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Study on direct point spread function measurement of capillary plate collimators with divergent X-ray beams

Radiation Detection Technology and Methods 2023年第3期7卷 321-336页

作者： Tianming Li Tao Luo YuPeng Xu Huilin He Liming Song Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of ScienceBeijing 100049China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China

Purpose The Filed of View(FOV)of eXTP/LAD is limited by lead-glass capillary plate collimators placed in front of the Silicon Drift Detectors(SDDs)for reducing the background contamination caused by the photons of Cosmic X-ray Background(CXB)leaking from outside the FOV.The core quality parameters of lead-glass capillary plate collimators are Open Area Ratio(OAR)and FOV.The performance of lead-glass capillary plate collimators is determined by its design specification such as pore-to-pore misalignment,pore perpendicularity with collimator surface and pore diameter.Since the design specification is the result of a large number of micropores,we use the full width at half maximum(FWHM)and peak value of point spread function(PSF)to characterize the capillary plate collimator performance.In order to quickly evaluate the performances of collimators,we developed a direct PSF measurement method using divergent beams.Methods In this paper,the simulation package of the divergent beamsmeasurement setup is developed based on Geant4.The simulation parameters of scintillator absorption length are corrected by experimental data.We simulate the PSF of collimators with different distribution of pore diameter and misalignment by parallel beams and divergent beams.By comparing the peak value and FWHM of collimators PSF,the feasibility in replacing parallel beams measurement with divergent beams measurement is studied.Results It is verified that the influence of the geometric size of 33μm radius of the micro-focus of X-ray tube can be ignored.The results show that the FWHM of collimators is increased with error root mean square error(RMS)of the distribution of collimators pore diameter and pore inclination angle.The peak value of PSF is mainly influenced by pore non-parallelism of the pores,and it decreases with an increase in pore inclination angle.Comparison of parallel beams PSF and divergent beams PSF shows well consistency of peak value and FWHM of collimator.But,the peak value of the divergent beams PSF is mainly affected by t

关键词： Geant4 EXTP/LAD Capillary plate collimators Divergent X-ray beams measurment

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An improved strategy for out-of-step oscillation separation devices based on apparent impedance angle applied to a series compensated line

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Protection and Control of Modern Power Systems 2022年第1期7卷 316-323页

作者： Haibo xu yupeng Cai Xiaolei Qu Zhiwei Dong NARI Group Corporation/State Grid Electric Power Research Institute Nanjing 210003China Electric Power Research Institute of State Grid Liaoning Electric Power Co. LtdShenyang 110006China

Out-of-step oscillation separation devices based on apparent impedance angle trajectory are widely used in the power grid in China,and their reliability is of great importance.In this paper,the influence mechanism of series compensation on apparent impedance angle trajectory is analyzed.It reveals that series compensation capacitors reduce the equivalent impedance angle and consequently the apparent impedance angle cannot pass through all four zones,resulting in the risk of failure for the separation devices.A revised method of apparent impedance angle based on compensation principle is discussed,and then an improved out-of-step oscillation detection criterion is proposed.In view of the fact that the apparent impedance angle at the moment of maximum current is equal to the equivalent impedance angle during an oscillation process,a practical algorithm based on the compensated apparent impedance angle is proposed.RTDS tests are conducted to verify the effectiveness of the new criterion,considering transmission lines with a high series compensation level.

关键词： Out-of-step oscillation separation Series compensated line Apparent impedance angle Compensated impedance angle

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Differential diagnosis of multiple primary lung cancers and intra-lung metastasis of lung cancer by multiple gene detection

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Chinese Medical Journal 2022年第1期135卷 86-88页

作者： Liuyang xu Jin Chen yupeng Zeng Xiao Li Zhihong Zhang Department of Pathology The First Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsu 210029China The Fourth Clinical Medical College of Nanjing Medical University NanjingJiangsu 210029China

A global trend towards greater health awareness with a resulting reduction in smoking has contributed to the improved control and early detection of lung cancer.[1]Furthermore,developments in diagnostic technologies have enhanced the detection of multifocal lung cancer,characterized by multiple cancerous lesions.Multifocal lung cancer can be divided into multiple primary lung cancer(MPLC)and pulmonary metastasis-associated lung cancer intrapulmonary metastases(IM)according to the types of lesions.The differential diagnosis of MPLC and IM is clinically important because of the direct impacts on tumor-node-metastasis staging and the implications for the treatment of lung cancer.The diagnostic criteria for MPLC were first proposed by Martini and Melamed in 1975[2]and were subsequently revised and supplemented by the American College of Chest Physicians(ACCP)in 2003.[3]These ACCP standards currently provide the main diagnostic criteria for the clinical differential diagnosis of MPLC and IM.MPLC and IM differ in terms of their clonal origins,which could provide a useful basis for multi-gene detection to assist the diagnosis of multifocal lung cancer.

关键词： diagnosis metastasis ACCP

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The failure propagation of weakly stable sediment:A reason for the formation of high-velocity turbidity currents in submarine canyons

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Journal of Oceanology and Limnology 2023年第1期41卷 100-117页

作者： yupeng REN Yi ZHANG Guohui xu Xingbei xu Houjie WANG Zhiyuan CHEN Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Qingdao 266100China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of Marine Environment and Ecology Ocean University of ChinaMinistry of EducationQingdao 266100China

The long-distance movement of turbidity currents in submarine canyons can transport large amounts of sediment to deep-sea plains.Previous studies show obvious differences in the turbidity current velocities derived from the multiple cables damage events ranging from 5.9 to 28.0 m/s and those of field observations between 0.15 and 7.2 m/s.Therefore,questions remain regarding whether a turbid fluid in an undersea environment can flow through a submarine canyon for a long distance at a high speed.A new model based on weakly stable sediment is proposed(proposed failure propagation model for weakly stable sediments,WS S-PFP model for short)to explain the high-speed and long-range motion of turbidity currents in submarine canyons through the combination of laboratory tests and numerical analogs.The model is based on two mechanisms:1)the original turbidity current triggers the destabilization of the weakly stable sediment bed and promotes the destabilization and transport of the soft sediment in the downstream direction and 2)the excitation wave that forms when the original turbidity current moves into the canyon leads to the destabilization and transport of the weakly stable sediment in the downstream direction.The proposed model will provide dynamic process interpretation for the study of deep-sea deposition,pollutant transport,and optical cable damage.

关键词： turbidity current excitation wave dense basal layer velocity WSS-PFP model

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Two Kinds of Waves Causing the Resuspension of Deep-Sea Sediments:Excitation and Internal Solitary Waves

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Journal of Ocean University of China 2023年第2期22卷 429-440页

作者： REN yupeng TIAN Hao CHEN Zhiyuan xu Guohui LIU Lejun LI Yibing Key Laboratory of Submarine Geosciences and Prospecting Techniques Ministry of EducationOcean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of Marine Environment and Ecology Ministry of EducationOcean University of ChinaQingdao 266100China First Institute of Oceanography MNRQingdao 266061China

The resuspension of marine sediments plays a key role in the biogeochemical cycle and marine ecology system.Internal solitary waves are considered to be important driving forces of the resuspension of bottom sediments.In this paper,the movement of turbidity currents,the generation and the effects on the bottom bed of internal solitary waves and excitation waves are studied by flume tests and numerical simulations,and the sediment resuspension are analyzed.The results show that the excitation wave can lead to the resuspension of the bottom sediments under all the conditions,while the internal solitary wave can lead to the resuspension of the sediment only under some special conditions,such as high amplitude or large underwater slope.Under the experimental conditions,the change in the near-bottom velocity caused by the excitation wave is close to three times that of the internal solitary wave.

关键词： deep-sea sediment resuspension internal solitary wave turbidity current excitation wave

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One-bit compressed sensing recovery algorithm robust to perturbation

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The Journal of China Universities of Posts and Telecommunications 2018年第1期25卷 62-69页

作者： Cui yupeng xu Wenbo Lin Jiaru Key Laboratory of Universal Wireless Communication Beijing University of Posts and Telecommunications

One-bit compressed sensing （CS） technology reconstructs the sparse signal when the available measurements are reduced to only their sign-bit. It is well known that CS reconstruction should know the measurement matrix exactly to obtain a correct result. However, the measurement matrix is probably perturbed in many practical scenarios. An iterative algorithm called perturbed binary iterative hard thresholding （PBIHT） is proposed to reconstruct the sparse signal from the binary measurements （sign measurements） where the measurement matrix experiences a general perturbation. The proposed algorithm can reconstruct the original data without any prior knowledge about the perturbation. Specifically, using the ideas of the gradient descent, PBIHT iteratively estimates signal and perturbation until the estimation converges. Simulation results demonstrate that, under certain conditions, PBIHT improves the performance of signal reconstruction in the perturbation scenario.

关键词： one-bit compressed sensing reconstruction algorlthm perturbation robust

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Integrated contra‑directionally coupled chirped Bragg grating waveguide with a linear group delay spectrum

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Frontiers of Optoelectronics 2023年第1期16卷 85-93页

作者： xudong Gao Zhenzhu xu yupeng Zhu Chengkun Yang Shoubao Han Zongming Duan Fan Zhang Jianji Dong Anhui Province Engineering Laboratory for Antennas and Microwave East China Research Institute of Electronic EngineeringHefei 230000China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Due to the advantages of low propagation loss,wide operation bandwidth,continuous delay tuning,fast tuning speed,and compact footprints,chirped Bragg grating waveguide has great application potential in wideband phased array beamforming systems.However,the disadvantage of large group delay error hinders their practical applications.The nonlinear group delay spectrum is one of the main factors causing large group delay errors.To solve this problem,waveguides with nonlinear gradient widths are adopted in this study to compensate for the nonlinear efect of the grating apodization on the mode efective index.As a result,a linear group delay spectrum is obtained in the experiment,and the group delay error is halved.

关键词： Bragg gratings Silicon photonics True time delay

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Rational construction of phosphate layer to optimize Cu-regulated Fe_(3)O_(4) as anode material with promoted energy storage performance for rechargeable Ni-Fe batteries

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Journal of Materials Science & Technology 2022年第13期108卷 133-141页

作者： Shuhua Hao yupeng Xing Peiyu Hou Gang Zhao Jinzhao Huang Shipeng Qiu Xijin xu Laboratory of Functional Micro and Nano Materials and Devices School of Physics and TechnologyUniversity of JinanJinan 250024China

Flexible aqueous energy storage devices with high security and flexibility are crucial for the progress of wearable energy storage.Particularly,aqueous rechargeable Ni-Fe batteries owning a large theoretical capacity,low cost and outstanding safety characteristics have emerged as a promising candidate for flexible aqueous energy storage devices.Herein,Cu-doped Fe_(3)O_(4)(CFO)with 3D coral structure was prepared by doping Cu^(2+) based on Fe_(3)O_(4)nanosheets(FO).Furthermore,the Fe-based anode material(CFPO)grown on carbon fibers was obtained by reconstructing the surface of CFO to form a low-crystallization shell which can enhance the ion transport.Excitingly,the newly developed CFPO electrode as an innovative anode material further exhibited a high capacity of 117.5 mAh g^(-1)(or 423 F g^(-1))at 1 A g^(-1).Then,the assembled aqueous Ni-Fe batteries with a high cell-voltage output of 1.6 V deliver a high capacity of 49.02 mAh g^(-1) at 1 A g^(-1) and retention ratio of 96.8%for capacitance after 10000 continuous cycles.What’s more,the aqueous quasi-solid-state batteries present a remarkable maximal energy density of 45.6 Wh kg^(-1) and a power density of 12 kW kg^(-1).This work provides an innovative and feasible way and optimization idea for the design of high-performance Fe-based anodes,and may promote the development of a new generation of flexible aqueous Ni-Fe batteries.

关键词： Ni-Fe batteries High voltage window regulation High energy and power density Anode materials Amorphous phosphate layer

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Impacts of Aggregation Methods and Trophospecies Number on the Structure and Function of Marine Food Webs

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Journal of Ocean University of China 2024年第1期23卷 190-198页

作者： LI Pengcheng ZHANG Chongliang xu Binduo JI yupeng LI Fan REN Yiping xuE Ying Laboratory of Fisheries Ecosystem Monitoring and Assessment College of FisheriesOcean University of ChinaQingdao 266003China Field Observation and Research Station of Haizhou Bay Fishery Ecosystem Ministry of EducationQingdao 266003China Shandong Marine Resources and Environment Research Institute Shandong Provincial Key Laboratory of Restoration for Marine EcologyYantai 264006China Laboratory for Marine Fisheries Science and Food Production Processes Laoshan LaboratoryQingdao 266237China

Aggregation of species with similar ecological properties is one of the effective methods to simplify food web researches.However,species aggregation will affect not only the complexity of modeling process but also the accuracy of models’outputs.Selection of aggregation methods and the number of trophospecies are the keys to study the simplification of food web.In this study,three aggregation methods,including taxonomic aggregation(TA),structural equivalence aggregation(SEA),and self-organizing maps(SOM),were analyzed and compared with the linear inverse model–Markov Chain Monte Carlo(LIM-MCMC)model.Impacts of aggregation methods and trophospecies number on food webs were evaluated based on the robustness and unitless of ecological net-work indices.Results showed that aggregation method of SEA performed better than the other two methods in estimating food web structure and function indices.The effects of aggregation methods were driven by the differences in species aggregation principles,which will alter food web structure and function through the redistribution of energy flow.According to the results of mean absolute percentage error(MAPE)which can be applied to evaluate the accuracy of the model,we found that MAPE in food web indices will increase with the reducing trophospecies number,and MAPE in food web function indices were smaller and more stable than those in food web structure indices.Therefore,trade-off between simplifying food webs and reflecting the status of ecosystem should be con-sidered in food web studies.These findings highlight the importance of aggregation methods and trophospecies number in the analy-sis of food web simplification.This study provided a framework to explore the extent to which food web models are affected by dif-ferent species aggregation,and will provide scientific basis for the construction of food webs.

关键词： LIM-MCMC model species aggregation trophospecies number aggregation methods food web indices

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Effect of particle composition and consolidation degree on the wave-induced liquefaction of soil beds

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Acta Oceanologica Sinica 2024年第2期43卷 11-22页

作者： Zhiyuan Chen yupeng Ren Guohui xu Meng Li Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Marine Ecological Restoration and Smart Ocean Engineering Research Center of Hebei Province Qinhuangdao 066000China Key Laboratory of Marine Environment and Ecology(Ocean University of China) Ministry of EducationQingdao 266100China Key Laboratory of Submarine Geoscience and Prospecting Techniques(Ocean University of China) Ministry of EducationQingdao 266100China

The wave-induced liquefaction of seabed is responsible for causing damage to marine structures.Particle composition and consolidation degree are the key factors affecting the pore water pressure response and liquefaction behavior of the seabed under wave action.The present study conducted wave flume experiments on silt and silty fine sand beds with varying particle compositions.Furthermore,a comprehensive analysis of the differences and underlying reasons for liquefaction behavior in two different types of soil was conducted from both macroscopic and microscopic perspectives.The experimental results indicate that the silt bed necessitates a lower wave load intensity to attain the liquefaction state in comparison to the silty fine sand bed.Additionally,the duration and development depth of liquefaction are greater in the silt bed.The dissimilarity in liquefaction behavior between the two types of soil can be attributed to the variation in their permeability and plastic deformation capacity.The permeability coefficient and compression modulus of silt are lower than those of silty fine sand.Consequently,silt is more prone to the accumulation of pore pressure and subsequent liquefaction under external loading.Prior research has demonstrated that silt beds with varying consolidation degrees exhibit distinct initial failure modes.Specifically,a dense bed undergoes shear failure,whereas a loose bed experiences initial liquefaction failure.This study utilized discrete element simulation to examine the microscopic mechanisms that underlie this phenomenon.

关键词： wave flume liquefaction pore water pressure consolidation permeability experiment discrete element simulation

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