Search

Your search keyword '"Zhang, Xuyu"' showing total 116 results
Start Over Author "Zhang, Xuyu"
116 results on '"Zhang, Xuyu"'

1. Nonconvex optimization for optimum retrieval of the transmission matrix of a multimode fiber

Author

Cheng, Shengfu, Zhang, Xuyu, Zhong, Tianting, Li, Huanhao, Li, Haoran, Gong, Lei, Liu, Honglin, and Lai, Puxiang

Subjects
Physics - Optics, Electrical Engineering and Systems Science - Signal Processing
Abstract

Transmission matrix (TM) allows light control through complex media such as multimode fibers (MMFs), gaining great attention in areas like biophotonics over the past decade. The measurement of a complex-valued TM is highly desired as it supports full modulation of the light field, yet demanding as the holographic setup is usually entailed. Efforts have been taken to retrieve a TM directly from intensity measurements with several representative phase retrieval algorithms, which still see limitations like slow or suboptimum recovery, especially under noisy environment. Here, a modified non-convex optimization approach is proposed. Through numerical evaluations, it shows that the nonconvex method offers an optimum efficiency of focusing with less running time or sampling rate. The comparative test under different signal-to-noise levels further indicates its improved robustness for TM retrieval. Experimentally, the optimum retrieval of the TM of a MMF is collectively validated by multiple groups of single-spot and multi-spot focusing demonstrations. Focus scanning on the working plane of the MMF is also conducted where our method achieves 93.6% efficiency of the gold standard holography method when the sampling rate is 8. Based on the recovered TM, image transmission through the MMF with high fidelity can be realized via another phase retrieval. Thanks to parallel operation and GPU acceleration, the nonconvex approach can retrieve an 8685$\times$1024 TM (sampling rate=8) with 42.3 s on a regular computer. In brief, the proposed method provides optimum efficiency and fast implementation for TM retrieval, which will facilitate wide applications in deep-tissue optical imaging, manipulation and treatment.

Published
2023

2. Different Channels to Transmit Information in a Scattering Medium

Author

Zhang, Xuyu, Gao, Jingjing, Gan, Yu, Song, Chunyuan, Zhang, Dawei, Zhuang, Songlin, Han, Shensheng, Lai, Puxiang, and Liu, Honglin

Subjects
Physics - Optics, J.2, H.1.m
Abstract

A channel should be built to transmit information from one place to another. Imaging is 2 or higher dimensional information communication. Conventionally, an imaging channel comprises a lens and free spaces of its both sides. The transfer function of each part is known; thus, the response of a conventional imaging channel is known as well. Replacing the lens with a scattering layer, the image can still be extracted from the detection plane. That is to say, the scattering medium reconstructs the channel for imaging. Aided by deep learning, we find that different from the lens there are different channels in a scattering medium, i.e., the same scattering medium can construct different channels to match different manners of source encoding. Moreover, we found that without a valid channel the convolution law for a shift-invariant system, i.e., the output is the convolution of its point spread function (PSF) and the input object, is broken, and information cannot be transmitted onto the detection plane. In other words, valid channels are essential to transmit image information through even a shift-invariant system., Comment: 10 pages, 4 figures

Published
2022

24. A nodal‐based evolutionary optimization algorithm for frame structures.

Author

Zhang, Xuyu, Xie, Yi Min, and Zhou, Shiwei

Subjects
*STRUCTURAL frames, *MATHEMATICAL optimization, *STRAIN energy, *EVOLUTIONARY algorithms, *ASYMPTOTES
Abstract

This work proposes a nodal‐based evolutionary design optimization algorithm to design frame structures whose edges are the Delaunay triangulation of homogeneously distributed nodes in the design domain. The remaining nodes can freely sway in the design domain except for the loading nodes and boundary nodes. As a result, it can extend the space of admissible solutions to this optimization problem and reduce the number of design variables. Then, the sensitivity of the objective function, namely, the sum of compliance and its volume, is input into the method of moving asymptotes to update the nodal coordinates and member thickness. The most inefficient node is deleted in each iteration based on the average nodal strain energy until its number reaches a prescribed limit. 2D numerical examples for the Michell arch, L‐shaped bracket, and Messerschmidt–Bölkow–Blohm beam show that the proposed algorithm can get the optimal structure within a few iterations. Compared with initial configurations in 3D, the optimal crane arm, transmission tower, and aquatic dome have less strain energy and fewer materials, showing a great potential of the proposed method to design actual space frames. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

31. 多模光纤远端光场重建的采样方案（特邀）

Author

甘雨 Gan Yu, 刘红林 Liu Honglin, 高敬敬 Gao Jingjing, 宋纯元 Song Chunyuan, 张栩瑜 Zhang Xuyu, and 韩申生 Han Shensheng

Subjects
Space and Planetary Science, Aerospace Engineering, Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics
Published
2022

38. UPLC–Q-TOF/MS-Based Plasma and Urine Metabolomics Contribute to the Diagnosis of Sepsis

Author

Guan, Su, Liu, Kun, Liu, Zimeng, Zhou, Liping, Jia, Bingjie, Wang, Zichen, Nie, Yao, and Zhang, Xuyu

Abstract

In this study, we aimed to identify potential metabolic biomarkers that can improve the diagnostic accuracy of sepsis. Sixty-six patients including 30 septic and 36 nonsepsis patients from an intensive care unit were recruited. The global plasma and urine metabolomic profiles were determined by ultraperformance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometry-based methodology. The risk factors, including both traditional physiological indicators and metabolic biomarkers, were investigated by binary logistic regression analysis and used to build a least absolute shrinkage and selection operator (Lasso) regression model to evaluate the ability of diagnosis. Fifty-five metabolites in plasma and 11 metabolites in urine were identified through orthogonal projections to latent structures discriminant analysis (OPLS-DA). Among them, ten (PE (20:4(5Z, 8Z, 11Z, 14Z)/P-18:0), harderoporphyrinogen, chloropanaxydiol, (Z)-2-octenal, N1,N8-diacetylspermidine, 1-nitroheptane, venoterpine, α-CEHC, LysoPE (20:0/0:0), corticrocin) metabolites were identified as risk factors. The Lasso regression model incorporating these ten metabolic biomarkers and five traditional physiological indicators displayed better differentiation than the traditional model, represented by the elevated area under receiver operating characteristic curve (AUROC) from 96.80 to 100.0%. Furthermore, patients with septic shock presented a significantly lower level of PE-Cer (d16:1(4E)/19:0). This study suggests that metabolomic profiling could be an effective tool for sepsis diagnosis.

Published
2022
Full Text
View/download PDF

47. Suppression of glioblastoma growth and angiogenesis through molecular targeting of methionine aminopeptidase-2.

Author

Lin, Ming, Zhang, Xuyu, Jia, Bingjie, and Guan, Su

Abstract

Methionine aminopeptidases (MetAPs) have been pharmacologically linked to cell growth, angiogenesis, and tumor progression, which make it an attractive target for cancer therapy. We investigated MetAP2's biological role in glioblastoma (GBM), an aggressive tumor characterized by massive neovascularization. We examined the effect of anti-MetAP2 RNA interference on proliferation and angiogenesis in GBM cell line. The biological effects of MetAP2 knockdown were assessed by comparing the proliferation, tumorigenecity, and angiogenesis of parental cells and MetAP2 knockdown cells. We generated MetAP2 knockdown cells using lentiviral short hairpin RNAs against MetAP2 in SNB19 GBM cells, which normally express high levels of MetAP2. MetAP2 knockdown cells were less proliferative and less tumorigenic when compared to the parental cells. MetAP2 knockdown decreased vascular endothelial growth factor (VEGF) secretion and expression at the mRNA and protein levels. Decreased VEGF expression in MetAP2 knockdown cells correlated very well with decreased vessel formation in a tube formation assay. We showed that VEGF suppression in MetAP2 knockdown cells was mediated by the von Hippel-Lindau protein. In in vivo animal studies using an intracranial SNB19 tumor model, MetAP2 knockdown also reduced the tumor growth rate and angiogenesis, which in turn prolonged the survival of mice in xenograft model. Our results show that MetAP2 regulates angiogenesis in GBM and identify MetAP2-specific substrates that may serve as candidates for clinical assay development. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results