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The direct-imaging exploration can obtain comprehensive physical information of exoplanets, which is a key technology to search for extraterrestrial life in the future. In this paper, based on our recent high-contrast imaging data of ground-based telescope, the newly discovered multi-star candidates are presented. In the early stage, combined with the ability of high-contrast imaging equipment for the exoplanets in the ground-based system, we select about 1000 targets from published works which are compiled using the catalogs released by Gaia. These targets are distributed in different young star clusters. Recently, we used Hale Telescope at Palomar Observatory to carry out high-contrast imaging observation on 42 of the above targets in the K-band. Most of the observed targets are 7.5–14 in the V-band. In 2019, after two rounds of observation, we discover six multi-star system candidates. It is however difficult to find out whether these targets are single-star or multi-star systems in Gaia DR2 (Data Release 2) catalog and Gaia EDR3 (early Data Release 3) catalog. [ABSTRACT FROM AUTHOR]

The gut microbiome is a complex ecosystem that contributes to host nutrition and health. However, our current knowledge of the relationship between ambient temperature and gut microbiota of poultry is still limited. The objective of the present study was to characterize the intestinal microbiota of ducks exposed to high ambient temperature. Sixty 60-day-old Shaoxing ducks were allocated to control and heattreated groups. The ducks in the control group were kept at 25°C, and the ducks in the heat treatment group were raised at 30–40°C, which simulated the temperature change of day and night in summer. After 15 D, the intestinal contents of the duodenum, jejunum, and ileum were obtained from 6 ducks of each group. Genomic DNA was extracted and amplified based on the V4–V5 hypervariable region of 16S rRNA. The results showed that Firmicutes was the dominant bacterial phylum with the highest abundance in the contents of the small intestine of ducks, and the relative abundance of the phylum Firmicutes in all 3 intestinal segments was increased by high temperature. At the genus level, Lactobacillus was found to be the most dominant bacterial genus across 3 gut segments, and its abundance was increased in ducks under heat treatment. Compared with the corresponding intestine segment of control ducks, a total of 36 genera in the duodenum, 19 genera in the jejunum, and 6 genera in the ileum of heat-treated ducks were found to be significantly different in the abundance (linear discriminant analysis score .3.0, P, 0.05). Functional prediction of gut microbiota revealed that high temperature caused changes in the abundance of metabolism and transcription-related pathways. It is noteworthy that most of the altered pathways are related to metabolism. In conclusion, high temperature induced remarkable taxonomic changes in the gut microbiome of ducks, which might be related to the negative effects of high temperature in ducks. Our present study provided an important theoretical ground for high-temperature intervention. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed to introduce a comprehensive process for separating and recovering antimony from a complex stibnite concentrate. Antimony is first leached through a chlorination–oxidation procedure to obtain SbCl3 solution. Antimony is then recovered in the forms of cubic crystal Sb2O3 (99.9%), high-purity cathode antimony (99.98%), crude cathode antimony (99.7%), high-purity SbOCl (99.9%), and crude antimony (>99%) through the following processes: hydrolysis, membrane electrowinning, hydrolysis–low temperature smelting, and hydrolysis–washing. [Copyright &y& Elsevier]

Abstract: A systematic numerical investigation of heat transfer in turbulent channel flow over dimpled surface is conducted. Both symmetric (or spherical) and asymmetric dimple with different depth ratios (h/D) and skewness (Dx and Dz) are considered for a series of Reynolds numbers Re 2H (based on bulk velocity and full channel height) between 4000 and 6000 while Prandtl number Pr is fixed at 0.7. It is found that the optimum dimple configuration for enhancing heat transfer measured in terms of the volume goodness factor is obtained for the case of asymmetric dimple with a depth ratio of h/D =15% and stream-wise skewness of Dx =15%. The heat transfer capacity in terms of Nusselt number is significantly increased, while the associated pressure loss is kept almost to the same level as the symmetric dimple with the same depth ratio. The present study also suggests that the heat transfer enhancement is closely related to ejection with counter-rotating flow, intensified secondary flow and vortex structures at the downstream rim of asymmetric dimple. All these findings suggest that a carefully designed asymmetric dimpled surface presents a viable means of enhancing heat transfer compared to the symmetric dimple. [Copyright &y& Elsevier]

Abstract: The high temperature corrosion tests are performed on 20#steel, TP347H and superalloy C22. The high temperature corrosion behaviors of these superheater materials in the synthetic salt containing 80wt-%KCl+20wt-%K2SO4 have been investigated under the oxidizing atmosphere at a temperature of 650°C for 218hours. For comparison, the column diagram has been obtained by mass loss. The scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) is used to characterize the surface morphology and compositions of the corrosion products. The results have shown that the superalloy C22 exhibits the high corrosion resistance. [Copyright &y& Elsevier]

Abstract: Waste printed circuit boards (WPCBs) contain plenty of valuable resources and hazardous materials, considered both an attractive secondary resource and an environmental contaminant. In the current research, a hydrometallurgical process combined ammonia leaching and solvent extraction to recover copper from the metal components of WPCBs, and the production of ultrafine copper particles stripped from a solution was investigated. The results of copper oxidation leaching indicated that 96.7% of copper can be recovered at a temperature of 35°C for a leaching duration of 2h with ammonium sulfate and ammonia concentration of 2mol/L at a solid:liquid ratio of 1:10g/cm3. The treatment of leach liquor for solvent extraction of copper with LIX 84 showed that 50% LIX 84 in kerosene, a 3min period of equilibration, and a pH of 10 were sufficient for the extraction of Cu(II) and 99.6% copper can be recovered from the leached solution. The results of the preparation of copper particles from stripped solution showed that mono-dispersed ultrafine copper particles with a diameter of approximately 1.5μm were obtained from the stripped solution containing 39.25g/L Cu2+ ion, oleic acid used as surfactant, and sodium hypophosphite as reductant. As the purity of the copper extracted from the leaching system was high and the as-synthesized ultrafine copper particles possess excellent anti-oxidation property, this WPCB metal-component hydrometallurgical recycling process has the potential of recovering high-purity ultrafine copper particles. [Copyright &y& Elsevier]

Abstract: This paper made deep studies on chlorite flotation using anionic/cationic collector, and the following effect factors such as pH,Ca2+,Na2S,NaF,Na2SiF6 and (NaPO3)6 are investigated. In the process of chlorite flotation using oleic acid as anionic collector, pH value increases. The concentration increase of Na2S and NaF can activate the chlorite flotation. However, Ca2+, Na2SiF6 and (NaPO3)6 can depress the chlorite flotation. In the process of chlorite flotation using lauryl amine as cationic collector, the maximum recovery of chlorite flotation happened in neutral pH condition, and the concentration increase of Ca2+ can activate the chlorite flotation; however, NaF and Na2SiF6 can depress the chlorite flotation. [Copyright &y& Elsevier]

Abstract: An experimental research on magnetic concentrate of a hematite using the anionic reverse flotation technology in the flotation column was conducted. Through systematic studies in the lab, the optimal technological and operational conditions had been obtained as follows: the circulation pressure of 0.055 MPa, the feeding quantity of 160 g/min, the collector dosage of 800 g/t and the starch dosage of 900 g/t. The results show that the iron concentrate with grade of 67.37% can be achieved according to the flow sheet of one roughing and one scavenging under the optimal conditions, and also reflects the advantages of excellent selectivity and high recovery. The application of cyclonic static micro-bubble flotation column in hematite reverse flotation provides a new approach for hematite reverse flotation in China. [Copyright &y& Elsevier]

Abstract: Qianjiaying coke coal slime is extremely difficult to float. Conventional flotation process leads to a massive waste of high quality coal. In this paper, raw coal slime and rough separation concentrate are grinded to improve separation effect. Coal slime grinded directly through rough-cleaning process can get concentrate rate of 52.87% and concentrate ash of 11.27%. In the rough concentrate grinding process, concentrate ash drops to 10.74%, when the concentrate accumulation rate reaches up to 55.53%. Compared with the coal slime direct floatation, the concentrate rate was enhanced by 4.66%, and the ash was decreased by 1.02%. Besides, in the regrinding of middlings flotation, the concentrate rate reaches as high as 68.35% and ash rate is only 11.51%, the production efficiency is greatly improved. [Copyright &y& Elsevier]

Due to its wide wavelength coverage, multi-resolution mode, and high transmission efficiency, the wide field multi-object spectrograph becomes the most common-used universal instrument in extremely large telescopes. It's still a great challenge to build the wide field multi-object spectrograph for a 30 m class telescope because of its sharply increased volume and budget. With the rapid development of astronomy and astrophysics, the innovation of astronomical technology is fundamentally required. In this paper, the research progress of different kinds of wide-field multi-object spectrographs is illustrated and reviewed, the recent status of conceptual designs and the instrument features of the wide field multi-object spectrographs of the three 30 m class telescopes in the world, especially the current effort made by the Chinese team for the wide field multi-object spectrograph of the Thirty Meter Telescope (TMT) are introduced. [ABSTRACT FROM AUTHOR]

Abstract: One mild multiple emulsions was used for the fabrication of hollow polystyrene (PS) spheres. Polystyrene was dissolved in a volatile organic solvent to form the O phase, then an aqueous phase containing a surfactant was transferred into above phase to form an oil-in-water (Win/O) emulsion, followed by addition of Win/O emulsion in the external Wout phase, and solvent evaporation. Final product with diameter of 150μm, surface roughness of 30nm, and sphericity of 98.0% was obtained. The possible influences on the formation of PS hollow sphere were also discussed. [Copyright &y& Elsevier]

• Soil salinity negatively affected soil bacterial diversity. • The community structure in solonchak was simpler and more prone to damage. • Rare taxa were as important as abundant taxa for co-occurrence network stability. • Community assembly was gradually dominated by stochasticity as salinity increased. Soil salinization has become the most expansive form of soil degradation in arid and semiarid regions, and the management of soil salinization is imperative for achieving sustainable development. Soil microorganisms are supposed to play an integral role in controlling soil salinization, and the effects of high-salt environments on microbial community have been widely investigated, but there is currently limited comprehensive study on taxon co-occurrence patterns and assembly processes under different salt intensities. Here, based on high-throughput sequencing technologies, we analysed bacterial community structure and assembly mechanism under salt intensity in arid and semiarid regions. The results demonstrated that bacterial diversity was negatively correlated with soil salinity, and community structure also varied with changes in salt intensity. Solonchaks (soils with high soluble salt accumulation) had the lowest average degree of bacterial co-occurrence network, and there was a lower level of connectivity and correlation among bacteria in solonchaks compared to other salt-affected soils. The highest competitive connections among soil bacteria were detected in light-intensity saline soils, whereas overall collaborative connections increased with soil salinity. For co-occurrence network stability, the rare taxa (with each taxon's relative abundance < 0.1%) were more essential than the abundant taxa (> 1%). As soil salinity increased, stochastic processes gradually dominated the community assembly, and the dispersal limitation contributed from 45.18% to 58.73%. These findings offered valuable information about how soil salt intensity affected soil bacterial community and would be useful in controlling soil salinization. [ABSTRACT FROM AUTHOR]

The effects of different dietary fats with variable levels of polyunsaturated fatty acids (PUFAs) on egg quality of Shan Partridge Duck, serum, and yolk lipid parameters were examined in this study. A flock of 585 optimal produced ducks were selected and diets enriched with 0.5%, 1%, or 2% fish oil (F)/flaxseed oil (FL)/rapeseed oil (R)/tallow (T) plus basal diet were supplied through a 28-d period. Supplemental fat source and fat level had no effects on egg qualities. Proportions of yolk total cholesterol (TC), saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) were reduced (P < 0.001), while polyunsaturated fatty acids (PUFAs), ω-6 polyunsaturated fatty acids (n-6 PUFAs), ω-3 polyunsaturated fatty acids (n-3 PUFAs), Docosahexaenoic Acid (DHA), and Eicosapentaenoic Acid (EPA) were increased by fish oil, flaxseed oil, or rapeseed oil. Effects of supplementation increasing DHA and EPA were detected in F, FL, and R. Compared with C, fish oil significantly increased low-density lipoprotein cholesterol (LDL-C) in serum, flaxseed oil significantly reduced TC and increased very low-density lipoprotein cholesterol (VLDL-C), rapeseed oil significantly reduced TC and LDL-C in serum and increased VLDL-C, tallow significantly increased LDL-C. It is concluded that unsaturated fatty acids rich diets (fish oil, flaxseed oil, and rapeseed oil) might increase yolk PUFAs, reduce yolk cholesterol, and change serum lipid parameters without evident effect on egg qualities. [ABSTRACT FROM AUTHOR]

Combustion of biomass with a high content of alkali and chlorine can result in operational problems including deposition and rapid corrosion of critical components such as superheater tubes. Alloy modification is an effective way to reduce corrosion problems. Considering the excellent corrosion resistance but high cost of Ni–Cr–Mo alloy bar, the microstructure and high-temperature corrosion behaviors of the laser cladding Ni–Cr–Mo alloy coating were investigated and compared with the Ni–Cr–Mo alloy bar and the biomass boiler superheater tube material TP347H stainless steel in this study. Corrosion exposures were carried out in a tube furnace under simulated combustion gases containing 12%CO2–5%O2–0.05%HCl–N2 for 168h at 650°C and 700°C. The performance of three materials was evaluated by means of several analysis methods including: kinetic analysis (corrosion rate), SEM (microcosmic morphology of surface and cross-section),EDS (distribution of elements of cross-section) and XRD (phases formed on the surface layer). Compared to the other two materials, the overall performance was better for the laser cladding Ni–Cr–Mo alloy coating which on one hand had optimal ratio of corrosion resistance elements and on the other hand had grain strengthening effect by laser cladding technique. [ABSTRACT FROM AUTHOR]

Abstract: An interference imaging system with annular aperture is presented having focal length of 6000mm, aperture of 1000mm, and ring width/semi-diameter of 0.2. The energy analyze is carried out to evaluate the optical performance of this system, and imaging restoration processing is also performed by the blind deconvolution algorithm with iteration number of 25. Results show that the quality is close to the diffraction limit and the weight has greatly reduced to 36% of the full-aperture system, which verifies the annular aperture system is a better choice for the space telescope with large-caliber and long focal length. [Copyright &y& Elsevier]