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With the improvement in device manufacturing technology, the insulated gate bipolar transistor (IGBT) has been widely used in power electronic systems (PESs), such as power transmission, railway traction inverters, and aerospace. There is an urgent need for the accurate transient electrical model of IGBTs. Based on the improved understanding of the carrier transport process in the high-voltage IGBT during the turn-off stage, this article proposes a new analytical temperature-dependent model of the turn-off transient process for field-stop IGBTs that considers the drive circuit's influence. Compared with existing analytical models, the proposed model improves the accuracy of the description of transient electrical behavior by considering the influence of carrier recombination. Finally, the accuracy of the proposed model is verified by comparing the simulation results with the experimental data obtained by the double pulse test. The comparison results show that the proposed model can accurately simulate the turn-off behavior of high-voltage IGBTs. Compared with the existing analytical model, the accuracy of the proposed model is significantly improved.

Double perovskites, a class of ceramic oxides with unique crystal structures and diverse physical properties, show promise for various technological applications including solar cells, photodetectors, and light-emitting diodes (LEDs). Despite limited research on rare earth-doped double perovskites, leveraging their ultrahigh luminous efficiency to achieve bright yellow LED emission and addressing energy transfer challenges between Yb3+and Nd3+ions in double perovskite La2ZnTiO6with moderate phonon energy are explored in this work. Through phonon-assisted energy transfer, an ultrasensitive optical thermometer covering a wide temperature range is developed by utilizing the different temperature responses of Er3+emission in the visible light region and Nd3+emission in the near-infrared region based on the luminescence intensity ratio (LIR). All the results demonstrate that the rare earth (Yb–Er, Yb–Nd, and Yb–Nd–Er)-doped La2ZnTiO6phosphors can be effectively utilized for ultrabright LED illumination and ultrahigh sensitivity self-calibrated temperature sensing. This research underscores the significance of phonon-assisted energy transfer in improving material properties and provides valuable insights for the advancement of multifunctional materials.

Luminescence nanothermometers have garnered considerable attention due to their noncontact measurement, high spatial resolution, and rapid response. However, many nanothermometers employing single-mode measurement encounter challenges regarding their relative sensitivity. Herein, a unique class of tunable upconversion (UC) and downshifting (DS) luminescence covering the visible to near-infrared range (400–1700 nm) is reported, characterized by the superior Tm3+, Ho3+, and Er3+emissions induced by efficient energy transfer. The outstanding negative thermal expansion characteristic of ScF3nanocrystals has been found to guide excitation energy toward the relevant emitting states in the Yb3+–Ho3+–Tm3+-codoped system, consequently resulting in remarkable near-infrared III (NIR-III) luminescence at ∼1625 nm (Tm3+:3F4→ 3H6transition), which in turn presents numerous opportunities for designing multimode ratiometric luminescence thermometry. Furthermore, by facilitating phonon-assisted energy transfer in Er3+–Ho3+-codoped systems, the luminescence intensity ratio (LIR) of 4I13/2of Er3+and 5I6of Ho3+in ScF3:Yb3+/Ho3+/Er3+exhibits a strong temperature dependence, enabling NIR-II/III luminescence thermometry with superior thermal sensitivity and resolution (Sr= 0.78% K–1, δT= 0.64 K). These findings not only underscore the distinctive and ubiquitous attributes of lanthanide ion-doped nanomaterials but also hold significant implications for crafting luminescence thermometers with unparalleled sensitivity.

High-voltage insulated-gate bipolar transistors (IGBTs) have been extensively used in power electronic systems, such as railway traction inverters, flexible dc transmission systems, and wind turbines, and it is necessary to investigate transient modeling of high-voltage IGBTs. Based on the mechanism of the switching transient, this article proposes a new analytical model for the turn-off process of high-voltage IGBTs. First, considering the large base width of high-voltage IGBTs, the defect of the first-order approximation assumptions used in the existing model is analyzed in detail. Then, by using hyperbolic approximation, an improved solution method is developed for the transient ambipolar diffusion equation that considers the influence of carrier recombination in the base region. Finally, the accuracy of the proposed method is verified by comparing its simulation results with the experiment data obtained under the double pulse circuit. Results show that the proposed analytical model can more accurately simulate switching behaviors in the turn-off process.

This article presents new full-wave analytical formulas for the partial element involving the free-space Green's function in the modeling of thin-wire structures for lightning transient analysis. In the framework of the partial element equivalent circuit (PEEC) formulation for thin conductors, the partial elements are computed by double-folded line integrals. In layered media, the interaction integrals involve the dyadic Green's function, which contains the free-space Green's function term. The direct numerical computation of these integrals is time-consuming, which hinders the practical application of the full-wave method. Therefore, quasi-static (QS) analytical formulas for orthogonal meshes are widely used, which significantly reduces the computational overhead. However, these existing analytical formulas are derived under the QS hypothesis, which is not suitable for full-wave wideband analysis. The accurate analytical calculation of these partial elements has not been investigated in a comprehensive way so far. Accordingly, this article presents new full-wave analytical formulas for the evaluation of the partial elements for a thin-wire structure. These formulas are derived based on the Taylor series expansion of the full-wave free-space Green's function. The range of applicability of the proposed formulas is analyzed in terms of frequency, length of the conductor, and distance between these conductors. Numerical results computed by the PEEC method are presented, showing that the proposed formulas outperform the conventional QS ones at high frequencies, which makes them more appropriate for wideband modeling.

This article presents an efficient full-wave partial element equivalent circuit (PEEC) method of thin-wire structure in half-space for lightning transient analysis. In the framework of the PEEC formulation for thin-wire conductors, the partial elements are computed by double-folded line integrals. In layered media, the interaction integrals involve dyadic Green's functions, which contain a closed-form part and a Sommerfeld-integral part. The direct numerical computation of these integrals is very challenging and time-consuming, which hinders the practical application of the full-wave method. However, the efficient and accurate evaluation of partial elements has not been investigated in a comprehensive way so far. Accordingly, this article presents an efficient method for the evaluation of the partial elements between elementary segments in half space. The main novelty is that the interaction integrals are computed through a combination of the Taylor series expansion of the full-wave free space Green's function and the Sommerfeld-integral adaptive interpolation technique, which significantly reduces the computation time. The new method is systematically validated on examples from finite-difference time-domain (FDTD) method and method of moments and experimental results. The proposed method is validated with the NEC code in the frequency domain and the FDTD in the time domain.

This article presents an efficient full-wave partial element equivalent circuit (PEEC) formulation of thin-wire structure in the full space of air-homogeneous lossy ground for lightning transient analysis. First, the Green's functions for the case of an air-uniform ground are derived, which involve Sommerfeld-type integrals. Next, using the singularity subtraction technique, a new form of Green's functions is obtained, which has the advantage of being less singular and smooth compared with the original form. In the full-wave method, the efficient and accurate computation of partial elements is crucial for the practical application of the PEEC formulation. A three-dimensional cubic interpolation scheme is employed to accelerate the computation of Sommerfeld integrals. To improve the computational efficiency and accuracy of the interpolation, the continuity and symmetry of the Green's functions are investigated in a comprehensive way, which is important for a successful interpolation. Numerical and experimental examples from the literature are presented to validate the accuracy of the proposed model.

To meet the requirements of simulating the electric field during a lightning strike, there is an urgent need for a voltage pulse generator that generates voltage pulses that are equivalent to the electric field during the lightning strike. A new pulse generator structure based on a push–pull dc–dc converter and a flyback converter is proposed. The pulses produced by the proposed generator have a variable voltage rise rate, and a modular design is used for the generator. Each module works independently and is powered by an exclusive lithium battery, which avoids the problems of the need for a high-voltage dc source, current sharing, and a complex control strategy in existing generators. The electrical behavior of the proposed generator during the switching transient is analyzed considering the effects of both the semiconductor switching device (insulated-gate bipolar transistor) and transformer. The method of selecting the specifications of each component and the method of designing the core component are presented in this study. The accuracy of the transient model and the feasibility of the proposed generator are verified in experiments, and a 60-stage prototype that produces pulses with amplitudes in excess of 1 MV, widths of 1–3 ms, and a variable voltage rise rate is developed.

This paper presents a PEEC model of thin-wire structures for lightning grounding analysis based on low-frequency approximation of dyadic Green's functions. To avoid the time-consuming numerical Sommerfeld integrals, the primary and quasi-dynamic terms are extracted from the spectral-domain Green's function and used as the low-frequency approximation closed-form of the full-wave solution, which is appropriate in the near-field region. The corresponding equivalent circuit is constructed with this closed-form approximated Green's function and the formulas for the partial inductance and coefficient of potential is given. Comparison in terms of the Green's function and circuit parameters between the proposed method and the conventional modified-image method is made. The validity of the proposed method is confirmed with experimental results gathered from published literature and MOM-calculated results from other researchers. A systematic parametric analysis is conducted to evaluate the accuracy and applicability of the different approximate models, which clearly shows the superiority of the proposed method over the traditional modified-image method.

Electric field stress concentration is one of the causes of partial discharge (PD) in power modules, which threatens the power modules’ safe operation. Herein, this article investigates the influences of temperature (from 150 to $250~^{\circ }\text{C}$ ) and operation duration on the maximum electric field stress at the triple point (silicone elastomers, ceramic, and copper). It reveals that the maximum electric field stress rises with the increase in temperature, while the maximum electric field first increases but then decreases along the operation duration, especially under low temperature. Both the influences of temperature and the operation duration are related to the permittivity (dominated by the relaxation of Si–O bonds), low-frequency dispersion (LFD) phenomenon, and dc conductivities of silicone elastomers, which can be manipulated to suppress electric field stress concentration. This article provides a method to accurately calculate the electric field. The results are also critical to evaluation and improvement of power modules’ insulation.

Hybrid DC circuit breakers (DCBs) have recently been used to break short-circuit fault currents to ensure safety in flexible DC transmission projects. However, electromagnetic transients from DCB operation can interfere with the secondary equipment and cause malfunctions. In this paper, the bipolar short-circuit test, which is the first short-circuit test for DC transmission line in flexible DC project in the world, has been carried out in the 200 kV HVDC converter station equipped with two hybrid DCBs. The transient magnetic field near the secondary equipment in the DCB hall were measured, and its characteristics were discussed. Furthermore, the relationships among the space magnetic field, the short-circuit current and the action of the power electronic equipment in the DCB were also analyzed The main findings are as follows. During the bipolar short-circuit process, the maximum space magnetic field intensity near the secondary device is 109 A/m, and the maximum rising rate of the magnetic field waveform is about 350 A/m/ms. The magnetic field strength reached its peak value at the moment when the DCB was blocked, as well as the short-circuit current. It can be indicated that the DCB can cut off the short-circuit fault current accurately and reliably. The results can provide reference for the immunity evaluation and anti-interference protection of secondary equipment, and its optimal arrangement in the DCB hall.

If the follow-current interruption time of gas discharge tube is too long, it will lead to short circuit trip of equipment, even breakdown and damage. In order to mitigate the phenomenon and propose corresponding protective measures, the follow-current interruption characteristics of gas discharge tube are studied under different power frequency voltage amplitude and lightning phase polarity in this paper. Required by international standard IEC61000-4-5, the 1.2/50μsand 8/20μslightning surge combination waves are used to conduct impulse test on gas discharge tube. For the most rigorous experimental results, the method of series connection with varistor is used in order to suppress the follow-current phenomenon of gas discharge tube. Through the analysis of the experimental results, it is found that: the initial rising rate of voltage and follow-current interruption time are positively correlated with the power frequency voltage amplitude; the initial rising rate of voltage and follow-current interruption time increase in the first half cycle and decrease in the latter half cycle with the increase of the lightning pulse phase in each half power frequency cycle; the initial polarity of the follow-current glow voltage is consistent with the polarity of the lightning pulse, and the initial polarity of the follow-current arc voltage is consistent with the polarity of the power frequency period of the pulse; it can effectively suppress the follow-current phenomenon and reduce the residual voltage that using gas discharge tube in series with varistor whose voltage is less than its direct-current breakdown voltage. The conclusion of this paper has a certain guiding role for the parameter selection of gas discharge tube.

Vulnerability assessment of electronic devices excited by various transient electromagnetic disturbances (TEDs) has been a key issue in electromagnetic susceptibility research. This paper proposes a generalized vulnerability assessment method that includes acquiring data and building assessment model. The data is normally acquired by carrying out experiments, while the assessment model is mainly determined by prior information. As different devices under test (DUTs) could offer a different amount of prior information, a generalized assessment model consisting of a white-box model, a grey-box model, and a black-box model is built to deal with situations of sufficient prior information, partial prior information, and no prior information, respectively.

Nasopharyngeal cancer (NPC) is a malignant epithelial carcinoma of the head and neck. Cancer therapy targeting programmed cell death protein-1 (PD-1) or programmed death ligand-1 (PD-L1) is revolutionary. However, the tumorigenic mechanism of PD-L1 is not yet clear in NPC. Here we demonstrated an oncogenic role of PD-L1 via activating PI3K/AKT in NPC cells. PD-L1 overexpression was frequently detected in NPC biopsies and cell lines by qRT-PCR. PD-L1 overexpression and knockdown demonstrated that PD-L1 promoted NPC cell invasion and metastasis in vitro and in vivo. Mechanistically, PD-L1 prominently activated the epithelial‐mesenchymal transition (EMT) process in a PI3K/AKT-dependent manner. Taken together, we found that PD-L1 overexpression confers NPC cell malignancy and aggressiveness via activating the downstream PI3K/AKT signaling. Thus, these results provide a basis for diagnosis and treatment of NPC.

Soil drying-rewetting (DRW) events affect nutrient transformation and microbial community composition; however, little is known about the influence of drying intensity during the DRW events. Therefore, we analyzed soil nutrient composition and microbial communities with exposure to various drying intensities during an experimental drying-rewetting event, using a silt loam from a grassland of northern China, where the semi-arid climate exposes soils to a wide range of moisture conditions, and grasslands account for over 40% of the nation's land area. We also conducted a sterilization experiment to examine the contribution of soil microbes to nutrient pulses. Soil drying-rewetting decreased carbon (C) mineralization by 9%–27%. Both monosaccharide and mineral nitrogen (N) contents increased with higher drying intensities (drying to ≤ 10% gravimetric water content), with the increases being 204% and 110% with the highest drying intensity (drying to 2% gravimetric water content), respectively, whereas labile phosphorus (P) only increased (by 105%) with the highest drying intensity. Moreover, levels of microbial biomass C and N and dissolved organic N decreased with increasing drying intensity and were correlated with increases in dissolved organic C and mineral N, respectively, whereas the increases in labile P were not consistent with reductions in microbial biomass P. The sterilization experiment results indicated that microbes were primarily responsible for the C and N pulses, whereas non-microbial factors were the main contributors to the labile P pulses. Phospholipid fatty acid analysis indicated that soil microbes were highly resistant to drying-rewetting events and that drought-resistant groups were probably responsible for nutrient transformation. Therefore, the present study demonstrated that moderate soil drying during drying-rewetting events could improve the mineralization of N, but not P, and that different mechanisms were responsible for the C, N, and P pulses observed during drying-rewetting events.

The physiology of a cell can be viewed as the product of thousands of proteins acting in concert to shape the cellular response. Coordination is achieved in part through networks of protein–protein interactions that assemble functionally related proteins into complexes, organelles, and signal transduction pathways. Understanding the architecture of the human proteome has the potential to inform cellular, structural, and evolutionary mechanisms and is critical to elucidating how genome variation contributes to disease. Here we present BioPlex 2.0 (Biophysical Interactions of ORFeome-derived complexes), which uses robust affinity purification–mass spectrometry methodology to elucidate protein interaction networks and co-complexes nucleated by more than 25% of protein-coding genes from the human genome, and constitutes, to our knowledge, the largest such network so far. With more than 56,000 candidate interactions, BioPlex 2.0 contains more than 29,000 previously unknown co-associations and provides functional insights into hundreds of poorly characterized proteins while enhancing network-based analyses of domain associations, subcellular localization, and co-complex formation. Unsupervised Markov clustering of interacting proteins identified more than 1,300 protein communities representing diverse cellular activities. Genes essential for cell fitness are enriched within 53 communities representing central cellular functions. Moreover, we identified 442 communities associated with more than 2,000 disease annotations, placing numerous candidate disease genes into a cellular framework. BioPlex 2.0 exceeds previous experimentally derived interaction networks in depth and breadth, and will be a valuable resource for exploring the biology of incompletely characterized proteins and for elucidating larger-scale patterns of proteome organization.

The close relationship between RNA structure and function underlines the significance of accurately predicting RNA structures from sequence information. Structural topologies such as pseudoknots are of particular interest due to their ubiquity and direct involvement in RNA function, but identifying pseudoknots is a computationally challenging problem and existing heuristic approaches usually perform poorly for RNA sequences of even a few hundred bases. We survey the performance of pseudoknot prediction methods on a data set of full-length RNA sequences representing varied sequence lengths, and biological RNA classes such as RNase P RNA, Group I Intron, tmRNA and tRNA. Pseudoknot prediction methods are compared with minimum free energy and suboptimal secondary structure prediction methods in terms of correct base-pairs, stems and pseudoknots and we find that the ensemble of suboptimal structure predictions succeeds in identifying correct structural elements in RNA that are usually missed in MFE and pseudoknot predictions. We propose a strategy to identify a comprehensive set of non-redundant stems in the suboptimal structure space of a RNA molecule by applying heuristics that reduce the structural redundancy of the predicted suboptimal structures by merging slightly varying stems that are predicted to form in local sequence regions. This reduced-redundancy set of structural elements consistently outperforms more specialized approaches.in data sets. Thus, the suboptimal folding space can be used to represent the structural diversity of an RNA molecule more comprehensively than optimal structure prediction approaches alone.

In order to measure accurately position of object in remote large area with vision measurement method, a special layout of vision measurement system was designed. Some calibration objects which have the same height with cameras were placed at specific position in the measurement area. By adjusting carefully the posture of cameras, those calibration objects were imaged at the same pixel row which contained the camera principal point. As a result, the master planes of cameras which were determined by the pixel row which contained the principal point and the optical axis of cameras were horizontal and coplanar. So, the u pixel coordinate of any space point was same with the one of its projection point in the xoy coordinate plane and a simplified calculation model was derived. Compared with the traditional vision measurement method, this method is simpler and more suitable for large remote area measurement. In order to verify the validity of this method, a verification experiment had been made. The experimental results show that the resolving accuracy of this model is very high, and this measurement method is very good to meet the requirement of large remote area measurement.

AbstractThis paper presents a teleoperated robot hand system with haptic tactile feedback. This system enables an operator to control amulti-fmgered robot hand while feeling interactions of the robot hand with the remote environrent. We have designed a fingertip tactile sensor to capture high resolution and quality tactile images between the fmgertip and the environrent based on the optical total reflection principle. In order to feed back the tactile information to the operator, an electrotactile glove and a haptic display with 24 pins driven by structured DC solenoids have been developed. The haptic glove generates excitations when atouch/contact between the fingertips and the environment occurs. The tactile display can present contact points on the fmger tips. We have integrated the tactile sensor, the haptic glove and the tactile display into afive-fingered hand system and examined their performance and effectiveness by experiments.

By alloy melting, microstructure analysis and micro-hardness test, the effects of Sm addition on the microstructure of Mg-12Gd-2Y-0.5Zr alloy with solution treatment and aging treatment were investigated. The results showed that the microstructure of the tested alloy consisted of a-Mg matrix, Mg41Sm5, Mg5Gdm, Mg24Y5 and b' phases, and Sm improved the micro-hardness value of a-Mg matrix attributed to its better solid solution strengthening effect in a-Mg. The micro-hardness of the alloy with Sm increases obviously from HV121.4 to HV134.3 when compared with that of Mg-12Gd-2Y-0.5Zr alloy.

Combining a phenotypic screen with chemoproteomics reveals CDK12 as a potential therapeutic target to inhibit noncanonical NF-κB in inflammation and cancer.

Laser image often contains mixed noise mainly including salt and pepper noise and Gaussian noise. Not only the quality of laser image is made deteriorated but also the important details of laser image are flooded by it. A new mixed noise filtering method for laser image is proposed in this paper to filter out mixed noise effectively meanwhile ensure laser image details clear and completed. In the first space, salt and pepper noise in laser image is filtered out in spatial domain. A Novel Adaptive Switching Median (NASM) filter based on local salt and pepper noise density which determines filter window of every salt and pepper noise point adaptively is introduced here. Secondly, image is transferred to wavelet domain to filter out Gaussian noise. Local Adaptive BayesShrink Threshold (LABT) wavelet denoising on basis of Gaussian Mixture Model (GMM) is used in this step where wavelet coefficients are modeled by GMM and LABT is used for adjusting the threshold adaptively which utilizes local relevant characters of sub band wavelet coefficients. Experimental results show that new method can remove mixed noise effectively meanwhile protect details of laser image well thus getting better filtering performance compared with other filters for laser image.