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双波长视网膜成像自适应光学系统的轴向色差补偿方法

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中国光学 2022年第1期15卷 79-89页

作者：朱沁雨韩国庆彭建涛饶启龙沈毅力陈梅蕊孙会娟毛红敏徐国定曹召良宣丽苏州科技大学物理科学与技术学院江苏微纳热流技术与能源应用重点实验室江苏苏州215009 中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室长春130033 中国航天科技集团公司上海卫星工程研究所上海201109 北京联合大学基础与交叉科学研究所数学与物理研究所北京100101

双波长视网膜成像自适应光学系统非常适用于视网膜微血管的高对比度和高分辨率成像。本文重点研究了双波长自适应系统的轴向色差补偿问题。首先对轴向色差进行了测量,对实测波前进行了分析,并给出任意波前轴向色差补偿法。自适应校正实... 详细信息

双波长视网膜成像自适应光学系统非常适用于视网膜微血管的高对比度和高分辨率成像。本文重点研究了双波长自适应系统的轴向色差补偿问题。首先对轴向色差进行了测量,对实测波前进行了分析,并给出任意波前轴向色差补偿法。自适应校正实验结果显示,色差补偿后,波前均方根误差减小到0.16λ(λ=589 nm),视网膜微血管分辨率提高到6μm。这项工作可用于视网膜成像的临床应用。

关键词：自适应光学视网膜成像轴向色差双波长

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遥感卫星高精度高稳定度控制技术

上海航天 2014年第3期31卷 24-33,38页

作者：边志强蔡陈生吕旺沈毅力上海卫星工程研究所上海200240 上海航天控制技术研究所上海200233

对遥感卫星高精度高稳定度控制技术进行了综述。给出了国内外高稳定度多挠性遥感卫星控制、快速机动控制、高精度姿态确定、自主智能控制等典型应用,以及未来发展趋势。分析了挠性多体卫星结构-控制一体化设计、卫星在轨试验和高精度姿... 详细信息

对遥感卫星高精度高稳定度控制技术进行了综述。给出了国内外高稳定度多挠性遥感卫星控制、快速机动控制、高精度姿态确定、自主智能控制等典型应用,以及未来发展趋势。分析了挠性多体卫星结构-控制一体化设计、卫星在轨试验和高精度姿态确定等关键技术。讨论了挠性多体卫星动力学建模仿真及地面试验验证,H∞控制、自适应滤波前馈等卫星姿态控制方法研究与应用,卫星结构模态与无干扰力矩在轨辨识,以及基于陀螺、星敏感器及其误差、卫星动力学模型、在轨热变形标定等高精度姿态确定技术。

关键词：遥感卫星挠性多体动力学高精度高稳定度姿态控制

Research on a Monte Carlo global variance reduction method based on an automatic importance sampling method

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Nuclear Science and Techniques 2024年第5期35卷 200-215页

作者： yi-sheng Hao Zhen Wu shen-shen Gao Rui Qiu Hui Zhang Jun-li li Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging of Ministry of Education Beijing 100084China Nuctech Company limited Beijing 100084China

Global variance reduction is a bottleneck in Monte Carlo shielding *** global variance reduction problem requires that the statistical error of the entire space is *** study proposed a grid-AIS method for the global variance reduction problem based on the AIS method,which was implemented in the Monte Carlo program *** proposed method was validated using the VENUS-Ⅲ international benchmark problem and a self-shielding calculation *** results from the VENUS-Ⅲ benchmark problem showed that the grid-AIS method achieved a significant reduction in the variance of the statistical errors of the MESH grids,decreasing from 1.08×10^(-2) to 3.84×10^(-3),representing a 64.00% *** demonstrates that the grid-AIS method is effective in addressing global *** results of the selfshielding calculation demonstrate that the grid-AIS method produced accurate computational ***,the grid-AIS method exhibited a computational efficiency approximately one order of magnitude higher than that of the AIS method and approximately two orders of magnitude higher than that of the conventional Monte Carlo method.

关键词： Monte Carlo Global variance reduction Reactor shielding Automatic importance sampling

超声心动图、浅表高频超声及联合使用诊断肺动脉瓣狭窄患儿瓣膜数的价值

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中国现代医学杂志 2019年第4期29卷 104-107页

作者：李慎义张轶陈红天龙湘党刘亮危安湖南省人民医院湖南长沙410005

目的评价超声心动图联合浅表高频超声探测新生儿及小儿肺动脉瓣狭窄(PS)患儿肺动脉瓣瓣叶数目的效果。方法分别对新生儿及小儿PS患儿的肺动脉瓣进行超声心动图及浅表高频超声二维成像。结果超声心动图、浅表高频超声和超声心动图联合浅... 详细信息

目的评价超声心动图联合浅表高频超声探测新生儿及小儿肺动脉瓣狭窄(PS)患儿肺动脉瓣瓣叶数目的效果。方法分别对新生儿及小儿PS患儿的肺动脉瓣进行超声心动图及浅表高频超声二维成像。结果超声心动图、浅表高频超声和超声心动图联合浅表高频超声对明确新生儿及小儿PS患儿肺动脉瓣数目的敏感性分别为81.25%、87.50%和93.75%,特异性分别为75.00%、84.62%和92.31%,准确性分别为73.33%、83.33%和90.00%,阳性预测值为72.22%、82.35%和88.24%,阴性预测值为75.00%、84.61%和92.31%。以手术结果为金标准,超声心动图、浅表高频超声和超声心动图联合浅表高频超声为结果值,分别绘制ROC曲线,曲线下面积分别为0.728、0.830和0.897。结论超声心动图联合浅表高频超声能获得比单用心脏探头更清晰的肺动脉瓣膜二维信息,可为新生儿及小儿PS的瓣膜数目做出更准确判断,从而能为临床提供更可靠的信息。

关键词：肺动脉瓣狭窄超声心动扫描术超声检查婴儿

On the convergence and improvement of stochastic normalized gradient descent

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Science China(Information Sciences) 2021年第3期64卷 105-117页

作者： shen-yi ZHAO yin-Peng XIE Wu-Jun li National Key Laboratory for Novel Software Technology Department of Computer Science and TechnologyNanjing University

Non-convex models, like deep neural networks, have been widely used in machine learning applications. Training non-convex models is a difficult task owing to the saddle points of models. Recently,stochastic normalized gradient descent(SNGD), which updates the model parameter by a normalized gradient in each iteration, has attracted much attention. Existing results show that SNGD can achieve better performance on escaping saddle points than classical training methods like stochastic gradient descent(SGD).However, none of the existing studies has provided theoretical proof about the convergence of SNGD for non-convex problems. In this paper, we firstly prove the convergence of SNGD for non-convex ***, we prove that SNGD can achieve the same computation complexity as SGD. In addition, based on our convergence proof of SNGD, we find that SNGD needs to adopt a small constant learning rate for convergence guarantee. This makes SNGD do not perform well on training large non-convex models in practice. Hence, we propose a new method, called stagewise SNGD(S-SNGD), to improve the performance of SNGD. Different from SNGD in which a small constant learning rate is necessary for convergence guarantee,S-SNGD can adopt a large initial learning rate and reduce the learning rate by stage. The convergence of S-SNGD can also be theoretically proved for non-convex problems. Empirical results on deep neural networks show that S-SNGD achieves better performance than SNGD in terms of both training loss and test accuracy.

关键词： non-convex problems stochastic normalized gradient descent computation complexity

The Darboux Transformation for NLS-MB Equations

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Communications in Theoretical Physics 2002年第10期38卷 493-496页

作者： HE Jing-Song CHENG yi li yi-shen Department of Mathematics University of Science and Technology of China Hefei 230026 China Department of Mathematics University of Science and Technology of China Hefei 230026 China Department of Mathematics University of Science and Technology of China Hefei 230026 China

The Darboux transformations for the nonlinear Schrodinger equation and Maxwell-Bloch equations areconstructed. The one-soliton solution and periodic solution are obtained from the different "seeds".

关键词： Darboux transformation, NLS-MB equations, soliton

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基于地标的静止轨道遥感卫星测定轨技术研究

上海航天 2015年第3期32卷 42-46页

作者：罗达宋效正沈毅力张洋上海卫星工程研究所上海200240

在考虑地面站资源受限的基础上,提出了基于地标信息对静止轨道遥感卫星进行测定轨的基本原理,给出了根据地标图像和地面站测距结果进行定轨的计算模型。分析了卫星姿态确定误差、卫星及相机结构变形误差、相机空间分辨率、大气折射、地... 详细信息

在考虑地面站资源受限的基础上,提出了基于地标信息对静止轨道遥感卫星进行测定轨的基本原理,给出了根据地标图像和地面站测距结果进行定轨的计算模型。分析了卫星姿态确定误差、卫星及相机结构变形误差、相机空间分辨率、大气折射、地面站测距误差对该方法测定轨精度的影响。对地标和地面站个数多种组合以及无地面站情况进行了定轨仿真,并与自主轨道递推结果比较,结果表明:用基于地标的测定轨方法对静止轨道遥感卫星的定轨精度可达400m,并不受地面站资源限制和时间约束,多天自主定轨精度高于星上自主轨道模型递推结果。

关键词：遥感卫星地标测定轨

Small modifications of endo-functionalized cavities lead to large changes in molecular interaction in water

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Science China Chemistry 2025年第1期 369-376页

作者： Song-Meng Wang Hao Nian Yan-Fang Wang li-Shuo Zheng Yu-Tao Zheng yi-Wei Dong liping Huang Xiaoping Wang Wei Jiang liu-Pan Yang Department of Chemistry Southern University of Science and Technology School of Chemistry and Pharmaceutical Sciences State Key Laboratory for Chemistry and Molecular Engineering of Medicinal ResourcesGuangxi Normal University School of Pharmaceutical Science Hengyang Medical School University of South China

Studying molecular recognition in aqueous environments is crucial for understanding biological processes. Herein, we present a series of N-doped endo-functionalized anthracene-based cavities by introducing inward-directed pyridine units. The subtle modifications can significantly affect the binding properties of these receptors, which is similar to the mutations in biological systems. Combining theoretical calculations and molecular recognition experiments demonstrated that these “mutations” have an impact on the hydrophobicity and charge distribution of the hosts, consequently significantly influencing molecular *** is crucial for understanding the intricate mechanisms of molecular-level interactions in biological receptors.

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Can patients with mild non-neoplastic lesions diagnosed at baseline screening be safely exempt from surveillance: evidence from multicenter community-based cohorts

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Science China life Sciences 2025年第1期 263-271页

作者： Siyi He Zhiyi Zhang Guohui Song Zhenhai Wang Chunyun Dai Shipeng Yan Kun Jiang Bingbing Song He li Maomao Cao Dianqin Sun Fan Yang Xinxin Yan Shaoli Zhang yi Teng Qianru li Changfa Xia Wanqing Chen Office of Cancer Screening National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical College Department of Gastroenterology Gansu Wuwei Tumor Hospital Cixian Cancer Institute linzhou Cancer Hospital Center for Disease Control and Prevention of Sheyang County Department of Cancer Prevention and Control Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of MedicineCentral South University Luoshan Center for Disease Control and Prevention Office for Cancer Control and Research Affiliated Cancer Hospital of Harbin Medical University

Surveillance recommendations for gastric cancer（GC） in current guidelines focused on advanced precancerous lesions and were based on precise diagnosis of severity/extent of baseline lesions. We aimed to develop a less endoscopy-related equipment-dependent risk-stratification tool, and assessed whether mild-precursor-lesion patients can be safely exempt from surveillance. In the multicenter communitybased cohort, 75,051 participants receiving baseline endoscopy were enrolled during 2015–2017 and followed-up until 2021. Cumulative incidence rates（CIRs） of GC for precancerous-conditions were calculated by Kaplan-Meier method and compared by Log-rank tests. Mixedeffects Cox regression models were used to detect potential factors for progression towards GC. A risk score was calculated as counts of selected factors. An independent cohort, including 26,586 participants was used for external validation. During a median follow-up of 6.25 years, CIRs of GC were 0.302%, 0.436%, and 4.756% for normal group, non-neoplastic（atrophic gastritis/intestinal metaplasia） and neoplastic lesions（low-grade/high-grade dysplasia）, respectively(Ptrendlimited vegetable consumption, were selected for risk-stratification. High-risk patients（≥3 risk factors） with non-neoplastic lesions showed higher GC risks（adjusted HR=7.73, 95%CI: 4.29–13.92）, and their four-year CIR reached the one-year CIR of neoplastic lesions. Further categorizing non-neoplastic lesions by histological grade, both patients with moderate-to-severe lesions（aHR=3.07, 95%CI: 1.67–5.64） and high-risk patients with mild lesions（aHR=7.29, 95%CI: 3.58–14.86） showed higher risks. Consistent trends were observed in validation cohort. High-risk mild-precursor-lesion patients should receive surveillance within 3–5 years after baseline screening. Our study provides evidence on supplementing current guideline recommendations.

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