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Enhancing light yield of Tb^(3+)-doped fluoride nanoscintillator with restricted positive hysteresis for low-dose High-resolution X-ray imaging

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Nano Research 2023年第2期16卷 3339-3347页

作者： Yi Cheng Lei Lei Wenjuan Zhu Yubin Wang Hai Guo Shiqing Xu Key Laboratory of Rare Earth Optoelectronic Materials and Devices of Zhejiang Province Institute of Optoelectronic Materials and DevicesChina Jiliang UniversityHangzhou 310018China College of Electronic and Optical Engineering and College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China Department of Physics Zhejiang Normal UniversityJinhua 321004China

Developing scintillators with high light yield(LY),superior irradiation stability,and weak afterglow is of significance for the realization of low-dose High-resolution X-ray excited optical luminescence(XEOL)imaging.Lanthanide doped fluoride nanoparticles possess low toxicity,superior environmental stability,facial fabrication process,and tunable emissions,which are appropriate candidates for the next generation nanoscintillators(NSs).However,the low LY and strong positive hysteresis greatly restrict their practical application.Here,we propose an effective strategy that engineers energy gap to significantly enhance the LY.Our results verify that the tetragonal LiLuF4 host benefits the crystal level splitting of Tb^(3+)ions,which greatly promotes the electrons population on the Tb^(3+):5D4 level followed by the enhanced LY.The LY of LiLuF4:Tb@LiLuF4 NSs is calculated to be~31,169 photons/MeV,which is much higher than the lead halide perovskite colloidal CsPbBr3(~21,000 photons/MeV)and LuAG:Ce(~22,000 photons/MeV)scintillators.Moreover,the positive hysteresis is remarkably restricted after coating a thin shell.The X-ray detection limit and spatial resolution are measured to be~21.27 nGy/s and~7.2 lp/mm,respectively.We further verify that this core/shell NS can be employed as scintillating screen to realize XEOL imaging under the low dose rate of 13.86μGy/s.Our results provide an effective route to develop high performance NSs,which will promote great opportunities for the development of low-dose High-resolution XEOL imaging devices.

关键词： nanoscintillators X-ray excited optical luminescence(XEOL)imaging crystal level splitting low-dose High-resolution

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Verification and Validation of High-resolution Inviscid and Viscous Conical Nozzle Flows

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Communications on Applied Mathematics and Computation 2024年第1期6卷 533-549页

作者： Luciano K.Araki Rafael B.de R.Borges Nicholas Dicati P.da Silva Chi-Wang Shu Department of Mechanical Engineering Federal University of ParanáCuritiba81531-980ParanáBrazil Mathematics and Statistics Institute Rio de Janeiro State UniversityRio de Janeiro20550-900Rio de JaneiroBrazil Department of Mechanical Engineering State University of MaringáMaringá87020-900ParanáBrazil Division of Applied Mathematics Brown UniversityProvidenceRI02912USA

Capturing elaborated flow structures and phenomena is required for well-solved numerical flows.The finite difference methods allow simple discretization of mesh and model equations.However,they need simpler meshes,e.g.,rectangular.The inverse Lax-Wendroff(ILW)procedure can handle complex geometries for rectangular meshes.High-resolution and high-order methods can capture elaborated flow structures and phenomena.They also have strong mathematical and physical backgrounds,such as positivity-preserving,jump conditions,and wave propagation concepts.We perceive an effort toward direct numerical simulation,for instance,regarding weighted essentially non-oscillatory(WENO)schemes.Thus,we propose to solve a challenging engineering application without turbulence models.We aim to verify and validate recent High-resolution and high-order methods.To check the solver accuracy,we solved vortex and Couette flows.Then,we solved inviscid and viscous nozzle flows for a conical profile.We employed the finite difference method,positivity-preserving Lax-Friedrichs splitting,High-resolution viscous terms discretization,fifth-order multi-resolution WENO,ILW,and third-order strong stability preserving Runge-Kutta.We showed the solver is high-order and captured elaborated flow structures and phenomena.One can see oblique shocks in both nozzle flows.In the viscous flow,we also captured a free-shock separation,recirculation,entrainment region,Mach disk,and the diamond-shaped pattern of nozzle flows.

关键词： High-resolution Compressible Navier-Stokes Free-shock separation Nozzle flow

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Radially Symmetrical Problems for Compressible Fluids with a High-resolution Boundary Condition

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Advances in Applied Mathematics and Mechanics 2023年第2期15卷 428-449页

作者： Zijin Zhu Xiaoyan Hu Guoxi Ni Institute of Applied Physics and Computational Mathematics BeijingChina Graduate School of China Academy of Engineering Physics BeijingChina

Imposing appropriate numerical boundary conditions at the symmetrical center r=0 is vital when computing compressible fluids with radial symmetry.Extrapolation and other traditional techniques are often employed,but spurious numerical oscillations or wall-heating phenomena can occur.In this paper,we emphasize that because of the conservation property,the updating formula of the boundary cell average can coincide with the one for interior cell averages.To achieve second-order accuracy both in time and space,we associate obtaining the inner boundary value at r=0 with the resolution of the corresponding one-sided generalized Riemann problem(GRP).Acoustic approximation is applied in this process.It creates conditions to avoid the singularity of type 1/r and aids in obtaining the value of the singular quantity using L’Hospital’s rule.Several challenging scenarios are tested to demonstrate the effectiveness and robustness of our approach.

关键词： Radially symmetrical High-resolution conservation singularity numerical boundary condition GRP acoustic approximation

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High-resolution, full-color quantum dot light-emitting diode display fabricated via photolithography approach

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Nano Research 2020年第9期13卷 2485-2491页

作者： Wenhai Mei Zhenqi Zhang Aidi Zhang Dong Li Xiaoyuan Zhang Haowei Wang Zhuo Chen Yanzhao Li Xinguo Li Xiaoguang Xu BOE Technology Group Co. Ltd.Beijing 100176China School of Software&Microelectronics Department Peking UniversityBeijing 102600China

Displays play an extremely important role in modern information society,which creates a never-ending demand for the new and better products and technologies.The latest requirements for novel display technologies focus on high resolution and high color gamut.Among emerging technologies that include organic light-emitting diode(OL ED),micro light-emiting diode(micro-LED),quantum dot light-emitting diode(QLED),laser display,holographic display and others,QLED is promising owing to its intrinsic high color gamut and the possibility to achieve high resolution with photolithography approach.However,previously demonstrated photolthography techniques suffer from reduced device performance and color Impurities in subpixels from the process.In this study,we demonstrated a sacrificial layer assisted patterming(SLAP)approach,which can be applied in conjunction with photolithography to fabricate High-resolution,full-colo quantum dot(QD)patterns.In this approach,the negative photoresist(PR)and sacrificial layer(SL)were uilized to determine the pixels for QD deposition,while at the same time the SL helps protect the QD layer and keep it intact(named PR-SL approach).To prove this method's viability for QLED display manufacture,a 500-ppi,full-color passive matrix(PM)-QLED prototype was fabricated via this process.Results show that there were no color impurities in the subpixels,and the PM-QL ED has a high color gamut of 114%National Television Standards Committee(NTSC).To the best of our knowledge,this is the first ull-olor QLED prototype with such a high resolution.We anticipate that this innovative patteming technique will open a new horizon for future display technologies and may lead to a disruptive and innovative change in display industry.

关键词： quantum dots sacrificial layer assisted patterning quantum dot light-emitting diodes photolithography High-resolution

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Donor-conformation-dependent energy transfer for dual-color fluorescent probe with High-resolution imaging

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Science China Chemistry 2021年第8期64卷 1310-1315页

作者： Lifang Guo Xin Jin Hao Liu Jiangnan Zhu Zhiyun Zhang Jianhua Su Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research CentreFrontiers Science Center for Materiobiology and Dynamic ChemistryEast China University of Science&TechnologyShanghai200237China

Herein,we presented a brand-new concept to construct the Forster resonance energy transfer(FRET)based cassette by integrating a vibration-induced emission(VIE)chromophore as the donor.Different from traditional donors only with a single emission,the VIE donor possessed well-separated dual emission bands by altering the excited state molecular configuration from the bent state to the planar state.By linking an acceptor such as a cyanine dye(Cy5),a novel VIE-FRET cassette(PPCy5)was prepared.The planar emission profile of the VIE donor moiety could fully cover the absorption of Cy5,and thus the complete FRET process enabled the excellent bimodal spectra difference of 142 nm and ultra-large pseudo-Stokes shift of up to 300 nm.Benefiting from the viscosity-dependent characteristic of the VIE donor,PPCy5 could clearly and intuitively reveal the different viscosity regions in vivo by dual-color and High-resolution imaging.The VIE-FRET paradigm provides an optional platform for developing donor-acceptor-based dual-color fluorescent probes with High-resolution imaging ability.

关键词： VIE FRET High-resolution dual-color large Stokes shift

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Advances in urban information extraction from High-resolution remote sensing imagery

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Science China Earth Sciences 2020年第4期63卷 463-475页

作者： Jianya GONG Chun LIU Xin HUANG School of Remote Sensing and Information Engineering Wuhan UniversityWuhan 430079China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China

The study of urban area is one of the hottest research topics in the field of remote sensing. With the accumulation of High-resolution(HR) remote sensing data and emerging of new satellite sensors, HR observation of urban areas has become increasingly possible, which provides us with more elaborate urban information. However, the strong heterogeneity in the spectral and spatial domain of HR imagery brings great challenges to urban remote sensing. In recent years, numerous approaches were proposed to deal with HR image interpretation over complex urban scenes, including a series of features from low level to high level, as well as state-of-the-art methods depicting not only the urban extent, but also the intra-urban variations. In this paper, we aim to summarize the major advances in HR urban remote sensing from the aspects of feature representation and information extraction. Moreover, the future trends are discussed from the perspectives of methodology, urban structure and pattern characterization, big data challenge, and global mapping.

关键词： High-resolution Urban remote sensing Feature extraction Land use/land cover classification Change detection

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Research on monopulse forward-looking High-resolution imaging algorithm based on adaptive iteration

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Defence Technology（防务技术） 2020年第1期16卷 158-171页

作者： Cheng Cheng Xiao-dong Zhou Min Gao Zhu-lin Zong Yong-xiang Ji Bo Yu Department of Missile Engineering Army Engineering UniversityNo.97 Westroad HepingShijiazhuangChina Department of Ammunition Engineering Army Engineering UniversityNo.97 Westroad HepingShijiazhuangChina Research Institute of Electronic Science and Technology University of Electronic Science and TechnologyNo.4Section 2Jianbei RoadChengduChina China Huayin Weapon Test Center No.450 Yuemiao StreetHuayinShaanxiChina North Automatic Control Technology Institute No.351 Tiyu RoadTaiyuanChina

In this paper,we proposed a monopulse forward-looking High-resolution imaging algorithm based on adaptive iteration for missile-borne detector.Through iteration,the proposed algorithm automatically selects the echo signal of isolated strong-scattering points from the receiving echo signal data to accurately estimate the actual optimal monopulse response curve(MRC) of the same distance range,and we applied optimal MRC to realize the azimuth self-focusing in the process of imaging.We use real-time echo data to perform error correction for obtaining the optimal MRC,and the azimuth angulation accuracy may reach the optimum at a certain distance dimension.We experimentally demonstrate the validity,reliability and high performance of the proposed algorithm.The azimuth angulation accuracy may reach up to ten times of the detection beam-width.The simulation experiments have verified the feasibility of this strategy,with the average height measurement error being 7.8%.In the out-field unmanned aerial vehicle(UAV) tests,the height measurement error is less than 25 m,and the whole response time can satisfy the requirements of a missile-borne detector.

关键词： Monopulse imaging High-resolution Adaptive iteration Missile-borne detector

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Temperature-sensitive polymeric nanogels encapsulating withβ-cyclodextrin and ICG complex for High-resolution deep-tissue ultrasound-switchable fluorescence imaging

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Nano Research 2020年第4期13卷 1100-1110页

作者： Ruilin Liu Tingfeng Yao Yang Liu Shuai Yu Liqin Ren Yi Hong Kytai T.Nguyen Baohong Yuan Ultrasound and Optical Imaging Laboratory Department of Bioengineeringthe University of Texas at ArlingtonArlingtonTX 76019USA Joint Biomedical Engineering Program the University of Texas at Arlington and the University of Texas Southwestern Medical CenterDallasTX 75390USA Department of Bioengineering the University of Texas at ArlingtonArlingtonTX 76019USA

One of the thorny problems currently impeding the applications of the fluorescence imaging technique is the poor spatial resolution in deep tissue.Ultrasound-switchable fluorescence(USF)imaging is a novel imaging tool that has recently been explored to possibly surmount the above-mentioned bottleneck.Herein,αβ-cyclodextrin/indocyanine green(ICG)complex-encapsulated poly(N-isopropylacrylamide)(PNIPAM)nanogel was synthesized and studied for ex vivo/in vivo deep tissue/High-resolution near infrared USF(NIR-USF)imaging.To be specific,our results revealed that the average diameter of the as-prepared nanogels was significantly decreased to-32 nm from-335 nm compared to the reported ICG-PNIPAM nanoparticles.Additionally,the excitation/emission characteristics of the ICG itself in present nanogels were almost completely retained,and the resultant nanogel exhibited high physiological stability and positive biocompatibility.In particular,the signal-to-noise ratio of the USF image for the PNIPAM/P-cyclodextrin/ICG nanogel(33.01±2.42 dB)was prominently higher than that of the ICG-PNIPAM nanoparticles(18.73±0.33 dB)in 1.5-cm-thick chicken breast tissues.The NIR-USF imaging in 3.5-cm-thick chicken breast tissues was achieved using this new probe.The e x v iv o NIR-USF imaging of the mouse liver was also successfully obtained.Animal experiments showed that the present nanogels were able to be effectively accumulated into U87 tumor-bearing mice via enhanced permeability and retention effects,and the High-resolution NIR-USF imaging of in v ivo tumor was efficiently acquired.The metabolism and in vivo biodistribution of the nanogels were evaluated.Overall,the results suggest that the current nanogel is a highly promising NIR-USF probe for deep tissue and High-resolution USF imaging.

关键词： deep tissue imaging High-resolution ultrasound-switchable NIR fluorescence imaging in vivo imaging

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High-resolution forward-looking imaging algorithm for missile-borne detectors

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Journal of Systems Engineering and Electronics 2019年第3期30卷 456-466页

作者： CHENG Cheng GAO Min ZHOU Xiaodong Department of Missile Engineering Army Engineering University Shijiazhuang 050003 China Department of Ammunition Engineering Army Engineering University Shijiazhuang 050003 China

Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive High-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missile-borne detector in the target regions;thereby the azimuth angulation accuracy at the same distance dimension is improved dynamically. Thus, azimuth information of the targets in the detection area may be obtained accurately. The proposed imaging algorithm breaks through the conventional misconception of merely using azimuth discrimination curves under ideal conditions during monopulse angulation. The real-time echo data from the target region are used to perform error correction for this discrimination curve, and finally the accuracy of the azimuth angulation may reach the optimum at the same distance dimension. A series of experiments demonstrate the validity, reliability and high performance of the proposed imaging algorithm. Azimuth angulation accuracy may reach ten times that of the detection beam width. Meanwhile, the running time of this algorithm satisfies the requirements of missile-borne platforms.

关键词： forward-looking imaging High-resolution missileborne detector self-adaptive radio proximity fuze

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Distal esophageal spasm:Update on diagnosis and management in the era of High-resolution manometry

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World Journal of Clinical Cases 2020年第6期8卷 1026-1032页

作者： Harika Gorti Salih Samo Nikrad Shahnavaz Emad Qayed Department of Medicine Atlanta Veteran Affairs Medical Center and Emory University School of MedicineAtlantaGA 30322United States Department of Medicine Division of Digestive DiseasesEmory University School of MedicineAtlantaGA 30303United States

Distal esophageal spasm(DES)is a rare major motility disorder in the Chicago classification of esophageal motility disorders(CC).DES is diagnosed by finding of≥20%premature contractions,with normal lower esophageal sphincter(LES)relaxation on High-resolution manometry(HRM)in the latest version of CCv3.0.This feature differentiates it from achalasia type 3,which has an elevated LES relaxation pressure.Like other spastic esophageal disorders,DES has been linked to conditions such as gastroesophageal reflux disease,psychiatric conditions,and narcotic use.In addition to HRM,ancillary tests such as endoscopy and barium esophagram can provide supplemental information to differentiate DES from other conditions.Functional lumen imaging probe(FLIP),a new cutting-edge diagnostic tool,is able to recognize abnormal LES dysfunction that can be missed by HRM and can further guide LES targeted treatment when esophagogastric junction outflow obstruction is diagnosed on FLIP.Medical treatment in DES mostly targets symptomatic relief and often fails.Botulinum toxin injection during endoscopy may provide a temporary therapy that wears off over time.Myotomy through peroral endoscopic myotomy or via surgical Heller myotomy can provide long term relief in cases with persistent symptoms.

关键词： Distal esophageal spasm High-resolution manometry Esophagus Functional lumenal imaging probe Spastic achalasia Esophageal motility

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