A Ku and Ka dual bands feed based on dielectric loaded corrugated horn is proposed in this paper. The dual bands signals are fed and transmitted by a coaxial feeding network and radiated by a dielectric loaded corrugated horn. Based on body of revolution finite difference time domain and optimization algorithm, the feed is simulated and optimized. A prototype of the feed is fabricated and measured. The measured and calculated performances are in good agreement. The relative bandwidths in Ku/Ka dual bands reach 27.9 % and 45.1%, respectively. The calculated aperture efficiency in dual bands is greater than 65% by feeding the 7.3m ring focus antenna, which meets the design requirements.
Abstract The [3 + 3] cylcloaddition/annulation is an important complementary for construction of six‐membered ring. With addition of organophosphine to the Morita‐Baylis‐Hillman (MBH) carbonate, a potential C3 synthon can be furnished. In this work, the catalytic mechanisms for using this synthon as the nucleophilic or electrophilic dipole to react with the cyclohexa‐2,5‐dienone‐substituted benzenesulfonamide are studied by the density functional theory method. The computational results reveal that the nucleophilic addition of the amide anion to the allylic phosphonium is more favorable than the electrophilic addition of alkenyl in the benzenesulfonamide with the allylic phosphorus ylide. Namely, the allylic phosphonium adduct, rather than the allylic phosphorus ylide that is generated by deprotonation of the allylic phosphonium, is more likely to act as the potential dipole. The global reactivity index calculations indicate that species involved in the favored pathway have better reactivities (both in nucleophilicity and electrophilicity), especially the significantly higher nucleophilicity of the amide anion.
Clubroot disease poses a significant threat to Brassica crops, necessitating ongoing updates on resistance gene sources. In F 2 segregants of the clubroot-resistant inbred line BrT18-6-4-3 and susceptible DH line Y510, the genetic analysis identified a single dominant gene responsible for clubroot resistance. Through bulk segregant sequencing analysis and kompetitive allele-specific polymerase chain reaction assays, CRA8.1.6 was mapped within 110 kb (12,255–12,365 Mb) between markers L-CR11 and L-CR12 on chromosome A08. We identified B raA08g015220.3.5C as the candidate gene of CRA8.1.6 . Upon comparison with the sequence of disease-resistant material BrT18-6-4-3, we found 249 single-nucleotide polymorphisms, seven insertions, six deletions, and a long terminal repeat (LTR) retrotransposon (5,310 bp) at 909 bp of the first intron. However, the LTR retrotransposon was absent in the coding sequence of the susceptible DH line Y510. Given the presence of a non-functional LTR insertion in other materials, it showed that the LTR insertion might not be associated with susceptibility. Sequence alignment analysis revealed that the fourth exon of the susceptible line harbored two deletions and an insertion, resulting in a frameshift mutation at 8,551 bp, leading to translation termination at the leucine-rich repeat domain’s C-terminal in susceptible material. Sequence alignment of the CDS revealed a 99.4% similarity to Crr1a , which indicate that CRA8.1.6 is likely an allele of the Crr1a gene. Two functional markers, CRA08-InDel and CRA08-KASP1, have been developed for marker-assisted selection in CR turnip cultivars. Our findings could facilitate the development of clubroot-resistance turnip cultivars through marker-assisted selection.
The facile preparation, characterization, and application of novel dual-shell TpBD (a kind of covalent-organic framework) coated magnetic nanospheres as sorbents for simple, fast, and high selectivity capture of 14 heterocyclic aromatic amines (HAAs) are reported. Quantum chemistry theory calculations were conducted to directly and quantifiably describe the multiple interactions, including π-π, hydrogen bonding, cation-π, static electricity, and ion-exchange, between TpBD and heterocyclic aromatic amines. The excellent adsorption capacity of TpBD coated magnetic nanospheres was further evaluated by extraction of 14 HAAs from nonsmokers' and smokers' urine samples. Under the optimized conditions, the magnetic solid phase extraction process can be completed with high recovery ranging from 95.4% to 129.3%. After being washed with acetonitrile and water successively, the collected sorbents can be easily recycled and reused five times without any significant difference in performance. Coupled with the ultra performance liquid chromatography-tandem mass spectrometer detection, the exposure level of HAAs in nonsmokers and smokers smoking cigarettes with different tar yields were successfully explored. And, this implied that the robust method based on the versatile TpBD coated dual-shell magnetic nanospheres sorbents represents a great potential application in the analysis of disease markers and body fluids.
The development of sustainable synthesis route to produce functional and bioactive polymer colloids has attracted much attention. Most strategies are based on the polymerization of monomers or crosslinking of prepolymers by enzyme‐ or cell‐mediated reactions or specific catalysts in confined emulsions. Herein, a facile solution spray method was developed for spontaneous synthesis of microgels without use of confined emulsion, additional initiators/catalysts and deoxygenation, which addresses the challenges in traditional microgel synthesis. The polarization of air‐water interface of the microdroplets can spontaneously split hydroxide ions in water to produce hydroxyl radicals, thereby initiating polymerization and crosslinking in air environment. This synthesis strategy is applicable to a variety of monomers and enables the fabrication of microgels with tunable chemical structures and variable sizes. Importantly, the synthesis route also allows for the preparation of enzyme‐ or drug‐loaded microgels via the in‐situ encapsulation, which also display high enzymatic activity and stimuli‐triggered drug release. Therefore, this work not only is of great significance to macromolecular science and microdroplet chemistry, but also may bring new insights into cellular biochemistry and even prebiotic chemistry due to the prevalence of microdroplets in the environment.
mostly in computer science and engineering, were generated by the SCIgen computer program and were all published between 2006-2018.Immediately after receiving the alert, Atlantis
Abstract Water‐borne phosphine‐functionalized core‐cross‐linked micelles ( CCM ) consisting of a hydrophobic core and a hydrophilic shell were obtained as stable latexes by reversible addition–fragmentation chain transfer (RAFT) in water in a one‐pot, three‐step process. Initial homogeneous aqueous‐phase copolymerization of methacrylic acid (MAA) and poly(ethylene oxide) methyl ether methacrylate (PEOMA) is followed by copolymerization of styrene (S) and 4‐diphenylphosphinostyrene (DPPS), yielding P(MAA‐ co ‐PEOMA)‐ b ‐P(S‐ co ‐DPPS) amphiphilic block copolymer micelles ( M ) by polymerization‐induced self‐assembly (PISA), and final micellar cross‐linking with a mixture of S and diethylene glycol dimethacrylate. The CCM were characterized by dynamic light scattering and NMR spectroscopy to evaluate size, dispersity, stability, and the swelling ability of various organic substrates. Coordination of [Rh(acac)(CO) 2 ] (acac=acetylacetonate) to the core‐confined phosphine groups was rapid and quantitative. The CCM and M latexes were then used, in combination with [Rh(acac)(CO) 2 ], to catalyze the aqueous biphasic hydroformylation of 1‐octene, in which they showed high activity, recyclability, protection of the activated Rh center by the polymer scaffold, and low Rh leaching. The CCM latex gave slightly lower catalytic activity but significantly less Rh leaching than the M latex. A control experiment conducted in the presence of the sulfoxantphos ligand pointed to the action of the CCM as catalytic nanoreactors with substrate and product transport into and out of the polymer core, rather than as a surfactant in interfacial catalysis.
Comprehensive Summary The privileged C 2 ‐symmetric rigid phenol‐type ligand is more attractive but challenging in asymmetric catalysis. Herein, we designed and synthesized a class of rigid‐featured chiral tridentate Phenol‐2NO ligands, that incorporate the advantages of both the phenol skeleton and pyrroloimidazolone‐based N ‐oxide moiety, from readily available L ‐prolinamides in operationally simple two steps and up to 44% overall yield. More importantly, using an achiral quinoline derivative as an additive, the newly developed Phenol‐2NO ligand could serve as the anioic ligand upon deprotonative activation to coordinate to Zn(II) to form a highly enantioselective catalyst for the asymmetric Michael‐type Friedel‐Crafts alkylation reaction of indoles with 2,3‐dioxopyrrolidines. Excellent yields (up to 90%) and high enantioselectivities (up to 99% ee) are obtained for a wide range of substrates under mild conditions. Experiments and DFT calculations revealed the reaction mechanism and the origins of the enantioselectivity. This also represented the first activation of phenol‐type ligand/metal complex by an achiral organic base as the additive in asymmetric catalysis.
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