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Model-driven CT reconstruction algorithm for nano-resolution x-ray phase contrast imaging

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Chinese Physics B 2024年第7期33卷 646-650页

作者：谭雨航蔡学宝杨杰成苏婷郑海荣梁栋朱佩平葛永帅 research Center for Medical Artificial Intelligence Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China institute of Electronic paper Displays South China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China Paul C Lauterbur research Center for Biomedical Imaging Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

The low-density imaging performance of a zone plate-based nano-resolution hard x-ray computed tomography(CT)system can be significantly improved by incorporating a grating-based Lau interferometer. Due to the diffraction, however,the acquired nano-resolution phase signal may suffer splitting problem, which impedes the direct reconstruction of phase contrast CT(nPCT) images. To overcome, a new model-driven nPCT image reconstruction algorithm is developed in this study. In it, the diffraction procedure is mathematically modeled into a matrix B, from which the projections without signal splitting can be generated invertedly. Furthermore, a penalized weighted least-square model with total variation(PWLSTV) is employed to denoise these projections, from which nPCT images with high accuracy are directly *** experiments demonstrate that this new algorithm is able to work with phase projections having any splitting distances. Moreover, results also reveal that nPCT images of higher signal-to-noise-ratio(SNR) could be reconstructed from projections having larger splitting distances. In summary, a novel model-driven nPCT image reconstruction algorithm with high accuracy and robustness is verified for the Lau interferometer-based hard x-ray nano-resolution phase contrast imaging.

关键词： splitting phase image reconstruction algorithm grating interferometer

Optimal search path planning of UUV in battlefeld ambush scene

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Defence Technology（防务技术） 2024年第2期32卷 541-552页

作者： Wei Feng Yan Ma Heng Li Haixiao Liu Xiangyao Meng Mo Zhou Naval research institute Beijing100161China

Aiming at the practical application of Unmanned Underwater Vehicle(UUV)in underwater combat,this paper proposes a battlefield ambush scene with UUV considering ocean ***,by establishing these mathematical models of ocean current environment,target movement,and sonar detection,the probability calculation methods of single UUV searching target and multiple UUV cooperatively searching target are given ***,based on the Hybrid Quantum-behaved Particle Swarm Optimization(HQPSO)algorithm,the path with the highest target search probability is ***,through simulation calculations,the influence of different UUV parameters and target parameters on the target search probability is analyzed,and the minimum number of UUVs that need to be deployed to complete the ambush task is demonstrated,and the optimal search path scheme is *** method proposed in this paper provides a theoretical basis for the practical application of UUV in the future combat.

关键词： Battlefield ambush Optimal search path planning UUV path Planning Probability of cooperative search

Intelligent responsive self-assembled micro-nanocapsules: Used to delay gel gelation time

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Petroleum Science 2024年第4期21卷 2433-2443页

作者： Chuan-Hong Kang Ji-Xiang Guo Dong-Tao Fei Wyclif Kiyingi Unconventional Petroleum research institute China University of Petroleum

In the application of polymer gels to profile control and water shutoff,the gelation time will directly determine whether the gel can "go further" in the formation,but the most of the methods for delaying gel gelation time are complicated or have low *** is an urgent need for an effective method for delaying gel gelation time with intelligent *** by the slow-release effect of drug capsules,this paper uses the self-assembly effect of gas-phase hydrophobic SiO2in aqueous solution as a capsule to prepare an intelligent responsive self-assembled *** capsule slowly releases the cross-linking agent under the stimulation of external conditions such as temperature and pH value,thus delaying gel gelation *** the pH value is 2 and the concentration of gas-phase hydrophobic SiO2particles is 10%,the gelation time of the capsule gel system at 30,60,90,and 120℃ is12.5,13.2,15.2,and 21.1 times longer than that of the gel system without containing capsule,*** with other methods,the yield stress of the gel without containing capsules was 78 Pa,and the yield stress after the addition of capsules was 322 *** intelligent responsive self-assembled micronanocapsules prepared by gas-phase hydrophobic silica nanoparticles can not only delay the gel gelation time,but also increase the gel *** slow release of cross-linking agent from capsule provides an effective method for prolongating the gelation time of polymer gels.

关键词： Profile control and water shutoff Polymer gel Delayed gelation time Intelligent response Self-assembled Micro-nanocapsules

Thermal stability improvement and microstructure optimization of high cobalt content Nd-Fe-B magnets via terbium grain boundary diffusion

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Journal of Rare Earths 2024年第8期42卷 1531-1538,I0004页

作者： Jiyuan Xu Ruiyang Meng Jing Liu Jiateng Zhang Rui Han Yikun Fang Shengzhi Dong Wei Li Division of Functional Materials research Central Iron and Steel Research InstituteBeijing100081China

The substitution of Fe by Co in the 2:14:1 phase is an effective method to increase the Curie temperature and enhance the thermal stability of the Nd-Fe-B ***,the accumulation of Co ele ment at the grain boundaries(GBs) changes the GBs from nonmagnetic to ferromagnetic and causes the thinlayer GBs to become rare,In this paper,the method of diffusing Tb element was chosen to improve the microstructure and temperature stability of high-Co *** original sintered Nd_(28.5)Dy_(3)-CO_(x)e_(bal)M_(0.6)B_(i)(x=0,6 wt%,12 wt%;M = Cu,Al,Zr) magnets with different Co contents were diffused with Tb by grain boundary diffusion(GBD).After GBD,high-Co magnets exhibit more continuously distributed thin-layer GBs,and their thermal stability is significantly *** high-Co magnets(x=6 wt%),the absolute value of the temperature coefficient of coercivity decreases from 0.603%/K to0.508%/K in the temperature range of 293-413 K,that of remanence decreases from 0.099%/K to 0.091%/K,and the coercivity increases from 18.44 to 25.04 *** electron microscopy(TEM)characterization reveals that there are both the 1:2 phase and the amorphous phase in the high-Co magnet before and after GBD,EDS elemental analysis shows that Tb element is more likely to preferentially replace the rare earth elements in the 2:14:1 main phase than in the 1:2 phase and the amorphous *** concentration of Tb at the edge of the main phase is much higher than that in the 1:2phase and amorphous phase,which is beneficial to the improvement of the *** preferential replacement of Tb elements at the edge of the 2:14:1 phase and thin-layer GBs with a more continuous distribution are synergistically responsible for improving the thermal stability of high-Co *** study indicates that GBD is an effective method to improve the microstructure and thermal stability of high-Co magnets.

关键词： Nd-Fe-B magnets Coercivity Grain boundary diffusion Thermal stability Micro structure Rare earths

Multi-UAVs Collaborative Path Planning in the Cramped Environment

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 529-538页

作者： Siyuan Feng Linzhi Zeng Jining Liu Yi Yang Wenjie Song School of Automation Beijing Institute of TechnologyNanjing 210039China Nanjing research institute of Electronics Technology Nanjing 210039China Yichang Testing Technique research institute Yichang 443003China IEEE

Due to its flexibility and complementarity, the multiUAVs system is well adapted to complex and cramped workspaces, with great application potential in the search and rescue(SAR) and indoor goods delivery fields. However, safe and effective path planning of multiple unmanned aerial vehicles(UAVs)in the cramped environment is always challenging: conflicts with each other are frequent because of high-density flight paths, collision probability increases because of space constraints, and the search space increases significantly, including time scale, 3D scale and model scale. Thus, this paper proposes a hierarchical collaborative planning framework with a conflict avoidance module at the high level and a path generation module at the low level. The enhanced conflict-base search(ECBS) in our framework is improved to handle the conflicts in the global path planning and avoid the occurrence of local deadlock. And both the collision and kinematic models of UAVs are considered to improve path smoothness and flight safety. Moreover, we specifically designed and published the cramped environment test set containing various unique obstacles to evaluating our framework performance thoroughly. Experiments are carried out relying on Rviz, with multiple flight missions: random, opposite, and staggered, which showed that the proposed method can generate smooth cooperative paths without conflict for at least 60 UAVs in a few *** benchmark and source code are released in https://***/inin-xingtian/multi-UAVs-path-planner.

关键词： Collision avoidance conflict resolution multi-unmanned aerial vehicles(UAVs)system path planning

Simple-structured hydrophilic sensors for sweat uric acid detection with laser-engraved polyimide electrodes and cellulose paper substrates

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Chinese Chemical Letters 2024年第3期35卷 443-448页

作者： Linhe Xu Xueshan Hu Shuang Zhou Ze Zhang Junxian Zhang Chao Li Daxian Zuo Hao Liu Gang Chen Jiayu Wan Jinsong Tao State Key Lab of Pulp and paper Engineering South China University of TechnologyGuangzhou 510640China Future Battery research Center Global Institute of Future TechnologyShanghai Jiao Tong UniversityShanghai 200240China

Accurate detection of uric acid(UA)is crucial for diagnosing gout,yet traditional sweat-based UA sensors continue to face challenges posed by complex and costly electrode fabrication methods,as well as weakly hydrophilic ***,we designed and developed simple,low-cost,and hydrophilic sweat UA detection sensors constructed by carbon electrodes and cellulose paper *** carbon electrodes were made by carbonized polyimide films through a simple,one-step laser engraving *** electrodes are porous,possess a large specific surface area,and are flexible and *** substrates were composed of highly hydrophilic cellulose paper that can effectively collect,store,and transport *** constructed electrodes demonstrate high sensitivity of 0.4μA Lμmol^(-1)cm^(-2),wide linear range of 2–100μmol/*** addition,our electrodes demonstrate high selectivity,excellent reproducibility,high flexibility,and outstanding stability against mechanical bending,temperature variations,and extended storage ***,our sensors have been proven to provide reliable results when detecting UA levels in real sweat and on real human *** envision that these sensors hold enormous potential for use in the prognosis,diagnosis,and treatment of gout.

关键词： Laser-engraved carbon Polyimide Cellulose paper Hydrophilicity Sweat uric acid

Functional Optical Fiber Sensors Detecting Imperceptible Physical/Chemical Changes for Smart Batteries

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Nano-Micro Letters 2024年第8期16卷 268-308页

作者： Yiding Li Li Wang Youzhi Song Wenwei Wang Cheng Lin Xiangming He institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084People’s Republic of China National Engineering research Center of Electric Vehicles Beijing Institute of Technology(BIT)Beijing 100081People’s Republic of China Shenzhen Automotive research institute of BIT(Shenzhen research institute of National Engineering research Center of Electric Vehicles) Shenzhen 518118People’s Republic of China

The battery technology progress has been a contradictory process in which performance improvement and hidden risks *** the battery is still a“black box”,thus requiring a deep understanding of its internal *** battery should“sense its internal physical/chemical conditions”,which puts strict requirements on embedded sensing *** paper summarizes the application of advanced optical fiber sensors in lithium-ion batteries and energy storage technologies that may be mass deployed,focuses on the insights of advanced optical fiber sensors into the processes of one-dimensional nano-micro-level battery material structural phase transition,electrolyte degradation,electrode-electrolyte interface dynamics to three-dimensional macro-safety *** paper contributes to understanding how to use optical fiber sensors to achieve“real”and“embedded”*** the inherent advantages of the advanced optical fiber sensor,it helps clarify the battery internal state and reaction mechanism,aiding in the establishment of more detailed *** advancements can promote the development of smart batteries,with significant importance lying in essentially promoting the improvement of system ***,with the help of smart batteries in the future,the importance of consistency can be weakened or even *** application of advanced optical fiber sensors helps comprehensively improve the battery quality,reliability,and life.

关键词： Smart battery Advanced embedded optical fiber sensor Battery internal physical/chemical state Quality-reliability-life characteristic

Mode Multiplication of Cylindrical Vector Beam Using Raytracing Control

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Chinese Physics Letters 2024年第9期41卷 40-51页

作者： Jing Wang Qingji Zeng Haisheng Wu Chuangxin Xie Huapeng Ye Ze Dong Dianyuan Fan Shuqing Chen institute of Microscale Optoelectronics Shenzhen UniversityShenzhen 518060China Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper DisplaysSouth China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China

Cylindrical vector beams(CVBs)hold significant promise in mode division multiplexing communication owing to their inherent vector mode ***,existing studies for facilitating CVB channel processing are confined to mode shift conversions due to their reliance on spin-dependent helical modulations,overlooking the pursuit of mode multiplication *** challenge lies in the multiplicative operation upon inhomogeneous vector mode manipulation,which is expected to advance versatile CVB channel switching and ***,we tackle this gap by introducing a raytracing control strategy that conformally maps the light rays of CVB from the whole annulus distribution to an annular sector *** with the multifold conformal annulus-sector mappings and polarization-insensitive phase modulations,this approach facilitates the parallel transformation of input CVB into multiple complementary components,enabling the mode multiplication conversion with protected vector *** as a demonstration,we experimentally implemented the multiplicative operation of four CVB modes with the multiplier factors of𝑁N=+2 and N=−3,achieving the converted mode purities over 94.24%and 88.37%.Subsequently,200 Gbit/s quadrature phase shift keying signals were successfully transmitted upon multiplicative switching of four CVB channels,with the bit-error-rate approaching 1×10−*** results underscore our strategy’s efficacy in CVB mode multiplication,which may open promising prospects for its advanced applications.

关键词： structure. multiplicative approaching

Distributed Application Addressing in 6G Network

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China Communications 2024年第4期21卷 193-207页

作者： Liu Jie Chen Sibo Liu Yuqin Mo Zhiwei Lin Yilin Zhu Hongmei He Yufeng China Telecom research institute Guangzhou 510632China

To ensure the extreme performances of the new 6G services,applications will be deployed at deep edge,resulting in a serious challenge of distributed application *** paper traces back the latest development of mobile network application addressing,analyzes two novel addressing methods in carrier network,and puts forward a 6G endogenous application addressing scheme by integrating some of their essence into the 6G network architecture,combining the new 6G capabilities of computing&network convergence,endogenous intelligence,and communication-sensing *** paper further illustrates how that the proposed method works in 6G networks and gives preliminary experimental verification.

关键词： application addressing CNC(Computing&Network Convergence) DNS(Domain Name System) ICN(Information-Centric Network) 6G