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Deep learning for joint channel estimation and feedback in massive MIMO systems

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Digital Communications and Networks 2024年第1期10卷 83-93页

作者： Jiajia Guo Tong Chen shi Jin Geoffrey Ye Li Xin Wang Xiaolin hou National Mobile Communications Research Laboratory Southeast UniversityNanjing210096China Department of Electrical and Electronic Engineering Imperial College LondonLondonSW72AZUK DOCOMO Beijing Communications Laboratories Co. LtdBeijingChina

The great potentials of massive Multiple-Input Multiple-Output(MIMO)in Frequency Division Duplex(FDD)mode can be fully exploited when the downlink Channel State Information(CSI)is available at base stations.However,the accurate CsI is difficult to obtain due to the large amount of feedback overhead caused by massive antennas.In this paper,we propose a deep learning based joint channel estimation and feedback framework,which comprehensively realizes the estimation,compression,and reconstruction of downlink channels in FDD massive MIMO systems.Two networks are constructed to perform estimation and feedback explicitly and implicitly.The explicit network adopts a multi-Signal-to-Noise-Ratios(SNRs)technique to obtain a single trained channel estimation subnet that works well with different SNRs and employs a deep residual network to reconstruct the channels,while the implicit network directly compresses pilots and sends them back to reduce network parameters.Quantization module is also designed to generate data-bearing bitstreams.Simulation results show that the two proposed networks exhibit excellent performance of reconstruction and are robust to different environments and quantization errors.

关键词： Channel estimation CSI feedback Deep learning Massive MIMO FDD

Pure quantum gradient descent algorithm and full quantum variational eigensolver

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Frontiers of physics 2024年第2期19卷 221-234页

作者： Ronghang Chen Zhou Guang Cong Guo Guanru Feng shi-Yao hou College of Physics and Electronic Engineering Center for Computational SciencesSichuan Normal UniversityChengdu 610068China Shenzhen SpinQ Technology Co. Ltd.Shenzhen 518045China DEEPROUTE.AI

Optimization problems are prevalent in various fields,and the gradient-based gradient descent algorithm is a widely adopted optimization method.However,in classical computing,computing the numerical gradient for a function with variables necessitates at least d+1 function evaluations,resulting in a computational complexity of O(d).As the number of variables increases,the classical gradient estimation methods require substantial resources,ultimately surpassing the capabilities of classical computers.Fortunately,leveraging the principles of superposition and entanglement in quantum mechanics,quantum computers can achieve genuine parallel computing,leading to exponential acceleration over classical algorithms in some cases.In this paper,we propose a novel quantum-based gradient calculation method that requires only a single oracle calculation to obtain the numerical gradient result for a multivariate function.The complexity of this algorithm is just O(1).Building upon this approach,we successfully implemented the quantum gradient descent algorithm and applied it to the variational quantum eigensolver(VQE),creating a pure quantum variational optimization algorithm.Compared with classical gradient-based optimization algorithm,this quantum optimization algorithm has remarkable complexity advantages,providing an efficient solution to optimization problems.The proposed quantum-based method shows promise in enhancing the performance of optimization algorithms,highlighting the potential of quantum computing in this field.

关键词： quantum algorithm gradient descent variational quantum algorithm

Characteristics of the HIV/AIDS Epidemic among People Aged≥50 Years in China during 2018–2021

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Biomedical and Environmental Sciences 2024年第4期37卷 399-405页

作者： hou Yu Shan JIN Yi Chen CAI chang TANG hou Lin QIN Qian Qian LYU Fan National Center for AIDS/STD Control and Prevention Chinese Center for Disease Control and PreventionBeijing 102206China

Objective This study aimed to determine the current epidemiological status of PLWHA aged≥50 years in China from 2018 to 2021.It also aimed to recommend targeted interventions for the prevention and treatment of HIV/AIDS in elderly patients.Methods Data on newly reported cases of PLWHA,aged≥50 years in China from 2018 to 2021,were collected using the CRIMS.Trend tests and spatial analyses were also conducted.Results Between 2018 and 2021,237,724 HIV/AIDS cases were reported among patients aged≥50 years in China.The main transmission route was heterosexual transmission(91.24%).Commercial heterosexual transmission(CHC)was the primary mode of transmission among males,while non-marital non-CHC([NMNCHC];60.59%)was the prevalent route in women.The proportion of patients with CHC decreased over time(Z=67.716,P<0.01),while that of patients with NMNCHC increased(Z=153.05,P<0.01).The sex ratio varied among the different modes of infection,and it peaked at 17.65 for CHC.The spatial analysis indicated spatial clustering,and the high-high clustering areas were mainly distributed in the southwestern and central-southern provinces.Conclusion In China,PLWHA,aged≥50 years,were predominantly infected through heterosexual transmission.The primary modes of infection were CHC and NMNCHC.There were variations in the sex ratio among different age groups,infected through various sexual behaviors.HIV/AIDS cases exhibited spatial clustering.Based on these results,the expansion of HIV testing,treatment,and integrated behavioral interventions in high-risk populations is recommended to enhance disease detection in key regions.

关键词： HIV/AIDS Aged≥50 years China

Photo-thermal synergistic excitation:Feasible strategy to detect ethanol for wide bandgap ZIF-8at low work temperature

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Journal of Environmental Sciences 2024年第4期138卷 112-120页

作者： Shuhao shi Qian Du Ming hou Xiaolei Ye Li Yang Shenghui Guo Jianhong Yi Ullah Ehsan Hongbo Zeng State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Faculty of Metallurgical and Energy EngineeringKunming University of Science and TechnologyKunming 650093China Department of Chemical and Materials Engineering University of AlbertaEdmonton T6G 2V4Canada FEMTO-ST Institute(UMR CNRS 6174) Universite de Bourgogne Franche-Comte(UBFC)Universite de technologie de Belfort Montbéliard(UTBM)Site de MontbeliardBelfort F-90010France Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China

Zeolitic Imidazolate Framework-8(ZIF-8)material was prepared by chemical precipitation method.The microstructure and physical properties of the as-prepared samples were characterized by XRD,BET,FESEM and UV spectrophotometer.The self-made four-channel measurement device was used to test the gas sensitivity of ZIF-8 material toward ethanol gas under photo-thermal synergistic excitation.The results showed that the sample was typical ZIF-8(E_(g)=4.96 eV)with a regular dodecahedron shape and the specific surface is up to 1793 m^(2)/g.The as-prepared ZIF-8 has a gas response value of 55.04 to 100 ppm ethanol at 75℃ and it shows good gas sensing selectivity and repeated stability.The excellent gas sensitivity can be attributed to the increase of free electron concentration in the ZIF-8 conduction band by photo-thermal synergistic excitation,and the large specific surface area of ZIF-8 material provides more active sites for gas-solid surface reaction.The reaction mechanism of ZIF-8 material under multi-field excitation was also discussed.

关键词： ZIF-8 material Photo-thermal synergistic excitation UV-light irradiation Photon-generated electron and hole Gas-sensitive property

Transpiration-prompted Photocatalytic Degradation of Dye Pollutant with AuNPs/PANI Based Cryogels

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Chinese Journal of Polymer Science 2022年第10期40卷 1141-1153,I0006,I0005页

作者： Xiao-Xiao Guo shi-chang hou Jun Chen Cong Liao Wei-Dong He CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

Incautious discharge of organic dyes such as methyl orange(MO)has produced serious pollution to the environment,calling for the efficient techniques to remove them with retaining the green world.The photo-catalytic degradation of organic dyes is promising among the developed techniques.Thus,a strategy based on transpiration-prompted photocatalytic degradation of dye pollutant under sunlight is put forward.Aniline(ANI)is graft-polymerized onto poly(acrylamide-co-N-4-aminophenylacrylamide)(PAAm)cryogel embedded with gold nanoparticles(AuNPs,diameter:4-10 nm).The obtained cryogels integrated with AuNPs and PANI inside PAAm matrix(AuNP@PAAm-g-PANI)have been structurally explored based on the chemical composition and the phase/porous morphology.SEM and TEM observation shows that PANI and AuNPs are uniformly distributed in PAAm matrix.Since the macro-porosity of cryogel,hydrophilicity of PAAm and photo-thermal activity of PANI,PAAm-g-PANI cryogels without AuNPs can have a photo-thermal evaporation rate of water at 1.63 kg·m^(-2)·h^(-1).As a comparison,Au NP@PAAm-g-PANI cryogels with AuNPs exhibit higher one at 2.20 kg·m^(-2)·h^(-1),suggesting the promotion of AuNPs to photo-thermal evaporation.Meanwhile,PANI appreciatively assists AuNPs to display higher catalytic ability for the oxidative degradation of MO.Therefore,the removal of MO from water is obviously prompted by the water transpiration under sunlight with AuNP@PAAm-g-PANI cryogels,whose rate constant can reach to 0.320 h^(-1),being three folds of that for the sole absorption of MO.This transpiration-prompted photocatalytic degradation provides a fascinating route to eliminate organic pollutants and obtain pure water from wastewater simultaneously with sustainable sunlight energy.

关键词： Photothermal evaporation Photocatalytic degradation Sunlight Organic dye Composite cryogel

Atomic-scale mechanism of effect of co-separation of elements at interface of ferrite and austenite on Cr-depleted zone of duplex stainless steel

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Journal of Iron and Steel Research(International) 2024年第3期31卷 710-718页

作者： Yan-hui hou Ze-kun Xu shi-long Zhou Guang-qiang Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Three-dimensional atom-probe tomography and first-principles calculation combined with density functional theory were used to study the effect of the co-segregation of different elements formed during the solidification process of S32205 duplex stainless steel on the Cr-depleted zone at the interface between ferrite and austenite.It was found that the co-segregation of different elements formed during the solidification process of duplex stainless steel can also form Cr-depleted zone at the interface between ferrite and austenite.Moreover,Mo,Si,B,C and P atoms promote co-segregation with Cr atoms,which promotes the formation of Cr-depleted zone at the interface between ferrite and austenite in duplex stainless steel.Mo and Si strongly promote the segregation of Cr at the interface between ferrite and austenite,thereby promoting the formation of Cr-depleted zone.B,C and P elements also promote the segregation of Cr element at the interface between ferrite and austenite and the formation of Cr-depleted zone,but their effect is weaker than that of Mo and Si elements.These conclusions provide a new theoretical basis for improving the intergranular corrosion performance of duplex stainless steel.

关键词： Duplex stainless steel Cr-depleted zone Intergranular corrosion Co-segregation First-principles calculation

Intrinsic pentagon defect engineering in multiple spatial-scale carbon frameworks for efficient triiodide reduction

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Journal of Energy Chemistry 2024年第8期95卷 20-28页

作者： Siyi hou Xuedan Song chang Yu Jiangwei chang Yiwang Ding Yingbin Liu Xiubo Zhang Weizhe Liu Jieshan Qiu State Key Lab of Fine Chemicals Liaoning Key Lab for Energy Materials and Chemical Engineering Frontier Science Center for Smart Materials School of Chemical EngineeringDalian University of Technology Liaoning Key Lab for Energy Materials and Chemical Engineering Frontier Science Center for Smart Materials School of Chemistry Dalian University of Technology State Key Laboratory of Chemical Resource Engineering College of Chemical Engineering Beijing University of Chemical Technology

Intrinsic topological defect engineering has been proven as a promising strategy to elevate the electrocatalytic activity of carbon materials. However, the controllable construction of high-density and specific topological defects in carbon frameworks to reveal the relationship between reactivity and defect structure remains a challenging task. Herein, the intrinsic pentagon carbon sites that can favor electron overflow and enhance their binding affinity towards the intermediates of catalytic reaction are firstly presented by the work function and the p-band center calculations. To experimentally verify this, the cage-opening reaction of fullerene is proposed and utilized for synthesizing carbon quantum dots with specific pentagon configuration(CQDs-P), subsequently utilizing CQDs-P to modulate the micro-scale defect density of three-dimensional reduced graphene oxide(rGO) via π-π interactions. The multiple spatial-scale rGO-conjugated CQDs-P structure simultaneously possesses abundant pentagon and edge defects as catalytic active sites and long-range-ordered π electron delocalization system as conductive network. The defects-rich CQDs-P/rGO-4 all-carbon-based catalyst exhibits superb catalytic activity for triiodide reduction reaction with a high photoelectric conversion efficiency of 8.40%, superior to the Pt reference(7.97%). Theoretical calculations suggest that pentagon defects in the carbon frameworks can promote charge transfer and modulate the adsorption/dissociation behavior of the reaction intermediates, thus enhancing the electrocatalytic activity of the catalyst. This work confirms the role of intrinsic pentagon defects in catalytic reactions and provides a new insight into the synthesis of defects-rich carbon catalysts.

关键词： Carbon quantum dots Defect engineering Electrocatalytic activity Pentagon carbon Triiodide reduction

Synergistic anionic/zwitterionic mixed surfactant system with high emulsification efficiency for enhanced oil recovery in low permeability reservoirs

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Petroleum Science 2024年第2期21卷 936-950页

作者： Hai-Rong Wu Rong Tan shi-Ping Hong Qiong Zhou Bang-Yu Liu Jia-Wei chang Tian-Fang Luan Ning Kang Ji-Rui hou National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing102249China Unconventional Petroleum Research Institute China University of Petroleum-BeijingBeijing102249China Gas Production Plant 5 of PetroChina changqing Oilfield Company PetroChinaXi©an710000ShaanxiChina College of Petroleum Engineering China University of Petroleum-BeijingBeijing102249China College of Science China University of Petroleum-BeijingBeijing102249China Kazakh-British Technical University Almaty050000Kazakhstan

Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.

关键词： Anionic/zwitterionic mixed surfactant system Emulsification Synergistic effect Low permeability reservoir Enhanced oil recovery

Diarrhea induced by insufficient fat absorption in weaned piglets:Causes and nutrition regulation

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Animal Nutrition 2024年第1期16卷 299-305页

作者： Yuying Li Pengjun shi Kang Yao Qian Lin Mansheng Wang Zhenping hou Wenjie Tang Hui Diao Institute of Bast Fiber Crops Chinese Academy of Agricultural Sciences Institute of Subtropical Agriculture Chinese Academy of Sciences Hunan Province Key Laboratory of Animal Nutritional Physiology and Metabolic Process Animal Breeding and Genetics Key Laboratory of Sichuan Province Livestock and Poultry Biological Products Key Laboratory of Sichuan Province Sichuan Animal Science Academy Sichuan Animtech Feed Co. Ltd

Fat is one of the three macronutrients and a significant energy source for piglets. It plays a positive role in maintaining intestinal health and improving production performance. During the weaning period,physiological, stress and diet-related factors influence the absorption of fat in piglets, leading to damage to the intestinal barrier, diarrhea and even death. Signaling pathways, such as fatty acid translocase(CD36), pregnane X receptor(PXR), and AMP-dependent protein kinase(AMPK), are responsible for regulating intestinal fat uptake and maintaining intestinal barrier function. Therefore, this review mainly elaborates on the reasons for diarrhea induced by insufficient fat absorption and related signaling pathways in weaned-piglets, with an emphasis on the intestinal fat absorption disorder. Moreover, we focus on introducing nutritional strategies that can promote intestinal fat absorption in piglets with insufficient fat absorption-related diarrhea, such as lipase, amino acids, and probiotics.

关键词： Weaned piglet Diarrhea Fat absorption Nutrient regulation