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SSRN 2024年

作者： Zhang, Kai He, Guanglu Cai, Lei Fan, Jianzhong Lin, Lili Li, Jing Wang, Chuankui School of Physics and Physical Engineering Qufu Normal University Qufu273165 China Shandong Province Key Laboratory of Medical Physics and Image Processing Technology School of Physics and Electronics Shandong Normal University Jinan250014 China

Multiple resonance (MR) type thermally activated delayed fluorescence (TADF) molecules are attracting attention for their narrowband emission, high luminescence efficiency, and high exciton utilization rate. Designing and studying these molecules has become an important direction for developing organic electroluminescent devices. Despite the significant potential in practical applications, developing long-wavelength emitting MR-TADF molecules remains a major challenge. This paper employs quantum mechanics/molecular mechanics (QM/MM) methods and the thermal vibration correlation function (TVCF) theory to study the luminescent properties of two MR-TADF molecules, asymmetric donor BNIP-tBuCz and symmetric donor BNDIP, in doped thin films. The calculations reveal that both molecules, while maintaining MR characteristics, possess small HOMO and LUMO energy gaps, enabling long-wavelength emission. Compared to BNIP-tBuCz, BNDIP has a slightly higher degree of conjugation and a greater proportion of π-π* transitions. Additionally, the transition dipole moment density and transition dipole moment in BNDIP are significantly enhanced, increasing the radiative rate. Both BNIP-tBuCz and BNDIP maintain similar porosity in thin films;however, BNIP-tBuCz is more sensitive to the aggregated environment. Stronger intermolecular interactions in BNDIP effectively suppress out-of-plane methyl wagging vibrations in low-frequency modes and C=C stretching vibrations in high-frequency modes, reducing reorganization energy and inhibiting the loss of non-radiative energy in the excited state. Furthermore, BNDIP's smaller energy gap between T1 and S1 (ΔEST) and its reorganization energy facilitate a faster reverse intersystem crossing rate (kRISC). Energy transfer characteristics are also studied using the semi-empirical Marcus theory. The calculated energy transfer rates of singlet and triplet states in BNIP-tBuCz are greater than those in BNDIP, due to the larger Gibbs free energy and excito

关键词： Energy transfer

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The Role of Bridging Groups in Regulating the Luminescence and Charge Transfer Properties of Thermally Activated Delayed Fluorescence Molecules: A Theoretical Perspective

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SSRN 2024年

作者： Zhang, Kai He, GuangLu Cai, Lei Fan, Jianzhong Lin, Lili Wang, Chuan-Kui Li, Jing School of Physics and Physical Engineering Qufu Normal University Qufu273165 China Shandong Province Key Laboratory of Medical Physics and Image Processing Technology School of Physics and Electronics Shandong Normal University Jinan250014 China

organic emitters with a simultaneous combination of aggregation-induced emission (AIE) and thermally activated delayed fluorescence (TADF) characteristics are in great demand due to their excellent comprehensive performances toward efficient organic light-emitting diodes (OLEDs), biomedical imaging, and the telecommunications field. However, the development of efficient AIE-TADF materials remains a substantial challenge. In this work, light-emitting properties of two AIE-TADF molecules with different bridging groups ICz-BP and ICz-DPS are theoretically investigated in solid state with combined quantum mechanics/molecular mechanics (QM/MM) method and the thermal vibration correlation function (TVCF) theory. The research indicates that the C=O bridging bond in ICz-BP is more favorable than the S=O bridging bond in ICz-DPS for enhancing the planarity of the acceptor, increasing conjugation, and thereby elevating the transition dipole moment density. Simultaneously, the stacking pattern of ICz-BP in the solid facilitates a reduction in energy gap between S1 and T1 (ΔEST), achieving rapid reverse intersystem crossing rate (kRISC). Furthermore, compared to the toluene, the stacking patterns of ICz-BP and ICz-DPS in the solid effectively suppress the out-of-plane wagging vibration of the acceptor, thereby inhibiting the loss of non-radiative energy in the excited state and realizing aggregation-induced emission. Moreover, the charge transport properties of both electrons and holes in ICz-BP are found to be higher than the corresponding rates in ICz-DPS, attributed to the smaller internal reorganization energy of ICz-BP in the solid state. Additionally, the calculations reveal a more balanced charge transport characteristic in ICz-BP, contributing to efficient exciton recombination and emission, ultimately mitigating efficiency roll-off. Based on these computational results, we aim to unveil the relationship between molecular structure and light-emitting properties, aiding

关键词： Excited states

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Effect of Hydrostatic Pressure on Room Temperature Phosphorescence Properties: A Theoretical Perspective

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SSRN 2024年

作者： Pang, Kunwei Xie, Zhen Lin, Lili Song, Yuzhi Wang, Chuan-Kui Fan, Jianzhong Xu, Yuanyuan Shandong Province Key Laboratory of Medical Physics and Image Processing Technology School of Physics and Electronics Shandong Normal University Jinan250014 China School of Science Qilu University of Technology Shandong Academy of Sciences Jinan250353 China

Development of stimulus-responsive RTP molecules becomes imperative. However, the inner responsive mechanism is unclear, theoretical investigations to reveal the relationship among hydrostatic pressures, molecular structures and photophysical properties are highly desired. Herein, based on the dispersion corrected density functional theory, the combined quantum mechanics and molecular dynamics method and thermal vibration correlation function theory, influences of hydrostatic pressure on molecular structures, transition properties as well as lifetimes and efficiencies of RTP molecule are theoretically studied. Results show that extended lifetime and enhanced efficiency are observed at 2 Gpa compared with molecule at normal pressure, and this is related with the small reorganization energy and large oscillator strength. Moreover, due to the small energy gap and remarkable spin-orbit coupling constant, fast intersystem crossing process is determined for molecule at 6 Gpa. Our work provides theoretical insights into the hydrostatic pressure response mechanism and could promote the development new efficient stimulus-responsive molecules. © 2024, The Authors. All rights reserved.

关键词： Hydrostatic pressure

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Direct PET Parametric Imaging Using Deep image Prior and a Parameter Amplification Strategy

Direct PET Parametric Imaging Using Deep Image Prior and a P...

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2022 IEEE Nuclear Science Symposium, Medical Imaging Conference, and Room Temperature Semiconductor Detector Conference, IEEE NSS MIC RTSD 2022

作者： Hong, Xiaotong Wang, Fanghu Lu, Lijun Southern Medical University School of Biomedical Engineering Guangdong Province Key Laboratory of Medical Image Processing Guangzhou510515 China Guangdong Provincial People's Hospital Guangdong Academy of Medical Sciences WeiLun Pet Center Department of Nuclear Medicine Guangzhou510080 China

ISBN: (纸本)9781665488723

Direct parametric imaging in positron emission tomography (PET) is the technique of reconstructing pharmacokinetic parametric images directly from raw PET data. Nonlinear parametric imaging is challenging due to the high level of noise in the raw PET data and the complex mapping from kinetic parameters to the projection space. In this work, we proposed a parameter amplification strategy and incorporated deep image prior (DIP) and forward physical model to reconstruct parametric images of nonlinear compartmental model. We used a U-Net as generator to output multiple images from different channels, and each channel output was scaled by an amplification factor (AF) to obtain the parametric image. Amplification was applied on the parameters that had small values and less impact on the objective function modeled by Poisson measured data. The proposed DIP-AF method was tested on the two-tissue model using 30-minute dynamic18F-FDG cardiac phantom data, and an AF of 10 was applied on k3. Results showed that the DIP-based method outperformed than the traditional indirect method and an optimization transfer direct method (OTEM). The reconstructed k3 and Ki images using the proposed DIP-AF method showed less noise and better image structure compared to the DIP-only method, which demonstrated the effectiveness of the parameter amplification strategy © 2022 IEEE.

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Micro-structured lepidocrocite-type H_(1.07)Ti_(1.73)O_(4)as anode for lithium-ion batteries with an ultrahigh rate and long-term cycling performance

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Rare Metals 2021年第6期40卷 1391-1401页

作者： Li-Juan Hou Rui-Chao Liu Hui-Yu Yuan De-Zhi Kong Wei-Xia Shen Jin-Hao Zang Juan Guo Shu-Ge Dai Ming-Lang Wang Ting-Ting Xu Xin-Jian Li Ye Wang Key Laboratory of Material Physics of Ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450052China Key Laboratory of Henan Province for High Temperature Functional Materials Zhengzhou 450000China Shandong Key Laboratory of Medical Physics and Image Processing&Shandong Provincial Engineering and Technical Center of Light Manipulations School of Physics and ElectronicsShandong Normal UniversityJinan 250358China

The lepidocrocite-type H_(1.07)Ti_(1.73)O_(4) microsized structures with a tap density of 0.88 g·cm^(-3) were prepared through the ion exchange method with K_(0.8)Li_(0.27)Ti_(1.73)O_(4) powder as the precursor,and they exhibited good rate performance and outstanding cycle stability as an anode material for lithium ion batteries(LIB).The ion exchange method provides favorable conditions for H_(1.07)Ti_(1.73)O_(4) as an anode electrode material for LIBs.X-ray photoelectron spectroscopy(XPS)result demonstrates the existence of defects in the nonstoichiometric H1.07Ti1.73O4,which have a beneficial effect on the LIB *** electrochemical performance test proves that the half-cell with microsized H_(1.07)Ti_(1.73)O_(4)as the anode electrode can maintain a specific capacity of 129.5 mAh·g^(-1) after 1100 cycles and 101 mAh·g^(-1)after 3000 long cycles at high current densities of 2.0 and 5.0 A·g^(-1),*** addition,the small volume change rate of 3.6%in H_(1.07)Ti_(1.73)O_(4)during Li ion insertion was confirmed by real-time in situ transmission electron microscopy(TEM).The LiFePO_(4)||H_(1.07)Ti_(1.73)O_(4)full battery exhibits a longterm cycling stability with a specific capacity of73.8 mAh·g^(-1) at a current density of 500 mA·g^(-1) after 200 cycles.

关键词： Lepidocrocite-type H_(1.07)Ti_(1.73)O_(4) Anode material of lithium ion batteries Long cycle stability

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Generation of Dual-Wavelength Q-Switched Pulses and Bright-Dark Pulses Pairs in an Erbium-Doped Fiber Laser with Nbs2 as Saturable Absorber

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SSRN 2024年

作者： Fu, Shenggui Tang, Yunqi Li, Qi Li, Shuaimeng Ye, Faming Xiong, Siyuan Wang, Lezheng He, Yutian Zhao, Ziting Wang, Guomei Zhang, Wenfei Bai, Caixun Lu, Cheng Zhang, Huanian School of Physics and Optoelectronic Engineering Shandong University of Technology Zibo255049 China Shandong Province Key Laboratory of Medical Physics and Image Processing Technology Shandong Provincial Key Laboratory of Optics and Photonic Device School of Physics and Electronics Shandong Normal University Jinan250014 China

In this experiment, stable dual-wavelength Q-switched pulses and bright-dark pulses pairs are achieved in an erbium-doped fiber laser based on NbS2 under saturable absorber. At pump powers of 172 mW~322 mW, stable dual-wavelength Q-switched pulses with center wavelengths of 1531.9 nm and 1557.05 nm were obtained with a signal-to-noise ratio (SNR) as high as 43 dB. The repetition frequency was increased from 14.3 kHz to 22.7 kHz as the increase of pump power was increased. When the pump power was increased to 340mW, we found stable bright-dark pulses with center wavelengths of 1559.7 nm and 1560.12 nm, respectively, and a repetition frequency of 3.44 MHz with an SNR of 52 dB. The experimental results show that NbS2 can be used as an excellent SA for fiber lasers and demonstrate that NbS2 can be used to study dual-wave Q-switched pulses and bright-dark soliton pairs. © 2024, The Authors. All rights reserved.

关键词： Signal to noise ratio

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Research on the Strike Strategy of Quadcopter Unmanned Aerial Vehicles for Mobile Targets

Research on the Strike Strategy of Quadcopter Unmanned Aeria...

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WRC Symposium on Advanced Robotics and Automation (WRC SARA)

作者： Wencai Zhang Junjie Sun Yanying Li Shen Yan Ning Zhang Jiaqi Wang Zhihua Chen Mingran Pan Engineering Technicians of Norinco Group Liao Shen Industries Group CO.LTD Shenyang China Key Laboratory of Jiangxi Province for Image Processing and Pattern Recognition and MOE Key Lab of Nondestructive Testing Technology Nanchang Hangkong University Nanchang China

ISBN: (数字)9798331506100

ISBN: (纸本)9798331506117

This paper studies a strike path strategy for quadcopter drones targeting ground maneuvering targets. The strategy sets the strike path to two different strike speeds, which improves the stability and robustness of quadcopter drones while shortening strike time and increasing hit rates. Consider the attitude control of quadcopter unmanned aerial vehicles during motion, and verify the flight reliability of the mechanism through simulation experiments. Set different slope strike paths and obtain the optimal strike path through experiments, while proving the effectiveness of this strike strategy in engineering applications.

关键词： Attitude control Prototypes Autonomous aerial vehicles Stability analysis Robustness Robotics and automation Aircraft propulsion

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Deep Learning Methods for Ship Classification: From Visible to Infrared images 5

Deep Learning Methods for Ship Classification: From Visible ...

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5th International Conference on Robotics, Intelligent Control and Artificial Intelligence, RICAI 2023

作者： Liu, Tianci Qin, Hengjia Zhan, Zhuo Liu, Yunpeng Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110016 China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang110169 China University of Chinese Academy of Sciences Beijing100049 China Chinese Academy of Sciences Key Laboratory of Opto-Electronic Information Processing Shenyang110016 China Key Laboratory of Image Understanding and Computer Vision Liaoning Province Shenyang110016 China The Third Military Representative Office of the Air Force Equipment Department in Shenyang Region Liaoning Province Shenyang110027 China

ISBN: (纸本)9798350357950

Deep learning methods have achieved excellent performances on visual tasks of target recognition and classification. The rapid development of autonomous seafaring vessels comes up with the requirement to recognize other maritime ships day and night. However, the recognition of ships based on the deep neural networks may not always access the results as expectation when the ships are under the nighttime environment. To this issue, we consider the ship recognition task under the deep learning framework with paired visible images and infrared images. In this article, we propose an end-to-end convolutional network based on visible images and infrared images of the autonomous seafaring vessels. To demonstrate the effectiveness of our model, we choose the V AIS dataset to test the performance of classifying the maritime ships. Experimental results show that the proposed network outperforms the state-of-the-art methods based on the V AIS database. © 2023 IEEE.

关键词： deep learning infrared images neural network Ship recognition

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UNQA: Unified No-Reference Quality Assessment for Audio, image, Video, and Audio-Visual Content

arXiv

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arXiv 2024年

作者： Cao, Yuqin Min, Xiongkuo Gao, Yixuan Sun, Wei Lin, Weisi Zhai, Guangtao The Institute of Image Communication and Network Engineering Shanghai Key Laboratory of Digital Media Processing and Transmissions Shanghai Jiao Tong University Shanghai200240 China The School of Computer Science and Engineering Nanyang Technological University Singapore639798 Singapore

As multimedia data flourishes on the Internet, quality assessment (QA) of multimedia data becomes paramount for digital media applications. Since multimedia data includes multiple modalities including audio, image, video, and audiovisual (A/V) content, researchers have developed a range of QA methods to evaluate the quality of different modality data. While they exclusively focus on addressing the single modality QA issues, a unified QA model that can handle diverse media across multiple modalities is still missing, whereas the latter can better resemble human perception behaviour and also have a wider range of applications. In this paper, we propose the Unified No-reference Quality Assessment model (UNQA) for audio, image, video, and A/V content, which tries to train a single QA model across different media modalities. To tackle the issue of inconsistent quality scales among different QA databases, we develop a multi-modality strategy to jointly train UNQA on multiple QA databases. Based on the input modality, UNQA selectively extracts the spatial features, motion features, and audio features, and calculates a final quality score via the four corresponding modality regression modules. Compared with existing QA methods, UNQA has two advantages: 1) the multi-modality training strategy makes the QA model learn more general and robust quality-aware feature representation as evidenced by the superior performance of UNQA compared to state-of-the-art QA methods. 2) UNQA reduces the number of models required to assess multimedia data across different modalities. and is friendly to deploy to practical applications. Copyright © 2024, The Authors. All rights reserved.

关键词： Audiovisual

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Boosting Medical image Synthesis via Registration-guided Consistency and Disentanglement Learning

arXiv

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arXiv 2024年

作者： Li, Chuanpu Chen, Zeli Zhang, Yiwen Zhong, Liming Yang, Wei School of Biomedical Engineering Southern Medical University Guangzhou China Guangdong Provincial Key Laboratory of Medical Image Processing Southern Medical University Guangzhou China Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology Southern Medical University Guangzhou China

Medical image synthesis remains challenging due to misalignment noise during training. Existing methods have attempted to address this challenge by incorporating a registration-guided module. However, these methods tend to overlook the task-specific constraints on the synthetic and registration modules, which may cause the synthetic module to still generate spatially aligned images with misaligned target images during training, regardless of the registration module’s function. Therefore, this paper proposes registration-guided consistency and incorporates disentanglement learning for medical image synthesis. The proposed registration-guided consistency architecture fosters task-specificity within the synthetic and registration modules by applying identical deformation fields before and after synthesis, while enforcing output consistency through an alignment loss. Moreover, the synthetic module is designed to possess the capability of disentangling anatomical structures and specific styles across various modalities. An anatomy consistency loss is introduced to further compel the synthetic module to preserve geometrical integrity within latent spaces. Experiments conducted on both an in-house abdominal CECT-CT dataset and a publicly available pelvic MR-CT dataset have demonstrated the superiority of the proposed method. Copyright © 2024, The Authors. All rights reserved.

关键词： Computerized tomography

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