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Nonlinear dynamics of mutually injected twin-microring semiconductor lasers are studied numerically and experimentally. For the twin-microring laser, a bridge waveguide directly connecting two identical microrings is utilized to realize mutual optical injection or mode coupling. The coupling coefficient is related to the waveguide parameter and influences the mutual injection process dramatically. By adjusting the frequency offset between two microrings, four-wave mixing, injection locking, periodic, and multi-period oscillation states are observed from the experimental lasing spectra. The plentiful nonlinear dynamical states are induced by the mode interaction between the two microrings and can be well explained by the rate equations with mutual optical injection.

All-optical switching and multiple logic gates are experimentally demonstrated using AlGaInAs/InP hybrid square-rectangular lasers. Controllable bistability induced by saturable absorption in the square microcavity is achieved around the threshold with the square cavity in an open circuit state. Based on the bistability, all-optical switching operation is realized by injecting set/reset optical signals with the wavelengths around the lasing mode of 1529.9 nm and another high-Q mode at 1560 nm. Furthermore, mode competitions between three resonant modes around 1541 nm with an interval of 1.2 nm are used to realize all-optical multiple logic gates of NOT, NOR, and NAND functions under low-power optical pulses, with injecting currents to the square and rectangular sections. The static extinction ratio of 34, 40 and 24 dB are obtained for NOT, NOR, and NAND gates, respectively, and the dynamic extinction ratio over 10 dB of NOT function at 15 Gb/s, NOR and NAND functions at 2 Gb/s are demonstrated. With the merits of multifunctional operations, large optical injection wavelength tolerant ranges, low power consumption, small footprint and suitability for on-chip integration, the device offers a potential solution for all-optical signal processing in photonic integration circuits.

Dual-mode microcavity semiconductor lasers are investigated for potential applications in photonic microwave and optical frequency comb (OFC) generation. By regulating whispering-gallery modes (WGMs) in square microcavities, dual-mode lasing is achieved with frequency intervals ranging from tens to hundreds of gigahertz. In the square microcavities, the fundamental and first-order transverse WGMs have spatially separated field distributions, which allow stable dual-transverse-mode lasing with mode intervals inversely proportional to the cavity areas. Dual-transverse-mode square microcavity lasers are experimentally demonstrated with frequency intervals ranging from ∼35 to ∼150 GHz. Photonic microwaves and OFCs are successfully generated based on the dual-mode square microcavity lasers. To enhance the transverse-mode intervals, circular-side square microcavity lasers with a square hole in the center are proposed and demonstrated, and dual-transverse-mode lasing with a frequency interval up to ∼0.56 THz is obtained. Furthermore, a square-Fabry–Perot coupled-cavity microlaser is demonstrated to increase the output power and introduce an additional degree for manipulating the lasing modes. Dual-mode lasing is realized with a frequency interval of ∼0.5 THz, a single mode optical fiber coupled power of ∼3 mW, and a wavelength tuning range of ∼10 nm.

Whispering-gallery mode (WGM) microlasers are potential light sources for photonic integrated circuits and optical information processing. In this paper, an integrated twin circular-side octagon microlaser (TCOM) composed of two identical circular-side octagon microcavities (COMs) is proposed and demonstrated for realizing lasing mode control. In a TCOM, we found a global mode with the mode field of an “8” pattern (labeled “8” mode) in addition to weak coupling modes of traditional four-bounce modes. The “8” mode belongs to the whole coupled cavity and is insensitive to the refractive index offset of coupled COMs, but the weak coupling modes are strongly sensitive to the refractive index offset. Lasing mode transformation from multiple coupled modes to a single “8” mode is demonstrated by adjusting the refractive index offset through injection currents. Weak coupling modes for directly connected TCOMs and lasing mode control make the COM a potential unit for large-scale photonic integration and optical information processing.

We report nonlinear dynamics in directly connected twin circular-sided square microcavity semiconductor lasers with mutual optical injection. Rich nonlinear dynamics including injection locking, four-wave fixing, and multi-period oscillation states are observed experimentally by adjusting the mode frequency offset between two circular-side square microcavities. Internal optical injection or mode coupling can be realized directly in the connected twin circular-sided square microcavity lasers, which effectively relaxes device processing techniques of the integrated microcavities for photonic integration.

All-optical switch and multiple logic gates have been demonstrated using a hybrid-cavity semiconductor laser composed of a square microcavity and a Fabry–Perot cavity experimentally. In this paper, two-section tri-mode rate equations with optical injection terms are proposed and applied to study all-optical logic gates of NOT, NOR, and NAND operations utilizing the hybrid-cavity laser. Steady-state and dynamical characteristics of all-optical multiple logic gates are simulated, taking into account the influence of mode frequency detuning, gain suppression coefficients, mode Q factor, injection energy, and biasing current. All-optical logic NOT, NOR, and NAND gates up to 20, 15, and 20 Gbit/s are obtained numerically with dynamic extinction ratios of over 20, 20, and 10 dB, respectively, which are potential response speeds of the all-optical logic gates based on the hybrid-cavity semiconductor lasers.

Extremely noisy low light enhancement suffers from high-level noise, loss of texture detail, and color degradation. When recovering color or illumination for images taken in a dark environment, the challenge for networks is how to balance the enhancement for noise and texture details for a good visual effect. A single network is not suitable for solving the ill-posed problem of mapping the input image's noise to the clear target in the ground truth. To solve the problems, we pro-pose perceptual-details GAN (PD-GAN) utilizing Zero-DCE to initially recover illumination and combine residual dense-block Encoder-Decoder structure to suppress noise while finely adjusting the illumination. Besides, fractional differential gradient masks are integrated into the discriminator to enhance details. Experiment results demonstrate that PD-GAN outperforms other methods on the extremely low-light image dataset.

Long-term tracking algorithms need to track targets stably in long videos. Compared with short-term tracking, long-term tracking faces more complex challenges. Such as the background brightness distributed in the entire gray level, wide range of target scale changes, more frequent motion blur and occlusion and other challenges. Existing long-term tracking algorithms cannot solve these challenges well, and easily cause tracking box drift, which significantly decrease the accuracy and robustness of the algorithms. In this paper, we design a detection and tracking combined network that can implement a global instance search for the tracked target. We integrate deformable convolution into the siamese network to solve the target deformation problem during long-term tracking. Besides, guided anchor is adopted in RPN to generate more sparse and accurate proposals, which can decrease the interference of the background. We design the cascaded RCNN with template information to filter out proposals and refine coordinates. And finally, select the highest confidence proposal as the final tracking box. Experiments show that our method has a stronger discriminative ability and can get more accurate tracking boxes compared with other advanced trackers. On several long-term tracking benchmarks, our method has achieved excellent performance.

We theoretically and numerically study optical modes in regular-polygonal microcavities with non-uniform gain and loss, where high quality (Q) whispering-gallery-like modes typically appear as superscar states. High Q superscar modes can be described by the propagating plane waves in an effective rectangle formed by unfolding the periodic orbits and exhibit regular and predictable spatial field distributions and transverse-mode spectra. With non-uniform gain and loss, anti-Hermitian coupling between the transverse modes with close frequencies occurs according to the mode coupling theory, which results in novel mode properties such as modified mode spectra and field patterns, and the appearance of exceptional points. Numerical simulation results are in good agreement with the theoretical analyses, and such analyses are also suitable for other kinds of high Q microcavities with non-uniform gain and loss. These results will be highly useful for studying non-Hermitian physics in optical microcavities and advancing the practical applications of microcavity devices.

The in-phase/quadrature (I/Q) imbalance encountered in the zero-IF receiver leads to incomplete image frequency suppression, which severely deteriorates image rejection ratio (IRR) of the receiver system and must be improved using additional analog or digital signal processing. The I/Q linear phase imbalance (LPI) is the key of the I/Q imbalance, which consists of the time delay deviation (TDD) and the local oscillator (LO) phase offset. TDD is negligible in most literature, but it degrades system performance largely for wideband communication systems. This paper proposes a method based on the cross-power spectrum between the I/Q signal to address the estimation problem of LPI. Compared with other conventional methods, the proposed approach calculates LPI parameters simultaneously without any additional hardware. The MATLAB simulation is utilized to evaluate the effectiveness of the presented method. Moreover, the experimental platform of detailed design demonstrates the feasibility of the proposed estimation method, and IRR of the system before and after compensation shows that LPI has been accurately estimated and eliminated with the help of an appropriate compensation structure. Both reveal that the proposed method offers an effective solution to the LPI problem.

Beside pigment absorption and reflection by periodic photonic structures, natural species often use light scattering to achieve whiteness. Synthetic hydrogels offer opportunities in stimuli‐responsive materials and devices; however, they are not conventionally considered as ideal materials to achieve high whiteness by scattering due to the ill‐defined porosities and the low refractive index contrast between the polymer and water. Herein, a poly(N‐isopropylacrylamide) hydrogel network with percolated empty channels (ch‐PNIPAm) is demonstrated to possess switchable bright whiteness upon temperature changes, obtained by removing the physical agarose gel in a semi‐interpenetrating network of agarose and PNIPAm. The hydrogel is highly transparent at room temperature and becomes brightly white above 35 °C. Compared to conventional PNIPAm, the ch‐PNIPAm hydrogel exhibits 80% higher reflectance at 800 nm and 18 times faster phase transition kinetics. The nanoscopic channels in the ch‐PNIPAm facilitate water diffusion upon phase transition, thus enabling the formation of smaller pores and enhanced whiteness in the gel. Furthermore, fast photothermally triggered response down to tens of milliseconds can be achieved. This unique property of the ch‐PNIPAm hydrogel to efficiently scatter visible light can be potentially used for, e.g., smart windows, optical switches, and, as demonstrated in this report, thermoresponsive color displays., A channeled poly(N‐isopropylacrylamide) hydrogel is prepared using agarose as the removable template. The hydrogel shows bright whiteness and 18 times faster kinetics of transparency change compared to standard poly(N‐isopropylacrylamide) hydrogels. The highly efficient scattering of visible light can be utilized for applications such as smart windows and switchable passive displays.

To improve the anti-interference performance of a lightning current acquisition device, a redundant signal conditioning channel is adopted, i.e., an additional signal acquisition channel is provided to acquire the lightning current signal, and a dual-channel ADC is applied to acquire the two lightning current signals induced by the same conductor simultaneously. Then, the acquired data are sent to a DSP for similarity matching. If the similarity reaches the set value, the two lightning current data are considered to be matched and the lightning current data are determined to be valid and then stored, otherwise discarded, waiting for the arrival of next data. In this way, the interference signals are eliminated with true lightning current signals being retained only while the lightning current characteristic parameters are acquired and the lightning current signal waveform is reproduced, thereby improving the accuracy of lightning current monitoring. Also, this saves valuable storage resources, improves the processing efficiency and ensures real-time monitoring.

We propose and demonstrate a circular-side octagonal microcavity (COM) semiconductor laser with a spatially distributed current injection for manipulating the lasing modes. There are two types of high-quality-factor whispering-gallery (WG) modes with distinct field patterns in a COM: the four-bounced quadrilateral modes and the eight-bounced octagonal modes. By designing two separated p-electrodes, the COM laser is divided into two regions that are pumped independently to select specific modes for lasing. The two types of WG modes lase simultaneously when the two regions are injected with equivalent currents. Degeneracy removal of the quadrilateral modes is observed in both simulation and experiment when the two regions are injected with inequivalent currents. The quadrilateral modes are suppressed when one of the two regions is un-injected or biased with a negative current, and single-octagonal-mode lasing is realized. The results show that the lasing modes can be efficiently manipulated with the spatially distributed current injection considering the distinct field patterns of different WG modes in the microcavities, which can promote the practical application of the microcavity lasers.

The high coupling coefficient of wireless charging coupler can improve the transmission efficiency. To obtain higher coupling coefficient and lighter weight for double D (DD) coupler, the equivalent magnetic circuit and the expression of coupling coefficient are derived, which give some guidence for magnetic core optimization. Then different core structures are designed and compared by 3D Maxwell finite-element analysis. An optimized core structure is given and the experimental results show the validity. Then the theory method to evaluate charging zone is proposed, which gives a clear concept to confirm maximum vertical and horizontal offset.

Aim Symptomatic tracheobronchomalacia can be fatal. Successful treatment includes aortopexy. We report outcomes of the thoracoscopic approach in a single centre. Methods All patients undergoing thoracoscopic aortopexies from 2009 to 2018 were retrospectively reviewed. Data was reported as median (interquartile range). Risk factors for subsequent tracheostomy were analyzed with logistics regression model, p Results Twenty-one patients with mid to distal tracheomalacia (n = 17) and bronchial involvement (n = 4) were determined on bronchoscopy, tracheobronchogram, or CT thorax. Preoperative patient demographics and comorbidities, e.g., gastro-oesophageal reflux disease, prematurity, and cardiac anomalies were recorded. Indications for thoracoscopic aortopexy were apparent life-threatening event(s) (n = 14), recurrent chest infections (n = 5), and failure to wean invasive ventilation (n = 2). Thoracoscopic aortopexies (n = 20) with conversion to open (n = 1) were performed. Intraoperative bleeding (n = 2) occurred, and chest tube (n = 1) was inserted for monitoring. Intraoperative bronchoscopy (n = 17) confirmed improvement of tracheomalacia. Anesthetic time was 140 (90–160) minutes. Postoperatively, 2 patients had dehiscence of the aorta from the sternum. They underwent redo open aortopexy with posterior tracheopexy, and 1 required subsequent tracheostomy. Another 2 patients required tracheostomies. Potential risk factors for subsequent tracheostomy were investigated, and only the association of tracheobronchomalacia was close to significance (OR 16 (95% CI 0.95–267.03), p = 0.05). Follow up duration was 365 (72–854) days. Symptoms resolution occurred in n = 17 (81%) of patients. Conclusion Different modalities were used to delineate the site of tracheobronchomalacia and its etiology. Tracheomalacia with bronchial involvement may be a risk factor for subsequent tracheostomy. Level of Evidence Level 3 (Case Series).

Bag of words was first used in the field of text categorization. In recent years, with the development of image processing technology, Bag of words has also been widely used in image classification and image retrieval. The use of Bag of words has simple and effective features, but in the image. There are still many defects in the classification. After researching and analyzing the SVM image classification model based on traditional Bag of words, it is found that there are two shortcomings in the traditional Bag of words in image classification: (1) the accuracy of visual word representation is not high; (2) the flexibility is poor. According to these two defects, combined with the contrast words and Hamming embedding technology, the traditional word bag model is improved, and a high discriminative force of Bag of words is applied and combined into the SVM image classification model. A SVM image classification model based on high discriminative Bag of words is presented. The experimental results show that the accuracy and applicability of the classification are improved.

Hybrid-cavity of a Fabry-Perot (FP) cavity and a microcavity with the microcavity as a wavelength selective reflector are reported for realizing single mode semiconductor lasers. Mode coupling between a microcavity mode and a FP mode results in mode Q factor enhancement and stable single mode operation. Furthermore, optical bistability are realized in the hybrid lasers as the unbiased microcavity working as a saturable absorption. Two bistability regions are realized for the hybrid lasers around threshold current and above threshold with mode competition, and all-optical flip-flop is demonstrated.

Naoxintong capsule (NXT), a Chinese medicine, has performed excellent effects on the prevention and treatment against cardiovascular diseases. NXT is a fine powder mixture without any herb extraction, and there must be lots of ingredients hard to be absorbed. However, little is known about the correlation between the NXT's cardioprotective effects and gut microbiota. Herein, we report the effect of NXT on the development of cardiovascular diseases and clarify the correlation between NXT's cardioprotective effects and gut microbiota. In the current study, minipigs were selected and fed with high-fat diet and NXT daily for successive 8 months. During the process, up to 18 biomedical parameters were monthly determined to observe the dynamic changes after NXT treatment. At the end of experimental process, pathological examinations of heart, coronary artery, carotid artery, thoracic aorta, and abdominal aorta were conducted by HE staining and 16SrDNA sequencing, and analyzing of gut microbiota were conducted. Our results showed that NXT's effects against cardiovascular diseases were through regulating blood lipid profiles, inhibiting vascular inflammation, enhancing antioxidant capacity, and alleviating myocardial injury, without damages on liver and kidney particularly. Concurrently, we also found that long-term administration of NXT increased the diversity of gut microbiota, influenced the microbiome structure and composition stably, and revered the increase of the ratio of the Firmicutes to Bacteroidetes (F/B ratio) in relative abundance. Specifically, our results revealed some key bacterium of Caproiciproducens (enhanced), Sutterella (enhanced), Erysipelotrichaceae (enhanced), and Romboutsia (decreased) that were closely involved in NXT's effects. Taken together, our study demonstrates that NXT can inhibit the development of cardiovascular diseases by ameliorating high-fat diet-induced metabolic disorders and partly through improving gut microbiota.

In this Letter, we design and realize a hybrid-cavity laser with single- or dual-mode lasing states and study the nonlinear states of the laser under external optical feedback (EOF). The laser at a dual-mode state easily and directly enters the chaotic state without periodic oscillation states and display chaos for a much wider range of the EOF magnitude than the laser at a single-mode state. A flat chaotic signal is obtained for the laser at a dual-mode lasing state under a weak EOF benefitting from the low-frequency energy enhancement caused by mode competition between the dual modes.

In recent years, granular temporary plugging agents (TPA) have been widely studied, especially in repeated fracturing operations, to stimulate oil and gas production in unconventional petroleum reservoirs. They can divert the hydraulic fracturing energy to form more complex fractures that make oil and gas more easily flow into production well. Pre-formed particle gels (PPGs), as deformable particles, are often used in petroleum reservoir water management operations because of their high strength, simple fabrication process, and environmental friendliness. However, their application as TPA is rarely reported. In this paper, degradable PPGs (DPPGs) were employed, and their temporary plugging performance was studied in the laboratory. Bottle tests were first conducted to investigate the swelling and degradation performance. Results show that DPPGs exhibit good swelling ability in an extended range of brine salinity (20000 to 400000 ppm), and DPPGs can be fully degraded, and the degradation time increase with temperature. According to the temporary plugging performance by core flooding experiments, the plugging strength increased with the injection pressure, dry particle size, and swelling ratio (less than 20 times). However, the addition of smaller size particles will prevent large particles from forming deformable blockage on the matrix end surface, and subsequent water flow channels will be easily created, so the plugging performance of the DPPGs will decrease. The above experimental results can provide an experimental and theoretical basis for the application of DPPGs in repeated fracturing operations in unconventional reservoirs.

We have studied the optical modes in Fabry–Perot (FP) cavities with spatially distributed gain and loss. Exceptional points (EPs) are observed not only in the parity-time (PT) symmetric FP cavity but also in these cavities with specially designed gain-loss distributions. Such phenomena result from the interference between the reflected and transmitted waves at the interface of the gain-loss regions, which cannot be explained by the dual-mode coupling theory that is widely used in the description of PT-symmetric coupled-cavity systems. The optical waves in the FP cavity traveling in the forward and backward directions have extremely different intensities at the gain-loss interface, and hence the interference will greatly affect the transmission of the weaker one and lead to unique mode properties such as EPs in the FP cavity. The mode properties are sensitive to the gain-loss distribution, but the split of modal loss is a universal phenomenon and can be used for lasing mode control.

We propose gapless-coupled twin circular-side square microcavities (TCSMs), and experimentally demonstrate the TCSM semiconductor lasers with weak mode coupling. The introduction of circular sides modifies the field distributions of the whispering-gallery modes and enables gapless coupling for the TCSMs without degrading the mode quality factors. Numerical simulation results show crossing and avoided crossing of the modes in the TCSMs with the variation of the wavelength difference and gain-loss contrast between the two cavities. By tuning the injection currents of the laser cavities, mode crossing is observed from the experimental lasing spectra of a TCSM laser. The realization of weak mode coupling in TCSM lasers indicates that the gapless-coupled deformed square microcavities provide a feasible robust coupling scheme for photonic integration.

Whispering-gallery mode (WGM) microcavities with the merits of small mode volumes and high quality (Q) factors have attracted great research interests as potential low-power-consumption light sources for photonic integration. We propose and demonstrate deformed square microcavity lasers with the flat sidewalls replaced by circular arcs as converge mirrors to control the WGMs inside the laser cavity. The ray dynamic analysis results indicate that the circular-sides can confine the light rays with stable islands, although full chaotic dynamics are observed under certain deformation. With the numerical simulation of the circular-side square microcavities, ultrahigh-Q modes are obtained owing to the elimination of the scattering losses from the vertices, and a reduction of mode Q factors due to the chaotic ray dynamics is also observed. Different transverse modes have distinct light trajectories, which results in a difference of the effective roundtrip length and a controllable transverse mode interval. Low threshold lasing is achieved experimentally due to the high Q factors of the WGMs. The lasing spectra can be engineered by designing the cavity geometry for the waveguidecoupled circular-side square microcavity lasers. The robust structure and ultrahigh-Q of the waveguide-coupled microlasers provide a potential solution for the compact light sources in photonic integrated circuits.

Hybrid square/rhombus-rectangular lasers are proposed and demonstrated. Single mode operation with a continuous wavelength tunable range of 25nm is realized with side mode suppression ratio (SMSR) > 30dB and the highest SMSR of 44dB.

Mode competition bistability is reported for a square-rectangular coupled cavity semiconductor laser. Single mode operations with a tuning range larger than 30 nm are realized for a coupled-cavity semiconductor laser with a deformed square microcavity.

All optical inverter is realized based on a hybrid square-rectangular laser. Dynamic performance up to 5 Gb/s is reached with extinction ratio of 10 dB.

We have demonstrated circular-side square microcavity lasers with a center hole to control the lasing modes. Dual-transverse-mode lasing with wavelength intervals ranging from 1 to 4.4 nm is realized experimentally for the 16μm-side-length square microlasers.

As DC transmission has been used widely, HVDC and EHVDC Flexible cables are the development direction of power grid in the future. The biggest existing problem of HVDC cable is accumulation of space charges in XLPE insulation and researchers tried to suppress space charges by improving shielding layers which are directly contact with XLPE. Four kinds of HVDC and HVAC cable shielding materials from different manufacturers were selected in this paper. Transmission electron microscope (TEM), thermogravimetric analysis (TGA), volume resistivity and mechanical properties of shielding materials were measured and analyzed. Commercially available insulation material of HVDC cable was selected to prepare samples for space charge tests and the pressure wave propagation (PWP) method was adopted to study space charge injecting effects of shielding materials on XLPE insulation. The results showed that addition of conductive carbon black in HVDC cable shielding materials were lower than that in HVAC cable shielding materials, although volume resistivity of these shielding materials were almost same. Tensile strength and hot set properties of these shielding materials were almost same, but elongation at break of HVDC cable shielding materials were better. HVDC cable shielding materials had a more positive effect on suppressing space charges in XLPE insulation on the basis of lower field enhancement factor (FEF) caused by space charges.

An effective method for millimeter-wave (mmW) carrier generation from a dual-transverse-mode microsquare laser is experimentally demonstrated. By directly modulating the dual-mode microsquare laser at 6.7 GHz, multiple sidebands are generated due to enhanced modulation nonlinearity, and the lasing modes with an interval of 40 GHz are phase-locked. MmW carriers up to 47 GHz, corresponding to seven times that of the modulation frequency, are achieved with a linewidth below 10 Hz. The single-sideband phase noises of the signals keep the same level after transmission over 2.5 km of optical fiber.

Aim Biliary atresia (BA) remains a rare disease in Europe with an estimated incidence of 1 in 15–20,000 livebirths. While the Kasai portoenterostomy (KPE) is regarded as the standard operation for BA, there is no consensus on optimum adjuvant therapy. We sought to determine the variation in therapy and opinion in centers known to have an interest in pediatric hepatobiliary surgery across Europe. Methods A survey of current pre- and postoperative practice was circulated to surgeons and centers known to have an interest in BA. Data are quoted as median (range). Results There were 19 completed center forms from 12 different countries. Annual (new) caseload varied with 10 centers reported seeing ≤5 patients/year and 4 centers >15 patients/year. The distribution of BA variants was isolated BA (80 [60–100]%), syndromic BA (10 [3–35]%), cystic BA (5 [1–15]%), and cytomegalovirus (CMV) immunoglobulin M (IgM)-positive BA (5 [0–15]% (CMV serology only formally tested in 16 centers). The commonest age group at KPE was 51 to 60 days (n = 8). All centers performed an exclusively open KPE, although one used laparoscopy for diagnosis. A steroid-based postoperative regimen was used in 11/19 (58%) centers, but with marked variation in dose and duration. Commonest perioperative antibiotics were a combination of piperacillin-tazocin (n = 7) and gentamicin (n = 8). Oral prophylactic antibiotics, with varying duration (4–52 weeks) were used in 13/19 (68%) centers. If CMV serology was positive, seven centers would treat with specific antiviral therapy. Other postoperative medication included ursodeoxycholic acid (UDCA) (n = 19), phenobarbitone (n = 4), and cholestyramine (n = 2). Self-declared clearance of jaundice in centers varied from 30 to 40% (n = 3) to > 60% (n = 5). Conclusion All surveyed European centers continue to perform an exclusively open KPE, but there is no consensus on a standard adjuvant drug regimen. Self-declared outcome post-KPE also appears to be variable though the reasons are obscure.

In the real face detection, AdaBoost based algorithm usually has a higher false positive rate and loss rate. But it faces with the problem of long training time, susceptible to face deflection, obstruction and other factors. In view of the above problems, an improved face detection algorithm is proposed, which can reduce the training time and improve the training speed by using the feature processing, and the detection rate is improved by introducing the skin color detection based on YCgCr color space. Through experimental testing, the proposed algorithm can solve the occlusion, angle, light and other problems to a certain extent.

Spectral engineering has been demonstrated for the circular-side square microlasers with an output waveguide butt-coupled to one vertex. By carefully optimizing deformation parameter and waveguide connection angle, undesired high-order transverse modes are suppressed while the mode Q factors and the transverse-mode intervals are enhanced simultaneously for the low-order transverse modes. Dual-mode lasing with pure lasing spectra is realized experimentally for the circular-side square microlasers with side lengths of 16 μm, and the transverse mode intervals can be adjusted from 0.54 to 5.4 nm by changing the deformation parameter. Due to the enhanced mode confinement, single-mode lasing with a side-mode suppression-ratio of 36 dB is achieved for a 10μm-side-length circular-side square microlaser with a 1.5μm-wide waveguide.

A new architecture of null steering antenna based upon the technology of space-time adaptive processing (STAP) with optimized parameters is proposed. The new STAP antenna is comprised of multiple channels and each channel is a transversal filter. So separate sensor element for the reference signal is not required because the antenna gets the reference signal from the first sensor of the auxiliary array. Furthermore, the least mean square (LMS) algorithm is employed to calculate the weight vector. Detailed analysis about the relationship between noise power and output error is investigated. Compared with the traditional null steering antenna in space or space-time domain, the new approach obtains more freedom degrees and can suppress both the wideband and narrowband interferences more efficiently with deeper nulls. Simulation results shows that the proposed architecture outperforms the conventional STAP techniques for interference suppression.

Waveform character Searching is one of the important means for a digital oscilloscope to capture and analyze signals of interest, and also marks the waveform analysis capability of the digital oscilloscope. Its performance determines the design level of the oscilloscope directly. At present, domestic digital oscilloscopes generally show low efficiency in waveform character Searching. For this reason, a research on the FPGA+DSP-based waveform character Searching hardware co-processing technology was conducted. Details on the operating principle and design method were given, and comparative analyses were performed on software and hardware-based Searching efficiency. The results of simulation and testing indicate that this method can effectively improve the real-time processing capability of an oscilloscope.

In order to improve the utilization of system resources and enhance the network throughput, this paper focuses on the cooperative network coding which combines the advantages of both network coding and cooperative diversity. Both theory and simulation proves that it can provide better performance in BER and NC gain.

The MIMO technology, namely through many antenna clear signal transmission and the receive, in does not increase the extra band width under the premise, enhanced the channel capacity greatly. Understood the MIMO channel the characteristic, studies the channel modelling method, unified the FPGA parallel characteristic, the design has manufactured one kind based on XILINX FPGA the platform MIMO channel analog meter, through the massive test confirmation, and did with the theoretically simulation performance compares, has confirmed the accuracy.

Hybrid square/rhombus-rectangular lasers (HSRRLs) consisting of a Fabry–Perot (FP) cavity and a square/rhombus microcavity (SRM) are proposed and demonstrated for realizing single-mode lasing with a wide wavelength tuning range. The SRM is a deformed square microcavity with a vertex extended to the FP cavity to control the coupled mode field pattern in the FP cavity. Single-mode operation with a side-mode suppression ratio (SMSR) over 45.3 dB is realized, and a wide wavelength tuning range of 21 nm with SMSR >35 dB is further demonstrated by adjusting the injection currents of the SRM and the FP cavity simultaneously. Furthermore, a 3-dB modulation bandwidth of 14.1 GHz and an open-eye diagram at 35 Gb/s are demonstrated for the HSRRL.

All-optical flip-flop has been demonstrated experimentally based on our optical bistable hybrid square-rectangular lasers. In this paper, dual-mode rate equations are utilized for studying the optical bistability in the two-section hybrid-coupled semiconductor laser. A phenomenological gain spectrum model is constructed for considering the mode competition in gain section and saturable absorption effect in the absorptive section in a wide wavelength range. The mechanisms of the optical bistability are verified in the aspect of the distribution of carriers and photons in the two-section hybrid-coupled cavity. In addition, we find that with the adjustment of the device parameters, both of the width and biasing current for achieving the bistability can be tuned for a wide range. Furthermore, a dynamic response of all-optical flip-flop is simulated, using a pair of set/reset optical triggering pulses, in order to figure out the laws for faster transition time with lower power consumption.

We propose and demonstrate an optoelectronic oscillator with a directly modulated AlGaInAs/InP integrated twin-square microlaser for generating wideband frequency-tunable microwave signals with low phase noise. Apart from the relaxation oscillation peak, the modulation response of the twin-square microlaser working at the mutual optical injection state exhibits a significant enhancement around the beating frequency of the lasing modes in the two square cavities owing to the photon-photon resonance. A self-sustaining oscillation can be generated around the modulation response peak with the lowest loop loss occurring at the relaxation oscillation frequency or the beating frequency, depending on the practical state of the twin-square microlaser. High-quality tunable microwave signals ranging from 2.22 to 19.52 GHz are generated with single sideband phase noises below -110 dBc/Hz at the 10 kHz offset frequency and side-mode suppression ratios of approximately 40 dB by tuning the injection currents of the twin-square microlaser.

This systematic review was performed to assess the necessity and complications of stenting before extracorporeal shock wave lithotripsy in the management of upper urinary stones.A systematic research of PubMed®, EMBASE® and the Cochrane Library was performed to identify all randomized controlled trials. The comparisons were about the outcomes and complications of extracorporeal shock wave lithotripsy in the management of upper urinary stones with or without Double-J stenting before extracorporeal shock wave lithotripsy, including stone-free rate, Steinstrasse, lower urinary tract symptoms, hematuria, fever, urinary tract infection, pain and analgesia, auxiliary treatment, and nausea and vomiting. We used the Cochrane Collaboration's Review Manager (RevMan) 5.0.2 software for statistical analysis.Eight randomized controlled trials were included in analysis that reported 876 patients in total, divided into the stented group of 453 and the stentless group of 423. All studies recorded the stone-free rate and the results of the meta-analysis showed no difference between the groups (RR 0.97, 95% CI 0.91-1.03, p = 0.27). The total incidence of Steinstrasse in the stented group was similar to that of the stentless group with the exception of 1 study. However, the incidence of lower urinary tract symptoms was significantly higher in the stented group than in the stentless group (RR 4.10, 95% CI 2.21-7.61, p0.00001). Significant differences could not be found in hematuria, fever, urinary tract infection, pain and analgesia, auxiliary treatment, or nausea and vomiting between the groups.The systematic review suggested significant advantages of stenting before extracorporeal shock wave lithotripsy compared to in situ extracorporeal shock wave lithotripsy in terms of Steinstrasse. However, stenting did not benefit stone-free rate and auxiliary treatment after extracorporeal shock wave lithotripsy, and it induced more lower urinary tract symptoms. More high quality, randomized controlled trials are needed to address this issue.

This paper analyses the relationship between the output power, the transmission efficiency and the frequency, load and coupling coefficient of the four kinds of magnetic coupled resonant wireless charging system topologies. Based on mutual inductance principle, four kinds of circuit models are established, and the expressions of output power and transmission efficiency of different structures are calculated. The difference between the two power characteristics and efficiency characteristics is compared by simulating the SS (series-series) and SP (series-parallel) type wireless charging systems. With the same parameters of circuit components, the SS structure is usually suitable for small load resistance. The SP structure can be applied to large load resistors, when the transmission efficiency of the system is required to keep high. If the operating frequency deviates from the system resonance frequency, the SS type system has higher transmission efficiency than the SP type system.

In order to study the frequency characteristics of the wireless energy transmission system based on the magnetic coupling resonance, a circuit model based on the magnetic coupling resonant wireless energy transmission system is established. The influence of the load on the frequency characteristics of the wireless power transmission system is analysed. The circuit coupling theory is used to derive the minimum load required to suppress frequency splitting. Simulation and experimental results verify that when the load size is lower than a certain value, the system will appear frequency splitting, increasing the load size can effectively suppress the frequency splitting phenomenon. The power regulation scheme of the wireless charging system based on magnetic coupling resonance is given. This study provides a theoretical basis for load selection and power regulation of wireless power transmission systems.

Composite electromagnetic scattering from a two-dimensional (2D) ship-like target on a one-dimensional sea surface is investigated by using the flnite-difierence time-domain (FDTD) method. A uniaxial perfectly matched layer is adopted for truncation of FDTD lattices. The FDTD updated equations can be used for the total computation domain by choosing the uniaxial parameters properly. To validate the proposed numerical technique, a 2D inflnitely long cylinder over the sea surface is taken into account flrst. The variation of angular distribution of the scattering changing with incident angle is calculated. The results show good agreement with the conventional moment method. Finally, the in∞uence of the incident angle, the polarization, and the size of the ship-like target on the composite scattering coe‐cient is discussed in detail.

The method of auto set makes it more convenient for users to capture and observe the unknown signal. It focuses on some related key technologies which are discussed in detail in the paper, such as initialize, judge whether all input channels are signaled or not, search vertical sensitivity by binary search method only if the channel has signal, set up the vertical sensitivity when multipath signals need to separate by the related software method, display the bias voltage, setup gear of time base according to the base-time system. And the experimental results are presented; the efficiency of complete design scheme is much higher than before.

The frequency response mismatch among time-interleaved analog-to-digital converters (TIADC) system's different channels will degrade sampling accuracy. We propose a frequency mismatch algorithm, where compensation filter is designed basing on adaptive strategy. Adopted with this digital post-processing technique, the filter calibrates frequency-related mismatches effectively. Experimental results verify its effectiveness.