Search

Magnesium (Mg)-rich primer is considered as a substitute for high polluted chromate treatment technology to provide cathodic protection for aluminum (Al) alloy. In this paper, Mg-rich primer with comprehensive properties was prepared by modifying epoxy resin using direct mixing. Specifically, the influence factors on the dispersion of Mg powder in epoxy, the modification of epoxy resin using organic silicones and the performance of Mg-modified epoxy composite coating were studied. The results show that Mg powder with small particle size has a better dispersion in epoxy; The mechanical property such as flexibility and impact resistance decreases with the addition of Mg powder, but which was improved when using modified epoxy as the resin matrix due to introduction of Si-O-Si flexible chain; In addition, the grafting efficiency between hydroxyl terminated polydimethylsiloxane and epoxy resin was improved because of the introduced silane coupling agent like KH550 contains amino group; The electrochemical test results indicate Mg-rich primer could provide effective electrochemical protection for Al alloy by raising the corrosion potential and reducing the corrosion current density to bare substrate,respectively.

The observation facts of trend and variability are estimated for a century‐long timescale, as well as some possible attributions affecting temperature extremes over Beijing‐Tianjin‐Hebei region. In this paper, the new constructed daily maximum and minimum temperature series during the last 100 years in situ stations of Beijing, Tianjin and Baoding city are used, and two 30‐year baseline climatology of 1961–1990 and 1980–2010 are both used in calculating extreme temperature events. The results indicate that there are long‐lasting, frequent and serious extreme warming over Beijing‐Tianjin‐Hebei region, especially for extreme low temperature, with larger declining trends (at 5% significance) from 1981 to 2010 baseline than those from 1961 to 1990 baseline. And from a statistical perspective, El Niño decay years and surface sea temperature (SST) anomalies at some typical ocean regions of the Arabian Sea and the Bengal Bay on the northern Indian Ocean, the Western Pacific and the Mid Atlantic, Southern Indian Ocean and around 45°–85°E, 68°–82°N on the southwest Arctic Ocean can be used as the warning signals denoting extreme warming over Beijing‐Tianjin‐Hebei region. Additionally, urbanization has a significant (at 5% significance) effect on extreme warming over Beijing‐Tianjin‐Hebei region since 1979, with 24.3% warming contribution for annual minimum temperature. [ABSTRACT FROM AUTHOR]

Summary: Poly(ethylene oxide) (PEO) polymer electrolyte has been regarded as a potential solid electrolyte which can be applied in all‐solid‐state lithium‐ion batteries (ASSLIBs). Nevertheless, low electrochemical properties and poor electrolyte/Li anode interfacial stability hinder its further application. In our work, the Li1.3Al0.3Ti1.7(PO4)3 (LATP) nanomaterials with Nasicon structure have been synthesized using a simple solvent‐thermal method, followed by being embedded into PEO polymer to form LATP filled PEO solid composite electrolytes. Effects of LATP content and particle size on electrochemical performances of solid electrolytes have been studied. By adjusting the calcination temperature, the uniformly distributed Nasicon‐type LATP powders with different sizes can be obtained. The electrochemical properties of PEO polymer electrolyte have been effectively enhanced by filling LATP nanoparticles. The composite electrolyte filled with 5 wt% LATP particles calcined at 850°C exhibits a high ionic conductivity of 5.24×10−4 S cm−1 at 55°C, which has a high electrochemical stability window of over 5 V versus Li/Li+ and a superior interfacial stability with Li metal. A LiFePO4/Li ASSLIB fabricated with the optimum composite electrolyte shows the excellent rate capability, and its discharge capacities at 0.2C, 0.5C, 1C, and 2C are 151.97, 151.56, 145.51, and 128.02 mAh·g−1. Moreover, the discharge capacity of the cell decreases from 151.69 to 130.53 mAh·g−1 after 100 charge‐discharge cycles at 0.5C rate, and the corresponding capacity retention is 86.05%. These results demonstrate that LATP nanoparticles obtained via the solvent‐thermal method are the alternative fillers for PEO polymer electrolyte. [ABSTRACT FROM AUTHOR]

A magnesium (Mg)-rich primer can provide cathodic protection for an aluminum (Al) alloy due to the lower potential of Mg. However, the Mg-rich primer prepared by simple blends shows poor flexibility and impact resistance. In this paper, bisphenol-A type epoxy resin E-20 was graft modified by hydroxyl silicon oil (HS), amino silane coupling agent and diphenyl-methane-diisocyanate (MDI) by three different ways. Then Mg-rich primer was prepared by direct blends of modified resins. Results indicate that the introduction of siloxane groups could improve the comprehensive performance of the coating especially the flexibility and impact resistance. Furthermore, Mg-rich primer prepared from MDI modified epoxy resin even possesses excellent salt spray and aging resistance. [ABSTRACT FROM AUTHOR]

Hydroxyl-containing fluoroacrylate copolymers with different fluorine and hydroxyl concentrations were synthesized via free-radical solution polymerization. Transparent fluorinated polyurethane (FPU) films were prepared by curing the copolymers with HDI (hexamethylene diisocyanate) trimer. The Fourier transform infrared spectroscopy (FT-IR) results revealed introduction of fluorine both into the copolymer and polyurethane. X-ray photoelectron spectroscopy (XPS) analyses indicated that a gradient concentration of fluorine existed in the depth profile of the fluorinated polyurethane films. The highest contact angle (CA) was obtained for the FPU film with fluoroacrylate monomer concentration of 22 wt.% because of fluorine present on the film surface. The surface topographies detected by SEM and AFM indicated that surface roughness contributed little to the film hydrophobicity. By increasing the fluoroacrylate monomer concentration, the decreasing of crosslinking degree of hard segment resulted in lowering the first degradation temperature, while more C-F groups in soft segment led to higher second degradation temperature. UV-Vis spectrophotometer measurements indicated that the FPU film with the fluoroacrylate monomer concentration of 16 wt.% still had a high transmittance of more than 90 % in the whole visible wavelength range. [ABSTRACT FROM AUTHOR]

It is well documented that the East Asian summer monsoon has been experiencing a steady weakening trend in recent decades. Because the Asian summer monsoon (including both East Asian monsoon and South Asian monsoon) is the largest and most pronounced monsoonal system in the world, its change in strength may exert a profound impact on global weather and climate systems, especially on the rainfall pattern in South and East Asia. On the other hand, as a vast elevated landmass, the Tibetan Plateau forms a huge heat source protruding into the free atmosphere. Setting against the backdrop of global climate change, whether or not does the change of this heating affect the change of Asian summer monsoon and thus rainfall distribution? Here we show that the apparent heat source over the Tibetan Plateau is closely correlated with the East Asian summer monsoonal circulation, and that the weakening of the East Asian summer monsoon is closely associated with the decreasing trend of the Tibetan Plateau apparent heat source. Further analysis indicates that the change of rainfall pattern in China in recent decades is consistent with the decreasing of the East Asian summer monsoon. [ABSTRACT FROM AUTHOR]

The dependence of particulate Langmuir-Blodgett (LB) monolayer quality on the surface nature of the substrate was investigated by pretreating the substrates with different methods, and the optimal withdrawal speed was determined by detecting the quality of particulate monolayers deposited at different withdrawal speeds. Furthermore, the effects of stearic acid (SA) concentration on the quality of particulate monolayers were discussed. Results indicated that surface amination would favor the transfer of the floating particulate monolayer from the interface to the substrate, which would be attributed to the formation of chemical bonds between the -2 groups on the substrate surface and the functional groups of - and - groups on surfaces of particles floating at the interface. And the withdrawal speed of 1 mm ⋅ min-1 was appropriate for the fabrication of high-quality particulate LB monolayer because low withdrawal speed can offer sufficient time to form chemical bonds and expel the subphase from the substrate. Additionally, SEM images illustrated that the SA concentration of 0.40 mg ⋅ mL-1 was suitable for the fabrication of well-ordered particulate LB monolayers composed by the particles of 380 nm. [ABSTRACT FROM AUTHOR]

We describe a controllable method to fabricate hexagonally close-packedLangmuir–Blodgett (LB) monolayers with stearic acid (SA) asco-surfactant and methanol as co-solvent. The optimal SA concentrationsand volume ratios of chloroform to methanol are 0.8 mg/mL and 3:1for particles of 140 nm, 0.50 mg/mL and 4:1 for particles of 300 nm,and 0.05 mg/mL and 5:1 for particles of 550 nm, respectively. Additionally,SEM detections of the monolayers transferred at different surfacepressures indicate that the monolayers deposited from the binary systemsare more compressible. The experimental results indicate that theinterparticle repulsions and particle–water interactions canbe enhanced without decreasing the particle hydrophobicity by addingSA and methanol; thus, particulate monolayers with large hexagonallyclose-packed domains composed of small silica particles can be successfullyfabricated using LB technique. We propose that the enhanced interparticlerepulsion is attributed to the Columbic repulsion resulting from theattachment of SA molecules to the CTAB modified particles around thethree phase contact line. [ABSTRACT FROM AUTHOR]

The orchid, the champagne of flowers, brings luxury, elegance, and novelty to nature. Cymbidium sinense is a symbol of gigantic floral variability on account of wavering shapes and sizes of floral organs, although marker-trait association (MTA) has not been studied for its floral traits. We evaluated markers associated with 14 floral traits of C. sinense through a genome-wide association study (GWAS) of 195 accessions. A total of 65 318 522 single-nucleotide polymorphisms (SNPs) and 3 906 176 insertion/deletion (InDel) events were identified through genotyping-by-sequencing. Among these, 4694 potential SNPs and 477 InDels were identified as MTAs at -log 10   P  > 5. The genes related to these SNPs and InDels were largely associated with floral regulators, hormonal pathways, cell division, and metabolism, playing essential roles in tailoring floral morphology. Moreover, 20 candidate SNPs/InDels linked to 11 genes were verified, 8 of which were situated on exons, one was located in the 5'-UTR and two were positioned in introns. Here, the multitepal trait-related gene RABBIT EARS ( RBE ) was found to be the most crucial gene. We analyzed the role of CsRBE in the regulation of flower-related genes via efficient transient overexpression in C. sinense protoplasts, and found that the floral homeotic genes CsAP3 and CsPI , as well as organ boundary regulators, including CsCUC and CsTCP genes, were regulated by CsRBE . Thus, we obtained key gene loci for important ornamental traits of orchids using genome-wide association analysis of populations with natural variation. The findings of this study can do a great deal to expedite orchid breeding programs for shape variability., Competing Interests: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of Nanjing Agricultural University.)

The polyethylene oxide (PEO) solid electrolyte is a promising candidate for all solid state lithium-ion batteries (ASSLIBs), but its low ionic conductivity and poor interfacial compatibility against lithium limit the rate and cycling performance of the cell. Herein, the novel and efficient TiO 2 @polydopamine (PDA) fillers have been synthesized by coating PDA onto the surface of the TiO 2 nanofibers, which are then incorporated into PEO matrices to form the composite electrolyte. The composite electrolyte displays a higher ionic conductivity of 4.36 × 10 -4 S cm -1 , a wider electrochemical window up to about 5 V and a higher t Li + of 0.190 at 55 °C compared to the PEO electrolyte. Additionally, the Li/composite electrolyte/Li batteries show a stable Li plating/stripping cycle performance, indicating good interfacial compatibility between the composite electrolyte and lithium. Thus, the LiFePO 4 /Li ASSLIBs display a fantastic rate performance and cycling stability, and deliver superior discharge specific capacities of 153.83 and 136.45 mA h g -1 at current densities of 0.5C and 2C, achieving good capacity retentions of 93.27% and 91.23% at 0.5C and 1C after 150 cycles, respectively. Therefore, the PEO-TiO 2 @PDA composite electrolyte is a potential solid electrolyte for ASSLIBs.

Accurate prediction of where and when typhoons (or named hurricanes which form over the North Atlantic Ocean) will make landfall is critical to protecting human lives and properties. Although the traditional method of typhoon track prediction based on the steering flow theory has been proven to be an effective way in most situations, it slipped up in some cases. Our analysis of the long-term Chinese typhoon records reveals that typhoons, especially super typhoons (those with maximum sustained surface winds of greater than 51 ms(-1)), have a trend to make landfalls toward warmer land in China over the past 50 years (1960-2009). Numerical sensitivity experiments using an advanced atmospheric model further confirm this finding. Our finding suggests an alternative approach to predict the landfall tracks of the most devastating typhoons in the southeastern China.