Photoelectrochemical (PEC) cathodic protection is considered as an environment friendly method for metals anticorrosion. In this technology, a n-type semiconductor photoanode provides the ...photogenerated electrons for metal to achieve cathodic protection. Comparing with traditional PEC photoanode for water splitting, it requires the photoanode providing a suitable cathodic potential for the metal, instead of pursuit ultimate photon to electric conversion efficiency, thus it is a more possible PEC technology for engineering application. To date, great efforts have been devoted to developing novel n-type semiconductors and advanced modification method to improve the performance on PEC cathodic protection metals. Herein, recent progresses in this field are summarized. We highlight the fabrication process of PEC cathodic protection thin film, various nanostructure controlling, doping, compositing methods and their operation mechanism. Finally, the current challenges and future potential works on improving the PEC cathodic protection performance are discussed.
Display omitted
Polylactide (PLA)/polyvinylidene fluoride (PVDF) hybrid dielectrics with high melt flow index ratio have been prepared by a novel twin-eccentric rotor extruder (TERE). In TERE, the continuous ...elongational flow, originated from the alternate compression and release, plays a key role during melt blending. Compared to traditional shear flow, it facilitates the dispersion and orientation of the dispersed phase along the elongational direction, forming the fine and anisotropic micromorphology in PLA/PVDF blends. With the change of composition ratio, twice phase transitions and three structure regions are observed, in which the interpenetrating network structure is formed at 60-70 wt% PVDF loading. Based on the coupling effect of elongational flow and material properties, the mechanism of microstructure evolution for PLA/PVDF blends is put forward. In addition, the effective dielectric constant of PLA/PVDF blends is slowly and then rapidly improved in linear with PVDF content increasing. The turning point is the first phase transition due to the formation of new continuous phase of PVDF.
Display omitted
•The new novel twin-eccentric rotor extruder (TERE) self-designed is dominated by continuous elongation flow.•PLA/PVDF hybrid dielectrics prepared by TERE has a fine, uniform and anisotropic micromorphology.•The mechanism of microstructure evolution is based on the coupling effect of elongational flow and material properties.•The turning point of effective dielectric constant of PLA/PVDF blends appears at the first phase transition.
Abstract
Despite the fact that the progenitor of fast blue optical transients (FBOTs) is still a subject of debate, FBOTs are sometimes suggested to originate from the core collapse of ultra-stripped ...stars and be powered by a spinning-down neutron star. Following this consideration, it is expected that the late-time evolution of the progenitor stars can leave important imprints in the circumstellar material (CSM) of FBOTs, due to the strong mass loss of the stars. The interaction of the FBOT ejecta with the CSM can drive a long-lasting shock to generate radio emission, which thus enables us to probe the CSM properties through radio observation although such observations are still rare. Within the framework of the magnetar-powered model, Liu et al. fitted the multi-band optical light curves of 40 FBOTs, and hence, the statistical distributions of the FBOT magnetar and ejecta parameters were obtained. Based on these FBOT population results, we investigate the dependence of the radio emission on the mass-loss rate of the progenitors and evaluate the detectability of radio emission from FBOTs with current and future telescopes. It is found that the distribution of the peak time and peak luminosity of the emission at 8.4 GHz are primarily in the regions of
t
peak,
ν
= 10
2.12±0.63
days and
L
peak,
ν
= 10
28.73±0.83
erg s
−1
Hz
−1
, respectively. A joint detection of the Zwicky Transient Facility and Very Large Array could achieve success in about 8.7% FBOTs of
z
≤ 1. Furthermore, if considering a joint detection of the Chinese Space Station Telescope and the Square Kilometer Array, this rate of success could be increased to about 23.9%.
Pathogenic bacterial membrane proteins (MPs) are a class of vaccine and antibiotic development targets with widespread clinical application. However, the inherent hydrophobicity of MPs poses a ...challenge to fold correctly in living cells. Herein, we present a comprehensive method to improve the soluble form of MP antigen by rationally designing multi‐epitope chimeric antigen (ChA) and screening two classes of protein‐assisting folding element. The study uses a homologous protein antigen as a functional scaffold to generate a ChA possessing four epitopes from transferrin‐binding protein A of Glaesserella parasuis. Our engineered strain, which co‐expresses P17 tagged‐ChA and endogenous chaperones groEL‐ES, yields a 0.346 g/L highly soluble ChA with the property of HPS‐positive serum reaction. Moreover, the protein titer of ChA reaches 4.27 g/L with >90% soluble proportion in 5‐L bioreactor, which is the highest titer reported so far. The results highlight a timely approach to design and improve the soluble expression of MP antigen in industrially viable applications.
Chen et al. present a novel strategy to improve soluble form of multi‐epitope chimeric antigen via computer‐assisted strategy and folding elements is developed in this study, which provides potential applications to achieve high soluble expression and productivity of membrane protein antigen against Glaesserella parasuis. By using this strategy, an industrial E. coli recombinant strain capable of efficiently expressing subunit vaccine candidate was obtained.
This paper reports an efficient dissolution and modification strategy for fabricating robust and durable F-PE/SiO2 foam, which could maintain its superhydrophobicity under 980 Pa dynamic pressure of ...water droplet impacting and 8.1 kPa pressure of water flow impacting. Besides robust dynamic superhydrophobicity, the F-PE/SiO2 foam exhibit exceptional mechanical durability against knife scratching, tape-peeling, bending-twisting, and ultrasonication in ethanol. Impressively, the foam maintains superhydrophobicity upon abrasion damage until all the thickness is worn away.
Display omitted
•Superhydrophobic foam is fabricated via dissolution and modification method.•The prepared foam feature exceptional dynamic robustness and mechanical durability.•The superhydrophobicity is retained upon abrasion until all the thickness is lost.•The superhydrophobic foam exhibits excellence in self-cleaning and anti-icing.
The poor robustness and durability of superhydrophobic surfaces under various externally imposed stresses have become a challenging issue for practical applications. Here, an efficient dissolution and modification strategy is proposed for facilely fabricating superhydrophobic polyethylene (F-PE/SiO2) foam with 98.6% porosity using sodium chloride (NaCl) as a sacrificial template and superhydrophobic nano-silica particles as a surface chemical modifier. A microscale porous and interconnected 3D framework is formed when NaCl is dissolved and the nano-silica particles adsorb on the surface of interconnected pores to form nanoscale structures. The F-PE/SiO2 foam exhibits a water contact angle (CA) of 158 ± 2° and a sliding angle (SA) of 4 ± 2°. Interestingly, the F-PE/SiO2 foam could maintain its superhydrophobicity under 980 Pa pressure of water droplet impacting and 8.1 kPa pressure of water flow impacting. Besides robust dynamic superhydrophobicity, the F-PE/SiO2 foam exhibits exceptional mechanical durability against knife scratching, tape-peeling, bending-twisting, and ultrasonication in ethanol because of unique hierarchical micro-nanostructure and the stably adsorbed nano-silica particles. Impressively, the F-PE/SiO2 foam maintains superhydrophobicity upon abrasion damage until all the thickness is worn away, which are potentially advantageous in practical applications. Moreover, this F-PE/SiO2 foam also demonstrated excellence in anti-wetting, self-cleaning and anti-icing, which makes the product can effectively reduce the damage caused by surface pollution, ice formation, and other natural factors when applied to oil-water separation and insulation material of refrigerator.
Abstract
Gamma-ray bursts (GRBs) have been phenomenologically divided into long- and short-duration populations, generally corresponding to collapsar and compact merger origins, respectively. Here, ...we collect three unique bursts, GRBs 060614, 211211A, and 211227A, all of which are characterized by a long-duration main emission (ME) phase and a rebrightening extended emission (EE) phase, to study their observed properties and their potential origins as neutron star–black hole (NSBH) mergers. NS-first-born (BH-first-born) NSBH mergers tend to contain fast-spinning (nonspinning) BHs that more easily (hardly) allow tidal disruption to occur, while (without) forming electromagnetic signals. We find that NS-first-born NSBH mergers can well interpret the origins of these three GRBs, supported by the following. (1) Their X-ray MEs and EEs show unambiguous fallback accretion signatures, decreasing as ∝
t
−5/3
, which might account for their long durations. The EEs could result from the fallback accretion of
r
-process heating materials, which is predicted to occur after NSBH mergers. (2) The beaming-corrected local event-rate density for these types of merger-origin long-duration GRBs is
0
∼
2.4
−
1.3
+
2.3
Gpc
−
3
yr
−
1
, consistent with that of NS-first-born NSBH mergers. (3) Our detailed analysis of the EE, afterglow, and kilonova of the recent high-impact event GRB 211211A reveals that it could be a merger between a
∼
1.23
−
0.07
+
0.06
M
⊙
NS and a
∼
8.21
−
0.75
+
0.77
M
⊙
BH, with an aligned spin of
χ
BH
∼
0.62
−
0.07
+
0.06
, supporting an NS-first-born NSBH formation channel. A long-duration burst, with a rebrightening fallback accretion signature after the ME, and a bright kilonova, might be commonly observed features for on-axis NSBH mergers. We estimate the multimessenger detection rate between gravitational waves, GRBs, and kilonova emissions from NSBH mergers in O4 (O5) to be ∼0.1 yr
−1
(∼1 yr
−1
).
Conductive polymer composites with segregated structure (s‐CPCs) are widely used in the electronics industry. Achieving selective distribution of the conductive fillers in the polymer matrix is an ...effective way to construct s‐CPCs. In this work, the starch was used as the matrix and the carbon nanotube (CNT) was used as the conductive fillers to fabricate multifunctional s‐CPCs, via simple mechanical mixing and compression molding. During the processing, the starch underwent partial gelatinization, which was conducive to the fusion of the starch granules and the selective distribution of the CNT. Scanning electron microscope and atomic force microscope images showed that the CNT was attached to the surface of the starch granules to form a segregated structure. The starch/CNT composites exhibited a significant percolation, with a percolation threshold of 0.24 vol%. When the CNT content was 3.05 vol%, the starch/CNT composites exhibited a high electromagnetic interference (EMI) shielding effectiveness of 33.12 dB, which was commercially applicable in EMI shielding devices. The starch/CNT composites also possess good thermal management properties and can be used as thermal conductors and electro‐thermal conversion devices. This work manifests the application prospect in the field of the electronics industry and broadens the application potential of starch.
Abstract
White dwarfs (WDs) embedded in the gaseous disks of active galactic nuclei (AGNs) can rapidly accrete materials from these disks and grow in mass to reach, or even exceed, the Chandrasekhar ...limit. Binary WD (BWD) mergers are also believed to occur in AGN accretion disks. We study observational signatures from these events. We suggest that mass-accreting WDs and BWD mergers in AGN disks can lead to thermonuclear explosions that drive an ejecta shock breakout from the disk surface and power a slow-rising, relatively dim Type Ia supernova (SN). It is possible that such SNe Ia may be outshone by the emission of the AGN disk around a supermassive black hole (BH) with a mass of
M
SMBH
≳ 10
8
M
⊙
. In addition, accretion-induced collapses (AICs) of WDs in AGN disks may sometimes occur, which may form highly magnetized millisecond neutron stars (NSs). The subsequent spindown process of this nascent magnetar can deposit its rotational energy into the disk materials, resulting in a magnetar-driven shock breakout and a luminous magnetar-powered transient. We show that such an AIC event could power a rapidly evolving and luminous transient for a magnetic field of
B
∼ 10
15
G. The rising time and peak luminosity of the transient, powered by a magnetar with
B
∼ 10
14
G, are predicted to have similar properties to those of superluminous SNe. AIC events taking place in the inner parts of disks around relatively less massive supermassive BHs (
M
SMBH
≲ 10
8
M
⊙
) are more likely to power transients that are much brighter than the AGN disk emission, and hence easily identified.
In this work, we fabricate a novel bismuth vanadate/two dimensional-carbon nitride/deoxyribonucleic acid (BiVO4/2D-C3N4/DNA) aptamer photoelectrochemical (PEC) sensor, and this sensor provides a ...record detection sensitivity area (5 × 10−7 μg/L - 10 μg/L) for Microcystin-LR (MC-LR). Meanwhile, except for MC-LR detection, this sensor presents highly sensitivity for tumor marker, heavy metal ion, antibiotic also by changing the DNA aptamer. Photo charge dynamic and theory calculation results reveal that 2D-C3N4 is a key material for multifunctional interface reconciliation of this PEC aptamer sensor. Firstly, it can serve as photogenerated hole oriented-transfer medium from the BiVO4 photoanode to the detective target; In addition, 2D-C3N4 with large area of π electron cloud can fix the DNA aptamer parallelly by π-π bonding with the nucleic acid in the DNA aptamer to shorten the hole transfer distance from the semiconductor to target. So that, a record MC-LR detection sensitivity has been achieved by the 2D-C3N4 modified BiVO4/DNA aptamer sensor.
Display omitted
•Novel PEC BiVO4/2D-C3N4/DNA aptamer sensor has been fabricated.•Record sensitivity for Microcystin-LR detection.•2D-C3N4 provides a multifunctional reconciliation of the BiVO4/DNA interface.•The sensor shows large application width for trace substances detection.
PDF
