Based on the principle of laser range measuring technology and precision angle division technology, a new measurement method of three-dimensional Laser Scanning for the volume of railway tank car and ...tank container is studied. The method mainly includes acquisition of point cloud data, processing the point cloud and volume calculation. In the processing point cloud, the T-Fo de-noising method is designed which is a new and efficient de-noising method. Three-dimensional laser scanning method, volumetric comparison method, the geometric method are compared, the results show that measurement by using three-dimensional laser scanning technology of the volume of railway tank car (container) is more accurate, safe, efficient, automatic. The expanded measurement uncertainty of three-dimensional laser scanning method is 3 × 10−3 (k = 2).
Tetracycline antibiotics (TCs) are one kind of broad spectrum bacteriostatic agents. However, excessive use of TCs will have a threat to the environment and human health. Therefore, it is necessary ...to develop a simple method for direct detection of TCs. Based on intrinsic peroxidase-like activity of gold nanoclusters (AuNCs), we used TC-specific aptamers (Apt) to improve the catalytic activity of AuNCs toward the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation by H2O2, and established a colorimetric sensing platform for TCs. The catalytic enhancement by Apt allows for sensitive colorimetric detection of TCs, and Apt as molecular recognition elements can specifically combine with TCs leading to high selectivity. This developed sensing platform can quantitatively detect TCs in the concentration range of 1–16 μM with a limit of detection (LOD) as low as 46 nM. Interestingly, the naked-eye detection capability of this method is estimated to be 0.5 μM. Finally, the detection of TCs in real samples like drugs and milk was validated.
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•A gold nanoclusters-based colorimetric aptasensor for tetracycline was presented.•Specificity and sensitivity of gold nanoclusters were greatly improved by aptamer.•The aptamer-enhanced peroxidase-like activity of gold nanoclusters was validated.•The sensor can accurately and reproducibly detect tetracycline in drugs and milk.
2D metal‐halide perovskites have attracted intense research interest due to superior long‐term stability under ambient environments. Compared to their 3D analog, the alternate arrangement of organic ...and inorganic layers leads to forming a multilayer quantum well (MQW), which endows 2D perovskites with anisotropic optoelectronic properties. In addition, the spacer layer functions as a hydrophobic barrier to effectively prevent 2D perovskite films from ion migration and moisture penetrating, thus realizing outstanding stability. Recently, 2D perovskites have been widely developed with abundant species. The stunning photovoltaic performance with the coexistence of long‐term stability and high‐power conversion efficiency (PCE) has been realized in 2D perovskite solar cells (PSCs), which paves an avenue for commercialization of PSCs. This review begins with an introduction of crystal structure and crystallization kinetics to illustrate the unique layer characters in 2D perovskites. Then, electron structure, excitons, dielectric confinement, and intrinsic stability properties are discussed in detail. Next, the photovoltaic performance based on recent Ruddlesden–Popper (RP), Dion–Jacobson (DJ), and alternating cations in the interlayer (ACI) phase 2D‐PSCs is comprehensively summarized. Finally, the confronting challenges and strategies toward structural design and optoelectronic studies of 2D perovskites are proposed to offer insight into the advanced underlying properties of this family of materials.
This review presents state‐of‐the‐art developments on 2D metal‐halide perovskite solar cells. The basic crystal structure, properties, and device photovoltaic performance on 2D perovskites are discussed in detail. Besides, the confronting challenges and corresponding strategies are proposed to offer insight into the underlying properties of this family of materials.
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•A novel CaO2 bead was prepared to recover TSCFAs and P from iron-rich WAS.•Abundant acetate and Fe2+ in anaerobic supernatant were obtained after CaO2 beads treatment.•About 9% of P ...in sludge was recovered as Fe-P and Ca-P compounds on beads.•The decrease of Fe-phosphates and Fe-oxides in WAS were due to different mechanisms.•CaO2 beads effectively enriched DIRB and promoted iron-reduction related genes.
A novel composite CaO2 bead was prepared to improve total short-chain fatty acids (TSCFAs) production and phosphorus (P) recovery from iron-rich waste activated sludge (WAS) during ambient anaerobic fermentation. Results showed that CaO2 mass percentage of 5% and CaCl2:nylon66 = 1:1 (mass ratio) were the optimal prescription for the preparation of CaO2 beads with porous structure, loose morphology, and sustained-release of CaO2. The highest TSCFAs production (356 mg/g VSS) was observed and about 9% of P in sludge could be recovered on beads. The decrease of Fe-phosphate and Fe-oxides in the sludge were due to different mechanisms. Microbial community analyses showed that CaO2 beads effectively enriched dissimilatory iron-reducing bacteria (DIRB) and promoted iron-reduction related genes. After fermentation, the P-rich beads are easy to separate from sludge for further P recovery, and the supernatant carrying abundant acetate and Fe2+ can be returned to the wastewater treatment line to improve nutrient removal.
The current outbreak of coronavirus disease-2019 (COVID-19) poses unprecedented challenges to global health
. The new coronavirus responsible for this outbreak-severe acute respiratory syndrome ...coronavirus 2 (SARS-CoV-2)-shares high sequence identity to SARS-CoV and a bat coronavirus, RaTG13
. Although bats may be the reservoir host for a variety of coronaviruses
, it remains unknown whether SARS-CoV-2 has additional host species. Here we show that a coronavirus, which we name pangolin-CoV, isolated from a Malayan pangolin has 100%, 98.6%, 97.8% and 90.7% amino acid identity with SARS-CoV-2 in the E, M, N and S proteins, respectively. In particular, the receptor-binding domain of the S protein of pangolin-CoV is almost identical to that of SARS-CoV-2, with one difference in a noncritical amino acid. Our comparative genomic analysis suggests that SARS-CoV-2 may have originated in the recombination of a virus similar to pangolin-CoV with one similar to RaTG13. Pangolin-CoV was detected in 17 out of the 25 Malayan pangolins that we analysed. Infected pangolins showed clinical signs and histological changes, and circulating antibodies against pangolin-CoV reacted with the S protein of SARS-CoV-2. The isolation of a coronavirus from pangolins that is closely related to SARS-CoV-2 suggests that these animals have the potential to act as an intermediate host of SARS-CoV-2. This newly identified coronavirus from pangolins-the most-trafficked mammal in the illegal wildlife trade-could represent a future threat to public health if wildlife trade is not effectively controlled.
In this paper,we establish the existence of the global weak solutions for the nonhomogeneous incompressible magnetohydrodynamic equations with Navier boundary conditions for the velocity field and ...the magnetic field in a bounded domain Ω (∈) R3.Furthermore,we prove that as the viscosity and resistivity coefficients go to zero simultaneously,these weak solutions converge to the strong one of the ideal nonhomogeneous incompressible magnetohydrodynamic equations in energy space.
Freestanding MoS
2
nanosheets with different sizes were prepared through a simple exfoliated method by tuning the ultrasonic time in the organic solvent. Magnetic measurement results reveal the clear ...room-temperature ferromagnetism for all the MoS
2
nanosheets, in contrast to the pristine MoS
2
in its bulk form which shows diamagnetism only. Furthermore, results indicate that the saturation magnetizations of the nanosheets increase as the size decreases. Combining the X-ray photoelectron spectroscopy, transmission electron microscopy, and electron spin resonance results, it is suggested that the observed magnetization is related to the presence of edge spins on the edges of the nanosheets. These MoS
2
nanosheets may find applications in nanodevices and spintronics by controlling the edge structures.
Near-infrared (NIR) fluorescence is a noninvasive, highly sensitive, and high-resolution modality with great potential for in vivo imaging. Compared with "Always-On" probes, activatable NIR ...fluorescent probes with "Turn-Off/On" or "Ratiometric" fluorescent signals at target sites exhibit better signal-to-noise ratio (SNR), wherein enzymes are one of the ideal triggers for probe activation, which play vital roles in a variety of biological processes. In this review, we provide an overview of enzyme-activatable NIR fluorescent probes and concentrate on the design strategies and sensing mechanisms. We focus on the aggregation/dispersion state of fluorophores after the interaction of probes and enzymes and finally discuss the current challenges and provide some perspective ideas for the construction of enzyme-activatable NIR fluorescent probes.
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•The top-down approach can model the spatial distribution of industrial water use.•Industrial scale and technology level impact changes in industrial water use.•The proposed method ...contributes to the sustainable use of water resources.
Understanding changes in industrial water use at finer spatial scales is critical for regional water allocation and sustainability. This study employs a top-down method based on multi-source data to estimate the industrial water use at 1 km × 1 km resolution in the Beijing-Tianjin-Hebei (BTH) region during 2000–2019. Statistical data from municipalities and prefectures are used to assess the accuracy of simulated industrial water use. During the validation period, all accuracy validation indices (R, NSE, |RE|, RMSE) have achieved good results, indicating that the method is credible. In addition, industrial water use at the county level in BTH has a strong spatial correlation with 99% confidence. Spatiotemporal change pattern mainly depends on the industrial scale and technical level of prefecture-level cities, and the economic environment will also contribute to changes in the annual industrial water use in BTH. The method provides a reference for high-resolution estimation of industrial water use and can also be applied to regional water management and allocation.