摘要 : Magnet-optical materials embracing coupled magnetic and photoluminescent properties in single phase are promising in microelectronics and optoelectronic devices. However, the current research mainly focuses on traditional inorganic materials, and there are few reports on molecule materials. Recently, we synthesized an organic–inorganic hybrid complex (C6H5C2H3FNH3)2MnCl4 (1) with perovskite structure. Physical measurements show that 1 not only behaves as an antiferromagnet with spin canting but also exhibits unusual fluorescent properties. Importantly, under the magnetic field at different temperatures, the luminous intensity of 1 changed, and a red-shift occurred with obviously optical hysteresis. These phenomena directly prove the existence of magneto-optical coupling in 1. More interestingly, the optical hysteresis can be observed in both low and high field, which is unprecedented in other molecular materials. Even in traditional inorganic materials, it can only be observed in strong field. This special function provides the possibility for the application of low energy consumption optoelectronic devices.

摘要 : Effervescence-assisted microextraction (EAM) is a novel sample pretreatment method based on the reaction of CO2 and H+ donors to generate CO2 bubbles and promote rapid dispersion of the extractant. During this process, the unique dispersion method increases the contact area between the target molecule and the extraction solvent, and the adsorption/extraction efficiency of the adsorbent/extractant toward the target molecule is also enhanced. The EAM technique is of particular interest due its convenient application, low running costs, reduced solvent consumption, high extraction efficiency, and environmental friendliness. Benefiting from the rapid development of extractants, the evolution and application of the EAM technology is becoming more tuned and diversified. Indeed, the synthesis of new extractants, such as nanomaterials with multi-pore structures, large specific surface areas, and rich active sites, has attracted extensive attention, as has the development of ionic liquids with strong extraction abilities and high selectivities. As a result, the EAM technology has been widely applied to the pretreatment of target compounds in various samples, such as food, plant, biological, and environmental samples. However, since these samples often contain polysaccharides, peptides, proteins, inorganic salts, and other interfering substrates, it is necessary to remove some of these substances prior to extraction by EAM. This is commonly achieved using methods such as vortexing, centrifugation, and dilution, among others. The treated samples can then be extracted using the EAM method prior to detection using high performance liquid chromatography (HPLC), gas chromatography (GC), and atomic absorption spectroscopy (AAS) to detect substances such as heavy metal ions, pesticide residues, endocrine-disrupting compounds (EDCs), and antibiotics. Using effervescence as a novel assisted method for the dispersion of solvents or adsorbents, the concentrations of Pb2+, Cd2+, Ni2+, Cu2+, bisphenol, estrogen, and the pyrethyl pesticides have previously been successfully determined. Moreover, many influencing factors have been evaluated during method development, including the composition of the effervescent tablet, the solution pH, the extraction temperature, the type and mass/volume of extractant, the type of eluent, the eluent concentration, the elution time, and the regeneration performance. Generally, the cumbersome single factor optimization and multi-factor optimization methods are also required to determine the optimal experimental conditions. Following determination of the optimal experimental conditions, the EAM method was validated by a series of experimental parameters including the linear range, the correlation coefficient (R2), the enrichment factor (EF), the limit of detection (LOD), and the limit of quantification (LOQ). In addition, the use of this method has been demonstrated in actual sample testing, and the obtained results have compared with those achieved using similar detection systems and methods to ultimately determine the accuracy, feasibility, and superiority of the developed method. In this paper, the construction of an EAM method based on nanomaterials, ionic liquids, and other emerging extractants is reviewed, wherein the preparation method, application range, and comparison of similar extractants were evaluated for the same extraction system. In addition, the current state-of-the-art in relation to EAM research and application when combined with HPLC, cold flame AAS, and other analytical techniques is summarized in terms of the detection of harmful substances in complex matrices. More specifically, the samples evaluated herein include dairy products, honey, beverages, surface water, vegetables, blood, urine, liver, and complex botanicals. Furthermore, issues related to the application of this technology are analyzed, and its future development trend in the field of microextraction is forecasted. Finally, the application prospects of EAM in the analysis of various pollutants and components are proposed to provide reference for monitoring pollutants in food, environmental, and biological samples.

摘要 : ObjectiveDue to the influence of the processing error of optical elements, system assembly error, and ambient temperature, the optical system usually has static aberrations, which reduce the imaging quality and significantly affects the optical performance. The stochastic parallel gradient descent (SPGD) algorithm is widely used to correct static aberrations. For the SPGD algorithm, the performance metrics, usually including the Strehl ratio (SR), encircled energy (EE), and mean radius (MR), have a great influence on the correction accuracy. In practical applications, SR is seldom chosen as it is difficult to achieve. In terms of EE, the convergence speed and correction accuracy depend closely on the selected encircled area, and hence, EE can only represent the total energy distribution of the surrounding area but cannot effectively reflect the entire intensity distribution. In contrast, the performance metric MR takes the whole intensity distribution into consideration, and higher correction accuracy is thus obtained. However, it is sensitive to small disturbance voltage, which makes the correction unstable. Therefore, to achieve high-precision and stable correction of static aberrations, we propose a combination method of performance metrics, which can not only concentrate the spot energy but also make the energy distribution uniform.MethodsThe proposed method combines the performance metrics EE and MR to correct the static aberrations. EE is first chosen as the performance metric and is computed with the acquired image. The control voltage is calculated and applied on the deformable mirror to correct the distorted wavefront. When most of the energy is concentrated in the encircled area, the performance metric is switched from EE to MR. Afterward, the energy distribution is further unified, which can also reduce the MR of the light spot. Thus, with the combination method, the energy can be better concentrated, and the intensity distribution can be more uniform. Meanwhile, the static aberrations can be corrected with higher accuracy.Results and DiscussionsFirst, to concentrate the energy at the center of the image plane, we use EE for correction. After the energy is concentrated, it is then corrected with MR so that the energy distribution can be more uniform (Fig. 3). EE, MR, and the combination method of performance metrics are simulated and compared to verify the effectiveness of the proposed method (Fig. 12), and the root-mean-square values of residual aberrations are 0.22λ, 0.43λ, and 0.01λ, respectively. Compared with the EE and MR methods, the combination method can achieve better spot image quality and dramatically increased peak intensity. In addition, the corresponding SRs are computed to be 0.53, 0.78, and 1.00, respectively. Moreover, the simulations of the correction results based on the three methods under different noises (Fig. 14), different encircled diameters (Fig. 15), and multiple random static aberrations (Fig. 16) are compared and analyzed. For the combination method, SR remains stable at 1.00 after correction. Finally, an experiment is performed to further validate the proposed method. As a result, the corrected resolutions are improved to be 2.15, 1.40, and 1.05 times the diffraction limit for the three methods, respectively, and in particular, the diffraction limit of the optical system is almost achieved with the combination method (Fig. 18). The research reveals that the proposed method can realize higher correction accuracy and stability.ConclusionsThe combination method of performance metrics proposed in this paper can effectively improve the correction accuracy and stability of static aberrations. Simulations show that the SR corrected by the combination method can keep stable at 1.00 under different encircled diameters, different noises, and multiple static aberrations. As further demonstrated by experiments, with the combination method, the light spot is the most focused, and the resolution is improved to be 1.05 times the diffraction limit. Both the experimental results and simulations confirm the effectiveness of the proposed method in static aberration correction. The method provides a facile and effective way for the correction and elimination of static aberrations in optical systems with optical performance close to the diffraction limit.

摘要 : In this paper, we discuss the circumradius of reduced convex polygons and Reuleaux polygons. We prove that from amongst all reduced convex n-gons of a fixed thickness, only the regular n-gon has the minimal circumradius. For Reuleaux polygons, we show that from amongst all n-th Reuleaux polygons, only the regular n-th Reuleaux polygon has the minimal circumradius.

摘要 : A stable partial nitritation process that was achieved by treating activated sludge in sidestream with formate as a selective inhibitor has been previously described. However, little is known about the effect of formate on the microbial communities in both the partial nitritation and the subsequent anammox process. To this end, a formate sidestream-mediated partial nitritation-coupled anammox process was established and studied. The effluent ratio of nitrite/ammonia in the partial nitritation remained at 1.24 ± 0.19, and the total nitrogen removal efficiency of the anammox process was maintained at 80.0 ± 1.6%. Metagenomic and metatranscriptomic analysis showed that the nitrite oxidizing bacteria (NOB) was almost eliminated from the partial nitritation process, while Nitrosomonas europaea was the dominant ammonia-oxidizing bacteria (AOB) with an abundance of 30.8% of total reads. The high expression of nitrous oxide reductase genes in the partial nitritation process suggested a great potential for mitigating nitrous oxide release. Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia sinica were identified as the main anammox bacteria, and their abundances were as high as 49.3 and 11.8%, respectively. There was a highly expressed gene encoding a formate tetrahydrofolate ligase in the Candidatus Kuenenia stuttgartiensis metagenome-assembled genomes (MAG), suggesting that formate-related metabolic activity may contribute to its enrichment in the anammox process.

摘要 : Thermally activated delayed fluorescence (TADF) materials with aggregation-induced emission (AIE) features can overcome aggregation-caused quenching (ACQ) and emit intensely in aggregate states and thus have attracted enormous attention in the fields of high-efficiency organic light-emitting diodes, bioimaging, photodynamic therapy, photocatalysis, etc. However, their corresponding exact working mechanisms at the microscopic level are still far from clear. Herein, by carefully investigating the physical properties of our newly designed TADF material 6-(10H-spiro[acridine-9, 9′-fluoren]-10-yl)nicotinonitrile in various states, we concluded that conformational isomerization plays an important role in realizing high photoluminescence quantum yields in its amorphous neat film state, in which the high-lying quasi-axial conformations with non-TADF features and low-lying quasi-equal conformations with TADF characteristics serve as the host matrix and dopant, respectively, thus suppressing ACQ in disordered aggregate states. Our work not only offers a new possible microscopic mechanism by using conformational isomerization for the AIE-TADF phenomenon but also provides a novel method for designing high-efficiency AIE-TADF emitters.

摘要 : In nanoparticle imaging, particle clusters and large impurity particles in the defocused position cause bright spots, thus hindering the existing focusing algorithms in realizing the autofocus function. This study used binarization segmentation based on the Otsu algorithm, as well as morphological opening and closing methods, to aggregate the dispersed diffuse spots into one area. Furthermore, the connected domain labeling method was used to filter out large regions of the spot area. A four-neighborhood level-diagonal square function and threshold-four-neighborhood level-diagonal square root function were constructed and used as the evaluation indicators for the coarse and fine focus, respectively, thereby improving the accuracy and reliability of autofocus search. The defocus sequence diagram was obtained and the proposed algorithm was compared to the five commonly used evaluation algorithms. The results demonstrate that the proposed autofocus evaluation algorithm is highly robust, unbiased, and unimodal.

摘要 : Surface Plasmon Polaritons(SPPs) is a kind of electromagnetic wave propagating along the interface between metal and dielectric. SPPs has the property of confining electromagnetic wave energy in half wavelength region, which can break through the diffraction limit in traditional optics, and is widely used in the design of subwavelength optical devices. In this paper, the Metal-Insulator-Metal (MIM) structure is chosen to excite SPPs. The MIM structure has a wide spectrum range, supports high group-speed modes at subwavelengths, and enables accurate optical regulation over long distances propagation. In this paper, a MIM waveguide filter based on anchor resonator is designed, the structure is simulated, and the transmission characteristics are analyzed. The simulation results show that the filtering effect at the resonance wavelength changes significantly with the changes of the arc structure angle θ, the rectangular structure height H and the arc structure radius R, and the filtering effect can be precisely controlled by adjusting the corresponding relationship between the parameters fitting data. Because SPPs is sensitive to the refractive index of the medium in the resonator, it can be used to design the refractive index sensor if the anchor resonator is filled with different mediums. In order to explore the influence of structural parameters on waveguide transmission characteristics and further optimize the filter structure, the structural parameters θ, H and R are analyzed, the transmission curve skewing caused by the change of structural parameters is discussed, and the factors leading to the spectral line red shift are expounded. Using the fitting results, high performance narrow band band-stop filters with specific wavelength can be designed. Narrow band band-stop filter is designed based on three windows of multimode fiber. The performance of the three communvication window filters is superior, and the performance is significantly improved compared with other MIM filters. When filtering one window, the normal transmission of the other two windows will not be affected. The communication window selection regulation in optical communication is realized. The sensitivity of the resonance wavelength λr to the refractive index n of the medium in the anchor resonator is studied. The simulation results show that with the increase of the refractive index n, the resonant wavelength of each mode is red shifted and the transmission curve is changed. The SPPs coupling in MIM structure is sensitive to the refractive index of the medium in anchor resonator, which can be used to make sensing equipment. Compared with the MIM structure of L-shaped resonator, the sensitivity is improved and it is more suitable for designing medium refractive index sensor. In conclusion, a filter based on anchor resonator is designed in this paper. Simulation analysis shows that the structure parameters θ, H and R of anchor resonator can affect its filtering effect, and the narrow band band-stop filtering under the communication window is realized. When the anchor resonator is filled with different mediums, the red shift of transmission spectrum is caused by the increase of refractive index, which provides a theoretical basis for the design of simple dielectric refractive index sensor by using anchor resonator.

摘要 : Porous layered g-C3N4 was selected as base material via direct calcination method to synthesize g-C3N4/CeO2/BiOBr ternary composite photocatalytic materials with heterogeneous structure, while CeO2/BiOBr composites were introduced by ultrasonic stirring method. The composition, structure and optical properties of g-C3N4/CeO2/BiOBr were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis DRS and photoluminescence analysis, and so on. The results show that the g-C3N4/CeO2/BiOBr has sandwich layered stacking structure, good interface contact structure and excellent light response performance due to the uniform phase distribution and high degree of crystallization. When the molar fraction of Ce∶Bi is 1∶1 and the mass fraction of g-C3N4 is 15%, the obtained three-phase composite shows the highest photocatalytic degradation property for RhB. The degradation rate for RhB is 99%, which is 86 times that of pure CeO2 and 3 times that of pure BiOBr. In addition, the composite has good stability with the RhB degradation efficiency of 89% after four cycles.

摘要 : The decoherence of temporal quantum correlation is explored in a voltage-controlled quantum dots molecule coupled to a cavity. The temporal correlation in the optoelectronic hybrid system is studied based on Leggett-Garg inequalities. The inequality violations can be interpreted as the existence of temporal quantum correlation during dynamical evolution. The temporal quantum correlation is enhanced by its electron tunnel's strength and cavity frequency detuning. It is found that there is no temporal quantum correlation in the regions where the values of spatial quantum correlation are zero and the maximal violations occur in conditions with high values of quantum correlation. In contrast, the spatial quantum coherence can still exsit when the value of temporal quantum correlation is zero. The method of open quantum system dynamic is used to study the effect of reservoir memory on temporal quantum correlation. The temporal quantum correlation can be suppressed due to the spontaneous decay of the quantum dots and cavity leakage. These results are helpful for quantum information processing technology in hybrid quantum systems.