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Structural and Ferroelectric Transition in Few-Layer HfO_(2) Films by First Principles Calculations

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Chinese Physics Letters 2024年第8期41卷 94-106页

作者： Ruiling Gao Chao Liu Bowen Shi Yongchang Li Bing Luo Rui Chen Wenbin Ouyang Heng Gao shunbo hu Yin Wang Dongdong Li Wei Ren Materials Genome Institute State Key Laboratory of Advanced Special SteelShanghai Key Laboratory of High Temperature SuperconductorsInternational Center of Quantum and Molecular StructuresPhysics DepartmentInstitute for the Conservation of Cultural HeritageShanghai UniversityShanghai 200444China Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China Shanghai World Foreign Language Academy Shanghai 200233China Key Laboratory of Silicate Cultural Relics Conservation(Ministry of Education) Shanghai UniversityShanghai 200444China Hongzhiwei Technology(Shanghai)Co. Ltd.Shanghai 201206China Zhangjiang Laboratory Shanghai 201210China

The discovery of ferroelectricity in HfO_(2)-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic ***,films structure and strain are key factors in exploration of ferroelectricity in fluorite-type oxide HfO_(2) *** we investigate the structures and straininduced ferroelectric transition in different phases of few-layer HfO_(2) films(layer number𝑁=1–5).It is found that HfO_(2) films for all phases are more stable with increasing films *** them,the Pmn2_(1)(110)-oriented film is most stable,and the films of𝑁=4,5 occur with a𝑃21 ferroelectric transition under tensile strain,resulting in polarization about 11.8μC/cm^(2) along in-plane𝑎-*** ferroelectric transition is caused by the strain,which induces the displacement of Hf and O atoms on the surface to non-centrosymmetric positions away from the original paraelectric positions,accompanied by the change of surface Hf–O bond *** importantly,three new stable HfO_(2)2D structures are discovered,together with analyses of computed electronic structures,mechanical,and dielectric *** work provides guidance for theoretical and experimental study of the new structures and strain-tuned ferroelectricity in freestanding HfO_(2) films.

关键词： properties ferroelectric positions

3DMAU-Net: liver segmentation network based on 3D U-Net

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Optoelectronics Letters 2024年

作者： Zhu Dong MA Tianyi YANG Mengzhu LI Guoqiang hu shunbo WANG Yongfang School of Information Science and Engineering， Linyi University

Accurate segmentation of the liver region using deep learning models can assist doctors in better understanding the liver's structure and pathological conditions， thereby improving the accuracy and reliability of diagnosis. Since liver CT images are 3D image data， traditional 2D neural networks are unable to capture the complete information in the 3D space， resulting in decreased segmentation accuracy. In contrast， 3D networks can better utilize spatial information to process medical image data. The 3D U-Net lacks sufficient local feature extraction for image features and lacks attention to the fusion of high and low-level features. To address the above problems， in this paper， we propose a new model called 3DMAU-Net based on the 3D U-Net network architecture. Our model replaces the last two layers of the 3D U-Net with a sliding window-based MLP， enabling better extraction of local image features. We also design a high and low-level feature fusion dilated convolution block that focuses on local features and better supplements the surrounding information of the target region. This block is embedded in the entire encoding process， ensuring that the overall network is not simply downsampling. Before each feature extraction， the input features are processed by the dilated convolution block. We validate our experiments on the Lits2017 dataset， and our model achieves a Dice coefficient of 0.95， which is an improvement of 0.015 compared to the 3D U-Net model. Furthermore， we compare our results with other segmentation methods， and our model consistently outperforms them.

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A comprehensive first-principle study of borophene-based nano gas sensor with gold electrodes

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Frontiers of physics 2022年第1期17卷 183-189页

作者： Yueyue Tian Houping Yang Junjun Li shunbo hu Shixun Cao Wei Ren Yin Wang International Centre for Quantum and Molecular Structures and Department of Physics Shanghai UniversityShanghai200444China Hongzhiwei Technology(Shanghai)Co. Ltd.Shanghai201206China Materials Genome Institute Shanghai UniversityShanghai200444China

Using density functional theory combined with nonequilibrium Green’s function method,the transport properties of borophene-based nano gas sensors with gold electrodes are calculated,and comprehensive understandings regarding the effects of gas molecules,MoS2 substrate and gold electrodes to the transport properties of borophene are *** show that borophene-based sensors can be used to detect and distinguish CO,NO,NO2 and NH3 gas molecules,MoS2 substrate leads to a nonlinear behavior on the current-voltage characteristic,and gold electrodes provide charges to borophene and form a potential barrier,which reduced the current values compared to the current of the systems without gold *** studies not only provide useful information on the computationally design of borophene-based gas sensors,but also help understand the transport behaviors and underlying physics of 2D metallic materials with metal electrodes.

关键词： quantum transport borophene gold electrodes heterostructure

Application of Opening and Closing Morphology in Deep Learning-Based Brain Image Registration

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Journal of Beijing Institute of Technology 2023年第5期32卷 609-618页

作者： Yue Yang Shiyu Liu shunbo hu Lintao Zhang Jitao Li Meng Li Fuchun Zhang School of Information Science and Engineering Linyi UniversityShandong Linyi 276000China

In order to improve the registration accuracy of brain magnetic resonance images(MRI),some deep learning registration methods use segmentation images for training ***-ever,the segmentation values are constant for each label,which leads to the gradient variation con-centrating on the ***,the dense deformation field(DDF)is gathered on the boundary and there even appears folding *** order to fully leverage the label information,the morphological opening and closing information maps are introduced to enlarge the non-zero gradi-ent regions and improve the accuracy of DDF *** opening information maps supervise the registration model to focus on smaller,narrow brain *** closing information maps supervise the registration model to pay more attention to the complex boundary ***,opening and closing morphology networks(OC_Net)are designed to automatically generate open-ing and closing information maps to realize the end-to-end training ***,a new registra-tion architecture,VM_(seg+oc),is proposed by combining OC_Net and *** results show that the registration accuracy of VM_(seg+oc) is significantly improved on LPBA40 and OASIS1 ***,VM_(seg+oc) can well improve registration accuracy in smaller brain regions and narrow regions.

关键词： three dimensional(3D)medical image registration deep learning opening operation closing operation morphology

Defect-mediated Rashba engineering for optimizing electrical transport in thermoelectric BiTeI

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npj Computational Materials 2020年第1期6卷 774-780页

作者： Xin Li Ye Sheng Lihua Wu shunbo hu Jiong Yang David J.Singh Jihui Yang Wenqing Zhang Materials Genome Institute Shanghai University99 Shangda Road200444 ShanghaiChina Materials Science and Engineering Department University of WashingtonSeattleWA 98195USA Department of Physics and Astronomy and Department of Chemistry University of MissouriColumbiaMO 65211USA Department of Physics and Shenzhen Institute for Quantum Science&Technology Southern University of Science and Technology518055 ShenzhenGuangdongChina Guangdong Provincial Key Laboratory of Computational Science and Material Design and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and Technology518055 ShenzhenGuangdongChina

The Rashba effect plays a vital role in electronic structures and related functional *** strength of the Rashba effect can be measured by the Rashba parameter α_(R);it is desirable to manipulate α_(R) to control the functional *** current work illustrates how α_(R) can be systematically tuned by doping,taking BiTeI as an example.

关键词： properties Rashba doping

Selected multiferroic perovskite oxides containing rare earth and transition metal elements

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Chinese Science Bulletin 2014年第36期59卷 5170-5179页

作者： shunbo hu Lei Chen Yabei Wu Liming Yu Xinluo Zhao Shixun Cao Jincang Zhang Wei Ren Department of Physics Shanghai University

Multiferroic materials are currently the subject of intensive research worldwide, because of both their fundamental scientific problems and also possible technological applications. Among a number of candidates in the laboratories, compounds consisting of rare earth and transition metal perovskite oxides have very unusual structural and physical properties. In contrast to the so-called type I multiferroics, ferroelectricity may be induced by magnetic ordering or by applying external fields. In this review, the recent progress on the experimental and theoretical studies of some selected type II multiferroics is presented, with a focus on the perovskite oxides containing rare earth and transition metal elements. The rare earth orthoferrite crystals, rare earth titanate strained film, and rare earthbased superlattices are systematically reviewed to provide a broad overview on their promising electric, magnetic, and structural properties. The recent experimental advances in single-crystal growth by optical floating zone method are also presented. First-principles investigations, either supported by experimental results or awaiting for experimental verifications, are shown to offer useful guidance for the future applications of unconventional multiferroics.

关键词：钙钛矿型氧化物过渡金属元素稀土元素铁电性钙钛矿氧化物外部磁场结构特性实验室

Two-Dimensional Electron Gas in MoSi_(2)N_(4)/VSi_(2)N_(4)Heterojunction by First Principles Calculation

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Chinese Physics Letters 2022年第12期39卷 57-64页

作者： Ruiling Gao Chao Liu Le Fang Bixia Yao Wei Wu Qiling Xiao shunbo hu Yu Liu Heng Gao Shixun Cao Guangsheng Song Xiangjian Meng Xiaoshuang Chen Wei Ren Physics Department State Key Laboratory of Advanced Special SteelMaterials Genome InstituteShanghai Key Laboratory of High Temperature SuperconductorsInternational Center of Quantum and Molecular StructuresShanghai UniversityShanghai 200444China Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(Ministry of Education) Anhui University of TechnologyMaanshan 243002China State Key Laboratory of Surface Physics and Department of Physics Fudan UniversityShanghai 200433China State Key Laboratory of Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

Van der Waals(vdW)layered two-dimensional(2D)materials,which may have high carrier mobility,valley polarization,excellent mechanical properties and air stability,have been widely investigated *** explore the possibility of producing a spin-polarized two-dimensional electron gas(2DEG)in the heterojunction composed of insulators MoSi_(2)N_(4)and VSi_(2)N_(4)by using first-principles *** to the charge transfer effect,the 2DEG at the interface of the MoSi_(2)N_(4)/VSi_(2)N_(4)heterojunction is ***,for different kinds of stacking of heterojunctions,lattice strain and electric fields can effectively tune the electronic structures and lead to metal-to-semiconductor *** compressive strain or electric field parallel to c axis,the 2DEG disappears and band gap opening *** the contrary,interlayer electron transfer enforces the system to become metallic under the condition of tensile strain or electric field anti-parallel to c *** changes are mainly attributed to electronic redistribution and orbitals’*** addition,we reveal that MoSi_(2)N_(4)/VSi_(2)N_(4)lateral heterojunctions of armchair and zigzag edges exhibit different electronic properties,such as a large band gap semiconductor and a metallic *** findings provide insights into electronic band engineering of MoSi_(2)N_(4)/VSi_(2)N_(4)heterojunctions and pave the way for future spintronics applications.

关键词： heterojunction polarization metallic

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图像配准中同条件非均匀抽样原则的对比研究

计算机工程与应用 2012年第3期48卷 158-161页

作者：胡顺波临沂大学信息学院山东临沂276005

使用基于浮动图像灰度概率分布和其梯度信息的非均匀抽样方法进行图像配准时,对同灰度和同梯度像素的抽样原则会影响到抽样结果和配准过程。通过对多种图像在多抽样率下进行刚体配准实验,从函数曲面和收敛性能方面,对比分析了6种数据抽... 详细信息

使用基于浮动图像灰度概率分布和其梯度信息的非均匀抽样方法进行图像配准时,对同灰度和同梯度像素的抽样原则会影响到抽样结果和配准过程。通过对多种图像在多抽样率下进行刚体配准实验,从函数曲面和收敛性能方面,对比分析了6种数据抽样原则。实验结果表明,随机抽样原则的归一化互信息测度的收敛性能和抗噪声能力优于其他5种抽样原则。

关键词：图像配准归一化互信息非均匀随机抽样原则

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非中心对称拓扑狄拉克半金属的研究进展

上海大学学报（自然科学版） 2022年第5期28卷 768-779页

作者：高恒胡顺波任伟上海大学理学院上海200444 上海大学量子与分子结构国际研究中心上海200444

狄拉克半金属由于其新奇的电子结构和输运性质,受到了实验和理论学者广泛的关注.该拓扑材料在费米能级附近存在受对称性保护的狄拉克点,是由于固体中导带和价带的能带反转导致的.本综述介绍了中心对称拓扑狄拉克半金属,并且引入了一种... 详细信息

狄拉克半金属由于其新奇的电子结构和输运性质,受到了实验和理论学者广泛的关注.该拓扑材料在费米能级附近存在受对称性保护的狄拉克点,是由于固体中导带和价带的能带反转导致的.本综述介绍了中心对称拓扑狄拉克半金属,并且引入了一种新的三维非中心对称拓扑狄拉克半金属.通过晶体结构对称性和能带对称性分析可知,具有C或C点群的晶体可以实现非中心对称拓扑狄拉克半金属.具有C点群对称性的BiPdO晶体被理论预测为非中心对称的狄拉克半金属,并且在四重旋转轴上可以实现第二类型的拓扑狄拉克点.此外,具有C点群对称性的SrHgPb晶体和LiZnSbBi合金可以实现狄拉克点与外尔点共存的拓扑半金属,并且在LiZnSbBi合金中外尔点的出现和位置可以通过元素成分比例x调控.与中心对称拓扑狄拉克半金属相比,非中心对称拓扑狄拉克半金属由于中心反演对称性的破缺,在非线性光学和非线性霍尔输运等方面有潜在的应用.

关键词：非中心对称狄拉克半金属量子材料材料设计