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The defects on raceways would aggravate the vibration of bearing and greatly influence the bearing performance, in order to monitor the running state of the bearing and detect the early defect, the characteristics induced by the defect must be explored. This paper establishes a bearing dynamic model to explore the effect of raceway defects on the nonlinear dynamic behavior of rolling element bearing. The interaction between ball and races is modeled based on Hertz theory, while the presence of defects changes the ball-race interaction. The effects of defect size, position and number on bearing dynamic behaviors are investigated with the aid of phase trajectories, shaft center orbits, FFT spectra, etc. The results indicate that the defects can make the motion of the system more complicated and induce vibration at some characteristic frequencies, which can be used to recognize the bearing failure at early stage. The proposed research provides useful information for the design and status monitoring of mechanical systems.

Photocatalytic hydroxy group transformation to carbonyl is an important application in organic chemistry. It seems challenging to acquire great selectivity toward carbonyl products in green water solution, especially for the wide-bandgap semiconductors which always need to seek assistance from organic media like acetonitrile. Herein, we cast off the dependence on such organic solvents and develop an efficient NixSy modification on ZnS nanorods, for selective oxidation of benzyl alcohols coupled with H2 evolution in anaerobic water. The ternary augmentation in H2 production, alcohol conversion, and, more strikingly, benzaldehyde selectivity (from 8.1% to 90.5%) was simultaneously achieved by loading NixSy cocatalysts. Mechanism investigations indicated a striking transformation from hole-predominant oxidation on ZnS surface to an electron-initiating dehydrogenation of alcohols on NixSy nanoparticles. Besides, NixSy nanoparticles tend to swiftly desorb the produced benzaldehyde, thereby resulting in promote...

Previous theoretical studies have found that the concentration variations within a certain range have a prominent effect on inter-mineral equilibrium isotope fractionation (103lnα). Based on the density functional theory, we investigated how the average Ca–O bond length and the reduced partition function ratios (103lnβ) and 103lnα of 44Ca/40Ca in forsterite (Fo) are affected by its Ca concentration. Our results show that Ca–O bond length in forsterite ranges from 2.327 to 2.267 A with the Ca/(Ca + Mg) varying between a narrow range limited by an upper limit of 1/8 and a lower limit of 1/64. However, outside this narrow range, i.e., Ca/(Ca + Mg) is lower than 1/64 or higher than 1/8, Ca–O bond length becomes insensitive to Ca concentration and maintains to be a constant. Because the 103lnβ is negatively correlated with Ca–O bond length, the 103lnβ significantly increases with decreasing Ca/(Ca + Mg) when 1/64 orthopyroxene > clinopyroxene > calcite ≈ diopside > dolomite > aragonite. Olivine and pyroxenes are enriched in heavier Ca isotope compared to carbonates. The 103lnα between forsterite with a Ca/(Ca + Mg) of 1/64 and clinopyroxene (Ca/Mg = 1/1, i.e., diopside) is up to ~ 0.64‰ at 1200 K. The large 103lnαFo-diopside relative to the current analytical precision for Ca isotope measurements suggests that the dependence of 103lnαFo-diopside on temperature can be used as a thermometer, similar to the one based on the 103lnα of 44Ca/40Ca between orthopyroxene and diopside. These two Ca isotope thermometers both have a precision approximate to that of elemental thermometers and provide independent constraints on temperature.

We present a new processing & analysis package of the atomic pair distribution function (PDF) for the electron diffraction (ED) pattern based on the total scattering theory which has been broadly used in the X-ray or neutron diffraction to reveal the local atomic structures, but PDF analysis based on the electron diffraction is still rarely used for the lack of an efficient PDF tool. The program was written as a package of DigitalMicrograph, a very popular software to record and analyze the data of transmission electron microscopes (TEM) in the most of TEM laboratories. The azimuthal rotation-average projection algorithm was implemented to enhance the signal-noise ratio of the intensity profile. In order to obtain the reduced structure function, the cubic spline fitting method was utilized to subtract the background scattering. The real-time displayed PDF makes data normalization easier and more accurate, and results of coordination numbers and averaged bond angles can be extracted from calibrated PDFs in real time. Program summary Program Title: ePDF tools Program Files doi: http://dx.doi.org/10.17632/ff94wp42wd.1 Licensing provisions: GPLv3 Programming language: DigitalMicrograph scripting language Nature of problem: The total scattering technique has been widely used in X-ray or neutron diffraction, but for the electron diffraction it still lacks an efficient analysis tool for the atomic pair distribution function. Solution method: Intensity profile is obtained by azimuthal rotation-average projection of 2D SAED pattern, the background scattering is subtracted by the cubic spline method, data normalization is real-time performed based on the total scattering theory, the atomic pair distribution functions obtained by Fourier transform will be used to quantitative analysis.

Photocatalytic CO2 reduction is a promising strategy to address environmental and energy issues that are vexing the modern society. However, the efficiency of CO2 photoreduction into fuels such as methane (CH4) is substantially restricted by high CO2 activation barrier and inefficient proton supply. Here, Mo-doped WO3·0.33H2O nanorods have been synthesized and Mo doping in WO3·0.33H2O dramatically increased the CH4 production yield by 5.2 times from 1.02 to 5.3 μmol gcat−1 h−1 under water vapor without the assistant of any sacrificial agent or noble metal. The Mo doping proves capable of facilitating CO2 activation by improving the ability to store and localize photogenerated electrons and boosting the transfer of photoexcited electrons to adsorbed CO2. In addition, proton and electron insertion converts WO3·0.33H2O into tungsten bronze (HxWO3·0.33H2O) under light irradiation, guaranteeing required electrons and protons for CO2 reduction. The enhanced water oxidation of Mo-doped WO3·0.33H2O promotes proton supply and insertion process, improving the hydrogenation process of the carbon intermediate to generate CH4. The combined action of the enhanced CO2 activation and water oxidation with efficient proton and electron insertion improves the performance of CO2 photoreduction to CH4. This work might help to shed light on deeper insights into the design of CO2 photoreduction catalysts.

Equilibrium Mg isotope fractionation properties between aqueous Mg2+ and minerals are the key for the applications of Mg isotopes in geochemistry. This study conducts first-principles molecular dynamics (FPMD) simulations for aqueous Mg2+ based on the density functional theory (DFT). Thirty-five snapshots are extracted from the FPMD trajectories after equilibration for the calculations of the reduced partition function ratio (β factor or 103lnβ). Combining with the β factors of minerals, we found that the β factor decreases in the sequence of lizardite > brucite > aqueous Mg2+ > dolomite > magnesite > calcite > aragonite. Our calculations also confirm the effect of Mg concentration on the β factor of calcite, and further show that the concentration effect is negligible when Mg/(Mg + Ca) (atomic ratio hereafter) is lower than 1/32. Our results depict significant equilibrium Mg isotope fractionations between minerals and aqueous Mg2+ (103lnαminerals-Mg_aq), which are dominantly controlled by the average force constant of Mg in these phases. Compared to aqueous Mg2+, carbonates are enriched in light Mg isotopes but brucite and lizardite show enrichment in heavy Mg isotopes. Among all minerals, 103lnαaragonite-Mg_aq is the largest, which is up to −14‰ at 300 K. Notably, 103lnαcalcite-Mg_aq is not only controlled by temperature, but also significantly affected by Mg content in calcite. 103lnαcalcite-Mg_aq is negatively correlated with Mg content in calcite. The experimentally measured Mg isotope fractionations between minerals (dolomite, magnesite, brucite) and solution at equilibrium are consistent with our predicted results, showing the accurate description of FPMD simulations for aqueous Mg2+ and the reliability of our calculations. Overall, the calculated equilibrium Mg isotope fractionations between minerals and aqueous Mg2+ provide a guideline for applications of Mg isotopes in aqueous geochemical processes.

Synthesis of intermediates and fine chemicals for the selective oxidation of alcohols to corresponding aldehydes and carboxylic acid is an extremely significant chemical reaction. Herein, a binary W18O49/holey ultrathin g-C3N4 nanosheets (HU-CNS) nanocomposite was prepared via a solvothermal method and it exhibited excellent photocatalytic activity for the selective oxidation of benzyl alcohol in an aqueous medium under room temperature and atmospheric pressure. The as-synthesized W18O49/HU-CNS composites showed higher selectivity and conversion efficiency compared to pure g-C3N4, which was mainly ascribed to the moderate adsorption capacity of benzaldehyde on the composite. The high conversion originates primarily from the following: (1) the W18O49/HU-CNS nanocomposite possessing a stronger ability to chemisorb alcohol than g-C3N4; (2) the oxygen vacancies on W18O49 nanowires not only supplied active centers for the activation of O2 to O2•– but also extended the range of light response from the visible t...

Calcium is a major element of the Earth, the Moon, terrestrial planets, and rocky meteorites. Here we present equilibrium Ca isotope fractionation factors of Ca-bearing minerals using the first-principles calculations based on density functional theory (DFT). The sequence of minerals from the isotopically heaviest to the lightest in Ca is forsterite > orthopyroxene (opx) > grossular ∼ pigeonite > diopside > anorthite > oldhamite. Overall, the equilibrium fractionation of Ca isotopes is mainly controlled by the average bond lengths. Although oldhamite is enriched in light Ca isotopes relative to silicate minerals in equilibrium, natural oldhamite of enstatite chondrites are isotopically heavier than coexisting silicate materials. This implies that enstatite chondrites oldhamites should have been formed during solar nebular gas condensation instead than during parent body processing. Following previous models for crystallization of the Lunar Magma Ocean (LMO), we simulated Ca isotopic fractionation of the LMO based on our calculated equilibrium Ca isotope fractionation factors. It shows that the δ 44 / 40 Ca of the lunar anorthositic crust should be lower than the average of the bulk Moon by 0.09–0.11‰. Considering that the lunar mantle might have overturned and mixed after solidification of the LMO, we further predict that the lunar mantle should be isotopically heavier than the bulk Moon by 0.17–0.26‰ if the mantle was fully overturned, or only by 0.06–0.08‰ for the case of fully mixing. Therefore, we predict that the potential offset of Ca isotopic composition between the anorthositic crust and the lunar mantle can be used to test LMO evolution models.

In this study, we show that the poor visible light photoelectrochemical (PEC) and photocatalytic activities of both wide-bandgap TiO2 and small-bandgap Bi2WO6 photocatalysts can be remarkably enhanced by constructing hierarchical Bi2WO6 nanosheet-wrapped TiO2 nanorod arrays (NRAs). X-ray photoelectron spectroscopy (XPS) measurements give direct experimental evidence for the establishment of a type II band alignment, which realizes visible light PEC performance of heterogeneous architecture through the transfer of photoexcited electrons from Bi2WO6 to TiO2. Moreover, Au nanoparticles (NPs) grown on the hierarchical Bi2WO6 nanosheets of TiO2/Bi2WO6 NRAs drastically enhance visible light PEC and photocatalytic activity of heterogeneous architectures because of surface plasmon resonance (SPR) effect. Benefiting from the synergistic effect of the type II band alignment and SPR effect, the hierarchical TiO2/Bi2WO6/Au NRAs achieve a photocurrent density of 29 μA cm−2, 11 times higher than that of TiO2 NRAs and 2.6 times as high as that of hierarchical TiO2/Bi2WO6 NRAs at 1 V vs Ag/AgCl. The hierarchical TiO2/Bi2WO6/Au NRAs exhibit remarkable stability in 2 h of light illumination. Additionally, the hierarchical TiO2/Bi2WO6/Au architectures show a significantly enhanced photocatalytic degradation for methyl blue (MB) molecules with a photodegradation of 91.5%. The study sheds new light on constructing visible light photocatalyst by forming the type II band alignment and integrating SPR effect.

A layered oil slip model considering the slip and thermal effect is proposed to explore the mechanism of film thickness behaviours at high speed. The modified Reynolds equation considering the interfacial slip is derived and the limiting shear stress of lubricant is utilised as the criteria for the occurrence of slip. The film thickness obtained from the proposed model matches the experimental results very well. The results indicate that both the interfacial slip and thermal effect contribute to the behaviours of film thickness at high speed. The interfacial slip may occur at both fast or/and slow surfaces depending on the speed conditions.

Solar CO2 photoreduction into hydrocarbons is promising and significative. However, many conventional catalysts reported usually suffer from poor photocatalytic activities. Herein, ultrathin Bi2WO6 nanosheets with a thickness of about 4.8 nm have been synthesized by hydrothermal method, which exhibited a CH4 production rate of 19 ppm g−1 h−1 under a low CO2 concentration of 400 ppm. PtOx nanoparticles with a size of about 2 nm were then loaded on the Bi2WO6 nanosheets as excellent co-catalysts by photoreduction in aqueous solution, and an optimal CH4 yield of 108.8 ppm g−1 h−1 was achieved, which was about 5.7 times than that of pristine Bi2WO6 nanosheets. Further analyses of photocurrent curves, electrochemical impedance spectroscopy and polarization curves of water oxidation indicated that the improved photocatalytic activity was suggested to result from the enhanced carrier separation and accelerated water oxidation by PtOx nanoparticles. The work will likely give a deeper insight of PtOx nanoparticles and provide a new idea to design catalysts for CO2 photoreduction to CH4.

The Zn-based metal-organic framework (MOF) catalysts MOF-74, Au@Pd@MOF-74, Pt/MOF-74, and Pt/Au@Pd@MOF-74, were assembled. Core-shell Au@Pd, in which Au nanoparticles (NPs) serve as the core for the epitaxial growth of Pd shells, was encapsulated into MOF-74 nanoshuttles to control the MOF-74 morphology and impart NP functionality. Pt NPs were loaded onto the MOF-74 surface. Pt/MOF-74 catalyzed CO2 conversion at 99.7% CO selectivity in the reverse water-gas shift (RWGS) reaction, and Au@Pd@MOF-74 photocatalyzed CO2 with 100% CO selectivity. Importantly, the catalyst Pt/Au@Pd@MOF-74, not only catalyzed the conversion of CO2 to CO in RWGS with 99.6% selectivity, but also photocatalyzed CO2 to CH4 at low concentration (800 ppm).

In this study, we show for the first time a hierarchical ZnO/ZnFe2O4 nanotube array photoanode for water splitting to produce hydrogen. In this photoanode, the wrinkle-like ZnFe2O4 nanosheets (NSs) are grown onto ZnO nanotube arrays through adsorption and annealing reaction. The hierarchical ZnO/ZnFe2O4 nanotube array photoanode exhibits outstanding PEC water splitting to produce hydrogen due to the remarkable visible-light harvesting ability and the large surface area of wrinkle-like ZnFe2O4 NSs. Under simulated solar light irradiation, the hierarchical ZnO/ZnFe2O4 nanotube arrays (NTAs) achieve a remarkably enhanced photocurrent density of 1.3 mA/cm2, which is 2.2-fold higher than that of pristine ZnO NTAs at 0 V vs Ag/AgCl. Moreover, the hydrogen production rate of the hierarchical ZnO/ZnFe2O4 nanotube array photoanode is 3.6-fold higher than that of pristine ZnO nanotube array photoelectrode at 0.6 V vs Ag/AgCl.

The K concentration effects on K-O bond length and the reduced partition function ratios of 41K/39K in alkali feldspars have been explored using the density functional theory (DFT) method. In alkali feldspars, the average K-O bond length increases with increasing K content, measured as K/(K + Na) molar ratio, ranging from 2.724 A in alkali feldspar with a K/(K + Na) of 1/16 to 2.880 A in microcline (K/(K + Na) = 1). Our results show large K concentration effect on the calculated reduced partition function ratio. For example, 10 3 ln 41 K / 39 K α feldspar - microcline between alkali feldspar with a K/(K + Na) of 1/16 and microcline are 2.21‰ at 300 K and 0.42‰ at 700 K, which are comparable to the 41K/39K variation observed in natural samples. Furthermore, isotope fractionation, 10 3 ln 41 K / 39 K α feldspar - microcline , is negatively linearly correlated with the average K-O bond length in alkali feldspars. Therefore, the concentration effect on K isotope fractionations needs to be considered in the applications of K isotopes in the fields of geochemistry and cosmochemistry, such as the formation of the lunar anorthositic crust and the evolution of the Earth’s crust.

Photocatalysis arises as a green, sustainable approach to conventional industrial catalysis for the synthesis of valuable organic chemicals from biomass. However, photoinduced holes and/or reactive oxygen species are usually fatal to the selective redox process, and are responsible for inducing undesirable side reactions especially in the presence of water. Herein, we demonstrate a cascade strategy of photocatalytic oxidation/hydrogenation that could manage the efficient conversion (99%) of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) with high selectivity (∼99%). The first reaction is conducted under UV irradiation, with the amorphous TiO2 surface storing the photoinduced electrons, and the protons extracted from alcohol via photooxidation. On subsequently switching to the dark, the stored H+/e− pairs undergo proton-coupled electron transfer (PCET) and contribute to the selective hydrogenation of HMF. This route effectively mitigates the negative impact of H2O and active species on the product selectivity. The oriented adsorption for the aldehyde group of HMF as well as the promoted product desorption bring about the high selectivity of BHMF over amorphous TiO2. The cascade catalytic pathway based on the stored H+/e− provides a reliable approach for biomass functionalization.

Applications of single-phase TiO2 and ZnO in the field of photoelectrochemical (PEC) solar hydrogen generation are limited by their high recombination rate of photogenerated charge carriers. Herein, a novel three-dimensional (3D) architecture comprising two-dimensional (2D) ZnO nanosheets (NSs) coated onto one-dimensional (1D) TiO2 nanowire arrays (NWAs) (ZnO/TiO2 2D/1D NSs-NWAs) is designed as an efficient photoelectrode for PEC solar hydrogen production. A type II band alignment established in the photoanode enables the electrons to be efficiently transported from ZnO NSs to TiO2 NWAs and the holes to be transferred from TiO2 NWAs to ZnO NSs, efficiently suppressing the recombination of electrons and holes. Additionally, the 3D architecture offers large areas for harvesting light energy, large interfacial contact areas with the electrolyte, and more pathways for rapid transfer and separation of charge carriers. The ZnO/TiO2 2D/1D NS-NWA photoanode exhibits remarkable enhancement for hydrogen generation in a neutral electrolyte solution. The H2 generation rate of the ZnO/TiO2 2D/1D NS-NWA photoanode is 3-fold that of the bare TiO2 NWA photoanode. Moreover, the ZnO/TiO2 2D/1D NS-NWA photoanode shows excellent photostability after irradiation with light for 5 h.

The purpose of this study is to provide summarized anthropometric data and ergonomic characteristics about Chinese auricles and categorization modes of anthropometric measurements and ear-related wearable products. 700 male and female volunteers aged 15–90 were recruited, a new measurement has been proposed and 19 ear measurements were measured in this study. 93% volunteers were right-handed people, 15 linear measurements and 3 angular measurements were taken directly on the auricle, and the angle between tragus and medial concha was measured by scanning. Most measurements increase steadily with age, auricular length has highest correlation with age (0.753, p

We apply a facile photoreduction deposition strategy to grow Au nanoparticles (NPs) on the surfaces of TiO2 nanowire arrays (TiO2/Au NWAs) as a Raman sensitive substrate. The fabricated TiO2/Au NWAs can be used as a highly sensitive and recyclable SERS sensor for detecting the rhodamine 6 G (R6 G) molecules with a concentration as low as 10−9 M. Moreover, when irradiated with UV light, the SERS sensor with high sensitivity can be fully reproduced due to the superior self-cleaning capability of the substrate. By a comparative study on the SERS activities of R6 G molecules over the substrates of pure TiO2 NWAs, pure Au NPs and TiO2/Au NWAs, as well as the photoresponse performance of pure TiO2 and TiO2/Au NWAs under visible light illumination, we provide an illuminating insight into enhanced mechanism of SERS activity for TiO2/Au NWAs. The photoresponse performances and SERS activities provide experimental evidence that enhanced SERS activity of TiO2/Au NWAs is ascribed to the efficient charge transfer among Au, TiO2 and R6 G. This work throws a new light on enhanced mechanism for SERS activity of semiconductor/noble-metal substrates, which are expected to find potential applications to fabricate highly sensitive SERS sensors for the detection of analytes.

Design of a green and sustainable approach for H2O2 synthesis is a meaningful subject. Herein, we propose a piezo-catalytic method for H2O2 production by utilizing a metal-free g-C3N4 catalyst, which has high activity for generating H2O2 only from H2O and O2 under ultrasonic vibration by means of converting mechanical energy to chemical energy. Without any organics, the ultrasonic-driven generation rate of H2O2 reached 34 μmol h−1. KMnO4 reduction experiments confirmed the generation of polarized electrons for g-C3N4 under ultra-sonication, while Au deposition on the edge of g-C3N4 after piezo-catalytic reduction of HAuCl4 indicated that the ultrasonic-derived piezoelectric polarization over g-C3N4 was along the g-C3N4 plane. The construction of C or N vacancies could change the piezoelectric response of g-C3N4, which was confirmed by Piezoresponse Force Microscopy (PFM), and the result showed that the g-C3N4 containing C or N vacancies exhibited a weaker piezoelectric effect and poorer ultrasonic-assisted catalytic performance than pristine g-C3N4 due to the impairment of the crystal structure. Our work reports the piezo-catalytic effect of g-C3N4 and it may help provide a green and sustainable process of generating H2O2 directly from water and oxygen.

The stable stabilization of uranium (U) in iron (Fe) containing environments is restricted by the reoxidation of UO2. In the current study, based on air reoxidation tests, we propose a novel two steps accumulation method to enrich microbial consortia from paddy soil. The constructed microbial consortia, denoted as the Fe–U bacteria, can co-precipitate U and Fe to form stable Fe–U solids. Column experiments running for 4 months demonstrated the production of U(IV)–O–Fe(II) precipitates containing maximum of 39.51% uranium in the presence of Fe–U bacteria. The reoxidation experiments revealed the U(IV)–O–Fe(II) precipitates were more stable than UO2. 16S rDNA high throughput sequencing analysis demonstrated that Acinetobacter and Stenotrophomonas were responsible for Fe and U precipitation, while, Caulobacteraceae and Aminobacter were crucial for the formation of U(VI)-PO4 chemicals. The proposed two steps accumulation method has an extraordinary application potential in stable immobilization of uranium in iron containing environments.

Large Low Shear Velocity Provinces (LLSVPs) in the lowermost mantle are key to understanding the chemical composition and thermal structure of the deep Earth, but their origins have long been debated. Bridgmanite, the most abundant lower-mantle mineral, can incorporate extensive amounts of iron (Fe) with effects on various geophysical properties. Here our high-pressure experiments and ab initio calculations reveal that a ferric-iron-rich bridgmanite coexists with an Fe-poor bridgmanite in the 90 mol% MgSiO3–10 mol% Fe2O3 system, rather than forming a homogeneous single phase. The Fe3+-rich bridgmanite has substantially lower velocities and a higher VP/VS ratio than MgSiO3 bridgmanite under lowermost-mantle conditions. Our modeling shows that the enrichment of Fe3+-rich bridgmanite in a pyrolitic composition can explain the observed features of the LLSVPs. The presence of Fe3+-rich materials within LLSVPs may have profound effects on the deep reservoirs of redox-sensitive elements and their isotopes., Dense Fe3+-rich bridgmanite can explain the seismic features of Large Low Shear Velocity Provinces, as it can form large-scale thermochemical piles in the deep mantle that remain stable throughout Earth’s history.

Ferromagnesite (Mg,Fe)CO3, also referred to as magnesiosiderite at high iron concentration, is a solid solution of magnesite (MgCO3) and siderite (FeCO3). Ferromagnesite is believed to enter the Earth's lower mantle via subduction and is considered a major carbon carrier in the Earth's lower mantle, playing a key role in the Earth's deep carbon cycle. Experiments have shown that ferromagnesite undergoes a pressure-induced spin crossover, accompanied by volume and elastic anomalies, in the lower-mantle pressure range. In this work, we investigate thermal properties of (Mg,Fe)CO3 using first-principles calculations. We show that nearly all thermal properties of ferromagnesite are drastically altered by iron spin crossover, including anomalous reduction of volume, anomalous softening of bulk modulus, and anomalous increases of thermal expansion, heat capacity, and Guneisen parameter. Remarkably, the anomaly of heat capacity remains prominent (up to 40%) at high temperature without smearing out, which suggests that iron spin crossover may significantly affect the thermal properties of subducting slabs and the Earth's deep carbon cycle., Comment: Main text: 24 pages and 8 figures; Supplemental Material: 8 pages, 3 tables, and 1 figure

Due to most of the current algorithms use stacked RGB information for spatial-temporal action detection, the time sequence information is easily lost in the process of convolution and down-sampling, which makes it difficult to model spatial-temporal action and limits the development of action detection. Given the current advanced pose estimation algorithm that has achieved good detection accuracy, we propose an end-to-end network that fuses RGB with skeleton to solve the problem of spatial-temporal action detection. We use RGB to describe the appearance information of object and skeleton to describe the action information. Specifically, in the first part, we generate the initial classification and location proposals based on RGB information by the SSD network. Secondly, we generate frame-level skeleton information by the current advanced pose estimation algorithm, the skeleton helps the SSD network to filter negative samples during training, and then we stack the skeleton after completion and normalization, put it into LSTM network for classification. Finally, we fuse the outputs of the SSD network and LSTM network. We believe that the introduction of skeleton information can effectively address the problem of the insufficient capacity of RGB information for spatialtemporal action modeling. It is worth noting that our skeleton information is based on advanced attitude estimation algorithms rather than annotated. For the datasets, we select the single-person action videos in UCF101 and UCF50. The final experimental results show that our method can significantly improve the action modeling ability of the neural network, and show effective results in action detection.

Understanding the groundwater quality and its factors is a key issue in the context of the use and protection of groundwater resources in agricultural areas near urbanized areas. This study assessed the groundwater quality in agricultural areas in the Pearl River Delta (PRD) by a fuzzy synthetic evaluation method and determined the main factors controlling the groundwater quality by principal component analysis (PCA). Results showed that approximately 85% of groundwater sites in agricultural lands in the PRD were good-quality (drinkable). Drinkable groundwater was 95% and 80% in fissured aquifers and porous aquifers, respectively. Poor-quality groundwater in porous aquifers was controlled by four factors according to the PCA, including the seawater intrusion, the lateral recharge and irrigation of surface water and geogenic sources for As, Fe, NH4+, and Mn, the wastewater infiltration, and the geogenic sources for iodide. By contrast, another four factors, including the infiltration of wastewater and agricultural fertilizers, the geogenic sources for heavy metals, the geogenic sources for iodide, and the irrigation of contaminated river water, were responsible for the poor-quality groundwater in fissured aquifers. Therefore, in the future, the groundwater protection in agricultural lands in the PRD should be strengthened because the majority of groundwater in these areas was good-quality and suitable for drinking and agricultural purposes. In addition, poor-quality groundwater in agricultural lands in the PRD was a small proportion and negligible because the factors for poor-quality groundwater are complicated.

Tissue regeneration in complex lesions such as the site of tumors, bacterial infection, and sites lacking blood vessels, has been a huge challenge. Therefore, developing bioactive implantable materials with multi-functional properties such as tumor destruction, bacteria growth inhibition, and angiogenesis promotion is of great significance. In this study, black CaO-SiO2-TiO2 (CST) glasses are prepared through the containerless melting approach, by which heterogeneous nucleation can be avoided and thereby glass formation becomes possible via fast quenching. This approach enables the formation of trivalent titanium (Ti3+) without using a reducing atmosphere or reducing agents. The black CST glasses are found in this study to possess a strong ability to inhibit bacteria and tumors by their excellent photothermal and photocatalytic effects. Strikingly, these glasses also promote the formation of blood vessels and accelerate the healing of chronic wounds by the synergistic effects of the photothermal effect and Si ions. Thus, this glass system can be a promising multi-functional material for tissue regeneration in complex lesions.

Hashing is an effective and widely used technology for fast approximate nearest neighbor search in large-scale images. In recent years, it has been combined with a powerful feature learning model, convolutional neural network(CNN), to boost the efficiency of large-scale image retrieval. In this paper, we introduce a new Deep Double Center Hashing (DDCH) network to learn hash codes with higher discrimination between different people and compact hash codes between the same person for large-scale face image retrieval. Our method uses a deep neural network to learn image features as well as hash codes. We use a deep CNN to extract image features and a multi-layer neural network as the hash function. The whole model is trained end-to-end. In order to learn compact and discriminative hash codes, we impose a compact constraint on the codes to force lower intra-class variations of the codes. Our constraint is formulated as a center-loss over the learned codes, which encourages hash codes to be near the hash center of the same class. In addition, new discrete hashing modules and multi-scale fusion are designed to capture discriminative and multi-scale information. We conduct experiments on the most popular datasets, YouTubeFaces and FaceScrub, and demonstrates the efficient performance of DDCH over the state-of-the-art face image hashing methods.

Groundwater pollution in urbanized areas (UAs) is commonly complicated due to various human activities. This chapter discussed the groundwater pollution in the Pearl River Delta (PRD) where high levels of urbanization and industrialization are. High levels of manganese, iron, ammonium, iodide, nitrate, and arsenic in groundwater often occur in the PRD. The reductive dissolution of iron/manganese (oxyhydr)oxides, the release of arsenic and iodide adsorbed onto iron/manganese (oxyhydr)oxides, and the mineralization of organic matter in strata are mainly responsible for high levels of manganese, iron, arsenic, iodide, and ammonium in groundwater. By contrast, high level of nitrate in groundwater originated mainly from the leakage of domestic sewage and industrial wastewater. About 5% groundwater was detected 18 organic pollutants, and naphthalene was the most frequently detected organic pollutant with detection rate of 2.51%. The occurrence of organic pollutants in groundwater originated mainly from the industrialization.

The Wu-Wentzcovitch semi-analytical method (SAM) is a concise and predictive formalism to calculate the high-pressure and high-temperature (high-PT) thermoelastic tensor (Cij) of crystalline materials. This method has been successfully applied to materials across different crystal systems in conjunction with ab initio calculations of static elastic coefficients and phonon frequencies. Such results have offered first-hand insights into the composition and structure of the Earth's mantle . Here we introduce the cij package, a Python implementation of the SAM-Cij formalism. It enables a thermoelasticity calculation to be initiated from a single command and fully configurable from a calculation settings file to work with solids within any crystalline system. These features allow SAM-Cij calculations to work on a personal computer and to be easily integrated as a part of high-throughput workflows. Here we show the performance of this code for three minerals from different crystal systems at their relevant PT s: diopside (monoclinic), akimotoite (trigonal), and bridgmanite (orthorhombic). Program summary Program title: cij CPC Library link to program files: https://doi.org/10.17632/b8xf5jh5s8.1 Developer's repository link: https://github.com/MineralsCloud/cij Licensing provisions: GNU General Public License 3 Programming language: Python 3 Nature of problem: Experimental measurements of full elastic tensor coefficients under high-pressure and high-temperature conditions are challenging and susceptible to uncertainties. Computations of thermoelastic coefficients based on the conventional density functional theory (DFT) plus quasiharmonic approximation (QHA) or ab initio molecular dynamics (AIMD) methods are computationally extremely demanding, especially for materials with low symmetries because of the revaluation of free energy for strained configurations. Solution method: Based on a semi-analytical method proposed by Wu and Wentzcovitch [1], we developed a handy code that only needs static-state elastic coefficients and phonon vibrational density of states for several equilibrium configurations at different pressure points as input to calculate the thermal elasticity. This method avoids the reevaluation of free energy for strained configurations and can be applied to all crystal systems. Reference [1] Z. Wu, R.M. Wentzcovitch, Phys. Rev. B 83 (2011) 184115.

Diamonds form in a variety of environments between subducted crust, lithospheric and deep mantle. Recently, deep source diamonds with inclusions of the high-pressure H2O-phase ice-VII were discovered. By correlating the pressures of ice-VII inclusions with those of other high-pressure inclusions, we assess quantitatively the pressures and temperatures of their entrapment. We show that the ice-VII-bearing diamonds formed at depths down to 800 ± 60 km but at temperatures 200–500 K below average mantle temperature that match the pressure-temperature conditions of decomposing dense hydrous mantle silicates. Our work presents strong evidence for coupled recycling of water and carbon in the deep mantle based on natural samples., Graphical abstract, Public summary • A novel approach was developed to assess the pressure-temperature conditions of entrapment of inclusions in diamonds • The viscoelastic relaxation of diamond has a significant effect on the evolution of pressure and temperature • Ice-VII-bearing diamonds have formed in wet, cool environments at depths down to 800 km • The coupled recycling of water and carbon is present in the deep mantle

Earth’s habitability is closely tied to its late-stage accretion, during which impactors delivered the majority of life-essential volatiles. However, the nature of these final building blocks remains poorly constrained. Nickel (Ni) can be a useful tracer in characterizing this accretion as most Ni in the bulk silicate Earth (BSE) comes from the late-stage impactors. Here, we apply Ni stable isotope analysis to a large number of meteorites and terrestrial rocks, and find that the BSE has a lighter Ni isotopic composition compared to chondrites. Using first-principles calculations based on density functional theory, we show that core-mantle differentiation cannot produce the observed light Ni isotopic composition of the BSE. Rather, the sub-chondritic Ni isotopic signature was established during Earth’s late-stage accretion, probably through the Moon-forming giant impact. We propose that a highly reduced sulfide-rich, Mercury-like body, whose mantle is characterized by light Ni isotopic composition, collided with and merged into the proto-Earth during the Moon-forming giant impact, producing the sub-chondritic Ni isotopic signature of the BSE, while delivering sulfur and probably other volatiles to the Earth., Based on Nickel isotope analysis of meteorites and terrestrial rocks, the authors suggest that the Bulk Silicate Earth has a sub-chondritic Nickel isotope composition. This signature is thought to result from the impact and accretion of a Mercury-like impactor which originated from the innermost Solar System.

Effective separation of charge carriers and substantial prolongation of charge carrier lifetime are two vital issues for a photoanode to achieve highly efficient photoelectrochemical (PEC) hydrogen generation. Herein, a Cu

The glacier recession and the runoff variation on the Qinghai-Tibet plateau conducted by the global warming is changing the regional hydrological and ecological processes. Although there is great need for the knowledge of the runoff evolution and biogenic substances migration and transformation for developing strategies for adaptive utilization of runoff, progress in study on these hydrological questions lags behind because of lack of observation dataset under harsh plateau cold conditions.In order to understand the critical zone ecohydrological dynamics and evaluate the runoff components in the Qinghai-Tibet Plateau, a series of observation and research were carried out in the Niyang River watershed, a tributary of the Yarlung Zangbo River. Four basins embed in a larger basin (1500 km2) were monitored and sampled at altitudes between 3667 to 6140 m. More than 500 samples from rain, snow, river water, spring water, glacier ice, vegetation stem, and soil were collected, with which theδ2H, δ18O, K, Ca, Na, Mg, Sr, Si, F, Cl, N, and S in the water are examined. 5 automatic hydrometric stations were established, and the water level data was sent back by Beidou satellite. The 3D laser scanning and RTK technologies were used to obtain detailed geomorphological information near the 5 current measurement section, based on which a hydrodynamic model is able to be calibrated for the discharge estimation.The δ2H and δ18O of the precipitation proposed a local meteoric water isotope line, which is parallel to the WMWL but higher in the δD~δ18O graph. The river water isotopes suggest its source is the precipitation, which are similar to the spring ground water (but the geochemical elements are quite different between the surface and ground water). The vegetation stems water and soil water (by cryogenic vacuum extraction) isotope values suggest the attribute of the river/precipitation sources, but a few observation data appear different implying using water formed by the multiple precipitation events or supplied by the higher place under a significant evaporation influence.The time series of the runoff and the snow cover and glacier variation results show that the base flow is varied obviously relate to the temperature which influence the melting processes of the glacier and frozen earth from March to August, and the rain runoff events control the flood peek. It suggests that the concentration time should be less than 10 days in the interested watershed.The tempo-spatial variation characteristics of the geochemical elements are analyzed and mapped in the interested area, which suggested relative steady water components signals contributing to the runoff. Based on which, a set of overdetermined equations are established to evaluate the quantities of different runoff components.This study could help to evaluate runoff components quantitively in Tibet where lack of data. Monitoring and studing is still going on, which is included in the 2nd comprehensive scientific investigation into Qinghai-Tibet Plateau since 2019.Funded by the NSFC project 91647111 and 91647203 included in the Runoff Change and its Adaptive Management in the Major Rivers in Southwestern China Major Research Plan.

The water content in the mantle transition zone exerts a controlling influence on the dynamical and chemical evolution of Earth, but is poorly known. In principle the water content at the top of the transition zone can be inferred by comparing the velocity and density contrasts across the 410-km seismic discontinuity with predictions based on the phase transition of olivine to wadsleyite. The high-quality elastic data of at pressure and temperature (PT) conditions of the transition zone are crucial but are very challenge for experiments to obtain. Calculating these elastic data at high PT conditions in conventional method are also very expensive. Instead, these elastic data were calculated using the method of Wu and Wentzcovitch (2011), which reduces the computational workload to tenth of the conventional method. All calculations for two phases were conducted using the same computational details as far as possible, which guarantees that the velocity and density differences between two phases have very high precise. All these calculated elastic data agree well with the available experimental data. The iron and water effect on the elasticity are also well described.With these high-quality elastic data covered the PT condition of the transition zone, we analyze the water and wadsleyite content at the top of the transition zone. We found that the water content of wadsleyite at the top of the transition zone can be well constrained when density and velocities jumps are considered together. For a pyrolitic mantle composition with ~60% olivine, our best fit is ~ 0.5 wt% water at the top of the transition zone. If the transition zone is dry, as suggested by some electrical conductivity models, the upper mantle may only contain ~ 50% olivine (Wang et al., 2019). Wang, W-Z., Walter, M.J., Peng, Y., Redfern, S., Wu, Z-Q., 2019a. Constraining olivine abundance and water content of the mantle at the 410-km discontinuity from the elasticity of olivine and wadsleyite. Earth Planet. Sci. Lett. 519, 1–11.Wu, Z-Q., Wentzcovitch, R.M., 2011. Quasiharmonic thermal elasticity of crystals: An analytical approach. Phys. Rev. B - Condens. Matter Mater. Phys. 83, 1–8. doi:10.1103/PhysRevB.83.184115

In order to reduce the misoperation of submersible pilots in the complex environment of deep sea and improve human reliability, it is a very important method to optimize the cabin space of manned submersible. In this paper, manned submersible Jiaolong is taken as an example to describe the breakthrough of traditional modes for optimizing the cabin layout of manned submersible with an aesthetic perspective of deconstruction and reconstruction thinking; the layout is optimized based on deconstruction and reconstruction from the cultural perspective of interdisciplinary. The experimental results show that the layout of manned submersible cabin is optimized by combining the theory of deconstruction and reconstruction aesthetics and human factors engineering, and the feasibility and effectiveness of this method are verified by multiobjective genetic algorithm. Deconstruction and reconfiguration layout optimization improves the human reliability of divers. It is a new method for the optimization of manned submersible cabin layout and also provides a reference for studies on the layout of similar small space.

With the abuse of pharmaceuticals in human living activities, contaminants generated in the process of drug production and discharged into natural water after usage, which results in a huge challenge to current water treatment technologies. Perovskite materials have exhibited well photocatalytic properties from the application point of view for water treatment. In this paper, perovskite LaNiO3 was co-substituted by Ce and Cu elements with enhanced photocatalytic performance for the degradation of the antibiotic (norfloxacin, NOR). The crystal structure and performance of as-synthesized co-substituted LaNiO3 photocatalyst are characterized by X‐ray diffraction (XRD), BET, scanning electron microscope (SEM), energy dispersive spectrum (EDS), Transmission Electron Microscopy (TEM), UV‐vis absorption spectroscopy, Photoluminescence (PL) spectrum, X-ray photoelectron spectroscopic spectroscopy (XPS) and photocatalysis experiments. Co-substituted LaNiO3 showed higher absorbance, photocatalytic performance, and excellent total organic carbon (TOC) removal efficiency compared with LaNiO3. The photodegradation capacity and the TOC removal efficiency are almost 2 times higher than that of pure LaNiO3. The utilization of Ce and Cu, partially substituting for La and Ni to tune physical properties of perovskite materials provides a facile way to improve the photocatalytic performance for water treatment with degradation of antibiotics.

It is of great relevance to maintain an adequate and continuous lubricant oil supply to each contact region in successive rolling point contact systems, such as rolling bearings, rolling guides, and ball screws. As a case study, we implemented laser-induced fluorescence observations of the dyed oil in a ball bearing. It is found that there exists an oil layer evolution as the rotating speed increases, especially when it reaches some critical levels. The oil layer will break up and migrate out of the rolling contact traces, while the oil distribution changes. In addition, a series of air–oil two-phase flow simulations based on computational fluid dynamics models and the volume-of-fluid method are run to reveal the forming mechanism. Flow maps are of construction with the flow patterns and the oil distribution. The critical points of the flow pattern transitions and the oil distribution changes are highly coincident with the contour lines of Ca. The force extraction shows that the pressure gradient force caused by Sommerfeld pressures has different directions at the outlet and inlet zones. They tend to attract the outlet meniscus into the low-pressure area while pushing the inlet meniscus out of the high-pressure area. As a result, the oil layer will leave and migrate out of the rolling contact traces. The capillary force will always work against the pressure gradient force. Their competition and equilibrium may determine the flow pattern transitions, the oil distribution changes, and their close relationships with Ca.

The oil redistribution in bearing during rest will greatly influence the bearing lubrication when restart. This paper presents a theoretical model to predict oil redistribution and replenishment induced by surface tension and gravity in a stationary bearing. Experiments are conducted to validate the model. The influence of different factors including oil viscosity, surface tension coefficient and initial oil layer thickness on replenishment is investigated, and the contribution of gravity and surface tension on oil migration is explored. It shows that replenishment in the stationary bearing can be positively influenced by the decrease of viscosity, the increase of surface tension coefficient and the initial oil layer.

Imidazolate-based ZIF-8 catalysts M@ZIF-8 (M = Au NR, Au@Ag NR, or Au@PtAg NRT; NR = nanorod, NRT = nanorattle), were assembled. Au NRs acted as the core for the epitaxial growth of the Ag shell, and oxidative etching of Au@Ag NRs led to Au@PtAg NRTs with K2PtCl4 aqueous solution. All metal nanorods (MNRs) and metal nanorattles (MNRTs) were well dispersed and fully encapsulated in ZIF-8. Au@PtAg NRTs encapsulated in ZIF-8 could lead to enhanced stability and selectivity for catalytic applications, combining the advantages of ZIF-8 (tailorable porosity) with the high surface area and improved optical sensitivity of rod-shaped NRTs. The catalyst Au@PtAg@ZIF-8 exhibited efficient catalytic activity and CO selectivity for the gas-phase photoreduction of CO2 with H2O.

The reduction of low-concentration carbon dioxide with water to organic fuels is still a huge challenge. In this study, we successfully designed the partially oxidized cobalt nanoparticles coated by the nitrogen-doped carbon layer (Co@NC) of 2–8 nm via a facile method and then interspersed with different amount of Pt nanoparticles. The Co@NC decorated with 1 wt% Pt exhibits the best ability for CO2 reduction to CH4 and a CH4 production rate of 14.4 μmol·g−1·h−1 is achieved. It is worth noting that the system is carried out under low-concentration CO2 (400 ppm) circumstance without any sacrificial agent, which could be meaningful to the design of catalysts for atmospheric CO2 reduction.

Photocatalytic nitrogen fixation, as a low-cost and promising technology, needs efforts to explore the photocatalyst with high activity and stability. In this study, the polyoxometalate (POM) cluster of [H4SiO40W12] (SiW12) has been successfully covalently combined with the KOH-modified graphitic carbon nitride nanosheets (K-C3N4) through the phosphate-bridged strategy. With POM acting as the co-catalyst, SiW12/K-C3N4 nanocomposites show excellent photocatalytic nitrogen fixation efficiency (353.2 μM g−1 h−1) in water under light-irradiation. It can be ascribed to the enhanced separation efficiency of charge carriers through the formation of “phosphate-bridged” bonds between K-C3N4 and SiW12, and the increased oxidation capacity of water by bridging SiW12. Moreover, K doping and bridging SiW12 improves the adsorption and activation of nitrogen, which can be conductive to the reduction of nitrogen to ammonia. This work provides a feasible route to design and synthesize nanocomposite materials with exceptional performance for photocatalytic nitrogen fixation.