Robust ferromagnetism of single crystalline CoxZn1−xO (0.3 ≤ x ≤ 0.45) epitaxial films with high Co concentration

In contrast to conventional dilute magnetic semiconductors with concentrations of magnetic ions of just a few percent, here, we report the fabrication of epitaxial Cox Zn 1− xO single crystalline films with Co concentrations from x = 0.3 up to 0.45 by radio-frequency oxygen-plasma-assisted molecular beam epitaxy. The films retain their single crystalline wurtzite structure without any other crystallographic phase from precipitates, based on reflection high energy electron diffraction, X-ray diffraction, transmission electron microscopy, and Raman scattering. The results of X-ray diffraction, optical transmission spectroscopy, and in-situ X-ray photoelectron spectroscopy confirm the incorporation of Co2+ cations into the wurtzite lattice. The films exhibit robust ferromagnetism and the magneto-optical Kerr effect at room temperature. The saturation magnetization reaches 265 emu/cm3 at x = 0.45, which corresponds to the average magnetic moment of 1.5 μB per Co atom

Synergistic Effects of La and Y on the Microstructure and Mechanical Properties of Cast Al-Si-Cu Alloys

The effects of La and Y on the microstructure and mechanical properties of cast Al-Si-Cu alloys were investigated by X-ray diffractometer (XRD), optical microscope (OM), and scanning electron microscope (SEM). The results indicated that the addition of La and Y had a great effect on the refinement of α-Al grains, the modification of eutectic Si phase, and the reduction of β-Al5FeSi length in Al-Si-Cu alloys. The A380 + 0.6 wt.% La/Y alloy exhibited the best microstructure and mechanical properties. The UTS and EI of the A380 + 0.6 wt.% La/Y alloy were 215.3 MPa and 5.1%, which were 22.9% and 37.8% higher than those of the matrix alloy, respectively. In addition, neither Al11La3 nor Al3Y generated by the addition of La and Y could not serve as the nucleation core of α-Al grains, so the grain refinement of α-Al originated from the growth limitation and constitutional supercooling. Since La and Y promote twinning generation and constitutional supercooling, the eutectic Si phase also changed from stripe-like to short fibrous or even granular and was significantly refined. Furthermore, thermodynamic calculations indicated that the Al11La3 phase was formed first and the Al3Y phase was generated on the Al11La3 phase

Effects of biopolymer ratio and pH value on the complex formation between whey protein isolates and soluble Auricularia auricular polysaccharides

Biopolymer complexes fabricated by proteins and neutral polysaccharides have some specific and innovative functionalities. A better understanding of the interactions among these biopolymers might provide new insight into the applications of the complexes. Therefore, this study aimed to investigate the structural characteristics and molecular interaction mechanisms of whey protein isolates (WPI) and Auricularia auricular polysaccharides (APs). The turbidity analysis confirmed that the pH value and mixing ratio of the two polymers had strong effects on the formation of the APs-WPI complexes. All dispersions formed soluble complexes at approximately pH = 6.0 (pHc). APs-WPI self-assembles exhibited physically cross-linked networks under higher APs proportions, while they formed spherical complexes at higher WPI ratios. The addition of APs could alter the secondary structure of WPI, and the most noticeable changes were located in the regions of β-sheet and β-turn as confirmed by circular dichroism (CD) analysis. A molecular docking study showed that the amino acid residues of β-lactoglobulin complexed with the –COOH and –OH groups of APs. Hydrogen bonds and hydrophobic interactions, which were nonbonding contributions, played a key role in the formation of the APs-WPI complex. This study provided a basis for the development and application of APs in WPI-based beverages

A new high-precision timely monitoring and metering system for early kick and loss

Kick and loss are two complicated incidents that affect the construction safety in oil and gas well drilling. The commonly-used kick/loss monitoring methods are disadvantageous with monitoring lag and low metering precision, which may cause well collapse, pipe sticking and well blowouts due to untimely detection and improper treatment. In this paper, a new type of kick/loss monitoring and metering system was designed based upon a comparative analysis of several kick/loss monitoring methods commonly used on rig sites. This new system has the functions of early monitoring and alarm, kick/loss velocity metering, total loss metering and automatic filling, and its feasibility was verified through laboratory experiments. And the following research results were obtained. First, the monitoring tank of this new system is divided into two chambers, i.e., a main chamber and a secondary chamber. The return of drilling fluid partially flows back to the shale shaker through the main chamber, and the rest overflows into the secondary chamber. Second, the internal cross section area of the secondary chamber is small, which increases the response sensitivity to liquid level change, so kick/loss can be detected in time. Third, the water head of the outlet pipeline of the main chamber remains constant and the outlet flow is stable, so kick/loss velocity and total kick/loss can be calculated quantitatively based on the change of liquid level in the secondary chamber. And the monitoring error of kick/loss velocity is less than 8%. Fourth, in the process of tripping out, the drilling fluid in the monitoring tank flows into the wellbore under the action of self weight to keep the full liquid level of the wellbore all the time. As a result, lagged filling and partial filling are eliminated. In conclusion, this new kick/loss monitoring system is economical and practical, and giving a full play to the advantages of ground survey and alarm timely and accurately. Keywords: Early kick, Early loss, Monitoring and metering system, Main and secondary chambers, Monitoring tank, Leakage velocity, Total loss, Automatic fillin

A Novel Approach for the Detection of Standing Tree Stems from Plot-Level Terrestrial Laser Scanning Data

Tree stem detection is a key step toward retrieving detailed stem attributes from terrestrial laser scanning (TLS) data. Various point-based methods have been proposed for the stem point extraction at both individual tree and plot levels. The main limitation of the point-based methods is their high computing demand when dealing with plot-level TLS data. Although segment-based methods can reduce the computational burden and uncertainties of point cloud classification, its application is largely limited to urban scenes due to the complexity of the algorithm, as well as the conditions of natural forests. Here we propose a novel and simple segment-based method for efficient stem detection at the plot level, which is based on the curvature feature of the points and connected component segmentation. We tested our method using a public TLS dataset with six forest plots that were collected for the international TLS benchmarking project in Evo, Finland. Results showed that the mean accuracies of the stem point extraction were comparable to the state-of-art methods (>95%). The accuracies of the stem mappings were also comparable to the methods tested in the international TLS benchmarking project. Additionally, our method was applicable to a wide range of stem forms. In short, the proposed method is accurate and simple; it is a sensible solution for the stem detection of standing trees using TLS data

A simple terrain relief index for tuning slope-related parameters of LiDAR ground filtering algorithms

Ground filtering is an essential procedure in almost all LiDAR applications. However, most existing ground filtering algorithms require different amounts of user input to manually set up initial parameters, such as terrain relief amplitude and average slope, which is subjective, time consuming, and prone to errors. Here, we propose a simple terrain relief index derived from raw airborne LiDAR data to automatically tune the slope-related parameters of ground filtering algorithms. The terrain relief index is a ratio between the height difference of the entire point cloud and the maximum above ground level of non-ground points. The latter variable can be estimated with the maximum local height difference of raw LiDAR data through gridding. We validated our method using the benchmark airborne LiDAR datasets provided by the International Society for Photogrammetry and Remote Sensing. The results showed a high correlation (r = 0.876) between the terrain relief index and the referential terrain relief amplitude. The degree of correlation was greater across larger areas (r = 0.926) than small areas (r = 0.861) regardless of the type of land cover (e.g., city or forest). The terrain relief index was introduced into two existing filtering algorithms: Cloth Simulation Filtering (CSF) and Progressive Morphological (PM) Filter, by relating the terrain relief index to the cloth rigidness of the CSF and the slope threshold of the PM filter. To compare the results, the two algorithms were implemented both with manually tuned parameters and with the parameters derived from the terrain relief index. The results showed that there was only a slight discrepancy in average Total Error (0.1%) between them in the CSF, which means that the terrain relief index can automatically determine the cloth rigidness without noticeable loss of accuracy. The average difference between the slope threshold provided by the terrain relief index and the manually tuned optimal slope threshold was 0.142 rad (8.136°) for the PM filter, which is acceptable relative to manually parameter setting without any prior knowledge. The terrain relief index can estimate the terrain relief amplitude from raw airborne LiDAR data, and the parameter settings suggested in this paper for the filtering algorithm can improve automation

One pot preparation of muti-mode nanoplatform to combat ovarian cancer

Ovarian cancer is one of the most common gynecological cancers with high mortality rate. The battle against ovarian cancer usually impaired by the evolved multidrug resistance (MDR) phenotype as well as metastasis in cancers, which urgently call for the development of multi-mode strategies to overcome the MDR and reduce metastasis. Considering the good benefits of ferroptosis and photothermal therapy (PTT) in cancer management, we herein proposed a facile way to construct nanoparticle platform (Fe-Dox/PVP) composed of ferric chloride, doxorubicin (Dox) and polyvinyl pyrrolidone (PVP) for the multi-mode therapy of ovarian cancer using chemotherapy, ferroptosis and mild hypothermia PTT. Our results demonstrated that Fe-Dox/PVP with mild hypothermia was shown to have improved endosomal escape/drug delivery, enhanced ferroptosis induction and good tumor targeting effects. Most importantly, the integration of all three effects into one platform provided increased anti-metastasis effect and promising in vitro/in vivo anticancer performance with high biocompatibility. In this study, we offer a facile and robust way to prepare a multi-mode nanoplatform to combat ovarian cancer, which can be further extended for the management of many other cancers

Effects of Vegetation Change on Soil Erosion by Water in Major Basins, Central Asia

The uncertainties in soil erosion (SE) are further intensified by various factors, such as global warming, regional warming and humidification, and vegetation cover changes. Moreover, quantitative evaluations of SE in major basins of Central Asia (CA) under changing environments have rarely been conducted. This study conducted quantitative evaluation of SE in four major basins (Syr Darya Basin (SDB), Amu Darya Basin (ADB), Ili River Basin (IRB) and Tarim River Basin (TRB) using the Revised Universal Soil Loss Equation (RUSLE) and analyzed the main driving factors. SE quantities in the basins presented relatively consistent upward fluctuating trends from 1982 to 2017. Vegetation cover variation fluctuated significantly from 1982 to 2017. Specifically, vegetation cover decreased continuously in SDB, ADB, and IRB, but increased gradually in TRB. Pixels with positive spatial variation of vegetation mainly occurred around lakes and oases near rivers. The Normalized Difference Vegetation Index (NDVI) showed higher correlation with precipitation (80.5%) than with temperature (48.3%). During the study period, the area of arable land (AL) exhibited the largest change among all land use types in CA. Under long-term human activities, the proportion of NDVI of other land types converting to AL was the highest. In the structural equation model (SEM), precipitation, temperature, Shannon Diversity Index (SHDI), and NDVI strongly influenced SE. Overall, the major basins in CA were jointly affected by climate, human activities, and vegetation. Specifically, climatic factors exerted the strongest influence, followed by SHDI (human activities). SE was found to be relatively serious in ADB, SDB, and IRB, with SE in SDB even approaching that in the Loess Plateau. Under the background of global changes, appropriate water and land resource management and optimization configurations should be implemented in CA with reference to TRB in order to relieve local SE problems

Effects of Vegetation Change on Soil Erosion by Water in Major Basins, Central Asia

The uncertainties in soil erosion (SE) are further intensified by various factors, such as global warming, regional warming and humidification, and vegetation cover changes. Moreover, quantitative evaluations of SE in major basins of Central Asia (CA) under changing environments have rarely been conducted. This study conducted quantitative evaluation of SE in four major basins (Syr Darya Basin (SDB), Amu Darya Basin (ADB), Ili River Basin (IRB) and Tarim River Basin (TRB) using the Revised Universal Soil Loss Equation (RUSLE) and analyzed the main driving factors. SE quantities in the basins presented relatively consistent upward fluctuating trends from 1982 to 2017. Vegetation cover variation fluctuated significantly from 1982 to 2017. Specifically, vegetation cover decreased continuously in SDB, ADB, and IRB, but increased gradually in TRB. Pixels with positive spatial variation of vegetation mainly occurred around lakes and oases near rivers. The Normalized Difference Vegetation Index (NDVI) showed higher correlation with precipitation (80.5%) than with temperature (48.3%). During the study period, the area of arable land (AL) exhibited the largest change among all land use types in CA. Under long-term human activities, the proportion of NDVI of other land types converting to AL was the highest. In the structural equation model (SEM), precipitation, temperature, Shannon Diversity Index (SHDI), and NDVI strongly influenced SE. Overall, the major basins in CA were jointly affected by climate, human activities, and vegetation. Specifically, climatic factors exerted the strongest influence, followed by SHDI (human activities). SE was found to be relatively serious in ADB, SDB, and IRB, with SE in SDB even approaching that in the Loess Plateau. Under the background of global changes, appropriate water and land resource management and optimization configurations should be implemented in CA with reference to TRB in order to relieve local SE problems

Reducing Threading Dislocations of Single-Crystal Diamond via In Situ Tungsten Incorporation

A lower dislocation density substrate is essential for realizing high performance in single-crystal diamond electronic devices. The in-situ tungsten-incorporated homoepitaxial diamond by introducing tungsten hexacarbonyl has been proposed. A 3 × 3 × 0.5 mm3 high-pressure, high-temperature (001) diamond substrate was cut into four pieces with controlled experiments. The deposition of tungsten-incorporated diamond changed the atomic arrangement of the original diamond defects so that the propagation of internal dislocations could be inhibited. The SEM images showed that the etching pits density was significantly decreased from 2.8 × 105 cm−2 to 2.5 × 103 cm−2. The reduction of XRD and Raman spectroscopy FWHM proved that the double-layer tungsten-incorporated diamond has a significant effect on improving the crystal quality of diamond bulk. These results show the evident impact of in situ tungsten-incorporated growth on improving crystal quality and inhibiting the dislocations propagation of homoepitaxial diamond, which is of importance for high-quality diamond growth