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Effect of Lanthanum on Catalytic Growth of Carbon Nanotubes from Methane over Nickel-Aluminum Catalyst

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Journal of Rare Earths 2004年第z1期22卷 172-174页

作者： ju yan li fengyi Wei Renzhong Rao Richuan Department of Chemistry Nanchang University Nanchang 330047 China Department of Chemistry Nanchang University Nanchang 330047 China Department of Chemistry Nanchang University Nanchang 330047 China Department of Chemistry Nanchang University Nanchang 330047 China

The synthesis of carbon nanotubes (CNTs) from methane decomposition by Ni-La-Al (Ni/La/Al = 10: 1:9) and Ni-Al (Ni/A1 = 1:1 ) catalysts at 1023 K was *** were prepared by a co-precipitation *** the methane decomposition, a part of gases at the exit of the reactor was analyzed by gas *** experimental results show that doping La into Ni-A1 catalyst improves the catalytic lifetime and the yields of CNTs in the methane *** characteristics of CNTs were investigated by TEM and *** analyses show that CNTs deposited on the Ni-La-A1 catalyst have obvious thinner walls, less bend structures and better graphitization than the sample grown over *** results indicate that the introduction of lanthanum into the nickel-aluminum catalyst leads to significant changes in the morphology and microstructures of the CNTs.

关键词： rare earth doping catalyst carbon nanotubes

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

Isotopic dependence of the yield ratios of light fragments from different projectiles and their unified neutron skin thicknesses

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Nuclear Science and Techniques 2024年第3期35卷 228-236页

作者： Ting-Zhi yan Shan li School of Energy and Power Engineering Northeast Electric Power UniversityJilin 132012China

The yield ratios of neutron-proton(R(n/p))and^(3)H-^(3)He(R(^(3)H∕^(3)He))with reduced rapidity from 0 to 0.5 were simulated at 50 MeV/u even-even ^(36−56)Ca+^(40)Ca,even-even ^(48−78)Ni+^(58)Ni,and ^(100−139)Sn(every third isotopes)+112 Sn for full reduced impact parameters using the isospin-dependent quantum molecular dynamics(IQMD)*** neutron and proton density distributions and root-mean-square radii of the reaction systems were obtained using the Skyrme-Hartree-Fock model,which was used for the phase space initialization of the projectile and target in *** defined the unified neutron skin thickness asΔRnp=^(1∕2) n−^(1∕2)p,which was negative for neutron-deficient *** unifiedΔRnp values for nuclei with the same relative neutron excess from different isotopic chains were nearly equal,except for extreme neutron-rich isotopes,which is a type of scaling *** yield ratios of the three isotopic chain-induced reactions,which depended on the reduced impact parameter and unified neutron skin thickness,were *** results showed that both R(n/p)and R(^(3)H∕^(3)He)decreased with a reduced impact parameter for extreme neutron-deficient isotopes;however,they increased with reduced impact parameters for extreme neutron-rich isotopes,and increased with theΔRnp of the projectiles for all reduced impact *** addition,a scaling phenomenon was observed betweenΔR np and the yield ratios in peripheral colli-sions from different isotopic chain projectiles(except for extreme neutron-rich isotopes).Thus,R(n/p)and R(^(3)H∕^(3)He)from peripheral collisions were suggested as experimental probes for extracting the neutron or proton skin thicknesses of non-extreme neutron-rich nuclei from different isotopic chains.

关键词： Exotic nuclei Unified neutron skin thickness Yield ratios IQMD

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

Large eddy simulation study of 3D wind field in a complex mountainous area under different boundary conditions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 541-556页

作者： yan li Lei yan Xuhui HE School of Civil Engineering Central South UniversityChangsha410075China National Engineering Research Center for High-speed Railway Construction Changsha410075China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structures Changsha410075China

Large eddy simulations generally are used to predict 3D wind field characteristics in complex mountainous *** simulation boundary conditions,such as the height and length of the computational domain or the characteristics of inflow turbulence,can significantly impact the quality of *** this study,we examined these boundary conditions within the context of the mountainous terrain around a long-span cable-stayed bridge using a wind tunnel *** sizes of computational domains and turbulent incoming wind velocities were used in large eddy *** results show that when the height of the computational domain is five times greater than the height of the terrain model,there is minimal influence from the top wall on the wind field characteristics in this complex mountainous *** the length of the wake region of the computational domain has negligible effects on the wind *** in the inlet boundary reduces the length of the wake region on a leeward hill with a low slope,but has less impact on the mean wind velocity of steep hills.

关键词： Large eddy simulation(LES) Spectral representation method Recycling method High mountainous canyon Wind characteristics Atmospheric boundary layer Computational domain

Transcription factor Foxp1 is essential for the induction of choroidal neovascularization

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Eye and Vision 2024年第3期10卷 1-12页

作者： Meifang yan junjian li li yan Xue li Jie-Guang Chen School of Ophthalmology and Optometry and Eye Hospital Wenzhou Medical UniversityState Key Laboratory of OptometryOphthalmology and Vision Scienceand Zhejiang Provincial Key Laboratory of Optometry and Ophthalmology270 Xueyuan RoadWenzhouZhejiang325027People’s Republic of China Joint Shantou International Eye Center(JSIEC)of Shantou University and the Chinese University of Hong Kong ShantouGuangdong515000People’s Republic of China

Background The exudative form of age-related macular degeneration(AMD)is characterized by abnormal blood vessel growth,which is stimulated by vascular endothelial growth factor(VEGF)released from retinal pigment epithelium(RPE).The angiogenic behaviors of vascular endothelial cells in vitro depend on forkhead box protein P1(Foxp1),a transcription repressor widely expressed in human and murine tissues during *** this study,we aimed to determine whether loss of Foxp1 affects laser-induced choroidal neovascularization(CNV)in *** Eye-selective deletion of Foxp1 was obtained by crossing Foxp1flox/flox with Six3-Cre *** photocoagulation was delivered to six-to eight-week-old mice to induce *** expression of Foxp1 and Cre was determined by immunofluorescence in cryostat sections of the *** fluorescein angiography(FFA),optical coherence tomography(OCT),and B4 isolectin staining were applied to analyze the leakage,bulge height,and area of CNV lesions,***-choroid tissues were isolated for the determination of VEGF and pigment epithelium derived factor(PEDF)by Western *** Foxp1 was expressed in retinal ganglion cells,RPE,and the choroidal endothelial *** photocoagulation increased the number of Foxp1+-endothelial cells and induced ***3-Cre reduced Foxp1 expression in RPE but not the endothelium,leading to a lower level of VEGF in the ***1 knockout inhibited pathological angiogenesis and vascular leakage of the laser-induced CNV *** Foxp1 regulates the expression of VEGF in the RPE,and inhibition of Foxp1 could potentially be a novel strategy for the prevention and therapy of neovascularization related to AMD.

关键词： Foxp1 Choroidal neovascularization Angiogenesis Laser photocoagulation Age-related macular degeneration

Synthesis,structure,and luminescence properties of melilite Dy^(3+):Lu_(x)CaLa_(0.98-x)Ga_(3)O_(7) phosphors for use in yellow light-emitting devices

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Journal of Rare Earths 2024年第8期42卷 1489-1495,I0003页

作者： Yunyun liu Chuanxin Huang Meng Wang Xihu Wang yan Wang ju Gao School of Opto-Electronic Engineering Zaozhuang UniversityZaozhuang277160China Key Laboratory of Functional Materials and Devices for Informatics of Anhui Educational Institutions Department of PhysicsFuyang Normal UniversityFuyang236037China Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou350002.China

Dy^(3+) and Lu^(3+) co-doped CaLaGa_(3)O_(7) phosphors were prepared via high-temperature solid-phase *** electronic structures of LuxCaLa_(0.98-x)Ga_(3)O_(7) were investigated by the first-principles *** influence of Lu^(3+) on yellow light emission was studied using X-ray diffraction(XRD)and photoluminescence(PL) *** XRD results indicate that compared to Dy^(3+):CaLaGa_(3)O_(7),the cell parameters of Dy^(3+):LuCaLaGa_(3)O_(7) tend to decrease,which is due to the smaller radius of Lu^(3+).When pumped by blue GaN laser diode(LD),the emission peaks of phosphors with different Lu^(3+)doping concentrations in the visible region are similar,with the strongest peak at 574 nm in the yellow light region,which is sensitive to human *** optimal doping concentration of Lu^(3+) is confirmed to be1 at%,when all emission spectra and measured fluorescence lifetimes are taken into ***,the optimal phosphor composition Dy^(3+):Lu_(x)CaLa_(0.98-x)Ga_(3)O_(7)(x=0.01) has an internal quantum efficiency(IQE) of 46.94% and an external quantum efficiency(EQE) of 15.19%.Most notably,the prepared phosphor demonstrates excellent thermal stability and a high activation energy(0.203 eV).In addition,the International Illumination Commission color coordinates of the Dy^(3+):LuxCaLa_(0.98-x)Ga_(3)O_(7) phosphors are in the yellow light *** above analysis indicates that the Dy^(3+):LuxCaLa_(0.98-x)Ga_(3)O_(7)(x=0.001)phosphor has promising application prospects in yellow light-emitting devices.

关键词： Dy^(3+):Lu_(x)CaLa_(0.98-x)Ga_(3)O_(7)phosphors Yellow emission Structure characteristics Luminescent properties Rare earths

Hydrogen production from hydrolysis of NaBH_(4) solution over Co-Fe-B@g-C_(3)N_(4)/NF thin film catalyst

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Rare Metals 2024年第6期43卷 2648-2659页

作者： yan Wang Jia-Xin Ma Jian Ren Di Zhang Feng-yan Xu Ke Zhang Zhong-Qiu Cao Qiu-ju Sun Guo-De li Shi-Wei Wu Hong-Hui Chen College of Chemistry and Chemical Engineering Shenyang Normal UniversityShenyang 110034China Experimental Center Shenyang Normal UniversityShenyang 110034China Hunan Shande Energy Storage New Materials Research Institute limited Company Changde 415000China

In this study,the double loaded Co-Fe-B@g-C_(3)N_(4)/NF(NF:Ni foam)thin film catalysts were prepared for the first time via chemical deposition method at room *** optimizing the reducing agent concentration to 0.9 mol·L^(-1),the as-obtained Co-Fe-B@g-C_(3)N_(4)/NF exhibited the twisted ribbon structure with more distinct three-dimensional hierarchy and the smaller particle size,showing the good catalytic property for the hydrolysis of NaBH_(4)*** H_(2)generation rate of Co-Fe-B@g-C_(3)N_(4)/NF and binary Co-B@g-C_(3)N_(4)/NF under visible light irradiation surpassed the value under natural *** apparent activation energy of Co-Fe-B@g-C_(3)N_(4)/NF(45.0 kJ·mol^(-1))under visible light irradiation was obviously reduced when compared with the natural condition(48.4 kJ·mol^(-1))and binary Co-B@g-C_(3)N_(4)/NF(60.6 kJ·mol^(-1))under visible light ***,the catalytic performance of the optimized Co-Fe-B@g-C_(3)N_(4)/NF thin film catalyst was superior to most of the reported non-noble metal and even noble metal ***,it illustrated that the catalytic H_(2)production performance of Co-Fe-B@g-C_(3)N_(4)/NF thin film was distinctly improved after the introduction of light and multicomponent recombination.

关键词： Sodium borohydride Co-Fe-B@g-C_(3)N_(4)/NF catalyst Chemical deposition Hydrogen production

Fully Nonlinear Equations of Krylov Type on Riemannian Manifolds with Totally Geodesic Boundary

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1293-1307页

作者： li CHEN yan HE Faculty of Mathematics and Statistics Hubei Key Laboratory of Applied MathematicsHubei UniversityWuhan 430000P.R.China

In this paper,we study fully nonlinear equations of Krylov type in conformal geometry on compact smooth Riemannian manifolds with totally geodesic *** prove the a priori estimates for solutions to these equations and ... 详细信息

关键词： The modified Schouten tensor k-convex Hessian type equation