Estimation of the flux at 1450MHz of OB stars for FAST and SKA

Radio observation is crucial to understanding the wind mechanism of OB stars but very scarce. This work estimates the flux at 1450MHz ($S_{\rm 1.4GHz}$) of about 5,000 OB stars identified by the LAMOST spectroscopic survey and confirmed by the Gaia astrometric as well as astrophysical measurements. The calculation is performed under the free-free emission mechanism for wind with the mass loss rate derived from stellar parameters. The estimated $S_{\rm 1.4GHz}$ distributes from $10^{-11}$Jy to $10^{-3}$Jy with the peak at about $10^{-8}$Jy. This implies that the complete SKA-II can detect more than half of them, and some tens of objects are detectable by FAST without considering source confusion. An array of FAST would increase the detectable sample by two orders of magnitude.Comment: 15 pages. 8 figure

Commercial Fiber Products Derived Free-Standing Porous Carbonized-Membranes for Highly Efficient Solar Steam Generation

Herein, the free-standing porous carbonized-membranes (CMs) derived from a series of commercial fiber products including airlaid papers, cellulose papers and cleanroom wipers by one-step carbonization at 160°C have for the first time explored as independent solar absorbers to realize highly efficient solar steam generation. These newly-developed CMs not only exhibit the strong absorption (low reflectance) and rapid transport of vapor/liquid, but also possess the restricted thermal diffusion. All these merits render CMs with excellent evaporation performance for solar steam generation. Particularly, the CMs derived from carbonized cellulose papers (CCPs) exhibits the best performance, which affords the water evaporation rate of 0.959 kg·m−2·h−1 and the energy conversion efficiency of 65.8% under 1 kW·m−2 solar illumination, due to the higher light absorption (92.20%) and lower thermal conductivity (0.031 W·m-1·K-1) competing favorable with those of the Au nanoparticles-loaded airlaid papers (Au-APs, 0.856 kg·m−2·h−1, 58.7%). Due to the low-cost, recyclability and highly efficient evaporation performance, the CMs, especially the CCPs, show great potential as solar absorbers for large-scale application of solar steam generation

Graphene Oxide Quantum Dots Covalently Functionalized PVDF Membrane with Significantly-Enhanced Bactericidal and Antibiofouling Performances

Covalent bonding of graphene oxide quantum dots (GOQDs) onto amino modified polyvinylidene fluoride (PVDF) membrane has generated a new type of nano-carbon functionalized membrane with significantly enhanced antibacterial and antibiofouling properties. A continuous filtration test using E. coli containing feedwater shows that the relative flux drop over GOQDs modified PVDF is 23%, which is significantly lower than those over pristine PVDF (86%) and GO-sheet modified PVDF (62%) after 10 h of filtration. The presence of GOQD coating layer effectively inactivates E. coli and S. aureus cells, and prevents the biofilm formation on the membrane surface, producing excellent antimicrobial activity and potentially antibiofouling capability, more superior than those of previously reported two-dimensional GO sheets and one-dimensional CNTs modified membranes. The distinctive antimicrobial and antibiofouling performances could be attributed to the unique structure and uniform dispersion of GOQDs, enabling the exposure of a larger fraction of active edges and facilitating the formation of oxidation stress. Furthermore, GOQDs modified membrane possesses satisfying long-term stability and durability due to the strong covalent interaction between PVDF and GOQDs. This study opens up a new synthetic avenue in the fabrication of efficient surface-functionalized polymer membranes for potential waste water treatment and biomolecules separation

Recent Advances in Elongational Flow Dominated Polymer Processing Technologies

The continuous development of plasticizing conveying methods and devices has been carried out to meet the needs of the polymer processing industry. As compared to the conventional shear-flow-dominated plasticizing and conveying techniques, a new method for processing polymers based on elongational flow was proposed. This new method and the related devices such as vane extruders, eccentric rotor extruders and so on, exhibited multiple advantages including shorter processing time, higher mixing effectiveness, improved product performance and better adaptability to various material systems. The development of new techniques in the field of polymer material processing has opened up a broad space for the development of new plastic products, improved product performance and reduced processing costs. In this review, recent advances concerning the processing techniques based on elongational flow are summarized, and the broad applications in polymer processing as well as some future opportunities and challenges in this vibrant area are elucidated in detail

Material Based Structure Design: Numerical Analysis Thermodynamic Response of Thermal Pyrolytic Graphite /Al Sandwich Composites

Amine-grafted multiwalled carbon nanotubes (MWCNTs) based thermally conductive adhesive (TCA) was studied in the previous paper and applied here in thermal pyrolytic graphite (TPG)/Al radiator due to its high thermal conductivity, toughness and cohesiveness. In this paper, in an attempt to confirm the application of TCA to TPG/Al sandwich radiator, the thermodynamic response in TPG/Al sandwich composites associated with key material properties and structural design was investigated using finite element simulation with commercial available ANSYS software. The induced thermal stress in TCA layer is substantial due to the thermal expansion mismatch between Al plate and TPG. The maximum thermal stress is located near the edge of TCA layer with the von Mises stress value of 4.02 MPa and the shear stress value of 1.66 MPa. The reasonable adjustment of physical-mechanical properties including thermal conductivity, thermal expansion, Young(,)s modulus and the thickness of TCA layer, Al plate and TPG are beneficial for reducing the temperature of the top surface of the upper skin and their effects on the reduction of thermal structural response in some ways. These findings will highlight the structural optimization of TPG/Al radiator for future application

Self-Assembled Graphene/Carbon Nanotube Hybrid Films for Supercapacitors

Stable aqueous dispersions of polymer-modified graphene sheets were prepared via in situ reduction of exfoliated graphite oxides in the presence of cationic poly(ethyleneimine) (PEI). The resultant water-soluble PEI-modified graphene sheets were then used for sequential self-assembly with acid-oxidized multiwalled carbon nanotubes, forming hybrid carbon films. These hybrid films were demonstrated to possess an interconnected network of carbon structures with well-defined nanopores to be promising for supercapacitor electrodes, exhibiting a nearly rectangular cyclic voltammogram even at an exceedingly high scan rate of 1 V/s with an average specific capacitance of 120 F/g

New insights into a first principle calculation and experimental study of SnPb-Ge ternary-metal perovskites for potential photovoltaic application

To replace Pb with a less toxic metal is a key scientific challenge because of the toxicity of Pb and the most viable replacement are Sn and Ge. In this study, we propose Sn-Pb-Ge ternary-metal perovskites CH3NH3SnxPbyGe1-x-yI3 (0< x,y < 1) for the first time. For the identification of new families, the features were verified by fist principle calculations from a theoretical perspective, especially the structural and electric performance, optical property and crystal structure. The Sn-Pb-Ge ternary-metal perovskites are prepared for from the aqueous HI/H3PO2 solvent mixture the first time, For CH3NH3Sn0.25Pb0.5Ge0.25I3, the computed results are in good agreement with the experimental data, which provide a clear-sighted insight into the design of environmentally friendly perovskites for potential electrical and tunable optical application

Photoresponsive Zinc‐Based Batteries

Photoresponsive batteries are an innovative technology that combines conversion and storage of solar energy, providing a potential solution for large‐scale utilization of solar energy while reducing the reliance on traditional energy storage devices to meet the growing demand for energy. In search of more resource‐saving alternatives to lithium‐ion batteries, researchers are turning to zinc, which is abundant and environmentally friendly due to its recyclability. Zinc batteries offer high energy density and aqueous stability, making them a popular choice among researchers. This review summarizes the recent progress in photoresponsive zinc‐based batteries. First, the photoresponsive zinc‐based batteries are categorized into two groups: photoresponsive zinc‐ion batteries and photoresponsive zinc–air batteries. The discussion then focuses on various photoelectrode designs, including some interesting strategies. Finally, the technical challenges associated with photoresponsive zinc‐based batteries are summarized and discussed, and future research directions are proposed