检索结果-南通市图书馆

Iron catalyzed Michael addition: Chloroferrate ionic liquids as efficient catalysts under microwave conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2012年第8期55卷 1614-1619页

作者： VASILOIU Maria GAERTNER Peter bICA katharina Institute of Applied Synthetic Chemistry Vienna University of Technology Vienna A-1060 Austria

The iron containing ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate （[C4mim]C1/FeCl3; Z = 0.5） proved to be an efficient catalyst for the solvent-free metal catalyzed Michael addition of β-keto esters and enones. Due to the ionic structure of the catalyst, a significant acceleration of the reaction rate was observed under microwave conditions. Furthermore, recycling of the ionic liquid catalyst could be performed after simply distilling off the products.

关键词： ionic liquids iron catalysis michael addition lewis acid microwave chemistry

维普期刊数据库

Divergent foraging behavior in a hybrid zone： Darwin＇s tree finches （Camarhynchus spp.） on Floreana Island

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2015年第1期61卷 181-190页

作者： katharina J. PETERS Sonia KLEINDORFER School of biological Sciences Flinders University GPO Box 2100 Adelaide 5001 Australia

Hybrid speciation is increasingly recognized as a mechanism for novel evolutionary trajectories. However, we know very little about the ecology of a contact zone that has arisen in sympatry. This study examines the foraging behavior and fitness of two species of Darwin＇s tree finches （Camarhynchus parvulus, C pauper） and hybrid offspring on Floreana Island. Previous study showed that the percentage of hybrids in the tree finch population increased from 19% in 2005 to 41% in 2010, and their body and beak size increased by -5% （parental phenotype did not change）. In 2005-2006, all three tree finch groups （two paren- tal species and hybrid birds） used the same foraging substrate, technique, and height. by 2010-2013, the small tree finch C. par- vulus had changed its foraging technique and the medium tree finch C. pauper had changed its foraging height. both parental species had higher body condition when foraging at （divergent） mean foraging heights per species but hybrid birds did not. We discuss the implications of conserving forest to facilitate vertical niche expansion and the role of hybridization for genetic persis- tence [Current Zoology 61 （1）： 181-190, 2015].

关键词： Hybridization Speciation Adaptive radiation Conservation Scalesia Ecological niche

Discrete Vector Calculus and Helmholtz Hodge Decomposition for Classical Finite Difference Summation by Parts Operators

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2020年第4期2卷 581-611页

作者： Hendrik Ranocha katharina Ostaszewski Philip Heinisch Institute Computational Mathematics TU BraunschweigUniversitatsplatz 238106 BrunswickGermany Extreme Computing Research Center(ECRC) Computer Electrical and Mathematical Science and Engineering Division(CEMSE)King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia Institut für Angewandte Numerische Wissenschaft e.V.(IANW) Bienroder Straae 338110 BrunswickGermany Institut für Geophysik und Extraterrestrische Physik TU BraunschweigMendelssohnstraBe 338106 BrunswickGermany

In this article,discrete variants of several results from vector calculus are studied for clas-sical finite difference summation by parts operators in two and three space *** is shown that existence theorems for scalar/vector potentials of irrotational/solenoidal vector fields cannot hold discretely because of grid oscillations,which are characterised *** results in a non-vanishing remainder associated with grid oscillations in the discrete Helmholtz Hodge ***,iterative numerical methods based on an interpretation of the Helmholtz Hodge decomposition via orthogonal projections are pro-posed and applied *** numerical experiments,the discrete remainder vanishes and the potentials converge with the same order of accuracy as usual in other first-order partial differential *** by the successful application of the Helmholtz Hodge decomposition in theoretical plasma physics,applications to the discrete analysis of magnetohydrodynamic(MHD) wave modes are presented and discussed.

关键词： Summation by parts Vector calculus Helmholtz Hodge decomposition Mimetic properties Wave mode analysis

Effect of faade systems on the performance of cooling ceilings: In situ measurements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2015年第1期4卷 68-78页

作者： katharina Eder Thomas bednar Department for building Physics and building Acoustic Vienna University of TechnologyAdolf-Blamauer-Gasse 1-31030ViennaAustria

This article presents an innovative faade system designed to increase the thermal comfort inside an office room and to enhance the cooling capacity of the suspended cooling ceiling.A series of measurements is conducted in an existing office building with different faade systems(i.e., a combination of glazing and shading). An innovative faade system is developed based on this intensive set of measurements. The new system enhances the thermal comfort and cooling capacity of the suspended cooling ceiling. The main usage of the new system is the refurbishment and improvement of existing faade systems.

关键词： Office building Innovative fa?ade systems Cooled ceiling Increase in the cooling capacity of cooled ceiling Interaction of building envelope and cooled ceiling Effect on comfort

Analysis of Fusarium Toxins in Single barley Malt Kernels

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Analysis and Testing 2018年第2期2卷 124-137页

作者： katharina Habler Sarah Moghari Michael Rychlik Analytical Food Chemistry Technical University of MunichMaximus‑von‑Imhof‑Forum 285354 FreisingGermany

Fusarium infestation of barley and other cereals can result in red mycelium and is often accompanied by mycotoxin *** assessment and rejection of malt batches that contain more than 5–7 relevant red kernels are so far common tools in the malting and brewing industry to guarantee high-quality malt and *** single barley malt kernels were collected from naturally contaminated barley cultivars(Grace,Quench,and Malwinta)as well as from barley varieties(Grace,Quench,and Scarlett)inoculated with three different Fusarium species(Fusarium culmorum,Fusarium graminearum,and Fusarium avenaceum).A recently published multi-mycotoxin LC–MS/MS method was altered slightly and used for the analysis of Fusarium toxins of each *** comparison of the contamination level with the degree of discoloration revealed only limited *** seems that the visual assessment of the red mycelium of single kernels is particularly sensitive towards the occurrence of enniatins and might neglect that of other mycotoxins.

关键词： Fusarium Mycotoxins barley Malt Red kernel Single grain analysis

2. The origin and pathogenesis of epithelial ovarian cancer: a proposed unifying theory.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国肿瘤临床 2010年第12期37卷 725-726页

作者： katharina Spanel-borowski Universjty of Leipzig Germany

Kurman RJ, Shih IeM Am J Surg Pathol 2010 Mar 34(3):433-43 Comments This paradigm-changing review proposes anew theory for the pathogenesis of ovariancancer; it proposes that ovarian cancerarises from precursor lesions from outsidethe ovary. The review is comprehensiveand adequately based on past and presentknowledge of ovarian cancer and a goodexample that there is constant progress inbasic and clinical science.

关键词： gene a proposed unifying theory The origin and pathogenesis of epithelial ovarian cancer

Does ash dieback affect the reproductive ecology of Fraxinus excelsior L.?

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Forestry Research 2024年第2期35卷 54-69页

作者： Anna‑katharina Eisen Lisa buchner barbara Fussi Susanne Jochner‑Oette Physical Geography/Landscape Ecology and Sustainable Ecosystem Development Catholic University of Eichstätt-Ingolstadt85072 EichstättGermany bavarian Office for Forest Genetics(AWG) 83317 TeisendorfGermany

Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest *** ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior *** have a major impact on the quantity and quality of pollen and *** this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to *** were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern *** all parameters were examined at every site every *** average pollen production per tree was estimated at 471.2±647.9 billion pollen *** addition,we found that a high number of inflorescences did not equate to high pollen production per *** production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced *** regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable ***,a significant difference could only be calculated for trees in the floodplain *** percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed *** percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in ***-viable seeds were usually heavily infested by *** general,seed quality was not significantly different between healthy and diseased *** results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed ***,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive per

关键词： Common ash Seed orchard Floodplain forest Pollen production Viability TTC test Seed stratification Phenology

维普期刊数据库

Reduced-form setting under model uncertainty with non-linear affine intensities

在线全文

学校读者我要写书评

暂无评论

Probability, Uncertainty and Quantitative Risk 2021年第3期6卷 159-188页

作者： Francesca biagini katharina Oberpriller Department of Mathematics Workgroup Financial and Insurance MathematicsUniversity of Munich(LMU)Theresienstraße 3980333 MunichGermany Department of Mathematics of Natural Social and Life SciencesGran Sasso Science Institute(GSSI)Viale F.Crispi 767100 L’AquilaItaly

In this paper we extend the reduced-form setting under model uncertainty introduced in[5]to include intensities following an affine process under parameter uncertainty,as defined in[15].This framework allows us to introduce a longevity bond under model uncertainty in a way consistent with the classical case under one prior and to compute its valuation ***,we price a contingent claim with the sublinear conditional operator such that the extended market is still arbitrage-free in the sense of“no arbitrage of the first kind”as in[6].

关键词： Sublinear expectation Reduced-form framework Non-linear affine processes Arbitrage-free pricing

Stability and deactivation of OER electrocatalysts: A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第6期31卷 301-329,I0009页

作者： Feng Zeng Chalachew Mebrahtu Longfei Liao Anna katharina beine Regina Palkovits State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816JiangsuChina Institute of Technical and Macromolecular Chemistry RWTH Aachen UniversityWorringerweg 252074 AachenGermany Max Planck Institute for Chemical Energy Conversion Stiftstraße.34–3645470 Mülheim an der RuhrGermany

Recently, H_(2) has attracted increasing attention as green energy carrier holding the possibility to replace fossil fuel-based energy sources and thereby reduce CO_(2) emissions. Green hydrogen can be generated by water electrolysis using renewable energies like wind and solar power. When it is combusted, only water forms as by-product. However, the efficiency of water electrolysis is hampered by the anodic oxygen evolution reaction(OER) because of the slow kinetics which leads to a high overpotential. Therefore, many catalysts have been developed for OER to facilitate the kinetics and reduce the overpotential. In addition to electrocatalytic activity, the stability of the catalysts is imperative for industrial application and has been intensively studied. In this review, we cover recent findings on the stability and deactivation mechanisms of OER catalysts. We discuss the correlation between OER activity and stability, methodologies and experimental techniques to study the stability and deactivation as well as the deactivation mechanisms, together with factors influencing stability. Furthermore, strategies for stabilizing and regenerating OER catalysts as well as methods to predict stability are summarized. Finally, the review highlights emerging methodologies yet to be explored and future directions of stability studies and the design of highly stable OER catalysts.

关键词： Oxygen evolution OER Stability Durability Deactivation

维普期刊数据库