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In this article, a temperature stabilization method of high-temperature reverse bias (HTRB) and high-voltage high-temperature high-humidity reverse bias (HV-H3TRB) tests for 6.5 kV high-voltage power IGBT modules used in railway is proposed. The traditional climate chamber is not suitable for stabilizing the temperature of high-voltage IGBT modules, as there are multi-chips connected in parallel, which can create a high leakage current during the high-voltage blocking state at high junction temperature. The proposed junction temperature stabilization method can avoid thermal runaway caused by positive feedback between power loss and junction temperature in HTRB and HV-H3TRB tests, and the effectiveness is confirmed by experimental results. Furthermore, a precise junction temperature measurement method based on leakage current is proposed, which can be used to set initial junction temperature correctly for HTRB and HV-H3TRB tests.

Cellulose aerogel fibers (CAFs) which have a porous nanonetwork and fiber geometry are promising candidates for thermal insulation or flexible devices due to their excellent thermophysical properties, renewability, and cost-effectiveness. However, their weak skeletal structure, low mechanical strength, combustibility, and poor moisture resistance remain significant barriers to their commercial viability. The establishment of physical and chemical cross-links is a potential strategy to enhance the strength, toughness, and overall performance of aerogels. In this work, interconnected networks of cellulose-based aerogel fibers are fabricated through continuous coagulation spinning and modified with the addition of 4,4′-methylene diphenyl diisocyanate (MDI) as the cross-linker. The CAFs modified with 1.5 wt % of MDI have good tensile strength (27.7 MPa), an ultrahigh Young’s modulus (735 MPa), and excellent bending resistance even after they are knotted or looped for the tensile tests. The fabric made with MDI-modified CAFs is lightweight and flexible and has humidity insensitivity, with a better thermal conductivity of 0.09 in a 98% humidity environment compared with pristine CAFs. Significantly, the insulation of this fabric is almost the same as cotton wadding, yet only 1/5 of its thickness (RH = 50–60%). In addition, different functionalized aerogel fibers have been fabricated, such as those that are colored, antibacterial, and flame-retardant. The study shows the huge potential of cellulose-based aerogel fibers and textiles in producing the next generation of biomass-based high-performance thermal insulating devices.

Tumor penetration is a critical determinant of the therapy efficacy of nanomedicines. However, the dense extracellular matrix (ECM) in tumors significantly hampers the deep penetration of nanomedicines, resulting in large drug-untouchable areas and unsatisfactory therapy efficacy. Herein, we synthesized a third-generation PAMAM-cored multiarm copolymer and modified the polymer with collagenase to enhance its tumor penetration. Each arm of the copolymer was a diblock copolymer of poly(glutamic acid)-b-poly(carboxybetaine), in which the polyglutamic acid block with abundant side groups was used to link the anticancer agent doxorubicin through the pH-sensitive acylhydrazone linkage, and the zwitterionic poly(carboxybetaine) block provided desired water solubility and anti-biofouling capability. The collagenase was conjugated to the ends of the arms viathe thiol-maleimide reaction. We demonstrated that the polymer-bound collagenase could effectively catalyze the degradation of the collagen in the tumor ECM, and consequently augmented the tumor penetration and antitumor efficacy of the drug-loaded polymers.

Insufficient attenuation and poor heat dissipation in the beam-wave interaction section are critical limitations in developing the megawatt-level gyrotron traveling wave tube (gyro-TWT). To solve these problems, we propose a water-based lossy waveguide with high attenuation and heat dissipation in this letter. It comprises a vacuum region, a lossless BeO ceramic, and flowing water. Measured results indicate that the proposed structure can achieve an attenuation higher than 10dB/cm at 15.5-17.0GHz. The maximum attenuation at 16.3GHz can even exceed 29dB/cm. It is sufficient to suppress oscillations at large currents. In addition, the flowing water has a higher power capacity than conventional lossy dielectric. The proposed structure paves the way for the development of megawatt gyro-TWTs.

This letter presents an approach to generate the sub-nanosecond microwave pulse with a high power compression factor using a compact reflection structure. In the experiment, an input chirped pulse with the frequency nonlinearly sweeping from 12.03 to 15.53 GHz is compressed, and the generated pulse has a 3 dB pulse width of 0.257 ns and a power compression factor of 43.3. The experimental result is in good agreement with our simulation. This method can potentially enhance the power level of broadband vacuum electron amplifiers.

Rotating ships usually suffer from complicated defocusing in high-resolution spaceborne synthetic aperture radar (SAR) imagery due to the nonuniform motions, which severely restricts the classification and interpretation of ships in SAR applications. In this article, a novel refocusing method is proposed to improve the imaging quality of rotating ships by postprocessing SAR imagery. We first attempt to utilize the nonlinear chirp scaling (NLCS) principle to correct space-variant phase errors induced by target rotations. Specifically, an azimuth inverse compression approach without zero-padding operation is designed to recover the azimuth frequency modulation (FM) of the target image data. Then, a modified NLCS operation is derived for space-variant phase error correction by introducing a high-order perturbation function. An objective function based on image quality is also constructed to estimate the optimal perturbation parameters. Finally, simulated data and real spaceborne SAR data are processed to demonstrate the good performance of the proposed method in comparison with other state-of-the-art techniques.

Processing high-squinted spaceborne SAR data in the sliding-spotlight mode is a challenging task due to azimuth spectral aliasing and range-azimuth coupling for frequency-domain imaging algorithms, and most critically, the variation of Doppler parameters causes significant reduction in the depth-of-azimuth-focus (DOAF). In this article, a novel imaging algorithm is proposed for focusing high-squinted spaceborne SAR data in the sliding-spotlight mode. First, linear range walk correction (LRWC) and range frequency-dependent derotation are applied to remove the coupling of range frequency with the Doppler parameters. Then, a modified range migration algorithm (RMA) is derived for accurate focusing. The deramp operation combined with improved nonlinear chirp scaling (INCS) is employed for solving the aliasing problem of azimuth time and extending the DOAF in the third step. Finally, geometry distortion caused by LRWC is corrected. Simulation results are provided to demonstrate the effectiveness of the proposed algorithm.

The malfunction of an insulated gate bipolar transistor (IGBT) device can result in the failure and damage of both itself and the system in which it is installed, and various types of faults in the device typically lead to changes in its impedance characteristics. This article leverages the advantages of travelling wave reflectometry in the field of identifying characteristic impedance parameters of devices, and conducts device-level research on the transmission and reflection response characteristics of sequence/spread spectrum time domain reflectometry (STDR/SSTDR) signals for IGBT. On the one hand, based on a clear understanding of the aliasing patterns and their impacts on reflected signals, this article proposes a signal pre-processing algorithm using a time-domain signal transmission analytical model to reduce identification errors introduced by aliasing phenomena. On the other hand, based on establishing the mapping relationship between the characteristic parameters of various IGBTs and their different fault states, this article proposes an IGBT fault diagnosis method based on characteristic parameters identification of time-domain reflection signals. Compared to traditional methods, the proposed method can achieve nonintrusive fault detection for both IGBT and antiparallel diode simultaneously, and has the flexibility to adjust the testing conditions. Finally, relevant experiments were conducted to verify the proposed method, and the expected results were achieved.

When the rotor is rotating at high speed, magnetically suspended control and sensitive gyroscope (MSCSG) will generate synchronous and multifrequency vibration due to rotor mass unbalance and sensor runout, which will affect the measurement accuracy of output torque and attitude angular velocity. In order to suppress the above unbalanced vibration, first, the dynamic model of MSCSG with unbalance vibration torque is established, and the influence of unbalance vibration on the measurement accuracy of attitude angular velocity is analyzed. Then, combined with the strong coupling characteristics of two tilt channels, an unbalance vibration suppression method based on arsinh function of normalized variable step size LMS (arsinh-NLMS) algorithm is proposed, which can adjust the step size according to different frequency components to improve the convergence rate. The arsinh function is used to ensure that there is a small error in the steady-state and the normalization process reduces the sensitivity of the algorithm to the input signal and tracks the harmonic components of the control current better. Finally, the simulation and experimental results show that the proposed method can effectively suppress the synchronous and multifrequency disturbance currents and vibration torques in MSCSG and reduce the influence of unbalance vibration on MSCSG performance and angular velocity measurement accuracy.

•Establishment of 3D cardiac organoids composed of cardiomyocyte and endothelial layers.•SARS-CoV-2 infection causes multi-lineage cardiac injuries.•Cardiovascular health should be greatly concerned in COVID-19 patients.

This study was conducted to evaluate the effects of dietary crude protein (CP) and rumen-protected lysine (RPL) supplementation on lactation performance, amino acid (AA) balance, nitrogen (N) utilization and hindgut microbiota in dairy cows. Treatments were in a 2 × 2 factorial arrangement, and the main effects were CP concentration (16% vs. 18%) and RPL supplementation (with or without RPL at 40 g/cow per day). Forty cows were randomly allocated to 4 groups: low-CP diet (LP), low-CP diet plus RPL (LPL), high-CP diet (HP), high-CP diet plus RPL (HPL). The experiment was conducted for 8 weeks. Results showed that RPL increased the dry matter intake (P < 0.01), milk protein yield (P = 0.04) and energy corrected milk (P = 0.04), and tended to increase milk fat yield (P = 0.06) and fat corrected milk (P = 0.05). Cows in the HP group tended to have higher milk urea N (P = 0.07). Plasma concentrations of Arg, Ile, Lys, Met, Pro, total essential AA and total nonessential AA were increased by RPL (P < 0.05). The total essential AA, total nonessential AA and most AA (except Ile, Phe, Gly and Pro) were increased in the HP group (P < 0.05). N excretion was increased in the HP group through an increase in urea N excretion (P < 0.01) and an upward trend in plasma urea N (P = 0.07). In addition, RPL tended to increase milk protein N secretion (P = 0.08), milk N (P = 0.07) and microbial protein synthesis (P = 0.06), and decreased plasma urea N (P < 0.001). In the hindgut, the bacterial community were different between the LP and LPL groups (P < 0.01). The probiotic abundances of Christensenellaceae_R-7_groupand Acinetobacterwere increased by RPL (P = 0.03 and 0.03, respectively). The pathogenic abundances of Clostridium_sensu_stricto_1(P < 0.001) and Turicibacter(P < 0.01) were decreased by RPL. In conclusion, supplementing RPL with low dietary CP could balance AA supply and increase milk protein yield, resulting in an improvement in N utilization efficiency, and altered the composition of the hindgut microbiota to favor the lactation performance of dairy cows.

The behavior of giant amphiphilic molecules at the air–water interface has become a subject of concern to researchers. Small changes in the molecular structure can cause obvious differences in the molecular arrangement and interfacial properties of the monolayer. In this study, we have systematically investigated the interfacial behaviors of the giant amphiphilic molecules with different number of hydrophobic BPOSS blocks and one hydrophilic ACPOSS block ((BPOSS)n-ACPOSS (n= 1–5)) at the air–water interface by the surface pressure–area (π–A) isotherm, Brewster angle microscopy (BAM), compression modulus measurement, and hysteresis measurement. We found that both the number of BPOSS blocks and the compression rate can significantly influence the interfacial behaviors of giant molecules. The π–Aisotherms of giant molecules (BPOSS)n-ACPOSS (n= 2–5) exhibit a “cusp” phenomenon which can be attributed to the transition from monolayer to multilayer. However, the cusp is dramatically different from the “collapse” of the monolayer studied in other molecular systems, which is highly dependent on the compression rate of the monolayer. In addition, the compression modulus and hysteresis measurements reveal that the number of BPOSS blocks of (BPOSS)n-ACPOSS plays an important role in the static elasticity, stability, and reversibility of the Langmuir films.

Aerogel fiber has emerged recently for incorporation in personal thermal management textiles due to its flexibility, scalability, and ultrahigh porosity, which allows the body to keep warm via thermal isolation without energy consumption. However, the functionalization and intellectualization of cellulose-based aerogel fibers have not yet been fully developed. Herein, we propose a biomimicking design inspired by polar bear and Siamese cat hair that combines porous cellulose aerogel fiber (CAF) with reversible thermochromic microcapsules to mimic biological sensory and adaptive thermoregulation functions. The produced CAF has a controllable pore structure, a large specific surface area (230 m2/g), and excellent mechanical strength (∼15 MPa). Low-temperature darkening microcapsules have been incorporated into the robust CAF to spontaneously adjust color by perceiving the ambient temperature. The functional aerogel fiber fabric achieves high thermal insulation and photothermal modulation simultaneously at temperatures below 18 °C. The temperature of the thermochromic fabric was higher by 6 °C than that of the sample without the microcapsules at a light intensity of 0.2 W/cm2. In addition, the aerogel fibers mixed with two types of thermochromic microcapsules exhibit three color switches with fast response, a color-control precision of 0.2 °C, and good cycling performance. This smart aerogel fibers hold great promise for self-adaptive thermal management, temperature indication, information transfer, and anticounterfeiting in textiles.

The current literature has deepened our understanding of the participation-job satisfaction relationship in public organizations. However, employee participation has various forms and each form may produce different effects on job satisfaction. The literature often fails to account for the effects of different forms of participation. This article fills this gap by specifically examining the effects of informal participation and the possible moderating effects of interpersonal relationships and career development support. Based on a survey of civil servants in Beijing, the article finds that informal participation has positive and statistically significant influence over job satisfaction. The effects are positively moderated by interpersonal relationships and negatively moderated by career development support. The results help us to gain a fine-grained understanding of the effects of informal participation and may serve as a starting point for more research on different forms of employee participation. Keywords job satisfaction, employee participation, informal participation, participative management, China, Introduction Employee participation, which is defined as the involvement of employees in information processing, decision making, and problem solving (Wagner, 1994), has been an important topic in management research. Though [...]

Elastomers with environmental adaption have attracted considerable attention for advanced applications in various areas. Here, we fabricate an ambient environment adaptive elastomer by assembling triblock copolymers polystyrene-b-poly(acrylic acid)-b-polystyrene (SAS) and polystyrene-b-poly(ethylene oxide)-b-polystyrene (SES). Owing to the microphase separation of triblock polymers and hydrogen-bonding complexation of their middle segments, the SAS/SES complex presents dichotomy of vitrified hard PS domains and soft PAA/PEO domains, which presents major relaxation transition in the temperature zone 10–30 °C and relative humidity (RH) 40–60%. The SAS/SES elastomer presents quick adaption to the ambient environment change with temperature and humidity coupling. Moreover, after a loading-unloading cycle training, the SAS/SES elastomer exhibits domain orientation, low energy dissipation, high recovery ratio, and distinct strain stiffening compared with the pristine complex. The SAS/SES elastomer has potential to be used as a sensing and adaption component for complicated intelligent systems.

Alcoholic liver injury (ALI) is the leading cause of serious liver disease, whereas current treatments are mostly supportive and unable to metabolize alcohol directly. Here we report a metabolic reprogramming strategy for targeted alcohol detoxification and ALI management based on a confined cascade nanoreactor. The nanoreactor (named AA@mMOF) is designed by assembling natural enzymes of alcohol oxidase (AOx) and aldehyde dehydrogenase (ALDH) in the cavity of a mesoporous metal organic framework (mMOF) nanozyme with intrinsic catalase (CAT)-like activity. By conducting confined AOx/CAT/ALDH cascade reactions, AA@mMOF enables self-accelerated alcohol degradation (>0.5 mg·mL–1·h–1) with negligible aldehyde diffusion and accumulation, reprogramming alcohol metabolism and allowing high-efficiency detoxification. Administered to high-dose alcohol-intoxicated mice, AA@mMOF shows surprising liver targeting and accumulation performance and dramatically reduces blood alcohol concentration and rapidly reverses unconsciousness and acute liver injury to afford targeted alcoholism treatment. Moreover, AA@mMOF dramatically alleviates fat accumulation and oxidative stress in the liver of chronic alcoholism mice to block and reverse the progression of ALI. By conducting confined AOx/CAT/ALDH cascade reactions for high-efficiency alcohol metabolism reprogramming, AA@mMOF nanoreactor offers a powerful modality for targeted alcohol detoxification and ALI management. The proposed confined cascade metabolic reprogramming strategy provides a paradigm shift for the treatment of metabolic diseases.

Multidrug-resistant bacteria caused by the unlimited overuse of antibiotics pose a great challenge to global health. An antibacterial method based on reactive oxygen species (ROS) is one of the effective strategies without inducing bacterial resistance. Owing to the ability of generating ROS, piezocatalytic material-mediated sonodynamic therapy (SDT) has drawn much attention. However, its major challenge is the low ROS generation efficiency in the piezocatalytic process due to the poor charge carrier concentration of piezoelectric materials. Vacancy engineering can regulate the charge density and largely promote ROS generation under ultrasound (US) irradiation. Herein, a US-responsive self-doped barium titanate with controlled oxygen vacancy (Vo) concentrations was successfully synthesized through a facile thermal reduction treatment at different temperatures (i.e., 350, 400, and 450 °C), and the corresponding samples were named as BTO-350, BTO-400, and BTO-450, respectively. Then, the effect of Vo concentrations on ROS generation efficiency during the piezocatalytic process was systematically studied. And BTO-400 was found to possess the highest piezocatalytic activity and excellent sonodynamic antibacterial performance against Escherichia coliand Staphylococcus aureus.Furthermore, its antibacterial mechanism was confirmed that the ROS generated under US could damage bacterial cell membrane and cause considerable leakage of cytoplasmic components and irreversible death of bacteria. Notably, the in vivo results illustrated that the BTO-400 could serve as an effective antibacterial agent and accelerate skin healing via SDT therapy. In all, the Vo defect-modified nano-BaTiO3has a noticeable potential to induce a rapid and efficient sterilization as well as skin tissue repair by SDT.

To realize the full-frequency angular rate measurement of spacecraft based on magnetically suspended control and sensing gyroscope (MSCSG), a full-frequency angular rate measurement method of spacecraft based on multi-MSCSG weight assignment is proposed in this article. First, the main structure of MSCSG is introduced. The traditional angular rate sensing principle of MSCSG is analyzed on the basis of the working principle of Lorentz magnetic bearing, the key component of MSCSG. After introducing and analyzing the shortcomings of the two existing measurement methods, namely, four-cross configuration and virtual gyro technology, the weight function of frequency is obtained by deriving the measurement accuracy model of the two methods. The weight assignment measurement method is proposed to achieve the fusion of the advantages of the two methods and achieve high-precision angular rate measurement of spacecraft in the full-frequency band. Through simulation and semi-physical experiments, we verified that the angular rate accuracy of spacecraft measured by the proposed one can be maintained above 98% at different frequencies, and the higher the frequency, the higher the angular rate measurement accuracy of spacecraft.

In this letter, we report the KrF excimer laser annealing for achieving high-performance ferroelectric Hf0.5Zr0.5O2(HZO). The laser anneals the target device layer effectively with a high heating/cooling rate without overheating under-layer deep structures. The impact of laser fluence, number of pulses, and pulse duration on the ferroelectricity in HZO was carefully studied through numerical simulation and experiment. The remnant polarization $2{P}_{\text {r}}$ of $22~\mu \text{C}$ /cm2, a coercive field of ~1 MV/cm, and a cycling endurance of > $10^{{8}}$ were achieved in the 8 nm ferroelectric HZO thin film annealed by the laser with an ultra-low laser fluence of ~84 mJ/cm2 and 20 pulses. Benefiting from the large beam size of KrF excimer laser, the laser annealing is practical for obtaining stable wafer-scale ferroelectric HZO within a short time.

The development of electric and connected vehicles as well as automated driving technologies are key towards the smart city, providing convenient urban mobility and high energy economy performance. However, the global rise in electricity price provokes renewed interest on CAVs with hybrid electric powertrains rather than considering battery electric powertrains. This paper proposes a decentralized coordination strategy for a group of connected and autonomous vehicles (CAVs) with a series hybrid electric (sHEV) powertrain at urban signal-free intersections. The problem is formulated as a convex form with suitable relaxation and approximation of the powertrain model and solved by decentralized model predictive control (DMPC), which enables rapid search and a unique solution in real-time. Numerical examples validate the effectiveness of the proposed methods concerning physical and safety constraints. By utilizing the petrol fuel and battery charging prices over the last year, the performance of the proposed approach is evaluated against the optimal results produced by two benchmark solutions, conventional vehicles (CVs) and battery electric vehicles (BEVs). The comparison results demonstrate that the traveling cost of sHEVs approaches and, even under some circumstances, reaches the same level as for BEVs, which indicates the importance of hybridization, particularly under the current rising electricity price situation.

Mode distortion and performance degradation caused by an OFF-axis gyrating electron beam in our W-band gyrotron traveling wave tube (gyro-TWT) were studied by the particle-in-cell (PIC) simulation and verified with the hot test experiments. The simulated electron beam misalignment may lead to a mixed pattern, mainly composed of TE01, TE02, TE21, and TE22 modes. They will further deteriorate the performance by disturbing the bunched electron beam. When the misalignment is over 0.1 mm, the operating mode shows a significant distortion, and the output power is reduced to 66% of that without misalignment at 93 GHz. For the prototype gyro-TWT with an estimated beam misalignment of about 0.1 mm, the measured saturated output power drops by more than 57% below 93.5 GHz compared with the normal one, whose estimated misalignment is less than 0.05 mm. The downward trend proves that the beam misalignment is the main factor causing the performance degradation at the W-band and above.

For the sake of achieving the high-accuracy and high-bandwidth attitude measurement and control integration of flexible spacecraft, an integrated method based on a novel configuration of variable speed magnetically suspended control and sensitive gyroscope (VSMSCSG) and radial basis function (RBF) neural network control is proposed in this article. First, the structure and principle of a novel VSMSCSG configuration are given, and its modeling is established. VSMSCSGs are employed as both actuators and attitude-rate sensors. Second, the attitude measurement method based on the configuration is proposed in the case of rotor spin speed and deflection angle changing. Based on the characteristics of the novel configuration, the corresponding RBF neural network attitude control law of spacecraft and the adaptive saturation avoidance steering laws of the VSMSCSGs have been further designed; the rotor can deflect at high frequency and change speed simultaneously to output a high bandwidth attitude control moment which dramatically improves the moment output capability of VSMSCSG configuration. Compared with the traditional method of attitude measurement and control integration, the proposed one not only improves the speed and accuracy of attitude control under high bandwidth disturbance but also greatly improves the accuracy of attitude measurement by fully using the dynamic information of novel configuration. Semiphysical simulation results demonstrate the correctness and superiority of the proposed method.

The large-signal theory, including the BEAMLETS model and averaged coupling impedance formalism, of confocal gyrotron traveling-wave amplifiers (gyro-TWAs) with diffractive loss has been derived. As an example, a ${W}$ -band gyro-TWA with uniform confocal circuits and curved-profile magnetic field is theoretically studied and then well validated by three-dimensional particle-in-cell (3-D-PIC) simulation in detail. The results predicted by our code achieve excellent agreement with the PIC simulation over 92–104 GHz regarding the electron efficiency and radio frequency (RF) wave efficiency profile along the circuit position and saturation amplification performance, with a saturation input power difference of less than 20%.

Design and measurement of a distributed radiation coupling (DRC) circuit for the Ku -band TE11-mode gyrotron traveling wave tube (gyro-TWT) amplifier are presented. Different from the dielectric-loaded (DL) waveguide, the proposed DRC circuit can suppress the parasitic modes by achieving sufficient radiation coupling losses. It has the merit of lowering the microwave power loss density, which can improve the tube stability and average power-handling capability. Based on this proposed DRC circuit, a Ku -band TE11-mode gyro-TWT was designed and the particle-in-cell (PIC) simulation shows it can obtain a saturated output power of over 150 kW from 15.3 to 17.2 GHz for an electron beam with a velocity spread of 4.35%. As a comparison, the maximum average microwave power loss density is only 20% of the DL circuit under the same operating parameters. For verification, a DRC circuit was manufactured and cold tested. The maximum deviation between the measured results and our analysis is within 10%.

In this work, a non-idealities aware software-hardware co-design framework for deep neural network (DNN) implemented on memristive crossbar is presented. The device level non-ideal factors such as device conductance variation, nonuniform quantization levels, device-to-device variation and programming failure probability are included in the model. At array level, the impact of line resistance and sneak path are considered using a new fast and accurate line resistance estimation model. The non-linearity and offset of the peripheral circuits are also considered. By incorporating these factors into a unified DNN training process, the neural network performance can be evaluated holistically. Furthermore, the proposed training process can effectively mitigate the impact of these non-idealities and reduce the inference accuracy degradations. Implemented in a hybrid fashion of Python and PyTorch, the proposed framework is evaluated with a simplified 5-layer VGG network implemented on measured $128\times 128$ RRAM array with 3-level weight resolution. For CIFAR-10 tasks, 83% inference accuracy is achieved with less than 3% accuracy drop compared to the ideal model.

Chinese civil servants work in institutional and cultural contexts that are very different from those of their Western counterparts. Very little research has been done to study their job satisfaction. This paper attempts to fill the gap by analyzing data from a survey of 800 civil servants in Beijing. Fifteen independent variables are clustered into three categories: job characteristics, organizational-environmental factors, and personal characteristics. Ordinary least squares regression is used to analyze the relationship between job satisfaction and independent variables. Results show that all six job characteristics such as task variety and salary exert statistically significant influences over the dependent variable; two organizational-environmental factors, work environment safety and relations with coworkers, are also statistically significant in the model. Personal characteristics such as gender exert nominal effects. Implications for practice and further research are also discussed based on the results of regression analysis. Keywords job satisfaction, civil servants, China, job characteristics, For decades, job satisfaction has been an important and intriguing topic for scholars and practitioners of management and psychology. As a social science construct, it is 'one of the most [...]

Periodical radiation spectrum with a frequency difference of ~160 MHz is observed in hot-test experiments of Ku-band gyrotron traveling-wave tubes (gyro-TWTs). By the means of eigenmode analyses and particle-in-cell (PIC) simulation considering the whole output transition section from the interaction circuit end to the output window, we found that the circuit oscillation is pronounced because of frequency self-modulation (FSM). As a comparison, the cutoff taper contributing to the FSM is removed and a new amplifier has been developed; hot-test results indicate that the periodical property has been greatly alleviated as expected and the stability of the amplifier is well improved.

High-performance electrical nanofiber membranes with outstanding electromagnetic interference (EMI) shielding, wearable sensing, self-heating, and hydrophobic performances are highly desirable for modern integrated smart wearable electronic devices. Here, lightweight, flexible, and multifunctional Ti3C2Tx/AgNPs/thermoplastic polyurethane (TPU) nanofiber membranes are prepared through microwave-assisted reduced Ag precursors followed by drip coating of Ti3C2Tx. The introduction of polydimethylsiloxane (PDMS) can endow the nanofiber membrane with hydrophobicity. The PDMS-Ti3C2Tx/AgNPs/TPU nanofiber membrane exhibits excellent EMI shielding effectiveness (SE) of 72.7 dB and outstanding long-term stability when undergoing external forces. The strain sensor based on the PDMS-Ti3C2Tx/AgNPs/TPU nanofiber membrane shows a broad sensing range of 0%–120% with a gauge factor of 146. The pressure sensor based on the PDMS-Ti3C2Tx/AgNPs/TPU nanofiber membrane possesses a wide sensing range of 400–5000 Pa with a gauge factor of 0.35 kPa–1. In addition, the PDMS-Ti3C2Tx/AgNPs/TPU nanofiber membrane presents photothermal conversion (up to 46.6 °C at light intensity of 100 mW/cm2) and hydrophobicity with a water contact angle of 116°. The effective electromagnetic shielding, sensing capability, photothermal conversion, and hydrophobicity of PDMS-Ti3C2Tx/AgNPs/TPU nanofiber membranes enable its fascinating multifunctional applications in wearable devices and ensure its use in harsh environments.

To evaluate the role of the charge transfer (CT) state in the singlet fission (SF) process, we prepared three 3,6-bis(thiophen-2-yl)diketopyrrolopyrrole (TDPP) derivatives with zero (Ph2TDPP), one (Ph2TDPP-COOH), and two (Ph2TDPP-(COOH)2) carboxylic groups, respectively. Their colloidal nanoparticles were also prepared by a simple precipitation method. The SF dynamics and mechanism in these colloid nanoparticles were investigated by using steady-state/transient absorption and fluorescence spectroscopy. Steady-state absorption spectra reveal that the strength of the CT resonance interactions between the adjacent DPP units is increased gradually from Ph2TDPP to Ph2TDPP-COOH and then to Ph2TDPP-(COOH)2. Fluorescence and transient absorption spectra demonstrate that SF is proceeded via a CT-assisted superexchange mechanism in these three nanoparticles. Furthermore, SF rate and yield are enhanced gradually with the increase of the number of the carboxylic group, which may be attributed to the enhancement of the CT coupling strength. The result of this work not only provides a better understanding of the SF mechanism especially for the role of the CT state but also gives some new insights for the design of efficient SF materials based on DPP derivatives.

Pregnant women are often faced with electromagnetic pollution, edema, joint pain, mobility difficulties, and abnormalities in the heart rate. Designing targeted multifunctional intelligent wearable devices to shield against electromagnetic radiation hazards, relieve edema and joint pain, monitor movement and pulse is urgent. Herein, an unprecedented strategy is proposed to combine a metal–organic framework and a fabric substrate for electromagnetic interference shielding. Co@C@carbon fabric (Co-CCF) derived from ZIF-67@cotton fabric was prepared by simple in situ growth and annealing. Subsequently, the Co-PCCF was prepared by encapsulating Co-CCF using polydimethylsiloxane, which improves corrosion resistance and adhesive strength. Co-PCCF-1000 (annealing at 1000 °C) with a double conductive network structure shows efficient electromagnetic shielding performance (blocks more than 99.9% of electromagnetic waves). Co-PCCF with flexibility also shows fantastic fastness and stability to avoid damages during their use by pregnant women (still blocks more than 99% of electromagnetic waves after being repeatedly bent for 500 cycles at 90° and undergoing the ultrasonic treatment for 1 h and 1 M acid/salt/alkali corrosion for 12 h, respectively). In addition, Co-PCCF can reach the required thermal therapy temperature by controlling the voltage (1.5–3 V corresponding to 41.8–84.9 °C) and illumination intensity (0.2 W/cm2corresponding to 70.8 °C). Meanwhile, Co-PCCF can monitor a wide range of human movement in real time, such as pulse, breath, and joint activities. Multifunctional Co-PCCF designed for pregnant women can effectively prevent electromagnetic pollution, relieve joint pain, and detect the human movement and possesses wide application prospects.

Twenty-three new coumarin-furoxan hybrids were synthesized, which exhibited nanomole antiproliferation activities in A2780, A2780/CDDP, MCF-7/ADR, and MDA-MB-231. Among them, compound 9showed the strongest collateral sensitivity to MCF-7/ADR with 499-fold potency compared with MCF-7. Notably, the solubility of compound 9increased 70-fold compared with the lead 2. And preliminary pharmacological studies displayed that compound 9obviously increased Rh123 accumulation in MCF-7/ADR and released NO to produce ROS in lysosomes, which were able to damage lysosomal membrane and induce apoptosis. These results reasonably explained that the collateral sensitivity of compound 9to MCF-7/ADR was closely related to P-gp-mediated lysosome damage and apoptosis. Additionally, compound 9showed a very weak cytotoxicity both in MCF-10A and hERG potassium channels and had a desirable safety in ion cyclotron resonance (ICR) mice. Hence, compound 9was merited to further study for developing a desirable candidate against MDR MCF-7/ADR via a potential mechanism of collateral sensitivity in MDR cancer cell lines.

As a promising micro/nanofabrication method, electrical-assisted nanomachining has obtained substantial attention due to its high material removal rate and attainable superior surface quality. In this study, a rectangular wave electrical signal was applied for nanomachining by a customized tungsten tip. Owing to the coupling effect between the electric field and mechanical force, the cutting depth of the machined grooves can be expanded. In electrical-assisted groove processing, a depth of 270 nm and an aspect ratio of 0.6 on the copper sample can be achieved. The influence of operation parameters including applied voltage, frequency, duty ratio, normal force and cutting speed on the machining performance was investigated in terms of the groove depth, width, aspect ratio, and surface roughness. The potential machining mechanisms should be a combination of electric field force, nanoscale electric discharge, electric contact thermal effects, possible annealing behavior, and scraping and plowing actions induced by mechanical forces.

The Public Goods Game (PGG) encounters hurdles when donations are scarce, resulting in failed game initiations. To investigate such phenomena, we propose a threshold-based spatial PGG model operating on a lattice with periodic boundaries. Players strategically choose between cooperation (C) and defection (D), with PGG initiation determined by a cooperative contribution threshold. Additionally, we introduce an adjustment factor for player reputation, reflecting how individual strategy choices and responses from interacting partners influence reputation changes. We hypothesize that within non-initiated PGG, defectors' reputations decrease, while within initiated PGG, defectors are evaluated and penalized by cooperators. Our findings reveal that higher initiation thresholds can enhance final cooperation levels. Moreover, the inclusion of the reputation adjustment factor acts as a catalyst for cooperative behavior. Interestingly, greater uncertainty in strategy adoption is associated with increased cooperative levels under higher initiation thresholds. This study adds new insights into the evolution of cooperation in the context of spatial structure. [ABSTRACT FROM AUTHOR]

Oculomotor Movement Sensing In article 2303581, Jae‐Hyun Ryou and co‐workers developed an eye movement sensor system made of arrayed piezoelectric transducers that are easily wearable and safe to human body. The sensor can be used in brain‐eye relationship studies to evaluate the brain's functional integrity and cognitive processes by continuous monitoring of oculomotor movements.

With the development of nanotechnology and materials science, bioinspired nanochannels appeared by mimicking the intelligent functions of biological ion channels. They have attracted a great deal of attention in recent years due to their controllable structure and tunable chemical properties. Inspired by the layered microstructure of nacre, 2D layered materials as excellent matrix material of nanochannel come into our field of vision. Bionic nanochannels based on 2D materials have the advantages of facile preparation, tunable channel size and length, easy expansion, and modification, etc. Therefore, the 2D layered nanofluid system based on bionic nanochannels from 2D layered materials has great potential in biomimetic microsensors, membrane separations, energy conversion, and so on. In this paper, we focus on the construction and application of bionic nanochannels based on 2D layer materials. First, a basic understanding of nanochannels based on 2D materials is briefly introduced, we also present the property of the 2D materials and construction strategies of bionic nanochannels. Subsequently, the application of these nanochannels in responsive channels and energy conversion is discussed. The unsolved challenges and prospects of 2D materials-based nanochannels are proposed in the end.

Proximity labelingcatalyzed by promiscuous enzymes, such as APEX2, has emerged as a powerful approach to characterize multiprotein complexes and protein–protein interactions. However, current methods depend on the expression of exogenous fusion proteins and cannot be applied to identify proteins surrounding post-translationallymodified proteins. To address this limitation, we developed a new method to label proximal proteins of interest by antibody-mediated protein A-ascorbate peroxidase 2 (pA-APEX2) labeling (AMAPEX). In this method, a modified protein is bound in situby a specific antibody, which then tethers a pA-APEX2 fusion protein. Activation of APEX2 labels the nearby proteins with biotin; the biotinylated proteins are then purified using streptavidin beads and identified by mass spectrometry. We demonstrated the utility of this approach by profiling the proximal proteins of histone modifications including H3K27me3, H3K9me3, H3K4me3, H4K5ac, and H4K12ac, as well as verifying the co-localization of these identified proteins with bait proteins by published ChIP-seq analysis and nucleosome immunoprecipitation. Overall, AMAPEX is an efficient method to identify proteins that are proximal to modified histones.

This paper presents a convolutional neural network with an attention mechanism for analysing the spectrogram in an x-vector based speaker recognition system. First, the convolutional neural network (CNN) is used to extract the features of the spectrogram. Then, an attention mechanism is designed to calculate the frame weight in the statistical pooling layer. Finally, probability linear discriminant analysis (PLDA) is used as a back end classifier. The system is implemented using Kaldi speech recognition tools and tests on the Voxceleb1 database. The experimental results show that the combination of spectrogram and CNN gains a relative improvement of 6.7% in equal error rate (EER) compared with the x-vector baseline system. The attention mechanism for the statistical layer further leads to a relative improvement of 26.1%. Overall the proposed method outperforms state-of-the-art methods on the Voxceleb1 database.

Purpose: To compare joint work in the lower limb joints during different sub-phases of the gait cycle between Cerebral Palsy (CP) and healthy children. Methods: Eighteen CP and 20 healthy children’s gait data were collected. The CP group included orthoses, intra-muscular injection of botulinum toxin and surgery groups. A motion capture system was used to collect gait data. Joint work was calculated as positive and negative components in six subphases during gait and normalised by speed when comparing the groups. Results: The CP group had a slower walking speed, smaller stride length and longer stance phase than the healthy group. Hip max positive work was 0.12 ± 0.02 Jkg−1/ms−1for the CP group in pre-mid-stance but 0.07 ± 0.01 Jkg−1/ms−1for the healthy group during the terminal phase. In terminal stance, ankle positive work was significantly lower in the CP group (0.12 ± 0.01) than in the healthy group (0.18 ± 0.01). The knee showed a similar distribution of positive work in the stance phase for the two groups. In the ankle and hip, the CP group had energy generation mainly in midstance while the healthy group was mainly in terminal stance. In the ankle, the CP group had larger energy absorption in mid-stance than the healthy children group, while the CP group showed lower energy generation in the terminal stance phase than seen in the healthy group. Conclusion: The qualitative and quantitative analysis of joint work provides useful information for clinicians in the treatment and rehabilitation of CP patients.

Giant surfactants with different numbers of aryl-trifluorovinyl ether-functionalized polyhedral oligomeric silsesquioxane (FVPOSS) heads and one poly(ethylene oxide) (PEO) tail, (FVPOSS)n–PEO227, are precisely synthesized. The phase behaviors of (FVPOSS)n–PEO227at the air–water interface were investigated through surface pressure measurements (isotherm and hysteresis experiments) and the Brewster angle microscopy. Upon increasing the number of FVPOSS heads, the interfacial behaviors of these giant surfactants greatly change. More phase transitions occur during the compression as the number of FVPOSS heads increased from one to two and three. The evolution of morphologies of Langmuir films and compression–expansion hysteresis curves further illustrate phase transitions at the air–water interface. Furthermore, molecular mechanisms to describe phase transitions of (FVPOSS)n–PEO227at the interface are put forward. This study deepens the understanding of interfacial phase behaviors of special giant surfactants and provides knowledge of nanostructure design and construction at the interface.

PANX1, one of the members of the pannexin family, is a highly glycosylated channel-forming protein. Recently, we identified heterozygous variants in PANX1that follow an autosomal dominant inheritance pattern and cause female infertility characterized by oocyte death. In this study, we screened for novel PANX1variants in patients with the phenotype of oocyte death and discovered a new type of inheritance pattern accompanying PANX1variants. We identified two novel homozygous missense variants in PANX1[NM_015368.4 c.712T>C (p.(Ser238Pro) and c.899G>A (p.(Arg300Gln))] associated with the oocyte death phenotype in two families. Both of the homozygous variants altered the PANX1 glycosylation pattern in cultured cells, led to aberrant PANX1 channel activation, and resulted in mouse oocyte death after fertilization in vitro. It is worth noting that the destructive effect of the two homozygous variants on PANX1 function was weaker than that caused by the recently reported heterozygous variants. Our findings enrich the variational spectrum of PANX1and expand the inheritance pattern of PANX1variants to an autosomal recessive mode. This highlights the critical role of PANX1in human oocyte development and helps us to better understand the genetic basis of female infertility due to oocyte death.

As an effective anionic surfactant for chemical flooding, petroleum sulfonate (PS) is often used in conjunction with alkalis to reduce the adsorption loss of PS onto rock and clay surfaces. However, alkali injection can lead to scaling, aggravate the water-sensitive effect of clays, and accelerate polymer hydrolysis. Here, a temperature-responsive biohydrogel-based carrier (XLK) was designed to protect PS from adsorption onto geological features. XLK, an aqueous mixture containing 0.5% xanthan gum, 0.5% locust bean gum, and 2% KCl, was a gel at room temperature and transformed gradually into a sol above 50 °C (sol/gel transition temperature, Tsol/gel). Below the Tsol/gel, most PS was retained in the gel, preventing the adsorption of PS onto quartz sand. Above the Tsol/gel, PS was released into the surrounding medium. After it had been loaded with PS, the storage modulus (G′, Pa) of XLK increased from 102to 103and the loss modulus (G″, Pa) increased from 101to 102. Environmental scanning electron microscopy micrographs showed that PS filled gaps within the cross-linked network structure of XLK. Compared with the aqueous XLK formulation, the addition of hydrolyzed polyacrylamide (HPAM) decreased the melt rate of XLK and the interfacial tension (IFT) of PS. Among the constituents of XLK loaded with PS, KCl had the most obvious effect of lowering the shear modulus of HPAM. Sufficient amounts of KCl were effective in reducing the IFT of PS to ultralow levels (10–3mN/m).

Abstract: Two azobenzene compounds, Disperse Red 1 (DR1) and 4-aminoazobenzene (Aazo), were separately linked to poly(acrylic acid) (PAA) side chains to form PAA-DR1 and PAA-Aazo, which were then associated with poly(ethylene oxide) (PEO) to produce hydrogen-bonded polymer complex fibers. After UV irradiation, the initial modulus and yielding strength of PAA-Aazo/PEO fiber were both increased tremendously, while the mechanical properties of PAA-DR1/PEO fiber only slightly changed. After drawn and dried in vacuum, PAA-DR1/PEO and PAA-Aazo/PEO fibers with an extended length exhibited a contraction of 20% and 25% under UV irradiation, showing potential for photo-actuation. Graphic Abstract:

Numerical simulations are conducted to present the aerothermal performance of a turbine blade tip with cutback squealer rim. Two different tip clearance heights (0.5%, 1.0% of the blade span) and three different cavity depths (2.0%, 3.0%, and 6.0% of the blade span) are investigated. The results show that a high heat transfer coefficient (HTC) strip on the cavity floor appears near the suction side. It extends with the increase of tip clearance height and moves towards the suction side with the increase of cavity depth. The cutback region near the trailing edge has a high HTC value due to the flush of over-tip leakage flow. High HTC region shrinks to the trailing edge with the increase of cavity depth since there is more accumulated flow in the cavity for larger cavity depth. For small tip clearance cases, high HTC distribution appears on the pressure side rim. However, high HTC distribution is observed on suction side rim for large tip clearance height. This is mainly caused by the flow separation and reattachment on the squealer rims.

The emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants BA.2.86 and JN.1 raise concerns regarding their potential to evade immune surveillance and spread globally. Here, we test sera from rhesus macaques immunized with 3 doses of wild-type SARS-CoV-2 receptor-binding domain (RBD)-Fc adjuvanted with the STING agonist CF501. We find that the sera can potently neutralize pseudotyped XBB.1.5, XBB.1.16, CH.1.1, EG.5, BA.2.86, and JN.1, with 50% neutralization titers ranging from 3,494 to 7,424. We also demonstrate that CF501, but not Alum, can enhance immunogenicity of the RBD from wild-type SARS-CoV-2 to improve induction of broadly neutralizing antibodies (bnAbs) with binding specificity and activity similar to those of SA55, BN03, and S309, thus exhibiting extraordinary broad-spectrum neutralizing activity. Overall, the RBD from wild-type SARS-CoV-2 also contains conservative epitopes. The RBD-Fc adjuvanted by CF501 can elicit potent bnAbs against JN.1, BA.2.86, and other XBB subvariants. This strategy can be adopted to develop broad-spectrum vaccines to combat future emerging and reemerging viral infectious diseases.