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Experimental investigation for temperature and emissivity by flame emission spectrum in a cavity of rocket based combined cycle combustor chamber

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Defence Technology（防务技术） 2024年第9期39卷 114-122页

作者： Weiguang Cai Shu Zheng Yan Wang Bing Liu Shaohua Zhu Li zhao qiang Lu National Engineering Research Center of New Energy Power Generation North China Electric Power UniversityBeijing 102206China Science and Technology on Combustion Internal Flow and Thermal-structure LaboratoryNorthwestern Polytechnical UniversityXi'an 710072China

Flame temperature and spectral emissivity were the important parameters characterizing the sufficient degree of fuel combustion and the particle radiative characteristics in the Rocket Based Combined Cycle(RBCC)*** investigate the combustion characteristics of the complex supersonic flame in the RBCC combustor,a new radiation thermometry combined with Levenberg-Marquardt(LM)algorithm and the least squares method was proposed to measure the temperature,emissivity and spectral radiative properties based on the flame emission ***-situ measurements of the flame temperature,emissivity and spectral radiative properties were carried out in the RBCC direct-connected test bench with laser-induced plasma combustion enhancement(LIPCE)and without *** flame average temperatures at fuel global equivalence ratio(a)of 1.0b and 0.6 with LIPCE were 4.51%and 2.08%higher than those without *** flame combustion oscillation of kerosene tended to be stable in the recirculation zone of cavity with the thermal and chemical effects of laser induced *** differences of flame temperature at a=1.0b and 0.6 were 503 K and 523 K with LIPCE,which were 20.07%and42.64%lower than those without *** flame emissivity with methane assisted ignition was 80.46%lower than that without methane assisted ignition,due to the carbon-hydrogen ratio of kerosene was higher than that of *** spectral emissivities at 600 nm with LIPCE were 1.25%,22.2%,and 4.22%lower than those without LIPCE at a=1.0a(with methane assisted ignition),1.0b(without methane assisted ignition)and *** effect of concentration in the emissivity was removed by normalization to analyze the flame radiative properties in the RBCC combustor *** maximum differences of flame normalized emissivity were 50.91%without LIPCE and 27.53%with *** flame radiative properties were stabilized under the thermal and chemical effects of laser induced plasma at a=0.6.

关键词： Rocket-based combined-cycle Supersonic combustion Flame temperature measurement Emissivity Laser induced plasma combustion enhancement

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Hourly land surface temperature retrieval over the Tibetan Plateau using Geo-LightGBM framework: Fusion of Himawari-8 satellite, ERA5 and site observations

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Advances in Climate Change Research 2024年第4期15卷 623-635页

作者： zhao-Hua LIU Shan-Shan WENG zhao-Liang zeNG Ming-Hu DING Ya-qiang WANG Zhehao LIANG Civil and Surveying&Mapping Engineering Jiangxi University of Science and TechnologyGanzhou 341000China State Key Laboratory of Severe Weather Chinese Academy of Meteoroogical Sciences Beijing 100081China Space Geodesy and Geoinformation Technical Unviersity of BerlinBerlin 10623Germany

The Tibetan Plateau(TP)is highly sensitive to even minor fluctuations in land surface temperature(LST),which can result in permafrost melting and degradation of alpine grasslands,leading to serious ecological ***,it is crucial to have high-temporal-resolution and seamless hourly estimating and monitoring of LST for a better understanding of climate change on the ***,we employed Himawari-8 satellite,Digital Elevation Model(DEM),ERA5 reanalysis and meteorological station observations data to develop a new LightGBM framework(called Geo-LightGBM)for estimating LST on the TP,and then analyzed the spatiotemporal variations of those ***-LightGBM demonstrated excellent LST estimation accuracy,with an R2(coefficient of determination)of 0.971,RMSE(root-mean-square error)of 2.479℃,and MAE(mean absolute error)of 1.510℃.The estimated LST values for the year 2020 agreed well with observed values,with remarkable differences in hourly LST ***,the estimated LST was more accurate than that from ***,there were two high LST centers,located in the Yarlung Zangbo River Basin and the Qaidam Basin,and a low LST center located in the central *** SHAP(SHapley Additive exPlanations)and correlation analyses revealed DSCS(the mean ground downward shortwave radiation under clear-sky conditions)to be the most importantly input variable for estimating *** dummy variables(e.g.,longitude,latitude,DEM)were also found to be crucial for model accuracy *** findings indicate the potential for constructing a high-precision and seamless 24-h LST real-time retrieval and monitoring platform for the TP by combining satellite and China's independently developed CLDAS(China Land Data Assimilation System)data in future.

关键词： Tibetan Plateau Himawari-8 ERA5 Land surface temperature Geo-LightGBM

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Marginal land in China suitable for bioenergy crops under diverse socioeconomic and climate scenarios from 2020 to 2100

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Big Earth Data 2024年第3期8卷 566-586页

作者： Jingying Fu qiang Gao Gang Lin Dong Jiang Yanan zhao Shuang Lue Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijingChina College of Resources and Environment University of Chinese Academy of SciencesBeijingChina Key Laboratory of Coupling Processes and Effects of Natural Resource Elements Ministry of Natural ResourcesBeijingChina Key Laboratory of Carrying Capacity Assessment for Resource and Environment Ministry of Natural ResourcesBeijingChina College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)BeijingChina

Maximizing the development of renewable energy plays a critical role in mitigating the climate *** land provides space for the development of biomass energy;however,it remains unclear how the amount and spatial distribution of marginal land that is suitable for energy crop development will change in the ***,we project energy marginal land changes in China following the shared socioeconomic pathway(SSP)and/or repre-sentative concentration path(RCP).We provide datasets of mar-ginal land,agriculturally suitable land,and potentially suitable for energy crops under historical scenarios and six future scenarios(***1-1.9,SSP1-2.6,SSP4-3.4,SSP2-4.5,SSP4-6.0,and SSP3-7.0)for the period 2020-2100,with a spatial resolution of 5 *** the six scenarios,from 2020-2100,the area of suitable marginal land ranged from 1.90-16.28(Jatropha curcas L.)to 37.37-73.97(Panicum virgatum L.)(×10^(4)km^(2)),depending on the choice of energy crops and climate *** on the growing suitability of eight important bioenergy crops-Ricinus communis L.,Saccharum officinarum L.,Pistacia chinensis Bunge,Panicum virga-tum L.,Jatropha curcas L.,Miscanthus giganteus J.,Manihot esculenta Crantz,and Sorghum bicolor Moench-our dataset can be used to identify suitable locations for specific energy *** new syn-thetic dataset could support the development of multiscenariobased solutions related to carbon neutrality,ecosystem services,and energy transition.

关键词： Marginal land climate change energy crops liquid fuel

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Online Learning Behavior Analysis and Prediction Based on Spiking Neural Networks

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Journal of Social Computing 2024年第2期5卷 180-193页

作者： Yanjing Li Xiaowei Wang Fukun Chen Bingxu zhao qiang Fu the Institute of Education Science Research Heilongjiang UniversityHarbin 150080China the School of Cyberspace Security Shandong University of Political Science and LawJinan 250014China the School of Computer Science and Technology Harbin Engineering UniversityHarbin 150001China the Faculty of Electrical and Computer Engineering University of VictoriaVictoriaV8P 5C2Canada. the Guangxi Key Lab of Brain-Inspired Computing and Intelligent Chips School of Electronic and Information EngineeringGuangxi Normal UniversityGuilin 541004China

The vast amount of data generated by large-scale open online course platforms provide a solid foundation for the analysis of learning behavior in the field of *** study utilizes the historical and final learning behavior data of over 300000 learners from 17 courses offered on the edX platform by Harvard University and the Massachusetts Institute of Technology during the 2012-2013 academic *** have developed a spike neural network to predict learning outcomes,and analyzed the correlation between learning behavior and outcomes,aiming to identify key learning behaviors that significantly impact these *** goal is to monitor learning progress,provide targeted references for evaluating and improving learning effectiveness,and implement intervention measures *** results demonstrate that the prediction model based on online learning behavior using spiking neural network achieves an impressive accuracy of 99.80%.The learning behaviors that predominantly affect learning effectiveness are found to be students’academic performance and level of participation.

关键词： online learning learning outcomes prediction learning behavior analysis spiking neural network

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A magic organic molecule assembled capping layer enables airprocessed α-FAPbI_(3) perovskite solar cell with state-of-the-art performances

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Journal of Semiconductors 2024年第10期45卷 3-6页

作者： Yulong Wang Xiuwen Xu Shujuan Liu qiang zhao College of Electronic and Optical Engineering and College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China State Key Laboratory of Organic Electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced MaterialsNanjing University of Posts and TelecommunicationsNanjing 210023China

The black-phase formamidine-lead iodide(α-FAPbI_(3)),boasting an optimal bandgap of 1.5 eV,stands out as a premier choice for narrow-bandgap perovskite solar cells(PSCs),achieving a certified power conversion efficiency(PCE)of 26.1%[1−5].This impressive performance hinges on the orderly and homogeneous crystallization ofα-phase pure FAPbI_(3),facilitated by coordinating solvents such as dimethyl sulfoxide(DMSO)to form intermediates like PbI_(2)-DMSO complex(D-complex).The D-complex plays a pivotal role in crystallization thermodynamics,enabling the direct formation of α-FAPbI_(3) without the photoinactiveδ-phase[6−9].However,DMSO,a commonly used coordinating solvent,is highly hygroscopic and prone to hydration upon moisture *** tendency leads to incomplete perovskite crystallization and accelerates the transformation of α-FAPbI_(3) into itsδ-phase[2,10].Consequently,the best-performing α-FAPbI_(3)PSCs must be processed in an inert atmosphere with strictly controlled relative humidity(RH)and suffers from relatively poor *** the hard-to-control atmosphere at industrial scale,it is challenging yet imperative to eliminate the negative effects stemming from hygroscopic coordinating solvents[11−13].

关键词： perovskite crystallization enable

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Effects of water molecules on luminescence in europium and terbium coordination polymers with p-fluorobenzoic acid as ligand

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Journal of Rare Earths 2024年第7期42卷 1258-1264,I0003页

作者： Xiaoqi zhao Puyan Hao Yami Ling Mengzhen Jia Rui Zhu Jiawen Liu qiang Xu Jianhong Zhou Collaborative Innovation Center of Rare-Earth Optical Functional Materials and Devices Development Baoji Key Laboratory of Micro-Nano Optoelectronics and Terahertz TechnologySchool of Physics and Opto-Electronic TechnologyBaoji University of Arts and SciencesBaoji721016China

Our previous experimental observations show that the crystal structure of lanthanide luminescent complexes synthesized in aqueous solution usually contains a large number of coordination water molecules or free water *** order to probe the influence of water molecules on luminescent processes of lanthanide complexes,the photoluminescence properties of Ln-FBA(Ln=Eu and Tb,FBA=p-fluorobenzoic acid)coordination polymers at different ambient temperatures,in different solvents and aqueous DMSO solutions with different volume concentrations were systematically *** experiment results show that the presence of water molecules can promote the energy transfer from FBA ligand to Ln3+,at the same time,can cause luminescent non-radiation quenching of lanthanide *** addition,the variation of emission intensity ratio of 615 nm/591 nm peaks of Eu^(3+)with increasing the volume concentration of H_(2)O can be potentially used for the quantitatively detection of water traces in organic *** order to suppress the non-radiation quenching caused by the water molecules,Ln-FBA(Ln=Eu and Tb)coordination polymers were embedded into the PVP matrix to prepare Ln-FBA@PVP hybrid *** photoluminescence investigation indicates that PVP can not only block the quenching effect of water molecules on luminescence,but also effectively sensitize Eu^(3+)and Tb^(3+)*** experimental conclusions are useful for probing the influence of water molecules on luminescent processes of lanthanide complexes,quantitatively detecting water traces in organic solvents and enhancing the photoluminescence intensity in lanthanide complexes.

关键词： Lanthanide complexes Photoluminescence Luminescent quenching Rare earths

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Theoretical analysis of the elastic Kelvin-Helmholtz instability in explosive weldings

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Defence Technology（防务技术） 2024年第2期32卷 521-528页

作者： Yuanbo Sun Jianning Gou Cheng Wang qiang Zhou Rui Liu Pengwan Chen Tonghui Yang Xiang zhao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Beijing HIWING Scientific and Technological Information Institute Beijing100084China School of Aerospace Engineering Tsinghua UniversityBeijing100084China

By considering the joint effects of the Kelvin-Helmholtz(KH) and Rayleigh-Taylor(RT) instabilities, this paper presents an interpretation of the wavy patterns that occur in explosive welding. It is assumed that the elasticity of the material at the interface effectively determines the wavelength, because explosive welding is basically a solid-state welding process. To this end, an analytical model of elastic hydrodynamic instabilities is proposed, and the most unstable mode is selected in the solid phase. Similar approaches have been widely used to study the interfacial behavior of solid metals in high-energy-density physics. By comparing the experimental and theoretical results, it is concluded that thermal softening,which significantly reduces the shear modulus, is necessary and sufficient for successful welding. The thermal softening is verified by theoretical analysis of the increase in temperature due to the impacting and sliding of the flyer and base plates, and some experimental observations are qualitatively *** summary, the combined effect of the KH and RT instabilities in solids determines the wavy morphology, and our theoretical results are in good qualitative agreement with experimental and numerical observations.

关键词： Explosive welding Hydrodynamic instabilities Elasticity

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Reversibly sensitizing-storing-releasing ^(1)O_(2) within a single platinum(Ⅱ)-acetylide-based metallacycle molecule via laser power modulation

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Science China Chemistry 2024年第2期67卷 604-611页

作者： Ruyi Zhou Wen Lv Bo Li Bo Yu Sudi Zhang Yucheng Zhou Shujuan Liu qiang zhao State Key Laboratory of Organic Electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)&Institute of Flexible Electronics(Future Technology)Nanjing University of Posts and Telecommunications(NUPT)Nanjing210023China College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Jiangsu Province Engineering Research Center for Fabrication and Application of Special Optical Fiber Materials and DevicesNanjing University of Posts and Telecommunications(NUPT)Nanjing210023China

Tumor hypoxia severely limits the therapeutic efficacy of photodynamic therapy(PDT) for solid tumors,which is highly dependent on tissue oxygen *** this study,we developed a platinum(Ⅱ)-acetylide-based metallacycle compound bearing six 1,4-dimethylnaphthalenes(DMN) groups,and controlled the photodynamic and photothermal effects of the compound by adjusting the power of 730 nm laser to achieve reversible sensitization,storage and release of 1~O_(2) within a single *** compound formed nanoparticles by self-assembly and exhibited good water solubility and *** laser irradiation,the strong spin-orbit coupling of platinum atoms in the metallacycle facilitated 1~O_(2) *** produced 1~O_(2) was captured by the DMN carriers and transported into the hypoxic tumor,where 1~O_(2) release was triggered owing to the good photothermal effect of the extended conjugation of the *** therapy,the metallacycle serving as a photosensitizer,1~O_(2) carrier,and photothermal reagent,achieved the synergistic therapy of PDT/PTT,demonstrating the versatility of the *** study proposes a new strategy to develop phototherapy agents that are suitable for hypoxic tumors.

关键词： metallacycles singlet oxygen endoperoxides near-infrared absorption synergistic treatment

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Influence of filler characteristics on particle removal in fluid catalytic cracking slurry under an alternating electric field

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Petroleum Science 2024年第3期21卷 2102-2111页

作者： qiang Li Hui-Zhen Yang Can Yang Qing-Zhu Qiu Wei-Wei Xu zhao-zeng Liu College of New Energy China University of Petroleum(East China)Qingdao266580ShandongChina

The characteristics of the packing material under an alternating electric field are an important factor in the removal of FCCS *** this study,the electric field distribution of a separation unit consisting of packed spheres under an alternating electric field is simulated,and the movement mechanism of catalyst particles is ***"effective contact point"model is derived to predict the adsorption of filler contact points on catalyst particles under the alternating electric field,and the model is validated by simulations and *** numerical calculation and experimental results indicate that the electrical properties of the filler spheres,the filler angleθ,and the frequency f of the alternating electric field affect the adsorption of catalyst *** the frequency of the electric field increases,the particle removal efficiency of the high-conductivity filler(silicon carbide)increases and then settles,and the separation efficiency of the low-conductivity filler(glass,zirconia)is not sensitive to the change in electric field frequency.

关键词： Fluid catalyticcracking slurry(FCCS) Particle AC electric field Fillers Removal

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Advances in ice avalanches on the Tibetan Plateau

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Journal of Mountain Science 2024年第6期21卷 1814-1829页

作者： TANG Minggao LI Guang zhao Huanle XU qiang WU Guangjian YANG Wei GUO Daojing State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Environment and Civil Engineering Chengdu University of TechnologyChengdu 610059China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China

As some of the greatest natural disasters in the cryosphere,ice avalanches(IAs)seriously threaten lives and cause catastrophic damage to the resource environment,but a comprehensive overview of the state of knowledge on IAs remains *** summarized 63 IAs on the Tibetan Plateau(TP)since the 20th century,of which,over 20 IAs occurred after the 21st *** distributions of IAs are mainly concentrated in the southeastern and northwestern TP,and the occurrence time of IAs is mostly concentrated from July to *** highlight recent advances in mechanical properties and genetic mechanisms of IAs and emphasize that temperature,rainfall,and seismicity are the inducing *** failure modes of IAs are summarized into 6 categories by examples:slip pulling type,slip toppling type,slip breaking type,water level collapse type,cave roof collapse type,and wedge failure ***,we deliver recommendations concerning the risk assessment and prediction of *** results provide important scientific value for addressing climate change and resisting glacier-related hazards.

关键词： Ice avalanche Global warming Genetic mechanism Risk assessment Tibetan Plateau

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