C2H3LiO2·2H2O was firstly used as the lithium resource to synthesize precursor Li2TiO3. Melting of C2H3LiO2·2H2O (at 66 °C) during the early calcination stage can form liquid–solid phase and ...remarkably improve mixing of C2H3LiO2·2H2O and TiO2. Besides, huge heat and gases released during the reaction of dehydrated C2H3LiO2·2H2O and TiO2 (between 380 °C and 515 °C) accelerates the nucleation process and effectively inhibited agglomeration, which leads to a smaller particle size of Li2TiO3 (∼70 nm). Subsequently, Adsorption rate constant of obtained lithium ion sieve H2TiO3 reaches 0.0508 g/(mg·h). Seperation factor α (Li/Mg) reaches 5441.17, and lithium ion uptake of synthesized H2TiO3 could remain around 24.5 vmg/g after five adsorption–desorption cycles, meaning better adsorption selectivity and stability of lithium ion for West Taijinar Salt Lake brine.
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•C2H3LiO2·2H2O and TiO2 were firstly applied to synthesize lithium adsorbent via solid state method.•Reaction mechanism between C2H3LiO2·2H2O and TiO2 was analyzed.•Seperation factor α (Li/Mg) in West Taijinar Lake reaches 5441.17.•Adsorption uptake remains 24.5 mg/g after 5 cycles in West Taijinar Salt Lake brine.
Monoclinic β-Li2TiO3 (LTO) is regarded as a lithium adsorbent precursor. In order to inhibit agglomeration during solid state reaction, C2H3LiO2·2H2O instead of Li2CO3 was firstly used as the lithium resource to synthesize LTO. Lithium ion sieve H2TiO3 (HTO) was then obtained by acid treatment of LTO. Physicochemical properties of obtained LTO and HTO were characterized via powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size distribution analysis (PSD). Lithium adsorption selectivity and stability of prepared HTO for West Taijinar Salt Lake were investigated. Solid state reaction mechanism of C2H3LiO2·2H2O and TiO2 was investigated by TG-DTA analysis. Results show that melting of C2H3LiO2·2H2O (at 64.5 °C) during the early calcination stage could form liquid–solid phase and remarkably improve mixing of C2H3LiO2·2H2O and TiO2. Compared to Li2CO3 used as the lithium resource, huge heat and gases released during the reaction of dehydrated C2H3LiO2·2H2O and TiO2 (between 380 °C and 515 °C) accelerate the nucleation process and effectively inhibits agglomeration, which leads to a smaller particle size (∼70 nm). It is shown that lithium uptake and adsorption rate were improved because of easier mass transfer during the ion-exchange process. Lithium adsorption behavior could be well described by the Langmuir isotherm and pseudo-second-order kinetic model. Seperation factor α (Li/Mg) of obtained HTO in West Taijinar Salt Lake brine reached 5441.17, meaning remarkable lithium adsorption selectivity in real lake brine. Besides, adsorption uptake remained 24.5 mg/g after 5 cycles in West Taijinar Salt Lake brine, which indicates obtained HTO has good stability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•The trend of spread of the infected area was examined using 2013 as the node.•Pine wilt disease spread in a pattern of “spread - stabilization - outbreak” throughout the country.•The direction of ...spread was from south to north, coast to inland, developed to developing areas, and multiple areas were affected with multiple outbreaks.•The spread of pine wilt disease was distributed across multiple areas with multiple outbreaks and showed significant characteristics of spatiotemporal aggregation.
Pine wilt disease is a worldwide forest disease, caused by an invasive species in China that is highly dangerous. It caused huge losses to the Chinese ecological environment, natural landscape and social economy. The existing studies on the spread of pine wilt disease have been limited in scope and duration and have been fragmented. This study aims to apply macroscopic analysis to reveal the spatiotemporal spread of pine wilt disease in mainland China and provide a scientific basis for the control of pine wilt disease. According to statistical pine wilt disease data from 1998 to 2017 and NDVI data for China, we showed relevant information concerning the disease graphically, mapped the distribution of the infected area in ArcGIS and performed scan statistics in SaTScan to detect spatiotemporal clusters. This study applied macroscopic analysis of the evolution of pine wilt disease over a long duration, revealing the occurrence, spatial distribution and aggregation of infections and the spatial and temporal patterns of the disease. The results show that the pine wilt disease is concentrated in southeastern China and has a strong spatial correlation. The trend of spread of the infected area was examined using 2013 as the node. Pine wilt disease spread in a pattern of “spread - stabilization – outbreak – full outbreak” throughout the country. The direction of spread was from south to north, coast to inland, developed to developing areas, and multiple areas were affected with multiple outbreaks. According to the spatiotemporal scan results, disease occurrence in the long-infested areas of Jiangsu, Anhui, Zhejiang, Shanghai and Guangdong Provinces showed high clustering, and new clusters were formed in Sichuan, Chongqing and there surrounding areas with the spread of the disease. The spread of pine wilt disease was distributed across multiple areas with multiple outbreaks and showed significant characteristics of spatiotemporal aggregation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Electrocatalytic reduction of CO2 to useful chemicals is a prospective strategy that can address both carbon emission abatement and sustainable energy development. Due to the low solubility and ...intrinsic inertness of CO2, efficient CO2 conversion remains a challenge in aqueous CO2 electroreduction. Herein we report that a copper hollow fiber of gas-diffusion electrode constructed by a phase-inversion/sintering process enables CO2 reduction to formate maintains considerable faradaic efficiency (80%) at high current density (210 mA∙cm−2), delivering its formate yield about 16 and 30 times those of copper foam and copper foil, respectively. CO2 molecules are forced to penetrate through the porous wall of Cu hollow fiber electrode, resulting in CO2 effective activation and compulsive interaction with active sites, which synergistically facilitates formate formation. This work indicates a positive potentiality of employ a distinct gas-diffusion electrode of hollow fiber to optimize reaction kinetics for efficient and selective electroreduction of CO2 to formate.
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•Copper hollow fiber is constructed by a phase-inversion/sintering process.•CO2 effective activation and compulsive interaction lead to efficient conversion.•HCOOH yield reaches 2677 μmol∙h−1∙cm−2 with as high as current density 210 mA∙cm−2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The high detected frequencies of hexaconazole (Hex) and arsenic (As) increased the probabilities of their co-existence in agricultural products. However, the combined toxicity effect and mechanism of ...action for these two pollutants were still unclear. In this study, an untargeted metabolomics method with ultra high performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS) was developed to monitor the changes of endogenous metabolites and metabolism pathways in mice liver. Our study revealed that significant differences in metabolomics profiles were observed after Hex, As, and Hex+As exposure for 90 d. Hex exposure altered 54 metabolites and 11 pathways significantly which were mainly lipid-related. For As exposure, 63 metabolites and 9 pathways were affected most of which were amino acid-related. Hex+As induced 93 metabolites changes with 34% was lipids and lipid-like molecules and 22% was organic acids and derivatives. Hex+As exposure shared the pathways that altered by Hex and As indicated that the interaction of Hex and As might be independent action. The results of this study could provide an important insight for understanding the mechanism of combined toxicity for Hex and As and be helpful for evaluating their health risk to human.
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•Hexaconazole exposure mainly altered lipid-related metabolites and pathways.•Arsenic exposure mainly changed amino acid-related metabolites and pathways.•Hexaconazole+arsenic shared most metabolites and pathways with hexaconazole or arsenic.•The interaction of hexaconazole and arsenic was independent action.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pine wood nematode disease is a devastating pine disease that poses a great threat to forest ecosystems. The use of remote sensing methods can achieve macroscopic and dynamic detection of this ...disease; however, the efficiency and accuracy of traditional remote sensing image recognition methods are not always sufficient for disease detection. Deep convolutional neural networks (D-CNNs), a technology that has emerged in recent years, have an excellent ability to learn massive, high-dimensional image features and have been widely studied and applied in classification, recognition, and detection tasks involving remote sensing images. This paper uses Gaofen-1 (GF-1) and Gaofen-2 (GF-2) remote sensing images of areas with pine wood nematode disease to construct a D-CNN sample dataset, and we train five popular models (AlexNet, GoogLeNet, SqueezeNet, ResNet-18, and VGG16) through transfer learning. Finally, we use the “macroarchitecture combined with micromodules for joint tuning and improvement” strategy to improve the model structure. The results show that the transfer learning effect of SqueezeNet on the sample dataset is better than that of other popular models and that a batch size of 64 and a learning rate of 1 × 10−4 are suitable for SqueezeNet’s transfer learning on the sample dataset. The improvement of SqueezeNet’s fire module structure by referring to the Slim module structure can effectively improve the recognition efficiency of the model, and the accuracy can reach 94.90%. The final improved model can help users accurately and efficiently conduct remote sensing monitoring of pine wood nematode disease.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Pine wilt disease
caused by the pinewood nematode
Bursaphelenchus xylophilus
has led to the death of a large number of pine trees in China. This destructive disease has the characteristics of bring ...wide-spread, fast onset, and long incubation time. Most importantly, in China, the fatality rate in pines is as high as 100%. The key to reducing this mortality is how to quickly find the infected trees. We proposed a method of automatically identifying infected trees by a convolution neural network and bounding box tool. This method rapidly locates the infected area by classifying and recognizing remote sensing images obtained by high resolution earth observation Satellite. The recognition accuracy of the test data set was 99.4%, and the remote sensing image combined with convolution neural network algorithm can identify and determine the distribution of the infected trees. It can provide strong technical support for the prevention and control of
pine wilt disease
.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Corrosion critically impacts bond performance in steel-reinforced concrete (SRC) structures. In this study, we investigate the impact of corrosion on bond-slipping between steel components and ...concrete within SRC structures. Initially, SRC specimens were subjected to electrochemical corrosion tests to induce varying corrosion rates. Then, pull-out tests were conducted to study the specimens' failure modes, bond stress–slip curves, and displacement distribution. The experimental results indicate that lower corrosion rates can increase bond strength due to enhanced steel surface roughness. As the corrosion rate increased from 0% to 5%, the initial bond stress, peak bond stress, and residual bond stress increased by 133%, 101%, and 102%, respectively. However, when the corrosion rate increased from 5% to 15%, these stresses decreased by 57.1%, 49.6%, and 49.6%, respectively. Furthermore, with an increase in corrosion rate from 15% to 20%, the initial, peak, and residual bond stresses decreased by 100%, 67.6%, and 69.0%, respectively. Corrosion considerably affected the initial and peak slipping observed between the steel components and the concrete, yet its impact on residual slip was relatively minor. In addition, a nonlinear finite element model for characterising the corrosion and pull-out tests was developed and validated according to the experimental results. The numerical results showed that the four shear transfer mechanisms, including chemical bonding, micromechanical interlocking, macromechanical interlocking, and rust interface bonding, exhibited distinct behaviours at different loading stages. Finally, a parametric study was conducted using a finite element model. With variations in corrosion rates, four modes of cracking patterns on the concrete surface were observed.
•Accelerated corrosion and push-out tests were conducted on SRC specimens.•Failure modes, bond stress–slip curves, and displacement distributions on the concrete surface were obtained.•Experimental results show that increased surface roughness at low corrosion rates can enhance bond strength.•The established nonlinear finite element model can quantify and elucidate the load transfer mechanism.•Parametric studies reveal that a diversity of crack patterns occur on the concrete surface with varying corrosion rates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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