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Paraffin–CaCl_(2)·6H_(2)O dosage effects on the strength and heat transfer characteristics of cemented tailings backfill

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 60-70页

作者： Hai li Aibing Jin Shuaijun chen Yiqing Zhao You ju Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine University of Science and Technology BeijingBeijing 100083China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China

The challenge of high temperatures in deep mining remains harmful to the health of workers and their production efficiency The addition of phase change materials (PCMs) to filling slurry and the use of the cold storage function of these materials to reduce downhole temperatures is an effective approach to alleviate the aforementioned ***–CaCl_(2)·6H_(2)O composite PCM was prepared in the *** composition,phase change latent heat,thermal conductivity,and cemented tailing backfill (CTB) compressive strength of the new material were *** heat transfer characteristics and endothermic effect of the PCM were simulated using Fluent *** results showed the following:(1) The new paraffin–CaCl_(2)·6H_(2)O composite PCM improved the thermal conductivity of native paraffin while avoiding the water solubility of CaCl_(2)·6H_(2)O.(2) The calculation formula of the thermal conductivity of CaCl_(2)·6H_(2)O combined with paraffin was deduced,and the reasons were explained in principle.(3) The“enthalpy–mass scale model”was applied to calculate the phase change latent heat of nonreactive composite PCMs.(4)The addition of the paraffin–CaCl_(2)·6H_(2)O composite PCM reduced the CTB strength but increased its heat absorption *** research can give a theoretical foundation for the use of heat storage backfill in green mines.

关键词： paraffin–CaCl_(2)·6H_(2)O heat transfer simulation heat calculation phase change material-based backfill latent heat of formula

Intense and Superflat White Laser with 700-nm 3-dB Bandwidth and 1-mJ Pulse Energy Enabling Single-Shot Subpicosecond Pulse Laser Spectroscopy

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Research 2024年第2期6卷 319-327页

作者： lihong Hong Haiyao Yang liqiang liu Mingzhou li Yuanyuan liu Baoqin chen Huakang Yu Wenbo ju Zhi-Yuan li School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China State Key Laboratory of Luminescent Materials and Devices South China University of TechnologyGuangzhou 510640China

An optical spectrometer is a basic spectral instrument that probes microscopic physical and chemical properties of macroscopic objects but generally suffers from difficulty in broadband time-resolved *** this work,we report the creation of ultrabroadband white-light laser with a 3-dB bandwidth covering 385 to 1,080 nm,pulse energy of 1.07 mJ,and pulse duration of several hundred femtoseconds by passing 3-mJ pulse energy,50-fs pulse duration Ti:Sapphire pulse laser through a cascaded fused silica plate and chirped periodically poled lithium niobate *** utilize this unprecedented superflat,ultrabroadband,and intense femtosecond laser light source to build a single-shot(i.e.,single-pulse)subpicosecond pulse laser ultraviolet-visible-near-infrared spectrometer and successfully measure various atomic and molecular absorption *** single-shot ultrafast spectrometer may open up a frontier to monitor simultaneously the ultrafast dynamics of multiple physical and chemical processes in various microscopic systems.

关键词： Pulse utilize frontier

Integrated neural tracing and in-situ barcoded sequencing reveals the logic of SCN efferent circuits in regulating circadian behaviors

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Science China(life Sciences) 2024年第3期67卷 518-528页

作者： Meimei liao Xinwei Gao chen chen Qi li Qingchun Guo He Huang Erquan Zhang Dapeng ju College of Biological Sciences China Agriculture UniversityBeijing 100193China National Institute of Biological Sciences(NIBS) Beijing 102206China Chinese Institute for Brain Research Beijing 102206China School of Biomedical Engineering Capital Medical UniversityBeijing 100069China Department of Anesthesiology The Second Affiliated HospitalChongqing Medical UniversityChongqing 401336China Tsinghua Institute of Multidisciplinary Biomedical Research Tsinghua UniversityBeijing 102206China

The circadian clock coordinates rhythms in numerous physiological processes to maintain organismal homeostasis. Since the suprachiasmatic nucleus(SCN) is widely accepted as the circadian pacemaker, it is critical to understand the neural mechanisms by which rhythmic information is transferred from the SCN to peripheral clocks. Here, we present the first comprehensive map of SCN efferent connections and suggest a molecular logic underlying these projections. The SCN projects broadly to most major regions of the brain, rather than solely to the hypothalamus and thalamus. The efferent projections from different subtypes of SCN neurons vary in distance and intensity, and blocking synaptic transmission of these circuits affects circadian rhythms in locomotion and feeding to different extents. We also developed a barcoding system to integrate retrograde tracing with in-situ sequencing, allowing us to link circuit anatomy and spatial patterns of gene expression. Analyses using this system revealed that brain regions functioning downstream of the SCN receive input from multiple neuropeptidergic cell types within the SCN, and that individual SCN neurons generally project to a single downstream brain *** map of SCN efferent connections provides a critical foundation for future investigations into the neural circuits underlying SCNmediated rhythms in physiology. Further, our new barcoded tracing method provides a tool for revealing the molecular logic of neuronal circuits within heterogeneous brain regions.

关键词： circadian rhythms SCN output circuit neural tracing barcoded GFP in situ sequencing

On convergence of covariance matrix of empirical Bayes hyper-parameter estimator

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Control Theory and Technology 2024年第2期22卷 149-162页

作者： Yue ju Biqiang Mu Tianshi chen School of Data Science and Shenzhen Research Institute of Big Data The Chinese University of Hong KongShenzhenShenzhen518172GuangdongChina Division of Decision and Control Systems School of Electrical Engineering and Computer ScienceKTH Royal Institute of Technology10044StockholmSweden Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and System ScienceChinese Academy of SciencesBeijing100190China

Regularized system identification has become the research frontier of system identification in the past *** related core subject is to study the convergence properties of various hyper-parameter estimators as the sample size goes to *** this paper,we consider one commonly used hyper-parameter estimator,the empirical Bayes(EB).Its convergence in distribution has been studied,and the explicit expression of the covariance matrix of its limiting distribution has been ***,what we are truly interested in are factors contained in the covariance matrix of the EB hyper-parameter estimator,and then,the convergence of its covariance matrix to that of its limiting distribution is *** general,the convergence in distribution of a sequence of random variables does not necessarily guarantee the convergence of its covariance ***,the derivation of such convergence is a necessary complement to our theoretical analysis about factors that influence the convergence properties of the EB hyper-parameter *** this paper,we consider the regularized finite impulse response(FIR)model estimation with deterministic inputs,and show that the covariance matrix of the EB hyper-parameter estimator converges to that of its limiting ***,we run numerical simulations to demonstrate the efficacy of ourtheoretical results.

关键词： Regularized system identification Hyper-parameter estimator Empirical Bayes Convergence of covariance matrix

Durable Ru Nanocrystal with HfO_(2)Modification for Acidic Overall Water Splitting

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Nano-Micro Letters 2024年第9期16卷 462-477页

作者： Xiangkai Kong Jie Xu Zhicheng ju Changle chen School of Materials and Physics China University of Mining and TechnologyXuzhou 221116JiangsuPeople’s Republic of China Anhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation Huaibei Normal UniversityHuaibei 235000AnhuiPeople’s Republic of China School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026AnhuiPeople’s Republic of China School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210023JiangsuPeople’s Republic of China

Durable and efficient bi-functional catalyst,that is capable of both oxygen evolution reaction and hydrogen evolution reaction under acidic condition,are highly desired for the commercialization of proton exchange membrane water ***,we report a robust L-Ru/HfO_(2)heterostructure constructed via confining crystalline Ru nanodomains by HfO_(2)*** assembled with a proton exchange membrane,the bi-functional L-Ru/HfO_(2)catalyst-based electrolyzer presents a voltage of 1.57 and 1.67 V to reach 100 and 300 mA cm^(-2)current density,prevailing most of previously reported Ru-based materials as well as commercial Pt/C||RuO_(2)*** is revealed that the synergistic effect of HfO_(2)modification and small crystalline domain formation significantly alleviates the over-oxidation of *** importantly,this synergistic effect facilitates a dual-site oxide path during the oxygen evolution procedure via optimization of the binding configurations of oxygenated *** a result,the Ru active sites maintain the metallic state along with reduced energy barrier for the rate-determining step(^(*)O→^(*)OOH).Both of water adsorption and dissociation(Volmer step)are strengthened,while a moderate hydrogen binding is achieved to accelerate the hydrogen desorption procedure(Tafel step).Consequently,the activity and stability of acidic overall water splitting are simultaneously enhanced.

关键词： Ruthenium Hafnium dioxide Oxygen evolution catalysis Anti-oxidation

Photosynthetic response dynamics in the invasive species Tithonia diversifolia and two co-occurring native shrub species under fluctuating light conditions

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Plant Diversity 2024年第2期46卷 265-273页

作者： ju li Shu-Bin Zhang Yang-Ping li CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunMengla 666303YunnanChina University of Chinese Academy of Sciences Beijing 100049China

To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native ***,few studies have compared the photosynthetic dynamics between invasive and native species during light *** compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady *** photosynthetic dynamics and leaf traits differed among *** showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun ***,the slow induction response may be attributed to the longer stomatal length in *** had a significant effect on photosynthetic dynamics in *** and *** but not in *** shady habitat,*** had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in *** than in the two native *** contrast,*** had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic ***,in both habitats,*** had an overall higher carbon gain during light fluctuations than the two native *** results indicated that *** can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.

关键词： Invasive plant Photosynthetic induction Photosynthetic relaxation Carbon gain Stomatal traits Tithonia diversifolia

Impact of the Complex Terrain in Beijing on Formation of Low-Level Jets

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Journal of Meteorological Research 2024年第1期38卷 138-150页

作者： li’ao ZHOU chenggang WANG Shiguang MIAO ju li School of Atmospheric Physics Nanjing University of Information Science&TechnologyNanjing 210044 Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089 Key Laboratory of Urban Meteorology China Meteorological AdministrationBeijing 100089

This study investigated how the Taihang Mountains and the Yanshan Mountains affect low-level jets(LLJs)in the Beijing area,based on conventional radiosonde observations from Nanjiao Observatory(2016–2017)and high-resolution Weather Research and Forecasting–Advanced Research WRF(WRF-ARW)model *** of radiosonde observations indicated that LLJs in the study area are mainly from the southwest and northwest directions,with occurrence frequency of 44.6%and 33.0%,***(northwest)LLJs are aligned parallel(perpendicular)to the orientation of the Taihang Mountain *** sensitivity experiments using the WRF-ARW model were then conducted to examine the effects of terrain forcing on the northwest and southwest LLJs,with adopted terrain heights of 100%and 50%.The results showed that for northwest LLJs,reduction in the elevation of the Taihang Mountain Range led to weakening of jet intensity by approximately 20%and reduction in jet maximum height by approximately 250 m;lowering the Yanshan Mountain Range had minor influence on the northwest LLJs,with only a 5.2%reduction in intensity and no substantial change in jet maximum *** southwest LLJs,reduction in the elevation of both the Taihang and Yanshan Mountain ranges resulted in minor changes in the intensity and height of the *** analysis revealed that the topography in the Beijing area could modulate the height and intensity of the stable layer by altering the inversion structure within the boundary *** LLJs can develop rapidly within the stable layer,and both the location and the scale of the jet core exhibited reasonable agreement with the extent of the stable layer.

关键词： low-level jets(LLJs) mesoscale numerical simulation terrain forcing

Multi-scale analyses of phase transformation mechanisms and hardness in linear friction welded Ti17(a+β)/Ti17(β)dissimilar titanium alloy joint

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Chinese Journal of Aeronautics 2024年第1期37卷 312-324页

作者： Zhenguo GUO Tiejun MA Xiawei YANG ju li Wenya li Achilles VAIRIS State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical UniversityXi’an 710072China Aeronautical Key Laboratory for Welding and Joining Technologies AVIC Manufacturing Technology InstituteBeijing 100024China Mechanical Engineering Department University of West AtticaAthens 12241Greece

The Ti17(a+β)-Ti17(β)dual alloy-dual property blisk produced using linear Friction Welding(LFW)is considered as high-performance component in advanced ***,up to now,microstructure evolution and relationship between microstructure and micro mechanical properties of LFWed Ti17(a+β)/Ti17(β)dissimilar joint have not been thoroughly *** this work,complex analyses of the phase transformation mechanisms of the joint are conducted,and phase transformations in individual zones are correlated to their microhardness and *** reveal that a dissolution occurs under high temperatures encountered during LFW,which reduces microhardness of the joint to that of Ti17(a+β)and Ti17(β).In ThermoMechanically Affected Zone of Ti17(a+β)(TMAZ-(a+β))side joint,a large number of nanocrystalline a phases form with different *** microstructure strengthens significantly by fine grains which balances partial softening effect of a dissolution,and increases nanohardness of a phase and microhardness of TMAZ-(a+β).Superlattice metastableβphase precipitates from metastableβin Weld Zone(WZ)during quick cooling following welding,because of short-range diffusion migration of solute atoms,especiallyβstabilizing elements Mo and *** precipitation of the superlattice metastableβphase results in precipitation strengthening,which in turn increases nanohardness of metastableβand microhardness in WZ.

关键词： linear friction welding Ti17 titanium alloy Phase transformation Microhardness Nanohardness

Paleoclimatic application of spectral parameters to the eolian red clay of the Jianzha Basin,northeastern margin of the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1952-1966页

作者： Chaofeng FU ju’e TIAN Xinwen XU Yougui SONG jun ZUO Feng WANG lin chen Pengfei li Xiaoke QIANG The School of Earth Science and Resources Chang’an UniversityXi’an 710054China State Key Laboratory of Loess and Quaternary Geology Institute of Earth and EnvironmentCASXi’an 710061China College of Urban and Environmental Science Northwest UniversityXi’an 710069China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China

Reflectance spectroscopy is rapid,inexpensive,and non-destructive and can provide important information about the mineralogy of rocks and *** measured the reflectance spectroscopy of Miocene red clay deposits on the northeastern margin of the Tibetan Plateau,with the aim of developing a rapid methodology for detecting paleoclimatic *** obtained visible/near-infrared(VNIR)and short-wave infrared(SWIR)spectroscopy data from the red clay in the Jianzha Basin,and analyzed their relationship with independent paleoclimatic records,including mineral contents and environmental magnetic *** results show that the VNIR parameters,including D500,D900,R500,and R900(where D and R represent the depth and reflectance of the absorption peaks around 500 and 900 nm,respectively)are temperature-sensitive and correlated with the magnetic susceptibility,frequency-dependent magnetic susceptibility,and the marine δ^(18)O *** results of frequency-domain analysis of the VNIR parameters show that they reflect climate change on orbital *** parameters,such as AS1400,D1400/D1900 and D1900(where AS represents the asymmetry of the absorption peaks around1400 nm),are correlated with the illite and montmorillonite content,and they are sensitive to the weathering *** spectral parameters of the eolian red clay in the Jianzha Basin reflect regional climatic changes caused by the uplift of the Tibetan Plateau at~8.5 Ma and global climatic cooling at~7.2 Ma,and thus they are applicable as both regional and global paleoenvironmental indicators.

关键词： Visible/near-infrared spectroscopy Short-wave infrared spectroscopy Paleoclimatic indicators Red clay Tibetan Plateau

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