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Optical vortices (OVs), as eigenmodes of optical orbital angular momentum, have been widely used in particle micro-manipulation. Recently, perfect optical vortices (POVs), a subclass of OVs, are gaining increasing interest and becoming an indispensable tool in optical trapping due to their unique property of topological charge-independent vortex radius. Here, we expand the concept of POVs by proposing concentric ring optical traps (CROTs) and apply them to trapping and rotating particles. A CROT consists of a series of concentric rings, each being a vortex whose radius and topological charge can be controlled independently with respect to the other rings. Quantitative results show that the generated CROTs have weak sidelobes, good uniformity, and relatively high diffraction efficiency. In experiments, CROTs are observed to trap multiple dielectric particles simultaneously on different rings and rotate these particles with the direction and speed of rotation depending on the topological charge sign and value of each individual ring. In addition, gold particles are observed to be trapped and rotate in the dark region between two bright rings. As a novel tool, CROTs may find potential applications in fields like optical manipulation and microfluidic viscosity measurements.

This paper introduces the latest research on the application of the new dynamic network DEA method in the measurement of the operating efficiency of the banking industry, and measures the operating efficiency of 15 listed banks in China by using the directional distance function (DDF) and the new dynamic network DEA model combined with the Malmquist index. To effectively evaluate the impact of uncertain financial risks on the operating efficiency of banks, we respectively selected the measurement indicators of total assets, number of employees, deposits, and net profit to calculate the operating efficiency of banks in the process of medium and long-term investment. According to the actual situation of bank operation, the process of bank operation is divided into the input stage of capital and manpower, the profit stage of capital operation, and operation stage, and a two-stage DEA network model is constructed. By measuring the overall operating efficiency of China's 15 banks from 2017 to 2022, the results show that the new dynamic network DEA model can better distinguish the efficiency of China's banks from the single-stage DEA model. In the new dynamic network model, the total factor productivity of most banks in China is reduced to varying degrees, which is greatly affected by pure technical efficiency.

The nature of rigidity and low energy density of polypyrrole (PPy)‐based electrodes limits their wide application in flexible energy storage devices. In this study, reduced graphene oxide (rGO) wrapped polypyrrole (PPy)/oxidized carbon cloth (OCC) (rGO@PPy/OCC) is prepared by the polymerization of pyrrole using MnO2 as the oxidant on the surface of OCC followed by the adsorption and reduction of graphene oxide (GO). The prepared rGO@PPy/OCC electrode exhibits a high gravimetric specific capacitance of 547 F g−1 at a current density of 0.5 A g−1 and a high area specific capacitance of 1641 mF cm−2 at a current density of 1.5 mA cm−2. It nearly maintains the initial capacitance after 8000 cycles at a high scan rate of 200 mV s−1 and at a large current density of 10 A g−1. Moreover, the flexible rGO@PPy/OCC electrodes are used to construct flexible solid‐state supercapacitors (FSSC). The FSSC based on rGO@PPy/OCC exhibits a high energy density (33.89 Wh kg−1 and 101.81 µWh cm−2) and a capacitance retention of 95.10% after 1000 bending cycles, demonstrating the excellent cycling stability and flexibility. Therefore, it is potential for rGO@PPy/OCC as a flexible electrode to fabricate high‐performance FSSC. [ABSTRACT FROM AUTHOR]

Guide star assisted wavefront shaping techniques have been exploited for focusing and imaging through turbid media by addressing a scatter inverse pattern. However, the turbid medium is required to be steady before finding the proper correction pattern, which limits applications in focusing and imaging through dynamic media, such as turbid water or blood. This study proposes a holography-based dual-polarization computational wavefront shaping method for imaging objects at variant depths behind dynamic turbid media. The orthogonal polarized output speckles of a point source (considered as a guide star) and an object are simultaneously recorded in holograms in separate regions of a single CCD camera. The holograms of the point source and object are subjected to the same distortion regardless of whether the media is static or dynamic. The hologram of the point source is used to determine the correction phase pattern for the distortion, while that of the object is used to record the complex scattered wavefront of the object. To reconstruct a clear object image, the wavefront of the scattered object is digitally corrected using the correction phase pattern and is then transferred to the image plane by calculating the transmission of the angular spectrum. Benefiting from the autofocusing feature of digital holography, objects at different depths can be recovered from a single shot hologram pair. The potential applications of the proposed method in diverse dynamic scattering media are demonstrated by imaging through a moving diffuser, turbid water, and pig blood with optical depth beyond 10. [ABSTRACT FROM AUTHOR]

Abstract Polpyrrole (PPy)/Ag nanocomposites were successfully synthesized at the interface of water and ionic liquid by one-step UV-induced polymerization. Highly dispersed PPy/Ag nanoparticles were obtained by controlling the experimental conditions. The results of Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy revealed that the UV-induced interface polymerization leaded to the formation of PPy incorporating silver nanoparticles. It was also found that the electrical conductivity of PPy/Ag nanocomposite was about 100 times higher than that of pure PPy.

Capacity drop (CD) at overloaded bottlenecks is a puzzling traffic flow phenomenon with some internal and complicated mechanisms at the microscopic level. Capacity drop is not only important for traffic flow theory and modelling, but also significant for traffic control. A traffic model evaluating traffic control measures needs to be able to reproduce capacity drop in order to deliver reliable evaluation results. This paper delivers a comprehensive overview on the subject from the behavioral mechanism perspective, as well as from microscopic and macroscopic simulation points of view. The paper also conducts comparable studies to replicate capacity drop at freeway ramp merges from both macroscopic and microscopic perspectives. Firstly, the subject is studied using the macroscopic traffic flow model METANET with respect to ramp merging scenarios with and without ramp metering. Secondly, one major weakness of commercial microscopic traffic simulation tools in creating capacity drop at ramp merges is identified and a forced lane changing model for ramp-merging vehicles is studied and incorporated into the commercial traffic simulation tool AIMSUN. The extended AIMSUN carefully calibrated against real data is then examined for its capability of reproducing capacity drop in a complicated traffic scenario with merging bottlenecks. The obtained results demonstrate that reproducible capacity drop can be delivered for the targeted bottlenecks using both macroscopic and microscopic simulation tools. [ABSTRACT FROM AUTHOR]

Constructing a multi-dimensional education and teaching quality evaluation system is the key content of China’s higher education reform. In order to establish a quality evaluation system suitable for the portfolio assessment, we take the construction of “new engineering” and the certification goal of engineering education as the guiding ideology, taking the VALUE rubrics as the reference system and taking the cell engineering course as the object. The course assessment and evaluation structure and course assessment standards are reconstructed and refined, and a complete cell engineering course quality evaluation system suitable for portfolio assessment was constructed. The establishment of this course quality evaluation system can provide reference for the construction of other professional course quality evaluation systems of the same nature in colleges and universities. [ABSTRACT FROM AUTHOR]

Tinnitus is an auditory phantom percept that affects the perception of sound in the patient’s ears, and the incidence of prolonged tinnitus is as high as ten to fifteen percent. Acupuncture is a unique treatment method in Chinese medicine, and it has great advantages in the treatment of tinnitus. However, tinnitus is a subjective symptom of patients, and there is currently no objective detection method to reflect the improvement effect of acupuncture on tinnitus. We used functional near-infrared spectroscopy (fNIRS) to explore the effect of acupuncture on the cerebral cortex of tinnitus patients. We collected the scores of the tinnitus disorder inventory (THI), tinnitus evaluation questionnaire (TEQ), hamilton anxiety scale (HAMA), and hamilton depression scale (HAMD) of eighteen subjects before and after acupuncture treatment, and the fNIRS signals of these subjects in sound-evoked activity before and after acupuncture treatment. According to the fNIRS detection results of tinnitus patients, acupuncture increased the concentration of oxygenated hemoglobin in the temporal lobe of tinnitus patients, and affected the activation of the auditory cortex. The study may reflect the neural mechanisms of acupuncture treatment for tinnitus and ultimately help to provide an objective evaluation method for the therapeutic effect of acupuncture treatment for tinnitus. [ABSTRACT FROM AUTHOR]

A new mixed-amido complex (Me2N)3Ta(C1)[N[(Si[Me.sub.3]).sub.2]] (1) was prepared from the reaction of [([Me.sub.2]N).sub.3]Ta[Cl.sub.2] with 1 equiv, of LiN[(Si[Me.sub.3]).sub.2]. The reactions of 1 with 1 equiv, of LiN[(Si[Me.sub.3]).sub.2] or [([Me.sub.2]N).sub.3]Ta [Cl.sub.2] with 2 equiv, of LiN[(Si[Me.sub.3]).sub.2] gave [([Me.sub.2]N).sub.3]TaN(Si[Me.sub.3])Si[Me.sub.2]C[H.sub.2] (2) with a four-membered metallaheterocyclic ring through [gamma]-hydrogen abstraction. In the solid state, 1 adopts a distorted trigonal bipyramidal geometry with the -N[(Si[Me.sub.3]).sub.2] and -C1 ligands in the equatorial and axial positions, respectively. The X-ray structure of 2 reveals that it is in a distorted trigonal bipyramidal geometry with a planar metallaheterocyclic ring. Key words: tantalum, [gamma]-hydrogen abstraction, C-H activation, amido complexes, metallacycle.

Functional hydrogels are promising in various fields such as sensors, portable devices and flexible electronics. However, it is still a challenge to prepare a multifunctional hydrogel with conductivity and magnetism, as well as a variety of excellent properties. In the work reported, MnFe2O4 nanoparticles were first loaded on polypyrrole (PPy) nanotubes using a chemical co‐precipitation method. By incorporating PPy/MnFe2O4 nanocomposites with poly(vinyl alcohol) (PVA), PVA‐PPy/MnFe2O4 (PPM) hydrogels were successfully prepared with the aid of borax. These hydrogels are not only ultra‐stretchable (over 1100%) and re‐moldable, but also conductive and magnetic. Moreover, the hydrogels can self‐heal within 15 s in air and 30 s in water, and adhere to various substrates repeatedly. A sensor based on the PPM hydrogel exhibits excellent performance in real‐time monitoring of magnetic field attraction and is reusable. The hydrogels can be further applied to touch‐screen pens. This work provides new opportunities for the rational design of other multifunctional hydrogels for potential applications in flexible sensors, wearable devices and health monitoring. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Capacity drop at congested freeway bottlenecks is well known with a lot of field observations. This paper studies coordinated ramp metering (RM) and mainstream traffic flow control (MTFC) as well as their integration (RM+MTFC) for freeway traffic, with particular attention to effects of capacity drop on the performance of traffic control measures. Via mathematical analysis and comprehensive simulation studies under an optimal control framework, the work has revealed a capacity-drop-related mechanism that MTFC and ramp metering are based on to take effects, and obtained a number of important conclusions: (1) applications of any control measure (RM, MTFC, or RM+MTFC) in freeways are justified by the existence of capacity drop in field; (2) an appropriate usage of the control measures can effectively prevent the activation of potential bottlenecks on freeways and hence avoid capacity drop; (3) any control measure is beneficial for a large majority of the driver population in a freeway network if it can manage to increase the accumulated total network exit flow; (4) it is a common misconception that ramp metering would simply transfer traffic loads from the freeway mainstream to on-ramps. The work has also highlighted the strengths, weaknesses, and applicability of ramp metering and MTFC. [ABSTRACT FROM AUTHOR]

Super-resolution structured illumination microscopy (SR-SIM) has attracted a great deal of attention in the past few decades. As a wide-field imaging technique, SR-SIM usually suffers from issues relating to out-of-focus background, particularly when imaging thick samples. In this study, we develop an integrated SIM with simultaneous SR and optical sectioning (OS) capabilities, facilitating SR imaging of stacked optical sections, with the out-of-focus background suppressed. The combination of the merits of SR and OS is realized by means of a new image reconstruction algorithm. We confirm the validity of the integrated SIM, both experimentally and in simulation. We anticipate that this integrated SIM will assist biologists in obtaining much clearer SR images in relation to thick specimens. [ABSTRACT FROM AUTHOR]