2024

• Record 181 of
  
  Title:Multilevel Attention Unet Segmentation Algorithm for Lung Cancer Based on CT Images
  
  Author(s):Wang, Huan; Qiu, Shi; Zhang, Benyue; Xiao, Lixuan
  Source: CMC-COMPUTERS MATERIALS & CONTINUA  Volume: 78  Issue: 2  DOI: 10.32604/cmc.2023.046821  Published: 2024  
  Abstract:Lung cancer is a malady of the lungs that gravely jeopardizes human health. Therefore, early detection and treatment are paramount for the preservation of human life. Lung computed tomography (CT) image sequences can explicitly delineate the pathological condition of the lungs. To meet the imperative for accurate diagnosis by physicians, expeditious segmentation of the region harboring lung cancer is of utmost significance. We utilize computeraided methods to emulate the diagnostic process in which physicians concentrate on lung cancer in a sequential manner, erect an interpretable model, and attain segmentation of lung cancer. The specific advancements can be encapsulated as follows: 1) Concentration on the lung parenchyma region: Based on 16 -bit CT image capturing and the luminance characteristics of lung cancer, we proffer an intercept histogram algorithm. 2) Focus on the specific locus of lung malignancy: Utilizing the spatial interrelation of lung cancer, we propose a memory -based Unet architecture and incorporate skip connections. 3) Data Imbalance: In accordance with the prevalent situation of an overabundance of negative samples and a paucity of positive samples, we scrutinize the existing loss function and suggest a mixed loss function. Experimental results with pre-existing publicly available datasets and assembled datasets demonstrate that the segmentation efficacy, measured as Area Overlap Measure (AOM) is superior to 0.81, which markedly ameliorates in comparison with conventional algorithms, thereby facilitating physicians in diagnosis.
  Accession Number:
  ISSN: 1546-2218
  eISSN: 1546-2226
• Record 182 of
  
  Title:A Three-State Space Modeling Method for Aircraft System Reliability Design
  
  Author(s):Wang, Yao; Wang, Fengtao; Feng, Yue; Cao, Shancheng
  Source: MACHINES  Volume: 12  Issue: 1  DOI: 10.3390/machines12010013  Published: 2024  
  Abstract:Reliability is an inherent attribute of a system through optimal system design. However, during the aircraft system development process, the reliability evaluation and system function design efforts are often disconnected, leading to a divide between reliability experts and system designers in their work schedule. This disconnect results in an inefficient aircraft system reliability optimization process, known as the two-skin phenomenon. To address this issue, a three-state space model is proposed. Firstly, an analysis was conducted on the relationship between the system function architecture developed by the system designers and the reliability evaluation performed by the reliability experts. Secondly, based on the principle of function flow, the state of failure was categorized into physical failure and non-physical failure. Additionally, a new state of function loss was introduced as the third state for the system, in addition to the traditional states of normal and faulty. Thirdly, through the state of Function loss, an effective integration of system fault modes and function modes was achieved, leading to an optimized system reliability model. A three-state space modeling method was then developed by transforming the system function architecture into a system reliability model. Finally, this new model was applied to an aircraft's rudder and fly-by-wire control system. The results demonstrate that the function architecture at the design stage of the system can be accurately transformed into the new three-state space model. The structure aligns closely with the function architecture and can be effectively utilized in quantitative system reliability calculations. In this way, the process of ensuring system reliability can be seamlessly integrated into the system optimization design process. This integration alleviates the issue of disjointed work between reliability experts and system designers, leading to a more streamlined and efficient aircraft system optimization process.
  Accession Number: 13
  ISSN:
  eISSN: 2075-1702
• Record 183 of
  
  Title:An Iterative High-Precision Algorithm for Multi-Beam Array Stitching Method Based on Scanning Hartmann
  
  Author(s):Yan, Xiangyu; Li, Dahai; Kewei, E.; Feng, Fang; Wang, Tao; Xue, Xun; Zhang, Zekun; Lu, Kai
  Source: APPLIED SCIENCES-BASEL  Volume: 14  Issue: 2  DOI: 10.3390/app14020794  Published: 2024  
  Abstract:The multi-beam array stitching test system (MASTS) based on the Hartmann principle is employed to measure the aberrations in large-aperture optical systems. As each small-aperture and ideal parallel beam traverses the optical system, it is converged into a spot at the focal plane of the optical system. The centroid position of the spot contains the information about the wavefront slope of the sub-aperture at that specific location in the optical system. Scanning the optical system with this small-aperture beam across the entire aperture of the optical system, we can yield the aberration information to be tested. To mitigate pointing errors induced by scanning motion and accurately obtain the aberration signals of the optical system, nine beams are integrated into a 3 x 3 multi-beam array system, and their directions are aligned to be identical. However, achieving complete alignment in the same direction for all nine beams is a challenging task, resulting in errors due to their pointing differences within the array. This paper introduces an iterative algorithm designed to obtain high-precision multi-beam pointing errors and to reconstruct the wavefront of the optical system under test. This enables a more accurate measurement of wavefront aberrations in the optical system to be tested. Firstly, simulation models were implemented to validate the algorithm's feasibility. Additionally, a scanning optical measurement system with a multi-beam array was developed in our lab, and the iterative algorithm was applied to process our experimental data. The results were then compared with interferometer data, demonstrating that our algorithm is feasible for MASTS to measure aberrations in large-aperture optical systems with high accuracy.
  Accession Number: 794
  ISSN:
  eISSN: 2076-3417
• Record 184 of
  
  Title:Electron vortices generation of photoelectron of H2+ by counter-rotating circularly polarized attosecond pulses
  
  Author(s):Yang, Haojing; Liu, Xiaoyu; Zhu, Fengzheng; Jiao, Liguang; Liu, Aihua
  Source: CHINESE PHYSICS B  Volume: 33  Issue: 1  DOI: 10.1088/1674-1056/ad011a  Published: 2024  
  Abstract:Molecular-frame photoelectron momentum distributions (MF-PMDs) of an H-2(+) molecule ion in the presence of a pair of counter-rotating circularly polarized attosecond extreme ultraviolet laser pulses is studied by numerically solving the two-dimensional time-dependent Schrodinger equation within the frozen-nuclei approximation. At small time delay, our simulations show that the electron vortex structure is sensitive to the time delay and relative phase between the counter-rotating pulses when they are partially overlapped. By adjusting time delay and relative phase, we have the ability to manipulate the MF-PMDs and the appearance of spiral arms. We further show that the internuclear distance can affect the spiral vortices due to its different transition cross sections in the parallel and perpendicular geometries. The lowest-order perturbation theory is employed to interpret these phenomena qualitatively. It is concluded that the internuclear distance-dependent transition cross sections and the confinement effect in diatomic molecules are responsible for the variation of vortex structures in the MF-PMDs.
  Accession Number: 13303
  ISSN: 1674-1056
  eISSN: 2058-3834
• Record 185 of
  
  Title:Hyperspectral Image Reconstruction of SD-CASSI Based on Nonlocal Low-Rank Tensor Prior
  
  Author(s):Yin, Xiaorui; Su, Lijuan; Chen, Xin; Liu, Hejian; Yan, Qiangqiang; Yuan, Yan
  Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING  Volume: 62  Issue:   DOI: 10.1109/TGRS.2024.3398299  Published: 2024  
  Abstract:In single disperser coded aperture snapshot spectral imaging (SD-CASSI) systems, many methods have been developed to reconstruct hyperspectral images (HSIs) from compressed measurements. Among these, deep learning (DL)-based methods have stood out, relying on powerful DL networks. However, the solidified structure of DL-based methods limits their adaptability. Moreover, they are often based on a model that neglects the dispersion process and instead emphasizes the encoding-compression process. Furthermore, research on optimization-based methods designed especially for SD-CASSI is lacking. In this article, we propose a comprehensive two-step projection imaging model for SD-CASSI that includes both spectral shearing projection and encoding-compression projection. Based on this model, we derive a tensor-based optimization framework that incorporates with the nonlocal low-rank tensor (NLRT) prior. In particular, NLRT extracts inherent spatial structural information from the measurements and employs it to guide the clustering of spatial-spectral similar HSI blocks. A CANDECOMP/PARAFAC (CP) low-rank regularizer is introduced to constrain the low-rank property of HSI block clusters. After that, we develop a solution framework based on the alternating direction method of multiplier (ADMM) approach. Comprehensive experiments demonstrate that our NLRT method outperforms state-of-the-art methods in terms of flexibility and performance. The source code and data of this article are publicly available at https://github.com/sdnjyxr/NLRT.
  Accession Number: 5518015
  ISSN: 0196-2892
  eISSN: 1558-0644
• Record 186 of
  
  Title:Electron vortex generations in photoionization of hydrogen atoms by circularly-polarized chirped attosecond pulses
  
  Author(s):Zhang, Bingshuang; Liu, Xiaoyu; Zhu, Fengzheng; Jiao, Liguang; Liu, Aihua
  Source: COMMUNICATIONS IN THEORETICAL PHYSICS  Volume: 76  Issue: 1  DOI: 10.1088/1572-9494/ad1587  Published: 2024  
  Abstract:By numerically solving the time-dependent Schrodinger equation and employing the analytical perturbative model, we investigated the chirp-induced electron vortex in the photoionization of hydrogen atoms by a pair of counter-rotating circularly polarized chirped attosecond extremely ultraviolet pulses. We demonstrated that single-photon ionization of hydrogen atoms generates photoelectron momentum distributions (PMDs) with distinct helical vortex structures either with or without a time delay between two counter-rotating circularly polarized laser pulses. These structures are highly sensitive to both the time delay between the pulses and their chirp parameters. Our analytical model reveals that the splitting of vortex spirals is caused by the sign changing of the chirp-induced frequency-dependent time delay. We showed that to obtain the counterpart of the PMD under a pair of counter-rotating circularly polarized chirped pulses, both chirp parameters and ordering of pulses need to be reversed.
  Accession Number: 15502
  ISSN: 0253-6102
  eISSN: 1572-9494
• Record 187 of
  
  Title:Display method for high dynamic range infrared image based on gradient domain guided image filter
  
  Author(s):Zhang, Feifei; Dai, Yimian; Chen, Yaohong; Peng, Xuedian; Zhu, Xiongyong; Zhou, Ruqi; Wu, Yinlin; Peng, Junfeng
  Source: OPTICAL ENGINEERING  Volume: 63  Issue: 1  DOI: 10.1117/1.OE.63.1.013105  Published: 2024  
  Abstract:With the aim of handling the characteristics of infrared images, including their high dynamic range (HDR), low contrast, and blurry edges, this paper proposes an approach for displaying infrared images with gradient domain guided image filter (GIF). First, the original image is decomposed into base layer and detail layer by gradient domain GIF and Gaussian filter. Second, the adaptive double plateau histogram equalization method is used to compress the dynamic range and enhance the overall brightness of the base layer. Third, a detail gain factor is constructed to gain the detail layer, and then a display method for the detail layer is designed by considering the 3 sigma rule in Gaussian distributions. Finally, the processed base layer and detail layer are linearly fused to obtain the result image. The proposed method and five mainstream infrared image display methods are used to process infrared images collected in four different scenes. Subjective and objective evaluation methods are used to demonstrate that the proposed method is capable of compressing the dynamic range, improving the overall brightness and enhancing the local details, as well as displaying HDR infrared images with a high degree of fidelity.
  Accession Number:
  ISSN: 0091-3286
  eISSN: 1560-2303
• Record 188 of
  
  Title:A Novel Computational Imaging Algorithm for Electrical Capacitance Tomography
  
  Author(s):Zhao, Qing; Liu, Shi; Chen, Weining
  Source: APPLIED SCIENCES-BASEL  Volume: 14  Issue: 2  DOI: 10.3390/app14020587  Published: 2024  
  Abstract:High-precision images enable electrical capacitance tomography (ECT) to obtain more reliable measurement results, meaning that the reconstruction algorithm is particularly important. Some excellent numerical algorithms have successfully solved the inverse problem for ECT imaging, but their imaging quality is relatively low. To solve this problem, this paper proposes a new reconstruction algorithm based on regularized extreme learning machines (RELMs). The implementation of the algorithm is mainly divided into two steps: (1) according to a large number of training samples, the RELM model can be obtained by the iterative split Bregman (ISB) algorithm, which can describe the mapping relationship between the capacitance correlation coefficient and the imaging target well, and (2) the capacitance correlation coefficient is calculated, which is then used as input to the RELM model to predict the final imaging. Both simulation and experimental results show that the RELM algorithm achieves greater improvement in imaging quality and robustness, and provides new development ideas for the ECT.
  Accession Number: 587
  ISSN:
  eISSN: 2076-3417
• Record 189 of
  
  Title:Heterostructure nanocluster MOF-derived Ag-CuO: An emerging material for harmonic soliton pulses generation
  
  Author(s):Luo, Wenfeng; Sun, Penghuan; Wu, Ziyan; Ban, Xiaoqiang; Zhang, Tingting; Zhao, Yang; Li, Xiaohui; Yu, Xuechao; Shan, Guangcun; Zhao, Xiaoxia
  Source: INFRARED PHYSICS & TECHNOLOGY  Volume: 136  Issue:   DOI: 10.1016/j.infrared.2023.105052  Published: 2024  
  Abstract:In recent years, metal-organic framework (MOF) and their derivatives have attracted many researchers due to excellent characteristics, such as good stability, high capacity, and a modest third order nonlinear optical response. Compared with conventional optical materials, MOF-oxide are easier to benefit photonic research. However, for nonlinear optics and ultrafast photonics, research on MOFs-Transition metal oxide is still in its infancy. In this work, MOF-derived Ag-CuO was prepared by hydrothermal method and applied in passively mode-locked fiber laser. Experimental results show that MOF-derived Ag-CuO possesses excellent optical absorption, functioning as a saturable absorber (SA). The laser based on MOF-derived Ag-CuO SA realizes three different mode-locking states, including traditional soliton with the pulse width of 1.04 ps, 32nd order harmonic soliton molecule, and soliton rain pulse, with the signal-to-noise ratio (SNR) of 73 dB. This work lays the foundation of its application in ultrashort photonics and optical communication, broadening the future of MOFderived Ag-CuO.
  Accession Number: 105052
  ISSN: 1350-4495
  eISSN: 1879-0275
• Record 190 of
  
  Title:All-polarization-maintaining mode-locked Holmium-doped fiber laser based upon nonlinear polarization evolution
  
  Author(s):Tu, Lisha; Tang, Ziya; Li, Keyi; Wang, Jiachen; Lin, Hua; Zhang, Wenfei; Lue, Qitao; Guo, Chunyu; Ruan, Shuangchen
  Source: INFRARED PHYSICS & TECHNOLOGY  Volume: 136  Issue:   DOI: 10.1016/j.infrared.2023.105054  Published: 2024  
  Abstract:An all-polarization-maintaining, all-fiberized holmium (Ho) doped fiber laser mode-locked by nonlinear polarization evolution (NPE) is experimentally demonstrated for the first time. The NPE mechanism is realized via the combination of a polarizer and the cross-fusion of three sections of polarization maintaining (PM) fibers. With the appropriate manipulation of the splicing angles between the birefringent axes of the PM fibers, a highly stable mode locked operation is realized. The laser delivers stable dissipative-soliton resonance (DSR) pulses with a repetition rate of 10.34 MHz and an average power of 223.95 mW, corresponding to a pulse energy of 21.64 nJ and a peak power of 11 W. Furthermore, the output power test over 2 h implies superior stability of this design. The oscillator, performing the characteristics of self-starting, high pulse energy, and good stability, is attractive and promising for various practical application.
  Accession Number: 105054
  ISSN: 1350-4495
  eISSN: 1879-0275
• Record 191 of
  
  Title:Bi2O2S topological transformation and in-situ regrowth of [hk1]-oriented SbBiS3-xSex 2D skeleton structure for construction of efficient quasi-two-dimensional Sb2S3-xSex-based heterojunction photoanodes
  
  Author(s):Zhang, Liyuan; Liu, Xinyang; Liu, Dekang; Cheng, Yufei; Li, Qiujie; Wang, Yishan; Hu, Xiaoyun; Miao, Hui
  Source: SEPARATION AND PURIFICATION TECHNOLOGY  Volume: 334  Issue:   DOI: 10.1016/j.seppur.2023.125983  Published: 2024  
  Abstract:Antimony chalcogenides (Sb2S3-xSex), as one of the promising light-absorbing materials in optoelectronic energy storage devices, has attracted widespread attention in recent years. Of particular note, its crystal structure consists of the one-dimensional [Sb4S(Se)6]n ribbons with efficient carrier transport efficiency along the [hk1] direction. In this paper, with the aid of the topological transformation of the layered material Bi2O2S, the SbBiS3-xSex bimetallic alloy with 2D skeleton structure was induced to grow in situ, and the conversion of Sb2S3-xSex preferred orientation from [hk0] to [hk1] was realized. The corresponding results showed that 2D skeleton structure was conducive to the construction of photo traps and the increase of electrochemical specific surface area. In addition, Bi2O2S acted as an electron transport layer (ETL) to further promote the migration of photo-generated carriers. At 1.23 V vs. RHE, the photocurrent density of quasi-two-dimensional Bi2O2S/SbBiS3-xSex nanosheet photoanode was as high as 6.41 mA cm-2, which was 7.5 times that of pure Sb2S3-xSex, and the peak value of IPCE could reach 40.93%. This work undoubtedly opens up a new avenue for the designing high-efficiency antimony chalcogenides photoelectrodes.
  Accession Number: 125983
  ISSN: 1383-5866
  eISSN: 1873-3794
• Record 192 of
  
  Title:Space advanced technology demonstration satellite
  
  Author(s):Zhang, Xiaofeng; Chen, Wen; Zhu, Xiaocheng; Meng, Na; He, Junwang; Bi, Xingzi; Zhang, Yonghe; Shi, Qi; Li, Fei; Liu, Rui; Feng, Zhenggong; Liu, Liu; Li, Jinsong; Wu, Haichen; Xu, Dongxiao; Li, Taijie; Huang, Jiangjiang; Liu, Shuo; Li, Tiantong; Yu, Xiansheng; Gao, Yang; Zhou, Heng; Ban, Hanyu; Zhang, Yanli; Zhang, Yueting; Yang, Yingquan; He, Tao; Duan, Xuliang; Chen, Xin; Wang, Yamin; Sun, Antai; Zhang, Kuoxiang; Sun, Ying; Wang, Yaobin; Fan, Chengcheng; Xiong, Shaolin; Li, Xinqiao; Wen, Xiangyang; Ling, Zhixing; Sun, Xiaojin; Zhang, Chen; Bai, Xianyong; Wang, Zhanshan; Deng, Yuanyong; Tian, Hui; Yang, Jianfeng; Xue, Hongbo; Sang, Peng; Liu, Jinguo; Zheng, Huilong; Zhu, Xiang; He, Jianwu; Li, Hui; Xu, Luxiang; Xu, Shuyan; Chen, Wenwu; Liu, Zhendong; Wang, Zhaoli; Mao, Xianglong; Gao, Rong; Li, Zongxuan; Ding, Guopeng; Wang, Xinyu; Dou, Runjiang; Weng, Lubin; Luo, Hao; Wang, Yaping; Liang, Xianfeng; Fang, Ziruo
  Source: SCIENCE CHINA-TECHNOLOGICAL SCIENCES  Volume: 67  Issue: 1  DOI: 10.1007/s11431-023-2510-x  Published: 2024  
  Abstract:The Space Advanced Technology demonstration satellite (SATech-01), a mission for low-cost space science and new technology experiments, organized by Chinese Academy of Sciences (CAS), was successfully launched into a Sun-synchronous orbit at an altitude of similar to 500 km on July 27, 2022, from the Jiuquan Satellite Launch Centre. Serving as an experimental platform for space science exploration and the demonstration of advanced common technologies in orbit, SATech-01 is equipped with 16 experimental payloads, including the solar upper transition region imager (SUTRI), the lobster eye imager for astronomy (LEIA), the high energy burst searcher (HEBS), and a High Precision Magnetic Field Measurement System based on a CPT Magnetometer (CPT). It also incorporates an imager with freeform optics, an integrated thermal imaging sensor, and a multi-functional integrated imager, etc. This paper provides an overview of SATech-01, including a technical description of the satellite and its scientific payloads, along with their on-orbit performance.
  Accession Number:
  ISSN: 1674-7321
  eISSN: 1869-1900