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A solid-state transformer (SST) offers direct medium voltage to low voltage conversion, resulting in higher system efficiency and a smaller footprint compared to traditional transformers. Among the popular SST architectures, a two-stage system comprising a cascade H-bridge (CHB) as the first stage and a resonant converter as the second stage has gained prominence. However, the CHB circuit introduces power ripple at twice the line frequency, leading to poor power density due to the necessity of large bus capacitors for power regulation. To address this issue, a partial fluctuation power control method is proposed that allows a portion of the power ripple to flow through the resonant converter, thus reducing the size of the bus capacitors. Additionally, a loss evaluation is presented to calculate the losses related to fluctuation power, and a magnetic component optimization methodology is conducted to achieve an optimal tradeoff between loss and size for the resonant converter. The effectiveness of the proposed control method is demonstrated through a 15 kW 180 kHz CLLC converter module, achieving a peak efficiency of 98.8% and a power density of 3.1 kW/L. Furthermore, the bus capacitor size is reduced to 60% without compromising overall losses when compared to conventional regulated resonant converters.

An enclosed microgroove is a vital surface microstructure that is difficult to prepare on the surfaces of difficult-to-machine electrically conductive materials using conventional methods. Electrical discharge machining (EDM) is suitable for this task. It is obtained primarily through layer-by-layer scanning EDM with micro-column electrodes or reciprocating EDM with foil electrodes. However, owing to the small cross-sectional size of the electrodes, a stable machining process is challenging to achieve, which seriously reduces the machining efficiency. To solve these problems, this study proposed ultrasonic vibration-assisted EDM using a laminated electrode possessed strong anti-interference properties for enclosed microgrooves. The effects of ultrasonic vibration on the EDM of microgrooves with single foil and laminated electrodes were investigated. The results show that ultrasonic vibration could improve the machining efficiency of the two types of electrodes and significantly improve the profile quality of the microgrooves prepared using laminated electrodes. When the amplitude was 3 μm and the frequency was 30 kHz, the bottom sidewall corner radius of microgrooves machined by brass foils in laminated electrodes was 28 μm, the width, depth, and roughness of microgrooves machined by copper foils in laminated electrodes were approximately 78 μm, 229 μm and 0.7 μm, the material removal rate was 0.0072 mm3/min. Based on the optimized parameters, inverted “convex” microgrooves with fine consistency were successfully prepared using laminated electrodes on Ti–6Al–4V alloy surfaces. The machining time was reduced by 40% for each microgroove compared with using the single foil electrode. This study provides a new method for preparing complex microgrooves.

This study evaluated the bioequivalence of omalizumab, a humanized monoclonal antibody against immunoglobulin‐E (IgE), with one of its biosimilar candidates. The study was designed as a randomized, double‐blind, parallel‐controlled trial. A total of subjects who met the inclusion criteria and did not meet the exclusion criteria were dynamically randomly assigned to receive the test drug or the reference drug with a single subcutaneous injection of 150 mg by the minimization method. The test group and the reference group had similar demographic characteristics and baseline characteristics of total IgE. The 90% confidence interval of the geometric average ratio of the area under the serum concentration–time curve from the time 0 to the time of last quantifiable concentration, the area under the serum concentration curve from time 0 to infinity, and the maximum observed serum concentration between the 2 groups were within 80%‐125%, showing bioequivalence. The changing trend of total and free IgE in the 2 groups was similar after administration, proving the pharmacodynamic similarity. The 2 groups had no significant difference in the positive rate of antidrug antibodies, and the total positive rate of neutralizing antibodies was 0. The incidence of treatment‐emergent adverse events and treatment‐related adverse events were similar between the 2 groups, with no serious adverse events. This study shows that the test drug had similar pharmacokinetics, immunogenicity, and safety to the reference omalizumab in healthy male subjects.

Underwater localization is necessary for autonomous operation of underwater robots. Limited field of view for onboard vision systems can result in poor reliability of visual localization for underwater robots during autonomous docking. This article proposes a dual-type marker fusion-based visual localization method for underwater autonomous docking. First, a visual localization scheme integrating light sources and ArUco markers is designed according to positioning requirements based on varying fields of view for onboard vision in autonomous docking operations. The arrangements of the light sources and ArUco markers are both analyzed and optimized to ensure the reliability and efficiency of visual localization. Then, an underwater visual localization algorithm with dual marker fusion is proposed for high-accuracy localization with a restricted field of view. Extended underwater experiments are conducted to verify the feasibility and stability of the proposed method across various distances. The obtained results provide valuable references for the design and optimization of visual navigation systems for underwater robots.

Transformer design is critical to high-power high-frequency dc/dc resonant converters. For the design of a high-current transformer with parallel windings, current sharing, resonant inductance integration, as well as performance optimization are still quite challenging. Therefore, a comprehensive analytical model of the current distribution between the parallel litz wire windings is developed in this article. Based on this model, a novel winding structure is proposed to eliminate the current discrepancy. Furthermore, the performances of two typical resonant inductance integration methods are compared when applied to parallel windings. With the selected transformer structure, loss and volume optimization is also conducted. It is worth mentioning that the proposed transformer structure and design principles have good scalability and can be extended to higher power ratings easily. Finally, the analysis and design are verified in two 100-kHz transformers for a 30-kW LLC resonant converter. The current difference between parallel windings does not exceed 3.6%. The efficiency and power density of the transformer at 30 kW is up to 99.6% and 22.4 kW/L, respectively.

This paper investigates the cruise control problem of unmanned ground vehicle (UGV) platoons from the implementation perspective. Unlike most existing works related to platoon cruise control which rely on positioning infrastructures such as lane markings, roadside units, and global navigation satellite systems (GNSS), this paper explores a new problem: platoon cruise control in environments without positioning infrastructures. The introduction of this constraint disables most existing cruise control approaches. To address this problem, an integrated localization and planning framework is proposed, which is composed of three modular algorithms. Firstly, to localize multiple vehicles in a common coordinate system, a collaborative localization algorithm is developed through matching local perceptions of different vehicles. Secondly, to maintain the desired platoon configuration, the historical trajectory of the preceding vehicle is reconstructed, based on which the target state is planned for the following vehicle. Finally, a virtual controller based algorithm is designed to generate feasible trajectories for the following vehicle in real time. The proposed framework has two salient features. Firstly, it does not depend on positioning infrastructures and does not introduce additional positioning sensors, such as GNSS/INS modules, ultra-wideband (UWB) devices, magnetic meters and so on, as long as each vehicle is equipped with a perception sensor (Lidar, radar or camera), which however is essential equipment for nowaday autonomous systems. Secondly, the proposed framework does not depend on direct observations between vehicles to achieve relative localization, making it applicable in non-line-of-sight (non-LOS) situations. Real-world experiments have been conducted to validate the effectiveness, robustness and practicality of the proposed framework.

The test drug, a recombinant humanized monoclonal antibody, is a biosimilar candidate for the reference drug. The purpose of this study was to evaluate the bioequivalence of these two drugs. The study was divided into two parts, a pre‐study and a formal trial. The pre‐study included two subjects who were each given a single intravenous infusion of 6 mg/kg test drug. The formal trial was designed to be a randomized, double‐blind, parallel controlled trial in which 70 subjects were randomly assigned 1:1 to receive either test or reference drug as a single 6 mg/kg intravenous infusion. In the pre‐study, the immunogenicity was negative in both subjects and the safety of the test drug was considered to be good. The two groups in the formal trial had similar demographic characteristics. The 90% confidence interval of geometric mean ratios of area under the serum concentration‐time curve from the time 0 to the time of last quantifiable concentration, area under the serum concentration‐curve from time 0 to infinity, and maximum observed serum concentration between the test group and the reference group fell between 80% and 125% and the bioequivalence was recognized. There was no significant difference in the positive rate of antidrug antibodies. The treatment‐emergent adverse events in the test group were similar to those in the reference group. This study showed that the test drug has similar pharmacokinetics, immunogenicity, and safety to the reference drug in healthy male subjects.

Resistance spot welding (RSW) is widely used in manufacturing processes of automobiles, aircraft, high-speed trains and other equipment, its appearance quality not only affects the product appearance, but also reflects the internal defects of welding spots and the health statuses of welding equipment to a great extent. Nowadays, a few researchers have tried to use deep learning algorithms to detect the appearance qualities of welding spots, however, the relationships between defect types and welding spot positions are ignored and the subtle visual differences among different welding spots are not fully utilized. To this end, a fine-grained flexible graph convolution network (FFGCN) is proposed for vision inspection of resistance spot welds in this paper, which combines natural language processing with computer vision. Specifically, the prior knowledge of relationships between weld appearance qualities and their positions is mapped to point-wise space by knowledge graph, so the features in point-wise space can be mined by a flexible graph convolution network (FGCN). In the FGCN, multi-head attention mechanism is adopted to adaptively update the probabilistic matrix to generate multiple subgraphs, expand the spatial dimensions and increase feature information. Meanwhile, the optical features of weld images are excavated by a fine-grained network, in which the receptive field of model is enlarged and the number of pixels is ensured by dense atrous convolution. Besides, subtle visual differences between welding spots are captured by the bilinear attention convolution. Finally, the features in point-wise space and the visual features are combined by dot product to classify the appearances of welds. A six classification experiment for the vision inspection of resistance spot welds from engineering practice is implemented, results show that the proposed FFGCN has outstanding effect on the inspection of weld appearance qualities, it possesses faster convergence, more robustness, and its accuracy reaches 97.5%, which is higher than the commonly used visual classification algorithms.

Due to break space and time limits, an entirely new online curriculum of orthodontic education with online evaluation system has been structured and developed in the dental school, based on virtual reality simulation. At Nanjing Medical University, a new online orthodontic curriculum with programmatic assessment process was constructed and implemented based on competency‐based education (CBE). It was consisted of the online orthodontic theoretical lectures based on the National Open Online Course “Orthodontics,” the online journal club via the online “flipped classroom,” and the online orthodontic pre‐clinical training via the virtual learning network platform. In order to evaluate this curriculum, 94 Year 4 dental students took part to complete the online orthodontic curriculum. The mean total score of all the students was 91.99, and the element scores of the online theoretical lectures, journal club, virtual pre‐clinical training, and online final examination were respectively 96.83, 79.49, 96.00, and 87.02, which showed a good performance. According to the student feedback toward this curriculum via the online questionnaire, nearly 98% of the students showed agreement or strong agreement that the online orthodontic curriculum has enhanced their orthodontic theoretical understanding and orthodontic practical ability. As a student‐centered CBE, this online orthodontic curriculum with online evaluation system could provide both orthodontic theory and practice teaching for all the dental students at all times and places based on the online virtual mode, which enriched learners’ critical thinking, problem solving, and assessment skills.

A new type of coupling between unactivated olefins and nonstabilized alkyl radicals was achieved, which enabled the first intermolecular Heck-type reaction of cycloketone oxime esters and unactivated alkenes. This directing-group-based strategy was compatible with various unactivated alkenes and cyclobutanone-, cyclopentanone-, and cyclohexanone-derived oxime esters. Density functional theory calculations showed that both excellent regioselectivities and good diastereoselectivities could be ascribed to the 2-butanol-assisted concerted H–OBz elimination of the conformationally strained metallacyclic transition state.

A diverse collection of copper-catalyzed intermolecular aminative difunctionalizations of unactivated alkenes with N-halodialkylamines as the terminal dialkylamino source is reported. A bidentate auxiliary tethered on the alkene substrates is crucial, which can promote the migratory insertion of nonactivated alkenes into the aminyl radical–metal complex and stabilize the resultant high-valent copper intermediate to allow for further transformations. By employing this strategy, the intermolecular aminohalogenation reactions and a three-component aminoazidation reaction of unactivated alkenes with dialkylamino source were successively achieved in a remarkable regio- and stereoselective manner. These reactions were performed under neutral conditions and maintained excellent functional group tolerance toward a wide range of N-halodialkylamines and unactivated alkenes. Further mechanistic studies and DFT calculations supported a concerted migratory insertion of the C–C double bond into the aminyl radical–metal complex to form a Cu(III) intermediate.

The unpredictability of battery degradation behavior is a challenging issue impeding the development of battery applications, due to the complexity of the degradation and the limitation of state measurement methods. Nowadays, with accessible battery aging datasets and machine learning algorithms, there are opportunities for data-driven battery health prognosis. However, most of the previous work is restricted in the scope of full-discharge capacity records extrapolation, which has insufficient prospects in real-life applications. In this work, we propose using partial discharge information for degradation estimation and prediction. Our Gaussian process regression model achieves good performance by limited partial discharge information without requirements of feature selection. The accurate battery health prognosis in 300 cycles can be carried out by one partial-discharge cycle at any degradation stage. The capacity estimation gives around 1 % root mean square error (RMSE) when using 30 % information on the discharge process. As full-cycle discharge is not required, the proposed model can diagnose the battery state of health (SOH) with a limited portion of battery operation information extracted during the discharge process and reduce the effort of capacity tests. Further development of this method brings opportunities for battery state evaluation and prediction in real applications with better applicability and accuracy.

Background Probiotics are commonly used for the prevention of antibiotic-associated diarrhea (AAD). However, the optimum regimen remains controversial.Objective The objective of this article is to compare and rank the relative efficacy and tolerability among all available probiotic agents for AAD through a network meta-analysis.Methods Eligible studies were identified by searching PubMed, Embase, Medline, Cochrane library and Web of Science for randomized controlled trials (RCTs) that examined the efficacy of probiotic therapy for AAD. A random-effects model was applied within a frequentist framework. Quality of evidence was performed by the GRADE approach. The project was prospectively registered with PROSPERO (CRD 42016050776).Results Fifty-one articles (60 comparisons, 9569 participants), including 10 probiotic interventions, were identified. Lactobacillus rhamnosusGG (LGG) had the highest probability of being ranked best both in effectiveness (odds ratio (OR), 95% confidence interval (CI) = 0.28 (0.17, 0.47)) and tolerance (0.44 (0.23, 0.84)) on prevention of AAD. With regard to reducing Clostridium difficileinfection rate, Lactobacillus casei(L. casei) was considered better efficacy (0.04 (0.00, 0.77)) and medium tolerance (0.56 (0.19, 1.66)). Strain combination reported no superiority over single strain in either efficacy or tolerability.Conclusions LGG is probably the best option to consider when AAD is indicated. L. caseiappears to be the most efficacious choice when associated with severe C. difficile-related cases.

Probiotics are commonly used for the prevention of antibiotic-associated diarrhea (AAD). However, the optimum regimen remains controversial. The objective of this article is to compare and rank the relative efficacy and tolerability among all available probiotic agents for AAD through a network meta-analysis. Eligible studies were identified by searching PubMed, Embase, Medline, Cochrane library and Web of Science for randomized controlled trials (RCTs) that examined the efficacy of probiotic therapy for AAD. A random-effects model was applied within a frequentist framework. Quality of evidence was performed by the GRADE approach. The project was prospectively registered with PROSPERO (CRD 42016050776). Fifty-one articles (60 comparisons, 9569 participants), including 10 probiotic interventions, were identified. Lactobacillus rhamnosusGG (LGG) had the highest probability of being ranked best both in effectiveness (odds ratio (OR), 95% confidence interval (CI) = 0.28 (0.17, 0.47)) and tolerance (0.44 (0.23, 0.84)) on prevention of AAD. With regard to reducing Clostridium difficileinfection rate, Lactobacillus casei(L. casei) was considered better efficacy (0.04 (0.00, 0.77)) and medium tolerance (0.56 (0.19, 1.66)). Strain combination reported no superiority over single strain in either efficacy or tolerability. LGG is probably the best option to consider when AAD is indicated. L. caseiappears to be the most efficacious choice when associated with severe C. difficile-related cases.

The mixed dentition is often accompanied by transient malocclusions, such as a midline diastema. The general principle is to monitor development to ascertain the appropriate timing of possible intervention. The present clinical article reports the case of a seven-year-old boy who suffered from severe iatrogenic periodontitis of the maxillary incisors due to direct closure of a diastema by a rubber band. The incisors survived and exhibited periodontal and pulpal health at an eight-year review. Carefully-sequenced interdisciplinary management and co-operation, appropriate biomechanics aided by temporary anchorage devices, and a longterm follow-up are noted as key factors determining success when clinicians encounter such challenges.

In laser-induced thermal-crack propagation, thermal stresses control the crack propagation mode and the quality of the crack surface. In this article, the 1064-nm semiconductor laser as a volumetric heat source is used for symmetry and asymmetry cutting glass. One of the problems in laser asymmetry linear cutting glass with laser-induced thermal-crack propagation is the quality of the crack surface which gets worse than that in symmetry cutting. This study lays great emphasis on analyzing the effect of the focus position and shear stresses on the crack sectional shape in semiconductor laser asymmetry linear cutting glass. This article indicates the volumetric heat flux formula, which simulates the temperature distribution from the material above or below the focal point. The heat source should be positioned above the focal point. Optical microscope photographs of the crack surface and sectional shape are obtained to examine the surface quality which is explained from the results of the stress fields using the extended finite element method simulation. In asymmetry cutting, shear stress is parallel to the crack surface and perpendicular to the cutting direction, which makes the crack surface smooth but uneven.