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A sample of metal-poor galaxies identified from the LAMOST spectral survey

Research in Astronomy and Astrophysics 2017年第5期17卷 17-30页

作者： Yu-Long Gao Jian-Hui Lian Xu Kong ze-sen lin Ning Hu Hai-Yang Liu En-Ci Wang Zi-Huang Cao Yong-Hui Hou Yue-Fei Wang Yong Zhang CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Scienceand Technology of China Hefei 230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei 230026 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of SciencesBeijing 100012 China Nanjing Institute of Astronomical Optics & Technology National Astronomical Observatories Chinese Academyof Sciences Nanjing 210042 China

We present a sample of 48 metal-poor galaxies at z 〈 0.14 selected from 92 510 galaxies in the LAMOST survey. These galaxies are identified by their detection of the auroral emission line[OⅢ]λ4363 above the 3σ level, which allows a direct measurement of electron temperature and oxygen abundance. The emission line fluxes are corrected for internal dust extinction using the Balmer decrement method. With electron temperature derived from [OⅢ]λλ4959, 5007/[OⅢ]λ4363 and electron density from [SⅡ]λ6731/[SⅡ]λ6717, we obtain the oxygen abundances in our sample which range from 12 ＋ log（O/H） = 7.63（0.09 Z_⊙） to 8.46（0.6 Z_⊙）. We find an extremely metal-poor galaxy with 12 ＋ log（O/H） = 7.63 ± 0.01. With multiband photometric data from FUV to NIR and Hαmeasurements, we also determine the stellar masses and star formation rates, based on the spectral energy distribution fitting and Hα luminosity, respectively. We find that our galaxies have low and intermediate stellar masses with 6.39 ≤ log（M/M_⊙） ≤ 9.27, and high star formation rates（SFRs） with-2.18 ≤ log（SFR/M_⊙yr^（-1）） ≤ 1.95. We also find that the metallicities of our galaxies are consistent with the local T_e-based mass-metallicity relation, while the scatter is about 0.28 dex. Additionally,assuming the coefficient of α = 0.66, we find most of our galaxies follow the local mass-metallicity-SFR relation, but a scatter of about 0.24 dex exists, suggesting the mass-metallicity relation is weakly dependent on SFR for those metal-poor galaxies.

关键词： galaxies: abundances -- galaxies: evolution -- galaxies: starburst -- star formation

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A Spleen Tyrosine Kinase’s Sky in Neuronal Degeneration

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Neuroscience Bulletin 2024年第2期40卷 273-276页

作者： Wan-Yun Zhang sen lin Department of Neurology Xinqiao HospitalThe Second Afliated HospitalArmy Medical UniversityChongqing 400042China Chongqing Institute for Brain and Intelligence Guangyang Bay LaboratoryChongqing 400064China

With the growing elderly population,neurodegenerative disorders like Alzheimer's disease(AD)are emerging as a significant public health *** is widely acknowledged in the scientific community that the accumulation of neurotoxic aggregates,such as amyloid beta(Aβ),within the central nervous system is a major factor in the development of these ***,human genome-wide association studies have identified mutations in microglial receptors that may be linked to a number of neurodegenerative diseases[1].

关键词： Aβ Spleen Alzheimer

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Melt flow,heat transfer and solidification in a flexible thin slab continuous casting mold with vertical-combined electromagnetic braking

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Journal of Iron and Steel Research International 2024年第2期31卷 401-415页

作者： lin Xu ze-feng Han Christian Karcher En-gang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang110819LiaoningChina Key Laboratory of Liaoning Province for Clean Combustion Power Generation and Heating Technology Shenyang Institute of EngineeringShenyang110136LiaoningChina Institute of Thermodynamics and Fluid Mechanics Technische Universität IlmenauIlmenau98684Germany

During continuous casting of steel slabs,the application of electromagnetic braking technology(EMBr)provides an effective tool to influence solidification by controlling the pattern of melt flow in the ***,the quality of the final product can be improved considerably.A new electromagnetic braking(EMBr)method,named vertical-combined electromagnetic braking(VC-EMBr),is proposed to be applied to a flexible thin slab casting(FTSC)*** evaluate the beneficial effects of the VC-EMBr,the melt flow,heat transfer,and solidification processes in the FTSC mold are studied by means of numerical *** detail,a Reynolds-averaged Navier–Stokes turbulence model together with an enthalpy-porosity approach was *** numerical findings are compared with respective simulations using the traditional *** results demonstrate that the application of the VC-EMBr contributes significantly to preventing relative slab *** contrast to the Ruler-EMBr,the additional vertical magnetic poles of the VC-EMBr preferentially suppress the direct impact of jet flow on the narrow face of FSTC mold and considerably diminish the level fluctuation near the meniscus *** instance,by applying a magnetic flux density of 0.3 T,the maximum amplitude of meniscus deflection reduces by about 80%.Moreover,the braking effect of the VC-EMBr effectively improves the homogeneity of temperature distribution in the upper recirculation region and increases the solidified shell thickness along the casting *** this basis,the newly proposed VC-EMBr shows a beneficial effect in preventing relative slab defects for FTSC thin slab continuous casting.

关键词： Electromagnetic braking Mold Melt flow Heat transfer Solidification

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Water and other volatiles on Mars

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National Science Review 2024年第6期11卷 12-14页

作者： sen Hu Yubing Gao Zhan Zhou Liang Gao Yangting lin Key Laboratory of the Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences College of Earth and Planetary Sciences University of Chinese Academy of Sciences

Mars, the intriguing red planet, is one of the planets most similar to the Earth in our solar system. It is widely accepted that Mars could have had a warm and wet climate in its early history supported by numerous lines of evidence, e.g. topography, canyons, outflow channels, presence of phyllosilicates and evaporative salts,sedimentary formation, and many others (e.g.[1]), and thus Mars is believed to once have a potentially habitable environment which could be able to supply fundamental conditions for the evolution of potential lives.

关键词： ISOTOPIC COMPOSITION MARTIAN ATMOSPHERE SUBSURFACE WATER ABUNDANCE TISSINT H2O CO2

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Supporting IrO_(x) nanosheets on hollow TiO_(2) for highly efficient acidic water splitting

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Nano Research 2024年第8期17卷 6903-6909页

作者： Ge Yu Ruilong Li Yanmin Hu Xingen lin ze lin Dongyang Wu Gongming Wang Xun Hong Center of Advanced Nanocatalysis(CAN) Department of Applied ChemistryUniversity of Science and Technology of ChinaHefei 230026China

The efficiency of proton exchange membrane water electrolysis(PEM-WE)for hydrogen production is heavily dependent on the noble metal iridium-based ***,the scarcity of iridium limits the large-scale application of *** address this issue,it is promising to select an appropriate support because it not only enhances the utilization efficiency of noble metals but also improves mass transport under high ***,we supported amorphous IrO_(x) nanosheets onto the hollow TiO_(2) sphere(denoted as IrO_(x)),which demonstrated excellent performance in acidic electrolytic water ***,the annealed IrO_(x)catalyst at 150℃in air exhibited a mass activity of 1347.5 A·gIr^(−1),which is much higher than that of commercial IrO_(2) of 12.33 A·gIr^(−1) at the overpotential of 300 mV for oxygen evolution reaction(OER).Meanwhile,the annealed IrO_(x) exhibited good stability for 600 h operating at 10 mA·cm^(−2).Moreover,when using IrO_(x) and annealed IrO_(x) catalysts for water splitting,a cell voltage as low as 1.485 V can be achieved at 10 mA·cm^(−2).The cell can continuously operate for 200 h with negligible degradation of performance.

关键词： oxygen evolution reaction hydrogen evolution reaction amorphous IrO_(x) hollow TiO_(2) proton exchange membrane water electrolysis

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Complex granular flows of sticky-wet material on flip-flow screens:Calibration of discrete element simulations

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Particuology 2024年第1期84卷 290-308页

作者： Ningning Xu sen Tang Dongdong lin Runhui Geng Xinwen Wang Xihui Liang School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing100083China Department of Mechanical Engineering University of ManitobaWinnipegManitobaR3T 5V6Canada

Discrete element method(DEM)is an effective approach for studying the screening process of flip-flow ***,there have been few studies focusing on the thick layer of sticky-wet particles on flip-flow *** achieve accurate simulations of the thick layer of sticky-wet particles on a flip-flow screen,firstly,the movement law of particle flow was studied,and a multi-regime combination cali-bration method based on characteristics of particle flow regimes was *** on the Plackett-Burman experiment,the curse of dimensionality caused by multi-state and multi-contact parameters was ***,the lifting cylinder,rotating drum,and trampoline tests were carried out to obtain macroscopic reference values under various granular flow *** calibration results were then determined using the response surface method and climbing ***,the calibration results were tested at both macroscopic and mesoscopic scales and compared with a commonly used calibration *** results demonstrate that the calibration method,which considers the multi-state characteristics,improves simulation accuracy by 2%-10%and reduces the simulation error to less than 10%,thus meeting the requirements for engineering optimization of flip-flow screens.

关键词： DEM Complex granular flow Parameter calibration Flip-flow screen Sticky-wet particles Thick layer

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Method of fabricating artificial rock specimens based on extrusion free forming(EFF)3D printing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1455-1466页

作者： Xiaomeng Shi Tingbang Deng sen lin Chunjiang Zou Baoguo Liu Key Laboratory for Urban Underground Engineering of the Ministry of Education Beijing Jiaotong UniversityBeijing100044China School of Civil Engineering Beijing Jiaotong UniversityBeijing100044China Department of Civil Engineering Monash UniversityMelbourne3800Australia

Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock *** 3D printing can create complex fractures,the material still lacks sufficient similarity to natural *** free forming(EFF)is a 3D printing technique that uses clay as the printing material and cures the specimens through high-temperature *** this study,we attempted to use the EFF technology to fabricate artificial rock *** results show the physico-mechanical properties of the specimens are significantly affected by the sintering temperature,while the nozzle diameter and layer thickness also have a certain *** specimens are primarily composed of SiO_(2),with mineral compositions similar to that of natural *** density,uniaxial compressive strength(UCS),elastic modulus,and tensile strength of the printed specimens fall in the range of 1.65–2.54 g/cm3,16.46–50.49 MPa,2.17–13.35 GPa,and 0.82–17.18 MPa,*** is capable of simulating different types of rocks,especially mudstone,sandstone,limestone,and ***,the simulation of hard rocks with UCS exceeding 50 MPa still requires validation.

关键词： Artificial rock 3D printing Extrusion free forming(EFF) Similarity analysis Mechanical properties

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A novel dandelion-based bionic proppant and its transportation mechanism in different types of fractures

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Petroleum Science 2024年第4期21卷 2583-2599页

作者： Jun Li Ming-Yi Wu Xu Han Si-Yuan He ze-Yu lin State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Sichuan Particles Energy and Technology Co. Ltd Chongqing Industry Polytechnic College Petroleum Systems Engineering Faculty of Engineering and Applied Science University of Regina

Low-permeability reservoirs are generally characterized by low porosity and low permeability. Obtaining high production using the traditional method is technologically challenging because it yields a low reservoir recovery factor. In recent years, hydraulic fracturing technology is widely applied for efficiently exploiting and developing low-permeability reservoirs using a low-viscosity fluid as a fracturing ***, the transportation of the proppant is inefficient in the low-viscosity fluid, and the proppant has a low piling-up height in fracture channels. These key challenges restrict the fluid(natural gas or oil) flow in fracture channels and their functional flow areas, reducing the profits of hydrocarbon *** study aimed to explore and develop a novel dandelion-bionic proppant by modifying the surface of the proppant and the fiber. Its structure was similar to that of dandelion seeds, and it had high transport and stacking efficiency in low-viscosity liquids compared with the traditional ***, the transportation efficiency of this newly developed proppant was investigated experimentally using six different types of fracture models(tortuous fracture model, rough fracture model,narrow fracture model, complex fracture model, large-scale single fracture model, and small-scale single fracture model). Experimental results indicated that, compared with the traditional proppant, the transportation efficiency and the packing area of the dandelion-based bionic proppant significantly improved in tap water or low-viscosity fluid. Compared with the traditional proppant, the dandelionbased bionic proppant had 0.1-4 times longer transportation length, 0.3-5 times higher piling-up height, and 2-10 times larger placement area. The newly developed proppant also had some other extraordinary features. The tortuosity of the fracture did not influence the transportation of the novel proppant. This proppant could easily enter the branch fracture and n

关键词： Dandelion-based bionic proppant Low-viscosity fracturing fluid Unconventional reservoir Volumetric fracturing stimulation

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The Effect of Lateral Offset Distance on the Aerodynamics and Fuel Economy of Vehicle Queues

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Fluid Dynamics & Materials Processing 2024年第1期20卷 147-163页

作者： Lili Lei ze Li Haichao Zhou Jing Wang Wei lin School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang212013China

The vehicle industry is always in search of breakthrough energy-saving and emission-reduction *** recent years,vehicle intelligence has progressed considerably,and researchers are currently trying to take advantage of these *** we consider the case of many vehicles forming a queue,i.e.,vehicles traveling at a predetermined speed and distance *** the majority of existing studies on this subject have focused on the influence of the longitudinal vehicle spacing,vehicle speed,and the number of vehicles on aerodynamic drag and fuel economy,this study considers the lateral offset distance of the vehicle *** group fuel consumption savings rate is calculated and *** also demonstrated by experimental results,some aerodynamic benefits ***,the fuel consumption saving rate of the vehicle queue decreases as the lateral offset distance increases.

关键词： Vehicle platoon automotive aerodynamics horizontal offset distance fuel consumption savings rate computational fluid dynamics

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Toward a rapid and convenient nanoplastic quantification method in laboratory-scale study based on fluorescence intensity

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 117-126页

作者： Ruiqi Yan sen lin Qian Ding Lei Zhang Xia Yu Wentao Zhao Qian Sui State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process School of Resources and Environmental EngineeringEast China University of Science and TechnologyShanghai200237China State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai200092China

The thorough investigation of nanoplastics(NPs)in aqueous environments requires efficient and expeditious quantitative analytical methods that are sensitive to environmentally relevant NP concentrations and convenient to *** analysis-based quantitative methods have been acknowledged as effective and rapid approaches for quantifying NP concentrations in laboratory-scale ***,we compared three commonly used optical response indicators,namely fluorescence intensity(FI),ultraviolet absorbance,and turbidity,to assess their performance in quantifying ***,orthogonal experiments were conducted to evaluate the influence of various water quality parameters on the preferred indicator-based quantification *** results revealed that FI exhibits the highest correlation coefficient(>0.99)with NP ***,the limit of quantification(LOQ)for various types of NPs is exceptionally low,ranging from 0.0089 to 0.0584 mg/L in ultrapure water,well below environmentally relevant *** variations in water quality parameters such as pH,salinity,suspended solids(SS),and humic acid,a robust relationship between detectable FI and NP concentration was ***,an increased matrix,especially SS in water samples,results in an enhanced LOQ for ***,the quantitative method remains applicable in real water bodies,especially in drinking water,with NP LOQ as low as 0.0157–0.0711 mg/*** exceeds the previously reported detectable concentration for 100 nm NPs at 40µg/mL using surface-enhanced Raman *** study confirms the potential of FI as a reliable indicator for the rapid quantification of NPs in aqueous environments,offering substantial advantages in terms of both convenience and cost-effectiveness.

关键词： Nanoplastic quantification Fluorescence intensity Drinking water Limit of quantification(LOQ) Matrix effects

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