A review of understanding electrocatalytic reactions in energy conversion and energy storage systems via scanning electrochemical microscopy

To address climate change and promote environmental sustainability,electrochemical energy conversion and storage systems emerge as promising alternative to fossil fuels,catering to the escalating demand for energy.Achieving optimal energy efficiency and cost competitiveness in these systems requires the strategic design of electrocatalysts,coupled with a thorough comprehension of the underlying mechanisms and degradation behavior occurring during the electrocatalysis processes.Scanning electrochemical microscopy(SECM),an analytical technique for studying surface electrochemically,stands out as a powerful tool offering electrochemical insights.It possesses remarkable spatiotemporal resolution,enabling the visualization of the localized electrochemical activity and surface topography.This review compiles crucial research findings and recent breakthroughs in electrocatalytic processes utilizing the SECM methodology,specifically focusing on applications in electrolysis,fuel cells,and metal–oxygen batteries within the realm of energy conversion and storage systems.Commencing with an overview of each energy system,the review introduces the fundamental principles of SECM,and aiming to provide new perspectives and broadening the scope of applied research by describing the major research categories within SECM.

Investigation of reflection anisotropy induced by micropipe defects on the surface of a 4H-SiC single crystal using scanning anisotropy microscopy

Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy(SAM)system.The reflection anisotropy(RA)image with a'butterfly pattern'is obtained around the micropipes by SAM.The RA image of the edge dislocations is theoretically simulated based on dislocation theory and the photoelastic principle.By comparing with the Raman spectrum,it is verified that the micropipes consist of edge dislocations.The different patterns of the RA images are due to the different orientations of the Burgers vectors.Besides,the strain distribution of the micropipes is also deduced.One can identify the dislocation type,the direction of the Burgers vector and the optical anisotropy from the RA image by using SAM.Therefore,SAM is an ideal tool to measure the optical anisotropy induced by the strain field around a defect.

Fatigue properties and damage constitutive model of salt rock based on CT scanning

To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning instrument.Based on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were analyzed.The failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane porosity.The damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle number.In order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further established.The results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading.

Uniformity Control of Scanned Beam in 300 MeV Proton and Heavy Ion Accelerator Complex at SESRI

In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiation area is required for the extracted ion beams,which is crucial because it directly affects the experimental precision and therapeutic effect.Specifically,ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design.In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure(SESRI),proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals.In order to achieve the required large irradiation area of 320 mm×320 mm,horizontal and vertical scanning magnets are used in the extraction beam line.However,considering the various requirements for beam species and energies,the tracking accuracy of power supplies(PSs),the eddy current effect of scanning magnets,and the fluctuation of ion bunch structure will reduce the irradiation uniformity.To mitigate these effects,a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI.In the experiment,the uniformity is successfully optimized from 75%to over 90%after five iterations of adjustment to the PS waveforms.In this paper,the method and experimental results were introduced.

Acousto-optic scanning multi-photon lithography with high printing rate

As a manufacturing method that is focused on end-users,3D printing has gained a lot of attention in recent years due to its unique advantages in fabricating complex three-dimensional structures.Various new micro-nano 3D printing methods have been developed to meet the demand for high-precision and high-yield manufacturing1-9.Among them,multi-photon-photon lithography(MPL) is a promising 3D nanofabrication technology due to its capability of true 3D digital processing and nanoscale processing resolution beyond the diffraction limit.It has been widely used to fabricate microoptics10,11,photonic crystals12,microfluidics13,meta-surfaces14,and mechanical metamaterials15.

Three-dimensional finite element simulation and reconstruction of jointed rock models using CT scanning and photogrammetry

The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.

Algorithm of automatic identification of diabetic retinopathy foci based on ultra-widefield scanning laser ophthalmoscopy

AIM:To propose an algorithm for automatic detection of diabetic retinopathy(DR)lesions based on ultra-widefield scanning laser ophthalmoscopy(SLO).METHODS:The algorithm utilized the FasterRCNN(Faster Regions with CNN features)+ResNet50(Residua Network 50)+FPN(Feature Pyramid Networks)method for detecting hemorrhagic spots,cotton wool spots,exudates,and microaneurysms in DR ultra-widefield SLO.Subimage segmentation combined with a deeper residual network FasterRCNN+ResNet50 was employed for feature extraction to enhance intelligent learning rate.Feature fusion was carried out by the feature pyramid network FPN,which significantly improved lesion detection rates in SLO fundus images.RESULTS:By analyzing 1076 ultra-widefield SLO images provided by our hospital,with a resolution of 2600×2048 dpi,the accuracy rates for hemorrhagic spots,cotton wool spots,exudates,and microaneurysms were found to be 87.23%,83.57%,86.75%,and 54.94%,respectively.CONCLUSION:The proposed algorithm demonstrates intelligent detection of DR lesions in ultra-widefield SLO,providing significant advantages over traditional fundus color imaging intelligent diagnosis algorithms.

Optical scanning endoscope via a single multimode optical fiber

Optical endoscopy has become an essential diagnostic and therapeutic approach in modern biomedicine for directly observing organs and tissues deep inside the human body,enabling non-invasive,rapid diagnosis and treatment.Optical fiber endoscopy is highly competitive among various endoscopic imaging techniques due to its high flexibility,compact structure,excellent resolution,and resistance to electromagnetic interference.Over the past decade,endoscopes based on a single multimode optical fiber(MMF)have attracted widespread research interest due to their potential to significantly reduce the footprint of optical fiber endoscopes and enhance imaging capabilities.In comparison with other imaging principles of MMF endoscopes,the scanning imaging method based on the wavefront shaping technique is highly developed and provides benefits including excellent imaging contrast,broad applicability to complex imaging scenarios,and good compatibility with various well-established scanning imaging modalities.In this review,various technical routes to achieve light focusing through MMF and procedures to conduct the scanning imaging of MMF endoscopes are introduced.The advancements in imaging performance enhancements,integrations of various imaging modalities with MMF scanning endoscopes,and applications are summarized.Challenges specific to this endoscopic imaging technology are analyzed,and potential remedies and avenues for future developments are discussed.

T-Scan咬合分析系统在口腔治疗中的研究进展

在口腔临床治疗中,咬合功能的测量和分析对治疗发挥不可忽略的作用,而以往测量咬合状态的方法受口腔医师主观影响,准确性不高,无法量化。大量研究显示T-Scan咬合分析系统能精确测量不同咬合状态下的咬合力与时间实时的关系,精确记录咬合接触时间、力量、面积,并动态分析咬合接触情况。在颞颌关节紊乱疾病、正畸正颌、修复和种植、牙周病等多种口腔疾病治疗中,该系统协助临床医生执行精确和有针对性的咬合诊断和调整,并通过可预测和数值测量的治疗结果评价减少咬合并发症发生,获得良好的治疗效果。该系统量化的数据以可视化的方式展示出来,可最大限度地促进医患沟通,更能满足现代口腔疾病临床治疗的需求。本文就T-Scan咬合分析系统的特点及其在口腔临床中的应用进展做一综述。

A Novel Secure Scan Design Based on Delayed Physical Unclonable Function

The advanced integrated circuits have been widely used in various situations including the Internet of Things,wireless communication,etc.But its manufacturing process exists unreliability,so cryptographic chips must be rigorously tested.Due to scan testing provides high test coverage,it is applied to the testing of cryptographic integrated circuits.However,while providing good controllability and observability,it also provides attackers with a backdoor to steal keys.In the text,a novel protection scheme is put forward to resist scan-based attacks,in which we first use the responses generated by a strong physical unclonable function circuit to solidify fuseantifuse structures in a non-linear shift register(NLSR),then determine the scan input code according to the configuration of the fuse-antifuse structures and the styles of connection between the NLSR cells and the scan cells.If the key is right,the chip can be tested normally;otherwise,the data in the scan chain cannot be propagated normally,it is also impossible for illegal users to derive the desired scan data.The proposed technique not only enhances the security of cryptographic chips,but also incurs acceptable overhead.

In situ observation of the dissolution kinetics of Al_(2)O_(3) particles in CaO–Al_(2)O_(3)–SiO_(2) slags using laser confocal scanning microscopy

The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K.The results show that the controlling step during the Al_(2)O_(3) dissolution was the diffusionin molten slag.It was found that the dissolution curves of Al_(2)O_(3) particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al_(2)O_(3) ratio of slag.A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al_(2)O_(3) in slag.Diffusion coefficients of Al_(2)O_(3) in slag were calculated as 2.8×10to 4.1×10m~2/s at the temperature of 1773-1873 K.The dissolution rate of Al_(2)O_(3) increased with higher temperature,CaO/Al_(2)O_(3),and particle size.A new model was shown to be v_(Al_(2)O_(3))=0.16×r_(0)^(1.58)×x^(3.52)×(T-T_(mp))^(1.11)to predict the dissolution rate and the total dissolution time of Al_(2)O_(3) inclusions with various sizes,where vAl_(2)O_(3) is the dissolution rate of Al_(2)O_(3) in volume,μm^(3)/s;x is the value of CaO/Al_(2)O_(3) mass ratio;R_(0) is the initial radius of Al_(2)O_(3),μm;T is the temperature,K;T_(mp) is the melting point of slag,K.

Acousto-optic scanning spatial-switching multiphoton lithography

Nano-3D printing has obtained widespread attention owing to its capacity to manufacture end-use components with nano-scale features in recent years.Multiphoton lithography(MPL)is one of the most promising 3D nanomanufacturing technologies,which has been widely used in manufacturing micro-optics,photonic crystals,microfluidics,meta-surface,and mechanical metamaterials.Despite of tremendous potential of MPL in laboratorial and industrial applications,simultaneous achievement of high throughput,high accuracy,high design freedom,and a broad range of material structuring capabilities remains a long-pending challenge.To address the issue,we propose an acousto-optic scanning with spatial-switching multispots(AOSS)method.Inertia-free acousto-optic scanning and nonlinear swept techniques have been developed for achieving ultrahigh-speed and aberration-free scanning.Moreover,a spatial optical switch concept has been implemented to significantly boost the lithography throughput while maintaining high resolution and high design freedom.An eight-foci AOSS system has demonstrated a record-high 3D printing rate of 7.6×10^(7)voxel s^(-1),which is nearly one order of magnitude higher than earlier scanning MPL,exhibiting its promise for future scalable 3D nanomanufacturing.

Automatic identification of rock discontinuity and stability analysis of tunnel rock blocks using terrestrial laser scanning

Local geometric information and discontinuity features are key aspects of the analysis of the evolution and failure mechanisms of unstable rock blocks in rock tunnels.This study demonstrates the integration of terrestrial laser scanning(TLS)with distinct element method for rock mass characterization and stability analysis in tunnels.TLS records detailed geometric information of the surrounding rock mass by scanning and collecting the positions of millions of rock surface points without contact.By conducting a fuzzy K-means method,a discontinuity automatic identification algorithm was developed,and a method for obtaining the geometric parameters of discontinuities was proposed.This method permits the user to visually identify each discontinuity and acquire its spatial distribution features(e.g.occurrences,spac-ings,trace lengths)in great detail.Compared with hand mapping in conventional geotechnical surveys,the geometric information of discontinuities obtained by this approach is more accurate and the iden-tification is more efficient.Then,a discrete fracture network with the same statistical characteristics as the actual discontinuities was generated with the distinct element method,and a representative nu-merical model of the jointed surrounding rock mass was established.By means of numerical simulation,potential unstable rock blocks were assessed,and failure mechanisms were analyzed.This method was applied to detection and assessment of unstable rock blocks in the spillway and sand flushing tunnel of the Hongshiyan hydropower project after a collapse.The results show that the noncontact detection of blocks was more labor-saving with lower safety risks compared with manual surveys,and the stability assessment was more reliable since the numerical model built by this method was more consistent with the distribution characteristics of actual joints.This study can provide a reference for geological survey and unstable rock block hazard mitigation in tunnels subjected to complex geology and active rockfalls.

ZSCAN4在早期胚胎及多能干细胞中的作用及调节机制

含有锌指和SCAN结构域的蛋白质4(zinc finger and SCAN domain containing 4,ZSCAN4)在2细胞期胚胎以及胚胎干细胞中作为DNA结合蛋白质特异性表达。ZSCAN4能够调控早期胚胎发育过程,在合子基因组激活(zygotic genome activation,ZGA)期间通过促进DNA损伤修复和纠正染色体异常,以维持植入前胚胎的基因组和染色体完整性。在小鼠胚胎干细胞(mouse embryonic stem cells,mESCs)向2细胞样细胞转换期间,ZSCAN4与ATP依赖性染色质重塑因子相互作用,调节鼠内源性逆转录病毒L(murine endogenous retrovirus L,MERVL)增强子的活性,激活周边的2细胞期基因的表达,促进胚胎干细胞向2细胞样细胞的转变。ZSCAN4还能通过降低DNA甲基化水平同时介导异染色质沉默,并促使端粒重组和端粒延伸,保持基因组稳定性,进一步维持多能干细胞的无限自我更新能力和多能性,促进mESCs向胚胎2细胞样细胞转变。此外,ZSCAN4还能在重编程中重新激活早期胚胎基因,显著提高诱导多能干细胞(induced pluripotent stem cells,iPSCs)的产生效率,降低iPSCs形成过程中的DNA损伤,并通过延长端粒保持基因组稳定性,从而促进无遗传缺陷和高质量iPSCs的生成。该文围绕ZSCAN4调控早期胚胎发育过程、介导多能干细胞的端粒延长以及在体细胞重编程中的作用等生物学功能展开论述,以期为早期胚胎发育、多能干细胞的维持以及重编程技术的优化提供参考。

Correlating the Interfacial Polar-Phase Structure to the Local Chemistry in Ferroelectric Polymer Nanocomposites by Combined Scanning Probe Microscopy

Ferroelectric polymer nanocomposites possess exceptional electric properties with respect to the two otherwise uniform phases,which is commonly attributed to the critical role of the matrix-particle interfacial region.However,the structure-property correlation of the interface remains unestablished,and thus,the design of ferroelectric polymer nanocompos-ite has largely relied on the trial-and-error method.Here,a strategy that combines multi-mode scanning probe microscopy-based electrical charac-terization and nano-infrared spectroscopy is developed to unveil the local structure-property correlation of the interface in ferroelectric polymer nano-composites.The results show that the type of surface modifiers decorated on the nanoparticles can significantly influence the local polar-phase content and the piezoelectric effect of the polymer matrix surrounding the nano-particles.The strongly coupled polar-phase content and piezoelectric effect measured directly in the interfacial region as well as the computed bonding energy suggest that the property enhancement originates from the formation of hydrogen bond between the surface modifiers and the ferroelectric polymer.It is also directly detected that the local domain size of the ferroelectric polymer can impact the energy level and distribution of charge traps in the interfacial region and eventually influence the local dielectric strength.

Thermoacoustic imaging:From single-element scanning to portable and array-based imaging

The microwave-induced thermoacoustic imaging(TAI)technology has both the advantages of high contrast of microwave imaging and high resolution of ultrasound imaging(UI),so it has carried out exploratory application research in various areas,such as the early detection of breast tumors and cerebrovascular diseases.However,the microwave generator used in the traditional TAI technology is huge and expensive,and the temporal resolution is also too low due to the single-element scanning mechanism.Thus,it is difficult to meet the needs of clinical applications.In this paper,the iterative process and the analysis of related application scenarios from single-element scanning to portable and array-based TAI,such as the miniaturized microwave generator,handheld antenna,multi-channel data acquisition,and UI/TAIdual-modality imaging,are reviewed,and the future trends of this technology are discussed.This review helps researchers in the field of TAI learn the technological development process and future trends.It also deepens clinicians’understanding of TAI so as to put forward more application requirements.

Temperature Field in Laser Line Scanning Thermography: Analytical Calculation and Experiment

The temperature field in laser line scanning thermography is investigated comprehensively in this work,including analytical calculation and experiment.Firstly,the principle of laser line scanning thermography is analyzed.On this basis,a physical laser line scanning model is proposed.Afterwards,based on Fourier transform(FT)and segregation variablemethod(SVM),the heat conduction differential equation in laser line scanning thermography is derived in detail.The temperature field of the composite-based coatings model with defects is simulated numerically.The results show that the laser line scanning thermography can effectively detect the defects in the model.The correctness of the analytical calculation is verified by comparing the surface temperature distribution obtained by analytical calculation and numerical simulation.Additionally,an experiment is carried out and the changeable surface temperature obtained by analytical calculation is compared with the experimental results.It shows that the error of maximum temperature obtained by analytical calculation and by experiment is 8%with high accuracy,which proves the correctness of analytical calculation and enriches the theoretical foundation of laser line scanning thermography.

Application of 3D Scanned Big Data of Large-scale Cultural Heritage Objects Based on Noise-robust Transparent Visualization

Three-dimensional(3D) scanning technology has undergone remarkable developments in recent years.Data acquired by 3D scanning have the form of 3D point clouds.The 3D scanned point clouds have data sizes that can be considered big data.They also contain measurement noise inherent in measurement data.These properties of 3D scanned point clouds make many traditional CG/visualization techniques difficult.This paper reviewed our recent achievements in developing varieties of high-quality visualizations suitable for the visual analysis of 3D scanned point clouds.We demonstrated the effectiveness of the method by applying the visualizations to various cultural heritage objects.The main visualization targets used in this paper are the floats in the Gion Festival in Kyoto(the float parade is on the UNESCO Intangible Cultural Heritage List) and Borobudur Temple in Indonesia(a UNESCO World Heritage Site).

Improving Yolo5 for Real-Time Detection of Small Targets in Side Scan Sonar Images

Side scan sonar(SSS)is an important means to detect and locate seafloor targets.Autonomous underwater vehicles(AUVs)carrying SSS stay near the seafloor to obtain high-resolution images and provide the outline of the target for observers.The target feature information of an SSS image is similar to the background information,and a small target has less pixel information;therefore,accu-rately identifying and locating small targets in SSS images is challenging.We collect the SSS images of iron metal balls(with a diameter of 1m)and rocks to solve the problem of target misclassification.Thus,the dataset contains two types of targets,namely,‘ball’and‘rock’.With the aim to enable AUVs to accurately and automatically identify small underwater targets in SSS images,this study designs a multisize parallel convolution module embedded in state-of-the-art Yolo5.An attention mechanism transformer and a convolutional block attention module are also introduced to compare their contributions to small target detection accuracy.The performance of the proposed method is further evaluated by taking the lightweight networks Mobilenet3 and Shufflenet2 as the backbone network of Yolo5.This study focuses on the performance of convolutional neural networks for the detection of small targets in SSS images,while another comparison experiment is carried out using traditional HOG+SVM to highlight the neural network’s ability.This study aims to improve the detection accuracy while ensuring the model efficiency to meet the real-time working requirements of AUV target detection.

Method for visualizing the shear process of rock joints using 3D laser scanning and 3D printing techniques

This study presents a visualized approach for tracking joint surface morphology.Three-dimensional laser scanning(3DLS)and 3D printing(3DP)techniques are adopted to record progressive failure during rock joint shearing.The 3DP resin is used to create transparent specimens to reproduce the surface morphology of a natural joint precisely.The freezing method is employed to enhance the mechanical properties of the 3DP specimens to reproduce the properties of hard rock more accurately.A video camera containing a charge-coupled device(CCD)camera is utilized to record the evolution of damaged area of joint surface during the direct shear test.The optimal shooting distance and shooting angle are recommended to be 800 mm and 40?,respectively.The images captured by the CCD camera are corrected to quantitatively describe the damaged area on the joint surface.Verification indicates that this method can accurately describe the total sheared areas at different shear stages.These findings may contribute to elucidating the shear behavior of rock joints.