133 results on '"Dongxia, Hu"'
Search Results
2. Associations between blood inflammatory markers and bone mineral density and strength in the femoral neck: findings from the MIDUS II study
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Zixi Huang, Zhenyan Xu, Rong Wan, Dongxia Hu, and Ying Huang
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Medicine ,Science - Abstract
Abstract Chronic and systematic inflammation have been related to increased risks of osteopenia and related fracture. However, studies concerning the association between low-grade inflammation and the bone mineral density (BMD) and strength of the femoral neck are still few and inconsistent. This study aimed to examine the relationships between blood inflammatory biomarkers and BMD and femoral neck strength in an adult-based cohort. We retrospectively analyzed a total of 767 participants included in the Midlife in the United States (MIDUS) study. The blood levels of inflammatory markers, including interleukin-6 (IL6), soluble IL-6 receptor, IL-8, IL-10, TNF-α and C-reactive protein (CRP), in these participants were measured, and their associations with the BMD and strength of the femoral neck were determined. We analyzed these 767 subjects with data concerning the BMD, bending strength index (BSI), compressive strength index (CSI), and impact strength index (ISI) in the femoral neck and inflammatory biomarkers. Importantly, our results suggest that strongly negative associations exist between the blood soluble IL6 receptor levels and the BMD (per SD change, Sβ = −0.15; P
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- 2023
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3. Construction and Validation of Surface Soil Moisture Inversion Model Based on Remote Sensing and Neural Network
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Rencai Lin, Zheng Wei, Rongxiang Hu, He Chen, Yinong Li, Baozhong Zhang, Fengjing Wang, and Dongxia Hu
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surface soil moisture ,water cloud model ,RBF network ,remote sensing ,Meteorology. Climatology ,QC851-999 - Abstract
Surface soil moisture (SSM) reflects the dry and wet states of soil. Microwave remote sensing technology can accurately obtain regional SSM in real time and effectively improve the level of agricultural drought monitoring, and it is of great significance for agricultural precision irrigation and smart agriculture construction. Based on Sentinel-1, Sentinel-2, and Landsat-8 images, the effect of vegetation was removed by the water cloud model (WCM), and SSM was retrieved and validated by a radial basis function (RBF) neural network model in bare soil and vegetated areas, respectively. The normalized difference vegetation index (NDVI) calculated by Landsat-8 (NDVI_Landsat-8) had a better effect on removing the influence the of vegetation layer than that of NDVI_Sentinel-2. The RBF network model, established in a bare area (R = 0.796; RMSE = 0.029 cm3/cm3), and the RBF neural network model, established in vegetated areas (R = 0.855; RMSE = 0.024 cm3/cm3), have better simulation effects on SSM than a linear SSM inversion model with single polarization. The introduction of surface parameters to the RBF neural network model can improve the accuracy of the model and realize the high-accuracy inversion of SSM in the study area.
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- 2024
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4. Integrated Wavefront Sensing and Processing Method Utilizing Optical Neural Network
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Gang Luo, Yuanchao Geng, Deen Wang, Qiang Yuan, Dongxia Hu, and Wanguo Zheng
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optics in computing ,wavefront sensing ,adaptive optics ,Applied optics. Photonics ,TA1501-1820 - Abstract
Wavefront sensors and processors are vital components of adaptive optical (AO) systems, directly impacting the operating bandwidth. As application scenarios become increasingly complex, AO systems are confronted with more extreme atmospheric turbulence. Additionally, as optical systems scale up, the data processing demands of AO systems increase exponentially. These challenges necessitate advancements in wavefront sensing and processing capabilities. To address this, this paper proposes an integrated wavefront sensing and processing method based on the optical neural network architecture, capable of directly providing control coefficients for the wavefront corrector. Through simulation and experimentation, this method demonstrates high sensing precision and processing speed, promising to realize large-scale, high-bandwidth AO systems.
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- 2024
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5. A Novel Method for Precision Measurement and Result Optimization of Detuning Angle for KDP Crystals.
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Honghong Wu, Guoqing Pei, Dongya Chu, Yuting Wu, Han Gu, Siyu Wu, Chenzhuo Wang, Wanlai Zhu, Hai Zhou, and Dongxia Hu
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- 2024
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6. Optical Isolation of the Amplifier Cavity in XG-III PW Beamline
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Zhenhai Wu, Jiao Long, Jun Zhang, Qian Xiong, Xiongjun Zhang, and Dongxia Hu
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laser amplification ,optical isolation ,Pockels cells ,polarizer ,Optics. Light ,QC350-467 ,Applied optics. Photonics ,TA1501-1820 - Abstract
Optical isolation with high-quality, large-aperture polarizers is commonly used in high-power laser facilities to suppress retro-reflected pulses. However, it is hard to manufacture these polarizers. We propose an approach of optical isolation with two plasma-electrode Pockels cells instead of large-aperture polarizers. In this approach, Nd:glass slabs placed at the Brewster′s angle are used as polarizers. The analysis results and the application performances in the Xingguang (Star Light) XG-III PW beamline indicate that this approach can supply good protection to optical components in laser facilities.
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- 2023
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7. Effects of volatile organic contamination on the performance of dielectric film
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Hongjie, Liu, Fang, Wang, Shutong, Wang, Laixi, Sun, Tianran, Zheng, Yuan, Chen, Xiaodong, Yuan, Dongxia, Hu, and Qihua, Zhu
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- 2022
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8. Compensatory movement detection by using near-infrared spectroscopy technology based on signal improvement method
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Xiang Chen, YinJin Shao, LinFeng Zou, SiMin Tang, Zhiwei Lai, XiaoBo Sun, FaWen Xie, Longhan Xie, Jun Luo, and Dongxia Hu
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compensatory movement detection ,near-infrared spectroscopy ,support vector machine ,rehabilitation training ,differential based signal improvement ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
IntroductionCompensatory movements usually occur in stroke survivors with hemiplegia, which is detrimental to recovery. This paper proposes a compensatory movement detection method based on near-infrared spectroscopy (NIRS) technology and verifies its feasibility using a machine learning algorithm. We present a differential-based signal improvement (DBSI) method to enhance NIRS signal quality and discuss its effect on improving detection performance.MethodTen healthy subjects and six stroke survivors performed three common rehabilitation training tasks while the activation of six trunk muscles was recorded using NIRS sensors. After data preprocessing, DBSI was applied to the NIRS signals, and two time-domain features (mean and variance) were extracted. An SVM algorithm was used to test the effect of the NIRS signal on compensatory behavior detection.ResultsClassification results show that NIRS signals have good performance in compensatory detection, with accuracy rates of 97.76% in healthy subjects and 97.95% in stroke survivors. After using the DBSI method, the accuracy improved to 98.52% and 99.47%, respectively.DiscussionCompared with other compensatory motion detection methods, our proposed method based on NIRS technology has better classification performance. The study highlights the potential of NIRS technology for improving stroke rehabilitation and warrants further investigation.
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- 2023
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9. UNet-Based Framework for Predicting the Waveform of Laser Pulses of the Front-End System in a Current High-Power Laser Facility
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Yuzhen Liao, Xiaoxia Huang, Yuanchao Geng, Qiang Yuan, and Dongxia Hu
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prediction of laser performance ,temporal shape of laser pulses ,UNet prediction ,data mining ,precise regulation ,Applied optics. Photonics ,TA1501-1820 - Abstract
Performing data mining on large waveform datasets of a high-power laser facility is an important way to achieve precise regulation of a device. However, there are currently issues with missing values, noise, and inconsistency in this database of measuring pulse waveform in a current high-power laser facility. In this paper, a UNet of a series residual module is presented to predict the pulse waveform of a front-end chained system in a current high-power laser facility. The designed network is trained on grouped sequences formed by experimentally measuring pulse waveforms of a high-power laser facility. The strategies of relay output and relay loss are employed in training in order to enable the network to predict two kinds of pulse waveforms simultaneously. The trained network achieved an RMSE of 3.38% on the testing set of measuring pulse waveform at a frequency of 1 Hz, and an RMSE of 0.84% on the testing set of setting the voltage of the Arbitrary Waveform Generator (AWG). These results indicate that this method can accurately fill in paired missing values in the waveform database of a high-power laser facility. The main advantage of this method is that it can quickly couple operational parameters for prediction, and this method can be applied to predicting laser performance, cleaning one-dimensional sequences, and maintaining a waveform database.
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- 2023
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10. Mode‐dependent switching control of bilateral teleoperation against random denial‐of‐service attacks
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Lingyan Hu, Kun Wang, Dongxia Hu, and Yiming Wang
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delays ,control engineering computing ,telerobotics ,stochastic systems ,computer network security ,tracking ,Computer engineering. Computer hardware ,TK7885-7895 ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Abstract As communication networks are implemented for information exchange between the master and slave sides of bilateral teleoperation systems, they are exposed to cyber‐attack threats. This paper aims to analyse the performance of bilateral teleoperation systems in the presence of random denial‐of‐service (DoS) attacks and constant transmission delays and propose a mode‐dependent switching controller to mitigate the influence of DoS attacks. The characteristics of DoS attacks and networks are thoroughly incorporated in the design; also considered is the case of both communication directions behaving independently. Specifically, the model of a teleoperation system under a DoS attack is integrated as a stochastic jump system. A mode‐dependent control approach is proposed for a teleoperation system to mitigate the influence of random DoS attacks. In case studies, vulnerability analysis and time‐domain simulation results show that teleoperation system performance can be degraded under continuous random DoS attacks. When the proposed mode‐based switching controllers are installed, the trajectory tracking performance and authenticity of interaction force feedback are significantly improved during the attacking period.
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- 2022
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11. Interpretable evaluation for the Brunnstrom recovery stage of the lower limb based on wearable sensors
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Xiang Chen, DongXia Hu, RuiQi Zhang, ZeWei Pan, Yan Chen, Longhan Xie, Jun Luo, and YiWen Zhu
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rehabilitation evaluation ,Brunnstrom recovery stage ,wearable sensor ,machine learning ,feature importance ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
With the increasing number of stroke patients, there is an urgent need for an accessible, scientific, and reliable evaluation method for stroke rehabilitation. Although many rehabilitation stage evaluation methods based on the wearable sensors and machine learning algorithm have been developed, the interpretable evaluation of the Brunnstrom recovery stage of the lower limb (BRS-L) is still lacking. The paper propose an interpretable BRS-L evaluation method based on wearable sensors. We collected lower limb motion data and plantar pressure data of 20 hemiplegic patients and 10 healthy individuals using seven Inertial Measurement Units (IMUs) and two plantar pressure insoles. Then we extracted gait features from the motion data and pressure data. By using feature selection based on feature importance, we improved the interpretability of the machine learning-based evaluation method. Several machine learning models are evaluated on the dataset, the results show that k-Nearest Neighbor has the best prediction performance and achieves 94.2% accuracy with an input of 18 features. Our method provides a feasible solution for precise rehabilitation and home-based rehabilitation of hemiplegic patients.
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- 2022
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12. Design of online damage images detection system for large-aperture mirrors of high power laser facility based on wavefront coding technology
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Fang, Wang, Qinxiao, Liu, Dongxia, Hu, Hongjie, Liu, and Tianran, Zheng
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- 2021
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13. Blood hemoglobin A1c might predict adverse differences in heart rate variability in a diabetic population: Evidence from the Midlife in the United States (MIDUS) study
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Ying Huang, Hong Chen, Dongxia Hu, and Rong Wan
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automatic nervous system ,HbA1c ,heart rate variability ,cardiac autonomic neuropathy ,diabetes mellitus ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
BackgroundCardiac autonomic neuropathy in population with diabetes mellitus (DM) is frequent and linked with high risk of cardiovascular mortality. However, studies on whether blood hemoglobin A1c (HbA1c) levels are related to adverse differences in heart rate variability (HRV) in individuals with DM are scarce.AimWe aimed to investigate the association of blood HbA1c levels with adverse differences in HRV, which is an indicator of cardiac autonomic control, in adult individuals with and without DM.MethodsData were collected from the Midlife in the United States (MIDUS) study, and 928 individuals were analyzed for the relationship between blood HbA1c levels and HRV through a cross-sectional analysis.ResultsParticipants with DM had significantly higher HRV than those without DM. The smooth curve suggested inverse relationships between blood HbA1c levels and HF- and LF-HRV seen in participants with DM but not in those without DM after controlling for all covariates (age, sex, BMI, smoking, number of drinking years and exercise). Furthermore, linear regression analysis demonstrated that elevated blood HbA1c levels did contribute to adverse differences in HF-HRV (Sβ= -0.118; 95% CI -0.208, -0.027; P=0.012) and LF-HRV (Sβ= -0.097; 95% CI -0.177, -0.017; P=0.019) after controlling for these covariates in participants with DM, while in participants without DM, blood HbA1c was not significantly related to adverse differences in HF-HRV (Sβ=0.095; 95% CI -0.059, 0.248; P=0.228) or LF-HRV (Sβ=0.043; 95% CI -0.103, 0.189; P=0.565). DM has a significant modifying effect on associations between blood HbA1c and adverse differences in HF-HRV (P for interaction=0.019) and LF-HRV (P for interaction=0.029).ConclusionsWe reported strong evidence that elevated blood levels of HbA1c were associated with adverse differences in HRV in the diabetic population but not in the nondiabetic population. This finding supported that long-term hyperglycemia is related to autonomic nerve injury in the diabetic population. Blood HbA1c might be a good indicator of cardiac autonomic neuropathy.
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- 2022
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14. Diode-Pumped 50 Hz–10 J Nano-Second Nd:YAG Laser
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Xinying Jiang, Kaibo Xiao, Xiongwei Yan, Zhenguo Wang, Xuejun Jiang, Qiao Xue, Wenlong Wu, Ji Chen, Chuanchao Zhang, Jiangang Zheng, Zhitao Peng, Kuixing Zheng, Ping Li, Dongxia Hu, Qihua Zhu, and Wanguo Zheng
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re-frequency pulse laser ,high-energy laser ,high conversion efficiency ,thermal management ,Nd:YAG laser ,Physics ,QC1-999 - Abstract
In this letter, we report a diode-pumped nano-second laser with the output energy 10 J, the repetition rate 50 Hz, and the average power 500 W. The main amplifier was made up of eight amplify modules. Each amplify module was pumped by an 808 nm laser diode and cooled by water from the back end of the Nd:YAG slab. To our knowledge, this represents the highest pulse repetition rate for the 10 J class nano-second single-aperture Nd:YAG laser. The beam quality was controlled by means of mechanical design and adjustment and compensation by a home-made deforming mirror. The beam quality was controlled well with the beam quality of the laser 2.61DL.
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- 2022
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15. Beam wavefront retrieval by convoluted spatial spectral benchmark
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Xuewei Deng, Xiaoxia Huang, Deen Wang, Ying Yang, Xin Zhang, and Dongxia Hu
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Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
We propose a method for retrieving a beam wavefront from its near-field intensity distribution after a 4f system by simply inserting a benchmark at the Fourier plane. Through a convolution of the mark-blocked spatial frequency component and the original optical field with the 4f system, the separation between the focus of any sub-aperture and the benchmark can be determined to reconstruct the beam wavefront. Theoretical and experimental studies demonstrate the validity of this method, which has potential applications in real-time wavefront sensing.
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- 2021
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16. Quantitative Analysis of Adhesion Characteristics between Crumb Rubber Modified Asphalt and Aggregate Using Surface Free Energy Theory
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Ning Li, Jie Wang, Wei Si, and Dongxia Hu
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crumb rubber modified asphalt ,adhesion characteristics ,surface free energy ,adhesion work ,spalling work ,water stability ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
The utilization of waste rubber tires is of great value for environment protection and resource recovery, which can also improve the properties of matrix asphalt. The adhesion characteristics were evaluated for crumb rubber modified asphalt and limestone aggregate using the surface free energy (SFE) approach. Four types of matrix asphalt and four rubber contents were used to prepare the crumb rubber modified asphalt. The contact angle of matrix and crumb rubber modified asphalt was obtained, and the SFE indicators (dispersion, polar component, and compatibility rate—CR) were calculated. Moreover, the water stability tests were conducted using one matrix and rubber modified asphalt in order to investigate the relationship between SFE and water stability indicators. Results showed that the total SFE, dispersion component, adhesion work, and CR increased with the addition of crumb rubber, while the polar component and spalling work decreased. The types of asphalt had different influences on SFE indicators. The results from analysis of variation (ANOVA) indicated asphalt type and rubber content had significant influence on the adhesion work, spalling work and CR, and the influence of asphalt type was greater than that of rubber content. Additionally, the retained Marshall Stability and tensile strength ratio had better correlation with adhesion work and CR, but less with spalling work. The presented results demonstrated that the type of matrix asphalt played an important role in the adhesion characteristics for the crumb rubber modified asphalt.
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- 2022
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17. Size Measurement of Laser-Induced Damage in Large-Aperture Final Optics.
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Guodong Liu, Fupeng Wei, Fengdong Chen, Zhitao Peng, Jun Tang, Bingguo Liu, Qihua Zhu, Dongxia Hu, Bin Feng, Yong Xiang, and Chengcheng Wang
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- 2018
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18. Laser performance upgrade for precise ICF experiment in SG-Ⅲ laser facility
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Wanguo Zheng, Xiaofeng Wei, Qihua Zhu, Feng Jing, Dongxia Hu, Xiaodong Yuan, Wanjun Dai, Wei Zhou, Fang Wang, Dangpeng Xu, Xudong Xie, Bin Feng, Zhitao Peng, Liangfu Guo, Yuanbin Chen, Xiongjun Zhang, Lanqin Liu, Donghui Lin, Zhao Dang, Yong Xiang, Rui Zhang, Huaiting Jia, and Xuewei Deng
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Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
The SG-Ⅲ laser facility (SG-Ⅲ) is the largest laser driver for inertial confinement fusion (ICF) researches in China, which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns. In order to meet the requirements of precise physics experiments, some new functionalities need to be added to SG-Ⅲ and some intrinsic laser performances need upgrade. So at the end of SG-Ⅲ's engineering construction, the 2-year laser performance upgrade project started. This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ. With these function extensions and performance upgrade, SG-Ⅲ is now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.
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- 2017
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19. Wavefront control of main-amplifier system in the SG-Ⅲ laser facility
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De’en, Wang, Dongxia, Hu, Qiang, Yuan, Qiao, Xue, Wei, Zhou, Ying, Yang, Xin, Zhang, Xuewei, Deng, Yuancheng, Wang, Junpu, Zhao, Wu, Deng, Xiaofeng, Wei, Wanjun, Dai, Feng, Jing, Qihua, Zhu, and Wanguo, Zheng
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- 2017
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20. Multi-feature fusion method based on WOSF and MSE for four-class MI EEG identification.
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Lingyan Hu, Jingjing Xie, Changhui Pan, Xiaolong Wu, and Dongxia Hu
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- 2021
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21. Characteristics of UV-induced bulk damage in large-aperture fused silica from full-sized beam tests
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Ye Tian, Xiaodong Yuan, Dongxia Hu, Qihua Zhu, and Wei Han
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Physics ,QC1-999 - Abstract
Laser-induced bulk damage in fused silica is studied on a large-aperture laser system with 6 J/cm2, 5-ns shot sequences at 351 nm. The lateral dimension of bulk damage is found to propagate exponentially with shot number in a wide range of growth rates, similar to the stochastic trend as displayed by rear-surface damage. Resemblance in the morphology between bulk and surface damage is revealed offline by microscopic observations. Arising from the accumulated effect of fluence variation, the repetitive laser exposures tend to create an increased number of bulk damage, the tendency of which is applied to evaluate the number of damage initiations via simulations.
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- 2018
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22. Elevated Blood Malondialdehyde Level Contributed to a High Stroke Risk in a Chinese Elderly Population from Rural Areas
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Rong Wan, Yuhao Su, Meilan Zhu, MD. Dongxia Hu, and Ying Huang
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Background: Individuals living in rural areas had higher incidence rate for stroke than their urban counterparts in China. However, few studies investigated on the association between blood malondialdehyde (MDA), an end product of lipid oxidation caused by reactive oxygen species (ROS), and stroke risk in rural population. Aim: We aimed to investigate whether blood MDA level contributes to a higher stroke risk in a Chinese elderly population from rural areas. Methods: Data from 2011-2012 of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), a national cohort of older adults in China were analyzed. Smooth curve and multivariable correction analysis were used to evaluate the association between blood MDA level and stroke risk in the elderly populations from rural and urban areas respectively. Results: The median age of all inluded participants (N=1598) was 84 years. The results of smooth curve model revealed a gradual upward trend on association of blood MDA levels with stroke risk in rural participants but not in urban participants. Similarly, the conditional logistic regression analysis suggested a significant association MDA levels with stroke risk in rural participants but not in urban participants after adjustments of related confounding factors (age, gender, current smoker, current drinker, current exercise, BMI and cardiovascular diseases (hypertension, heart disease, atrial fibrillation and diabetes) were made. Conclusion: Among the elderly population in China, elevated blood MDA levels were associated with increased stroke risk in rural participants but not in urban participants.
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- 2023
23. Progress in octahedral spherical hohlraum study
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Ke Lan, Jie Liu, Zhichao Li, Xufei Xie, Wenyi Huo, Yaohua Chen, Guoli Ren, Chunyang Zheng, Dong Yang, Sanwei Li, Zhiwen Yang, Liang Guo, Shu Li, Mingyu Zhang, Xiaoying Han, Chuanlei Zhai, Lifei Hou, Yukun Li, Keli Deng, Zheng Yuan, Xiayu Zhan, Feng Wang, Guanghui Yuan, Haijun Zhang, Bobin Jiang, Lizhen Huang, Wei Zhang, Kai Du, Runchang Zhao, Ping Li, Wei Wang, Jingqin Su, Xuewei Deng, Dongxia Hu, Wei Zhou, Huaiting Jia, Yongkun Ding, Wanguo Zheng, and Xiantu He
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Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
In this paper, we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study. From our theoretical study, the octahedral spherical hohlraums with 6 Laser Entrance Holes (LEHs) of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7. In addition, the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology. We studied the laser arrangement and constraints of the octahedral spherical hohlraums, and gave a design on the laser arrangement for ignition octahedral hohlraums. As a result, the injection angle of laser beams of 50°–60° was proposed as the optimum candidate range for the octahedral spherical hohlraums. We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields, in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport. We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums, the rugby hohlraums and the cylindrical hohlraums, and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive. Up till to now, we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG) laser facilities, including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums, spherical hohlraum energetics on the SGIII prototype laser facility, and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.
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- 2016
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24. CNN-based neural network model for amplified laser pulse temporal shape prediction with dynamic requirement in high-power laser facility
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Lu Zou, Yuanchao Geng, Bingguo Liu, Fengdong Chen, Wei Zhou, Zhitao Peng, Dongxia Hu, Qiang Yuan, Guodong Liu, and Lanqin Liu
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Atomic and Molecular Physics, and Optics - Abstract
The temporal shape of laser pulses is one of the essential performances in the inertial confinement fusion (ICF) facility. Due to the complexity and instability of the laser propagation system, it is hard to predict the pulse shapes precisely by pure analytic methods based on the physical model [Frantz-Nodvik (F-N) equation]. Here, we present a data-driven model based on a convolutional neural network (CNN) for precise prediction. The neural network model introduces sixteen parameters neglected in the F-N equation based models to expand the representation dimension. The sensitivity analysis of the experimental results confirms that these parameters have different degrees of influence on the temporal output shapes and cannot be ignored. The network characterizes the whole physical process with commonality and specificity features to improve the description ability. The prediction accuracy evaluated by a root mean square of the proposed model is 7.93%, which is better compared to three optimized physical models. This study explores a nonanalytic methodology of combining prior physical knowledge with data-driven models to map the complex physical process by numerical models, which has strong representation capability and great potential to model other measurable processes in physical science.
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- 2022
25. Mode‐dependent switching control of bilateral teleoperation against random denial‐of‐service attacks
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Lingyan Hu, Yiming Wang, Dongxia Hu, and Kun Wang
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Mode (computer interface) ,Artificial Intelligence ,Computer Networks and Communications ,Computer science ,business.industry ,Teleoperation ,Control (management) ,Denial-of-service attack ,Electrical and Electronic Engineering ,business ,Computer Science Applications ,Information Systems ,Computer network - Published
- 2021
26. Research on peripheral clamping of large-aperture laser transport mirror.
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TINGFEN CAO, BOWU LIU, HUI WANG, WEI NI, JINLI ZHANG, XIAOJUAN CHEN, YINGANG LI, HAI ZHOU, XIAODONG JIANG, DONGXIA HU, and QIHUA ZHU
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HIGH power lasers ,BENDING moment ,LASERS ,MIRRORS - Abstract
This article introduces the study of peripheral clamping for large-aperture laser mirrors in high power laser facilities. Some multi-point clamping schemes were experimentally tested, the results of the experiments show that these schemes cannot meet the technical requirements, and in the simulation analysis, we explain the reason for this phenomenon. It is concluded that the additional bending moment caused by the non-ideal process factors in the multi-point clamping is the main cause for the surface distortion. Based on the above conclusions, we carried out research on minor-point clamping. Experimental verification of the minor-point clamping were done, the results show that the minor-point clamping can meet the requirements of technical indicators in whole process. This work can provide a reference for the design of the large-aperture transport mirror clamping structure, which may be used in huge laser devices and telescopes. [ABSTRACT FROM AUTHOR]
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- 2023
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27. Energy prediction with physics-guided neural networks for high-power laser facility
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Lu Zou, Yuanchao Geng, Guodong Liu, Lanqin Liu, Bingguo Liu, Fengdong Chen, Wei Zhou, Dongxia Hu, and Qiang Yuan
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- 2022
28. Experimental Investigation of Water-Retaining and Mechanical Behaviors of Unbound Granular Materials under Infiltration
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Ning Li, Yuxiang Tian, Biao Ma, and Dongxia Hu
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permeable pavement ,Environmental effects of industries and plants ,Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,plastic strain ,TJ807-830 ,Management, Monitoring, Policy and Law ,infiltration ,TD194-195 ,CBR ,Renewable energy sources ,water-retaining ,unbound granular materials ,resilient strain ,Environmental sciences ,GE1-350 - Abstract
Unbound granular materials (UGM) in permeable pavement will experience large numbers of infiltration during their service-life. The frequently changed moisture not only affects the cooling effect of permeable pavement, but also influences the mechanical behaviors of UGM. However, evidence is lacking to state the influence of infiltration on the behaviors of UGM, which is commonly in fully permeable pavement. Considering the influence of infiltration, this study conducted experimental tests to investigate the effect on the water-retaining and bearing capacity of UGM. With the water-retaining tests, the water-retaining rate in the whole structure and at different depths was analyzed under different infiltration numbers and duration. The results showed that the water-retaining rate increased with the extension of the infiltration duration. The infiltration duration had a significant influence on the water-retaining capacity of UGM, while the infiltration number had little. The difference in the water-retaining rate between the top and bottom layers was up to 2.56%. The water-retaining capacity of the integrated structure was hardly affected due to the dissimilarity of the water-retaining rate at different depths. With infiltrations, the fine aggregate in the upside structure migrated downward to the lower structure, resulting in a reduction in water-retaining rate in the upper structure and an increase at the bottom. In addition, the mechanical behaviors were evaluated by the traditional California Bearing Ratio (CBR) and repeated CBR tests under five infiltrations. The first and second infiltration had a significant influence on the CBR of UGM. With two infiltrations, the plastic strain increased by 57.8% via the repeated CBR tests. The resilient strain had an increase by 36.52% and the equivalent modulus decreased by 28.7% with the first infiltration. The first infiltration presented a critical influence on the bearing capacity of UGM and the effect decreased with the increase in the infiltration number. These findings will enrich the behaviors investigation of UGM and promote its application in the fully permeable pavement.
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- 2022
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29. Novel Method for Measuring the Detuning Angle of Kdp Crystals Based on a Diverging Beam
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Dongya Chu, Liu Bowu, Pei Guoqing, Tian Menjiya, Wang Hui, and Dongxia Hu
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
30. Laser energy prediction with ensemble neural networks for high-power laser facility
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Lu, Zou, primary, Yuanchao, Geng, additional, Guodong, Liu, additional, Lanqin, Liu, additional, Fengdong, Chen, additional, Bingguo, Liu, additional, Dongxia, Hu, additional, Wei, Zhou, additional, and Zhitao, Peng, additional
- Published
- 2022
- Full Text
- View/download PDF
31. Icariside II protects cardiomyocytes from hypoxia-induced injury by upregulating the miR-7-5p/BTG2 axis and activating the PI3K/Akt signaling pathway
- Author
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Dongxia Hu, Juanjuan Zhang, Gu Yong, Qing Li, Bo Zhu, Dan Wu, Zhen Yuan, Shaochuan Li, and Jun Luo
- Subjects
Cell Survival ,Cell ,icariside II ,Myocardial Infarction ,Apoptosis ,cardiomyocyte ,Flow cytometry ,Immediate-Early Proteins ,Phosphatidylinositol 3-Kinases ,Downregulation and upregulation ,Genetics ,medicine ,Animals ,Myocytes, Cardiac ,PI3K/AKT/mTOR pathway ,Cells, Cultured ,Flavonoids ,PI3K/Akt ,BTG2 ,medicine.diagnostic_test ,Chemistry ,Akt/PKB signaling pathway ,hypoxia ,Tumor Suppressor Proteins ,General Medicine ,Articles ,Cell biology ,Rats ,Up-Regulation ,microRNA-7-5p ,Blot ,MicroRNAs ,medicine.anatomical_structure ,BTG anti-proliferation factor 2 ,Proto-Oncogene Proteins c-akt ,Signal Transduction - Abstract
Icariside II (ICS II) has been reported to have protective effects against oxidative stress. However, whether ICS II protects cardiomyocytes from myocardial infarction (MI), and the associated underlying mechanisms, remain to be elucidated. Therefore, the current study investigated the effects of ICS II on hypoxia‑injured H9c2 cells, as well as the associated molecular mechanisms. A hypoxic injury model was established to emulate the effects of MI. The effects of ICS II on the proliferation of rat cardiomyocyte H9c2 cells were assessed with cell counting kit‑8 assays. The apoptotic status of the cells was assessed by flow cytometry, and the expression of apoptosis‑related proteins was analyzed by western blotting. A microRNA (miRNA/miR) microarray was used to quantify the differential expression of miRNAs after ICS II treatment, and the levels of miR‑7‑5p were further quantified by reverse transcription‑quantitative PCR. Whether ICS II affected hypoxia‑injured cells via miR‑7‑5p was subsequently examined, and the target of miR‑7‑5p was also investigated by bioinformatics analysis and luciferase reporter assays. The effects of ICS II on the PI3K/Akt pathway were then evaluated by western blot analysis. Hypoxia treatment decreased viability and the migration and invasion abilities of H9c2 cells, and also induced apoptosis. ICS II significantly increased viability and reduced hypoxia‑associated apoptosis. Moreover, ICS II treatment led to the upregulation of miR‑7‑5p, and the protective effects of ICS II were found to rely on miR‑7‑5p. Moreover, BTG anti‑proliferation factor (BTG2) was identified as a direct target of miR‑7‑5p, and overexpression of BTG2 inhibited the protective effects of miR‑7‑5p. Finally, ICS II treatment resulted in the activation of the PI3K/Akt signaling pathway, which is essential for the survival of H9c2 cells under hypoxic conditions. In summary, ICS II reduces hypoxic injury in H9c2 cells via the miR‑7‑5p/BTG2 axis and activation of the PI3K/Akt signaling pathway.
- Published
- 2020
32. Optical element sub-surface defect detection combining fluorescence and scattering imaging
- Author
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Rui Dong, Fang Wang, Ye Tian, Qinxiao Liu, Liu Hongjie, and Dongxia Hu
- Subjects
Lossless compression ,Materials science ,Photoluminescence ,Microscope ,business.industry ,Scattering ,Image processing ,Laser ,Homogenization (chemistry) ,law.invention ,Optics ,Experimental system ,law ,business - Abstract
Fused silica optical elements are widely used in large high-power laser devices, and the subsurface defects of optical elements directly affect the laser damage threshold and imaging quality. These defects are distributed within a few to tens of microns from the surface and cannot be detected by conventional imaging methods. The characteristics of small size, low density and wide distribution range make it difficult to detect nondestructively, effectively and quickly with conventional methods. In order to solve the above problems, an experimental system was built based on the principles of photoluminescence and dark field scattering. Use the different characteristics of fluorescence image and scattering image to carry out the research of subsurface defect detection. First, preprocess the original image. Second, calculate the offset of adjacent images, perform background homogenization processing on the image, and stitch the sub-aperture images, and then segment the full-aperture image. Then, a more effective subsurface defect extraction algorithm is proposed. Finally, etch the sample with HF and observe it under a microscope. Experimental results show that this method can detect weak defects on the surface and sub-surface at the same time, and can effectively separate individual sub-surface defects. This method has the advantages of lossless, fast and high precision. Moreover, based on a large amount of data, analysis and summary of the causes of defects, distribution characteristics, etc.. This method can provide certain guidance for the evaluation of laser damage threshold and processing technology of optical components in high-power laser devices.
- Published
- 2021
33. Vehicle Distance Estimation Based on Monocular Vision and CNN
- Author
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Qinxiao Liu, Bo Chen, Fang Wang, Gaojian Luan, and Dongxia Hu
- Published
- 2021
34. Single image super-resolution combined with CNN and sparse representation
- Author
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Qinxiao Liu, Yongsheng Xie, Fang Wang, Chaoyuan Ding, and Dongxia Hu
- Published
- 2021
35. Multi-focus Image Fusion Algorithm Based on Unsupervised Deep Learning
- Author
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Qinxiao Liu, Gaojian Luan, Fang Wang, Bo Peng, and Dongxia Hu
- Published
- 2021
36. Design & Optimization of F-Theta Focusing Lens Based on ZEMAX
- Author
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Fang Wang, Hong Zhu, Qinxiao Liu, Dongxia Hu, and Chaoyuan Ding
- Subjects
Diffraction ,Materials science ,Aperture ,Infrared ,business.industry ,Distortion (optics) ,Physics::Optics ,Image plane ,law.invention ,Lens (optics) ,Optics ,law ,Limit (music) ,business ,Zemax - Abstract
In this paper, an optical simulation system f-theta lens composed of three ordinary glass spherical lenses is optimized by using optical design software. The lens is made of quartz glass which is commonly used in infrared band. The total length of the lens is 139mm, forming area is 85mm × 85mm. It is compact, simple and low cost. Additionally, the focal spot is very small, and the moving aperture is in a large range of 10-40mm. The focusing performance is close to the diffraction limit, and the spot size of the image plane reaches the diffraction limit of 3μm. The relative linear distortion is less than 0.005%. Therefore, our design meets the requirements of high precision for optical devices.
- Published
- 2021
37. A detection method of weak and small defects based on fluorescence imaging technology
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Liu Hongjie, Dongxia Hu, Chaoyuan Ding, Rui Dong, Fang Wang, Ye Tian, and Qinxiao Liu
- Subjects
Fluorescence-lifetime imaging microscopy ,Contrast enhancement ,Materials science ,business.industry ,media_common.quotation_subject ,Laser ,Signal ,law.invention ,Optics ,law ,Contrast (vision) ,Segmentation ,Bilateral filter ,business ,Intensity (heat transfer) ,media_common - Abstract
In large high-power laser devices,the surface and subsurface defects of fused silica optical components directly affect the laser damage threshold and imaging quality. In this paper, fluorescence imaging technology is used to obtain images of defects in the subsurface layer of optical components that will absorb laser. Because the original image has the characteristics of sparse signal, weak intensity, low contrast, etc. In order to efficiently and reliably evaluate the surface and subsurface defects, this paper proposes a weak and small defect detection method based on local adaptive contrast enhancement and seed region growth. Firstly, the local adaptive contrast enhancement method is used to enhance the contrast of the original image. Secondly, the method of bilateral filtering is used to denoise. Thirdly, seed region growth method is used to segment the defective regions and perform morphological processing. Finally, defect detection is performed. The experiment uses different segmentation methods to detect images in different regions. The results show that this method can significantly enhance the contrast of the original fluorescence image, and detect pixel-level defects, and the detection rate is stable at about 95%. Meanwhile, the reasons, size distribution and other characteristics of the sub-surface defects of fused silica optical components are analyzed. This paper provides a nondestructive method of detecting weak and small defects in the subsurface layer of the optical element faster and higher accuracy.
- Published
- 2021
38. Pork longissimus dorsi marinated with edible mushroom powders: Evaluation of quality traits, microstructure, and protein degradation
- Author
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Qingquan Fu, Haibo Shi, Dongxia Hu, Jingrong Cheng, Shoujiang Chen, and Ailing Ben
- Subjects
Red Meat ,Swine ,Papain ,Proteolysis ,Pork Meat ,Animals ,Water ,Powders ,Agaricales ,Food Science - Abstract
In this study, we examined the effects of marination with five edible mushroom powders (3%, m/m) on the quality attributes and protein changes of pork longissimus dorsi compared to meat marinated with 0.2% papain and distilled water (control group). The results indicated that pork samples marinated with edible mushrooms displayed better water retention and lower shear force, especially in the 3% Hypsizygus marmoreus (HM) group (12.50 ± 0.73 N). Ultrastructural observation results showed that the Z-disk and M-line of the pork samples marinated with edible mushrooms were fractured and weakened. Furthermore, the degradation extent of desmin in the HM-marinated pork samples was obviously increased (43%) in comparison to the papain group (only 15%), which was further confirmed by the results of the myofibril fragmentation index. Overall, the pork samples marinated with 3% HM exhibited better quality traits among all groups and might be a potential strategy to improve tenderness.
- Published
- 2022
39. Four Search Method Obtaining the Conjugating Direction Along the Negative Gradient Directions
- Author
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Chunming Li, Xiaoli Yin, and Dongxia Hu
- Subjects
Loop (topology) ,Linear programming ,Process (computing) ,Applied mathematics ,Point (geometry) ,Quadratic function ,Mathematical proof ,Rosenbrock function ,Mathematics ,Conjugate - Abstract
To find a better conjugate direction, the optimization effect of six search (six-seeking) and three search method are analyzed. Because of the arbitrariness of the initial point, the first process of optimizing along the negative gradient direction is abandoned. The four search method is put forward. Each best or optimal point is the initial point of the next optimization. After three time of consecutive searches along the negative gradient directions, take the conjugate direction obtained from the second and the third optimization as the fourth search direction. That is, there are four search directions in each loop. The steps, valid mathematical proof, and program flow chart are given. A quadratic function with three variables and Rosenbrock function with two variables are used as the objective functions to verify the methods. Two examples prove the validity of the 4 search method to complex objective function. Therefore, the four search method is a better conjugate direction method.
- Published
- 2021
40. 1178 J, 527 nm near diffraction limited laser based on a complete closed-loop adaptive optics controlled off-axis multi-pass amplification laser system
- Author
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Yang Ying, Xudong Xie, Wanguo Zheng, Lei Huang, Qihua Zhu, Xin Zhang, Xuewei Deng, Zhang Xiaomin, Feng Jing, Deen Wang, Dongxia Hu, Qiang Yuan, Wanjun Dai, Xiaofeng Wei, Zeping Yang, and Lin Chen
- Subjects
Wavefront ,Diffraction ,Nuclear and High Energy Physics ,Materials science ,business.industry ,Amplifier ,Energy conversion efficiency ,Laser ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Crystal ,Optics ,Nuclear Energy and Engineering ,law ,Laser beam quality ,business ,Adaptive optics - Abstract
A 1178 J near diffraction limited 527 nm laser is realized in a complete closed-loop adaptive optics (AO) controlled off-axis multi-pass amplification laser system. Generated from a fiber laser and amplified by the pre-amplifier and the main amplifier, a 1053 nm laser beam with the energy of 1900 J is obtained and converted into a 527 nm laser beam by a KDP crystal with 62% conversion efficiency, 1178 J and beam quality of 7.93 times the diffraction limit (DL). By using a complete closed-loop AO configuration, the static and dynamic wavefront distortions of the laser system are measured and compensated. After correction, the diameter of the circle enclosing 80% energy is improved remarkably from 7.93DL to 1.29DL. The focal spot is highly concentrated and the 1178 J, 527 nm near diffraction limited laser is achieved.
- Published
- 2021
41. Multiscale enhancement combined with local maxima for infrared filter defect detection
- Author
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Zemin Li, Qinxiao Liu, Fang Wang, Dongxia Hu, and Chaoyuan Ding
- Subjects
business.industry ,Computer science ,Gaussian ,Feature extraction ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Pattern recognition ,02 engineering and technology ,Filter (signal processing) ,Image segmentation ,01 natural sciences ,010309 optics ,Maxima and minima ,Statistical classification ,symbols.namesake ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,020201 artificial intelligence & image processing ,Segmentation ,Artificial intelligence ,business ,Infrared cut-off filter - Abstract
Due to the problems that some defects on the surface are very weak and the low contrast of the background, adaptive local contrast enhancement was adopted. Then multiscale gaussian side window filter was proposed to enhance the defect details. By looking for appropriate local maxima to locate the defect area for segmentation. The broken scratches were connected by the morphological method, then scratches and stains were classified by the geometric features parameters. By comparing and analyzing various methods of image detail enhancement and defect segmentation, the results show that the accuracy of the algorithm proposed in this paper is 91.3% in defect detection, faster than the traditional algorithms, and has higher detection efficiency and precision.
- Published
- 2020
42. Design of laser beam dump with high laser-induced-damage threshold
- Author
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Liu Hongjie, Chen Yuan, Xiang Yong, Fang Wang, Zheng Tianran, Zhufeng Shao, Ye Tian, Dongxia Hu, and Xiaodong Yuan
- Subjects
Materials science ,Geometrical optics ,business.industry ,Stray light ,Physics::Optics ,Laser ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Power (physics) ,law.invention ,Optics ,law ,Physics::Accelerator Physics ,Physics::Atomic Physics ,Beam dump ,Electrical and Electronic Engineering ,business ,Absorption (electromagnetic radiation) ,Laser beams ,Energy (signal processing) - Abstract
Laser beam dumps are necessary for laser systems designed to deliver high power or high energy to achieve effective control of stray light. However, the energy density of the stray light destroys the absorption glass of the beam dump with an increase in the output energy. To solve this problem, the initial laser-induced-damage threshold (LIDT) of a new optical absorption material was tested. A new type of laser beam dump was designed with this new optical material based on geometrical optics and light-field distribution analysis.
- Published
- 2022
43. Research on corner detection algorithm based on the long depth of field binocular camera with wavefront coding
- Author
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Rui Zhang, Qinxiao Liu, Chaoyuan Ding, Dongxia Hu, and Fang Wang
- Subjects
Point spread function ,Hessian matrix ,Computer science ,Detector ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Corner detection ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,Robustness (computer science) ,symbols ,Depth of field ,Electrical and Electronic Engineering ,Algorithm ,Camera resectioning ,Wavefront coding - Abstract
The long depth of field camera with wavefront coding is introduced in Design of Long Depth of Field Array Optical Components Defect Detection System [1]. It can obtain the whole object information at one time within 3-13 m of the depth of field. However, when binocular calibration is used in corner detection, the scalability and asymmetry of the point spread function will lead to images missing and redundancy. This article describes an improvement in the Hessian corner detector to solve this problem. Firstly, the local negative maximum with the largest change in curvature is extracted around the X corner, and the initial corner set is obtained according to their central symmetry. Then, by making use of the distance characteristics between corners of the checkerboard and constraining the angle characteristics of these corners, the false corners are filtered and the correct corner set is obtained. Finally, the corners set is sorted and the starting direction of the sorting is constrained. The corners extracted through this algorithm can be better applied to camera calibration and positioning. Experiments show that the proposed detector is better than OpenCV detector in the accuracy of positioning, calibration and measurement, and has certain robustness.
- Published
- 2022
44. Beam wavefront control of a thermal inertia laser for inertial confinement fusion application
- Author
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Wanjun, Dai, Dongxia, Hu, Wei, Zhou, Junpu, Zhao, Feng, Jing, Zeping, Yang, Kun, Zhang, Xuejun, Jiang, Wu, Deng, Runchang, Zhao, Zhitao, Peng, and Bin, Feng
- Subjects
Laser beams -- Research ,Laser fusion -- Research ,Astronomy ,Physics - Abstract
A novel scheme to correct aberration of each beam from the front-end to the target point in a thermal inertia laser (TIL) is presented. Each beam contains a deformable mirror (DM) with an aperture of 70 mm x 70 mm at the injection of the main amplifier and a Hartman--Shack (HS) sensor in a parameter diagnostic unit (PDU). A temporary HS sensor for measuring the static aberration of each beam with 1 Hz source is placed at the target point. The sensor will be removed from the target point during the main single shot, so we transfer the results measured at the target point to the sensors in the PDU. Dynamic aberration can also be measured by the HS sensor in the PDU during the single shot. In this way, we need not calibrate the aberration of the PDU, and aberration of each beam can be corrected by the DM with the HS sensor in the PDU. We demonstrate that with this scheme the divergence angle of the TIL pulses can be improved from 100 to less than 60[mu]rad with a focal length of 2200mm and beam size of 290 mm x 290 mm, which meets the requirement of a TIL. OCIS codes: 140.0140, 140.3300, 140.6810.
- Published
- 2009
45. Deformable mirror resolution-matching-based two-stage wavefront sensorless adaptive optics method
- Author
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Feng Jing, Qiang Yuan, Chuang Sun, Deen Wang, Xuewei Deng, Xin Zhang, Yang Ying, Dongxia Hu, Lei Huang, Yamin Zheng, and Wanjun Dai
- Subjects
Wavefront ,Physics ,Continuous phase modulation ,business.industry ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Deformable mirror ,Intensity (physics) ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,Spatial frequency ,Electrical and Electronic Engineering ,Adaptive optics ,Actuator ,business ,Engineering (miscellaneous) - Abstract
In high-power laser facilities, the application of a traditional wavefront control method is limited under the influence of a continuous phase plate (CPP). In order to obtain a satisfactory far-field intensity distribution at the target of the beamline with the CPP, a novel deformable mirror (DM) resolution-matching-based two-stage wavefront sensorless adaptive optics method is proposed and demonstrated. The principles of the DM resolution-matching method and two-stage wavefront sensorless adaptive optics method are introduced, respectively. Based on the numerical model, the matching relationship between the actuator space of the DM and the spatial period of the CPP is investigated. By using the resolution-matched DM, the feasibility of the two-stage wavefront sensorless adaptive optics method is numerically and experimentally verified. Both the numerical and the experimental results show that the presented DM resolution-matching-based two-stage wavefront sensorless adaptive optics method could achieve the target focal spot control under the influence of the CPP, and the profile and the intensity uniformity of the corrected focal spot are optimized close to the designed ideal focal spot.
- Published
- 2020
46. Design of long depth of field microscope lens for medium format
- Author
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Dongxia Hu, Zheng Tianran, Chaoyuan Ding, Qinxiao Liu, Fang Wang, and Liu Hongjie
- Subjects
Optics ,Microscope ,Materials science ,business.industry ,law ,Lens (geology) ,Depth of field ,business ,law.invention - Published
- 2020
47. Densification effects on porous silica: A molecular dynamics study
- Author
-
Jincheng Du, Ye Tian, Wanguo Zheng, Wei Han, and Dongxia Hu
- Subjects
010302 applied physics ,Equation of state ,Materials science ,Mechanical Engineering ,Metals and Alloys ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,law.invention ,Shock (mechanics) ,Molecular dynamics ,Molecular geometry ,Mechanics of Materials ,law ,0103 physical sciences ,General Materials Science ,Hydrostatic equilibrium ,Composite material ,0210 nano-technology ,Saturation (chemistry) ,Porosity ,Elastic modulus - Abstract
Molecular dynamics simulations are performed to investigate the effects of hydrostatic and shock densification on the structural and mechanical properties of porous silica. In the 0–35 GPa pressure range, the equation of state reveals a unique plastic-elastic transition for this material, resulting in a continuous density increase followed by saturation. Structural modifications are reflected in the medium-range order only, as evidenced by the increase of inter-tetrahedral bond angles occurring through the pressure-induced rearrangement of Si O Si planes and associated bonds. Discontinuous evolution of the elastic moduli for densified porous silica is observed and associated with the change of ring statistics.
- Published
- 2018
48. Analysis of wavefront effects for large-aperture tiled-grating compressor
- Author
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Yi Zhou, Xiaodong Wang, B. Deng, Zhang Junwei, Dongxia Hu, Shengtao Zhang, and Jingqin Su
- Subjects
Wavefront ,Physics ,Diffraction ,business.industry ,Astrophysics::Instrumentation and Methods for Astrophysics ,Holography ,Physics::Optics ,02 engineering and technology ,Grating ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Pulse (physics) ,law.invention ,010309 optics ,020210 optoelectronics & photonics ,Optics ,law ,Pulse compression ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Adaptive optics ,business ,Diffraction grating - Abstract
Monolithic large-aperture diffraction grating tiling is desired to increase the output capability of multi-kilojoule petawatt laser facilities. However, the wavefront errors of input pulse and gratings will degrade the focal spot quality and the compressibility of the output pulse. In this work, the effects of wavefront error of input pulse, deformation and wave aberration of the grating for the large-aperture tiled-grating compressor are investigated theoretically. A series of numerical simulations are presented to discuss the changing trends of focal spot energy caused by wavefront error of input pulse and obtain the error tolerance for specific goals. The influences of coating stress and the wave aberration of holographic exposure gratings on the diffraction wavefront are also discussed. Some advice is proposed for improving the performance of large-aperture tiled-grating. This work paves the way for the design of practical large-aperture tiled-grating compressor for ultrahigh intensity laser facilities in the future.
- Published
- 2018
49. Size Measurement of Laser-Induced Damage in Large-Aperture Final Optics
- Author
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Yong Xiang, Bin Feng, Fengdong Chen, Guodong Liu, Chengcheng Wang, Dongxia Hu, Qihua Zhu, Bingguo Liu, Jun Tang, Fupeng Wei, and Zhitao Peng
- Subjects
size measurement ,Accuracy and precision ,General Computer Science ,02 engineering and technology ,Size measurement ,01 natural sciences ,Measure (mathematics) ,Light scattering ,law.invention ,010309 optics ,extreme learning machine ,Optics ,law ,Approximation error ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Physics ,Total internal reflection ,business.industry ,Laser-induced damage ,General Engineering ,Laser ,inhomogeneous ,Radiometry ,020201 artificial intelligence & image processing ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,business ,lcsh:TK1-9971 - Abstract
In this paper, a hierarchical kernel extreme learning machine (HK-ELM) is proposed to solve the problem that the size of laser-induced damage (LID) cannot be accurately measured under the condition of inhomogeneous total internal reflection illumination. The proposed method overcomes the limitations of the radiometric method, which depends on a single factor to measure the size of damage. After analyzing the light scattering characteristics of LID with the finite-difference time-domain method, we find that we should consider the influences of multiple factors when measuring the size of damage under the condition of uneven illumination. The experimental results show that HK-ELM can achieve ultra-resolution measurements, and the mean relative error of the measured size predicted by HK-ELM is within 5% on the testing samples. Compared with the traditional technology, the method proposed in this paper effectively improves the measurement accuracy.
- Published
- 2018
50. Multi-feature fusion method based on WOSF and MSE for four-class MI EEG identification
- Author
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Jingjing Xie, Xiaolong Wu, Dongxia Hu, Changhui Pan, and Lingyan Hu
- Subjects
medicine.diagnostic_test ,Spatial filter ,Computer science ,business.industry ,Process (engineering) ,Interface (computing) ,Biomedical Engineering ,Health Informatics ,Pattern recognition ,Electroencephalography ,Identification (information) ,Motor imagery ,Signal Processing ,medicine ,Artificial intelligence ,business ,Neurorehabilitation ,Brain–computer interface - Abstract
Background Brain-Computer Interface (BCI) can bring great convenience to patients in the process of rehabilitation training and prosthetic control. However, how to extract effective features is a core issue in a BCI system. Methods We proposes the Multi-Feature Fusion Method based on Wavelength Optimal Spatial Filter and Multiscale Entropy for classifying the electroencephalogram signals (EEG) in four kinds of motor imagery tasks. The method can combine Wavelength features with Multiscale Entropy. Results Two groups of experiments were conducted. One for simple four types of motor imagery (MI) tasks and another for unilateral limb. Experiments show that our proposed method has better performance compared to other methods. (82.55% versus 73.08% average accuracy respectively). Conclusions The proposed method can effectively improve the accuracy of EEG classification in multiclass motor imagery and will be useful for neurorehabilitation through motor imagery for hemiplegic patients.
- Published
- 2021
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