The directional upgrading from lignite liquefied crude oils to value-added oxygenated chemicals is an important pathway to optimize the clean non-fuel conversion system of lignite. However, O-containing group diversities and substituent differences make it difficult for such crude oils to be converted to fatty alcohols by simple hydrogenation. In view of this, a two-step cascade extraction system using the ternary mixed solution (petroleum ether/carbon disulfide, methanol, and water) was designed in this paper, and used for rapid enrichment of O-containing portions in Dongming lignite ethanolysis-derived crude oil to obtain O-rich oil (SPE). In addition, a Ni-based LaMgAlOx composite solid base, Ni@La30BMO, modified by doping La was also constructed and used for the directional upgrading of O-rich oil (SPE) to fatty alcohols, especially alkyl cyclanols. The results show that Ni@La30BMO has excellent aromatic ring hydrogenation, >C-O- bridged bond cleavage, and >CalOH retention properties, which are attributed to the texture property improvement of La30BMO by doping La and the strong Ni-La30BMO interaction. Benzyloxybenzene can be selectively converted to methylcyclohexane and cyclohexanol over Ni@La30BMO. >CalOH retention is related to the synergistic transfer of H···H and δ+H···Hδ- after H2 activation and the inhibition of H· and H+ transfer over basic sites modified by La. In addition, the total proportion of O-containing species in SPE obtained by rapid enrichment is 81.3%, and arenols (65.1%) are dominant. After selective hydrofining, the proportion of fatty alcohols in refined oil (CHSPE) increased significantly from 4.1 to 79.0%, and that of alkyl cyclanols reached 74.8%. Overall, Ni@La30BMO is a potential catalyst for the conversion of complex lignite-based crude oils into fine oxygenated chemicals of fatty alcohols, especially alkyl cyclanols. The step-wise directional conversion from complex derived crude oils to simple enriched oils and/or refined oils is a new idea worth considering.
In this paper, 3 km Moderate resolution Imaging Spectroradiometer (MODIS) aerosol products over Xuzhou and the surrounding area, including Jiangsu, Anhui, Henan and Shandong provinces in China, from July, 2002 to December, 2015 are collected and validated by the ground-based measured data from Xuzhou-CUMT site of Aerosol Robotic Network (AERONET). The validation result shows that the correlation coefficient of aerosol optical depth (AOD) between MODIS and AERONET data is 0.86 and the regression equation is y = 1.06× + 0.06. The monthly and seasonal average of 3 km MODIS AOD are calculated and charted. The results show that AOD in Xuzhou area is highest in summer and lowest in winter. The average of monthly AOD is about 0.82. After 2008 Beijing Olympic Games, AOD in Xuzhou increases again. Therefore, the sustained efforts should be made to improve air quality in Xuzhou area.
Abstract Die enantioselektive C−H‐Aktivierung hat sich zu einem transformativen Werkzeug für den effizienten Aufbau chiraler Moleküle entwickelt. Trotz großer Fortschritte in der Rhodium‐ und Palladiumkatalyse hat sich die ruthenium(II)‐katalysierte enantioselektive C−H‐Aktivierung bisher jedoch als weitgehend herausfordernd erwiesen. Im Gegensatz dazu berichten wir nun über eine ruthenium(II)‐katalysierte hochregio‐, diastereo‐ und enantioselektive C−H‐Alkylierung. Als Schlüssel zum Erfolg wurden C2‐symmetrischen chiralen Imidazolidincarbonsäuren (CICAs), die leicht in einer Eintopfreaktion hergestellt werden können, als hochwirksame chirale Liganden identifiziert. Dieses Ruthenium/CICA‐System ermöglichte die effiziente Installation der zentralen und axialen Chiralität und verfügte über ausgezeichnete verzweigte bis lineare Verhältnisse mit im Allgemeinen >20 : 1 dr und bis zu 98 : 2 er. Experimentelle und computerchemische mechanistische Studien wurden durchgeführt, um die Wirkungsweise des Katalysators zu entschlüsseln.
This article presents the initial development of a biomass sensor to monitor the growth of macroalgae (seaweeds) in the Integrated Multi-Trophic Aquaculture (IMTA) at Harbor Branch Oceanographic Institute at Florida Atlantic University. The sensor utilizes a combined optical/acoustic means to quantify the seaweed biomass. Such configuration ensures the sensor providing robust coverage under different ambient conditions and biomass densities. After the biomass sensor's performance has been validated in the lab environment, we deployed the sensor at the macroalgal seaweed cultivation raceway to quantify the seaweed density. The data processing procedures are documented, and the field test results are presented. Finally, the advantages and disadvantages of this approach and future application of the sensor to drive a machine learning-based prediction biomass model are discussed.
Enantioselective C-H activation has surfaced as a transformative toolbox for the efficient assembly of chiral molecules. However, despite of major advances in rhodium and palladium catalysis, ruthenium(II)-catalyzed enantioselective C-H activation has thus far largely proven elusive. In contrast, we herein report on a ruthenium(II)-catalyzed highly regio-, diastereo- and enantioselective C-H alkylation. The key to success was represented by the identification of novel C2-symmetric chiral imidazolidine carboxylic acids (CICAs), which are easily accessible in a one-pot fashion, as highly effective chiral ligands. This ruthenium/CICA system enabled the efficient installation of central and axial chirality, and featured excellent branched to linear ratios with generally >20 : 1 dr and up to 98 : 2 er. Mechanistic studies by experiment and computation were carried out to understand the catalyst mode of action.
Following the large-scale disintegration of the Larsen B Ice Shelf (LBIS) in 2002, ice flow velocities for its remnants and tributary glaciers began to increase. In this study, we used sequential Landsat images spanning 2005–2018 to produce detailed maps of the ice flow velocities and surface features for the Scar Inlet Ice Shelf (SIIS). Our results indicate that the ice flow velocities for the SIIS and its tributary glaciers (Flask and Leppard Glaciers) have substantially increased since 2005. Surface features, such as rifts and crevasses, have also substantially increased in both scope and scale and are particularly evident in the region between the Leppard Glacier and the Jason Peninsula. Several indicators—including the acceleration of ice flows, the rapid growth of major surface rifts, the heavily enhanced surface crevasses, and the dynamic position of the ice front—point to the evolving instability of the SIIS. These same indicators describe the conditions for the LBIS leading up to its 2002 collapse. To date, however, the SIIS remains intact. The formation of fast ice supporting the ice shelf front, combined with moderate mean summer temperatures, may be preventing or delaying its collapse.
Wheat leaves under different dust stress intensity were diagnosed with hyperspctrectral technology. A four-level dust stress experiment was conducted using the wheat in growing season as the study object. The spectra of wheat leaves which suffered different stress intensity levels,including severe stress, moderate stress, mild stress and no stress, were collected by ASD FieldSpec®3 spectrometer, and 32 samples were used for each level. All of the samples were divided randomly into two groups, one group with 96 ones used as calibrated set, and another with 32 ones as validated set. The spectra data were then pretreated by the methods of S.Golay smoothing and standard normal variable (SNV), and then the pretreated spectra data were analyzed with principal component analysis (PCA). Using the anterior 6 principal components computed by PCA as the model input variables, and the values of stress level as the output variables, the hyperspectral diagnosis models of dust stress intensity were established. And then the 32 unknown samples in the validated set were predicted by the diagnosis model. The result showed that the accuracy of model prediction was 87.5%, indicated it was feasible to diagnose the dust stress intensity with hyperspctral technology.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)