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Parking detection method using quadtree decomposition analysis

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第4期9卷 645-653页

作者： Khaled Shaaban Houweida Tounsi Department of Engineering Utah Valley UniversityOremUT 84058USA Blizzard Entertainment San DiegoCA 90405USA

Searching for available parking spaces can be a painful experience for drivers due to driving around until finding a vacant *** study proposes a new method to automatically detect available parking *** proposed system identifies empty parking spaces using grayscale images obtained from any type of video *** method was found to successfully identify parking availability under different conditions and *** method was tested using real-life data and achieved a detection rate of 99.7%.This method can be applied in real-time to monitor parking availability and guide drivers to empty *** method has several advantages,including simple algorithms,the use of low-quality black and white images,and simple ***,the system can provide enormous cost savings for locations with existing black and white surveillance cameras instead of replacing existing cameras with new high-quality cameras.

关键词： Traffic engineering Parking detection Smart cities Outdoor parking Image processing Image detection

Proposal for valleytronic materials:Ferrovalley metal and valley gapless semiconductor

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Frontiers of physics 2024年第2期19卷 131-139页

作者： San-Dong Guo Yu-Ling Tao Guangzhao Wang Shaobo Chen Dong Huang Yee Sin Ang School of Electronic Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology of Chongqing School of Electronic Information EngineeringYangtze Normal UniversityChongqing 408100China College of Electronic and Information Engineering Anshun UniversityAnshun 561000China Science Mathematics and Technology(SMT)Singapore University of Technology and Design(SUTD)8 Somapah RoadSingapore 487372Singapore

valleytronic materials can provide new degrees of freedom to future electronic *** this work,the concepts of the ferrovalley metal(FVM)and valley gapless semiconductor(VGS)are proposed,which can be achieved in valleytronic bilayer systems by electric field *** valleytronic bilayer systems,the interaction between out-of-plane ferroelectricity and A-type antiferromagnetism can induce layer-polarized anomalous valley Hall(LP-AVH)*** K and−K valleys of FVM are both metallic,and electron and hole carriers simultaneously *** the extreme case,the FVM can become VGS by analogizing spin gapless semiconductor(SGS).Moreover,it is proposed that the valley splitting enhancement and valley polarization reversal can be achieved by electric field engineering in valleytronic bilayer *** the bilayer RuBr_(2)as an example,our proposal is confirmed by the first-principle *** FVM and VGS can be achieved in bilayer RuBr_(2)by applying electric *** appropriate electric field range,increasing electric field can enhance valley splitting,and the valley polarization can be reversed by flipping electric field *** effectively tune valley properties by electric field in bilayer systems,the parent monolayer should possess out-of-plane magnetization,and have large valley *** results shed light on the possible role of electric field in tuning valleytronic bilayer systems,and provide a way to design the ferrovalley-related material by electric field.

关键词： valleytronics electric field bilayer

Background-free detection of molecular chirality using a single-color beam [Invited]

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Chinese Optics Letters 2022年第10期20卷 14-19页

作者：陈宇航祝晓松兰鹏飞陆培祥 Wuhan National Laboratory for Optoelectronics and School of Physics Huazhong University of Science and TechnologyWuhan 430074China Optics valley Laboratory Wuhan 430074China

We propose and numerically demonstrate a simple and background-free all-optical chiral spectroscopy technique for gas *** approach is based on high harmonic generation driven by a new type of laser beam that is produced by one linearly polarized single-color beam passing through a lens and a *** is shown that chiral and achiral signals are completely separated in frequency,indicating strong background-free and highly sensitive chirality *** believe this all-optical method can open new opportunities for ultrafast detection for chiral dynamics in the femtoseond to attosecond time scale.

关键词： high harmonic generation strong-field chiral spectroscopy selection rule

Tailoring light on three-dimensional photonic chips: a platform for versatile OAM mode optical interconnects

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Advanced Photonics 2023年第3期5卷 118-126页

作者： Jue Wang Chengkun Cai Feng Cui Min Yang Yize Liang Jian Wang Huazhong university of Science and Technology Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic InformationWuhanChina Optics valley Laboratory WuhanChina

Explosive growth in demand for data traffic has prompted exploration of the spatial dimension of lightwaves, which provides a degree of freedom to expand data transmission capacity. Various techniques basedon bulky optical devices have been proposed to tailor light waves in the spatial dimension. However, theirinherent large size, extra loss, and precise alignment requirements make these techniques relativelydifficult to implement in a compact and flexible way. In contrast, three-dimensional (3D) photonic chips withcompact size and low loss provide a promising miniaturized candidate for tailoring light in the spatialdimension. Significantly, they are attractive for chip-assisted short-distance spatial mode optical interconnectsthat are challenging to bulky optics. Here, we propose and fabricate femtosecond laser-inscribed 3D photonicchips to tailor orbital angular momentum (OAM) modes in the spatial dimension. Various functions on theplatform of 3D photonic chips are experimentally demonstrated, including the generation, (de)multiplexing,and exchange of OAM modes. Moreover, chip-chip and chip–fiber–chip short-distance optical interconnectsusing OAM modes are demonstrated in the experiment with favorable performance. This work paves the wayto flexibly tailor light waves on 3D photonic chips and offers a compact solution for versatile opticalinterconnects and other emerging applications with spatial modes.

关键词： orbital angular momentum three-dimensional photonic chips femtosecond laser writing spatial modes chip-chip chip-fiber-chip optical interconnects

Bounds for Average toward the Resonance Barrier for GL(3)×GL(2)Automorphic Forms

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数学学报:英文版 2023年第9期39卷 1667-1683页

作者： Huan Qin Yang Bo Ye San Diego State university—Imperial valley CalexicoCA92231USA Department of Mathematics The University of IowaIowa CityIowa52242-1419USA

Let f be a fixed Maass form for SL_3(Z)with Fourier coefficients A_(f)(m,n).Let g be a Maass cusp form for SL_2(G)with Laplace eigenvalue(1/4)+k^(2) and Fourier coefficientλ_(g)(n),or a holomorphic cusp form of even weight *** by S_(X)(f×g,α,β)a smoothly weighted sum of A_(f)(1,n)λ_(g)(n)e(αn~β)for X 0 are fixed real *** subject matter of the present paper is to prove non-trivial bounds for a sum of S_(X)(f×g,α,β)over g as k tends to∞with *** bounds for average provide insight for the corresponding resonance barriers toward the Hypothesis S as proposed by Iwaniec,Luo,and Sarnak.

关键词： Maass cusp form holomorphic cusp form Hypothesis S resonance barrier Kuznetsov trace formula Petersson's formula Voronoi's summation formula

Sex and stress modulate pupal defense response in tobacco hornworm

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Current Zoology 2023年第5期69卷 592-599页

作者： Sukhman Singh Sakshi Watts Ishveen Kaur Isabella Rodriguez Jessica Ayala Dariela Rodriguez Elian Martin Rupesh Kariyat Department of Entomology The Pennsylvania State UniversityState CollegePA 16802USA Department of Biology The University of Texas Rio Grande ValleyEdinburgTX 78539USA School of Earth Environmental and Marine Sciences The University of Texas Rio Grande ValleyEdinburgTX 78539USA Department of Entomology and Plant Pathology University of ArkansasFayettevilleAR 72701USA

In insects,larval and adult defenses against predators have been well ***,pupal(also known as resting stage)defenses have been overlooked and not examined *** some pupa possess antipredator strategies such as hairs,spines,cryptic coloration,and exudation of chemicals,few studies have tested these responses and the factors affecting ***,we investigated the behavioral responses in tobacco hornworm Manduca sexta that pupates in soil by introducing an external stimulus using vibrations from an electric toothbrush to mimic *** observed that *** made violent wriggling(twitching),followed by pulsating movements in response to the vibrational *** examination showed that these twitches and pulsating events occurred more frequently and for longer periods of time in male pupa and were dependent on the magnitude of the stress(high and low frequency).However,when we estimated the angular force exerted by pupa using radian and angular momentum of twitches,it was found to be independent of pupal sex.A follow-up experiment on possible cascading effects of stress exposure on eclosion success revealed that low-and high-frequency stress exposure didn’t cause any of the common defects in eclosed *** study clearly demonstrates that the so-called defenseless pupal stage uses a wide range of measurable defense behaviors that can actively defend against predators and should be examined further-linking observed behavior with underlying mechanisms.

关键词： hornworm predation pupal defenses pupal sex twitching

Simultaneous ultraviolet,visible,and near-infrared continuous-wave lasing in a rare-earth-doped microcavity

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Advanced Photonics 2022年第4期4卷 38-45页

作者： Bo Jiang Song Zhu Linhao Ren Lei Shi Xinliang Zhang Huazhong university of Science and Technology Wuhan National Laboratory for OptoelectronicsWuhanChina Nanyang Technological university School of Electrical and Electronic EngineeringSingapore Optics valley Laboratory WuhanChina

Microlaser with multiple lasing bands is critical in various applications,such as full-color display,optical communications,and ***,we propose a simple and efficient method for homogeneously doping rare earth elements into a silica whispering-gallery *** this method,an Er-Yb co-doped silica microsphere cavity with the highest quality(Q)factor(exceeding 108)among the rare-earth-doped microcavities is fabricated to demonstrate simultaneous and stable lasing covering ultraviolet,visible,and near-infrared bands under room temperature and a continuous-wave *** thresholds of all the lasing bands are estimated to be at the submilliwatt level,where both the ultraviolet and violet continuous wave upconversion lasing from rare earth elements has not been separately demonstrated under room temperature until this *** ultrahigh-Q doped microcavity is an excellent platform for highperformance multiband microlasers,ultrahigh-precision sensors,optical memories,and cavity-enhanced light–matter interaction studies.

关键词： multiband microlasers whispering-gallery microcavities rare earth elements upconversion

Advanced Mueller matrix ellipsometry:Instrumentation and emerging applications

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Science China(Technological Sciences) 2022年第9期65卷 2007-2030页

作者： CHEN XiuGuo GU HongGang LIU JiaMin CHEN Chao LIU ShiYuan State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Optics valley Laboratory Wuhan 430074China

Mueller matrix ellipsometry(MME)provides the 4×4 Mueller matrix of a sample under test,which determines how the state of polarization is changed as light interacts with the *** to the redundant information contained in the Mueller matrix,MME has gained more and more extensive applications in the characterization of surfaces,interfaces,thin films,and *** addition,the instrumentation of MME has also achieved great developments since its advent in the 1970 *** this paper,we will first review the basic principle as well as the common system layouts of MME for the full Mueller matrix ***,the basic procedure of ellipsometry data analysis is *** that,some new developments in MME in our lab for different applications are introduced,including the broadband MME,the high-resolution imaging MME,and the high-speed *** emerging applications of the developed MMEs are also *** and perspectives of the advanced ellipsometry are finally drawn and discussed.

关键词： ellipsometry Mueller matrix Mueller matrix ellipsometry imaging ellipsometry high-speed ellipsometry

Robust enhancement of valley polarization and quantum yield in composition grading lateral heterostructure of MoS2-WS2 monolayer

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Progress in Natural Science:Materials International 2024年第1期34卷 187-193页

作者： Mengke Kang Cheng Zhang Congpu Mu Kun Zhai Tianyu Xue Bochong Wang Fusheng Wen Yingchun Cheng Jianyong Xiang Jun-Feng Dai Anmin Nie Zhongyuan Liu Center for High Pressure Science State Key Laboratory of Metastable Materials Science and Technology Yanshan University Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology Shenzhen Key Laboratory of Quantum Science and Engineering

valley degeneracy can be broken owing to the strong spin-orbit coupling in two-dimensional transition metal dichalcogenides（2D-TMDCs）. valley-dependent interaction of carriers in TMDCs with different circular polarizations of light offers valley degree-of-freedom besides charge and spin to carry information. Thus, bandgap engineering of 2D-TMDCs plays a critical role in developing practical valleytronic devices. Hereby, we demonstrate a great enhancement in quantum yield as well as polarization of monolayer MoS2achieved by gradually alloying W atoms in MoS2. By appropriately setting a time offset between the evaporation of MoO3and WO3precursors during chemical vapor deposition, a compositionally graded heterostructure of MoS2-WS2monolayer can be readily grown at large scale. Raman and transmission electron microscopy measurements demonstrate that the interface possesses a steep gradient in composition, spanning from MoS2to WS2over a length ～2 μ*** to pure monolayer MoS2, the photoluminescence intensity at the compositionally graded interface of Mo1-xWxS2was observed to increase by a factor of 16 owing to the effective separation of photogenerated carriers by the built-in electric field. Particularly, a remarkably high polarization of 70% at 16 K is demonstrated for the compositionally graded interface of Mo1-xWxS2, which is ～1.4 times larger than that in MoS2and is attributed to the combined effect of the alloyed structure and graded bandgap. Such an engineering scheme with a graded bandgap offers new approach for the development of high-efficiency valleytronics devices.

关键词： Transition metal dichalcognide monolayer Compositionally graded in-plane heterostructure Chemical vapor deposition valley polarization Quantum yield