A CNN-Based Single-Stage Occlusion Real-Time Target Detection Method

Aiming at the problem of low accuracy of traditional target detection methods for target detection in endoscopes in substation environments, a CNN-based real-time detection method for masked targets is proposed. The method adopts the overall design of backbone network, detection network and algorithmic parameter optimisation method, completes the model training on the self-constructed occlusion target dataset, and adopts the multi-scale perception method for target detection. The HNM algorithm is used to screen positive and negative samples during the training process, and the NMS algorithm is used to post-process the prediction results during the detection process to improve the detection efficiency. After experimental validation, the obtained model has the multi-class average predicted value (mAP) of the dataset. It has general advantages over traditional target detection methods. The detection time of a single target on FDDB dataset is 39 ms, which can meet the need of real-time target detection. In addition, the project team has successfully deployed the method into substations and put it into use in many places in Beijing, which is important for achieving the anomaly of occlusion target detection.

Microstructure and Magnetic Properties of Anisotropic Nd-Fe-B Magnets Fabricated by Single-Stage Hot Deformation

Anisotropic Nd-Fe-B magnets were fabricated by the single stage hot deformation (SSHD) method. The magnetic properties of the anisotropic Nd-Fe-B magnets are as follows: the maximum energy product is 234.7 kJ·m-3, remanence 1.16 T and coercivity 684.3 kA·m-1. A study of the relationship between microstructure and magnetic properties for the anisotropic Nd-Fe-B magnets was carried out. The results show that the grains of Nd2Fe14B have grown up preferentially along the direction perpendicular to the pressing direction.

Fatigue Properties of RPC under Cyclic Loads of Single-stage and Multi-level Amplitude

Fatigue properties of Reactive Powder Concrete （RPC） under axial compression of single-stage and multi-level amplitude in cycles were studied. The tests reveal the fatigue life, the strain and residual life of the RPC samples. Through the analysis of the test results under cyclic loads of single amplitude, the S-N curve of RPC and the evolution rule of macro-damage of RPC were presented, which can be divided into latency stage, stable development stage and instability development stage according to the evolution pattern of the fatigue crack. Accordingly, the development of longitudinal deformation presents the similar three-stage-model, and the proportion of each stage is 15%, 75%, and 10%. According to test results, the fatigue strength reduction factor is 0.564. We brought forward an empirical formula to predict the life of RPC via total longitudinal strain and got the evolving rule for the residual strength of the RPC. The analysis of the test results under cyclic loads of multi-level amplitude shows that the strain under this loading pattern experiences three stages. The characteristic value for the residual strain was obtained. The irreversible damage and non-linear evolution of RPC was described by the development of the residual plastic strain.

A High-Efficiency Single-Stage Low-Power Photovoltaic Inverter System with Maximum Power Point Tracking Control

This paper proposes a single-stage inverter system with maximum power point tracking control (MPPT) applicable in low-power photovoltaic (PV) energy conversion systems. The proposed system is successfully implemented using a single digital signal processor (DSP) TMS320F2808. The proposed single-stage inverter system has the following features: 1) the ability to harvest the maximum PV power using two simple and effective current sampling methods;2) flexible topology based on the positioning of DC link capacitor on the outside of the inverter bridge circuits;3) reduced volume and higher efficiency than the conventional two-stage inverters, and 4) MPPT accuracy of 99.3% with overall efficiency of 90% under the full-load condition.

A Novel Single-Switch Single-Stage Electronic Ballast

A single-stage single-switch high- frequency electronic ballast topology is presented. The circuit topology is the integration of a buck power- factor-correction （PFC） converter and a class E resonant inverter with only one active power switch. The buck converter is operated in discontinuous conduction mode and at a fixed switching frequency, and constant duty cycle to achieve high power factor and it can be controlled easily. Detailed analysis of the operation and characteristics of the circuit is provided. Simulation results satisfy present standard requirements.

Feature-Grounded Single-Stage Text-to-Image Generation

Recently,Generative Adversarial Networks(GANs)have become the mainstream text-to-image(T2I)framework.However,a standard normal distribution noise of inputs cannot provide sufficient information to synthesize an image that approaches the ground-truth image distribution.Moreover,the multistage generation strategy results in complex T2I applications.Therefore,this study proposes a novel feature-grounded single-stage T2I model,which considers the“real”distribution learned from training images as one input and introduces a worst-case-optimized similarity measure into the loss function to enhance the model's generation capacity.Experimental results on two benchmark datasets demonstrate the competitive performance of the proposed model in terms of the Frechet inception distance and inception score compared to those of some classical and state-of-the-art models,showing the improved similarities among the generated image,text,and ground truth.

Kilowatt-level supercontinuum generation in a single-stage random fiber laser with a half-open cavity

The random distributed-feedback fiber laser(RFL) is a new approach to obtain a high-power stable supercontinuum(SC) source.To consider both structure simplification and high-power SC output,an innovative structure achieving a kilowatt-level SC output in a single-stage RFL with a half-open cavity is demonstrated in this paper.It consists of a fiber oscillator,a piece of long passive fiber and a broadband coupler,among which the broadband coupler acting as a feedback device is crucial in SC generation.When the system has no feedback,the backward output power is up to298 W under the pump power of 1185 W.When the feedback is introduced before the pump laser,the backward power loss can be reduced and the pump can be fully utilized,which could promote forward output power and conversion efficiency significantly.Under the maximum pump power of 1847 W,a 1300 W SC with spectrum ranging from 887 to1920 nm and SC conversion efficiency of 66% is obtained.To the best of our knowledge,it is the simplest structure used for high-power SC generation,and both the generated SC output power and the conversion efficiency are highest in the scheme of the half-opened RFL output SC.

Clinical Outcomes and Risks of Single-stage Bilateral Unicompartmental Knee Arthroplasty via Oxford Phase III

Background： Osteoarthritis often affects the joint bilaterally, and the single-stage （SS） unicompartmental knee arthroplasty （UKA） is advantageous in terms of a single anesthesia administration, a short hospital stay, lower medical costs, and enhanced patient convenience. However, the complication risk of SS UKA continues to be debated. The aim of this article was to evaluate the clinical effectiveness, complications, and functional recovery of SS and two-stage （TS） UKA. Methods： From January 2008 to December 2013, we compared a series of 36 SS UKA with 45 TS UKA for osteoarthritis. The mean age was 65.4 years （range： 55-75 years）. The mean body mass index was 25.2 kg/m^2 （range： 22-29 kg/m^2）. The preand post-operative Oxford Knee Scores （OKSs）, complications, operative times, tourniquet times, the amount of drainage, and hemoglobin （Hb） were evaluated. The Chi-square test, Fisher＇s exact test, and paired and grouped t-tests were used in this study. Results： The mean tbllow-up was 50 months. No complications of death, fat embolism, deep vein thrombosis, and prosthetic infection were reported. Patients who underwent SS U KA had a shorter cumulative anesthesia time （ 113.5 vs. 133.0 rain, P 〈 0.01 ）. There were no significant variations between the values of the mean tourniquet time, the amount of drainage, pre- and post-operative Hb in the different groups. No patient required a blood transfusion. No statistical differences were found in the complications between two groups （P 〉 0.05）. At the final follow-up, the mean OKS improved from 39.48 ±5.69 to 18.83 ± 3.82 （P 〈 0.01 ）, with no statistical differences between the two groups （P 〉 0.05）. Patients who underwent SS UKA had a faster recovery. Conclusions： The single-staged UKA offers the benefits of a single anesthesia administration, redticed total anesthetic time, decreased overall rehabilitation time, and absence of an increase in perioperative mortality or complications compared with the TS bilateral UKA.

Analytical analysis of single-stage pressure relief valves

The article presents an explicitly straightforward formulation of the stationary and dynamic behaviour of a pressure relief valve (PRV). This includes an analytical solution for the static p-Q-characteristic, the step and harmonic response and a stability criterion using elementary operations only. It also mathematically proves the intrinsic connection between the gradient of the static p-Q-characteristic and the stability. Thus, the new method offers four main advantages.

Effect and mechanism of carbon sources on phosphorus uptake by microorganisms in sequencing batch reactors with the single-stage oxic process

To investigate the chief reason for phosphorus uptake by microorganisms affected by substrates in sequencing batch reactors with the single-stage oxic process,two typical substrates,glucose (R1) and acetate (R2) were used as the sole carbon source,and the performances of phosphorus removal and the changes of intracellular storage were compared. The experimental results showed that the phenomenon of excess phosphorus uptake was observed in two reactors,but bacteria's capability to take in phosphorus and its intracellular storage were obviously different under the same operational condition. After steady-state operation,total phosphorus (TP) removed per MLVSS in R1 and R2 was 6.7―7.4 and 2.7―3.2 mg/g,respectively. The energy storage of poly-β-hydroxyalkanoates (PHA) was nearly constant in R1 during the whole period,and another aerobic storage of glycogen was accumulated (the max accumulation of glycogen was 3.21 mmol-C/g) when external substrate was consumed,and then was decreased to the initial level. However in R2,PHA and glycogen were both accumulated (2.1 and 0.55 mmol-C/g,respectively) when external substrate was consumed,but they showed different changes after the period of external consumption. Compared to rapid decrease of PHA to the initial level,glycogen continued accumulating to the peak (0.88 mmol-C/g) in 2 h of aeration before decreasing. During the aeration,the accumulations/transformations of internal carbon sources in R1 were higher than those in R2. In addition,obvious TP releases were both observed in R1 and R2 other than PHA and glycogen during the long-term idle period; moreover,the release content of phosphorus in R1 was also higher than that in R2. The researches indicated that different aerobic metabolism of substrate occurred in R1 and R2 due to the different carbon sources in influent,resulting in different types and contents of aerobic storage accumulated/translated in bacteria of R1 and R2. As a result,ATP content provided for phosphorus uptake was different in R1 and R2,and the capability to take up phosphorus was also different from each other.

A PSR single-stage flyback LED driver with simple line regulation and quasi-resonant operation

A single-stage flyback driving integrated circuit （IC） for light-emitting diodes （LEDs） is proposed. With an average primary-side current estimation and negative feedback networks, the driver operates in the boundary conduction mode （BCM）, while the output current can be derived and regulated precisely. By means of a simple external resistor divider, a compensation voltage is produced on the ISEN pin during the turn-on period of the primary MOSFET to improve the line regulation performance. On the other hand, since the delay time between the time that the secondary diode current reaches zero and the turn-on time of the MOSFET can be automatically adjusted, the MOSFET can always turn on at the valley voltage even if the inductance of the primary winding varies with the output power, resulting in quasi-resonant switching for different primary inductances. The driving IC is fabricated in a Dongbu HiTek＇s 0.35μm bipolar-CMOS-DMOS process. An 18 W LED driver is finally built and tested. Results show that the driver has an average efficiency larger than 86%, a power factor larger than 0.97, and works under the universal input voltage （85-265 V） with the LED current variation within ±0.5%.

梯度递减曝气实现一体化部分短程硝化、厌氧氨氧化耦合反硝化工艺(SPNAD)的稳定运行

为了解决一体化部分短程硝化、厌氧氨氧化耦合反硝化(single-stage partial nitritation,anammox and denitrification,SPNAD)系统中部分短程硝化由于过曝气难以稳定维持及短程硝化出水不稳定的问题,在以氨氮质量浓度为80 mg/L、化学需氧量(chemical oxygen demand,COD)质量浓度为150 mg/L的生活污水为进水的SPNAD系统中,通过曝气量控制进行了60 d的稳定进水负荷试验.在连续曝气控制0.3~0.5 mg/L的低溶解氧(dissolved oxygen,DO)过程中,会依次出现3次明显的DO跃变点Ta、Tb、Tc.结果表明:Tb可作为COD的降解完成指示点,Tc可作为部分短程硝化停曝气的指示点,Tc时刻NH4+-N、NO2--N平均质量浓度分别为20.11、22.83 mg/L,NO2--N和NH4+-N的质量浓度比值为0.93~1.37,适宜作为厌氧氨氧化进水;以DO变化率Δρ(DO)/Δt≥0.04 mg/(L·min)作为渐减曝气量和停止曝气量的设定值;将该梯度递减曝气控制策略应用于以实际生活污水(NH4+-N质量浓度为41.4~75.5 mg/L)为进水的SPNAD系统中,稳定实现了平均96.7%的总氮去除率(nitrogen removal ratio,NRR),平均出水总氮(total nitrogen,TN)质量浓度为2.11 mg/L.通过近150 d的试验为SPNAD系统的稳定短程硝化的稳定维持提出了一种梯度递减曝气控制策略,应用该控制策略可灵活调节本系统适应低氨氮、低ρ(COD)/ρ(TN)城市生活污水的水质变化且出水远优于国家一级A排放标准.

NEWTYPE SINGLE—STAGE DC／AC INVERTER

This paper presents two kind to pologies of newtype single-stage inverter with half-bridge and push-pull con-struction.The half-bridge single-stage DC/AC topo-logyis suited for high input voltage,and the push-pull single stage DC/AC topology is suited for low input voltage.The principles lf the two topologies are introduced.Ths-oretical and experimental results verify that they are suit-ed for small power DC/AC applications because of the ex-cellent performances such as simple construction,smallvolume,light weight and high reliability.

The Research of Three-phase Boost/Buck-boost DC-AC Inverter

This paper presents a new inverter based on three-phase Boost/Buck-boost single-stage inverter. The basic configuration of the new topology and their fundamental principle are firstly introduced, the method of design double-loop controller and sliding mode controller are clarified, analyzed and compared in the following. Finally the validity and feasibility of the new topology are tested by simulation. The results indicate that regulation of the voltage transfer ratio and output frequency can be realized optionally by the new converter, furthermore the harmonic distortion of waveform is low. So the inherent drawback of low voltage transfer ratio of traditional converter is effectively settled. This study may provide inspiration for further engineering application.

Laparoscopic Management of Undescended Testis: Results and Outcomes in a Pediatric Population

Aim: This study aimed to evaluate the results of the laparoscopic treatment of high and intra-abdominal undescended testes. Methods: A retrospective study was carried out from 2014 to 2021 at the Centre medico-chirugicale d’urologie in Douala. We consulted the clinical records of 27 patients aged 6 - 15 years who underwent laparoscopic orchiopexy at our hospital. We included patients with unilateral or bilateral undescended testes as detected by palpation and excluded patients with incomplete clinical records. The data collected were entered into Microsoft Excel 2016 and exported to Epi info 7 for analysis. Continuous variables were presented as mean values and standard deviations while categorical variables were presented as frequencies and percentages. The threshold for statistical significance was set at p Results: The ages of the 27 participants ranged from 6 years to 15 years, with a mean age of 10.22 ± 2.68 years. Hypospadias was an associated abnormality in 7.41% of participants. The mean duration of the surgical procedure was 80.56 ± 30.30 minutes. The overall success rate of the laparoscopic procedure was 95.83%. The mean duration of postoperative hospital stay was 26.67 ± 7.69 hours. The only postoperative complication we encountered was testicular atrophy, which occurred in 7.41% of participants. All our patients underwent single-stage laparoscopic procedures. Conclusion: Laparoscopy, which is the technique of choice for the diagnosis and management of undescended testis, is more rapid, more effective, and characterized by a shorter hospital stay and fewer postoperative complications compared to open surgery. Single-stage procedures are as effective and safe as two-stage procedures.

新凉水塔风机振动问题的治理

针对凉水塔风机振动较大，提出了从电机开始逐级单试，解决国产凉水塔风机振动的一种行之有效的方法。

Design of a 1.12Gb/s 11.3mW low-voltage differential signaling transmitter

This paper presents a 1.12 Gb/s 11.3 mW transmitter using 0.18μm mixed signal complementary metal- oxide semiconductor technology with a 1.8 V supply voltage. This transmitter implements a high-speed transmission with 1.2 V common-mode output voltage, adopting a low-voltage differential signaling （LVDS） technique. A multiplexer （MUX） and an LVDS driver are critical for a transmitter to complete a high-speed data transmission. This paper proposes a high power-efficiency single-stage 14 ： 1 MUX and an adjustable LVDS driver circuit, capable of driving different loads with a slight increase in power consumption. The prototype chip implements a transmitter with a core area of 970 × 560μm2, demonstrating low power consumption and adjustable driving capability.

A MARKOVIAN APPROACH TO DETERMINING PROCESS MEANS WITH DUAL QUALITY CHARACTERISTICS

This paper studies a production system where products are produced continuously and whose specification limits are specified for screening inspection. In this paper, we consider dual quality characteristics and different costs associated with each quality characteristic that falls below a lower specification limit or above an upper specification limit. Due to these different costs, the expected total profit will greatly depend on the process parameters, especially a process mean. This paper develops a Markovian-based model for determining the optimum process means with the consideration of dual quality characteristics in a single-stage system. The proposed model is then illustrated through a numerical example and sensitivity analysis is performed to validate the model. The results showed that the optimum process mean for both quality characteristics have a significant effect on the performance of the system. Since the literature survey shows that dealing with multi-quality characteristics is extremely limited, the proposed model, coupled with the Markovian approach, provides a unique contribution to this field.