Solid-state color centers with manipulatable spin qubits and telecom-ranged fluorescence are ideal platforms for quantum communications and distributed quantum computations. In this work, we ...coherently control the nitrogen-vacancy (NV) center spins in silicon carbide at room temperature, in which telecom-wavelength emission is detected. We increase the NV concentration sixfold through optimization of implantation conditions. Hence, coherent control of NV center spins is achieved at room temperature, and the coherence time T2 can be reached to around 17.1 μs. Furthermore, an investigation of fluorescence properties of single NV centers shows that they are room-temperature photostable single-photon sources at telecom range. Taking advantage of technologically mature materials, the experiment demonstrates that the NV centers in silicon carbide are promising platforms for large-scale integrated quantum photonics and long-distance quantum networks.
Summary Fragmentation in social health insurance schemes is an important factor for inequitable access to health care and financial protection for people covered by different health insurance schemes ...in China. To fulfil its commitment of universal health coverage by 2020, the Chinese Government needs to prioritise addressing this issue. After analysing the situation of fragmentation, this Review summarises efforts to consolidate health insurance schemes both in China and internationally. Rural migrants, elderly people, and those with non-communicable diseases in China will greatly benefit from consolidation of the existing health insurance schemes with extended funding pools, thereby narrowing the disparities among health insurance schemes in fund level and benefit package. Political commitments, institutional innovations, and a feasible implementation plan are the major elements needed for success in consolidation. Achievement of universal health coverage in China needs systemic strategies including consolidation of the social health insurance schemes.
Abstract
Blended learning has become a popular form of teaching. In order to study a more scientific and reasonable learning plan, this paper uses CoI theory and POA theory to design the teaching ...plan. First of all, the use of POA theory output, input, output of the three stages of pre-class, in-class, after-class design respectively. The main task before class is to assign output tasks, preview the contents of the class and exchange doubts with students. In class, the teacher checks the students’ study before class. According to the students’ learning situation and output results, pertinently explain the knowledge points and summarize the information involved in the students’ independent output. Review the output according to what you have learned after class. At the same time, the corresponding teaching plans are made according to the three elements of CoI theory: social existence, teaching existence and cognitive existence. After that, it analyzes the correlation between teaching efficiency and teaching methods. The experimental results show that blended learning is better than traditional teaching methods. Finally, the optimization scheme is put forward, and the summary and prospect are carried out.
This letter presents a novel quasi-elliptic response bandpass filter (BPF) with 3 dB fractional bandwidth of 39.8% for 2.4 GHz WLAN application. Four resonant modes from two stepped-impedance stub ...loaded shorted stepped-impedance resonators (SISLSSIRs) and one dual-mode shorted stub loaded stepped-impedance resonator (SSLSIR) can constitute an asynchronously tuned coupled-resonator circuit which support a wideband performance. Four transmission zeros (TZs), i.e., one TZ due to the mixed electric and magnetic coupling, one TZ due to the harmonic effects, and another two TZs owing to the cross-couplings, are realized on both sides of the passband, resulting in its quasi-elliptic response performance. The radial stubs and high-impedance open stubs are loaded at the middle position of SISLSSIRs to improve the in-band return loss of BPF. The fabricated filter has a compact size of 0.22λ g ×0.22λ g and wide upper stopband from 2.62 to 7.69 GHz. Good agreement is shown between the simulated and measured results.
A balanced filtering rat-race coupler is proposed based on a quad-mode dielectric resonator (DR) in this brief. Due to the electromagnetic-field distributions of the DR, the desired balanced ...performance with high common-mode suppression is realized without additional circuits. Moreover, by setting the feeding probes at the proper locations, the quad-mode DR is also used to obtain the desired coupler topology with filtering responses. Accordingly, a balanced filtering rat-race coupler, integrating three circuit functions of the balanced circuit, rat-race coupler, and bandpass filter, can be designed into a single-cavity configuration, resulting in a very compact size. For verification, the proposed circuit is implemented, which shows good filtering responses, low amplitude imbalance, high common-mode suppression, and excellent phase characteristics.
For most works on constrained motion control in the literature, only constant or time-varying constraints are discussed, which are often conservative and cannot adapt to the dynamically changing ...operation environment. In this work, in the context of quadrotor operations, we propose an adaptive path following architecture with environment-aware dynamic constraints , in which the desired path coordinate, desired path speed, and constraint requirements not only depend on a path parameter associated with the desired path, but also can adapt to the presence of an "attacker" nearby. "Composite barrier function" has been proposed to address both safety and performance constraints in a unified structure. Adaptive laws are introduced to estimate the upper bounds of system uncertainties and unknown "attacker" velocity. Exponential convergence into small neighborhoods around the equilibrium for position and attitude tracking errors can be guaranteed. In the end, a simulation example further demonstrates the effectiveness of the proposed architecture.
A-to-I RNA editing catalyzed by adenosine-deaminase-acting-on-RNA (ADARs) was assumed to be unique to metazoans because fungi and plants lack ADAR homologs. However, genome-wide messenger RNA (mRNA) ...editing was found to occur specifically during sexual reproduction in filamentous ascomycetes. Because systematic characterization of adenosine/cytosine deaminase genes has implicated the involvement of
and
orthologs in A-to-I editing, in this study, we used genetic and biochemical approaches to characterize the role of
, an essential adenosine-deaminase-acting-on-tRNA (ADAT) gene, in mRNA editing in
.
had a sexual-stage-specific isoform and formed heterodimers with enzymatically inactive
. Using a repeat-induced point (RIP) mutation approach, we identified 17 mutations in
that affected mRNA editing during sexual reproduction but had no effect on transfer RNA (tRNA) editing and vegetative growth. The functional importance of the H352Y and Q375*(nonsense) mutations in sexual reproduction and mRNA editing were confirmed by introducing specific point mutations into the endogenous
allele in the wild type. An in vitro assay was developed to show that FgTad2-His proteins purified from perithecia, but not from vegetative hyphae, had mRNA editing activities. Moreover, the H352Y mutation affected the enzymatic activity of FgTad2 to edit mRNA but had no effect on its ADAT activity. We also identified proteins co-purified with FgTad2-His by mass spectrometry analysis and found that two of them have the RNA recognition motif. Taken together, genetic and biochemical data from this study demonstrated that FgTad2, an ADAT, catalyzes A-to-I mRNA editing with the stage-specific isoform and cofactors during sexual reproduction in fungi.
In this brief, miniaturized balanced-to-unbalanced (BTU) and balanced-to-balanced (BTB) filtering power dividers (FPDs) are proposed. Using one multi-mode dielectric resonator with multiple feeding ...probes, a single-cavity structure for BTU FPD is constructed, showing a compact size. Then, the circuit topology is analyzed, where the impedance in each branch can be adjusted to distribute the input power to two outputs with different ratios by only controlling the coupling coefficients. In this way, a BTU FPD with a very simple structure can be designed with arbitrary power division ratio. Besides, by replacing the two unbalanced output feeding probes in the BTU FPD as balanced ones, a BTB FPD can also be realized with controllable power division ratios. The working mechanism of the proposed designs is detailed. The proposed circuits are verified with good simulated and measured results.
Easily processed materials with the ability to transport excitons over length scales of more than 100 nanometers are highly desirable for a range of light-harvesting and optoelectronic devices. We ...describe the preparation of organic semiconducting nanofibers comprising a crystalline poly(di-
-hexylfluorene) core and a solvated, segmented corona consisting of polyethylene glycol in the center and polythiophene at the ends. These nanofibers exhibit exciton transfer from the core to the lower-energy polythiophene coronas in the end blocks, which occurs in the direction of the interchain π-π stacking with very long diffusion lengths (>200 nanometers) and a large diffusion coefficient (0.5 square centimeters per second). This is made possible by the uniform exciton energetic landscape created by the well-ordered, crystalline nanofiber core.
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•Pseudomonas aeruginosa corrosion mechanism can be explained using bioenergetics.•Starved P. aeruginosa biofilm is more corrosive than in full medium.•P. aeruginosa biofilm is grown ...to maturity before starvation starts.•Experimental data support the biocatalytic cathodic nitrate reduction theory.
This work showed that a wild-type Pseudomonas aeruginosa (PAO1) grown as a nitrate reducing bacterium biofilm on C1018 carbon steel was more corrosive under organic carbon source starvation. P. aeruginosa biofilms were pre-grown for 2days to achieve maturity before the culture media were changed to fresh culture media with 100% (as in the standard medium), 10%, and 0% organic carbons for subsequent 7-day incubation. Biofilms with 100%, 10%, and 0% organic carbons caused maximum pit depths of 5.4μm, 10.6μm, and 17.0μm, respectively. Weight loss, linear polarization resistance and electrochemical impedance spectroscopy data corroborated the pitting data.
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