The classification and identification of brain diseases with multimodal information have attracted increasing attention in the domain of computer-aided. Compared with traditional method which use single modal feature ...The classification and identification of brain diseases with multimodal information have attracted increasing attention in the domain of computer-aided. Compared with traditional method which use single modal feature information, multiple modal information fusion can classify and diagnose brain diseases more comprehensively and accurately in patient subjects. Existing multimodal methods require manual extraction of features or additional personal information, which consumes a lot of manual work. Furthermore, the difference between different modal images along with different manual feature extraction make it difficult for models to learn the optimal solution. In this paper, we propose a multimodal 3D convolutional neural networks framework for classification of brain disease diagnosis using MR images data and PET images data of subjects. We demonstrate the performance of the proposed approach for classification of Alzheimer’s disease (AD) versus mild cognitive impairment (MCI) and normal controls (NC) on the Alzheimer’s Disease National Initiative (ADNI) data set of 3D structural MRI brain scans and FDG-PET images. Experimental results show that the performance of the proposed method for AD vs. NC, MCI vs. NC are 93.55% and 78.92% accuracy respectively. And the accuracy of the results of AD, MCI and NC 3-classification experiments is 68.86%.展开更多
Passive vibration isolation systems have been widely applied due to their low power consumption and high reliability.Nevertheless,the design of vibration isolators is usually limited by the narrow space of installatio...Passive vibration isolation systems have been widely applied due to their low power consumption and high reliability.Nevertheless,the design of vibration isolators is usually limited by the narrow space of installation,and the requirement of heavy loads needs the high supporting stiffness that leads to the narrow isolation frequency band.To improve the vibration isolation performance of passive isolation systems for dynamic loaded equipment,a novel modular quasi-zero stiffness vibration isolator(MQZS-VI)with high linearity and integrated fluid damping is proposed.The MQZS-VI can achieve high-performance vibration isolation under a constraint mounted space,which is realized by highly integrating a novel combined magnetic negative stiffness mechanism into a damping structure:The stator magnets are integrated into the cylinder block,and the moving magnets providing negative-stiffness force also function as the piston supplying damping force simultaneously.An analytical model of the novel MQZS-VI is established and verified first.The effects of geometric parameters on the characteristics of negative stiffness and damping are then elucidated in detail based on the analytical model,and the design procedure is proposed to provide guidelines for the performance optimization of the MQZS-VI.Finally,static and dynamic experiments are conducted on the prototype.The experimental results demonstrate the proposed analytical model can be effectively utilized in the optimal design of the MQZS-VI,and the optimized MQZS-VI broadened greatly the isolation frequency band and suppressed the resonance peak simultaneously,which presented a substantial potential for application in vibration isolation for dynamic loaded equipment.展开更多
Covalent organic frameworks(COFs)with high crystallinity and flexible designability have been consid-ered as promising candidates for photocatalytic hydrogen evolution.However,the existence of unpropi-tious exciton ef...Covalent organic frameworks(COFs)with high crystallinity and flexible designability have been consid-ered as promising candidates for photocatalytic hydrogen evolution.However,the existence of unpropi-tious exciton effects in COFs leads to poor charge separation,and thus results in low photocatalytic effi-ciency.Herein,to improve the photoelectron migration efficiency,we designed a 2D/2D organic/inorganic direct Z-scheme COF-based heterojunction(TpTAP/CdS),by the in-situ growing of CdS nanosheets on the COF copolymerized via 2,4,6-tris(4-aminophenyl)-1,3,5-triazine(TAP)and 1,3,5-triformylphloroglucinol(Tp).The femtosecond transient absorption(fs-TA)decay kinetics of TpTAP-COF and TpTAP/CdS further reveal the processes of shallow electron trapping and the recombination of the free photogenerated electron-hole pairs.In particular,the transient absorption traces for TpTAP-COF and TpTAP/CdS normal-ized to the photoinduced absorption peak can effectively verify the Z-scheme charge transfer between TpTAP-COF and CdS,which could enhance the charge mobility and separation,thus reducing the pho-tocorrosion of CdS.Additionally,ultraviolet photoelectron spectroscopy(UPS),in-situ X-ray photoelec-tron spectroscopy(XPS),transient photovoltage measurements,and electron spin resonance(ESR)spec-troscopy further confirm the establishment of the internal electric field(IEF).This work demonstrates the important role of COFs in the construction of 2D/2D organic/inorganic direct Z-scheme heterojunctions and offers a new avenue to explain the criticality of dynamics of the photogenerated carriers for the construction of Z-scheme heterojunctions.展开更多
Nowadays,conjugated polymers have garnered numerous attention as a new class of organic photocatalysts due to their tunable electronic properties,low cost,excellent stability and sufficient light-absorption performanc...Nowadays,conjugated polymers have garnered numerous attention as a new class of organic photocatalysts due to their tunable electronic properties,low cost,excellent stability and sufficient light-absorption performance.In particular,pyrene-benzothiadiazole-based conjugated polymer(PBBP)has been considered to be a new type of conjugated polymers for photocatalytic H_(2)evolution.However,the poor charge separation seriously limits its practical application in H_(2)evolution.In this work,a PBBP-based polymer/CdS 2D/2D organic/inorganic S-scheme heterojunction photocatalyst with a strong internal electric field is,for the first time,prepared for efficient photo-catalytic hydrogen evolution.The pyrene-benzothiadiazole-based conjugated polymers(PBBP)are synthesized by the Suzuki-Miyaura reactions.Then,the hybrid heterojunction photocatalysts are fabricated by coupling CdS with it through the ultrasonic mixing method.As a result,the highest H_(2)-production rate of 15.83 mmolh^(-1)g^(-1)is achieved on 20%PBBP/CdS composite under visible-light irradiation,nearly 2.7 times higher than that of pure CdS.The apparent quantum efficiency(AQE)of 20%PBBP/CdS composite could reach 8.66%atλ=420 nm.The enhanced activity could be attributed to the construction of S-scheme heterojunction,which accelerates the recombination of carriers with weaker redox ability and maintains the strong reducibility of electrons in CdS.This work provides a protocol for pyrene-benzothiadiazole-based conjugated polymers to prepare S-scheme heterojunction photocatalysts based on organic/inorganic coupling.展开更多
基金the National Natural Science Foundation of China under Grant No. 61672181, No. 51679058Natural Science Foundation of Heilongjiang Province under Grant No. F2016005. We would like to thank our teacher for guiding this paper. We would also like to thank classmates for their encouragement and help.
文摘The classification and identification of brain diseases with multimodal information have attracted increasing attention in the domain of computer-aided. Compared with traditional method which use single modal feature information, multiple modal information fusion can classify and diagnose brain diseases more comprehensively and accurately in patient subjects. Existing multimodal methods require manual extraction of features or additional personal information, which consumes a lot of manual work. Furthermore, the difference between different modal images along with different manual feature extraction make it difficult for models to learn the optimal solution. In this paper, we propose a multimodal 3D convolutional neural networks framework for classification of brain disease diagnosis using MR images data and PET images data of subjects. We demonstrate the performance of the proposed approach for classification of Alzheimer’s disease (AD) versus mild cognitive impairment (MCI) and normal controls (NC) on the Alzheimer’s Disease National Initiative (ADNI) data set of 3D structural MRI brain scans and FDG-PET images. Experimental results show that the performance of the proposed method for AD vs. NC, MCI vs. NC are 93.55% and 78.92% accuracy respectively. And the accuracy of the results of AD, MCI and NC 3-classification experiments is 68.86%.
基金supported by the National Key R&D Program of China(Grant Nos.2020YFB2007300 and 2020YFB2007601)the National Natural Science Foundation of China(Grant Nos.52075193,52305107,and 52275112)+1 种基金the National Science and Technology Major Project of China(Grant No.2017ZX02101007-002)the Postdoctoral Science Foundation of China(Grant No.2022M711250).
文摘Passive vibration isolation systems have been widely applied due to their low power consumption and high reliability.Nevertheless,the design of vibration isolators is usually limited by the narrow space of installation,and the requirement of heavy loads needs the high supporting stiffness that leads to the narrow isolation frequency band.To improve the vibration isolation performance of passive isolation systems for dynamic loaded equipment,a novel modular quasi-zero stiffness vibration isolator(MQZS-VI)with high linearity and integrated fluid damping is proposed.The MQZS-VI can achieve high-performance vibration isolation under a constraint mounted space,which is realized by highly integrating a novel combined magnetic negative stiffness mechanism into a damping structure:The stator magnets are integrated into the cylinder block,and the moving magnets providing negative-stiffness force also function as the piston supplying damping force simultaneously.An analytical model of the novel MQZS-VI is established and verified first.The effects of geometric parameters on the characteristics of negative stiffness and damping are then elucidated in detail based on the analytical model,and the design procedure is proposed to provide guidelines for the performance optimization of the MQZS-VI.Finally,static and dynamic experiments are conducted on the prototype.The experimental results demonstrate the proposed analytical model can be effectively utilized in the optimal design of the MQZS-VI,and the optimized MQZS-VI broadened greatly the isolation frequency band and suppressed the resonance peak simultaneously,which presented a substantial potential for application in vibration isolation for dynamic loaded equipment.
基金X.Li thanks the National Natural Science Foundation of China(Nos.21975084,51672089)the Natural Science Foundation of Guangdong Province(No.2021A1515010075)for their support+1 种基金G.Liang thanks the Key Research and Development Plan of Hubei Province(No.2021BGE037)the Teacher Research Ability Cul-tivation Foundation of Hubei University of Arts and Science(No.2020kypytd001)for their support.
文摘Covalent organic frameworks(COFs)with high crystallinity and flexible designability have been consid-ered as promising candidates for photocatalytic hydrogen evolution.However,the existence of unpropi-tious exciton effects in COFs leads to poor charge separation,and thus results in low photocatalytic effi-ciency.Herein,to improve the photoelectron migration efficiency,we designed a 2D/2D organic/inorganic direct Z-scheme COF-based heterojunction(TpTAP/CdS),by the in-situ growing of CdS nanosheets on the COF copolymerized via 2,4,6-tris(4-aminophenyl)-1,3,5-triazine(TAP)and 1,3,5-triformylphloroglucinol(Tp).The femtosecond transient absorption(fs-TA)decay kinetics of TpTAP-COF and TpTAP/CdS further reveal the processes of shallow electron trapping and the recombination of the free photogenerated electron-hole pairs.In particular,the transient absorption traces for TpTAP-COF and TpTAP/CdS normal-ized to the photoinduced absorption peak can effectively verify the Z-scheme charge transfer between TpTAP-COF and CdS,which could enhance the charge mobility and separation,thus reducing the pho-tocorrosion of CdS.Additionally,ultraviolet photoelectron spectroscopy(UPS),in-situ X-ray photoelec-tron spectroscopy(XPS),transient photovoltage measurements,and electron spin resonance(ESR)spec-troscopy further confirm the establishment of the internal electric field(IEF).This work demonstrates the important role of COFs in the construction of 2D/2D organic/inorganic direct Z-scheme heterojunctions and offers a new avenue to explain the criticality of dynamics of the photogenerated carriers for the construction of Z-scheme heterojunctions.
基金the National Natural Science Foundation of China(21975084,51672089)Natural Science Foundation of Guangdong Province(2021A1515010075)for their support。
文摘Nowadays,conjugated polymers have garnered numerous attention as a new class of organic photocatalysts due to their tunable electronic properties,low cost,excellent stability and sufficient light-absorption performance.In particular,pyrene-benzothiadiazole-based conjugated polymer(PBBP)has been considered to be a new type of conjugated polymers for photocatalytic H_(2)evolution.However,the poor charge separation seriously limits its practical application in H_(2)evolution.In this work,a PBBP-based polymer/CdS 2D/2D organic/inorganic S-scheme heterojunction photocatalyst with a strong internal electric field is,for the first time,prepared for efficient photo-catalytic hydrogen evolution.The pyrene-benzothiadiazole-based conjugated polymers(PBBP)are synthesized by the Suzuki-Miyaura reactions.Then,the hybrid heterojunction photocatalysts are fabricated by coupling CdS with it through the ultrasonic mixing method.As a result,the highest H_(2)-production rate of 15.83 mmolh^(-1)g^(-1)is achieved on 20%PBBP/CdS composite under visible-light irradiation,nearly 2.7 times higher than that of pure CdS.The apparent quantum efficiency(AQE)of 20%PBBP/CdS composite could reach 8.66%atλ=420 nm.The enhanced activity could be attributed to the construction of S-scheme heterojunction,which accelerates the recombination of carriers with weaker redox ability and maintains the strong reducibility of electrons in CdS.This work provides a protocol for pyrene-benzothiadiazole-based conjugated polymers to prepare S-scheme heterojunction photocatalysts based on organic/inorganic coupling.