Results 51 to 60 of about 130,756 (301)

Biogeochemistry of Stable Carbon Isotopes [PDF]

, 1969
In 1947, in his classical paper on the thermodynamic properties of isotopic substances, H. C. Urey [1] laid the foundation of modern isotope geochemistry. At the same time, A. O. Nier [2] designed a new mass spectrometer which allowed the measurement of small differences in isotope abundance ratios. A modification in the Nier-type mass spectrometer and
openaire   +1 more source

Main controls on the stable carbon isotope composition of speleothems [PDF]

Geochimica et Cosmochimica Acta, 2020
The climatic controls on the stable carbon isotopic composition (d13C) of speleothem carbonate are less often discussed in the scientific literature in contrast to the frequently used stable oxygen isotopes. Various local processes influence speleothem d13C values and confident and detailed interpretations of this proxy are often complex.
Fohlmeister, Jens, Voarintsoa, Ny Riavo G., Lechleitner, Franziska A., Boyd, Meighan, Brandtstätter, Susanne, Jacobson, Matthew J., L. Oster, Jessica   +6 more
openaire   +5 more sources

Auto‐Generated Valence States in Electrocatalysts for Boosting Oxygen and Hydrogen Evolution Kinetics in Alkaline Water/Alkaline Seawater/Simulated Seawater/Natural Seawater

Advanced Functional Materials, EarlyView.
This review systematically highlights the latest achievements in mixed‐valence states relevant to hydrogen and oxygen evolution reactions, providing essential insights into future directions and methods for large‐scale practical implementation. This critical review is expected to provide an overview of recent advancements in diverse valence‐state metal
Jitendra N. Tiwari, Gokul Bhaskaran, Krishan Kumar, Yun Suk Huh, Young‐Kyu Han   +4 more
wiley   +1 more source

Hominin palaeoecology in Late Pliocene Malawi : first insights from isotopes (13C, 18O) in mammal teeth [PDF]

, 2011
Carbon-13 and oxygen-18 abundances were measured in large mammal skeletal remains (tooth enamel, dentine and bone) from the Chiwondo Beds in Malawi, which were dated by biostratigraphic correlation to ca. 2.5 million years ago.
Bocherens, Herv, Kullmer, Ottmar, Sandrock, Oliver, Schrenk, Friedemann   +3 more
core   +2 more sources

Shaping Ti3C2 MXene Nanospheres for Precision Near‐Infrared Photothermal Therapy

Advanced Functional Materials, EarlyView.
In this study, we report producing spherical MXenes via fs laser fragmentation of Ti3C2 flakes in liquid medium. The nanoparticles demonstrated pronounced light absorption and high photothermal conversion efficiencies of 68% and 63% under heating with NIR‐I and NIR‐II lasers, respectively.
Julia S. Babkova, Ivan V. Zelepukin, Konstantin G. Shevchenko, Gleb V. Tikhonowski, Lyubov V. Gorelik, Anton A. Popov, Anna S. Sogomonyan, Alina Yu. Kapitannikova, Ivan S. Kazantsev, Dmitry V. Dyubo, Daria A. Panova, Daniil I. Tselikov, Anton A. Minnekhanov, Aziz B. Mirkasymov, Georgy A. Ermolaev, Alexander V. Syuy, Gleb I. Tselikov, Aleksey V. Arsenin, Andrei V. Kabashin, Kostya S. Novoselov, Sergey M. Deyev, Valentyn S. Volkov   +21 more
wiley   +1 more source

Sulphur-isotope compositions of pig tissues from a controlled feeding study [PDF]

, 2017
Sulphur-isotope determinations are becoming increasingly useful for palaeodietary reconstruction, but knowledge of isotopic discrimination between diet and various tissues remains inadequate. In this study, we explore the sensitivity of δ34Stissue values
Evershed, Richard P., Lewis, Jamie, Miller, Bevis, Newton, Jason, Stewart, Alan, Tarlton, John F., Webb, Emily C.   +6 more
core   +2 more sources

Stable isotopes in stratospheric carbon monoxide [PDF]

, 2021
The isotopes of an element provide a wealth of information for the chemistry and transport of trace gases in the atmosphere. In this work, the isotope composition of carbon and oxygen in carbon monoxide is used to gain new insights on transport and chemistry related to methane oxidation in the stratosphere.
openaire   +1 more source

Engineering Hydrogen‐Down Water Configurations for Ampere‐Level Electrochemical CO2 Reduction to Formate

Advanced Functional Materials, EarlyView.
Electrochemical CO2 reduction (ECR) to formate is a promising route for sustainable chemical production. Herein, we report the synthesis catalysed byBi‐HfO2@C. The AIMD simulations, DFT calculations, and in situ SEIRAS measurements show that the modification of HfO2 on the Bi surface steers the interfacial water to adopt a favorable hydrogen‐down (OH2↓)
Xiao‐Dong Guo, Shao‐Qing Liu, Jia‐Yi Wu, Qi‐Rui Wen, Xiaoxiao Wei, Shu‐Wen Wu, Xian‐Zhu Fu, Jing‐Li Luo   +7 more
wiley   +1 more source

Source apportionment of polycyclic aromatic hydrocarbons and black carbon at the western coastal areas of the Yellow Sea based on isotopic signatures

Ecological Indicators, 2021
The stable and radioactive isotopes (δ13C, Δ14C and δ2H) of black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) in the sediment from the western coastal areas of the Yellow Sea (i.e.
Yipeng Wang, Rui Zhang, Yuehua Song, Fan Zhang, Junjie Hu, Tiegang Li, James Russell, Xiaoxiao Yu, Jialei Yang, Zhiyong Liu, Yu Li, Minglei Guan, Qi Han, Guihong Li   +13 more
doaj   +1 more source

Halite and stable chlorine isotopes in the Zag H3-6 breccia [PDF]

, 2004
Zag is an H3-6 chondrite regolith breccia within which we have studied 14 halite grains ?3mm. The purity of the associated NaCl-H2O brine is implied by freezing characteristics of fluid inclusions in the halite and EPMA analyses together with a lack of ...
Banks, D.A., Bridges, J.C., Grady, M.M., Smith, M.   +3 more
core   +1 more source