Study, a birth cohort in Cincinnati, OH (2003–2006). Serum PBDEs were measured at ages 1, 2, 3, 5, and 8 years. We used multiple imputation to estimate missing PBDE concentrations. At 8 years, we measured weight, height, waist circumference, and body fat percentage. We used multiple informant models to estimate age-specific associations between PBDEs and adiposity measures. Results We observed significant inverse associations between BDE-153 with all adiposity measures that became increasingly stronger with later childhood measurements. A 10-fold increase in BDE-153 at ages 1 and 8 years was associated with 2% (95% CI −3.9, −0.1) and 7% (95% CI −9.1, −4.7) lower body fat, respectively. No statistically significant associations were found with BDE-28, -47, -99, or -100. Child sex modified some associations; inverse associations between BDE-153 and body fat were stronger among boys, while positive and null associations were noted among girls. Conclusions Childhood BDE-153 concentrations were inversely associated with adiposity measures and these associations became stronger as BDE-153 measurements were more proximal to adiposity measures. Inverse associations could be attributed to reverse causality arising from greater storage of PBDEs in adipose tissue of children with higher adiposity. Highlights • Findings do not support postnatal PBDEs are associated with increased adiposity. • BDE-28, -47, -99, -100, and ∑PBDEs were not associated with adiposity at 8 years. • There was a pattern of inverse associations between BDE-153 and adiposity measures. • Child sex modified BDE-153 associations, with decreases in body fat % in males, but not in females. • Reverse causality may have resulted in inverse associations. [ABSTRACT FROM AUTHOR]

Abstract Background Toxicological studies highlight the potential neurotoxicity of perfluoroalkyl substances (PFAS) during fetal development. However, few epidemiological studies have examined the impact of childhood PFAS on neurodevelopment. Methods We employed data from 208 children in the Health Outcomes and Measures of the Environment Study, a birth cohort (Cincinnati, OH), to examine associations of six serum PFAS concentrations measured at 3 and 8 years with executive function assessed at 8 years using the validated parent-completed Behavior Rating Inventory of Executive Function survey. We used multiple informant models to identify susceptible windows of neurotoxicity to PFAS and executive function. We investigated trajectories of PFAS concentrations and whether sex modified these associations. Results Each ln-increase in perfluorononanoate (PFNA) at 8 years was associated with a 3.4-point increase (95% CI 0.4, 6.3) in metacognition score, indicating poorer function. Children with PFNA above the median at 8 years had poorer global executive functioning compared to children with concentrations consistently below median levels (β = 6.5, 95% CI 0.2, 12.9). Higher concurrent PFNA was associated with poorer behavior regulation among males, while associations among females were null (p PFNA × sex = 0.018). Children with higher concurrent perfluorooctanoate (PFOA) had increased odds of being at risk of having clinical impairments in metacognition (OR = 3.18, 95% CI 1.17, 8.60). There were no associations between perfluorooctane sulfonate and perfluorohexane sulfonate and executive function. Conclusions PFNA and PFOA at 8 years, but not 3 years, may be related to poorer executive function at 8 years. Results need to be confirmed in cohort studies with larger sample sizes. Highlights • PFAS concentrations at age 3 years were not associated with executive function at age 8 years. • Concurrent PFNA was associated with impairments in metacognition and global executive function at 8 years. • A sexually dimorphic relationship may be present, with males more sensitive to PFNA neurotoxicity. • Childhood PFNA and PFOA, to a lesser extent, may be neurotoxic with regard to executive function. [ABSTRACT FROM AUTHOR]

In the view of the problem of delayed hydride cracking via hydrogen embrittlement of fuel claddings of the nuclear industry, a Zr-50D alloy is prepared by heating Zr powder with gaseous D2 (pressure furnace, 573 K, 1.9 bar, 10 h). [ABSTRACT FROM AUTHOR]

A trend in the development of geophysics is to seek wave theory closer to the physical reality and derive corresponding wave equations to achieve highly accurate forward modeling, imaging, and inversion of complex structures. The generalized continuum mechanics (GCM) theory enriches the context of the conventional continuum mechanics theory by introducing the additional characteristic length scale parameters to represent the microstructural properties of the medium, and the asymmetric elastic wave equations derived from GCM theory can handle the influence of heterogeneity of a medium caused by the microstructural interactions on the propagation of seismic waves. To date, there are few studies on the numerical and analytical solutions of the elastic wave equations derived from the GCM theory, especially in the frequency band of seismic exploration. In addition, there are few studies in the existing literature that incorporate multiple theories and methods of the GCM theory into an integrated frame. In this paper, we introduce the concept of the multi-scale microstructural interactions and construct the quantitative relationship between the characteristic length scale parameter of the medium and the characteristic length scale parameter of the micro-pore reflecting the micro-pore structures, and then integrate the modified couple stress theory and the one-parameter second strain gradient theory into a unified framework for numerical modeling and analysis. [ABSTRACT FROM AUTHOR]

The effects of silicate glass particle size and Y 3 Al 5 O 12 : Ce3+ (YAG: Ce3+) phosphor doping concentration on the optical properties of phosphor-in-glass (PiG) samples were investigated. When the average particle size of glass powder was 160, 100, 60, and 30 μm, the transmittance of silicate glass with a thickness of 0.6 mm was 68%, 78%, 62%, and 54%, respectively. With the mixing of 4 wt% YAG: Ce3+ phosphor in each component of silicate glass, the transmitted luminous flux of PiG gradually increased with the increase of transmittance, reaching a maximum of 179.5 lm. Simultaneously, we found that with the increase in transmittance, the photoluminescence (PL) intensity of PiG gradually decreased; however, the total luminous flux of PiG has independent of transmittance. When the doping concentration of YAG: Ce3+ phosphor was 4 wt%, PiG achieved a maximum efficient white light emission of 212.61 lm/W under blue laser excitation at 2.31 W. All results indicate the outstanding feasibility of the prepared YAG-PiG in high-power/high-brightness white light-emitting diodes (WLEDs). [ABSTRACT FROM AUTHOR]

White-light diodes (WLEDs) are widely used in high-brightness applications owing to their outstanding advantages. However, current methods for preparing commercial WLEDs significantly deteriorate their optical properties and limit their use in high-power applications. To address this, inorganic materials, such as phosphor-in-glass (PiG), have been recently investigated as practical alternatives. In this study, a series of high-efficiency white-emitting PiG samples were prepared by mixing silicate glass powders with different particle size distributions and different concentrations of Y3Al5O12:Ce3+ (YAG:Ce3+) phosphors. The microstructure, transmittance, and photoluminescence properties of PiG were investigated. When the glass powder with the particle size ranges of 75–150 and 30–48 μm were mixed, at a ratio of 94 : 6, a silicate glass with a thickness of 0.8 mm and a maximum transmittance of 75% in the visible range was obtained. Under excitation with a 450 nm blue-light laser diode, PiG produced white light with a total luminescence efficiency of 194.64 lm W−1 and a total luminous flux of 623.9 lm. These results demonstrate that the optical performance of PiG can be effectively adjusted by adjusting the particle size distribution of silicate glass powder and the mixing concentration of the YAG:Ce3+ phosphor, thereby providing a tuning pathway for smart white-light devices. [ABSTRACT FROM AUTHOR]

The p - n heterostructures materials are currently used in photoluminescence, electro-chromic devices, photocatalysts and gas sensors due to increasement of the material defect sites at the interface. In this report, we successfully obtain the SnO-SnO 2 p -N ( E gp  <  E gn ) heterostructures by a facile hydrothermal strategy and annealing condition (500 °C). With the as synthesized samples present a morphology of nanosheet n -type SnO 2 crystals dispersed on the edge of similar square p -type SnO crystals. This p -N heterostructural sensor exhibits excellent performances for NO 2 sensing at room temperature in terms of fast response time, relative sensing selectivity, high sensitivity, and low LOD (the limit of detection) (0.1 ppm) by a stable and repeatable response pattern. The superior sensing properties can be attributed to three aspects that the heterojunction valence band offsets (Δ E V  = 3.31 eV) is narrow, unique structure, and the intrinsic ‘O’ vacancies creating defect states close to the conduction band minimum. Further, the plausible formation growth and gas sensing mechanism of the novel SnO-SnO 2 p -N heterostructures are discussed, providing a considerable margin for employing them in gas sensors. [ABSTRACT FROM AUTHOR]

In this work, well-defined cedar-like SnO 2 hierarchical micro-nanostructures have been successfully synthesized through a facile low-temperature hydrothermal method. XRD, SEM, TEM and HRTEM were carried out to investigate morphology and structure of as-obtained products. The morphology can be tailored by modulating the reaction temperature and annealing temperature. It is observed that the cedar-like SnO 2 micro-nanostructure are composed of two parts: the “trunk” and “leaves”. The trunk is composed of a hexagonal-pyramid, and the leaves are constructed by numerous ordered triquetrous nanosheets. As-fabricated cedar-like SnO 2 micro-nanostructure based sensors exhibit fast response time (<1 s)/recovery time (13 s), high sensitivity, good repeatability, and good sensing selectivity towards formaldehyde gas at lower working temperatures. A possible reaction formation mechanism of the cedar-like micro-nanostructure and a morphology-dependent sensing mechanism are proposed. [ABSTRACT FROM AUTHOR]

Surgery represents the mainstream therapeutic modality in oncology. Aggressive radical surgery to achieve no residual tumor would improve survival, which is mainly affected by vascular involvement and accuracy of judging the negative margin of tumor resection. However, there is currently no intraoperative tool that can simultaneously perform microscopic analysis of the peritumoral vasculature in vivo and the surgical margin pathology of the tumor ex vivo, which leads to the randomness of one-time complete resection of the tumor, and the patient may have to undergo secondary surgery. To address this critical need, we developed a 532/266 nm dual-wavelength photoacoustic (PA) microscopy imaging (532/266-PAI) system that enables both in vivo tumor regional vascular involvement analysis and pathological margin assessment of fresh ex vivo tumor samples. A mammary tumor animal model was established to mimic the process of tumor resection, from in vivo imaging vascular involvement of tumor to intraoperative judgment of negative tumor margins. It is proved that the 532/266-PAI technology can identify the tumor vascular involvement through vascular visualization, determine the surgical plan, and then judge whether the tumor is completely removed through ultraviolet PA (UPA) tumor pathological imaging. Re-excision and secondary margin evaluation are performed when margin positive is diagnosed in the intraoperation UPA imaging. The 266/532-PAI technique has great potential for complete tumor resection in surgical navigation. [ABSTRACT FROM AUTHOR]

• DHM-FDEM for reproducing rock meso-macro mechanical behavior with acceptable computational costs is proposed. • Upscale elements assembly to establish connections between rock meso- and macro- mechanical properties is constructed. • A data-driven method to predict rock inherent heterogeneity and irreversible damage is established. This study presents a data-driven based hierarchical multiscale combined finite-discrete element method (DHM-FDEM) for accurately reproducing rock macro-scale mechanical behavior while ensuring acceptable computational costs. To construct the DHM-FDEM scheme, firstly, upscale finite elements assembly (UFEA) and upscale crack elements assembly (UCEA) are constructed, incorporating meso-scale finite elements and crack elements with mechanical parameters directly derived from meso mechanics test results. Then, a conversion method is proposed to transform the mechanical response of UFEA and UCEA into a strain-stress pair of the macro-scale element, avoiding directly solving the mechanical state of macro-scale elements with mismatched mechanical parameters, thus ensuring the accurate reproduction of rock mechanical properties. Furthermore, UFEA and UCEA subjected to various loading paths are conducted by meso-scale FDEM to generate data sets comprising sequential strain-stress pairs with history dependence and one-to-many mapping relationships. The generated data sets are then applied to train a data-driven method, long short-term memory with mixture density network (LSTM-MDN), which directly maps strain input to stress output, thus replacing tedious and repetitive meso-scale FDEM computation on UFEA and UCEA to significantly save computational costs. Subsequently, UFEA and UCEA driven by LSTM-MDN are equivalent to macro-scale FDEM elements, replacing their phenomenological constitutive relationships and thereby achieving the multiscale numerical computation scheme. After that, the uniaxial compression test and Brazilian disk test are conducted to validate the computational accuracy and efficiency of DHM-FDEM. Finally, the capability of DHM-FDEM to accurately reproduce rock accumulated damage from loading-unloading cycles is verified through uniaxial and biaxial cyclic loading-unloading tests. [ABSTRACT FROM AUTHOR]

Understanding the micro-mechanism of brittle creep in saturated rocks and studying their mechanical behaviors after creep damage are of great significance to the design of rock engineering and the prediction of the long-term evolution of the Earth's crust. In this study, we first performed a series of uniaxial creep tests with different creep stage cut-offs on saturated intact sandstones. The brittle creep mechanism of the specimens was explored microscopically by analyzing P-wave velocity, acoustic emission (AE), and nuclear magnetic resonance (NMR) measurements. Then, specimens with different degrees of creep damage were subjected to a secondary short-term loading test or creep test, and their short- and long-term mechanical behaviors, together with AE monitoring, were systematically investigated. The experimental results show that (1) the anisotropy of the specimens increases significantly during creep, with the axial and lateral P-wave velocities exhibiting a difference of 30% at the onset of tertiary creep. (2) The tensile cracks dominate the transient creep stage and the early part of the steady creep stage, while the shear cracks dominate thereafter. (3) The porosities of the specimens increase with the loading stages, and the porosity increments corresponding to small pores are greater than those corresponding to large pores, for all creep stages. (4) Specimens with different degrees of creep damage show greater deformability, and their short-term and creep mechanical parameters, except for uniaxial strength, change dramatically. (5) The AE characteristics of creep-damaged specimens differ significantly from those of intact specimens, and the Kaiser stress memory effect was observed during reloading, with the memory stress being the previous creep stress. [ABSTRACT FROM AUTHOR]

The asymmetric wave equation encompasses the influence of the actual fine structure inside the medium on the wave field, which can better represent the complex seismic wavefield excited by the complex source and reflect the scale effects of the seismic wave response under equal computational power. However, when the finite-difference (FD) operator is applied to implement the numerical modelling using the asymmetric wave equation, numerical dispersion appears due to the use of difference operator to approximate the differential operator, which negatively affects the analysis of the seismic wavefield. To suppress the numerical dispersion, this paper proposes an improved Dung Beetle optimization (IDBO) algorithm to obtain the optimized FD operators. The IDBO algorithm adopts an improved Tent map and the opposition-based learning strategy to initialize the population, which improves the diversity of the population. The nonlinear function adaptive control strategy is introduced to adjust the population allocation ratio and boundary selection parameter R to achieve an adequate balance between global exploration and local exploitation. In addition, adaptive weights and the Levy flight mechanism are combined to improve the ball-rolling dung beetle position updating strategy to avoid falling into local extremes. Numerical dispersion analysis and numerical modelling results demonstrate that the optimization of FD operators based on the IDBO algorithm can effectively suppress numerical dispersion. It is of great significance to extract the wave field perturbation caused by heterogeneity due to the complex microstructure in the medium and analyse the influence of the microstructural properties in the medium on seismic wave propagation. [ABSTRACT FROM AUTHOR]

In this study, an enhanced numerical manifold method (NMM) simulator is developed to determine the combined impacts of reinforcement range and grouting timing on the effectiveness of grouting reinforcement for preventing the large deformation geo-hazard during the tunnel excavation through a fault rupture zone. To accomplish this objective, the limitations of the current two-dimensional simulation method, which lacks connection to the actual tunnel excavation process, are overcome by proposing a novel softening path function. Using this novel softening path function, each simulation step is given a specific physical meaning, establishing a connection to the actual tunnel excavation process. This improvement enables more accurate and analyzable simulation outcomes. To verify the accuracy of the proposed softening path function, a series of simulations of tunnel excavation are conducted using this softening path function. These results align closely with the results obtained by other reliable numerical methods and previous studies. After validation, several sets of numerical cases are conducted, considering 6 different geo-stress conditions, 10 different grouting reinforcement ranges, and 7 different grouting timings. Based on these simulation results, a critical value for reinforcement range, which equals to the diameter of tunnel face, is identified, and it is founded that delaying the grouting timing can increase the slurry migration range up to 94.6%. Furthermore, delaying the grouting timing can also reduce the convergence displacement of reinforced surrounding rocks after excavation up to 18.2% within a geo-stress range of 10 to 20 MPa. • A novel softening path function with clear physical meanings for tunnel excavation simulations is proposed. • A critical value of the grouting reinforcement range is identified. • Influences of grouting timing on the slurry migration range are revealed. • Influences of grouting timing on the convergence displacement of tunnels are revealed. [ABSTRACT FROM AUTHOR]

The determination of fundamental rock mechanical properties, uniaxial compression strength (UCS) and elastic modulus (E), constitutes a pivotal facet of rock engineering design. However, deriving these properties directly from standard laboratory tests on rock core samples can be challenging, especially when dealing with deep high-stress rock formations and weak fractured strata. Thus, it is crucial to establish a cost-effective and practical approach for predicting the macro-mechanical properties of rocks in situ. In this study, a machine learning approach was proposed to predict UCS and E by upscaling meso -mechanical parameters at particle scale in low-porosity crystalline rocks. To expand the correlation database of rock meso -macro mechanical properties, the meso -mechanical parameters, including the fracture toughness, tensile strength of the rock crystal interface, and the elastic modulus of rock crystal, were accurately measured, using a newly designed mechanical apparatus and a nanoindentation device. The grain-based models implemented in the combined finite discrete element method (FDEM-GBM) were developed based on these experimental results, and their reliability was validated though standard tests. Subsequently, a database, including 225 groups of data, was established using the numerical method. Five machine learning algorithms were applied to develop prediction models for UCS and E through data training in the database. Excellent performance improvement was achieved through the application of the grid-search method. The results indicate the optimized kernel ridge regression (KRR) and gaussian process regression (GPR) models demonstrated excellent performance with relative average errors of 4.9% and 1.1% in predicting UCS and E , respectively. Finally, the predicted values of UCS and E were compared with the experimental results, validating the feasibility of the optimized KRR and GPR models. [ABSTRACT FROM AUTHOR]

Understanding the micromechanical mechanism of the rock creep process is of great importance for studying the macroscopic time-dependent behavior of rocks. In this study, the evolution characteristics of the microstructure (cracks and pores) of saturated sandstones under short term and creep uniaxial compression conditions were investigated with the nuclear magnetic resonance (NMR) technique. The samples were first loaded to different stress levels and creep stages and then completely unloaded for NMR testing. Based on the testing results, the macroscopic deformation behavior, moisture migration law, pore size distribution, porosity, and microstructure change of the each sample under the short-term loading or different stages of creep were quantitatively analyzed. After that, by introducing a nonlinear elasto-viscoplastic damage creep model (EVP) by Zhao et al. (18:04017129, 2018), the relationships between the macroscopic irreversible strains and microscopic porosity increments were established. Overall, it was observed that: (1) regardless of the stress level, the magnitudes of the axial and lateral critical strains of samples at the onset of the accelerating creep stage are both relatively constant, and the axial strain is almost comparable to that at the peak stress in the short-term test, while the lateral strain is larger than that of the short-term test. (2) During the mechanical tests, the moisture in the samples migrates from large pores into small pores, and after mechanical tests, the porosities of the samples increase, in which the small pores always account for a larger proportion. (3) Corresponding to the three creep stages, the porosity of the sample increases slightly after the transient stage, increases to a constant value that is largely independent of stress after the steady stage, and increases significantly after the creep failure. In particular, compared to the initial porosity of 6.7%, the average porosities of samples taken to the onset of the tertiary stage and creep failure is 7.49% and 8.71%, increasing by 16.7% and 29.8%, respectively. (4) The porosity growth of sandstone during the brittle creep is mainly driven by the microscopic subcritical crack growth along the grain boundaries. [ABSTRACT FROM AUTHOR]

Post-processing is often inevitable for most additively manufactured components in order to improve material properties and product quality. In this study, the influence of post-heat treatments (PHTs) at 871 °C and 1177 °C on the microstructure and mechanical properties of a nickel-base Hastelloy C276 alloy prepared using wire arc additive manufacturing (WAAM) were investigated. The results showed that after a PHT at 871 °C, the as-built alloy was strengthened due to the formation of a large amount of Mo-rich nano-sized μ phase in the interdendritic areas. This was at the expense of a significant ductility loss. In contrast, no μ phase precipitates were observed after PHT at 1177 °C. Furthermore, the 1177 °C treatment led to the dissolution of the Mo-rich p phase which was present in the as-built sample, increased solid-solution strengthening, and improvements in both strength and ductility concurrently. This study enables an improved understanding of post-processing-microstructure-property inter-relationships for Hastelloy C276 alloy prepared by WAAM, providing guidelines for further microstructure optimization through PHT to improve the material's mechanical properties. • Hastelloy C276 using WAAM can be strengthened by post heat treatment (PHT). • PHT at 871 °C leads to the highest strength but lowest ductility due to intermetallics. • PHT at 1177 °C shows a combination of increased strength and lowered anisotropy. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease 2019 (COVID-19) has been declared a global pandemic. COVID-19 is more severe in people with diabetes. The identification of risk factors for predicting disease severity in COVID-19 patients with type 2 diabetes mellitus (T2DM) is urgently needed.Methods: Two hundred and thirty-six patients with COVID-19 were enrolled in our study. The patients were divided into 2 groups: COVID-19 patients with or without T2DM. The patients were further divided into four subgroups according to the severity of COVID-19 as follows: Subgroup A included moderate COVID-19 patients without diabetes, subgroup B included severe COVID-19 patients without diabetes, subgroup C included moderate COVID-19 patients with diabetes, and subgroup D included severe COVID-19 patients with diabetes. The clinical features and radiological assessments were collected and analyzed. We tracked the dynamic changes in laboratory parameters and clinical outcomes during the hospitalization period. Multivariate analysis was performed using logistic regression to analyze the risk factors that predict the severity of COVID-19 with T2DM.Results: Firstly, compared with the nondiabetic group, the COVID-19 with T2DM group had a higher erythrocyte sedimentation rate (ESR) and levels of C-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and procalcitonin (PCT) but lower lymphocyte counts and T lymphocyte subsets, including CD3+ T cells, CD8+ T cells, CD4+ T cells, CD16 + CD56 cells, and CD19+ cells. Secondly, compared with group A, group C had higher levels of Fasting blood glucose (FBG), IL-6, TNF-α, and neutrophils but lower lymphocyte, CD3+ T cell, CD8+ T cell, and CD4+ T cell counts. Similarly, group D had higher FBG, IL-6 and TNF-α levels and lower lymphocyte, CD3+ T cell, CD8+ T cell, and CD4+ T cell counts than group B. Thirdly, binary logistic regression analysis showed that HbA1c, IL-6, and lymphocyte count were risk factors for the severity of COVID-19 with T2DM. Importantly, COVID-19 patients with T2DM were more likely to worsen from moderate to severe COVID-19 than nondiabetic patients. Of note, lymphopenia and inflammatory responses remained more severe throughout hospitalization for COVID-19 patients with T2DM.Conclusion: Our data suggested that COVID-19 patients with T2DM are more likely to develop severe COVID-19 than those without T2DM and that hyperglycemia associated with the lymphopenia and inflammatory responses in COVID-19 patients with T2DM. [ABSTRACT FROM AUTHOR]

In this paper, we present a tetragonal cluster-based photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor with high wavelength sensitivity (WS). Indium tin oxide (ITO), as a dielectric material with adjustable photoelectric properties and low loss in the infrared range, is used in this sensor. The central rectangular air hole is used to construct an asymmetric structure which enables the sensor work in y and x polarization. We optimized the structural parameters of the sensor and the result shows that the sensor has high WS of 31,500 nm/RIU and 31,000 nm/RIU, wavelength resolution of 3.17 × 10−6 RIU and 3.23 × 10−6 RIU, maximum AS of 141.0 RIU−1 and 148 RIU−1, the refractive index (RI) detection range of 1.32–1.42 for y and x polarization, respectively. The sensor shows great potential in the detection of plasma, ethanol, and silicone oil. [ABSTRACT FROM AUTHOR]

• The internal curing effect generated form SC is investigated. • The evolution of UHPC pore structure and microstructures are observed. • The microstructure of UHPC containing SC is optimized. • The containing SC of UHPC is exhibited good mechanical properties. In this study, the effect of 5–30 % (by mass) of spent catalyst (SC) on the characteristics of ultra-high-performance concrete (UHPC) is investigated, including mechanical properties, volumetric stability, hydration kinetics, and microstructural development. Specifically, scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), and low-field proton nuclear magnetic resonance spectroscopy (1H NMR) are employed to clarify the microstructures, while thermogravimetric analysis (TG), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) are carried out to understand the phase variation. The results obtained show that the samples containing SC and additional water exhibit good mechanical properties, such as a 1.0 %-2.9 % higher compressive strength of UHPC with SC (5–15 %) and additional water compared to SC1 at 60 days. Additionally, SC can also improve the volumetric stability of UHPC. Moreover, the Ca/Si ratio of the hydration products decreases and the Al/Ca ratio increases with the enhancement of SC and additional water content. Furthermore, the water release effect of SC promotes the hydration of cement and pozzolanic reactions, leading to the generation of more hydration products and optimization of the pore structure and interfacial transition zone (ITZ) of UHPC in this study. [ABSTRACT FROM AUTHOR]

Granite for hosting the deep geological repository (DGR) is subjected to thermo-hydro-mechanical (THM) treatment for decades of years, while the variations in the tensile strengths of mineral grain interfaces (MGIs) with THM treatment are still unknown. Served as an important parameter in determining the macro mechanical properties of granite, quantifying the tensile strength degradation of MGI with THM treatment is crucial for ensuring the long-term safety of DGR. In this study, the varied tensile strengths of MGIs in the granite after different THM treatments were first directly measured based on a self-developed single-MGI mechanical test system. Three-bending tests were conducted on six-hundred MGIs, which were submitted to various THM treatments with a temperature of 25–175 °C and a pore pressure of 0–15 MPa. The tensile strengths of the interfaces of quartz, feldspar and the interfaces between quartz and feldspar were derived based on the Dugdale–Barenblatt (D–B) model. Results show that the average tensile strength of the interfaces of quartz is 1.06 times larger than that of interfaces between quartz and feldspar, and 1.13 times larger than that of the interfaces of feldspar. Besides, the tensile strength of MGIs seems more susceptible to the pore pressure than to the temperature, and the degradation of tensile strength is the most obvious in the interfaces between quartz and feldspar, followed by the interfaces of feldspar and finally the interfaces of quartz after THM treatments. Based on the characteristics of the tensile strength distributions of different MGIs after THM treatments, the tensile strength degradation models of MGIs related to THM treatments were proposed in meso scale. • The tensile strength of MGI in granite was directly measured via self-developed single-MGI mechanical test system. • The discrepancies in the tensile strength degradations of different MGIs in the THM-treated granites were distinguished. • Tensile strength degradation models related to THM treatment were proposed based on tensile strength distributions of MGIs. [ABSTRACT FROM AUTHOR]

Abstract: The selective laser melting (SLM) of the TiH2–Ti blended powder was performed in the present work. Porous titanium scaffolds characterized by high porosity (∼70%), interconnected Ti walls and open porous structures with macroscopic pores (in a range of ∼200 to ∼500μm) were successfully prepared at a laser power of 1000W and a scan speed of 0.02m/s. The effects of componential and processing conditions in terms of TiH2 content and scan speed on the microstructural development of porous titanium (porosity and pores size) were investigated. Reasonable mechanisms for pores formation during SLM apart from microstructural evolutions were proposed. [Copyright &y& Elsevier]

Two-dimensional layered materials have been widely utilized as nonlinear absorption materials to transfer continue-wave into pulse trains in fiber laser systems. Here, we prepare robust GaSe/GeSe composites with high power bearing capacity as saturable absorbers (SAs) and then investigate their nonlinear optical properties via broadband Z-scan measurement at 800 nm and 1550 nm, respectively. The modulation depths of GaSe/GeSe based SAs are measured to be 11.97% and 7.69% at 1550 nm. After incorporating the GaSe/GeSe SAs into an Erbium-doped fiber laser cavity, passively Q-switched pulse trains could be obtained with repetition rates changing from 83.58 to 136.78 kHz (70.41 to 161.65 kHz). The maximum output power and pulse energy are 52.1 mW/370.67 nJ (GaSe) and 21.6 mW/133.74 nJ (GeSe) under the maximum pump power of 600 mW. The results indicate that GaSe and GeSe possess outstanding thermal stability and could be employed as remarkable saturable absorption materials for high-energy pulses generation. [ABSTRACT FROM AUTHOR]

Background: This study evaluated the non-inferiority of bupropion extended-release (XL) compared to escitalopram for acute-phase treatment of Chinese patients with major depressive disorder (MDD).Methods: This randomized (1:1), double-blind, active-control study conducted between February 2015 and October 2016 included patients with MDD (DSM-IV) (N = 538). The treatment phase had three dose levels (level 1 [Week 1], level 2 [Week 2-4], and level 3 [Week 5-8]), which included either bupropion XL 150 mg, 300 mg, 300 mg or escitalopram 10 mg, 10 mg, 10-20 mg (once-daily), respectively. Primary outcome was mean change from baseline in Hamilton Depression Rating Scale-17 (HAMD-17) total score at Week 8.Results: Overall, 534 patients (bupropion XL, n = 266; escitalopram, n = 268) received at least one dose of study medication. The least square mean (standard error) change from baseline in HAMD-17 total score at Week 8 was -14.5 (0.41) in bupropion XL group and -15.4 (0.39) in escitalopram group (mean difference: 0.8 [-0.27, 1.94]). The response rate was 69.6% versus 72.9%, remission rate was 39.7% versus 47.2%, sustained response rate was 51.6% versus 56.3%, and sustained remission rate was 25.5% versus 28.6%, respectively, for bupropion XL versus escitalopram group. Adverse events were reported by 313 patients (bupropion XL, n = 157; escitalopram, n = 156); the most common on-treatment adverse event in both groups was nausea (10.5% versus 18.7%, respectively).Limitations: A non-inferiority short-term (8 weeks) study without a placebo arm.Conclusion: Results from this study demonstrated that the efficacy of bupropion XL was non-inferior to that of escitalopram in Chinese patients with MDD. [ABSTRACT FROM AUTHOR]

Spent fluidized catalytic cracking catalysts (SC) are considered toxic solid waste due to it is contained heavy metal ions, which can be polluting for the environment and harmful to humans. Since conventional disposal methods can be harmful to both the environment and people, therefore, new disposal methods need to be developed. In this study, 80 kg/m3 and 150 kg/m3 of SC are incorporated into the design of high-density cement-based materials (HDCM). The mechanical properties, hydration kinetics, durability, and environmental characteristics of HDCM containing SC are evaluated. The results shown that the HDCM has good mechanical properties, with a 6.62% increase in compressive strength at 28 days for HDCM containing 80 kg/m3 of SC. Furthermore, the HDCM containing SC has better long-term volumetric stability, with a 44.55% reduction in dry shrinkage compared to the reference. Further, the HDCM has a good immobilizing ability for heavy metal ions. The leaching concentrations of Ni and V from C1 are only 0.203 mg/L and 0.282 mg/L, and the immobilizing rate is 99.08% and 98.26%, respectively. For the C2, the leaching concentrations of Ni and V are 0.198 mg/L and 0.402 mg/L, the immobilizing rate is 99.31% and 98.25%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficiency of five curing regimes have been compared. • Curing condition has significant effect on mechanical property development. • Reaction of SCM greatly rely on curing conditions. • The curing condition has great influence on the microstructure formation. In this study, the mechanical property and microstructure development of UHPC (ultra-high performance concrete) incorporating different PS (phosphorous slag) content is studied under five curing regimes. The microstructure of UHPC is also discussed by TG, XRD, MIP, the SEM-EDS and 29Si NMR. The result indicated that the high strength of UHPC containing PS is obtained by heat curing in a short time (e.g. The compressive strength of PS60 is 135.5 MPa and 134.4 MPa under curing conditions of 90 °C (48 h) and 1 MPa (6 h), respectively). The cement is completely hydrated, and the hydrated product of calcium hydroxide is completely consumed in UHPC that contains a lot of PS under the heating curing (90 °C, 1 MPa-180 °C and 2 MPa-250 °C) by the result of TG combined with XRD. In addition, the hydration products are tobermorite and xonotlite under high temperature and high pressure curing conditions. [ABSTRACT FROM AUTHOR]

For the problems of seismic wave propagation, scale effects will appear while considering the microstructures of medium. Scale effects mean that new components of wave fields appear in the seismograms due to the microstructure interactions in the medium and vary with the change of the characteristic length scale parameters. The generalized continuum mechanics (GCM) theory which introduces the intrinsic length scales of the microstructures is suitable for analyzing the scale effects of seismic wave propagation. We adopt the concept of multi-scale microstructure interactions, that is, the modified couple stress theory, and the one-parameter second strain gradient theory, as two branches of the GCM theory, have the same definition characteristic length scale parameters of medium, to describe the microstructure interactions at different scales. Through the quantitative relationship between the characteristic length scale parameters of the medium and the micropore, the layered model of the characteristic length scale parameters of the micropore is constructed for numerical modeling in a unified framework, and the scale effects of seismic wave propagation is analyzed. More specifically, the asymmetric elastic wave equations under a unified framework are derived, and the physical definition of the characteristic length scale parameters of medium is given. And the influence of the characteristic length scale parameter of the micropore on the seismic wave propagation is focused on. Finally, the scale effects of seismic waves excited by high-speed trains under the viaduct system are analyzed, and some conclusions are drawn. • The influence of microstructures on seismic wave propagation needs to be considered. • The GCM theory containing scale parameters is suitable for analyzing scale effects. • The interface information of the scale parameter can be reflected in seismic records. [ABSTRACT FROM AUTHOR]

The approach of dynamical system (DS) is promising for modeling robot motion, and provides a flexible means of realizing robot learning and control. Accuracy, stability, and learning speed are the three main factors to be considered when learning robot movements from human demonstrations with DS. Some approaches yield stable dynamical systems, but these may result in a poor reproduction performance, while some approaches yield good reproduction performance but are quite complex and time-consuming. In this paper, we address the accuracy-stability-speed issues simultaneously. We present a learning method named the fast and stable modeling for dynamical systems, which is based on the extreme learning machine to efficiently and accurately learn the parameters of the DS as well as to ensure the asymptotic stability at the target. We confirm the proposed approach by performing both 2-D tasks of learning handwriting motions and a set of robot experiments. [ABSTRACT FROM AUTHOR]

In this paper, we experimentally perform the measurement of the backscattered light intensity from the underwater targets with different size. We develop a simple system, which can easily measure the intensity of the backscattered light, after the laser is scattered at the target underwater. We find that, the signal period is related to the particle size, and the stability of the intensity (standard deviation) varies linearly with changing the particle size. After the calibration, our system can be used to precisely determine the particle size of arbitrary targets. Our method could open a new opportunity for the future underwater detection using femtosecond pulse laser. [ABSTRACT FROM AUTHOR]

Abstract Background Despite evidence from toxicological studies describing the potential neurotoxicity of perfluoroalkyl substances (PFAS), their role in neurodevelopment remains uncertain amid inconsistent findings from epidemiological studies. Methods Using data from 218 mother-child dyads from the Health Outcomes and Measures of the Environment Study, we examined prenatal and childhood (3 and 8 years) serum concentrations of four PFAS and inattention, impulsivity, and visual spatial abilities. At 8 years, we used the Conners' Continuous Performance Test-II to assess attention and impulse control and the Virtual Morris Water Maze (VMWM) to measure visual spatial abilities. Results In multiple informant models, there was no evidence to indicate that prenatal or childhood PFAS are associated with attention. However, there was an inverse association between prenatal ln-perfluorooctanoate (PFOA) and errors of commission (β = −2.0, 95% Confidence Interval [CI] −3.8, −0.3). Ln-perfluorononanoate (PFNA) at 3 years was associated with longer (poorer) VMWM completion times of 3.6 seconds (CI 1.6, 5.6). However, higher concurrent concentrations of ln-perfluorohexane sulfonate (PFHxS) (β = −2.4 s, 95% CI −4.4, −0.3) were associated with shorter (better) times. Higher prenatal PFHxS was positively associated with percentage of traveling distance in the correct quadrant (β = 4.2%, 95% CI 0.8, 7.7), indicating better performance. Conclusion Findings were mixed for prenatal and childhood PFAS concentrations and visual spatial abilities. There is not enough evidence to support that PFAS are associated with visual spatial abilities as assessed by the VMWM or CPT-II measures of inattention or impulsivity in children at age 8 years. Highlights • Prenatal and childhood PFAS are not associated with CPT-II measures of inattention at 8 years. • Inconsistent associations were noted between PFNA and PFHxS with VMWM performance at 8 years. • Findings do not support associations between PFAS and VMWM measures of visual spatial abilities. [ABSTRACT FROM AUTHOR]

Medical imaging plays an indispensable role in clinical diagnosis and assessment of pathophysiological correlations in dermatology. However, the existing imaging techniques are limited to resolve the concentration and spatial distribution of skin melanin for chromatodermatosis. In this work, we developed a fast linear confocal scanning photoacoustic dermoscopy (FLCS-PAD) for label-freely visualizing the pathologic structures of pigmented lesion and quantitatively evaluating melanin content of pigmented abnormality. The FLCS-PAD was utilized for non-invasive and high-resolution imaging of epidermal conditions in Cafe-au-lait macules patients. Image results demonstrated that there was a significant difference between normal and Cafe-au-lait macules skin (p < 0.05). By implementing a fast linear confocal scanning mode, an individual's photoacoustic pathological section can be quickly obtained with clinical score in ∼1 s. The FLCS-PAD might as well extend to diagnose other dermatological conditions, which opens a perspective in dermatological imaging technology. [ABSTRACT FROM AUTHOR]

Energy storage is crucial for both smart grids and renewable energy sources such as wind or solar, which are intermittent in nature. Compared to electrochemical batteries, flywheel energy storage systems (ESSs) offer many unique benefits such as low environmental impact, high power quality, and larger life cycles. This paper presents a novel utility-scale flywheel ESS that features a shaftless, hubless flywheel. The unique shaftless design gives it the potential of doubled energy density and a compact form factor. Its energy and power capacities are 100 kWh and 100 kW, respectively. The flywheel is made of high-strength steel, which makes it much easier to manufacture, assemble, and recycle. Steels also cost much less than composite materials. Design and analysis of the shaftless flywheel are presented first. In addition, the system incorporates a new combination active magnetic bearing. Its working principle and levitation control for the flywheel are discussed. The design of an integrated coreless permanent-magnet (PM) motor/generator for the flywheel is given as well. Initial test results show that the magnetic bearing provides stable levitation for the 5443-kg flywheel with small current consumption. [ABSTRACT FROM PUBLISHER]

Fe 3 Al based iron aluminide has continuously been attractive because of its excellent oxidation resistance, corrosion resistance, light weight and low material cost. It has been considered as a promising replacement of regular stainless steel in fossil energy industry. However, the industrial application of iron aluminide is limited by its low room temperature ductility and high fabrication cost. In recent years, additive manufacturing processes have been proved capable of producing iron aluminide with relatively lower cost as compared to traditional powder metallurgy processing. In the present research, the influence of thermal cycling during the additive manufacturing of Fe 3 Al based iron aluminide on the phase fraction inside the deposited material has been simulated and investigated using in-situ neutron diffraction. Upon heating, the Fe 3 Al based iron aluminide has experienced Fe 3 Al↔FeAl phase transformations, FeAl phase ordering-disordering, and Fe 3 Al phase transformation from imperfectly ordered B2 structured to perfectly ordered D0 3 structure. Also, the existence of the forbidden Fe 3 Al 110 reflection has been determined by neutron diffraction and further evaluated. In addition, the variation of phase fractions throughout the heat treatment has been quantitatively analyzed by Rietveld refinement. [ABSTRACT FROM AUTHOR]

Understanding the electrochemical reaction mechanisms and kinetics in batteries is the key challenge for developing breakthroughs with new or existing electrode materials. X-rays and neutrons are excellent probes for studying atomic structure changes and phase evolution in battery materials during charge and discharge. Synchrotron X-ray powder diffraction (SXPD), with its high angular resolution and beam intensity, allows fast scattering and diffraction data collection to record crystalline structure changes that occur on short time-scales. Neutron powder diffraction (NPD) provides complementary information that is sensitive to different structural details during charge/discharge. More recently X-ray absorption spectroscopy (XAS) has been used to identify the oxidation states of transition metal ions present in new cathode compositions at different stages of battery cycling. Using in-house designed battery cells, electrodes or other cell components can be subjected to conditions designed to mimic their real operating conditions. It is preferable to investigate battery materials in operation to identify any critical intermediate stages during charge/discharge rather than using ex situ methods to analyse dismantled batteries. Examples and combinations of SXPD, XAS, and NPD measurements, which have been used to investigate lithium ion batteries and sodium ion batteries, are described and reviewed in this contribution. [ABSTRACT FROM AUTHOR]

In this paper, the effect of phosphorus slag(PS)hydration kinetics and microstructural development of UHPC with different degree of substitute (20%, 40% and 60% by mass) were explored. Up to 60% substitution of cement by PS which still shown excellent mechanical property compared to without PS at the age of 60-days. The phase development is a qualitative discussion by thermal gravimetric analysis combined with XRD with Rietveld method, the pore structure is evaluated to MIP. The hydration products are characterized by SEM (scanning electron microscopy) with EDS (Energy-dispersive X-ray) analyses. The results shown that the utilization rate of cement has been significantly improved, for instance, the hydration rate of the cement is enhanced from 54.3% for PS0 to 87.0% for the UHPC with PS60; the Ca/Si ratio decreased with the enhance of PS content and the microstructure is become denser by SEM-EDS tests. The pozzolanic-reaction of PS cloud produce more hydrated products by thermodynamic calculation, which can optimize the pore structure of paste. And the growth trend of C–S–H gel is consistent with the compressive strength growth trend. [ABSTRACT FROM AUTHOR]

The near-β Ti-55531 (Ti-5Al-5Mo-5V-3Cr-1Zr, wt%) alloy with thin-wall structures were manufactured by laser melting deposition (LMD), and followed by the post-processing of electroshocking treatment (EST). The microstructure evolution before and after EST were characterized via using the scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The results showed that the microstructure of as-deposited specimen was mainly composed of short columnar grains and equiaxed grains, showing a unique structure of alternating short columnar grains-equiaxed grains-short columnar grains. The results of EBSD showed that EST could reduce the orientation concentration and weaken the texture of β phase. XRD results indicated that the α phase content slightly increased after EST. The micro-strain and lattice constant of β phase were changed after EST, which were probably ascribed to the precipitation of α, the generation of crystal defects on α/β interface, and the decrease of texture intensity. The results of mechanical properties indicated that EST could increase the microhardness, the yield strength and the tensile strength, which were due to the variation of microstructure. All results show that EST is an effective approach for optimizing the microstructure and improving the mechanical properties of LMD near-β titanium alloy. [Display omitted] • LMD Ti-55531 shows a unique structure of alternating columnar-equiaxed-columnar grains. • EST can alleviate the orientation concentration and weaken the texture of β phase. • More α tends to precipitate inside β after EST, due to the thermal and athermal effects of EST. • Variation of micro-strain and lattice constant are ascribed to the precipitation of α and decrease of texture intensity. • EST can optimize microstructure and improve mechanical properties of LMD near-β titanium alloy. [ABSTRACT FROM AUTHOR]

• The nanodroplet is always in not-cloaking state on the LISs of copper nanopillar substrate, even with a thick lubricant. • The droplet changes from the Cassie state to the partial Wenzel state under the influence of the electric field. • The coating film thickness increases with the electric field, the nanodroplet changes to a cloaking state. • Compared to the LISs of silicon substrate, the electro-stretching effect is easier to occur on the LISs of copper substrate. • The reduction of ACG increases with the lubricant thickness under parallel E , while has a maximum under perpendicular E. Due to the block of the lubricant on liquid-infused surfaces (LISs), the molecular processes near the liquid-liquid interface and the shape of droplet under electrowetting actuation are still difficult to observe with simple optical methods. Molecular dynamics (MD) simulation provides a visual method for observing the nanodroplet morphology on the LISs. In this paper, the impacts of the substrate characteristics and the lubricant thickness on the cloaking state, the wetting state and the diffusion diameter of nanodroplet were studied by the MD simulation. It is found the coating film of the nanodroplet increases with the lubricant layer thickness on the LISs of silicon nanopillar substrate, while the nanodroplet is always in the not cloaking state on the LISs of copper nanopillar substrate, even with a very thick lubricant layer. Subsequently, the electrowetting behaviors of the nanodroplet under the external electric field in the parallel and perpendicular directions to the surface were studied. The results indicate the droplet changes from the Cassie state to the partial Wenzel state under the influence of the external electric field on the LISs of both substrates. Meanwhile, the coating film thickness increases with the electric field intensity, the nanodroplet changes from a not cloaking state to a cloaking state on the LISs of copper substrate, while still is in a not cloaking state on the LISs of silicon substrate. Compared to the LISs of the silicon substrate, the electro-stretching is easier to happen on the LISs of the copper substrate. Finally, the impact of lubricant layer thickness on the nanodroplet electrowetting was studied on both copper and silicon substrates. It is found the reduction of nanodroplet apparent contact angle increases with the lubricant layer thickness under an external parallel electric field, while it has a maximum on the moderate lubricant thickness under an external electric field in a perpendicular upward or downward direction. Our results indicate the droplet deformation on LISs under the external electric field is contributed to the competition of the electrowetting, the electro-stretching, and the pinning effect. [ABSTRACT FROM AUTHOR]

Optical thermometry in the second near-infrared (NIR-II) window with high tissue penetration depth has great value in biological and medical sciences. Herein, we reported the synthesis of ZrO 2 : Er3+/Yb3+/Ho3+ nanocrystals for temperature sensing in both NIR-II and visible regions. The effects of Ho3+ co-doping concentration on the structure, morphology, photoluminescence properties and temperature sensing behaviors of ZrO 2 : Er3+/Yb3+/Ho3+ were investigated in detail. X-ray diffraction and scanning electron microscopy measurements validated that the introduction of Ho3+ ions could induce the phase transition of ZrO 2 from monoclinic to tetragonal phase and increase the crystalline grain size of the samples. Upon 980 nm excitation, the enhancements in both visible and near-infrared emissions were achieved via the addition of 0.05 mol%Ho3+. Meanwhile, the optical thermometry performances of the samples were found to depend on the Ho3+ concentration, when the luminescence intensity ratio of I 525 /I 541 (LIR-1) and also that of I 1463 /I 1224 (LIR-2) were selected for temperature sensing. For LIR-2, the maximal relative sensing sensitivity (S r) of 2.08%K−1 was obtained for the 1%Ho3+ co-doped sample at 303 K, which was higher than many other phosphors operating in the NIR-II window. The present work may provide an effective route to develop efficient visible and NIR luminescence materials for high-performance temperature sensing. • Ho3+ concentration affected structure and optical properties of ZrO 2 : Er3+/Yb3+. • The addition of 0.05 mol% Ho3+ enhanced the UC and NIR luminescence. • Optimal relative sensitivity was 2.08%K−1 based on LIRs between 1463 and 1224 nm. [ABSTRACT FROM AUTHOR]