Search

External cavity enhancing nonlinearity provides a powerful architecture for new lasing spectrum generations. However, its realizations are traditionally sophisticated with locking circuits required, limiting its wide applications. In this letter, we break this limit by devising the first optical locking MOPA laser, with seed source of a MOPA fiber laser self-injection locking to a high-quality (Q) nonlinear fiber resonator (NFR). The self-injection locking MOPA laser reaches a spectral linewidth of 3.9kHz at its maximum output power of 4.78W, which is $\sim 5.5\times 10 ^{\mathbf {2}}$ linewidth reduced from the free running state. An up to 50-nm bandwidth of four wave mixing (FWM) spectrum is generated from the NFR, at 4.78-W output power of the self-injection locking MOPA laser. Such locking regime is environmentally stable, owing to the frequency pulling effect of the locked seed source to the NFR. This work paves an all optical locking scheme for high power external cavity enhancing optical systems, which will benefits nonlinear spectrum generations in a more simple, high efficiency and high linewidth performance way.

The sensorless control of permanent magnet synchronous motor (PMSM) has issues of complex signal process, cumbersome system structure and parameter setting, etc. To eliminate these defects and reduce costs of computation, a sensorless control method based on specific voltage feed-forward decoupling (VFD) is proposed for the medium and high-speed regions. On the one hand, the proposed method utilizes a specific feed-forward voltage to decouple the d-q axis current, so that the output of current regulator directly contains the position error signal and rotor magnetic flux information, which simplifies the signal processing. On the other hand, the normalization of position error signal eliminates the influence of rotor speed and magnetic flux on the loop feed-forward gain of position estimation. With the proposed method, the rotor position and the rotor magnetic flux can be observed simultaneously and the process of parameter setting can be simplified. Moreover, to meet the engineering requirements, a full-speed sensorless control scheme combines IF control starting strategy with VFD is designed in this paper. The experimental results show that the sensorless method for the medium and high speed proposed in this paper has good dynamic and static performance, the observed result of rotor magnetic flux is accurate, and the designed sensorless control scheme for the full-speed region is simple and practical.

Nitrous oxide (N2O) is a potent greenhouse gas with various production pathways. N2O reductase (N2OR) is the primary N2O sink, but the distribution of its gene clades, typically nosZI and atypically nosZII, along urbanization gradients remains poorly understood. Here we sampled soils from forests, parks, and farmland across eight provinces in eastern China, using high-throughput sequencing to distinguish between two N2O-reducing bacteria clades. A deterministic process mainly determined assemblies of the nosZI communities. Homogeneous selection drove nosZI deterministic processes, and both homogeneous and heterogeneous selection influenced nosZII. This suggests nosZII is more sensitive to environmental changes than nosZI, with significant changes in community structure over time or space. Ecosystems with stronger anthropogenic disturbance, such as urban areas, provide diverse ecological niches for N2O-reducing bacteria (especially nosZII) to adapt to environmental fluctuations. Structural equation modeling (SEM) and correlation analyses revealed that pH significantly influences the community composition of both N2O-reducing bacteria clades. This study underscores urbanization’s impact on N2O-reducing bacteria in urban soils, highlighting the importance of nosZII and survival strategies. It offers novel insights into the role of atypical denitrifiers among N2O-reducing bacteria, underscoring their potential ecological importance in mitigating N2O emissions from urban soils.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to the epidermal growth factor precursor homologous domain A (EGF-A) of low-density lipoprotein receptor (LDLR) in the liver and triggers the degradation of LDLR via the lysosomal pathway, consequently leading to an elevation in plasma LDL-C levels. Inhibiting PCSK9 prolongs the lifespan of LDLR and maintains cholesterol homeostasis in the body. Thus, PCSK9 is an innovative pharmacological target for treating hypercholesterolemia and atherosclerosis. In this study, we discovered that E28362 was a novel small-molecule PCSK9 inhibitor by conducting a virtual screening of a library containing 40,000 compounds. E28362 (5, 10, 20 μM) dose-dependently increased the protein levels of LDLR in both total protein and the membrane fraction in both HepG2 and AML12 cells, and enhanced the uptake of DiI-LDL in AML12 cells. MTT assay showed that E28362 up to 80 μM had no obvious toxicity in HepG2, AML12, and HEK293a cells. The effects of E28362 on hyperlipidemia and atherosclerosis were evaluated in three different animal models. In high-fat diet-fed golden hamsters, administration of E28362 (6.7, 20, 60 mg·kg−1·d−1, i.g.) for 4 weeks significantly reduced plasma total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C) and PCSK9 levels, and reduced liver TC and TG contents. In Western diet-fed ApoE−/−mice (20, 60 mg·kg−1·d−1, i.g.) and human PCSK9 D374Y overexpression mice (60 mg·kg−1·d−1, i.g.), administration of E28362 for 12 weeks significantly decreased plasma LDL-C levels and the area of atherosclerotic lesions in en faceaortas and aortic roots. Moreover, E28362 significantly increased the protein expression level of LDLR in the liver. We revealed that E28362 selectively bound to PCSK9 in HepG2 and AML12 cells, blocked the interaction between LDLR and PCSK9, and induced the degradation of PCSK9 through the ubiquitin-proteasome pathway, which finally resulted in increased LDLR protein levels. In conclusion, E28362 can block the interaction between PCSK9 and LDLR, induce the degradation of PCSK9, increase LDLR protein levels, and alleviate hyperlipidemia and atherosclerosis in three distinct animal models, suggesting that E28362 is a promising lead compound for the treatment of hyperlipidemia and atherosclerosis.

The Narasaka–Heck reaction is one of the most straightforward methods for constructing pyrroline derivatives. Herein, we report a novel nickel-catalyzed three-component carbonylation reaction, which cleverly realizes the continuous construction of C(sp3)–N bonds and C(sp3)–C(sp2) bonds and effectively promotes the synthesis of acyl-substituted pyrroline derivatives. Furthermore, this strategy not only expands the conversion pathway of γ,δ-unsaturated oxime esters but also provides a new method for the synthesis of nitrogen-containing heterocyclic compounds.

The connectivity (valency) of building blocks for constructing 3D covalent organic frameworks (COFs) has long been limited to 4, 6, 8, and 12. Developing a higher connectivity remains a great challenge in the field of COF structural design. Herein, this work reports a hierarchical expansion strategy for making 16-connected building blocks to construct 3D COFs with sqc topology. The [16 + 2] construction achieved by condensation between a 16-connected carbazolyl dicyanobenzene-based building block (CzTPN) and linear diamino linkers (BD or Bpy) affords two 3D COFs (named CzBD COF and CzBpy COF). Furthermore, attributed to the well-organized donor–acceptor (D–A) heterojunction, the Ni chelated CzBpy COF (Ni@CzBpy COF) exhibits excellent performance for photoredox/Ni dual catalytic C(sp3)–C(sp2) cross-coupling of alkyltrifluoroborates with aryl halides, achieving a maximum 98% conversion and 94% yield for various substrates. This work developed the first case of high-connectivity COFs bearing 16-connected units, which is the highest connectivity reported until now, and achieved efficient photocatalysis applications, thus greatly enriching the possibilities of COFs.

Stock forecast is a crucial yet challenging task in modern quantitative trading. Given theoretical and investment merits, recently a variety of deep learning methods have been proposed for automatically simulating stock movements from historical time series. However, these methods typically follow the i.i.d. assumption that actually contradicts the complex trading environment. In reality, individual stocks often exhibit diverse volatility patterns, while macro market scenarios may also change over time, jointly resulting in distribution shifts and weak generalization. To combat these bottlenecks, in this paper we propose a new learning architecture called Personalized Temporal Embedding and Routing (PTER) to improve stock forecast by forming a relaxed weight-sharing paradigm. The key of PTER is introducing hypernetworks to guide tailoring target network parameters, such that stock time series are embedded adapting to multi-object multi-scenario data disparities. Specifically, in the encoding stage, PTER first captures hyper-knowledge characterizing the similarity and peculiarity of different stocks and market scenarios. The knowledge space is then projected onto the temporal parameter space, enabling the customization of protruded features from chaotic observation signals. In the inference stage, each sample is dispatched to orthogonal predictor heads to dynamically output expected returns based on market conditions. Through experiments on benchmark datasets spanning over five years on four of the world's largest exchange markets, we show that PTER improves the cumulative and risk-adjusted revenue performance by a significant margin.

This article proposes a novel deep-learning-based ORB-SLAM-feature filtering framework to monitor, detect the occurrence, and estimate the distance of early wildfire through an integrated design of image processing of aerial onboard visual-infrared sensor measurements and real-time navigation of an unmanned aerial vehicle (UAV). The proposed framework uses a DJI ZenMuse H20T onboard sensor integrating with both visual and infrared cameras mounted on a DJI M300 UAV. It consists of three main functional modules to support early wildfire fighting and management missions: 1) smoke and suspected flame segmentation based on an attention gate U-Net, which decreases false alarm and provides semantic information; 2) camera poses recovery based on a monocular SLAM algorithm and wildfire spot distance estimation based on a triangulation algorithm. With the estimated wildfire distance, camera poses, and global positioning system (GPS) information of the UAV, the suspected wildfire spot can be geo-located; 3) visual-infrared images registration based on a geometry model to forbid false detection and missing segmentation. Finally, independent indoor and outdoor experiments are conducted to verify the effectiveness of the proposed algorithms in the developed framework.

The technology of combining multiple emission centers to exploit white-light-emitting (WLE) materials by taking advantage of porous metal–organic frameworks (MOFs) is mature, but preparing undoped WLE MOFs remains a challenge. Herein, a pressure-treated strategy is reported to achieve efficient white photoluminescence (PL) in undoped [Zn(Tdc)(py)]nnanocrystals (NCs) at ambient conditions, where the Commission International del’Eclairage coordinates and color temperature reach (0.31, 0.37) and 6560 K, respectively. The initial [Zn(Tdc)(py)]nNCs exhibit weak-blue PL consisting of localized excited (LE) and planarized intramolecular charge transfer (PLICT) states. After pressure treatment, the emission contributions of LE and PLICT states are balanced by increasing the planarization of subunits, thereby producing white PL. Meanwhile, the reduction of nonradiative decay triggered by the planarized structure results in 5-fold PL enhancement. Phosphor-converted light-emitting diodes based on pressure-treated samples show favorable white-light characteristics. The finding provides a new platform for the development of undoped WLE MOFs.

A visible-light-induced radical cascade regioselective acylation/cyclization of 1,7-dienes with acyl oxime esters for the preparation of acylation polycyclic compounds via NCR-mediated C–C σ-bond cleavage is established. The transformation involves the cleavage of the C–C σ-bond in acyl oxime esters and selective addition of the electron neutral C═C bonds in 1,7-dienes for the synthesis of acyl polycyclic quinolinone derivatives, not the traditional seven-membered ring products. The strategy offers several advantages, including broad substrate tolerance, no need for bases, hyperstoichiometric radical initiators, and other auxiliaries.

The construction of isotypic high-nuclearity inorganic cages with identical pristine parent structure and increasing nuclearity is highly important for molecular growth and structure–property relationship study, yet it still remains a great challenge. Here, we provide an in situ growth approach for successfully synthesizing a series of new giant hollow polymolybdate dodecahedral cages, Mo250, Mo260-I, and Mo260-E, whose structures are growth based on giant polymolybdate cage Mo240. Remarkably, they show two pathways of nuclear growth based on Mo240, that is, the growth of 10 and 20 Mo centers on the inner and outer surfaces to afford Mo250and Mo260-I, respectively, and the growth of 10 Mo centers both on the inner and outer surfaces to give Mo260-E. To the best of our knowledge, this is the first study to display the internal and external nuclear growth of a giant hollow polyoxometalate cage. More importantly, regular variations in structure and nuclearity confer these polymolybdate cages with different optical properties, oxidative activities, and hydrogen atom transfer effect, thus allowing them to exhibit moderate to excellent photocatalytic performance in oxidative cross-coupling reactions between different unactivated alkanes and N-heteroarenes. In particular, Mo240and Mo260-Ewith better comprehensive abilities can offer the desired coupling product with yield up to 92% within 1 h.

A novel multiple-input–multiple-output (MIMO) slot antenna with dual-band self-decoupling characteristics is proposed. The operating principle of the proposed method is to obtain the proper equivalent characteristic impedance and proper equivalent electrical length by adjusting the width of the shared radiators. The radiators of the initial antenna consist of only two nested square ring slots, and they are widened by multiple structures to form the nonuniform radiators in the proposed antenna. It can be coupled fed by four microstrip lines, respectively, creating the dual collinear polarization. The initial antenna operates at 1.3–1.6 GHz in the low band (LB) while at 3.6–3.83 GHz in the high band (HB). The isolation ranges from 7–10 dB in LB and 10–14 dB in HB. The proposed antenna ranges from 1.20 to 1.88 GHz and from 3.52 to 3.90 GHz, and the isolations are improved to over 30 dB in LB and over 65 dB in HB, respectively. The nonuniform slot radiators have both decoupling and matching functions without additional components. The proposed antenna has the advantages of wideband, compact and high isolation.

We have successfully synthesized a series of bidentate ligands by utilizing 2-(trimethylsilyl)phenyl trifluorosulfonate as a precursor for the benzyl group. This method proceeded by inserting a polythiourea into the C═S π-bond, intramolecular ring proton migration, and ring opening. Salient features of this strategy are mild reaction conditions, a novel product structure, excellent stereochemistry, and a good functional group tolerance. Furthermore, a series of density functional theory calculations were performed to gain insights into the transfer mechanism.

A novel three-component cyclization carbonylation reaction of iodoarene-tethered propargyl ethers with amine and CO is reported. This palladium-catalyzed cascade reaction undergoes a sequence of oxidative addition, unsaturated bond migration, carbonyl insertion, and nucleophilic attack to deliver the benzofuran skeleton. Both aromatic amines and aliphatic amines could proceed smoothly in this transformation under one atm of CO.

The use of low‐intensity pulsed ultrasound (LIPUS) for promoting fracture healing has been Food and Drug Administration (FDA)‐approved since 1994 due to largely its non‐thermal effects of sound flow sound radiation force and so on. Numerous clinical and animal studies have shown that LIPUS can accelerate the healing of fresh fractures, nonunions, and delayed unions in pulse mode regardless of LIPUS devices or circumstantial factors. Rare clinical studies show limitations of LIPUS for treating fractures with intramedullary nail fixation or low patient compliance. The biological effect is achieved by regulating various cellular behaviors involving mesenchymal stem/stromal cells (MSCs), osteoblasts, chondrocytes, and osteoclasts and with dose dependency on LIPUS intensity and time. Specifically, LIPUS promotes the osteogenic differentiation of MSCs through the ROCK‐Cot/Tpl2‐MEK–ERK signaling. Osteoblasts, in turn, respond to the mechanical signal of LIPUS through integrin, angiotensin type 1 (AT1), and PIEZO1 mechano‐receptors, leading to the production of inflammatory factors such as COX‐2, MCP‐1, and MIP‐1β fracture repair. LIPUS also induces CCN2 expression in chondrocytes thereby coordinating bone regeneration. Finally, LIPUS suppresses osteoclast differentiation and gene expression by interfering with the ERK/c‐Fos/NFATc1 cascade. This mini‐review revisits the known effects and mechanisms of LIPUS on bone fracture healing and strengthens the need for further investigation into the underlying mechanisms.

Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especially after decades of fertilization. Here, we assess the contribution of the soil functionalities of carbon (C), nitrogen (N), and phosphorus (P) cycling to crop production and explore how soil organisms control these functionalities in a 33-year field fertilization experiment. The long-term application of green manure or cow manure produced wheat yields equivalent to those obtained with chemical N, with the former providing higher soil functions and allowing the functionality of N cycling (especially soil N mineralization and biological N fixation) to control wheat production. The keystone phylotypes within the global network rather than the overall microbial community dominated the soil multifunctionality and functionality of C, N, and P cycling across the soil profile (0–100 cm). We further confirmed that these keystone phylotypes consisted of many metabolic pathways of nutrient cycling and essential microbes involved in organic C mineralization, N2O release, and biological N fixation. The chemical N, green manure, and cow manure resulted in the highest abundances of amoB, nifH, and GH48genes and Nitrosomonadaceae, Azospirillaceae, and Sphingomonadaceae within the keystone phylotypes, and these microbes were significantly and positively correlated with N2O release, N fixation, and organic C mineralization, respectively. Moreover, our results demonstrated that organic fertilization increased the effects of the network size and keystone phylotypes on the subsoil functions by facilitating the migration of soil microorganisms across the soil profiles and green manure with the highest migration rates. This study highlights the importance of the functionality of N cycling in controlling crop production and keystone phylotypes in regulating soil functions, and provides selectable fertilization strategies for maintaining crop production and soil functions across soil profiles in agricultural ecosystems.

ABSTRACTAlthough alterations in the autophagy-lysosome pathway have been observed in the SARS-CoV-2 infection and invasion process since the outbreak of the coronavirus disease in 2019, the in-depth mechanism of autophagic and lysosomal reprogramming by SARS-CoV-2 has yet to be well identified. Our recent study unveiled a pivotal role played by the open reading frame 7a (ORF7a) protein in the SARS-CoV-2 genome, particularly in the modulation of macroautophagy/autophagy flux and function during viral infection and pathogenesis. Our study elucidated the underlying molecular mechanisms by which SARS-CoV-2 ORF7a intercepts autophagic flux, evades host autophagy-lysosome degradation, and accelerates viral infection and progeny germination. Furthermore, our study highlights that ORF7a can be a therapeutic target, and glecaprevir may hold potential as a drug against SARS-CoV-2 by targeting ORF7a. The key observations revealed in this study also contribute to a growing understanding of the function of SARS-CoV-2 ORF7a and the mechanisms underlying COVID-2019 treatment.

Cancer immunotherapy is a treatment method that activates or enhances the autoimmune response of the body to fight tumor growth and metastasis, has fewer toxic side effects and a longer-lasting efficacy than radiotherapy and chemotherapy, and has become an important means for the clinical treatment of cancer. However, clinical results from immunotherapy have shown that most patients lack responsiveness to immunotherapy and cannot benefit from this treatment strategy. The tumor microenvironment (TME) plays a critical role in the response to immunotherapy. The TME typically prevents effective lymphocyte activation, reducing their infiltration, and inhibiting the infiltration of effector T cells. According to the characteristic differences between the TME and normal tissues, various nanoplatforms with TME targeting and regulation properties have been developed for more precise regulation of the TME and have the ability to codeliver a variety of active pharmaceutical ingredients, thereby reducing systemic toxicity and improving the therapeutic effect of antitumor. In addition, the precise structural design of the nanoplatform can integrate specific functional motifs, such as surface-targeted ligands, degradable backbones, and TME stimulus-responsive components, into nanomedicines, thereby reshaping the tumor microenvironment, improving the body’s immunosuppressive state, and enhancing the permeability of drugs in tumor tissues, in order to achieve controlled and stimulus-triggered release of load cargo. In this review, the physiological characteristics of the TME and the latest research regarding the application of TME-regulated nanoplatforms in improving antitumor immunotherapy will be described. Furthermore, the existing problems and further applications perspectives of TME-regulated platforms for cancer immunotherapy will also be discussed.

Introduction: Cervical disc herniation (CDH) is the most common cause of cervical radiculopathy and causes persistent neck pain and neurological deficits. Collagenase chemonucleolysis has been successfully applied to treat lumbar disc herniation, which has a similar pathological mechanism to CDH. However, its application for CDH remains under-researched, and there is an even greater lack of high-quality clinical evidence. This study aims to evaluate the efficacy and safety of collagenase chemonucleolysis for treating CDH. Methods: Eligible patients with CDH underwent collagenase chemonucleolysis via anterior cervical intradiscal injection or epidural injection. The primary efficacy endpoint showed an excellent and good rate regarding the Odom criteria, which was not lower than the reference value (≥ 78%) at 6 months postoperatively. The secondary efficacy endpoints were the percentage reduction in Numeric Rating Scale (NRS) and Neck Disability Index (NDI) scores from baseline, which were not lower than the reference values (≥ 40%, ≥ 30%), and improvement in the 36-Item Short Form Health Survey (SF-36) score compared to the preoperative value. The pre- and postoperative CDH index of patients were also compared. Safety endpoints included the incidence of adverse events (AEs) and serious adverse events (SAEs). Results: An excellent and good rate regarding the Odom criteria 6 months postoperatively was 90.5% (133/147), which was significantly higher than 78% (P< 0.004, 95% confidence interval 85.7–95.2%). The reduction in NRS and NDI scores exceeded 40% (P< 0.001) and 30% (P< 0.001), respectively. The SF-36 scores at 3 months and 6 months postoperatively were significantly higher than those preoperatively (P< 0.001). A significant difference was observed in the pre- and postoperative CDH index (109.6 ± 119.1 vs. 70.8 ± 74.8, P< 0.001). The incidence of AEs was 22.5% (33/147), of which 97.8% were grade 1–2. No collagenase-related AEs and SAEs occurred. Conclusion: Collagenase chemonucleolysis treatment for CDH exhibited favorable efficacy and safety and may be a better choice for patients in whom conservative treatment is ineffective. Trial Registration: The trial was registered on www.Chictr.org.cn(ChiCTR2200063043).

High-resolution geophysical exploration is crucial for accurately understanding underground structures. In acoustic well logging, conventional methods for enhancing vertical resolution often rely on coherence-based subarray techniques. However, due to the degradation of semblance over short arrays, the estimated acoustic slowness typically lacks accuracy for small aperture resolutions. In this article, an acoustic array processing method based on super-virtual interferometry (SVI) is presented, aiming to achieve high-resolution slowness profiles from borehole logging data. First, a subarray extension technique is proposed to enhance semblance. Second, we extend the SVI-based acoustic array processing methods, which can generate redundant information for semblance calculation from limited observations. The principles and workflow of the method are detailed, and numerical experiments are conducted to demonstrate its advantages over traditional processing approaches. Field data processing results indicate that the proposed methods provide high-accuracy measurements of slowness to the subfoot level, capturing intricate details of variations in formation slowness. Furthermore, field applications demonstrate the method’s capability to process dipole flexural waves and effectively suppress extraction errors through dispersion, providing an alternative solution for the time-domain treatment of dispersive waves.

In this paper, we propose a new class of discontinuous Galerkin (DG) methods for solving 1D conservation laws on unfitted meshes. The standard DG method is used in the interior cells. For the small cut elements around the boundaries, we directly design approximation polynomials based on inverse Lax-Wendroff (ILW) principles for the inflow boundary conditions and introduce the post-processing to preserve the local conservation properties of the DG method. The theoretical analysis shows that our proposed methods have the same stability and numerical accuracy as the standard DG method in the inner region. An additional nonlinear limiter is designed to prevent spurious oscillations if a shock is near the boundary. Numerical results indicate that our methods achieve optimal numerical accuracy for smooth problems and do not introduce additional oscillations in discontinuous problems.

1060/7N01/1060 laminated composites with reliable bonding interfaces were successfully fabricated via single-pass hot rolling at 475 °C. The effects of layer thickness ratios on microstructure and mechanical property of synthesized laminates were studied using scanning electron microscope, transmission electron microscope and electron backscattered diffraction technique accompanied with hardness and tensile testing. Moreover, microstructure and mechanical property of DCR (direct cold rolling) and ACR (solution annealing and peak ageing plus cold rolling) samples were also explored. The results show that layer thickness ratios have little effect on microstructure of each layer in hot-rolled sheets, and their mechanical properties are consistent with theoretical predictions based on the rule of mixture. In comparison, extra heat treatment has no obvious effect on grain size of pure aluminium layers. However, smaller strip-like grains along with dispersed, finer precipitates are formed in 7N01 layer of ACR samples, leading to stronger grain refinement strengthening, precipitation strengthening and dislocation strengthening.

A novel quad-port shared-radiator slot antenna with broadband decoupling characteristics is proposed. The proposed slot antenna (PSA) has multiple electrical-current nulls for decoupling, formed by the cancellation of contrary characteristic modes (CMs) currents. The reduction of broadband mutual coupling can be achieved by changing the slot width at the four edges and corners of the original slot antenna (OSA). The −10 dB operating bandwidth is expanded from 28.6% on OSA to 69.7% on PSA. The isolations are only 7–9 dB on OSA but improved to better than 17 dB on PSA, even reaching a maximum of 25 dB. The total efficiency of PSA has a significant improvement compared to the OSA, and the envelope correlation coefficients of PSA are close to zero, far below the OSA. The good coincidence between the simulated and measured results confirms the correctness of the proposed method.

Continuous authentication, which provides identity verification using behavioral biometrics in an implicit and transparent manner, has shown potentials for protecting privacy. As the most common way of human-computer interaction, touch behavior pattern of each user has been proven distinctive and widely adopted for continuous authentication. However, most touch based solutions rely on the touchscreen signals obtained from high-level application programming interfaces, which are hard to characterize fine-grained appearance and contour profile of contact fingertips as well as dynamic sliding information in a touch gesture. In this paper, we propose a continuous authentication framework called CT-Auth, which leverages raw capacitive value collected from capacitive touchscreen on smartphone as a descriptor of touch behavior for authentication. Specifically, we first develop a three-dimensional convolution neural network model for capturing intra-gesture spatial-temporal feature and a structure extraction model for capturing structural information between moving fingertips of a touch gesture and touchscreen. A recurrent neural network based model is also applied for capturing temporal patterns among a sequence of touch gestures. To evaluate the effectiveness of our framework, we recruit 100 volunteers over 2 months and collect a large-scale dataset in the unconstrained conditions. Extensive experiments reveal that CT-Auth provides the state-of-the-art authentication accuracy.

In a permanent magnet synchronous motor (PMSM) drive system without voltage sensor, affected by the inverter non-linearities, there is a phase offset problem between the reconstructed voltage and the actual voltage. This phase offset increases as the switching frequency decreases, especially pronounced in subway permanent magnet traction systems operating at the hundreds of Hertz level. As a result, in the medium-to high-speed range, the estimated rotor position progressively advances ahead of the actual rotor position, accompanied by an increasing content of estimated speed harmonics. To address this issue, this paper proposes a sensorless control performance optimization strategy for low switching frequency permanent magnet drive systems. On the one hand, the position error compensation strategy of voltage phase advance adjustment is adopted to eliminate the phase offset between the actual voltage and the reconstructed voltage. On the other hand, the method of cascading the adaptive notch filter with the low-pass filter is used to eliminate the harmonic interference in the feedback current, so as to realize the harmonic suppression of the estimated speed. The experimental results have confirmed the effectiveness of the proposed optimization strategy, ultimately the position sensorless control of the PMSM drive system with the inverter switching frequency of 500 Hz was achieved, effectively optimizing the control performance at low switching frequencies.

An Ir–Zr intermetallic coating was prepared onto Re/Ir coated graphite through a pack cementation method. The microstructure, nanoindentation and ablation behaviors of the coating system were investigated. The Ir–Zr coating was about 20 μm thick and consisted of 4 intermetallic phases which showed a quasi-gradient transition in composition. Nanoindentation measurements indicated that most of the intermetallic phases had higher hardness but lower Young's modulus compared to pure iridium. By ablation test in a high-frequency plasma wind tunnel, the heat flux limit of the Ir–Zr coating was measured to be about 6.1 MW/m2, and the endurance time was about 100 s under this condition. The coating failed at ∼2240 °C during the ablation test when the iridium melted, but the unfused parts remained complete and in good adhesion with the iridium beneath. The average normal emissivity between 2 and 5 μm of the sample was measured to be ∼0.82 at around 2092 °C before failure, which was higher than pure iridium and bulk ZrO2.