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Second-order photonic topological insulators (SPTIs) featured with topological edge and corner states provide an intriguing way for steering light in integrated optics. However, existing SPTIs have narrow bulk gaps for tightly confining topological edge and corner states. In this paper, we propose a bi-directional evolutionary structural optimization (BESO) method to inversely engineer SPTIs in C3-symmetric lattices. At first, we maximize the first band gap of a photonic crystal (PC) enforced with C3 symmetry. Then, the topological phase transition is achieved by inverting the optimized PC. Highly localized topological edge and corner states are formed at the boundary and corner between the optimized PC and its inversion-symmetry partner. The bandwidth of the topological edge state for TE modes achieves 44.9%, exceeding two times of the current record. The robust of the topological corner states is further demonstrated. Our work provides a new route for designing SPTIs, paving the way towards their practical application.

Background:At present, the mechanism of reciprocal ST-segment depression(RSTD) is still not clear. Purpose : We proposed the mechanism of RSTD: the action potential of negative electrode of the lead was weakened or disappeared, and the AP of positive electrode could not be completely offset. The electrocardiograms of patients with acute STEMI were analyzed to explore the mechanism of RSTD. Methods: The electrocardiogram and angiography of 85 STEMI patients were retrospectively analyzed to summarize the characteristics of ST segment changes. Results: A total of 85 patients were included, of which 75 were patients with RSTD (10 patients with anterior myocardial infarction had no RSTD), all 45 patients with inferior myocardial infarction had limb leads RSTD, and 37 of them had anterior lead ST segment depression.Thirty patients with anterior myocardial infarction were accompanied by mild ST segment changes in the limb leads. According to the characteristics of RSTD, it is speculated that the mechanism of RSTD is that the action potential of infarct area decreased , which could not offset the action potential in non-infarct area. By using this mechanism, all ST segment changes in STEMI can be explained by the proposed mechanism, and the value of the ST segment changes can be calculated in limb leads. Conclusion: the mechanism of RSTD in acute myocardial infarction is that the negative electrode action potential of the lead was weakened or disappeared, and the positive electrode action potential could not be completely offset, resulting in ST segment depression.

With the rapid development of magnetic field sensors, non‐contact monitoring by magnetic field measurement can provide an advanced sensing technology for the smart transmission and distribution network. Magnetic fields can store energy and act as the media for transferring energy. Magnetic field based energy storage/conversion may become one of the solutions for energy generation in smart grids. Magnetoresistance (MR) sensors have been applied to magnetic field measurement. Compared with Hall effect sensor, an MR sensor has higher sensitivity. Therefore, MR sensors can response to the speed change of the synchronous machine accurately and quickly. The operation status of the synchronous machine can be monitored by measuring the magnetic field of the synchronous machine. Magnetic field based measurement can directly detect the non‐symmetry of the structure, together with its non‐invasive character, hence will find more applications in future.

Topology-driven nonlinear light-matter effects open up new paradigms for both topological photonics and nonlinear optics. Here, we propose to achieve high-efficiency second-harmonic generation in a second-order photonic topological insulator. Such system hosts highly localized topological corner states with large quality factors for both fundamental and second harmonic waves, which could be matched perfectly in frequency by simply tuning the structural parameters. Through the nonlinear interaction of the doubly resonant topological corner states, unprecedented frequency conversion efficiency is predicted. In addition, the robustness of the nonlinear process against defects is also demonstrated. Our work opens up new avenues toward topologically protected nonlinear frequency conversion using high-order photonic topological modes., Comment: 7 pages, 8 figures

The Dirac-like cones underlie many unique properties of photonic crystals (PhCs). This paper aims to design fabrication-friendly PhCs with Dirac-like cones for transverse magnetic (TM) modes and transverse electric (TE) modes at different specific frequencies. By maximizing the minimum of a collection of the local density of states corresponding to different judiciously selected sources, this paper demonstrates that Dirac-like cones formed by the degeneracy of a doubly degenerate mode and a single mode at different desired frequencies are successfully obtained. The exotic wave manipulation properties associated with Dirac-like cones, such as cloaking, wavefront shaping and tunneling through bent channels, are exhibited based on the optimized structures. This paper also demonstrates that the proposed method could be used for the design of PhCs with one Dirac-like cone at ω , and one monopolar band at 2 ω at the Γ point, and PhCs with third order Dirac-like cones, which have potential applications in nonlinear optics. All topological patterns of the optimized PhCs are reported and have regular and smooth features, meaning they can be readily fabricated.

The recently proposed Radon single pixel imaging (RSPI) is based on Radon transform and considered to be a prospective technique in many fields, such as computed tomography, feature detection, classification and so on. And because of the fact that the exact implementation of inverse discrete Radon transformation does not exist, an approximate algorithm, filtered back projection, is employed to reconstruct the result images in RSPI. However, the presence of disturbing streak artifacts emerging from high-contrast structures hinders the high-quality reconstructions, especially at low sampling rates. In order to get rid of this dilemma, a novel single pixel imaging technique, which employs a few projection angle patterns to achieve sparse projection angle sampling and utilizes compressive sensing to reconstruct the result images, is proposed. Simulation and experimental results demonstrate that the image quality reconstructed by the proposed technique is much higher than that of RSPI at low sampling rates. Additionally, the proposed technique also has advantages in a lot of fields such as tomographic reconstruction at low radiation.

Real-time tracking of fast-moving object have many important applications in various fields. However, it is a great challenge to track of fast-moving object with high frame rate in real-time by employing single-pixel imaging technique. In this paper, we present the first single-pixel imaging technique that measures zero-order and first-order geometric moments, which are leveraged to reconstruct and track the centroid of a fast-moving object in real time. This method requires only 3 geometric moment patterns to illuminate a moving object in one frame. And the corresponding intensities collected by a single-pixel detector are equivalent to the values of the zero-order and first-order geometric moments. We apply this new approach of measuring geometric moments to object tracking by detecting the centroid of the object in two experiments. The root mean squared errors in the transverse and axial directions are 5.46 pixels and 5.53 pixels respectively, according to the comparison of data captured by a camera system. In the second experiment, we successfully track a moving magnet with a frame rate up to 7400 Hz. The proposed scheme provides a new method for ultrafast target tracking applications.

The realization of unidirectional acoustic transmission (UAT) has recently aroused great attention owing to the versatile possibility in acoustics-based applications. This paper extends the bi-directional evolutionary structural optimization (BESO) method to the design of phononic crystal (PC) for achieving UAT. The optimization objective is to enlarge the minimum imaginary part of wave vectors along Γ-X while keep that along Γ-M less than the constraint value. We systematically studied the design of symmetric and asymmetric PCs at various frequencies. Numerical examples demonstrate that the proposed optimization algorithm is effective for creating the partial band gap at the specified frequency. The UAT with high rectifying efficiency is then successfully realized by placing the optimized PC in a bend wave guide. The results also show that the asymmetric PCs are more favorable for the design of broadband UAT devices compared with symmetric ones.

We have demonstrated the fabrication of homogeneously distributed In0.3Ga0.7N/GaN quantum nanodisks (QNDs) with a high density and average diameter of 10 nm or less in 30-nm-high nanopillars. The scalable top-down nanofabrication process used biotemplates that were spin-coated on an In0.3Ga0.7N/GaN single quantum well (SQW) followed by low-damage dry etching on ferritins with 7 nm diameter iron cores. The photoluminescence measurements at 70 K showed a blue shift of quantum energy of 420 meV from the In0.3Ga0.7N/GaN SQW to the QND. The internal quantum efficiency of the In0.3Ga0.7N/GaN QND was 100 times that of the SQW. A significant reduction in the quantum-confined Stark effect in the QND structure was observed, which concurred with the numerical simulation using a 3D Schrodinger equation. These results pave the way for the fabrication of large-scale III–N quantum devices using nanoprocessing, which is vital for optoelectronic communication devices.

The propagation of evanescent waves inside phononic band gaps is important for the design of phononic crystals with desirable functionalities. This paper extends the bi-directional evolutionary structure optimization (BESO) method to the design of phononic crystals for maximizing spatial decay of evanescent waves. The optimization objective is to enlarge the minimum imaginary part of wave vectors at a specified frequency. The study is systematically conducted for both out-of-plane and in-plane waves at various frequencies. Numerical examples demonstrate that the proposed optimization algorithm is effective for designing phononic crystals with maximum spatial decay of evanescent waves. Various topological patterns of optimized phononic crystals are given. The results also show that the proposed optimization algorithm can successfully overcome difficulties in opening band gap at desirable frequencies, especially for the complete band gap and multiple band gaps.

Topological photonics revolutionizes some of the traditional approaches to light propagation and manipulation, and it provides unprecedented means for developing novel photonic devices. Recently discovered higher-order topological phases go beyond the conventional bulk-edge correspondence for photonic crystals and introduce novel opportunities for topological protection. Here, we introduce an intelligent numerical approach for inverse design of higher-order photonic topological insulators with great flexibility for controlling both topological edge and topological corner states. In particular, we consider the second-order photonic topological insulator and design several structures supporting both edge and corner states at different frequencies. By carefully programming these structures, we suggest a novel approach for topological routing of the edge and corner states by changing the operational frequency. Our finding paves the way to integrated topological photonic devices with novel functionalities., 12 pages, 5 figures

This paper provides a study on a novel octagonal multi-cell tube with functionally graded thickness (FGT) under multiple loading angles. First, comparative analysis on the FGT tube and the counterpart tube with uniform thickness(UT) under multiple loading angles reveal that the energy absorption is more superior for the FGT tube when the loading angle exceeds the lower bound of the transition range of the UT tube. Second, parametric study on the FGT tube indicates that thickness gradient exponent and thickness range have significant effect on its crashworthiness. Third, multiobjective optimizations of the FGT tube are conducted, aiming to maximize specific energy absorption(SEA) and minimize initial force(IPF) under multiple loading angles, based upon the Non-dominated sorting genetic algorithm(NAGA-Ⅱ) and RBF technique. The optimized FGT tube demonstrates better crashworthiness than the UT tube in all design cases. These findings can provide valuable guidelines for the design of multi-cell tube with functionally graded thickness under multiple loading angles.

Vibrations propagating underground may have harmful effects on adjacent buildings and human health. Recently, the notion of phononic crystals has been introduced and applied to isolate vibrations below the ground. In this paper, considering the viscoelastic material model, the complex band diagrams are suggested to analyse the transportation of vibrations in the composite foundation consist of soil and different underground structures. In the complex band diagram, the minimum imaginary part of the wave vectors is taken as the index to measure the ability of the pile group to weaken vibrations. Several types of underground barriers, including circular piles, continuous walls, and multi-layer piles, are analysed. The result shows that multi-layer piles can induce local resonance and achieve an attenuation zone at the low-frequency level. The attenuation effect of periodic barriers is then verified by transmission models. The results show that the complex band diagrams can quantitatively evaluate the isolation effect of periodic barriers, which is beyond the capability of classic band diagrams.

Using SolidWorks software, the finite element modal analysis of a vehicle-borne pollution monitoring lidar cabin is carried out. The lidar cabin for the integrated lidar can ensure that the lidar system has good maneuverability and can effectively monitor the emission of air pollution. Since lidar is an integrated system of optics, mechanism, electricity and calculation, the performance of the cabin is directly related to the safety of the equipment and the lidar to work properly. Firstly, the cubic structure is modeled to simulate the cubic structure. Then, the model of the cabin model is analyzed by using the simulation plug-in, and the first 10 modes and natural frequencies are analyzed and recorded. The calculation results show that the cabin is dominated by bending vibration, and the amplitude area is concentrated in the opening of some windows and doors on each board. Therefore, we should increase the number of reinforcement bars or the strength of the skeleton in the vicinity of the door and window. At the same time, to avoid the resonance and ensure the precision of the optical elements and the electrical components and avoid structural damage of the cabin, the incentive frequency should be keep away from the natural frequency of the cabin. The vehicle-borne lidar system has been put into operation, and the analysis results have direct meaning to the transport of the cabin and the normal work.

Lidar instruments are efficient detectors of air pollutants such as nitrogen dioxide (NO2). However, the measurement errors are not negligible due to the influence of the aerosol in the atmosphere. We present a novel lidar for measuring tropospheric NO2 vertical profiles. For improving the received powers, the emitter unit consists of two pulsed pump laser – dye laser combination, and use three wavelengths of 448.10nm, 447.20nm and 446.60 nm corresponding to the strong, medium and weak absorption of NO2 respectively. The effects of aerosol on tropospheric NO2 measurements by three - wavelength (448.10 -447.20 -446.60 nm) dual differential absorption lidar (dual-DIAL) and conventional two - wave length (448.10- 446.60nm) differential absorption lidar (DIAL) are theoretical analyzed, and their system err are computer simulated. Experimental results show that the three - wavelength dual - DIAL method is more effective to reduce the effects of aerosol than the two - wavelength DIAL method, and its system error is no more than 4% without correcting the aerosol effect.

The differential absorption lidar (DIAL) is a powerful and convenient tool for detecting the atmospheric trace gases. Based on dual wavelength differential absorption principle, we develop a set of lidar for measuring the concentration and distribution of the atmospheric SO2. This paper introduces the software, hardware and specific parameters of each subsystem in detail, then horizontal and vertical azimuth detection results are given. This lidar system adopts two tunable narrow linewidth dye lasers which pumped by Nd:YAG lasers, and produces l 600.10nm laser and 603.00nm lasers alternately. The lasers are frequency doubled by two second-harmonic crystals respectively and marked as λon=300.05nm and λoff=301.50nm which corresponds the strong absorption wavelength and the weak absorption wavelength of SO2 absorption spectrum. They are merged into one beam, and then expanded twelve times, and transmitted into the atmosphere coaxially with telescope finally. The back scattering signals are received by telescope system and converted into electrical signals by photomultiplier tube (PMT) after being collimated and filtered. These electrical signals are obtained by A/D acquisition card and stored in the computer for retrieving the concentration and distribution of the atmospheric SO2. Some field experiments are conducted in Huainan Atmospheric Science Research Institute, and we get some satisfactory results. On June 28th, 2016, the mean concentration of atmospheric SO2 is about 3.7 ppb in the range from 0.8km to 3.0km in horizontal azimuth. It conforms with the result of ground instrument from meteorological department. The vertical orientation detection is also performed at night of June 28th, 2016, and the atmospheric SO2 fluctuates in 0-5ppb which mainly exists below 1.5km.

Background: Explore the impact of second-generation bisphosphonate drugs pamidronate on proliferation and apoptosis of human multiple myeloma cell line in vitro. Verify the synergistic effect of combination of pamidronate and melphalan on apoptosis of myeloma cells and demonstrate that lactadherin is the most effective probe for apoptosis detection. Method: (1) Myeloma cells were treated with pamidronate or combination of melphalan and pamidronate at different concentrations. The cells were divided into 12 groups and treated with the drugs at intervals of 24 hours for 48 hours. After 48 hours treatment, inhibition rate of cell growth in different group were measured by MTT. (2) Two groups were treated with PBS buffer. PS exposure of the cells treated with drugs was detected using FITC-Annexin-V and FITC-lactadherin by flow cytometry. Result: The increase of the proliferation and effect of apoptosis by pamidronate on multiple myeloma cells was parallel as the increase of pamidronate dose. In combination with melphalan, the effect of apoptosis induction was stronger than single drug group. PS exposure detected by lactadherin was significantly increased as the increase of amidronate concentration. PS exposure in treated group is more than that of control group. Conclusion: Pamidronate exerts effects of growth inhibition and apoptosis induction on multiple myeloma cell in a dose-dependent way; Combination therapy increases apoptosis and exerts a synergistic effect; Lactadherin is the most effective probe in detecting myeloma cell apoptosis.

This study sought to assess the spatial relationship of repetitive rotational (RotA) or continuous activities (CA) to atrial delayed enhancement (DE-MRI, acquired at high resolution (1.5x1.5x1.25mm)) and low voltage areas

Anatomical liver resection is currently the preferred treatment for liver cancer. With the recent introduc- tion of medical microwave coagulation for liver metastases, anatomical hepatectomy may be performed more efficiently. The present study retrospectively reviewed the results of microwave tissue coagulation performed during anatomical liver resection for patients with liver disease at the TangDu Hospital (Xi'an, China) between January, 2009 and June, 2012. A total of 128 patients met the inclusion criteria and were divided into two groups for comparison; those treated with the microwave coagulation technique (n=66) and the conventional group (n=62), who were treated with standard partial hepa- tectomy. There was no reported perioperative mortality. The univariate analysis revealed that the duration of liver dissec- tion, intraoperative blood loss, intraoperative erythrocyte transfusion volume and alanine aminotransferase levels on the 5th postoperative day were significant ly different between the microwave and conventional groups (P