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- ItemZnO Nanoparticles Encapsulated in Nitrogen-Doped Carbon Material and Silicalite-1 Composites for Efficient Propane Dehydrogenation(Amsterdam [u.a.] : Elsevier, 2019) Zhao, Dan; Li, Yuming; Han, Shanlei; Zhang, Yaoyuan; Jiang, Guiyuan; Wang, Yajun; Guo, Ke; Zhao, Zhen; Xu, Chunming; Li, Ranjia; Yu, Changchun; Zhang, Jian; Ge, Binghui; Kondratenko, Evgenii V.Chemistry; Catalysis; Nanoparticles © 2019 The Author(s)Non-oxidative propane dehydrogenation (PDH)is an attractive reaction from both an industrial and a scientific viewpoint because it allows direct large-scale production of propene and fundamental analysis of C-H activation respectively. The main challenges are related to achieving high activity, selectivity, and on-stream stability of environment-friendly and cost-efficient catalysts without non-noble metals. Here, we describe an approach for the preparation of supported ultrasmall ZnO nanoparticles (2–4 nm, ZnO NPs)for high-temperature applications. The approach consists of encapsulation of NPs into a nitrogen-doped carbon (NC)layer in situ grown from zeolitic imidazolate framework-8 on a Silicalite-1 support. The NC layer was established to control the size of ZnO NPs and to hinder their loss to a large extent at high temperatures. The designed catalysts exhibited high activity, selectivity, and on-stream stability in PDH. Propene selectivity of about 90% at 44.4% propane conversion was achieved at 600°C after nearly 6 h on stream. © 2019 The Author(s)
- ItemThe Exploration of Aroyltrimethylgermane as Potent Synthetic Origins and Their Preparation(Amsterdam [u.a.] : Elsevier, 2019) Yuan, Yang; Zhang, Youcan; Chen, Bo; Wu, Xiao-FengThe synthetic utilities of acylgermanes are surprisingly rarely explored compared with their analogues. In this communication, the survey of aroyltrimethylgermane as potent synthetic origins has been studied. A variety of novel chemical transformations have been realized, including using the acylgermane group as a directing group in Rh-catalyzed aromatic C-H alkenylation reaction and Ir-catalyzed aromatic C-H amidation reactions. Additionally, a general approach for acylgermanes preparation has been established as well. The catalytic system proceeds effectively in the presence of Pd(OAc)2/BINOL-based monophosphite (L11) and allows for the straightforward access to a wide range of functionalized acylgermanes in high yields. © 2019 The Author(s)Catalysis; Organic Synthesis; Organic Reaction; Chemical Synthesis © 2019 The Author(s)
- ItemRegulation of Two-Dimensional Lattice Deformation Recovery(Amsterdam [u.a.] : Elsevier, 2019) Liu, Jinxin; Zhou, Lu; Huang, Ke; Song, Xianyin; Chen, Yunxu; Liang, Xiaoyang; Gao, Jin; Xiao, Xiangheng; RĂ¼mmeli, Mark H.; Fu, LeiThe lattice directly determines the electronic structure, and it enables controllably tailoring the properties by deforming the lattices of two-dimensional (2D)materials. Owing to the unbalanced electrostatic equilibrium among the dislocated atoms, the deformed lattice is thermodynamically unstable and would recover to the initial state. Here, we demonstrate that the recovery of deformed 2D lattices could be directly regulated via doping metal donors to reconstruct electrostatic equilibrium. Compared with the methods that employed external force fields with intrinsic instability and nonuniformity, the stretched 2D molybdenum diselenide (MoSe2)could be uniformly retained and permanently preserved via doping metal atoms with more outermost electrons and smaller electronegativity than Mo. We believe that the proposed strategy could open up a new avenue in directly regulating the atomic-thickness lattice and promote its practical applications based on 2D crystals. © 2019 The Author(s)
- ItemThe point charge oscillator: Qualitative and analytical investigations(Vilnius : Vilnius Gediminas Technical University, 2019) Schneider, Klaus R.We study the mathematical model of the point charge oscillator which has been derived by A. Belendez et al. [2]. First we determine the global phase portrait of this model in the Poincare disk. It consists of a family of closed orbits surrounding the unique finite equilibrium point and of a continuum of homoclinic orbits to the unique equilibrium point at infinity. Next we derive analytic expressions for the relationship between period (frequency) and amplitude. Further, we prove that the period increases monotone with the amplitude and derive an expression for its growth rate as the amplitude tends to infinity. Finally, we determine a relation between period and amplitude by means of the complete elliptic integral of the first kind K(k) and of the Jacobi elliptic function cn.
- ItemFood Surplus and Its Climate Burdens(Columbus, Ohio : American Chemical Society, 2016) Hic̀§, Ceren; Pradhan, Prajal; Rybski, Diego; Kropp, Jùˆrgen P.Avoiding food loss and waste may counteract the increasing food demand and reduce greenhouse gas (GHG) emissions from the agricultural sector. This is crucial because of limited options available to increase food production. In the year 2010, food availability was 20% higher than was required on a global scale. Thus, a more sustainable food production and adjusted consumption would have positive environmental effects. This study provides a systematic approach to estimate consumer level food waste on a country scale and globally, based on food availability and requirements. The food requirement estimation considers demographic development, body weights, and physical activity levels. Surplus between food availability and requirements of a given country is considered as food waste. The global food requirement changed from 2,300 kcal/cap/day to 2,400 kcal/cap/day during the last 50 years, while food surplus grew from 310 kcal/cap/day to 510 kcal/cap/day. Similarly, GHG emissions related to the food surplus increased from 130 Mt CO2eq/yr to 530 Mt CO2eq/yr, an increase of more than 300%. Moreover, the global food surplus may increase up to 850 kcal/cap/day, while the total food requirement will increase only by 2%–20% by 2050. Consequently, GHG emissions associated with the food waste may also increase tremendously to 1.9–2.5 Gt CO2eq/yr.
- ItemUnravelling New Processes at Interfaces: Photochemical Isoprene Production at the Sea Surface(Columbus, Ohio : American Chemical Society, 2015) Ciuraru, Raluca; Fine, Ludovic; van Pinxteren, Manuela; D’Anna, Barbara; Herrmann, Hartmut; George, ChristianIsoprene is an important reactive gas that is produced mainly in terrestrial ecosystems but is also produced in marine ecosystems. In the marine environment, isoprene is produced in the seawater by various biological processes. Here, we show that photosensitized reactions involving the sea-surface microlayer lead to the production of significant amounts of isoprene. It is suggested that H-abstraction processes are initiated by photochemically excited dissolved organic matter which will the degrade fatty acids acting as surfactants. This chemical interfacial processing may represent a significant abiotic source of isoprene in the marine boundary layer.