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The effect of topographic density variations on the geoid and orthometric heights in Hong Kong

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geodesy and geodynamics 2024年第5期15卷 495-503页

作者： Albertini Nsiah Ababio department of Land Surveying and geo-Informatics Hong Kong Polytechnic UniversityHong KongChina

Utilizing the adopted average topographic density of 2670 kg/m^(3)in the reduction of gravity anomalies introduces errors attributed to topographic density variations,which consequently affect geoid modeling ***,the mean gravity along the plumbline within the topography in the definition of Helmert orthometric heights is computed approximately by applying the Poincar e-Prey gravity reduction where the topographic density variations are *** Helmert orthometric heights of benchmarks are then affected by *** errors could be random or systematic depending on the specific geological setting of the region where the leveling network is physically established and/or the geoid model is *** example of systematic errors in orthometric heights can be given for large regions characterized by sediment or volcanic deposits,the density of which is substantially lower than the adopted topographic density used in Helmert's definition of *** same applies to geoid modeling *** this study,we investigate these errors in the Hong Kong territory,where topographic density is about 20%lower than the density of 2670 kg/m^(3).We use the digital rock density model to estimate the effect of topographic density variations on the geoid and orthometric *** results show that this effect on the geoid and Helmert orthometric heights reach maxima of about 2.1 and 0.5 cm,*** results provide clear evidence that rock density models are essential in physical geodesy applications involving gravimetric geoid modeling and orthometric height determination despite some criticism that could be raised regarding the reliability of these density ***,in regions dominated by sedimentary and igneous rocks,the geological information is essential in these applications because topographic densities are substantially lower than the average density of 2670 kg/m^(3),thus introducing large systematic errors in geoid and orthometric

关键词： Rock density geoid Topography Heights Leveling network

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Impact of inorganic and organic pollutants from a Belgian wastewater treatment plant on adjacent surface and groundwaters

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 75-90页

作者： Mingyue Luo Yiqi Su Delphine Jenny Vandeputte Yuwei Jia Guanlei Li Willy Baeyens Marijke Huysmans Marc Elskens Yue Gao Analytical Environmental and Geo-Chemistry Department(AMGC)Vrije Universiteit Brussel(VUB)Pleinlaan 21050 BrusselsBelgium hydrology and Hydraulic Engineering(HYDR) Vrije Universiteit Brussel(VUB)Pleinlaan 21050 BrusselsBelgium

Under the pressure of global droughts and water shortage,it is essential to evolve toward a sustainable and robust water *** possible avenue is the maximum reuse of treated wastewater,but the quality of which determines its ***,inorganic(Cd,Pb,Cr,Ni,Cu,and As)and organic(xenoestrogens and polycyclic aromatic contaminants,PACs)contaminants were monthly monitored in an effluent of the wastewater treatment plant(WWTP),the surrounding surface waters and the local groundwater in *** and particulate concentrations of inorganic contaminants in these water bodies were *** addition,Diffusive Gradients in Thin-films(DGT)was used in situ to obtain bioavailable metal *** the WWTP effluent and surface waters,only Ni exceeds the Annual Average-Environmental Quality Standard(AA-EQS),while in the groundwater,dissolved As was the predominant ***,in the surface and effluent waters the highest lability degrees were observed for Cd and *** concentrations of these metal species in the effluent water were lower than in the other water ***-organic pollutants,xenoestrogens and PACs were analyzed by dual Estrogen and Aryl hydrocarbon Receptor-Chemical Activated LUciferase gene eXpression(ER&AhR-CALUX)*** the annual averaged(AA)bioequivalent concentration of E2(0.18 ng/L)is below the AA-EQS standard(0.4 ng/L),and the bioequivalent concentration of benzo[a]pyrene never exceeded the maximum admissible concentration(MAC),the reclamation and reuse of treated wastewater for groundwater replenishment and agricultural irrigation should pose no environmental problems,at least in a short-term.

关键词： Metal contaminants DGT Labile metal fractions ERE/AhR-CALUX BEQ Xenoestrogens and polycyclic aromatic contaminants

Sensing nanoscale electromagnetic forces when the heat is on

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National Science Review 2024年第7期11卷 64-65页

作者： Eric O.Potma department of chemistry University of California

In scanning probe microscopy(SPM),a sharp tip scans across a sample to produce an image with nanometer-scale resolution or better. SPM contrast is derived from the physical interplay between the tip and the sample. A special class of SPM techniques measures forces when the tip–sample junction is illuminated by an external light source. Photo-induced forces can be sensitive to the optical properties of the sample, thus enabling nanoscale imaging with spectroscopic,material-specific contrast.

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Charting the course to solid-state dual-ion batteries

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Carbon Energy 2024年第3期6卷 132-177页

作者： Habtom D.Asfaw Antonia Kotronia Nuria Garcia-Araez Kristina Edström Daniel Brandell department of chemistry Ångström LaboratoryUppsala UniversityUppsalaSweden department of chemistry University of SouthamptonSouthamptonUK

An electrolyte destined for use in a dual-ion battery(DIB)must be stable at the inherently high potential required for anion intercalation in the graphite electrode,while also protecting the Al current collector from anodic dissolution.A higher salt concentration is needed in the electrolyte,in comparison to typical battery electrolytes,to maximize energy density,while ensuring acceptable ionic conductivity and operational *** recent years,studies have demonstrated that highly concentrated organic electrolytes,ionic liquids,gel polymer electrolytes(GPEs),ionogels,and water-in-salt electrolytes can potentially be used in *** can help reduce the use of solvents and thus lead to a substantial change in the Coulombic efficiency,energy density,and long-term cycle life of ***,GPEs are suited to manufacture compact DIB designs without separators by virtue of their mechanical strength and electrical *** this review,we highlight the latest advances in the application of different electrolytes in DIBs,with particular emphasis on GPEs.

关键词： anion intercalation concentrated electrolytes dual-ion battery graphite ionic liquids polymer electrolyte

Non-innocent partners:bias distribution between photoanodes and cathodes in photoelectrochemical overall water-splitting cells

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National Science Review 2024年第6期11卷 88-89页

作者： Wei Li Dunwei Wang department of chemistry Merkert Chemistry Center Boston College

Photoelectrochemical (PEC) overall water splitting (OWS) represents a highly promising strategy to directly harvest solar energy and store it in the form of fuels,offering unique benefits such as mitigating issues con...

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Silvery fullerene in Ag102 nanosaucer

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National Science Review 2024年第7期11卷 158-167页

作者： Zhi Wang Yuchen Wang Chengkai Zhang Yan-Jie Zhu Ke-Peng Song Christine M.Aikens Chen-Ho Tung Di Sun School of chemistry and Chemical Engineering Shandong University department of chemistry Kansas State University

Despite the discovery of a series of fullerenes and a handful of noncarbon clusters with the typical topology of Ih-C60, the smallest fullerene with a large degree of curvature, C20, and its other-element counterparts are difficult to isolate experimentally. In coinage metal nanoclusters（NCs）, the first all-gold fullerene, Au32, was discovered after a long-lasting pursuit, but the isolation of similar silvery fullerene structures is still challenging. Herein, we report a flying saucer-shaped 102-nuclei silver NC（Ag102） with a silvery fullerene kernel of Ag32, which is embraced by a robust cyclic anionic passivation layer of（KPO4）10. This Ag32kernel can be viewed as a non-centered icosahedron Ag12encaged into a dodecahedron Ag20, forming the silvery fullerene of Ag12@Ag20. The anionic layer（KPO4）10is located at the interlayer between the Ag32kernel and Ag70shell, passivating the Ag32silvery fullerene and templating the Ag70shell. The ~tBuPhS-and CF3COO-ligands on the silver shell show a regioselective arrangement with the 60 ~tBuPhS-ligands as expanders covering the upper and lower of the flying saucer and 10 CF3COO-as terminators neatly encircling the edges of the structure. In addition, Ag102 shows excellent photothermal conversion efficiency（η） from the visible to near-infrared region（η = 67.1% ± 0.9% at 450 nm, 60.9% ± 0.9% at 660 nm and 50.2% ± 0.5% at 808 nm）, rendering it a promising material for photothermal converters and potential application in remote laser ignition. This work not only captures silver kernels with the topology of the smallest fullerene C20, but also provides a pathway for incorporating alkali metal（M） into coinage metal NCs via M-oxoanions.

关键词： silvery fullerene >Ag102 nanosaucer cyclic anionic passivation layer photothermal conversion DFT calculation

Increasing polymer scission rate by tying an overhand knot

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Science China chemistry 2024年第11期67卷 3498-3499页

作者： Yuheng Hu Jennifer T.Ou Jim Y.Huang Yuanning Feng department of chemistry and Biochemistry The University of Oklahoma

Similar to the phenomenon of knotted ropes in life, knotted climbing ropes will reduce their strength due to knots. Although computer simulations [1], theoretical speculation[2,3], and intuition [3] suggest that similar processes may occur at the nanoscale, this hypothesis has not been experimentally proven before. With the increasing maturity of molecular recognition and self-assembly, a research communication by Leigh et al. [4] published in Nature chemistry introduced a molecular overhand knot into a polymer to study its effect on the scission rate of the polymer chain under tension.

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Solute flow and particle transport in aquatic ecosystems: A review on the effect of emergent and rigid vegetation

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Environmental Science and Ecotechnology 2024年第5期21卷 77-91页

作者： Judy Q.Yang St.Anthony Falls Laboratory Department of CivilEnvironmentaland Geo-EngineeringUniversity of Minnesota Twin CitiesMNUSA

In-channel vegetation is ubiquitous in aquatic environments and plays a critical role in the fate and transport of solutes and particles in aquatic *** studies have advanced our understanding of the role of vegetation in solute flow and particle transport in aquatic *** review summarizes these papers and discusses the impacts of emergent and rigid vegetation on the surface flow,the advection and dispersion of solutes,suspended load transport,bedload transport,and hyporheic *** two competing effects of emergent vegetation on the above transport processes are *** the one hand,emergent vegetation reduces mean flow velocity at the same surface slope,which reduces mass *** the other hand,at the same mean flow velocity,vegetation generates turbulence,which enhances mass *** understanding of these two competing effects and predictive equations derived from laboratory experiments are *** equations for the mean flow velocity and turbulent kinetic energy inside an emergent vegetation canopy are derived based on force and energy *** impacts of emergent vegetation on the advection-dispersion process,the suspended load and bedload transport,and the hyporheic exchange are *** impacts of other vegetation-related factors,such as vegetation morphology,submergence,and flexibility,are briefly *** role of vegetation in transporting other particles,such as micro-and macro-plastics,is also briefly ***,suggestions for future research directions are proposed to advance the understanding of the dynamic interplays among natural vegetation,flow dynamics,and sedimentary processes.

关键词： transport load flow

Terminal-selective C（sp3）–H borylation of unbranched alkanes enabled by intermolecular radical sampling and LMCT photocatalysis

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National Science Review 2024年第5期11卷 96-98页

作者： Zhexuan Lei Jie Wu department of chemistry National University of Singapore

The selective functionalization of C（sp3）–H bonds with subtle differences in alkanes is highly sought after due to its atom-and step-efficiency. The activation of C（sp3）–H bonds through hydrogen atom transfer （HAT） has been extensively exploited to produce a valueadded product from unfunctionalized material [1,2].

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