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排序方式: 共有774条查询结果,搜索用时 31 毫秒
1.
Separation tests using hollow-fibre modules were performed for the difficult selective extraction of trivalent actinides over fission lanthanides from acidic media. This article shows that with 2,6-di(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine as the extractant, up to 94% americium could be extracted from 1.0 kmol/m3 HNO3, with minimal lanthanide co-extraction. Using a synergistic mixture of bis(chlorophenyl)dithiophosphinic acid and tri-n-octyl phosphine oxide, tests were performed on extraction, lanthanide scrubbing and stripping. In the extraction test, up to 99.99% americium could be extracted from 0.5 kmol/m3 HNO3, with approximately one third of the lanthanides being co-extracted. Mass transfer calculations using a consistent set of input data showed good agreement with the experiments. 相似文献
2.
Experiments were conducted to determine whether changes in soil microbial populations that occur in response to additions of certain allelopathic phenolic acids to bulk soil also occur in the rhizosphere. Cucumber seedlings were transplanted into cups containing a nutrient-enriched mixture of Portsmouth B1, soil and sand and were watered five times (once every 48 hr) with aqueous solutions of ferulic,p-coumaric, or vanillic acid (each at 0, 0.25, or 0.50ol/g soil material). Nutrient solution was applied on alternate days. Leaf growth was suppressed by up to 42% by phenolic acids, but changes in root growth varied with the compound and concentration in solution. Significant increases (over 600% relative to controls) in populations of fast-growing bacteria in the rhizosphere were detected after two but not after five treatments, and increases (400% relative to controls) in numbers of fungal propagules were detected after five treatments. Such increases suggested that chronic exposure to a phenolic acid might resuit in high populations of rhizosphere microorganisms that could metabolize the compounds and thus alter observable responses by the plant. To test this, plants were watered repeatedly with a low-concentration solution of ferulic acid (chronic treatments; 0.0 or 0.1mol/g soil material in one experiment, 0.000 or 0.025imol/g soil material in a second) and then once with a highconcentration solution (acute treatment; 0.0, 0.5, or 1.0mol/g soil material in the first experiment; 0.000, 0.125, or 0.250mol/g soil material in the second).Paper No. 12385 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Research Service or the United States Department of Agriculture of the products named, nor criticism of similar ones not mentioned. Acute treatments and some chronic treatments suppressed leaf growth, but results were inconsistent for root growth. Acute treatments increased numbers of several types of bacteria in the rhizosphere but had inconsistent effects on fungi. Chronic treatments had no effect on numbers of bacteria or fungal propagules in the rhizosphere. Furthermore, chronic treatments did not alter responses of plants or microbial populations to the subsequent acute treatment. Results demonstrated that phenolic acids in soil, which must pass through the rhizosphere before interaction with plant roots can occur, alter the microbial ecology of the rhizosphere. However, microbially mediated acclimation of plants to relatively high concentrations of ferulic acid was not observed. 相似文献
3.
Udo Ziegler 《Computer Physics Communications》2004,157(3):207-216
I describe a Poisson solver for the adaptive mesh magnetohydrodynamics (MHD) code NIRVANA using ADI techniques (ADI: Alternative Direction Implicit). The solver is fit to the mesh refinement framework of the code and utilizes its special block-structured design. The key part of the method is an algorithm for the intelligent clustering of subgrids which permits the application of numerical methods based on dimensional operator splitting like ADI. Test problems show the convergence of this ansatz. 相似文献
4.
Manuel Lasch Kritika Sudan Corinna Paul Christian Schulz Thomas Kolben Julia van Dorp Sibel Eren Susanne Beyer Lorenzo Siniscalchi Sven Mahner Udo Jeschke Sarah Meister 《International journal of molecular sciences》2022,23(11)
(1) Background: Placental immune cells are playing a very important role in a successful placentation and the prevention of pregnancy complications. Macrophages dominate in number and relevance in the maternal and the fetal part of the placenta. The evidence on the polarization state of fetal and maternal macrophages involved in both, healthy and pregnancy-associated diseases, is limited. There is no representative isolation method for the direct comparison of maternal and fetal macrophages so far. (2) Material and Methods: For the isolation of decidual macrophages and Hofbauer cells from term placenta, fresh tissue was mechanically dissected and digested with trypsin and collagenase A. Afterwards cell enrichment was increased by a Percoll gradient. CD68 is represented as pan-macrophage marker, the surface markers CD80 and CD163 were further investigated. (3) Results: The established method revealed a high cell yield and purity of the isolated macrophages and enabled the comparison between decidual macrophages and Hofbauer cells. No significant difference was observed in the percentage of single CD163+ cells in the distinct macrophage populations, by using FACS and immunofluorescence staining. A slight increase of CD80+ cells could be found in the decidual macrophages. Considering the percentage of CD80+CD163− and CD80−CD163+ cells we could not find differences. Interestingly we found an increased number of double positive cells (CD80+CD163+) in the decidual macrophage population in comparison to Hofbauer cells. (4) Conclusion: In this study we demonstrate that our established isolation method enables the investigation of decidual macrophages and Hofbauer cells in the placenta. It represents a promising method for direct cell comparison, enzyme independently, and unaffected by magnetic beads, to understand the functional subsets of placental macrophages and to identify therapeutic targets of pregnancy associated diseases. 相似文献
5.
In this paper we report on a newly developed multi-gate nanowire-field-effect device (NWFET) in which the transistor type (i.e. PMOS and NMOS) is freely selectable by the application of a control-voltage. This significantly adds to flexibility in design of integrated circuits and their fabrication, respectively. We will show, that the use of midgap Schottky-barrier source and drain contacts are the key enabler for this device concept to be functional. A fully functional freely configurable CMOS-NWFET inverter circuit is presented, demonstrating the capability of this SOI technology platform. All this makes the presented NWFET-technology suitable for the fabrication multi-purpose devices for many applications. 相似文献
6.
Considering the realistic teletraffic analysis in advanced telecommunication networks, the estimation of basic characteristics of arrival processes by empirical data is an important subject of current research. Using independent observations of the interarrival times between events and the mean numbers of events in intervals of fixed length, we propose methods to estimate the intensity of a nonhomogeneous arrival stream, particularly a Poisson process, and the renewal function of a renewal process. We formulate the estimation task as stochastically ill-posed problem and apply procedures for the stabilization of the estimates. 相似文献
7.
Md Azimul Haque Appala Naidu Gandi Rajeshkumar Mohanraman Yakui Weng Bambar Davaasuren Abdul‐Hamid Emwas Craig Combe Derya Baran Alexander Rothenberger Udo Schwingenschlgl Husam N. Alshareef Shuai Dong Tom Wu 《Advanced functional materials》2019,29(13)
Organic–inorganic hybrid materials are of significant interest owing to their diverse applications ranging from photovoltaics and electronics to catalysis. Control over the organic and inorganic components offers flexibility through tuning their chemical and physical properties. Herein, it is reported that a new organic–inorganic hybrid, [Mn(C2H6OS)6]I4, with linear tetraiodide anions exhibit an ultralow thermal conductivity of 0.15 ± 0.01 W m?1 K?1 at room temperature, which is among the lowest values reported for organic–inorganic hybrid materials. Interestingly, the hybrid compound has a unique 0D structure, which extends into 3D supramolecular frameworks through nonclassical hydrogen bonding. Phonon band structure calculations reveal that low group velocities and localization of vibrational energy underlie the observed ultralow thermal conductivity, which could serve as a general principle to design novel thermal management materials. 相似文献
8.
Erkan Aydin Michele De Bastiani Xinbo Yang Muhammad Sajjad Faisal Aljamaan Yury Smirnov Mohamed Nejib Hedhili Wenzhu Liu Thomas G. Allen Lujia Xu Emmanuel Van Kerschaver Monica Morales‐Masis Udo Schwingenschlgl Stefaan De Wolf 《Advanced functional materials》2019,29(25)
Parasitic absorption in transparent electrodes is one of the main roadblocks to enabling power conversion efficiencies (PCEs) for perovskite‐based tandem solar cells beyond 30%. To reduce such losses and maximize light coupling, the broadband transparency of such electrodes should be improved, especially at the front of the device. Here, the excellent properties of Zr‐doped indium oxide (IZRO) transparent electrodes for such applications, with improved near‐infrared (NIR) response, compared to conventional tin‐doped indium oxide (ITO) electrodes, are shown. Optimized IZRO films feature a very high electron mobility (up to ≈77 cm2 V?1 s?1), enabling highly infrared transparent films with a very low sheet resistance (≈18 Ω □?1 for annealed 100 nm films). For devices, this translates in a parasitic absorption of only ≈5% for IZRO within the solar spectrum (250–2500 nm range), to be compared with ≈10% for commercial ITO. Fundamentally, it is found that the high conductivity of annealed IZRO films is directly linked to promoted crystallinity of the indium oxide (In2O3) films due to Zr‐doping. Overall, on a four‐terminal perovskite/silicon tandem device level, an absolute 3.5 mA cm?2 short‐circuit current improvement in silicon bottom cells is obtained by replacing commercial ITO electrodes with IZRO, resulting in improving the PCE from 23.3% to 26.2%. 相似文献
9.
Suman Pokhrel Cristian E. Simion Valentin S. Teodorescu Nicolae Barsan Udo Weimar 《Advanced functional materials》2009,19(11):1767-1774
Widely applicable nonaqueous solution routes have been employed for the syntheses of crystalline nanostructured tungsten oxide particles from a tungsten hexachloride precursor. Here, a systematic study on the crystallization and assembly behavior of tungsten oxide products made by using the bioligand deferoxamine mesylate (DFOM) (product I ), the two chelating ligands hexadecyltrimethylammoniumbromide (CTAB) ( II ) and poly(alkylene oxide) block copolymer (Pluronic P123) ( III ) is presented. The mechanistic pathways for the material synthesis are also discussed in detail. The tungsten oxide nanomaterials and reaction solutions are characterized by Fourier transform IR, 1H, and 13C NMR spectroscopies, powder X‐ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high‐resolution TEM, and selected‐area electron diffraction. The indexing of the line pattern suggests WO3 is in its monoclinic structure with a = 0.7297 nm, b = 0.7539 nm, c = 0.7688 nm, and β‐i; = 90.91 °. The nanoparticles formed have various architectures, such as chromosomal shapes (product I ) and slates ( II ), which are quite different from the mesoporous one ( III ) that has internal pores or mesopores ranging from 5 to 15 nm. The nanoparticles obtained from all the synthetic procedures are in the range of 40–60 nm. The investigation of the gas‐sensing properties of these materials indicate that all the sensors have good baseline stability and the sensors fabricated from material III present very different response kinetics and different CO detection properties. The possibility of adjusting the morphology and by that tuning the gas‐sensing properties makes the preparation strategies used interesting candidates for fabricating gas‐sensing materials. 相似文献
10.
Jürgen K. P. Weder Udo Scharf 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1981,172(3):185-189
Summary Fingerprinting (thin-layer electrophoresis/chromatography) after tryptic or chymotryptic digestion of performic acid-oxidized monomeric, dimeric, and oligomeric ribonuclease isolated from heated ribonuclease and monomeric unheated ribonuclease demonstrates one additional peptide in all heated samples. Preparative ion-exchange chromatography of the tryptic digests results in the corresponding number of fractions, 15 and 14, respectively. Amino acid analysis andN-terminal amino acid determination relate most of these peptides to theoretical tryptic peptides, whilst some are formed by further fragmentation due to chymotryptic activity of the commercial TPCK-trypsin used. This is also true of the additional peptide found in heated samples. So no distinct crosslinking peptide could be demonstrated. Only favoured participation of theN-terminal region in crosslinking is indicated. The observed differences between heated and unheated samples must be due to differences in three-dimensional structure leading to differences in susceptibility for proteolytic enzymes. Demonstration of both isopeptides, aspartyllysine and glutamyllysine, in three out of five fractions from digests of ribonuclease dimer, indicating six different isopeptide crosslinks, confirms the assumption of a very unspecific formation of crosslinks during protein heating.
We thank the Deutsche Forschungsgemeinschaft for supporting this work and Mrs. Anneliese Mödl and Mrs. Angelika Langwieser for performing the amino acid analyses 相似文献
Modelluntersuchungen über das Erhitzen von Lebensmittelproteinen —Oligomerisierung von Ribonuclease beim ErhitzenIII. Über die Lokalisierung säurelabiler Brückenpeptide
Zusammenfassung Durch zweidimensionale Dünnschichtelektrophorese/-chromatographie nach tryptischer oder chymotryptischer Spaltung perameisensäureoxidierter monomerer, dimerer und oligomerer Ribonuclease aus erhitzter Ribonuclease sowie monomerer unerhitzter Ribonuclease wurde ein zusätzliches Peptid in allen erhitzten Proben nachgewiesen. Durch präparative Ionenaustauscherchromatographie tryptischer Hydrolysate wurden dementsprechend 15 bzw. 14 Fraktionen erhalten. Durch Aminosäureanalyse und Bestimmung derN-terminalen Aminosäuren konnten die meisten Peptide theoretischen tryptischen Spaltpeptiden zugeordnet werden, während einige durch weitergehende Spaltung aufgrund chymotryptischer Nebenaktivitäten im verwendeten TPCK-Trypsinpräparat gebildet werden. Dies gilt auch für das in erhitzten Proben zusätzlich gefundene Peptid, so daß kein spezifisches Brückenpeptid nachgewiesen werden konnte. Lediglich eine bevorzugte Beteiligung desN-terminalen Bereiches an Quervernetzungsreaktionen ist erkennbar. Die beobachteten Unterschiede zwischen erhitzten und unerhitzten Proben beruhen auf unterschiedlicher räumlicher Anordnung, die zu Unterschieden in der Zugänglichkeit für proteolytische Enzyme führt. In drei von fünf untersuchten Fraktionen tryptisch gespaltener dimerer Ribonuclease konnten jeweils beide Isopeptide, Aspartyl-lysin und Glutamyl-lysin, also insgesamt sechs verschiedene Isopeptidbrücken nachgewiesen werden. Damit wird die Annahme einer sehr unspezifischen Brückenbildung während der Proteinerhitzung bestätigt.
We thank the Deutsche Forschungsgemeinschaft for supporting this work and Mrs. Anneliese Mödl and Mrs. Angelika Langwieser for performing the amino acid analyses 相似文献