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Enhancing reversible hydrogen storage performance of 2LiBH4–MgH2 via in-situ building heterogeneous nucleation sites

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Rare Metals 2024年第9期43卷 4367-4376页

作者： Wei Chen Ya-Hui Sun Tian Xu Xue-Bin Yu Guang-Lin Xia department of Materials Science Fudan University

2LiBH4-MgH2composite is one of the most attractive reactive hydride composites with a theoretic hydrogen capacity of 10.8 wt%.However,the large nucleation restriction of MgB2during the second step of dehydrogenation results in sluggish hydrogen storage kinetics and high operating temperature,which hinders its practical application as on-board hydrogen storage ***,Al3Ti doped Al nanoparticles （AT NPs） are prepared by a facile chemical reduction reaction to improve the hydrogen storage performance of *** the initial H2desorption process,MgAlB4and TiB2that have identical crystal structure and low d-value mismatch with MgB2resulting from the reaction between AT NPs and 2LiBH4-MgH2composite serve as effective nucleation sites for the formation of *** a result,the apparent activation energy of the two-step H2desorption of AT NPs doped 2LiBH4-MgH2composite are notably decreased to （110.0±5.9） and（119.6±1.4） kJ·mol-1,which is 55.5 and 33.5 kJ·mol-1lower than that of the undoped *** importantly,a reversible hydrogen storage capacity of 9.2 wt%after 10cycles of H2desorption and adsorption could be achieved,corresponding to a capacity retention rate of 99%.The building of reactive bimetallic catalyst towards in situ formation of heterogeneous nucleation sites provides a new strategy for improving the hydrogen storage performance of reactive hydride composites.

关键词： Catalytic effects Heterogeneous nucleation Reactive hydride composites Reversible hydrogen storage

Comparing 11 early warning scores and three shock indices in early sepsis prediction in the emergency department

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World Journal of Emergency Medicine 2024年第4期15卷 273-282页

作者： Rex Pui Kin Lam Zonglin Dai Eric Ho Yin Lau Carrie Yuen Ting Ip Ho Ching Chan Lingyun Zhao Tat ChiTsang Matthew Sik Hon Tsui Timothy Hudson Rainer department of Emergency Medicine School of Clinical MedicineLi Ka Shing Faculty of Medicinethe University of Hong KongHong KongChina School of Public Health Li Ka Shing Faculty of Medicinethe University of Hong KongHong KongChina Accident and Emergency department Queen Mary HospitalHong KongChina

BACKGROUND:This study aimed to evaluate the discriminatory performance of 11 vital sign-based early warning scores(EWSs)and three shock indices in early sepsis prediction in the emergency department(ED).METHODS:We performed a retrospective study on consecutive adult patients with an infection over 3 months in a public ED in Hong *** primary outcome was sepsis(Sepsis-3 definition)within 48 h of ED *** c-statistics and the DeLong test,we compared 11 EWSs,including the National Early Warning Score 2(NEWS2),Modified Early Warning Score,and Worthing Physiological Scoring System(WPS),etc.,and three shock indices(the shock index[SI],modified shock index[MSI],and diastolic shock index[DSI]),with Systemic Inflammatory Response Syndrome(SIRS)and quick Sequential Organ Failure Assessment(qSOFA)in predicting the primary outcome,intensive care unit admission,and mortality at different time ***:We analyzed 601 patients,of whom 166(27.6%)developed ***2 had the highest point estimate(area under the receiver operating characteristic curve[AUROC]0.75,95%CI 0.70-0.79)and was significantly better than SIRS,qSOFA,other EWSs and shock indices,except WPS,at predicting the primary ***,the pooled sensitivity and specificity of NEWS2≥5 for the prediction of sepsis were 0.45(95%CI 0.37-0.52)and 0.88(95%CI 0.85-0.91),*** discriminatory performance of all EWSs and shock indices declined when used to predict mortality at a more remote time ***:NEWS2 compared favorably with other EWSs and shock indices in early sepsis prediction but its low sensitivity at the usual cut-off point requires further modification for sepsis screening.

关键词： Sepsis Emergency department Clinical prediction rule Early warning score Shock index

Existence and asymptotics of normalized solutions for the logarithmic Schr?dinger system

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Science China Mathematics 2024年第9期67卷 2019-2048页

作者： Qian Zhang Wenming Zou department of Mathematical Sciences Tsinghua University

This paper is concerned with the following logarithmic Schr?dinger system:■where Ω=RNor Ω?RN（N≥3） is a bounded smooth domain,and ωi∈R,μi,ρi> 0 for i=1,***,p,q≥1,and 2≤p+q≤2*,where 2*:=2N/N-2. By using a Gagliardo-Nirenberg inequality and a careful estimation of u log u2,firstly,we provide a unified proof of the existence of the normalized ground state solution for all 2≤p+q ≤2*.Secondly,we consider the stability of normalized ground state ***,we analyze the behavior of solutions for the Sobolev-subcritical case and pass to the limit as the exponent p+q approaches 2*.Notably,the uncertainty of the sign of u log u2in（0,+∞） is one of the difficulties of this paper,and also one of the motivations we are interested *** particular,we can establish the existence of positive normalized ground state solutions for the Brézis-Nirenberg type problem with logarithmic perturbations（i.e.,p+q=2*）.In addition,our study includes proving the existence of solutions to the logarithmic type Bréis-Nirenberg problem with and without the *** ∫Ω|ui|2dx=ρi（i=1,2） by two different methods,*** results seem to be the first result of the normalized solution of the coupled nonlinear Schr?dinger system with logarithmic perturbations.

关键词： logarithmic Schrödinger system Brézis-Nirenberg problem normalized solution existence and stability behavior of solutions

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Numerical analysis of moving train induced vibrations on tunnel,surrounding ground and structure

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 179-192页

作者： Swati Srivastav Sowmiya Chawla Swapnil Mishra department of Applied Geophysics Indian Institute of Technology(ISM)Dhanbad 826004India department of Civil Engineering Indian Institute of Technology(ISM)Dhanbad 826004India department of Mining Engineering Indian Institute of Technology(ISM)Dhanbad 826004India

This study is focused on the effect of vibration induced by moving trains in tunnels on the surrounding ground and structures.A three-dimensional finite element model is established for a one-track railway tunnel and an adjacent twelve-storey building frame by using commercial software Midas GTS-NX(2019)and Midas *** study considered the moving load effect of a complete train,which varies with space as well as with *** effect of factors such as train speed,overburden pressure on the tunnel and variation in soil properties are studied in the time *** a result,the variations in horizontal and vertical acceleration for two different sites,i.e.,the free ground surface(without structure)and the area containing the structure,are ***,the displacement pattern of the raft foundation is plotted for different train *** lower speeds,the heaving phenomenon is negligible,but as the speed increases,both the heaving and differential settlement increase in the *** study demonstrates that the effect of moving train vibrations should be considered in the design of new nearby structures and proper ground improvement should be considered for existing structures.

关键词： moving train load tunnels vibration effect finite element method(FEM) wave propagation

Assessment of the implementation status of best available techniques for cleaner production in the textile industry

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 133-148页

作者： Mehmet Eren Yaman Emrah Ozturk Ulku Yetis Mehmet Kitis department of Environmental Engineering Suleyman Demirel UniversityIsparta 32260Turkey department of Environmental Protection Technologies Isparta University of Applied SciencesIsparta 32200Turkey department of Environmental Engineering Middle East Technical UniversityAnkara 06800Turkey

The draft Integrated Pollution Prevention and Control(IPPC)regulation mandates compliance with best available techniques(BATs)for textile manufacturers.A study in Turkish textile facilities,covering 56 units across four sub-sectors,assessed the status of 488 BATs through on-site visits and *** aim was to gauge the sector’s adherence to *** findings revealed that 37% of surveyed BATs were fully implemented,rising to 88% when considering potential future *** suggests a strong industry inclination toward adopting BATs for cleaner production and *** study highlighted significant BAT-related investments in the textile sector,driven by environmental concerns,regulations,customer demands,resource efficiency,competition,and cost-benefit ***,the study results also indicated that there is still much work to do for the implementation of some *** was found that 60 BATs had lower implementation ratios(IR:0%-43%).Lower IR values for these BATs are mainly due to factors like specificity,high costs,long payback periods,operational difficulties,limited expertise,space constraints,customer requirements,quality concerns,operational issues,and sector-specific *** study recommends similar assessments in other European industrial sectors to evaluate compliance with mandatory BATs outlined in the Industrial Emissions *** insights from this study on the Turkish textile sector can serve as a valuable guide for future evaluations.

关键词： Best available techniques(BAT) Cleaner production Green Deal Integrated Pollution Prevention and Control(IPPC) Textile sector

Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： David J.Bottjer department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Neutral and metallic *** and semiconducting surface layer in acceptor doped CeO_(2)

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 795-802页

作者： Ilan Riess Physics department Technion IITHaifa 3200003Israel

The monomolecular surface layer of acceptor doped CeO_(2) may become neutral and metallic or charged and *** is revealed in the theoretical analysis of the oxygen pressure dependence of the surface defects concentration in acceptor doped ceria with two different dopant types and operated under different oxygen *** published experimental data for highly reduced Sm0.2Ce0.8O1.9-x(SDC)containing a fixed valence dopant Sm3+are very different from those published for Pr0.1Ce0.9O_(2)-x(PCO) with the variable valence dopant Pr4+/Pr3+being reduced under milder *** theoretical analysis of these experimental results fits very well the experimental results of SDC and *** leads to the following predictions:the highly reduced surface of SDC is metallic and neutral,the metallic surface electron density of state is gs=0.9×10^(38)J-1·m^(-2)(1.4×1015eV^(-1)·cm^(-2)),the electron effective mass is meff,s=3.3me,and the phase diagram of the reduced surface has theα(fcc)structure as in the *** PCO a double layer is predicted to be formed between the surface and the bulk with the surface being negatively charged and *** surface of PCO maintains high Pr^(3+) defect concentration as well as relative high oxygen vacancy concentration at oxygen pressures higher than in the *** reasons for the difference between a metallic and semiconducting surface layer of acceptor doped CeO_(2) are reviewed,as well as the key theoretical considerations applied in coping with this *** that we make use of the experimental data and theoretical analysis available for acceptor doped ceria.

关键词： CeO_(2) surface defects metallic surface oxide reduction Sm doped CeO_(2) Pr doped CeO_(2)

Observational signatures of rotating black holes in the semiclassical gravity with trace anomaly

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Chinese Physics C 2024年第8期48卷 257-265页

作者： Zhenyu Zhang Yehui Hou Minyong Guo department of Physics Peking UniversityBeijing 100871China department of Physics Beijing Normal UniversityBeijing 100875China

In a recent work by Fernandes[***.D 108(6),L061502(2023)],an exact stationary and axisymmetric solution was discovered in semiclassical gravity with type-A trace *** was identified as a quantum-corrected version of the Kerr black *** this study,we explore the observational signatures of this black hole *** investigation reveals that prograde and retrograde light rings exist,whose radii increase monotonically with the coupling parameterα.Whenαis negative,the shadow area for the quantum-corrected black hole is smaller than that of the Kerr black hole,whereas whenαis positive,the area is *** a near-extremal black hole,its high-spin feature(the NHEKline)is found to be highly susceptible to disruption byα.Furthermore,we discuss the images of the quantum-corrected black hole in the presence of a thin accretion disk and compare them to those of the Kerr black *** study highlights the importance of near-horizon emission sources in detecting the effects of quantum corrections by black hole images.

关键词： quantum-corrected rotating black hole light rings black hole shadow

Structural,optical,electrical,and dielectric relaxation properties of rare earth containing sodium bismuth titanate Na_(0.5)Bi_(0.5)TiO_(3) perovskite:Effect of ionic radius

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Journal of Rare Earths 2024年第2期42卷 383-391,I0006页

作者： Rajdip Roy Abhigyan Dutta department of Physics The University of BurdwanBurdwan713104India

The main focus of this work is to study the effect of the ionic radius of different rare earth dopant cations RE^(3+)(RE=La,Sm,Dy,and Ho) on structural and various physical properties of sodium bismuth titanate(Na_(0.5)B_(0.5)TiO_(3),NBT) based perovskite *** X-ray diffraction data indicate the successful formation of the rhombohedral phase(space group R3c) of NBT nano perovskite incorporated with various rare earth ions in *** lattice parameters were found to increase linearly with the ionic radius of the dopant *** ionic radii and atomic mass of rare earth dopants appear to be essential factors in the grain growth of the prepared *** grain growth results in better crystallinity of the sample by reducing the microstrain with the increase of dopant ionic *** emission scanning electron microscopy and energy-dispersive X-ray spectra confirm the prepared compositions' phase purity and *** UV-Vis spectra reveal that La-doped NBT composition exhibits the lowest optical band gap,which unfolds the application of NBT-based perovskite as photoactive *** ac conductivity and complex impedance spectra unveil that the composition with the largest ionic radius,i.e.,La-doped NBT compound,exhibits the highest dc and bulk conductivity with the lowest activation *** frequency-dependent dielectric data follows Havriliak-Negami(HN) formalism and non-Debye type relaxation *** also indicate that La-doped NBT composition exhibits the highest dielectric strength ***,this study first elaborates that the increasing ionic radius of the rare earth dopant cation in the Bi-site of NBT perovskite improves its microstructural,optical,and electrical properties.

关键词： Rare earth doped NBT Microstructural analysis Optical band gap AC Conductivity Dielectric relaxation Rare earths