AI development has brought great success to upgrading the information age.At the same time,the large-scale artificial neural network for building AI systems is thirsty for computing power,which is barely satisfied by ...AI development has brought great success to upgrading the information age.At the same time,the large-scale artificial neural network for building AI systems is thirsty for computing power,which is barely satisfied by the conventional computing hardware.In the post-Moore era,the increase in computing power brought about by the size reduction of CMOS in very large-scale integrated circuits(VLSIC)is challenging to meet the growing demand for AI computing power.To address the issue,technical approaches like neuromorphic computing attract great attention because of their feature of breaking Von-Neumann architecture,and dealing with AI algorithms much more parallelly and energy efficiently.Inspired by the human neural network architecture,neuromorphic computing hardware is brought to life based on novel artificial neurons constructed by new materials or devices.Although it is relatively difficult to deploy a training process in the neuromorphic architecture like spiking neural network(SNN),the development in this field has incubated promising technologies like in-sensor computing,which brings new opportunities for multidisciplinary research,including the field of optoelectronic materials and devices,artificial neural networks,and microelectronics integration technology.The vision chips based on the architectures could reduce unnecessary data transfer and realize fast and energy-efficient visual cognitive processing.This paper reviews firstly the architectures and algorithms of SNN,and artificial neuron devices supporting neuromorphic computing,then the recent progress of in-sensor computing vision chips,which all will promote the development of AI.展开更多
Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane...Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff constructions.The competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted pyramids.On the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.展开更多
Residents’payment is an important supplement to the government’s urban haze control costs.In this paper,Zhengzhou City and Jiaozuo City of Henan Province were taken as research objects.Through research methods such ...Residents’payment is an important supplement to the government’s urban haze control costs.In this paper,Zhengzhou City and Jiaozuo City of Henan Province were taken as research objects.Through research methods such as data mining,questionnaire survey and model construction,the residents’cognition on haze control,willingness to pay and its influencing factors were deeply studied.Main research results were as below:residents in Zhengzhou and Jiaozuo have improved their awareness and satisfaction with haze control,but the growth rate was slow.In 2014,2018 and 2021,the expected values of willingness to pay for haze control in Zhengzhou were 79.94,85.52 and 47.20 yuan/month respectively,while they were 62.17,57.77 and 46.96 yuan/month in Jiaozuo City.Residents’haze awareness had the most significant effect on the willingness to pay for haze control,and there was positive correlation(P<0.05).Residents’cognition of haze control was the most important factor affecting their willingness to pay for haze control.Residents’income level and air pollution level had a positive effect on residents’willingness to pay,while residents’confidence in the government had a weak impact on their willingness to pay.展开更多
This paper analyzed the key issues and challenges confronted in the governance of Village B in the non-epicenter area in rural areas of China during the COVID-19 pandemic.It clarified the weak points in the prevention...This paper analyzed the key issues and challenges confronted in the governance of Village B in the non-epicenter area in rural areas of China during the COVID-19 pandemic.It clarified the weak points in the prevention and control of infectious diseases in Village B.A triple emergency management mechanism of"people-materials-environment"in rural areas should be established.It came up with constructive recommendations for scientifically and effectively responding to public health emergencies in rural non-epicenter areas,which is helpful to improve the rationality,legality and scientific effectiveness of the construction of emergency response mechanisms in rural areas.展开更多
A novel thin-film lithium niobate(TFLN) electro-optic modulator is proposed and demonstrated. LiNbO_(3)-silica hybrid waveguide is adopted to maintain low optical loss for an electrode spacing as narrow as 3 μm, resu...A novel thin-film lithium niobate(TFLN) electro-optic modulator is proposed and demonstrated. LiNbO_(3)-silica hybrid waveguide is adopted to maintain low optical loss for an electrode spacing as narrow as 3 μm, resulting in a low halfwave-voltage length product of only 1.7 V·cm. Capacitively loaded traveling-wave electrodes are employed to reduce the microwave loss, while a quartz substrate is used in place of a silicon substrate to achieve velocity matching. The fabricated TFLN modulator with a 5-mm-long modulation region exhibits a half-wave voltage of 3.4 V and a merely less than 2 d B roll-off in an electro-optic response up to 67 GHz.展开更多
Laser annealing of silicon dioxide (SiO2) film formed by inductively coupled plasma enhanced chemical vapor deposition (ICPECVD)is studied for the fabrication of low loss silicon based waveguide. The influence of ...Laser annealing of silicon dioxide (SiO2) film formed by inductively coupled plasma enhanced chemical vapor deposition (ICPECVD)is studied for the fabrication of low loss silicon based waveguide. The influence of laser annealing on ICPECVD-deposited SiO2 film is investigated. The surface roughness, refractive index, and etch rate of annealed samples are compared with those of SiO2 film obtained by thermal oxidation. It is demonstrated that the performance of ICPECVD-deposited SiO2 film can be significantly improved by laser annealing. Al2O3/SIO2 waveguide has been fabricated on silicon substrate with the SiO2 lower cladding formed by ICPECVD and laser annealing process, and its propagation loss is found to be comparable with that of the waveguide with thermally oxidized lower cladding.展开更多
Quantum dots in nanowires (DINWs) are considered as important building blocks for novel nanoscale semiconductor optoelectronic devices. In this paper, pure axial heterojunction InGaN/GaN DINWs are grown by using pla...Quantum dots in nanowires (DINWs) are considered as important building blocks for novel nanoscale semiconductor optoelectronic devices. In this paper, pure axial heterojunction InGaN/GaN DINWs are grown by using plasma-assisted molecular beam epitaxy (PA-MBE) system. The InGaN quantum dots (QDs) are disk-like observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The diameter of QDs can be controlled by the growth conditions of nanowires (NWs), while the thickness of QDs can be controlled by the growth time of lnGaN. Temperature-dependent photoluminescence (TDPL) measurements demonstrate that the PL peak of DINWs with small and uniform sizes shows a general red shift with increasing temperature. However, the PL peak of D1NWs with non-uniform sizes shows an abnormal blue shift with increasing temperature, which is due to different internal quantum efficiencies of the DINWs with different sizes.展开更多
基金Project supported in part by the National Key Research and Development Program of China(Grant No.2021YFA0716400)the National Natural Science Foundation of China(Grant Nos.62225405,62150027,61974080,61991443,61975093,61927811,61875104,62175126,and 62235011)+2 种基金the Ministry of Science and Technology of China(Grant Nos.2021ZD0109900 and 2021ZD0109903)the Collaborative Innovation Center of Solid-State Lighting and Energy-Saving ElectronicsTsinghua University Initiative Scientific Research Program.
文摘AI development has brought great success to upgrading the information age.At the same time,the large-scale artificial neural network for building AI systems is thirsty for computing power,which is barely satisfied by the conventional computing hardware.In the post-Moore era,the increase in computing power brought about by the size reduction of CMOS in very large-scale integrated circuits(VLSIC)is challenging to meet the growing demand for AI computing power.To address the issue,technical approaches like neuromorphic computing attract great attention because of their feature of breaking Von-Neumann architecture,and dealing with AI algorithms much more parallelly and energy efficiently.Inspired by the human neural network architecture,neuromorphic computing hardware is brought to life based on novel artificial neurons constructed by new materials or devices.Although it is relatively difficult to deploy a training process in the neuromorphic architecture like spiking neural network(SNN),the development in this field has incubated promising technologies like in-sensor computing,which brings new opportunities for multidisciplinary research,including the field of optoelectronic materials and devices,artificial neural networks,and microelectronics integration technology.The vision chips based on the architectures could reduce unnecessary data transfer and realize fast and energy-efficient visual cognitive processing.This paper reviews firstly the architectures and algorithms of SNN,and artificial neuron devices supporting neuromorphic computing,then the recent progress of in-sensor computing vision chips,which all will promote the development of AI.
基金the National Key Research and Development Program(2021YFA0716400)the National Natural Science Foundation of China(62225405,62350002,61991443)+1 种基金the Key R&D Project of Jiangsu Province,China(BE2020004)the Collaborative Innovation Centre of Solid-State Lighting and Energy-Saving Electronics.
文摘Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff constructions.The competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted pyramids.On the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.
基金Supported by Humanities and Social Sciences Project of the Ministry of Education(21YJCZH016)。
文摘Residents’payment is an important supplement to the government’s urban haze control costs.In this paper,Zhengzhou City and Jiaozuo City of Henan Province were taken as research objects.Through research methods such as data mining,questionnaire survey and model construction,the residents’cognition on haze control,willingness to pay and its influencing factors were deeply studied.Main research results were as below:residents in Zhengzhou and Jiaozuo have improved their awareness and satisfaction with haze control,but the growth rate was slow.In 2014,2018 and 2021,the expected values of willingness to pay for haze control in Zhengzhou were 79.94,85.52 and 47.20 yuan/month respectively,while they were 62.17,57.77 and 46.96 yuan/month in Jiaozuo City.Residents’haze awareness had the most significant effect on the willingness to pay for haze control,and there was positive correlation(P<0.05).Residents’cognition of haze control was the most important factor affecting their willingness to pay for haze control.Residents’income level and air pollution level had a positive effect on residents’willingness to pay,while residents’confidence in the government had a weak impact on their willingness to pay.
基金Humanities and Social Sciences Project of the Ministry of Education"Relationship between Haze Pollution and Socio-economic Growth:Research on Three Dimensions Spatial-temporal Feature,Decoupling effect and Collaborative Governance"(21YJCZH016).
文摘This paper analyzed the key issues and challenges confronted in the governance of Village B in the non-epicenter area in rural areas of China during the COVID-19 pandemic.It clarified the weak points in the prevention and control of infectious diseases in Village B.A triple emergency management mechanism of"people-materials-environment"in rural areas should be established.It came up with constructive recommendations for scientifically and effectively responding to public health emergencies in rural non-epicenter areas,which is helpful to improve the rationality,legality and scientific effectiveness of the construction of emergency response mechanisms in rural areas.
基金supported in part by the National Key R&D Program of China(No.2018YFB2201701)National Natural Science Foundation of China(Nos.61975093,61927811,61991443,61822404,61974080,61904093,and 61875104)+1 种基金Key Lab Program of BNRist(No.BNR2019ZS01005),China Postdoctoral Science Foundation(No.2019T120090)Collaborative Innovation Centre of Solid-State Lighting and Energy-Saving Electronics。
文摘A novel thin-film lithium niobate(TFLN) electro-optic modulator is proposed and demonstrated. LiNbO_(3)-silica hybrid waveguide is adopted to maintain low optical loss for an electrode spacing as narrow as 3 μm, resulting in a low halfwave-voltage length product of only 1.7 V·cm. Capacitively loaded traveling-wave electrodes are employed to reduce the microwave loss, while a quartz substrate is used in place of a silicon substrate to achieve velocity matching. The fabricated TFLN modulator with a 5-mm-long modulation region exhibits a half-wave voltage of 3.4 V and a merely less than 2 d B roll-off in an electro-optic response up to 67 GHz.
基金This work was supported by the National Basic Research Program of China (Nos. 2012CB315605 and 2014CB340002), the National Natural Science Foundation of China (Grant Nos. 61210014,61321004, 61307024, 61574082 and 51561165012), the High Technology Researeh and Development Program of China(No. 2015AA017101), the Independent Research Program of Tsinghua University (No. 20131089364) and the Open Fund of State Key Laboratory on Integrated Optoelectronics (Nos. IOSKL2012KF08 and IOSKL2014KF09).
文摘Laser annealing of silicon dioxide (SiO2) film formed by inductively coupled plasma enhanced chemical vapor deposition (ICPECVD)is studied for the fabrication of low loss silicon based waveguide. The influence of laser annealing on ICPECVD-deposited SiO2 film is investigated. The surface roughness, refractive index, and etch rate of annealed samples are compared with those of SiO2 film obtained by thermal oxidation. It is demonstrated that the performance of ICPECVD-deposited SiO2 film can be significantly improved by laser annealing. Al2O3/SIO2 waveguide has been fabricated on silicon substrate with the SiO2 lower cladding formed by ICPECVD and laser annealing process, and its propagation loss is found to be comparable with that of the waveguide with thermally oxidized lower cladding.
基金This work was supported by the National Key Basic Research Program of China (Nos. 2015CB351900, 2011CB301902 and 2011CB301903), the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (No. 2012BAE01B03), the Science and Technology Planning Project of Guangdong Province (No. 2011A081301003), the Opened Fund of the State Key Laboratory on Integrated Optoelectronics (No. IOSKL2012KF09), the High Technology Research and Development Program of China (Nos. 2011AA03A112, 2011AA03A106 and 2011AA03A105), the National Natural Science Foundation of China (Grant Nos. 61307024, 61176015 and 61176059).
基金This work was supported by the National Basic Research Program of China (No. 2013CB632804), the National Natural Science Foundation of China (Grant Nos. 61176015, 61176059, 61210014, 61321004 and 61307024), and the High Technology Research and Development Program of China (No. 2012AA05060 I).
文摘Quantum dots in nanowires (DINWs) are considered as important building blocks for novel nanoscale semiconductor optoelectronic devices. In this paper, pure axial heterojunction InGaN/GaN DINWs are grown by using plasma-assisted molecular beam epitaxy (PA-MBE) system. The InGaN quantum dots (QDs) are disk-like observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The diameter of QDs can be controlled by the growth conditions of nanowires (NWs), while the thickness of QDs can be controlled by the growth time of lnGaN. Temperature-dependent photoluminescence (TDPL) measurements demonstrate that the PL peak of DINWs with small and uniform sizes shows a general red shift with increasing temperature. However, the PL peak of D1NWs with non-uniform sizes shows an abnormal blue shift with increasing temperature, which is due to different internal quantum efficiencies of the DINWs with different sizes.