Aimed at the long and narrow geometric features and poor generalization ability of the damage detection in conveyor belts with steel rope cores using the X-ray image,a detection method of damage X-ray image is propose...Aimed at the long and narrow geometric features and poor generalization ability of the damage detection in conveyor belts with steel rope cores using the X-ray image,a detection method of damage X-ray image is proposed based on the improved fully convolutional one-stage object detection(FCOS)algorithm.The regression performance of bounding boxes was optimized by introducing the complete intersection over union loss function into the improved algorithm.The feature fusion network structure is modified by adding adaptive fusion paths to the feature fusion network structure,which makes full use of the features of accurate localization and semantics of multi-scale feature fusion networks.Finally,the network structure was trained and validated by using the X-ray image dataset of damages in conveyor belts with steel rope cores provided by a flaw detection equipment manufacturer.In addition,the data enhancement methods such as rotating,mirroring,and scaling,were employed to enrich the image dataset so that the model is adequately trained.Experimental results showed that the improved FCOS algorithm promoted the precision rate and the recall rate by 20.9%and 14.8%respectively,compared with the original algorithm.Meanwhile,compared with Fast R-CNN,Faster R-CNN,SSD,and YOLOv3,the improved FCOS algorithm has obvious advantages;detection precision rate and recall rate of the modified network reached 95.8%and 97.0%respectively.Furthermore,it demonstrated a higher detection accuracy without affecting the speed.The results of this work have some reference significance for the automatic identification and detection of steel core conveyor belt damage.展开更多
Fracture identification is important for the evaluation of carbonate reservoirs. However, conventional logging equipment has small depth of investigation and cannot detect rock fractures more than three meters away fr...Fracture identification is important for the evaluation of carbonate reservoirs. However, conventional logging equipment has small depth of investigation and cannot detect rock fractures more than three meters away from the borehole. Remote acoustic logging uses phase-controlled array-transmitting and long sound probes that increase the depth of investigation. The interpretation of logging data with respect to fractures is typically guided by practical experience rather than theory and is often ambiguous. We use remote acoustic reflection logging data and high-order finite-difference approximations in the forward modeling and prestack reverse-time migration to image fractures. First, we perform forward modeling of the fracture responses as a function of the fracture-borehole wall distance, aperture, and dip angle. Second, we extract the energy intensity within the imaging area to determine whether the fracture can be identified as the formation velocity is varied. Finally, we evaluate the effect of the fracture-borehole distance, fracture aperture, and dip angle on fracture identification.展开更多
Scintillation semiconductors play increasingly important medical diagnosis and industrial inspection roles.Recently,two-dimensional(2D)perovskites have been shown to be promising materials for medical X-ray imaging,bu...Scintillation semiconductors play increasingly important medical diagnosis and industrial inspection roles.Recently,two-dimensional(2D)perovskites have been shown to be promising materials for medical X-ray imaging,but they are mostly used in low-energy(≤130 keV)regions.Direct detection of MeV X-rays,which ensure thorough penetration of the thick shell walls of containers,trucks,and aircraft,is also highly desired in practical industrial applications.Unfortunately,scintillation semiconductors for high-energy X-ray detection are currently scarce.Here,This paper reports a 2D(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single crystal with outstanding sensitivity and stability toward X-ray radiation that provides an ultra-wide detectable X-ray range of between 8.20 nGy_(air)s^(-1)(50 keV)and 15.24 mGy_(air)s^(-1)(9 MeV).The(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single-crystal detector with a vertical structure is used for high-performance X-ray imaging,delivering a good spatial resolution of 4.3 Ip mm^(-1)in a plane-scan imaging system.Low ionic migration in the 2D perovskite enables the vertical device to be operated with hundreds of keV to MeV X-ray radiation at high bias voltages,leading to a sensitivity of 46.90μC Gy_(air)-1 cm^(-2)(-1.16 Vμm^(-1))with 9 MeV X-ray radiation,demonstrating that 2D perovskites have enormous potential for high-energy industrial applications.展开更多
X-ray andγ-ray detectors are widely used in medical,military,security,material analysis,and industrial inspection.In recent years,perovskite materials have become promising materials for radiation detection owing to ...X-ray andγ-ray detectors are widely used in medical,military,security,material analysis,and industrial inspection.In recent years,perovskite materials have become promising materials for radiation detection owing to their strong stopping power,considerable carrier transportation ability,and simple synthesis process.Previous studies have demonstrated both direct and indirect radiation detectors using perovskite materials.In this review,we aim to elucidate the mechanism by which X-rays andγ-rays interact with matter,explain the principles of the energy integrating mode and photon counting mode for direct detection,and discuss the key factors determining device performance.Furthermore,we summarize recent advances in perovskite-based radiation detectors for both modes.Additionally,we identify challenges that need to be overcome to enable perovskite materials to be successfully commercialized.展开更多
The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites(MHPs)and their derivatives,which possess remarkable light yield and X-ray ...The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites(MHPs)and their derivatives,which possess remarkable light yield and X-ray sensitivity.This comprehensive review delves into cutting-edge approaches for optimizing MHP scintillators performances by enhancing intrinsic physical properties and employing engineering radioluminescent(RL)light strategies,underscoring their potential for developing materials with superior high-resolution X-ray detection and imaging capabilities.We initially explore into recent research focused on strategies to effectively engineer the intrinsic physical properties of MHP scintillators,including light yield and response times.Additionally,we explore innovative engineering strategies involving stacked structures,waveguide effects,chiral circularly polarized luminescence,increased transparency,and the fabrication of flexile MHP scintillators,all of which effectively manage the RL light to achieve high-resolution and high-contrast X-ray imaging.Finally,we provide a roadmap for advancing next-generation MHP scintillators,highlighting their transformative potential in high-performance X-ray detection systems.展开更多
In real-world scenarios,dual-view X-ray machines have outnumbered single-view X-ray machines due to their ability to provide comprehensive internal information about the baggage,which is important for identifying proh...In real-world scenarios,dual-view X-ray machines have outnumbered single-view X-ray machines due to their ability to provide comprehensive internal information about the baggage,which is important for identifying prohibited items that are not visible in one view due to rotation or overlap.However,existing work still focuses mainly on single-view,and the limited dual-viewbasedwork only performs simple information fusion at the feature or decision level and lacks effective utilization of the complementary information hidden in dual view.To this end,this paper proposes an end-to-end dual-view prohibited item detection method,the core of which is an adaptive material-aware coordinate-aligned attention module(MACA)and an adaptive adjustment strategy(AAS).Specifically,we observe that in X-ray images,the material information of an object can be represented by color and texture features,and remains consistent across views,even under complex backgrounds.Therefore,our MACA first integrates the material information of the prohibited items in each view and then smoothly transfers these clearmaterial clues along the shared axis to the corresponding locations in the other view to enhance the feature representation of the blurred prohibited items in the other view.In addition,AAS can autonomously adjust the importance of the two views during feature learning to make joint optimizationmore stable and effective.Experiments on the DvXray dataset demonstrate that the proposed MACA and AAS can be plug-and-played into various detectors,such as Faster Region-based Convolutional Neural Network(Faster R-CNN)and Fully Convolutional One-Stage Object Detector(FCOS),and bring consistent performance gains.The entire framework performs favorably against state-of-the-art methods,especially on small-sized prohibited items,highlighting its potential application in reality.展开更多
Synchrotron method of resonant X-ray reflectivity 2D mapping has been applied to study ultrathin epitaxial layers of WS_(2)grown by pulsed laser deposition on Al_(2)O_(3)(0001)substrates.The measurements were carried ...Synchrotron method of resonant X-ray reflectivity 2D mapping has been applied to study ultrathin epitaxial layers of WS_(2)grown by pulsed laser deposition on Al_(2)O_(3)(0001)substrates.The measurements were carried out across the L absorption edge of tungsten to perform depth-dependent element-selective analysis sensitive to potential chemical modification of the WS_(2)layer in ambient conditions.Despite the few monolayer thickness of the studied film,the experimentally measured maps of reflectance as a function of incident angle and photon energy turned out to be quite informative showing well-pronounced interference effects near W absorption edge at 10210 eV.The synchrotron studies were complemented with conventional non-resonant reflectance measurements carried out in the laboratory at a fixed photon energy corresponding to Cu Kαemission.The reconstruction of the depth and energy dependent scattering length density within the studied multilayers was carried out using the OpenCL empowered fitting software utilizing spectral shaping algorithm which does not rely on the pre-measured reference absorption spectra.A thin WO_(x) layer has been revealed at the surface of the WS_(2)layer pointing out to the effect of water assisted photo-oxidation reported in a number of works related to ultrathin layers of transition metal dichalcogenides.展开更多
Lead-halide perovskites exhibit outstanding performance in X-ray detection due to their intrinsic features such as high charge carrier mobility,large atomic number,and long carrier lifetime,but the toxicity of lead is...Lead-halide perovskites exhibit outstanding performance in X-ray detection due to their intrinsic features such as high charge carrier mobility,large atomic number,and long carrier lifetime,but the toxicity of lead is regarded as the major factor hindering their development.Here,we introduce organic molecule(R)-(-)-2-methylpiperazine(R-MPz)into the bismuth-based structure to synthesize lead-free(R)-(H_(2)MPz)BiI_(5)(R-MBI).The high-quality centimeter-sized single crystals have been obtained,which show a low dark current and superior environmental stability.Particularly,the single-crystal device of R-MBI exhibits a highμτproduct up to 1.88×10^(-4)cm^(2)/V and a low trap density of 1.21×10^(10)cm^(-3).Further,the detector displays excellent detection sensitivity of 263.58μC Gy_(air)^(-1)cm^(-2)and a favorable low detection limit of 4.35μGyair/s,both of which meet the requirement for medical diagnostics.These findings shed light on the exploration of innovative bismuth-based hybrid perovskites for high-performance X-ray detection.展开更多
Direct X-ray detectors,which directly convert X-rays into electrical signals through semiconductors,have higher space solution than scintillator-mediated indirect X-ray ones and are high desirable for early cancer det...Direct X-ray detectors,which directly convert X-rays into electrical signals through semiconductors,have higher space solution than scintillator-mediated indirect X-ray ones and are high desirable for early cancer detection and other applications,but the mainstream commercialα-Se detector is still largely limited by high production costs,large leakage current and low stability.This article reports an easily prepared,stable radiochromic semiconductive metal–organic framework(MOF),(MV)[Cd_(3)(tdc)_(4)]·2H_(2)O(RCS-1,H_(2)tdc=2,5-thiophenedicarboxylic acid;MV^(2+)=methyl viologen cation)with direct X-ray detecting ability.With a large bulk resistivity of 8.40×10^(9)Ωcm,this material ensures minimal dark current and low noise for X-ray detection.Additionally,it exhibits higher sensitivity to W KαX-rays(98.58μC Gy^(-1)cm^(-2))thanα-Se(~20μC Gy^(-1)cm^(-2)).Meanwhile,unlike most reported direct X-ray detecting semiconductors,compound RCS-1 shows remarkable color change upon X-ray irradiation owing to the presence of photochromism-active viologen cations.This feature offers an appealing visual detecting ability to direct X-ray detectors that provide only the electrical signals.展开更多
X-ray detection plays a crucial role across various aspects of our daily lives,encompassing medical diagnoses,security screenings,and non-destructive examinations in industrial settings.Given the wide array of applica...X-ray detection plays a crucial role across various aspects of our daily lives,encompassing medical diagnoses,security screenings,and non-destructive examinations in industrial settings.Given the wide array of application contexts,a wealth of opportunities is entailed with the practical utilization of both organic and inorganic X-ray detection materials.A novel and promising contender in this realm is the emergence of metal-free organic halide perovskites(O-PVSKs),offering great opportunities and tremendous potential in X-ray detection.This potential can be attributed to the distinct crystalline configuration of O-PVSKs,where organic constituents are structured into an ABX3perovskite arrangement.Consequently,O-PVSKs exhibit captivating characteristics reminiscent of organic materials,such as lightweight nature and modifiability,all while retaining the distinctive traits associated with halide perovskites ranging from diverse structures to tunable optoelectronic properties.This review article delves into the intrinsic attributes of O-PVSKs and critically examines the viability of O-PVSKs in X-ray detection,through which key features that distinguish O-PVSKs from traditional organic semiconductors and perovskites are outlined.This is followed by a perspective given on their future avenues for exploration.展开更多
Baggage screening is crucial for airport security. This paper examines various algorithms for firearm detection in X-ray images of baggage. The focus is on identifying steel barrel bores, which are essential for deton...Baggage screening is crucial for airport security. This paper examines various algorithms for firearm detection in X-ray images of baggage. The focus is on identifying steel barrel bores, which are essential for detonation. For this, the study uses a set of 22,000 X-ray scanned images. After preprocessing with filtering techniques to improve image quality, deep learning methods, such as Convolutional Neural Networks (CNNs), are applied for classification. The results are also compared with Autoencoder and Random Forest algorithms. The results are validated on a second dataset, highlighting the advantages of the adopted approach. Baggage screening is a very important part of the risk assessment and security screening process at airports. Automating the detection of dangerous objects from passenger baggage X-ray scanners can speed up and increase the efficiency of the entire security procedure.展开更多
A ceramic ball is a basic part widely used in precision bearings.There is no perfect testing equipment for ceramic ball surface defects at present.A fast visual detection algorithm for ceramic ball surface defects bas...A ceramic ball is a basic part widely used in precision bearings.There is no perfect testing equipment for ceramic ball surface defects at present.A fast visual detection algorithm for ceramic ball surface defects based on fringe reflection is designed.By means of image preprocessing,grayscale value accumulative differential positioning,edge detection,pixel-value row difference and template matching,the algorithm can locate feature points and judge whether the spherical surface has defects by the number of points.Taking black silicon nitride ceramic balls with a diameter of 6.35 mm as an example,the defect detection time for a single gray scale image is 0.78 s,and the detection limit is 16.5μm.展开更多
Adhesion molecule CD146 (100-130kDa) belongs to the immunoglobulin super family and it is originally identified as a biomarker for melanoma. Recently, CD146 is found as
Metal nano layer coating for increasing the sensitivity of spectroscopic measurements is proposed and experimentally demonstrated in this paper. The metal nano layer will attract the micro-poisons from any measured aq...Metal nano layer coating for increasing the sensitivity of spectroscopic measurements is proposed and experimentally demonstrated in this paper. The metal nano layer will attract the micro-poisons from any measured aqueous sample increasing the concentration of the micro-poison in the vicinity of the surface and significantly improves the sensitivity of the spectroscopic measurement. The demonstration was carried out using Fourier Transform Infra-Red (FTIR) operating in the MIR 400 cm-1 - 4000 cm-1 and 5 nm Gold layer which was grown on silicon oxide substrate. In the experimental demonstration Malathion organophosphate pesticide was used as micro-poison. The spectroscopic measurement proves that Malathion was attracted to the metal nano layer. Furthermore, the absorption lines of Malathion were detected and recognized. This proof of principle can be applied to any Internal Reflection Elements (IRE) and it can be used to purify any aqueous solutions and atmosphere from micro-poisons which will be attracted to the metal Nano layer.展开更多
Halide perovskites have emerged as the next generation of optoelectronic materials and their remarkable performances have been attractive in the fields of solar cells,light-emitting diodes,photodetectors,etc.In additi...Halide perovskites have emerged as the next generation of optoelectronic materials and their remarkable performances have been attractive in the fields of solar cells,light-emitting diodes,photodetectors,etc.In addition,halide perovskites have been reported as an attractive new class of X-ray direct detecting materials recently,owning to the strong X-ray stopping capacity,excellent carrier transport,high sensitivity,and cost-effective manufacturing.Meanwhile,perovskite based direct Xray imagers have been successfully demonstrated as well.In this review article,we firstly introduced some fundamental principles of direct X-ray detection and imaging,and summarized the advances of perovskite materials for these purposes and finally put forward some needful and feasible directions.展开更多
Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of...Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.展开更多
A method for quantitative determination of fish sperm deoxyribonucleic acid(fsDNA)was developed by using titanium dioxide(TiO2)as an adsorbent and near-infrared diffuse reflectance spectroscopy(NIRDRS).The selective e...A method for quantitative determination of fish sperm deoxyribonucleic acid(fsDNA)was developed by using titanium dioxide(TiO2)as an adsorbent and near-infrared diffuse reflectance spectroscopy(NIRDRS).The selective enrichment of fsDNA was proved by comparing the adsorption efficiency of bovine serum albumin,tyrosine and tryptophan,and the low adsorption background of TiO2 was illustrated by comparing the spectra of four commonly-used inorganic adsorbents(alkaline aluminium oxide,neutral aluminium oxide,nano-hydroxyapatite and silica).The spectral feature of fsDNA can be clearly observed in the spectrum of the sample.Partial least squares(PLS)model was built for quantitative determination of fsDNA using 28 solutions,and 13 solutions with interferences were used for validation of the model.The results showed that the correlation coefficient(R)between the predicted and the reference concentration is 0.9727 and the recoveries of the validation samples are in the range of 98.2%-100.7%.展开更多
A first and effective method is proposed to detect weld deject adaptively in various Dypes of real-time X-ray images obtained in different conditions. After weld extraction and noise reduction, a proper template of me...A first and effective method is proposed to detect weld deject adaptively in various Dypes of real-time X-ray images obtained in different conditions. After weld extraction and noise reduction, a proper template of median filter is used to estimate the weld background. After the weld background is subtracted from the original image, an adaptite threshold segmentation algorithm is proposed to obtain the binary image, and then the morphological close and open operation, labeling algorithm and fids＇e alarm eliminating algorithm are applied to pracess the binary image to obtain the defect, ct detection result. At last, a fast realization procedure jbr proposed method is developed. The proposed method is tested in real-time X-ray image,s obtairted in different X-ray imaging sutems. Experiment results show that the proposed method is effective to detect low contrast weld dejects with few .false alarms and is adaptive to various types of real-time X-ray imaging systems.展开更多
X-ray detection and imaging via scintillators has been utilized in missions worldwide within areas of scientific research,medical industry,military defense and homeland security.Commercial scintillators are costly wit...X-ray detection and imaging via scintillators has been utilized in missions worldwide within areas of scientific research,medical industry,military defense and homeland security.Commercial scintillators are costly with high energy consumption through the sintering.It is of great significance to seek alternative scintillating materials for sensitive X-ray detection in the next-generation.Herein,eight structure-defined Ln(Ⅲ)-based metal-organic frameworks(Ln-MOFs)were prepared,2D[Ln_(2)(1,4-ndc)_(3)(DMF)_(4)]_(n)·nH_(2)O(Ln=Sm 1,Eu 2,Dy 3,Tb 4)and 3D[Ln_(4)(2,6-ndc)_(6)(μ_(2)H_(2)O)2(H_(2)O)_(4)]n·2nH_(2)O(Ln=Sm 5,Eu 6,Dy 7,Tb 8),where 1,4-H_(2)ndc=1,4-naphthalene dicarboxylate acid,2,6-H_(2)ndc=2,6-napthalene dicarboxylate acid,DMF=N,N-dimethylformamide.Merely compounds 2 and 6 show remarkable X-ray scintillation performance via the characteristic red emissions of Eu(Ⅲ)ions,in which the absorbed energy from the triplet states of the organic moieties can be transferred more efficiently to the resonance emission levels of Eu(Ⅲ)ions than other lanthanide(Ⅲ)ions.The X-ray dosage rate detection limits of 2 and 6 are superior to the standard for the medical X-ray diagnosis dosage rate.As proofs-of-concepts,matrix-mixed membranes fabricated with 2 and 6 have achieved remarkable X-ray imaging with high resolution for practical object shooting.展开更多
Fracture is one of the most common and unexpected traumas.If not treated in time,it may cause serious consequences such as joint stiffness,traumatic arthritis,and nerve injury.Using computer vision technology to detec...Fracture is one of the most common and unexpected traumas.If not treated in time,it may cause serious consequences such as joint stiffness,traumatic arthritis,and nerve injury.Using computer vision technology to detect fractures can reduce the workload and misdiagnosis of fractures and also improve the fracture detection speed.However,there are still some problems in sternum fracture detection,such as the low detection rate of small and occult fractures.In this work,the authors have constructed a dataset with 1227 labelled X-ray images for sternum fracture detection.The authors designed a fully automatic fracture detection model based on a deep convolution neural network(CNN).The authors used cascade R-CNN,attention mechanism,and atrous convolution to optimise the detection of small fractures in a large X-ray image with big local variations.The authors compared the detection results of YOLOv5 model,cascade R-CNN and other state-of-the-art models.The authors found that the convolution neural network based on cascade and attention mechanism models has a better detection effect and arrives at an mAP of 0.71,which is much better than using the YOLOv5 model(mAP=0.44)and cascade R-CNN(mAP=0.55).展开更多
文摘Aimed at the long and narrow geometric features and poor generalization ability of the damage detection in conveyor belts with steel rope cores using the X-ray image,a detection method of damage X-ray image is proposed based on the improved fully convolutional one-stage object detection(FCOS)algorithm.The regression performance of bounding boxes was optimized by introducing the complete intersection over union loss function into the improved algorithm.The feature fusion network structure is modified by adding adaptive fusion paths to the feature fusion network structure,which makes full use of the features of accurate localization and semantics of multi-scale feature fusion networks.Finally,the network structure was trained and validated by using the X-ray image dataset of damages in conveyor belts with steel rope cores provided by a flaw detection equipment manufacturer.In addition,the data enhancement methods such as rotating,mirroring,and scaling,were employed to enrich the image dataset so that the model is adequately trained.Experimental results showed that the improved FCOS algorithm promoted the precision rate and the recall rate by 20.9%and 14.8%respectively,compared with the original algorithm.Meanwhile,compared with Fast R-CNN,Faster R-CNN,SSD,and YOLOv3,the improved FCOS algorithm has obvious advantages;detection precision rate and recall rate of the modified network reached 95.8%and 97.0%respectively.Furthermore,it demonstrated a higher detection accuracy without affecting the speed.The results of this work have some reference significance for the automatic identification and detection of steel core conveyor belt damage.
基金supported by National Petroleum Major Project(Grant No.2011ZX05020-008)
文摘Fracture identification is important for the evaluation of carbonate reservoirs. However, conventional logging equipment has small depth of investigation and cannot detect rock fractures more than three meters away from the borehole. Remote acoustic logging uses phase-controlled array-transmitting and long sound probes that increase the depth of investigation. The interpretation of logging data with respect to fractures is typically guided by practical experience rather than theory and is often ambiguous. We use remote acoustic reflection logging data and high-order finite-difference approximations in the forward modeling and prestack reverse-time migration to image fractures. First, we perform forward modeling of the fracture responses as a function of the fracture-borehole wall distance, aperture, and dip angle. Second, we extract the energy intensity within the imaging area to determine whether the fracture can be identified as the formation velocity is varied. Finally, we evaluate the effect of the fracture-borehole distance, fracture aperture, and dip angle on fracture identification.
基金financial support from the National Natural Science Foundation of China(Nos.22075284,51872287,and U2030118)the Youth Innovation Promotion Association CAS(No.2019304)+1 种基金the Fund of Mindu Innovation Laboratory(No.2021ZR201)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20210039)
文摘Scintillation semiconductors play increasingly important medical diagnosis and industrial inspection roles.Recently,two-dimensional(2D)perovskites have been shown to be promising materials for medical X-ray imaging,but they are mostly used in low-energy(≤130 keV)regions.Direct detection of MeV X-rays,which ensure thorough penetration of the thick shell walls of containers,trucks,and aircraft,is also highly desired in practical industrial applications.Unfortunately,scintillation semiconductors for high-energy X-ray detection are currently scarce.Here,This paper reports a 2D(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single crystal with outstanding sensitivity and stability toward X-ray radiation that provides an ultra-wide detectable X-ray range of between 8.20 nGy_(air)s^(-1)(50 keV)and 15.24 mGy_(air)s^(-1)(9 MeV).The(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single-crystal detector with a vertical structure is used for high-performance X-ray imaging,delivering a good spatial resolution of 4.3 Ip mm^(-1)in a plane-scan imaging system.Low ionic migration in the 2D perovskite enables the vertical device to be operated with hundreds of keV to MeV X-ray radiation at high bias voltages,leading to a sensitivity of 46.90μC Gy_(air)-1 cm^(-2)(-1.16 Vμm^(-1))with 9 MeV X-ray radiation,demonstrating that 2D perovskites have enormous potential for high-energy industrial applications.
基金supported by the Outstanding Youth Fund of the National Natural Science Foundation of China(No.T2325020)the National Natural Science Foundation of China(Nos.62074136 and 52273307)the Natural Science Foundation of Zhejiang Province,China(No.LZ23F050005).
文摘X-ray andγ-ray detectors are widely used in medical,military,security,material analysis,and industrial inspection.In recent years,perovskite materials have become promising materials for radiation detection owing to their strong stopping power,considerable carrier transportation ability,and simple synthesis process.Previous studies have demonstrated both direct and indirect radiation detectors using perovskite materials.In this review,we aim to elucidate the mechanism by which X-rays andγ-rays interact with matter,explain the principles of the energy integrating mode and photon counting mode for direct detection,and discuss the key factors determining device performance.Furthermore,we summarize recent advances in perovskite-based radiation detectors for both modes.Additionally,we identify challenges that need to be overcome to enable perovskite materials to be successfully commercialized.
基金supported by the National Nature Science Foundation of China(NSFC)(U2241236,1220041913,52473253)the National Key Research and Development Program of China(2022ZDZX0007)+1 种基金Fundamental Research Open Subject Grant Program of Yantai Advanced Materials and Green Manufacturing Laboratory of Shandong Province(AMGM2024F15)Yunnan Major Scientific and Technological Projects(202402AB080011).
文摘The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites(MHPs)and their derivatives,which possess remarkable light yield and X-ray sensitivity.This comprehensive review delves into cutting-edge approaches for optimizing MHP scintillators performances by enhancing intrinsic physical properties and employing engineering radioluminescent(RL)light strategies,underscoring their potential for developing materials with superior high-resolution X-ray detection and imaging capabilities.We initially explore into recent research focused on strategies to effectively engineer the intrinsic physical properties of MHP scintillators,including light yield and response times.Additionally,we explore innovative engineering strategies involving stacked structures,waveguide effects,chiral circularly polarized luminescence,increased transparency,and the fabrication of flexile MHP scintillators,all of which effectively manage the RL light to achieve high-resolution and high-contrast X-ray imaging.Finally,we provide a roadmap for advancing next-generation MHP scintillators,highlighting their transformative potential in high-performance X-ray detection systems.
基金by the Guangdong Basic and Applied Basic Research Foundation under Grant 2021B1515120064.
文摘In real-world scenarios,dual-view X-ray machines have outnumbered single-view X-ray machines due to their ability to provide comprehensive internal information about the baggage,which is important for identifying prohibited items that are not visible in one view due to rotation or overlap.However,existing work still focuses mainly on single-view,and the limited dual-viewbasedwork only performs simple information fusion at the feature or decision level and lacks effective utilization of the complementary information hidden in dual view.To this end,this paper proposes an end-to-end dual-view prohibited item detection method,the core of which is an adaptive material-aware coordinate-aligned attention module(MACA)and an adaptive adjustment strategy(AAS).Specifically,we observe that in X-ray images,the material information of an object can be represented by color and texture features,and remains consistent across views,even under complex backgrounds.Therefore,our MACA first integrates the material information of the prohibited items in each view and then smoothly transfers these clearmaterial clues along the shared axis to the corresponding locations in the other view to enhance the feature representation of the blurred prohibited items in the other view.In addition,AAS can autonomously adjust the importance of the two views during feature learning to make joint optimizationmore stable and effective.Experiments on the DvXray dataset demonstrate that the proposed MACA and AAS can be plug-and-played into various detectors,such as Faster Region-based Convolutional Neural Network(Faster R-CNN)and Fully Convolutional One-Stage Object Detector(FCOS),and bring consistent performance gains.The entire framework performs favorably against state-of-the-art methods,especially on small-sized prohibited items,highlighting its potential application in reality.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(agreement No.075-15-2021-1349)。
文摘Synchrotron method of resonant X-ray reflectivity 2D mapping has been applied to study ultrathin epitaxial layers of WS_(2)grown by pulsed laser deposition on Al_(2)O_(3)(0001)substrates.The measurements were carried out across the L absorption edge of tungsten to perform depth-dependent element-selective analysis sensitive to potential chemical modification of the WS_(2)layer in ambient conditions.Despite the few monolayer thickness of the studied film,the experimentally measured maps of reflectance as a function of incident angle and photon energy turned out to be quite informative showing well-pronounced interference effects near W absorption edge at 10210 eV.The synchrotron studies were complemented with conventional non-resonant reflectance measurements carried out in the laboratory at a fixed photon energy corresponding to Cu Kαemission.The reconstruction of the depth and energy dependent scattering length density within the studied multilayers was carried out using the OpenCL empowered fitting software utilizing spectral shaping algorithm which does not rely on the pre-measured reference absorption spectra.A thin WO_(x) layer has been revealed at the surface of the WS_(2)layer pointing out to the effect of water assisted photo-oxidation reported in a number of works related to ultrathin layers of transition metal dichalcogenides.
基金financially supported by the National Natural Science Foundation of China(Nos.22175177,21971238,22193042,21833010,22125110,22122507,21921001,and U21A2069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(No.ZDBS-LY-SLH024)+1 种基金The National Postdoctoral Program for Innovative Talents(No.BX2021315)the National Key Research and Development Program of China(No.2019YFA0210402)。
文摘Lead-halide perovskites exhibit outstanding performance in X-ray detection due to their intrinsic features such as high charge carrier mobility,large atomic number,and long carrier lifetime,but the toxicity of lead is regarded as the major factor hindering their development.Here,we introduce organic molecule(R)-(-)-2-methylpiperazine(R-MPz)into the bismuth-based structure to synthesize lead-free(R)-(H_(2)MPz)BiI_(5)(R-MBI).The high-quality centimeter-sized single crystals have been obtained,which show a low dark current and superior environmental stability.Particularly,the single-crystal device of R-MBI exhibits a highμτproduct up to 1.88×10^(-4)cm^(2)/V and a low trap density of 1.21×10^(10)cm^(-3).Further,the detector displays excellent detection sensitivity of 263.58μC Gy_(air)^(-1)cm^(-2)and a favorable low detection limit of 4.35μGyair/s,both of which meet the requirement for medical diagnostics.These findings shed light on the exploration of innovative bismuth-based hybrid perovskites for high-performance X-ray detection.
基金financial support by the National Key Research and Development Program of Ministry of Science and Technology(No.2021YFB3801604)the National Natural Science Foundation(Nos.22073102,21827813,21921001)of China。
文摘Direct X-ray detectors,which directly convert X-rays into electrical signals through semiconductors,have higher space solution than scintillator-mediated indirect X-ray ones and are high desirable for early cancer detection and other applications,but the mainstream commercialα-Se detector is still largely limited by high production costs,large leakage current and low stability.This article reports an easily prepared,stable radiochromic semiconductive metal–organic framework(MOF),(MV)[Cd_(3)(tdc)_(4)]·2H_(2)O(RCS-1,H_(2)tdc=2,5-thiophenedicarboxylic acid;MV^(2+)=methyl viologen cation)with direct X-ray detecting ability.With a large bulk resistivity of 8.40×10^(9)Ωcm,this material ensures minimal dark current and low noise for X-ray detection.Additionally,it exhibits higher sensitivity to W KαX-rays(98.58μC Gy^(-1)cm^(-2))thanα-Se(~20μC Gy^(-1)cm^(-2)).Meanwhile,unlike most reported direct X-ray detecting semiconductors,compound RCS-1 shows remarkable color change upon X-ray irradiation owing to the presence of photochromism-active viologen cations.This feature offers an appealing visual detecting ability to direct X-ray detectors that provide only the electrical signals.
基金support from the National Natural Science Foundation of China(Nos.62205154 and 62205155)the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(Nos.NY221112 and NY222104)。
文摘X-ray detection plays a crucial role across various aspects of our daily lives,encompassing medical diagnoses,security screenings,and non-destructive examinations in industrial settings.Given the wide array of application contexts,a wealth of opportunities is entailed with the practical utilization of both organic and inorganic X-ray detection materials.A novel and promising contender in this realm is the emergence of metal-free organic halide perovskites(O-PVSKs),offering great opportunities and tremendous potential in X-ray detection.This potential can be attributed to the distinct crystalline configuration of O-PVSKs,where organic constituents are structured into an ABX3perovskite arrangement.Consequently,O-PVSKs exhibit captivating characteristics reminiscent of organic materials,such as lightweight nature and modifiability,all while retaining the distinctive traits associated with halide perovskites ranging from diverse structures to tunable optoelectronic properties.This review article delves into the intrinsic attributes of O-PVSKs and critically examines the viability of O-PVSKs in X-ray detection,through which key features that distinguish O-PVSKs from traditional organic semiconductors and perovskites are outlined.This is followed by a perspective given on their future avenues for exploration.
文摘Baggage screening is crucial for airport security. This paper examines various algorithms for firearm detection in X-ray images of baggage. The focus is on identifying steel barrel bores, which are essential for detonation. For this, the study uses a set of 22,000 X-ray scanned images. After preprocessing with filtering techniques to improve image quality, deep learning methods, such as Convolutional Neural Networks (CNNs), are applied for classification. The results are also compared with Autoencoder and Random Forest algorithms. The results are validated on a second dataset, highlighting the advantages of the adopted approach. Baggage screening is a very important part of the risk assessment and security screening process at airports. Automating the detection of dangerous objects from passenger baggage X-ray scanners can speed up and increase the efficiency of the entire security procedure.
基金National Science and Technology Major Project of China(No.2016ZX04003001)。
文摘A ceramic ball is a basic part widely used in precision bearings.There is no perfect testing equipment for ceramic ball surface defects at present.A fast visual detection algorithm for ceramic ball surface defects based on fringe reflection is designed.By means of image preprocessing,grayscale value accumulative differential positioning,edge detection,pixel-value row difference and template matching,the algorithm can locate feature points and judge whether the spherical surface has defects by the number of points.Taking black silicon nitride ceramic balls with a diameter of 6.35 mm as an example,the defect detection time for a single gray scale image is 0.78 s,and the detection limit is 16.5μm.
文摘Adhesion molecule CD146 (100-130kDa) belongs to the immunoglobulin super family and it is originally identified as a biomarker for melanoma. Recently, CD146 is found as
文摘Metal nano layer coating for increasing the sensitivity of spectroscopic measurements is proposed and experimentally demonstrated in this paper. The metal nano layer will attract the micro-poisons from any measured aqueous sample increasing the concentration of the micro-poison in the vicinity of the surface and significantly improves the sensitivity of the spectroscopic measurement. The demonstration was carried out using Fourier Transform Infra-Red (FTIR) operating in the MIR 400 cm-1 - 4000 cm-1 and 5 nm Gold layer which was grown on silicon oxide substrate. In the experimental demonstration Malathion organophosphate pesticide was used as micro-poison. The spectroscopic measurement proves that Malathion was attracted to the metal nano layer. Furthermore, the absorption lines of Malathion were detected and recognized. This proof of principle can be applied to any Internal Reflection Elements (IRE) and it can be used to purify any aqueous solutions and atmosphere from micro-poisons which will be attracted to the metal Nano layer.
文摘Halide perovskites have emerged as the next generation of optoelectronic materials and their remarkable performances have been attractive in the fields of solar cells,light-emitting diodes,photodetectors,etc.In addition,halide perovskites have been reported as an attractive new class of X-ray direct detecting materials recently,owning to the strong X-ray stopping capacity,excellent carrier transport,high sensitivity,and cost-effective manufacturing.Meanwhile,perovskite based direct Xray imagers have been successfully demonstrated as well.In this review article,we firstly introduced some fundamental principles of direct X-ray detection and imaging,and summarized the advances of perovskite materials for these purposes and finally put forward some needful and feasible directions.
基金supported by the National Natural Science Foundation of China(Grant nos.21773218,61974063)the Sichuan Province(Grant no.2018JY0206)the China Academy of Engineering Physics(Grant no.YZJJLX2018007)。
文摘Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.
基金supported by the National Natural Science Foundation of China(No.21775076)the fundamental research funds for central universities(China)
文摘A method for quantitative determination of fish sperm deoxyribonucleic acid(fsDNA)was developed by using titanium dioxide(TiO2)as an adsorbent and near-infrared diffuse reflectance spectroscopy(NIRDRS).The selective enrichment of fsDNA was proved by comparing the adsorption efficiency of bovine serum albumin,tyrosine and tryptophan,and the low adsorption background of TiO2 was illustrated by comparing the spectra of four commonly-used inorganic adsorbents(alkaline aluminium oxide,neutral aluminium oxide,nano-hydroxyapatite and silica).The spectral feature of fsDNA can be clearly observed in the spectrum of the sample.Partial least squares(PLS)model was built for quantitative determination of fsDNA using 28 solutions,and 13 solutions with interferences were used for validation of the model.The results showed that the correlation coefficient(R)between the predicted and the reference concentration is 0.9727 and the recoveries of the validation samples are in the range of 98.2%-100.7%.
文摘A first and effective method is proposed to detect weld deject adaptively in various Dypes of real-time X-ray images obtained in different conditions. After weld extraction and noise reduction, a proper template of median filter is used to estimate the weld background. After the weld background is subtracted from the original image, an adaptite threshold segmentation algorithm is proposed to obtain the binary image, and then the morphological close and open operation, labeling algorithm and fids＇e alarm eliminating algorithm are applied to pracess the binary image to obtain the defect, ct detection result. At last, a fast realization procedure jbr proposed method is developed. The proposed method is tested in real-time X-ray image,s obtairted in different X-ray imaging sutems. Experiment results show that the proposed method is effective to detect low contrast weld dejects with few .false alarms and is adaptive to various types of real-time X-ray imaging systems.
基金supported by the National Natural Science Foundation of China(Nos.21971240 and 21827813)the National Key R&D Program of China(No.2017YFA0206802)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000).
文摘X-ray detection and imaging via scintillators has been utilized in missions worldwide within areas of scientific research,medical industry,military defense and homeland security.Commercial scintillators are costly with high energy consumption through the sintering.It is of great significance to seek alternative scintillating materials for sensitive X-ray detection in the next-generation.Herein,eight structure-defined Ln(Ⅲ)-based metal-organic frameworks(Ln-MOFs)were prepared,2D[Ln_(2)(1,4-ndc)_(3)(DMF)_(4)]_(n)·nH_(2)O(Ln=Sm 1,Eu 2,Dy 3,Tb 4)and 3D[Ln_(4)(2,6-ndc)_(6)(μ_(2)H_(2)O)2(H_(2)O)_(4)]n·2nH_(2)O(Ln=Sm 5,Eu 6,Dy 7,Tb 8),where 1,4-H_(2)ndc=1,4-naphthalene dicarboxylate acid,2,6-H_(2)ndc=2,6-napthalene dicarboxylate acid,DMF=N,N-dimethylformamide.Merely compounds 2 and 6 show remarkable X-ray scintillation performance via the characteristic red emissions of Eu(Ⅲ)ions,in which the absorbed energy from the triplet states of the organic moieties can be transferred more efficiently to the resonance emission levels of Eu(Ⅲ)ions than other lanthanide(Ⅲ)ions.The X-ray dosage rate detection limits of 2 and 6 are superior to the standard for the medical X-ray diagnosis dosage rate.As proofs-of-concepts,matrix-mixed membranes fabricated with 2 and 6 have achieved remarkable X-ray imaging with high resolution for practical object shooting.
基金Science and technology plan project of Xi'an,Grant/Award Number:GXYD17.12Open Fund of Shaanxi Key Laboratory of Network Data Intelligent Processing,Grant/Award Number:XUPT-KLND(201802,201803)Key Research and Development Program of Shaanxi,Grant/Award Number:2019GY-021。
文摘Fracture is one of the most common and unexpected traumas.If not treated in time,it may cause serious consequences such as joint stiffness,traumatic arthritis,and nerve injury.Using computer vision technology to detect fractures can reduce the workload and misdiagnosis of fractures and also improve the fracture detection speed.However,there are still some problems in sternum fracture detection,such as the low detection rate of small and occult fractures.In this work,the authors have constructed a dataset with 1227 labelled X-ray images for sternum fracture detection.The authors designed a fully automatic fracture detection model based on a deep convolution neural network(CNN).The authors used cascade R-CNN,attention mechanism,and atrous convolution to optimise the detection of small fractures in a large X-ray image with big local variations.The authors compared the detection results of YOLOv5 model,cascade R-CNN and other state-of-the-art models.The authors found that the convolution neural network based on cascade and attention mechanism models has a better detection effect and arrives at an mAP of 0.71,which is much better than using the YOLOv5 model(mAP=0.44)and cascade R-CNN(mAP=0.55).
