Electrochemical CO_(2)reduction to formate is a potential approach to achieving global carbon neutrality.Here,Cu1Bi1bimetallic catalyst was prepared by a co-precipitation method.It has a ginger like composite structur...Electrochemical CO_(2)reduction to formate is a potential approach to achieving global carbon neutrality.Here,Cu1Bi1bimetallic catalyst was prepared by a co-precipitation method.It has a ginger like composite structure(CuO/CuBi_(2)O_(4))and exhibited a high formate faradaic efficiency of 98.07%at–0.98 V and a large current density of–56.12 mA.cm^(-2)at–1.28 V,which is twice as high as Bi2O3catalyst.Especially,high selectivity(FE^(–)_(HCOO)>85%)is maintained over a wide potential window of 500 mV.In-situ Raman measurements and structure characterization revealed that the reduced Cu1Bi1bimetallic catalyst possesses abundant Cu-Bi interfaces and residual Bi-O structures.The abundant Cu-Bi interface structures on the catalyst surface can provide abundant active sites for CO_(2)RR,while the Bi-O structures may stabilize the CO_(2)^(*–)intermediate.The synergistic effect of abundant Cu-Bi interfaces and Bi-O species promotes the efficient synthesis of formate by following the OCHO^(*)pathway.展开更多
This study aims to address the deviation in downstream tasks caused by inaccurate recognition results when applying Automatic Speech Recognition(ASR)technology in the Air Traffic Control(ATC)field.This paper presents ...This study aims to address the deviation in downstream tasks caused by inaccurate recognition results when applying Automatic Speech Recognition(ASR)technology in the Air Traffic Control(ATC)field.This paper presents a novel cascaded model architecture,namely Conformer-CTC/Attention-T5(CCAT),to build a highly accurate and robust ATC speech recognition model.To tackle the challenges posed by noise and fast speech rate in ATC,the Conformer model is employed to extract robust and discriminative speech representations from raw waveforms.On the decoding side,the Attention mechanism is integrated to facilitate precise alignment between input features and output characters.The Text-To-Text Transfer Transformer(T5)language model is also introduced to handle particular pronunciations and code-mixing issues,providing more accurate and concise textual output for downstream tasks.To enhance the model’s robustness,transfer learning and data augmentation techniques are utilized in the training strategy.The model’s performance is optimized by performing hyperparameter tunings,such as adjusting the number of attention heads,encoder layers,and the weights of the loss function.The experimental results demonstrate the significant contributions of data augmentation,hyperparameter tuning,and error correction models to the overall model performance.On the Our ATC Corpus dataset,the proposed model achieves a Character Error Rate(CER)of 3.44%,representing a 3.64%improvement compared to the baseline model.Moreover,the effectiveness of the proposed model is validated on two publicly available datasets.On the AISHELL-1 dataset,the CCAT model achieves a CER of 3.42%,showcasing a 1.23%improvement over the baseline model.Similarly,on the LibriSpeech dataset,the CCAT model achieves a Word Error Rate(WER)of 5.27%,demonstrating a performance improvement of 7.67%compared to the baseline model.Additionally,this paper proposes an evaluation criterion for assessing the robustness of ATC speech recognition systems.In robustness evaluation experiments based on this criterion,the proposed model demonstrates a performance improvement of 22%compared to the baseline model.展开更多
Ti3C2Tx,a novel two-dimensional layer material,is widely used as electrode materials of supercapacitor due to its good metal conductivity,redox reaction active surface,and so on.However,there are many challenges to be...Ti3C2Tx,a novel two-dimensional layer material,is widely used as electrode materials of supercapacitor due to its good metal conductivity,redox reaction active surface,and so on.However,there are many challenges to be addressed which impede Ti3C2Tx obtaining the ideal specific capacitance,such as restacking,re-crushing,and oxidation of titanium.Recently,many advances have been proposed to enhance capacitance performance of Ti3C2Tx.In this review,recent strategies for improving specific capacitance are summarized and compared,for example,film formation,surface modification,and composite method.Furthermore,in order to comprehend the mechanism of those efforts,this review analyzes the energy storage performance in different electrolytes and influencing factors.This review is expected to predict redouble research direction of Ti3C2Tx materials in supercapacitors.展开更多
In this paper, a video fire detection method is proposed, which demonstrated good performance in indoor environment. Three main novel ideas have been introduced. Firstly, a flame color model in RGB and HIS color space...In this paper, a video fire detection method is proposed, which demonstrated good performance in indoor environment. Three main novel ideas have been introduced. Firstly, a flame color model in RGB and HIS color space is used to extract pre-detected regions instead of traditional motion differential method, as it’s more suitable for fire detection in indoor environment. Secondly, according to the flicker characteristic of the flame, similarity and two main values of centroid motion are proposed. At the same time, a simple but effective method for tracking the same regions in consecutive frames is established. Thirdly,a multi-expert system consisting of color component dispersion,similarity and centroid motion is established to identify flames.The proposed method has been tested on a very large dataset of fire videos acquired both in real indoor environment tests and from the Internet. The experimental results show that the proposed approach achieved a balance between the false positive rate and the false negative rate, and demonstrated a better performance in terms of overall accuracy and F standard with respect to other similar fire detection methods in indoor environment.展开更多
The different conditions of use of a component result in a variety of damage levels.Therefore,excluding differences in shape and size,used parts show a high degree of uncertainty regarding failure characteristics,qual...The different conditions of use of a component result in a variety of damage levels.Therefore,excluding differences in shape and size,used parts show a high degree of uncertainty regarding failure characteristics,quality conditions,and remaining life,which seriously affects the efficiency of a remanufacturing scheme design.Aiming to address this problem,a remanufacturing scheme design method based on the reconstruction of incomplete information of used parts is proposed.First,the remaining life of the reconstructed model is predicted by finite element analysis,and the demand for the next life cycle is determined.Second,the scanned 3D damage point cloud data are registered with the original point cloud data using the integral iterative method to construct a missing point cloud model to achieve the restoration of geometric information.Then,according to reverse engineering and laser cladding remanufacturing,the tool remanufacturing process path can be generated by the tool contact point path section line method.Finally,the proposed method is adopted for turbine blades to evaluate the effectiveness and feasibility of the proposed scheme.This study proposes a remanufacturing scheme design method based on the incomplete reconstruction of used part information to solve the uncertain and highly personalized problems in remanufacturing.展开更多
BACKGROUND Vestigial like family member 3(VGLL3)is associated with the prognosis of epithelial ovarian cancer and soft tissue sarcoma,but its role in gastric cancer(GC)is unclear.AIM To explore the expression pattern ...BACKGROUND Vestigial like family member 3(VGLL3)is associated with the prognosis of epithelial ovarian cancer and soft tissue sarcoma,but its role in gastric cancer(GC)is unclear.AIM To explore the expression pattern and clinical significance of VGLL3 in GC.METHODS Integrative analysis was performed on the GC transcriptome profiles and survival information deposited in the ONCOMINE,GEPIA,and ONCOLNC databases.The expression levels of VGLL3 mRNA and protein were analyzed in the freshly resected tumor and normal gastric tissues from GC patients by quantitative RT-PCR and Western blot,respectively.In addition,the in situ expression of VGLL3 in the GC tissues was determined by immunohistochemistry(IHC),and the patients were accordingly classified into the high and low expression groups.The correlation of VGLL3 expression status with patient prognosis was then determined by univariate and multivariate Cox regression analyses.RESULTS Analysis of the ONCOMINE and GEPIA databases showed that VGLL3 was significantly up-regulated in GC tissues(P=0.003),and associated with the tumor TNM stage(P=0.0163).The high VGLL3 expression group had a significantly worse prognosis compared to the low expression group,as per both GEPIA(P=0.0057)and ONCOLNC(P=0.01).The bioinformatics results were validated by the significantly higher VGLL3 mRNA and protein levels in the GC tissues compared to the adjacent normal tissues(P<0.001)in a cohort of 30 GC patients.Furthermore,high in situ expression of VGLL3 protein was associated with more advanced N and TNM stages and HER2 mutation(P<0.05)in a cohort of 172 patients.Kaplan-Meier analysis showed that the high VGLL3 expression group had a worse prognosis compared to the low expression group(P=0.019).Multivariate analysis showed that VGLL3 expression status was an independent risk factor for prognosis.In addition,the prognostic risk model nomogram showed that VGLL3 was the most important indicator,with an area under the receiver operating characteristic(ROC)curve(AUC)of 0.613 for 3-year survival and 0.706 for 5-year survival.Finally,the protein interaction network analysis revealed that VGLL3 is likely involved in the Hippo signaling pathway.CONCLUSION VGLL3 is overexpressed in GC tissues and associated with a poor prognosis,indicating its potential as a novel prognosis biomarker and therapeutic target for GC.展开更多
Metasurface provides subwavelength structures for manipulating wavefronts of light. The benefits of subwavelength components offer a continuous modulation of amplitude, phase, and polarization, thus eliminating the pr...Metasurface provides subwavelength structures for manipulating wavefronts of light. The benefits of subwavelength components offer a continuous modulation of amplitude, phase, and polarization, thus eliminating the production of higher-order images and improving the utilization of light intensity. Despite the rapid progress in this field, multiparameter control of light using single layer metasurface is rarely reported. In fact, multiparameter control of light helps to improve information storage capacity and image fidelity. With simultaneous manipulation of polarization and amplitude at each pixel, it is possible to encode two separate images into one metasurface and reconstruct them under proper conditions. In a proof of concept experiment, we demonstrate an independent display of two binary images at the same position with polarization de-multiplexing from a single metasurface. This unique technology of encoding two images through amplitude and polarization manipulation provides a new opportunity for various applications in, such as encryption, information storage, polarization holograms, optical communications and fundamental physics.展开更多
The focus of this paper is on the measurement and calculation model of void fraction for the vertical upward co-current air-water slug flow in a circular tube of 15 mm inner diameter. High-speed photography and optica...The focus of this paper is on the measurement and calculation model of void fraction for the vertical upward co-current air-water slug flow in a circular tube of 15 mm inner diameter. High-speed photography and optical probes were utilized, with water superficial velocity ranging from 0.089 to 0.65 m·s^(-1)and gas superficial velocity ranging from 0.049 to 0.65 m·s^(-1). A new void fraction model based on the local parameters was proposed, disposing the slug flow as a combination of Taylor bubbles and liquid slugs. In the Taylor bubble region, correction factors of liquid film thickness Cδand nose shape CZ*were proposed to calculate aTB. In the liquid slug region, the radial void fraction distribution profiles were obtained to calculate aLS, by employing the image processing technique based on supervised machine learning. Results showed that the void fraction proportion in Taylor bubbles occupied crucial contribution to the overall void fraction. Multiple types of void fraction predictive correlations were assessed using the present data. The performance of the Schmidt model was optimal, while some models for slug flow performed not outstanding. Additionally, a predictive correlation was correlated between the central local void fraction and the cross-sectional averaged void fraction, as a straightforward form of the void fraction calculation model. The predictive correlation showed a good agreement with the present experimental data, as well as the data of Olerni et al., indicating that the new model was effective and applicable under the slug flow conditions.展开更多
Objective To investigate the alterations of cardiac electrophysiological properties and substantial mechanism and find the stable arrhythmia mouse model in Kunming(KM) and C57BL6/J(C57) mice.Methods Electrocardiogram ...Objective To investigate the alterations of cardiac electrophysiological properties and substantial mechanism and find the stable arrhythmia mouse model in Kunming(KM) and C57BL6/J(C57) mice.Methods Electrocardiogram recordings were used to analyze the QT interval in vivo,and monophasic action potential of right and left ventricular epicardium was recorded to elicit changes of action potential duration(APD) in conventional and programmed electrical stimulation(PES).Transient outward potassium current(I to) was recorded via whole-cell patch-clamp technique in single right and left epicardial myocytes.Results QT interval was prolonged in KM mice relative to C57 mice(62.51±4.47 ms vs.52.59±4.85 ms,P<0.05).The APD at 50% repolarization of the left ventricular epicardium(18.60±0.91 ms vs.12.90±0.35 ms),and APDs at 50%(17.31±6.05 ms vs.12.00±3.24 ms) and 70% repolarization(36.13±5.32 ms vs.21.95±8.06 ms) of the right ventricular epicardium in KM mice were significantly prolonged compared with C57 mice,respectively(all P<0.05).KM mice were more sensitive to PES-induced ventricular tachycardia(25%,3 of 12 hearts),and especially to Burst-induced ventricular tachycardia(50%,6 of 12 hearts) compared with C57 mice,which were 20%(2 of 10 hearts) and 30%(3 of 10 hearts) respectively.I to densities both in the left and right ventricular epicardial myocytes from KM mice were significantly decreased compared with C57 mice,respectively(all P<0.01).Conclusion Our data showed that KM mice with the prolonged QT interval and APD are vulnerabilities to ventricular arrhythmia,which are attributed to lower I to densities in ventricular myocytes obtained from KM mice than that from C57 mice.展开更多
BACKGROUND Nodular fasciitis(NF)is a benign disease originating from fascial tissue and most commonly occurs in the extremities,followed by the trunk,head,and neck.NF of the head and neck occurs mainly in the face and...BACKGROUND Nodular fasciitis(NF)is a benign disease originating from fascial tissue and most commonly occurs in the extremities,followed by the trunk,head,and neck.NF of the head and neck occurs mainly in the face and neck,and it has not been reported in the occipital region.CASE SUMMARY A 30-year-old man was admitted because of a mass in the left occipital region.Imaging examination revealed a soft tissue nodule in the left occipital area.An enhanced magnetic resonance imaging scan showed characteristic inverted target and fascial tail signs.Histopathological analysis showed a large amount of spindle cell proliferation,and immunohistochemistry showed positive expression of SMA in the spindle cells in the lesion.Finally,nodular fasciitis was diagnosed.CONCLUSION NF of the head and neck is rare,but the possibility of NF should be considered when nodules or masses with rapid subcutaneous growth are found and tenderness in the head and neck is present.Imaging examination,in combination with clinical manifestations and histopathological examination,can improve the diagnostic accuracy for the disease.After diagnosis,local surgical resection is the first choice of treatment.展开更多
We report an in-depth investigation on the out-of-plane lower critical field Hc1 of the KCa2(Fe1-xCox)4As4F2(12442-type,x=0,0.1).The multi-gap feature is revealed by the kink in the temperature-dependent Hc1(T)curve f...We report an in-depth investigation on the out-of-plane lower critical field Hc1 of the KCa2(Fe1-xCox)4As4F2(12442-type,x=0,0.1).The multi-gap feature is revealed by the kink in the temperature-dependent Hc1(T)curve for the two samples with different doping levels.Based on a simplified two-gap model,the magnitudes of the two gaps are determined to beΔ1=1.2 meV andΔ2=5.0 meV for the sample with x=0,Δ1=0.86 meV andΔ2=2.8 meV for that with x=0.1.With the cobalt doping,the ratio of energy gap to critical transition temperature(Δ/kBTc)remains almost unchanged for the smaller gap and is suppressed by 20%for the larger gap.For the undoped KCa2Fe4As4F2,the obtained gap sizes are generally consistent with the results of angle-resolved photoemission spectroscopy experiments.展开更多
The thermoelectric materials have been considered as a potential candidate for the new power generation technology based on their reversible heat and electricity conversion.Lead telluride(Pb Te) is regarded as an exce...The thermoelectric materials have been considered as a potential candidate for the new power generation technology based on their reversible heat and electricity conversion.Lead telluride(Pb Te) is regarded as an excellent mid-temperature thermoelectric material due to its suitable intrinsic thermoelectric properties.So tremendous efforts have been done to improve the thermoelectric performance of Pb Te,and figures of merit,z_T > 2.0,have been reported.Main strategies for optimizing the thermoelectric performance have been focused as the main line of this review.The band engineering and phonon scattering engineering as two main effective strategies are systemically summarized here.The band engineering,like band convergence,resonant levels,and band flatting have been addressed in improving the power factor.Additionally,phonon scattering engineerings,such as atomic-scale,nano-scale,meso-scale,and multi-scale phonon scatterings have been applied to reduce the thermal conductivity.Besides,some successful synergistic effects based on band engineerings and phonon scatterings are illustrated as a simultaneous way to optimize both the power factor and thermal conductivity.Summarizing the above three main parts,we point out that the synergistic effects should be effectively exploited,and these may further boost the thermoelectric performance of Pb Te alloys and can be extended to other thermoelectric materials.展开更多
A computational study was carried out on bubble dynamic behaviors and bubble size distributions in a pressurized lab-scale gas-solid fluidized bed of Geldart A particles.High-resolution 3-D numerical simulations were ...A computational study was carried out on bubble dynamic behaviors and bubble size distributions in a pressurized lab-scale gas-solid fluidized bed of Geldart A particles.High-resolution 3-D numerical simulations were performed using the two-fluid model based on the kinetic theory of granular flow.A finegrid,which is in the range of 3–4 particle diameters,was utilized in order to capture bubble structures explicitly without breaking down the continuum assumption for the solid phase.A novel bubble tracking scheme was developed in combination with a 3-D detection and tracking algorithm(MS3 DATA)and applied to detect the bubble statistics,such as bubble size,location in each time frame and relative position between two adjacent time frames,from numerical simulations.The spatial coordinates and corresponding void fraction data were sampled at 100 Hz for data analyzing.The bubble coalescence/break-up frequencies and the daughter bubble size distribution were evaluated by using the new bubble tracking algorithm.The results showed that the bubble size distributed non-uniformly over cross-sections in the bed.The equilibrium bubble diameter due to bubble break-up and coalescence dynamics can be obtained,and the bubble rise velocity follows Davidson’s correlation closely.Good agreements were obtained between the computed results and that predicted by using the bubble break-up model proposed in our previous work.The computational bubble tracking method showed the potential of analyzing bubble motions and the coalescence and break-up characteristics based on time series data sets of void fraction maps obtained numerically and experimentally.展开更多
Detection of structural changes from an operational process is a major goal in machine condition monitoring. Existing methods for this purpose are mainly based on retrospective analysis, resulting in a large detection...Detection of structural changes from an operational process is a major goal in machine condition monitoring. Existing methods for this purpose are mainly based on retrospective analysis, resulting in a large detection delay that limits their usages in real applications. This paper presents a new adaptive real-time change detection algorithm, an extension of the recent research by combining with an incremental sliding-window strategy, to handle the multi-change detection in long-term monitoring of machine operations. In particular, in the framework, Hilbert space embedding of distribution is used to map the original data into the Re-producing Kernel Hilbert Space(RKHS) for change detection; then, a new adaptive threshold strategy can be developed when making change decision, in which a global factor(used to control the coarse-to-fine level of detection) is introduced to replace the fixed value of threshold. Through experiments on a range of real testing data which was collected from an experimental rotating machinery system, the excellent detection performances of the algorithm for engineering applications were demonstrated. Compared with state-ofthe-art methods, the proposed algorithm can be more suitable for long-term machinery condition monitoring without any manual re-calibration, thus is promising in modern industries.展开更多
The 2018 M_(W)6.7 Iburi earthquake shocked the eastern Iburi region to the west of the Hidaka Collision Zone in Hokkaido,which is a destructive inland earthquake.We resolved the kinematic rupture process of the event ...The 2018 M_(W)6.7 Iburi earthquake shocked the eastern Iburi region to the west of the Hidaka Collision Zone in Hokkaido,which is a destructive inland earthquake.We resolved the kinematic rupture process of the event by combining strong motions(SM)and synthetic aperture radar(SAR)images in a joint inversion.The results reveal that the duration of the whole rupture is about 17s,yielding a total seismic moment of 1.4×10^(19)N·m(M_(W)=6.7).The main slip area is located at a depth of approximately 24 km with a peak slip of~0.8m above the hypocenter.The comparison with the regional velocity model shows the earthquake was initiated in the upper mantle,while the majority of slips are located in the lower crust,which is an“aseismic”domain in the typical sandwich model.The location of the major slip area is consistent with a high-conductivity volume.We proposed a mechanism of low frictional property(<0.3)produced by high pore pressure to explain the abnormal high dip angle and centroid depth located in the ductile lower-crust.Aftershocks are distributed in areas where the Coulomb frictional stress increases due to co-seismic displacement with a mechanism conjugating to the mainshock.展开更多
To reveal the intrinsic properties of the basic superconducting units,i.e.,the single layered FeSe/FeAs in iron-based superconductors or CuO_(2) planes in cuprate superconductors,is a necessary prerequisite for unders...To reveal the intrinsic properties of the basic superconducting units,i.e.,the single layered FeSe/FeAs in iron-based superconductors or CuO_(2) planes in cuprate superconductors,is a necessary prerequisite for understanding the mechanism of high-Tc superconductivity.Up to now,an isolated FeAs layer has rarely been studied due to the difficulty in materials synthesis.Here,we report a scanning tunneling microscopy/spectroscopy(STM/STS)study on the iron-based superconductor KCa_(2)Fe_(4)As_(4)F_(2).In situ cleavage produced a single FeAs layer covered by a reconstructed K surface,which is isolated from the bulk by the underlying CaF layer and shows multi-band superconductivity with a much lower T_(c) than its bulk counterpart.In the exposed As-terminated regions with coverage of scattered K atoms,a pseudogap was observed,leading to an inhomogeneous superconductivity without long-range phase coherence in real space,which is remarkably similar to the high-T_(c) cuprate superconductors.These results provide a new perspective to understanding the origin of superconductivity in iron-based superconductors.展开更多
基金financially supported by the National Natural Science Foundation of China(22172082,21978137,and 21878162)the Natural Science Foundation of Tianjin(20JCZDJC00770)+1 种基金the NCC Fund(NCC2020FH05)the Fundamental Research Funds for the Central Universities。
文摘Electrochemical CO_(2)reduction to formate is a potential approach to achieving global carbon neutrality.Here,Cu1Bi1bimetallic catalyst was prepared by a co-precipitation method.It has a ginger like composite structure(CuO/CuBi_(2)O_(4))and exhibited a high formate faradaic efficiency of 98.07%at–0.98 V and a large current density of–56.12 mA.cm^(-2)at–1.28 V,which is twice as high as Bi2O3catalyst.Especially,high selectivity(FE^(–)_(HCOO)>85%)is maintained over a wide potential window of 500 mV.In-situ Raman measurements and structure characterization revealed that the reduced Cu1Bi1bimetallic catalyst possesses abundant Cu-Bi interfaces and residual Bi-O structures.The abundant Cu-Bi interface structures on the catalyst surface can provide abundant active sites for CO_(2)RR,while the Bi-O structures may stabilize the CO_(2)^(*–)intermediate.The synergistic effect of abundant Cu-Bi interfaces and Bi-O species promotes the efficient synthesis of formate by following the OCHO^(*)pathway.
基金This study was co-supported by the National Key R&D Program of China(No.2021YFF0603904)National Natural Science Foundation of China(U1733203)Safety Capacity Building Project of Civil Aviation Administration of China(TM2019-16-1/3).
文摘This study aims to address the deviation in downstream tasks caused by inaccurate recognition results when applying Automatic Speech Recognition(ASR)technology in the Air Traffic Control(ATC)field.This paper presents a novel cascaded model architecture,namely Conformer-CTC/Attention-T5(CCAT),to build a highly accurate and robust ATC speech recognition model.To tackle the challenges posed by noise and fast speech rate in ATC,the Conformer model is employed to extract robust and discriminative speech representations from raw waveforms.On the decoding side,the Attention mechanism is integrated to facilitate precise alignment between input features and output characters.The Text-To-Text Transfer Transformer(T5)language model is also introduced to handle particular pronunciations and code-mixing issues,providing more accurate and concise textual output for downstream tasks.To enhance the model’s robustness,transfer learning and data augmentation techniques are utilized in the training strategy.The model’s performance is optimized by performing hyperparameter tunings,such as adjusting the number of attention heads,encoder layers,and the weights of the loss function.The experimental results demonstrate the significant contributions of data augmentation,hyperparameter tuning,and error correction models to the overall model performance.On the Our ATC Corpus dataset,the proposed model achieves a Character Error Rate(CER)of 3.44%,representing a 3.64%improvement compared to the baseline model.Moreover,the effectiveness of the proposed model is validated on two publicly available datasets.On the AISHELL-1 dataset,the CCAT model achieves a CER of 3.42%,showcasing a 1.23%improvement over the baseline model.Similarly,on the LibriSpeech dataset,the CCAT model achieves a Word Error Rate(WER)of 5.27%,demonstrating a performance improvement of 7.67%compared to the baseline model.Additionally,this paper proposes an evaluation criterion for assessing the robustness of ATC speech recognition systems.In robustness evaluation experiments based on this criterion,the proposed model demonstrates a performance improvement of 22%compared to the baseline model.
基金National Natural Science Foundation of China with Grant No.21905304Natural Science Foundation of Shandong Province(No.ZR2019BEM031)the Fundamental Research Funds for the Central Universities(Nos.18CX02158A and 19CX05001A).
文摘Ti3C2Tx,a novel two-dimensional layer material,is widely used as electrode materials of supercapacitor due to its good metal conductivity,redox reaction active surface,and so on.However,there are many challenges to be addressed which impede Ti3C2Tx obtaining the ideal specific capacitance,such as restacking,re-crushing,and oxidation of titanium.Recently,many advances have been proposed to enhance capacitance performance of Ti3C2Tx.In this review,recent strategies for improving specific capacitance are summarized and compared,for example,film formation,surface modification,and composite method.Furthermore,in order to comprehend the mechanism of those efforts,this review analyzes the energy storage performance in different electrolytes and influencing factors.This review is expected to predict redouble research direction of Ti3C2Tx materials in supercapacitors.
基金supported by National Natural Science Foundation of China(41471387,41631072)
文摘In this paper, a video fire detection method is proposed, which demonstrated good performance in indoor environment. Three main novel ideas have been introduced. Firstly, a flame color model in RGB and HIS color space is used to extract pre-detected regions instead of traditional motion differential method, as it’s more suitable for fire detection in indoor environment. Secondly, according to the flicker characteristic of the flame, similarity and two main values of centroid motion are proposed. At the same time, a simple but effective method for tracking the same regions in consecutive frames is established. Thirdly,a multi-expert system consisting of color component dispersion,similarity and centroid motion is established to identify flames.The proposed method has been tested on a very large dataset of fire videos acquired both in real indoor environment tests and from the Internet. The experimental results show that the proposed approach achieved a balance between the false positive rate and the false negative rate, and demonstrated a better performance in terms of overall accuracy and F standard with respect to other similar fire detection methods in indoor environment.
基金Supported by Plateau Disciplines in ShanghaiNational Natural Science Foundation of China (Grant No. 51675388)Hubei Provincial Department of Education of China (Grant No. D20181102)
文摘The different conditions of use of a component result in a variety of damage levels.Therefore,excluding differences in shape and size,used parts show a high degree of uncertainty regarding failure characteristics,quality conditions,and remaining life,which seriously affects the efficiency of a remanufacturing scheme design.Aiming to address this problem,a remanufacturing scheme design method based on the reconstruction of incomplete information of used parts is proposed.First,the remaining life of the reconstructed model is predicted by finite element analysis,and the demand for the next life cycle is determined.Second,the scanned 3D damage point cloud data are registered with the original point cloud data using the integral iterative method to construct a missing point cloud model to achieve the restoration of geometric information.Then,according to reverse engineering and laser cladding remanufacturing,the tool remanufacturing process path can be generated by the tool contact point path section line method.Finally,the proposed method is adopted for turbine blades to evaluate the effectiveness and feasibility of the proposed scheme.This study proposes a remanufacturing scheme design method based on the incomplete reconstruction of used part information to solve the uncertain and highly personalized problems in remanufacturing.
基金Supported by the Natural Science Foundation of Jiangsu Province,No.BK20171150the National Natural Science Foundation of China,No.81502042+1 种基金Research Project of Health and Family Planning Commission of Wuxi,No.Q201758Nanchang Hongda Jianghua Educational Foundation
文摘BACKGROUND Vestigial like family member 3(VGLL3)is associated with the prognosis of epithelial ovarian cancer and soft tissue sarcoma,but its role in gastric cancer(GC)is unclear.AIM To explore the expression pattern and clinical significance of VGLL3 in GC.METHODS Integrative analysis was performed on the GC transcriptome profiles and survival information deposited in the ONCOMINE,GEPIA,and ONCOLNC databases.The expression levels of VGLL3 mRNA and protein were analyzed in the freshly resected tumor and normal gastric tissues from GC patients by quantitative RT-PCR and Western blot,respectively.In addition,the in situ expression of VGLL3 in the GC tissues was determined by immunohistochemistry(IHC),and the patients were accordingly classified into the high and low expression groups.The correlation of VGLL3 expression status with patient prognosis was then determined by univariate and multivariate Cox regression analyses.RESULTS Analysis of the ONCOMINE and GEPIA databases showed that VGLL3 was significantly up-regulated in GC tissues(P=0.003),and associated with the tumor TNM stage(P=0.0163).The high VGLL3 expression group had a significantly worse prognosis compared to the low expression group,as per both GEPIA(P=0.0057)and ONCOLNC(P=0.01).The bioinformatics results were validated by the significantly higher VGLL3 mRNA and protein levels in the GC tissues compared to the adjacent normal tissues(P<0.001)in a cohort of 30 GC patients.Furthermore,high in situ expression of VGLL3 protein was associated with more advanced N and TNM stages and HER2 mutation(P<0.05)in a cohort of 172 patients.Kaplan-Meier analysis showed that the high VGLL3 expression group had a worse prognosis compared to the low expression group(P=0.019).Multivariate analysis showed that VGLL3 expression status was an independent risk factor for prognosis.In addition,the prognostic risk model nomogram showed that VGLL3 was the most important indicator,with an area under the receiver operating characteristic(ROC)curve(AUC)of 0.613 for 3-year survival and 0.706 for 5-year survival.Finally,the protein interaction network analysis revealed that VGLL3 is likely involved in the Hippo signaling pathway.CONCLUSION VGLL3 is overexpressed in GC tissues and associated with a poor prognosis,indicating its potential as a novel prognosis biomarker and therapeutic target for GC.
基金the 973 Program of China (grant No. 2013CBA01702)the National Natural Science Foundation of China (grant Nos. 11474206, 11404224, 1174243, and 11774246)+4 种基金the Beijing Youth Top-Notch Talent Training Plan (CIT&TCD 201504080)the Beijing Nova Program (grant No. Z161100004916100)the Beijing Talents Project (grant No. 2018A19)Capacity Building for Science & Technology Innovation-Fundamental Scientific Research Funds (grand No. 025185305000/142)the Scientific Research Base Development Program of the Beijing Municipal Commission of Education.
文摘Metasurface provides subwavelength structures for manipulating wavefronts of light. The benefits of subwavelength components offer a continuous modulation of amplitude, phase, and polarization, thus eliminating the production of higher-order images and improving the utilization of light intensity. Despite the rapid progress in this field, multiparameter control of light using single layer metasurface is rarely reported. In fact, multiparameter control of light helps to improve information storage capacity and image fidelity. With simultaneous manipulation of polarization and amplitude at each pixel, it is possible to encode two separate images into one metasurface and reconstruct them under proper conditions. In a proof of concept experiment, we demonstrate an independent display of two binary images at the same position with polarization de-multiplexing from a single metasurface. This unique technology of encoding two images through amplitude and polarization manipulation provides a new opportunity for various applications in, such as encryption, information storage, polarization holograms, optical communications and fundamental physics.
基金supported by National Key Research and Development Program of China ( 2018YFE011061)。
文摘The focus of this paper is on the measurement and calculation model of void fraction for the vertical upward co-current air-water slug flow in a circular tube of 15 mm inner diameter. High-speed photography and optical probes were utilized, with water superficial velocity ranging from 0.089 to 0.65 m·s^(-1)and gas superficial velocity ranging from 0.049 to 0.65 m·s^(-1). A new void fraction model based on the local parameters was proposed, disposing the slug flow as a combination of Taylor bubbles and liquid slugs. In the Taylor bubble region, correction factors of liquid film thickness Cδand nose shape CZ*were proposed to calculate aTB. In the liquid slug region, the radial void fraction distribution profiles were obtained to calculate aLS, by employing the image processing technique based on supervised machine learning. Results showed that the void fraction proportion in Taylor bubbles occupied crucial contribution to the overall void fraction. Multiple types of void fraction predictive correlations were assessed using the present data. The performance of the Schmidt model was optimal, while some models for slug flow performed not outstanding. Additionally, a predictive correlation was correlated between the central local void fraction and the cross-sectional averaged void fraction, as a straightforward form of the void fraction calculation model. The predictive correlation showed a good agreement with the present experimental data, as well as the data of Olerni et al., indicating that the new model was effective and applicable under the slug flow conditions.
基金Supported by the National Natural Science Foundation of China(81070142)Natural Science Foundation of Hubei Province (2011CDB504)
文摘Objective To investigate the alterations of cardiac electrophysiological properties and substantial mechanism and find the stable arrhythmia mouse model in Kunming(KM) and C57BL6/J(C57) mice.Methods Electrocardiogram recordings were used to analyze the QT interval in vivo,and monophasic action potential of right and left ventricular epicardium was recorded to elicit changes of action potential duration(APD) in conventional and programmed electrical stimulation(PES).Transient outward potassium current(I to) was recorded via whole-cell patch-clamp technique in single right and left epicardial myocytes.Results QT interval was prolonged in KM mice relative to C57 mice(62.51±4.47 ms vs.52.59±4.85 ms,P<0.05).The APD at 50% repolarization of the left ventricular epicardium(18.60±0.91 ms vs.12.90±0.35 ms),and APDs at 50%(17.31±6.05 ms vs.12.00±3.24 ms) and 70% repolarization(36.13±5.32 ms vs.21.95±8.06 ms) of the right ventricular epicardium in KM mice were significantly prolonged compared with C57 mice,respectively(all P<0.05).KM mice were more sensitive to PES-induced ventricular tachycardia(25%,3 of 12 hearts),and especially to Burst-induced ventricular tachycardia(50%,6 of 12 hearts) compared with C57 mice,which were 20%(2 of 10 hearts) and 30%(3 of 10 hearts) respectively.I to densities both in the left and right ventricular epicardial myocytes from KM mice were significantly decreased compared with C57 mice,respectively(all P<0.01).Conclusion Our data showed that KM mice with the prolonged QT interval and APD are vulnerabilities to ventricular arrhythmia,which are attributed to lower I to densities in ventricular myocytes obtained from KM mice than that from C57 mice.
文摘BACKGROUND Nodular fasciitis(NF)is a benign disease originating from fascial tissue and most commonly occurs in the extremities,followed by the trunk,head,and neck.NF of the head and neck occurs mainly in the face and neck,and it has not been reported in the occipital region.CASE SUMMARY A 30-year-old man was admitted because of a mass in the left occipital region.Imaging examination revealed a soft tissue nodule in the left occipital area.An enhanced magnetic resonance imaging scan showed characteristic inverted target and fascial tail signs.Histopathological analysis showed a large amount of spindle cell proliferation,and immunohistochemistry showed positive expression of SMA in the spindle cells in the lesion.Finally,nodular fasciitis was diagnosed.CONCLUSION NF of the head and neck is rare,but the possibility of NF should be considered when nodules or masses with rapid subcutaneous growth are found and tenderness in the head and neck is present.Imaging examination,in combination with clinical manifestations and histopathological examination,can improve the diagnostic accuracy for the disease.After diagnosis,local surgical resection is the first choice of treatment.
基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2015187)the“Strategic Priority Research Program(B)”of the Chinese Academy of Sciences(Grant No.XDB30000000)the National Natural Science Foundation of China(Grant Nos.11704395 and 11204338)。
文摘We report an in-depth investigation on the out-of-plane lower critical field Hc1 of the KCa2(Fe1-xCox)4As4F2(12442-type,x=0,0.1).The multi-gap feature is revealed by the kink in the temperature-dependent Hc1(T)curve for the two samples with different doping levels.Based on a simplified two-gap model,the magnitudes of the two gaps are determined to beΔ1=1.2 meV andΔ2=5.0 meV for the sample with x=0,Δ1=0.86 meV andΔ2=2.8 meV for that with x=0.1.With the cobalt doping,the ratio of energy gap to critical transition temperature(Δ/kBTc)remains almost unchanged for the smaller gap and is suppressed by 20%for the larger gap.For the undoped KCa2Fe4As4F2,the obtained gap sizes are generally consistent with the results of angle-resolved photoemission spectroscopy experiments.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB632506)the National Natural Science Foundation of China(Grant Nos.51501105,51672159,and 51611540342)+4 种基金the Young Scholars Program of Shandong University(Grant No.2015WLJH21)the China Postdoctoral Science Foundation(Grant Nos.2015M580588 and 2016T90631)the Postdoctoral Innovation Foundation of Shandong Province,China(Grant No.201603027)the Fundamental Research Funds of Shandong University(Grant No.2015TB019)the Foundation of the State Key Laboratory of Metastable Materials Science and Technology(Grant No.201703)
文摘The thermoelectric materials have been considered as a potential candidate for the new power generation technology based on their reversible heat and electricity conversion.Lead telluride(Pb Te) is regarded as an excellent mid-temperature thermoelectric material due to its suitable intrinsic thermoelectric properties.So tremendous efforts have been done to improve the thermoelectric performance of Pb Te,and figures of merit,z_T > 2.0,have been reported.Main strategies for optimizing the thermoelectric performance have been focused as the main line of this review.The band engineering and phonon scattering engineering as two main effective strategies are systemically summarized here.The band engineering,like band convergence,resonant levels,and band flatting have been addressed in improving the power factor.Additionally,phonon scattering engineerings,such as atomic-scale,nano-scale,meso-scale,and multi-scale phonon scatterings have been applied to reduce the thermal conductivity.Besides,some successful synergistic effects based on band engineerings and phonon scatterings are illustrated as a simultaneous way to optimize both the power factor and thermal conductivity.Summarizing the above three main parts,we point out that the synergistic effects should be effectively exploited,and these may further boost the thermoelectric performance of Pb Te alloys and can be extended to other thermoelectric materials.
基金supported by the National Natural Science Foundation of China(21908062)。
文摘A computational study was carried out on bubble dynamic behaviors and bubble size distributions in a pressurized lab-scale gas-solid fluidized bed of Geldart A particles.High-resolution 3-D numerical simulations were performed using the two-fluid model based on the kinetic theory of granular flow.A finegrid,which is in the range of 3–4 particle diameters,was utilized in order to capture bubble structures explicitly without breaking down the continuum assumption for the solid phase.A novel bubble tracking scheme was developed in combination with a 3-D detection and tracking algorithm(MS3 DATA)and applied to detect the bubble statistics,such as bubble size,location in each time frame and relative position between two adjacent time frames,from numerical simulations.The spatial coordinates and corresponding void fraction data were sampled at 100 Hz for data analyzing.The bubble coalescence/break-up frequencies and the daughter bubble size distribution were evaluated by using the new bubble tracking algorithm.The results showed that the bubble size distributed non-uniformly over cross-sections in the bed.The equilibrium bubble diameter due to bubble break-up and coalescence dynamics can be obtained,and the bubble rise velocity follows Davidson’s correlation closely.Good agreements were obtained between the computed results and that predicted by using the bubble break-up model proposed in our previous work.The computational bubble tracking method showed the potential of analyzing bubble motions and the coalescence and break-up characteristics based on time series data sets of void fraction maps obtained numerically and experimentally.
基金Supported by National Natural Science Foundation of China(Grant Nos.61403232,61327003)Shandong Provincial Natural Science Foundation of China(Grant No.ZR2014FQ025)Young Scholars Program of Shandong University,China(YSPSDU,2015WLJH30)
文摘Detection of structural changes from an operational process is a major goal in machine condition monitoring. Existing methods for this purpose are mainly based on retrospective analysis, resulting in a large detection delay that limits their usages in real applications. This paper presents a new adaptive real-time change detection algorithm, an extension of the recent research by combining with an incremental sliding-window strategy, to handle the multi-change detection in long-term monitoring of machine operations. In particular, in the framework, Hilbert space embedding of distribution is used to map the original data into the Re-producing Kernel Hilbert Space(RKHS) for change detection; then, a new adaptive threshold strategy can be developed when making change decision, in which a global factor(used to control the coarse-to-fine level of detection) is introduced to replace the fixed value of threshold. Through experiments on a range of real testing data which was collected from an experimental rotating machinery system, the excellent detection performances of the algorithm for engineering applications were demonstrated. Compared with state-ofthe-art methods, the proposed algorithm can be more suitable for long-term machinery condition monitoring without any manual re-calibration, thus is promising in modern industries.
基金This work is supported by the National Key R&D Program of China(No.2018YFC1504203)the National Natural Science Foundation of China(No.42021003).
文摘The 2018 M_(W)6.7 Iburi earthquake shocked the eastern Iburi region to the west of the Hidaka Collision Zone in Hokkaido,which is a destructive inland earthquake.We resolved the kinematic rupture process of the event by combining strong motions(SM)and synthetic aperture radar(SAR)images in a joint inversion.The results reveal that the duration of the whole rupture is about 17s,yielding a total seismic moment of 1.4×10^(19)N·m(M_(W)=6.7).The main slip area is located at a depth of approximately 24 km with a peak slip of~0.8m above the hypocenter.The comparison with the regional velocity model shows the earthquake was initiated in the upper mantle,while the majority of slips are located in the lower crust,which is an“aseismic”domain in the typical sandwich model.The location of the major slip area is consistent with a high-conductivity volume.We proposed a mechanism of low frictional property(<0.3)produced by high pore pressure to explain the abnormal high dip angle and centroid depth located in the ductile lower-crust.Aftershocks are distributed in areas where the Coulomb frictional stress increases due to co-seismic displacement with a mechanism conjugating to the mainshock.
基金supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0305602,2022YFA1403203,and 2017YFA0303201)the National Natural Science Foundation of China(Grant Nos.12074002,92265104,12022413,11674331,and 12104004)+2 种基金the“Strategic Priority Research Program(B)”of the Chinese Academy of Sciences(Grant No.XDB33030100)the Major Basic Program of Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)supported by the High Magnetic Field Laboratory of Anhui Province,China。
文摘To reveal the intrinsic properties of the basic superconducting units,i.e.,the single layered FeSe/FeAs in iron-based superconductors or CuO_(2) planes in cuprate superconductors,is a necessary prerequisite for understanding the mechanism of high-Tc superconductivity.Up to now,an isolated FeAs layer has rarely been studied due to the difficulty in materials synthesis.Here,we report a scanning tunneling microscopy/spectroscopy(STM/STS)study on the iron-based superconductor KCa_(2)Fe_(4)As_(4)F_(2).In situ cleavage produced a single FeAs layer covered by a reconstructed K surface,which is isolated from the bulk by the underlying CaF layer and shows multi-band superconductivity with a much lower T_(c) than its bulk counterpart.In the exposed As-terminated regions with coverage of scattered K atoms,a pseudogap was observed,leading to an inhomogeneous superconductivity without long-range phase coherence in real space,which is remarkably similar to the high-T_(c) cuprate superconductors.These results provide a new perspective to understanding the origin of superconductivity in iron-based superconductors.
基金the support by the National Natural Science Foundation of China(12047505)State Key Laboratory of Nuclear Physics and Technology,Peking University+4 种基金supported in part by the National Natural Science Foundation of China(12125501,12141501,and 11775002)National Key Research and Development Program of China(2020YFA0406400)supported in part by the National Natural Science Foundation of China(12070131001)supported in part by Chinese Academy of Sciences Interdisciplinary Innovation Team and the National Natural Science Foundation of China(11935017,12293060,and 12293063)partly supported by Highperformance Computing Platform of Peking University。
