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排序方式: 共有1671条查询结果,搜索用时 437 毫秒
111.
Joann Huber Robert G.K. Donald Sang Ho Lee Lisa Wang Jarantow Michael J. Salvatore Xin Meng Ronald Painter Russell H. Onishi James Occi Karen Dorso Katherine Young Young Whan Park Stephen Skwish Michael J. Szymonifka Tim S. Waddell Lynn Miesel John W. Phillips Terry Roemer 《Chemistry & biology》2009,16(8):837-848
112.
Tim Römer 《Journal of Algebra》2008,319(1):1-15
We study the relationship between the Tor-regularity and the local-regularity over a positively graded algebra defined over a field which coincide if the algebra is a standard graded polynomial ring. In this case both are characterizations of the so-called Castelnuovo–Mumford regularity. Moreover, we can characterize a standard graded polynomial ring as a K-algebra with extremal properties with respect to the Tor- and the local-regularity. For modules of finite projective dimension we get a nice formula relating the two regularity notions. Interesting examples are given to help to understand the relationship between the Tor- and the local-regularity in general. 相似文献
113.
We use Janelidze's Categorical Galois Theory to extend Brown and Ellis's higher Hopf formulae for homology of groups to arbitrary semi-abelian monadic categories. Given such a category A and a chosen Birkhoff subcategory B of A, thus we describe the Barr-Beck derived functors of the reflector of A onto B in terms of centralization of higher extensions. In case A is the category Gp of all groups and B is the category Ab of all abelian groups, this yields a new proof for Brown and Ellis's formulae. We also give explicit formulae in the cases of groups vs. k-nilpotent groups, groups vs. k-solvable groups and precrossed modules vs. crossed modules. 相似文献
114.
A series of 5-trichloro-Δ4-1,2,4-oxadiazolines have been synthesised by 1,3-dipolar cycloaddition of nitrones to trichloroacetonitrile. These oxadiazolines rearrange into formamidine derivatives, via ring opening and a 1,2-aryl shift from carbon to the adjacent amino nitrogen. Both cycloaddition and rearrangement are facilitated when electron deficient nitriles and electron rich nitrones are used. 相似文献
115.
116.
Clarissa Müller Tim Ortmann Akram Abi Dave Hartig Stephan Scholl Hans-Joachim Jördening 《Applied biochemistry and biotechnology》2017,182(1):197-215
Immobilization methods and carriers were screened for immobilization of Euglena gracilis extract with laminaribiose phosphorylase activity. The extract was successfully immobilized on three different carriers via covalent linkage. Suitable immobilization carriers were Sepabeads EC-EP/S and ECR 8209M with epoxy groups and ECR 8309M with amino groups as functional units. Immobilization on Sepabeads EC-EP/S resulted in highest retained activity (65%). The immobilizates were characterized for pH, temperature, and buffer molarity preferences. The immobilized enzyme lost 48% of its activity when used seven times. Together with sucrose phosphorylase, laminaribiose phosphorylase was successfully applied for bienzymatic production of laminaribiose from sucrose and glucose with a final laminaribiose concentration of 14.3 ± 2.1 g/L (20% yield). 相似文献
117.
Tavorite‐structured oxyphosphates, fluorophosphates, oxysulfates, and fluorosulfates are evaluated for use as cathode materials in lithium ion batteries and activation energies for lithium diffusion through LiVO(PO4), LiV(PO4)F, and LiFe(SO4)F are calculated. 相似文献
118.
Hans J. Breunig Tim Koehne Ana Maria Preda Cristian Silvestru Luis F. Piedra-Garza 《Journal of organometallic chemistry》2010,695(9):1307-1313
The syntheses and spectroscopic (NMR, MS) investigations of the antimonates [Ph4P]+[Me2SbCl4]− (1), [Me4Sb]+[Me2SbCl4]− (2), [Et4N]+[Ph2SbCl4]− (3), [Bu4N]+[Ph2SbCl4]− (4), [Me4Sb]+[Ph2SbCl4]− (5), [Et3MeSb]+[Ph2SbCl4]− (6), [Et4N]+[Ph2SbF4]− (7) and [Et4N]+[Ph2SbBr4]− (8) are reported. Halogen scrambling reactions of Et4NBr or Ph4EBr (E = P, Sb) with R2SbCl3 (R = Me, Ph) produce mixtures of compounds from which crystals of [Et4N]+[Ph2SbBr1.24Cl2.76]− (9), [Et4N]+[Ph2SbBr2.92Cl1.08]− (10) or [Ph4Sb]+[Me2SbCl4]− (11) were isolated. The crystal and molecular structures of 1 and 3-11 are reported. 相似文献
119.
Vladimir Strezov Artur Ziolkowski Tim J. Evans Peter F. Nelson 《Journal of Thermal Analysis and Calorimetry》2010,100(3):901-907
Ironmaking involves reduction of iron ores to metallic iron using coke, coal or gas as reductants. Although different iron ore reduction processes exist, prior to each reduction type, commonly, the hydroxyl and clay materials present in the iron ores undergo decomposition as a first stage. The mass loss during decomposition of these materials is termed as Loss on Ignition (LOI). The aim of this work is to apply a computer aided thermoanalytical technique to evaluate five different iron ore types during decomposition of the LOI matter and determine associated decomposition temperature ranges and heats of reactions. Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis (TG) were also incorporated to support the analysis interpretation. Three distinctive temperature ranges of decomposition of iron ore LOI matter were detected. The first region was associated with dehydration of the hygroscopic moisture at a temperature range between 100 and 150 °C. The second region occurred at a temperature range between 260 and 425 °C during which strongly bonded water was released and the OH groups associated with primarily iron oxyhydroxides were fractured. The third range, which occurred at a temperature range of 530 and 605 °C, was related to decomposition of the aluminosilicate clay materials. 相似文献
120.
Tim Desmet T. Billiet Elke Berneel Ria Cornelissen David Schaubroeck Etienne Schacht Peter Dubruel 《Macromolecular bioscience》2010,10(12):1484-1494
In the last decade, substantial research in the field of post‐plasma grafting surface modification has focussed on the introduction of carboxylic acids on surfaces by grafting acrylic acid (AAc). In the present work, we report on an alternative approach for biomaterial surface functionalisation. Thin poly‐ε‐caprolactone (PCL) films were subjected to a dielectric barrier discharge Ar‐plasma followed by the grafting of 2‐aminoethyl methacrylate (AEMA) under UV‐irradiation. X‐ray photoelectron spectroscopy (XPS) confirmed the presence of nitrogen. The ninhydrin assay demonstrated, both quantitatively and qualitatively, the presence of free amines on the surface. Confocal fluorescence microscopy (CFM), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to visualise the grafted surfaces, indicating the presence of pAEMA. Static contact angle (SCA) measurements indicated a permanent increase in hydrophilicity. Furthermore, the AEMA grafted surfaces were applied for comparing the physisorption and covalent immobilisation of gelatin. CFM demonstrated that only the covalent immobilisation lead to a complete coverage of the surface. Those gelatin‐coated surfaces obtained were further coated using fibronectin. Osteosarcoma cells demonstrated better cell‐adhesion and cell‐viability on the modified surfaces, compared to the pure PCL films.