Michigan Technological University

About: Michigan Technological University is a education organization based out in Houghton, Michigan, United States. It is known for research contribution in the topics: Population & Volcano. The organization has 8023 authors who have published 17422 publications receiving 481780 citations. The organization is also known as: MTU & Michigan Tech.

Electronic structure and properties of transition metal-benzene complexes.

Abstract: A comprehensive theoretical study of the geometries, energetics, and electronic structure of neutral and charged 3d transition metal atoms (M) interacting with benzene molecules (Bz) is carried out using density functional theory and generalized gradient approximation for the exchange-correlation potential. The variation of the metal-benzene distances, dissociation energies, ionization potentials, electron affinities, and spin multiplicities across the 3d series in MBz complexes differs qualitatively from those in M(Bz) 2. For example, the stability of Cr(Bz)2 is enhanced over that of CrBz by almost a factor of 30. On the other hand, the magnetic moment of Cr(Bz)2 is completely quenched although CrBz has the highest magnetic moment, namely 6IB ,i n the 3d metal-benzene series. In multidecker complexes involving V2(Bz)3 and Fe2(Bz)3, the metal atoms are found to couple antiferromagnetically. In addition, their dissociation energies and ionization potentials are reduced from those in corresponding M(Bz)2 complexes. All of these results agree well with available experimental data and demonstrate the important role the organic support can play on the properties of metal atoms/clusters.

Synthesis, stabilization and applications of 2-dimensional 1T metallic MoS2

Abstract: 1T MoS2 is metallic octahedral type molybdenum disulfide (MoS2). Compared to the most stable and widely existing triangle prismatic (2H) phase of MoS2, 1T MoS2 possesses distinct electrochemical and electronic properties, such as a high conductivity, abundant active sites both at the edges and on the basal plane for electrochemical catalysis, and enlarged interlayer distance. Due to these merits, the last few years have witnessed a growing amount of interest in both synthesis and application of this unique material. So far, a series of methods have been developed to obtain 1T rich or 1T containing MoS2 and the applications of 1T MoS2 have covered a wide range of areas from electrochemical reactions, photoelectrocatalysis and photodetectors to photothermal agents, energy storage devices, and biosensors. In this article, to obtain a hint of the key reasons for the formation of 1T structured MoS2 and instruct the exploration of more desirable new approaches, the means for fabricating 1T MoS2 that have been reported are carefully classified and compared with a focus on the detailed procedures and the underlying mechanisms. Meanwhile, a full image of the explored applications with 1T MoS2 is provided with an emphasis on the relationship between the properties of 1T MoS2 and the performance and a hope to inspire the development of other potential applications for 1T MoS2. Additionally, the stabilization issue of 1T MoS2 is discussed with a review of the current efforts. The content will be not only helpful for researchers currently working in the related areas but also instructive for the ones new to this field.

Temperature Effects on Kinetics of Microbial Respiration and Net Nitrogen and Sulfur Mineralization

Abstract: Global climate change may impact the cycling of C, N, and S in forest ecosystems because increased soil temperatures could alter rates of microbially mediated processes. We studied the effects of temperature on microbial respiration and net N and S mineralization in surface soils from four northern hardwood forests in the Great Lakes region. Soil samples were incubated in the laboratory at five temperatures (5, 10, 15, 20, and 25°C) for 32 wk. Headspace gas was analyzed for CO2-C at 2-wk intervals, and soils were extracted to determine inorganic N and S. Cumulative respired C and mineralized N and S increased with temperature at all sites and were strongly related (r2 = 0.67 to 0.90, significant at P = 0.001) to an interaction between temperature and soil organic C. Production of respired C and mineralized N was closely fit by first-order kinetic models (r2 > 0.94, P = 0.001), whereas mineralized S was best described by zero-order kinetics. Contrary to common assumptions, rate constants estimated from the first-order models were not consistently related to temperature, but apparent pool sizes of C and N were highly temperature dependent. Temperature effects on microbial respiration could not be accurately predicted using temperature-adjusted rate constants combined with a constant pool size of labile C. Results suggest that rates of microbial respiration and the mineralization of N and S may be related to a temperature-dependent constraint on microbial access to substrate pools. Simulation models should rely on a thorough understanding of the biological basis underlying microbially mediated C, N, and S transformations in soil.

Searches for anisotropies in the arrival directions of the highest energy cosmic rays detected by the Pierre Auger Observatory

Abstract: Fil: Almela, Daniel Alejandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Instituto de Tecnologias en Deteccion y Astroparticulas; Argentina

Efficient Visible Light Photocatalytic CO2 Reforming of CH4

Abstract: The large energy requirement of CO2 reforming of methane (CRM) has obstructed its application. Solar energy is a solution for the issue. Different from efficient photocatalytic splitting of water, photocatalysis for CRM exhibits a very low efficiency and employs only ultraviolet (UV) light. This letter reports an efficient visible-light photocatalytic CRM by combining Pt/black TiO2 catalyst with light-diffuse-reflection-surface. Under visible light illumination by filtering UV light from AM 1.5G sunlight, H2 and CO yields reached 71 and 158 mmol/h/gcat, with a quantum efficiency of 32.3% at 550 °C, and 129 and 370 mmol/h/gcat, with a quantum efficiency of 57.8% at 650 °C. Those yields are 3 orders of magnitude larger than the reported values.