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High-performance terahertz modulators induced by substrate field in Te-based all-2D heterojunctions

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Light(Science & Applications) 2024年第3期13卷 577-586页

作者： Pujing Zhang qihang Liang Qingli Zhou Jinyu chen Menglei Li Yuwang Deng Wanlin Liang Liangliang Zhang Qinghua Zhang Lin Gu chen Ge Kui-juan Jin Cunlin Zhang Guozhen Yang Department of Physics Key Laboratory of Terahertz OptoelectronicsMinistry of Educationand Beijing Advanced Innovation Center for Imaging Theory and TechnologyCapital Normal UniversityBeijing 100048China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Department of Materials Science and Engineering Beijing National Center for Electron Microscopy and Laboratory of Advanced MaterialsTsinghua UniversityBeijing 100084China

High-performance active terahertz modulators as the indispensable core components are of great importance for the next generation communication technology.However,they currently suffer from the tradeoff between modulation depth and speed.Here,we introduce two-dimensional(2D)tellurium(Te)nanofilms with the unique structure as a new class of optically controlled terahertz modulators and demonstrate their integrated heterojunctions can successfully improve the device performances to the optimal and applicable levels among the existing all-2D broadband modulators.Further photoresponse measurements confirm the significant impact of the stacking order.We first clarify the direction of the substrate-induced electric field through first-principles calculations and uncover the unusual interaction mechanism in the photoexcited carrier dynamics associated with the charge transfer and interlayer exciton recombination.This advances the fundamental and applicative research of Te nanomaterials in high-performance terahertz optoelectronics.

关键词： performance field terahertz

On the topological surface states of the intrinsic magnetic topological insulator Mn-Bi-Te family

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National Science Review 2024年第2期11卷 50-64页

作者： Yuan Wang Xiao-Ming Ma Zhanyang Hao Yongqing Cai Hongtao Rong Fayuan Zhang Weizhao chen chengcheng Zhang Junhao Lin Yue Zhao Chang Liu qihang Liu Chaoyu chen Shenzhen Institute for Quantum Science and Engineering(SIQSE)and Department of Physics Southern University of Science and Technology(SUSTech)

We review recent progress in the electronic structure study of intrinsic magnetic topological insulators（MnBi2Te4）·（Bi2Te3）n（n = 0, 1, 2, 3） family. Specifically, we focus on the ubiquitously（nearly）gapless behavior of the topological Dirac surface state observed by photoemission spectroscopy, even though a large Dirac gap is expected because of surface ferromagnetic order. The dichotomy between experiment and theory concerning this gap behavior is perhaps the most critical and puzzling question in this frontier. We discuss various proposals accounting for the lack of magnetic effect on the topological Dirac surface state, which are mainly categorized into two pictures, magnetic reconfiguration and topological surface state redistribution. Band engineering towards opening a magnetic gap of topological surface states provides great opportunities to realize quantized topological transport and axion electrodynamics at higher temperatures.

关键词： intrinsic magnetic topological insulator topological surface states magnetic gap magnetic reconfiguration topological surface state redistribution van der Waals spacing expansion

Lycium barbarum glycopeptide(wolfberry extract)slows N-methyl-N-nitrosourea-induced degradation of photoreceptors

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Neural Regeneration Research 2024年第10期19卷 2290-2298页

作者： qihang Kong Xiu Han Haiyang cheng Jiayu Liu Huijun Zhang Tangrong Dong Jiansu chen Kwok-Fai So Xuesong Mi Ying Xu Shibo Tang Department of Ophthalmology Aier Eye HospitalJinan UniversityGuangzhouGuangdong ProvinceChina Department of Ophthalmology The First Affiliated Hospital of Jinan UniversityGuangzhouGuangdong ProvinceChina Guangdong-Hong Kong-Macao Institute of CNS Regeneration Key Laboratory of CNS Regeneration(Ministry of Education)Jinan UniversityGuangzhouGuangdong ProvinceChina Department of Ophthalmology Guangzhou Panyu Central HospitalGuangzhouGuangdong ProvinceChina School of Stomatology Jinan UniversityGuangzhouGuangdong ProvinceChina Aier Academician Station ChangshaHunan ProvinceChina Co-Innovation Center of Neuroregeneration Nantong UniversityNantongJiangsu ProvinceChina State Key Laboratory of Brain and Cognitive Sciences Hong Kong Special Administrative RegionChina

Photoreceptor cell degeneration leads to blindness, for which there is currently no effective treatment. Our previous studies have shown that Lycium barbarum(L. barbarum) polysaccharide(LBP) protects degenerated photoreceptors in rd1, a transgenic mouse model of retinitis pigmentosa. L. barbarum glycopeptide(Lb GP) is an immunoreactive glycoprotein extracted from LBP. In this study, we investigated the potential protective effect of Lb GP on a chemically induced photoreceptor-degenerative mouse model. Wild-type mice received the following: oral administration of Lb GP as a protective pre-treatment on days 1–7;intraperitoneal administration of 40 mg/kg N-methylN-nitrosourea to induce photoreceptor injury on day 7;and continuation of orally administered Lb GP on days 8–14. Treatment with Lb GP increased photoreceptor survival and improved the structure of photoreceptors, retinal photoresponse, and visual behaviors of mice with photoreceptor degeneration. Lb GP was also found to partially inhibit the activation of microglia in N-methyl-N-nitrosourea-injured retinas and significantly decreased the expression of two pro-inflammatory cytokines. In conclusion, Lb GP effectively slowed the rate of photoreceptor degeneration in N-methyl-N-nitrosourea-injured mice, possibly through an anti-inflammatory mechanism, and has potential as a candidate drug for the clinical treatment of photoreceptor degeneration.

关键词： anti-inflammation inherited retinal diseases Lycium barbarum glycopeptide N-methyl-N-nitrosourea opsin photoreceptor reactive gliosis retinal degeneration retinitis pigmentosa rhodopsin

Minimizing interfacial energy losses in inverted perovskite solar cells by a dipolar stereochemical 2D perovskite interface

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Journal of Energy Chemistry 2024年第3期90卷 496-503,I0011页

作者： Junjie Qian Jingjing He qihang Zhang chenyue Zhu Shilin chen Zhanpeng Wei Xuesong Leng Ziren Zhou Benben Shen Yu Peng Qiang Niu Shuang Yang Yu Hou Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China National Enterprise Technology Center Inner Mongolia Erdos Electric Power and Metallurgy Group Company LimitedOrdos 016064Inner MongoliaChina

Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic performance.Here,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium groups.The pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the film.Furthermore,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type modification.Ultimately,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.

关键词： Perovskite solar cells Dipole interlayer Stereochemistry Non-radiative recombination

Physical model test study on shear strength characteristics of slope sliding surface in Nanfen open-pit mine

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International Journal of Mining Science and Technology 2020年第3期30卷 421-429页

作者： Zhigang Tao Yu Shu Xiaojie Yang Yanyan Peng qihang chen Haijiang Zhang School of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Civil Engineering Shaoxing UniversityShaoxing 312000China Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province Shaoxing 312000China Zhejiang Collaborative Innovation Center for Prevention and Control of Mountain Geologic Hazards Shaoxing 312000China

A physical model for the footwall slope of Nanfen open-pit mine, China was established using a selfdeveloped deep geological engineering disaster model test system. A thermosensitive similar material,paraffin, was selected to simulate a weak structural plane in the slope to reproduce the landslide process.From an experimental perspective, the variation trend of shear strength parameters of weak structural plane and the mechanical support characteristics of NPR(negative Poisson’s ratio) anchor cable under the condition of a large landslide deformation and failure were examined. The results of this model test showed that slope failure has four distinct stages:(1) soil compaction stage,(2) crack generation stage,(3) crack propagation stage, and(4) sliding plane transfixion stage. According to the test results, the rock mechanics parameters of weak surface in the footwall slope of Nanfen open-pit mine were calculated.The cohesion is approximately 1.35×10~5 Pa, and the internal friction angle is approximately 6.33°.During slope failure, the NPR anchor cable experiences a large deformation but no damage occurs, indicating that the NPR anchor cable can be continuously monitored and reinforced during the deformation and failure of landslide. The stress characteristics of NPR anchor cables during the test are consistent with the monitoring results of Newtonian force at the landslide site, proving that NPR anchor cables are effective and reasonable in landslide monitoring and early warning.

关键词： Landslide Slope stability Structural plane Model test NPR anchor cable

融合柔性基础传递函数的转子系统建模方法及验证

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航空学报 2024年第3期45卷 182-192页

作者：李帅李启行谌璨方志法王维民北京化工大学高端机械装备健康监测与自愈化北京市重点实验室北京100029 北京化工大学高端压缩机及系统技术全国重点实验室北京100029

航空发动机、火箭涡轮泵等现代高端涡轮机械对性能有着极致的需求,其轻柔化的支承结构导致转子与柔性基础振动耦合特性明显,必须将其柔性支承结构纳入整体动力学分析之中。然而,柔性基础的高精度建模过程需要耗费大量时间,同时简化的基... 详细信息

航空发动机、火箭涡轮泵等现代高端涡轮机械对性能有着极致的需求,其轻柔化的支承结构导致转子与柔性基础振动耦合特性明显,必须将其柔性支承结构纳入整体动力学分析之中。然而,柔性基础的高精度建模过程需要耗费大量时间,同时简化的基础模型也难以表达其真实的动力学特性。为此,提出了融合柔性基础传递函数的转子系统动力学建模仿真方法:将实测得到的柔性基础传递函数通过状态子空间法拟合获得低维时域和频域表征的数学模型,通过支承力模型将柔性基础模型耦合到转子有限元模型之中,最终形成基于实物传递函数的混合转子动力学模型。同时,提出了柔性基础从稳态到瞬态的模型转换策略,并采用线性-非线性节点(显-隐)分离的快速瞬态数值积分方法进行求解。基于所提模型和计算方法,开展了柔性基础-转子系统的稳态、瞬态动力学数值仿真,以及稳定转速扫频激励和降速不平衡激励的振动测试试验,结果表明:实测的柔性基础振动特性,能够有效地体现在整机动力学分析之中,且考虑柔性基础特性的转子动力学模型所预测的瞬态动力学响应与试验结果更为吻合。所提方法为含复杂柔性基础的转子系统提供了行之有效的整机建模及瞬态仿真方法。

关键词：转子动力学柔性基础瞬态仿真传递函数快速瞬态数值积分

Germplasm resources and genetic breeding of Paeonia:a systematic review

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Horticulture Research 2020年第1期7卷 1369-1387页

作者： Yong Yang Miao Sun Shanshan Li qihang chen Jaime A.Teixeira da Silva Ajing Wang Xiaonan Yu Liangsheng Wang Key Laboratory of Plant Resources/Beijing Botanical Garden Institute of BotanyChinese Academy of Sciences100093 BeijingChina College of Landscape Architecture Beijing Forestry University100083 BeijingChina Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding 100083 BeijingChina National Engineering Research Center for Floriculture 100083 BeijingChina University of Chinese Academy of Sciences 100049 BeijingChina P.O.Box 7 Miki–cho post officeIkenobe 3011–2Kagawa–ken 761–0799Japan

Members of the genus Paeonia,which consists of globally renowned ornamentals and traditional medicinal plants with a rich history spanning over 1500 years,are widely distributed throughout the Northern Hemisphere.Since 1900,over 2200 new horticultural Paeonia cultivars have been created by the discovery and breeding of wild species.However,information pertaining to Paeonia breeding is considerably fragmented,with fundamental gaps in knowledge,creating a bottleneck in effective breeding strategies.This review systematically introduces Paeonia germplasm resources,including wild species and cultivars,summarizes the breeding strategy and results of each Paeonia cultivar group,and focuses on recent progress in the isolation and functional characterization of structural and regulatory genes related to important horticultural traits.Perspectives pertaining to the resource protection and utilization,breeding and industrialization of Paeonia in the future are also briefly discussed.

关键词： breeding cultivar globally

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基于干扰观测器的变刚度驱动器复合跟踪控制

武汉大学学报（工学版） 2024年第2期57卷 241-253页

作者：孙剑韬刘雅伦陈启航江明隆郭朝江汉大学智能制造学院湖北武汉430056 武汉大学动力与机械学院湖北武汉430072

变刚度驱动器(variable stiffness actuator,VSA)是发展新一代柔性机器人的核心技术之一,由于其模型存在参数不确定性和外部干扰等原因,针对其控制器的设计仍面临着挑战。为解决该问题,提出了一种基于非线性干扰观测器(nonlinear distur... 详细信息

变刚度驱动器(variable stiffness actuator,VSA)是发展新一代柔性机器人的核心技术之一,由于其模型存在参数不确定性和外部干扰等原因,针对其控制器的设计仍面临着挑战。为解决该问题,提出了一种基于非线性干扰观测器(nonlinear disturbance observer,NDOB)的复合控制方法,用于实现模型扰动下的VSA刚度与位置控制。与现有针对VSA的非线性控制方法相比,基于干扰观测器的复合跟踪控制方法的最显著优势在于引入了一种新的建模方法用于分析VSA在模型参数不确定、外部干扰和弹性形变等复杂摄动时的动力学;提出一种基于反馈线性化和NDOB的复合控制方法以提高驱动器跟踪精度、增加驱动器针对不确定因素时的鲁棒性。仿真和物理样机试验均验证了所提控制方法的有效性。

关键词：变刚度驱动器非线性干扰观测器柔性驱动器反馈线性化复合控制模型摄动

Effect of warpage on the electronic structure and optical properties of bilayer germanene

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Journal of Semiconductors 2022年第12期43卷 39-45页

作者： qihang Xiong Weifu Cen Xingtong Wu Cong chen College of Chemical Engineering Guizhou Minzu UniversityGuiyang 550025China College of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025China College of Mechanical and Electrical Engineering Guizhou Minzu UniversityGuiyang 550025China

The electronic structure and optical properties of bilayer germanene under different warpages are studied by the first-principles method of density functional theory.The effects of warpages on the electronic structure and optical properties of bilayer germanene are analyzed.The results of the electronic structure study show that the bottom of the conduction band of bilayer germanene moves to the lower energy direction with the increase of warpages at the K point,and the top of the valence band stays constant at the K point,and so the band gap decreases with the increase of warpage.When the warpage is 0.075 nm,the top of the valence band of bilayer germanene changes from K point to G point,and the bilayer germanene be-comes an indirect band gap semiconductor.This is an effective means to modulate the conversion of bilayer germanene between direct band gap semiconductor and indirect band gap semiconductor by adjusting the band structure of bilayer ger-manene effectively.The study of optical properties shows that the effect of warpage on the optical properties of bilayer ger-manene is mainly distributed in the ultraviolet and visible regions,and the warpage can effectively regulate the electronic struc-ture and optical properties of bilayer germanene.When the warpage is 0.069 nm,the first peak of dielectric function and extinc-tion coefficient is the largest,and the energy corresponding to the absorption band edge is the smallest.Therefore,the elec-tron utilization rate is the best when the warpage is 0.069 nm.

关键词： bilayer germanene warpages electronic structure optical properties first-principles