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Highly efficient and aberration-free off-plane grating spectrometer and monochromator for EUV—soft X-ray applications

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light(Science & Applications) 2024年第1期13卷 68-79页

作者： Jie li Kui li Xiaoshi Zhang Dimitar Popmintchev Hao Xu Yutong Wang ruixuan li Guangyin Zhang Jiyue Tang Jin Niu Yongjun Ma Runyu Meng Changjun Ke Jisi Qiu Yunfeng Ma Tenio Popmintchev Zhongwei Fan Aerospace Information Research Institute Chinese Academy of SciencesBeijing100094China School of Optoelectronics University of the Chinese Academy of SciencesBeijing100049China Yunnan University KunmingYunnan650500China Photonics Institute TU WienViennaA-1040Austria Yunnan Observatories Chinese Academy of SciencesKunmingYunnan650011China University of California Physics DepartmentSan DiegoLa JollaCA92093USA

We demonstrate a novel flat-field,dual-optic imaging EUV—soft X-ray spectrometer and monochromator that attains an unprecedented throughput efficiency exceeding 60%by design,along with a superb spectral resolution ofλ/Δλ>200 accomplished without employing variable line spacing gratings.Exploiting the benefits of the conical diffraction geometry,the optical system is globally optimized in multidimensional parameter space to guarantee optimal imaging performance over a broad spectral range while maintaining circular and elliptical polarization states at the first,second,and third diffraction orders.Moreover,our analysis indicates minimal temporal dispersion,with pulse broadening confined within 80 fs tail-to-tail and an FWHM value of 29 fs,which enables ultrafast spectroscopic and pump-probe studies with femtosecond accuracy.Furthermore,the spectrometer can be effortlessly transformed into a monochromator spanning the EUV—soft X-ray spectral region using a single grating with an aberration-free spatial profile.Such capability allows coherent diffractive imaging applications to be conducted with highly monochromatic light in a broad spectral range and extended to the soft X-ray region with minimal photon loss,thus facilitating state-of-the-art imaging of intricate nano-and bio-systems,with a significantly enhanced spatiotemporal resolution,down to the nanometer–femtosecond level.

关键词： chromato Highly exceeding

Efficient flexible perovskite solar cells and modules using a stable SnO_(2)-nanocrystal isopropanol dispersion

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Nano Research 2024年第4期17卷 2704-2711页

作者： Zhiwei Su Jing li ruixuan Jiang Shujie Zhang Chengkai Jin Feng Ye Bingcan Ke Mengjun Zhou Jinhui Tong Hyesung Park Fuzhi Huang Yi-Bing Cheng Tongle Bu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Material Science and Engineering Wuhan University of TechnologyWuhan 430070China Department of Materials Science and Engineering Graduate School of Semiconductor Materials and Devices EngineeringGraduate School of Carbon NeutralityLow Dimensional Carbon Materials CenterUlsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan 528200China

The outstanding advantages of lightweight and flexibility enable flexible perovskite solar cells(PSCs)to have great application potential in mobile energy devices.Due to the low cost,low-temperature processibility,and high electron mobility,SnO_(2) nanocrystals have been widely employed as the electron transport layer in flexible PSCs.To prepare high-quality SnO_(2) layers,a monodispersed nanocrystal solution is normally used.However,the SnO_(2) nanocrystals can easily aggregate,especially after long periods of storage.Herein,we develop a green and cost-effective strategy for the synthesis of high-quality SnO_(2) nanocrystals at low temperatures by introducing small molecules of glycerol,obtaining a stable and well-dispersed SnO_(2)-nanocrystal isopropanol dispersion successfully.Due to the enhanced dispersity and super wettability of this alcohol-based SnO_(2)-nanocrystal solution,large-area smooth and dense SnO_(2) films are easily deposited on the plastic conductive substrate.Furthermore,this contributes to effective charge transfer and suppressed non-radiative recombination at the interface between the SnO_(2) and perovskite layers.As a result,a greatly enhanced power conversion efficiency(PCE)of 21.8%from 19.2%is achieved for small-area flexible PSCs.A large-area 5 cm×5 cm flexible perovskite solar mini-module with a champion PCE of 16.5%and good stability is also demonstrated via this glycerol-modified SnO_(2)-nanocrystal isopropanol dispersion approach.

关键词： tin oxide isopropanol dispersion colloid stability flexible perovskite solar cells

Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown Mn Bi2Te4 thin films

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National Science Review 2024年第2期11卷 24-32页

作者： Yunhe Bai Yuanzhao li Jianli Luan ruixuan liu Wenyu Song Yang Chen Peng-Fei Ji Qinghua Zhang Fanqi Meng Bingbing Tong lin li Yuying Jiang Zongwei Gao lin Gu Jinsong Zhang Yayu Wang Qi-Kun Xue Ke He Yang Feng Xiao Feng State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Institute of Physics Chinese Academy of Sciences School of Materials Science and Engineering Tsinghua University Beijing Academy of Quantum Information Sciences Frontier Science Center for Quantum Information Hefei National Laboratory Southern University of Science and Technology

The intrinsic magnetic topological insulator MnBi2Te4provides a feasible pathway to the high-temperature quantum anomalous Hall（QAH） effect as well as various novel topological quantum phases. Although quantized transport properties have been observed in exfoliated MnBi2Te4thin flakes, it remains a big challenge to achieve molecular beam epitaxy（MBE）-grown MnBi2Te4thin films even close to the quantized regime. In this work, we report the realization of quantized anomalous Hall resistivity in MBE-grown MnBi2Te4thin films with the chemical potential tuned by both controlled in situ oxygen exposure and top gating. We find that elongated post-annealing obviously elevates the temperature to achieve quantization of the Hall resistivity, but also increases the residual longitudinal resistivity, indicating a picture of high-quality QAH puddles weakly coupled by tunnel barriers. These results help to clarify the puzzles in previous experimental studies on MnBi2Te4and to find a way out of the big difficulty in obtaining MnBi2Te4samples showing quantized transport properties.

关键词： intrinsic magnetic topological insulator quantized anomalous Hall resistivity molecular beam epitaxy quantized transport property

Sentiment analysis using deep learning approaches:an overview

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Science China(Information Sciences) 2020年第1期63卷 21-56页

作者： Olivier HABIMANA Yuhua li ruixuan li Xiwu GU Ge YU School of Computer Science and Technology Huazhong University of Science and Technology School of Computer Science and Engineering Northeastern University

Nowadays, with the increasing number of Web 2.0 tools, users generate huge amounts of data in an enormous and dynamic way. In this regard, the sentiment analysis appeared to be an important tool that allows the automation of getting insight from the user-generated data. Recently, deep learning approaches have been proposed for different sentiment analysis tasks and have achieved state-of-the-art results. Therefore, in order to help researchers to depict quickly the current progress as well as current issues to be addressed, in this paper, we review deep learning approaches that have been applied to various sentiment analysis tasks and their trends of development. This study also provides the performance analysis of different deep learning models on a particular dataset at the end of each sentiment analysis task. Toward the end, the review highlights current issues and hypothesized solutions to be taken into account in future work. Moreover, based on knowledge learned from previous studies, the future work subsection shows the suggestions that can be incorporated into new deep learning models to yield better performance. Suggestions include the use of bidirectional encoder representations from transformers(BERT), sentiment-specific word embedding models, cognition-based attention models, common sense knowledge, reinforcement learning, and generative adversarial networks.

关键词： sentiment analysis opinion mining deep learning neural network natural language processing(NLP) social network

循环分层解耦卷积和最大滤波的三维脑肿瘤图像分割

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天津大学学报（自然科学与工程技术版） 2024年第3期57卷 223-233页

作者：李锵李瑞璇刘恒忻关欣 Mohammed Jajere Adamu 天津大学微电子学院天津300072

由于脑肿瘤的大小和形状呈不规则状态,从三维磁共振图像中自动分割脑肿瘤是一项具有挑战性的任务.而目前的方法存在两个问题:基于3D建模的方法参数量较大难以训练而且全局或远距离上、下文信息的关联性不足;模型忽略局部区域细节特征使... 详细信息

由于脑肿瘤的大小和形状呈不规则状态,从三维磁共振图像中自动分割脑肿瘤是一项具有挑战性的任务.而目前的方法存在两个问题:基于3D建模的方法参数量较大难以训练而且全局或远距离上、下文信息的关联性不足;模型忽略局部区域细节特征使得分割结果边界模糊.为解决上述问题,本文提出了循环分层解耦卷积和最大滤波(recurrent hierarchical-decoupled convolution and maximum filtering,RHMF)的轻量网络实现三维脑肿瘤图像分割.该网络在特征提取阶段提出循环分层解耦卷积取代标准卷积,减少参数利用多时域的反馈信息建立全局上、下文信息关联.引入改进的多尺度策略对不同尺度下的多层次特征进行提取融合,提高网络的目标识别能力.在定位阶段做局部域细节处理,提出了最大滤波模块激活目标区域像素实现特征图的像素级定位,增强目标区域像素与其他区域像素的区别,进一步细化分割,解决边界模糊问题.在BraTS2020数据集上的实验结果表明,RHMF-Net在增强肿瘤区、整体肿瘤区和核心肿瘤区的平均Dice系数值分别为77.23%、90.01%和83.10%,参数量为0.42×106.

关键词：脑肿瘤分割循环卷积轻量级注意力机制多尺度

A Novel Hybrid Method to Analyze Security Vulnerabilities in Android Applications

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Tsinghua Science and Technology 2020年第5期25卷 589-603页

作者： Junwei Tang ruixuan li Kaipeng Wang Xiwu Gu Zhiyong Xu School of Computer Science and Technology Huazhong University of Science and TechnologyWuhan 430074China Math and Computer Science Department Suffolk UniversityBostonMA 02101USA and also with Shenzhen Institute of Advanced TechnologyChinese Academy of ScienceShenzhen 518055China

We propose a novel hybrid method to analyze the security vulnerabilities in Android applications.Our method combines static analysis,which consists of metadata and data flow analyses with dynamic analysis,which includes dynamic executable scripts and application program interface hooks.Our hybrid method can effectively analyze nine major categories of important security vulnerabilities in Android applications.We design dynamic executable scripts that record and perform manual operations to customize the execution path of the target application.Our dynamic executable scripts can replace most manual operations,simplify the analysis process,and further verify the corresponding security vulnerabilities.We successfully statically analyze 5547 malwares in Drebin and 10 151real-world applications.The average analysis time of each application in Drebin is 4.52 s,whereas it reaches 92.02 s for real-word applications.Our system can detect all the labeled vulnerabilities among 56 labeled applications.Further dynamic verification shows that our static analysis accuracy approximates 95%for real-world applications.Experiments show that our dynamic analysis can effectively detect the vulnerability named input unverified,which is difficult to be detected by other methods.In addition,our dynamic analysis can be extended to detect more types of vulnerabilities.

关键词： Android security vulnerability analysis static analysis dynamic analysis

Type-2 fuzzy description logic

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Frontiers of Computer Science 2011年第2期5卷 205-215页

作者： ruixuan li Kunmei WEN Xiwu GU Yuhua li Xiaolin SUN Bing li Intelligent and Distributed Computing Laboratory School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China State Key Laboratory of Software Engineering Wuhan University Wuhan 430072 China

Description logics （DLs） are widely employed in recent semantic web application systems. However, classical description logics are limited when dealing with imprecise concepts and roles, thus providing the motivation for this work. In this paper, we present a type-2 fuzzy attributive concept language with complements （ALC） and provide its knowledge representation and reasoning algorithms. We also propose type-2 fuzzy web ontology language （OWL） to build a fuzzy ontology based on type- 2 fuzzy ALC and analyze the soundness, completeness, and complexity of the reasoning algorithms. Compared to type-1 fuzzy ALC, type-2 fuzzy ALC can describe imprecise knowledge more meticulously by using the membership degree interval. We implement a semantic search engine based on type-2 fuzzy ALC and carry out experiments on real data to test its performance. The results show that the type-2 fuzzy ALC can improve the precision and increase the number of relevant hits for imprecise information searches.

关键词： description logic （DL） type-2 fuzzy attributive concept language with complements （ALC） fuzzy ontology reasoning semantic search engine

智能区块链助力绿色金融发展:基于缓解“漂绿”困局的视角

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金融理论与实践 2024年第1期 55-65页

作者：陈睿轩李善良苏州大学政治与公共管理学院江苏苏州215123

绿色金融是帮助企业进行绿色创新的重要手段,但在实践中也存在一些“漂绿”行为。在传统绿色信贷模式下,可能由于信息不对称或代理冲突,金融机构和企业之间存在着委托代理问题,难以实现互信。基于此,提出一种基于智能区块链的数字化绿... 详细信息

绿色金融是帮助企业进行绿色创新的重要手段,但在实践中也存在一些“漂绿”行为。在传统绿色信贷模式下,可能由于信息不对称或代理冲突,金融机构和企业之间存在着委托代理问题,难以实现互信。基于此,提出一种基于智能区块链的数字化绿色信贷,来化解“信息孤岛”效应,并构建了传统绿色信贷和数字化绿色信贷两个演化博弈模型来探究智能区块链对于绿色信贷的影响。研究表明:(1)企业“漂绿”行为是影响绿色金融健康发展的重要因素;(2)智能区块链通过降低信息不对称和建立声誉机制,可以有效缓解“漂绿”困局。研究结论丰富了“漂绿”行为的理论依据并为绿色金融的可持续发展提供了思路借鉴。

关键词：绿色创新绿色信贷 “漂绿” 智能区块链演化博弈委托代理理论

Erratum to:Efficient flexible perovskite solar cells and modules using a stable SnO_(2)-nanocrystal isopropanol dispersion

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Nano Research 2024年第5期17卷 4641-4642页

作者： Zhiwei Su Jing li ruixuan Jiang Shujie Zhang Chengkai Jin Feng Ye Bingcan Ke Mengjun Zhou Jinhui Tong Hyesung Park Fuzhi Huang Yi-Bing Cheng Tongle Bu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Material Science and Engineering Wuhan University of TechnologyWuhan 430070China Department of Materials Science and Engineering Graduate School of Semiconductor Materials and Devices EngineeringGraduate School of Carbon NerutralityLow Dimensional Carbon Materials CenterUlsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratry Foshan 528200China

Erratum to Nano Research,2024,17(4):2704-2711 https://***/10.1007/s12274-023-6115-y(1)In the article,the table of contents(TOC)image was unfortunately mispresented.

关键词： perovskite dispersion modules