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排序方式: 共有594条查询结果,搜索用时 15 毫秒
71.
W R Chang R Gr?nqvist S Leclercq R Myung L Makkonen L Strandberg R J Brungraber U Mattke S C Thorpe 《Ergonomics》2001,44(13):1217-1232
Friction has been widely used as a measure of slipperiness. However, controversies around friction measurements remain. The purposes of this paper are to summarize understanding about friction measurement related to slipperiness assessment of shoe and floor interface and to define test conditions based on biomechanical observations. In addition, friction mechanisms at shoe and floor interface on dry, liquid and solid contaminated, and on icy surfaces are discussed. It is concluded that static friction measurement, by the traditional use of a drag-type device, is only suitable for dry and clean surfaces, and dynamic and transition friction methods are needed to properly estimate the potential risk on contaminated surfaces. Furthermore, at least some of the conditions at the shoe/floor interface during actual slip accidents should be replicated as test conditions for friction measurements, such as sliding speed, contact pressure and normal force build-up rate. 相似文献
72.
Bernadette Peace Michael Topka Kenneth Skorenko Adam Kowalski Ursula Williams Michael Hagerman Rebecca Cortez 《Materials Letters》2011,65(21-22):3208-3211
We report on morphosynthesis techniques that have been employed to tune polyamine film nanoarchitectures and on their resulting morphologies. Specific layers discussed include films of aniline/Laponite clay and aniline solution processed with V2O5 catalyst. Synthesis approaches examined include films generated in-situ (glass templating), solution based drop casting, and mechanochemical grinding. Surface topography results suggest that these approaches provide dimensionality control of the polyaniline morphology. Surface images of the mechanochemically ground polyaniline/Laponite nanocomposite layer reveal interfacial contact which is promising for potential heterojunction solar cell designs. 相似文献
73.
M. Pischetsrieder Ursula Gro? Christiane Schoetter 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1999,209(1):172-177
Two HPLC methods with diode array detection were used to separate Maillard products from milk components. The Maillard products
4-(β-d-galactopyranosyloxy)-2-hydroxy-2-methyl-2H-pyran-3(6H)-one (2), 1-[3-(β-d-galactopyranosyloxy)-2-furanyl]-1-ethanone (4), 4-(β-d-galactopyranosyloxy)-5-(hydroxymethyl)-2-methyl-3(2H)-furanone (5), isomaltol (7), maltol (9), 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (6), and 5-hydroxymethyl-2-furfuraldehyde (8) were determined using a water-methanol gradient. Furthermore, 4,5-dihydroxy-2-(β-d-galactopyranosyloxy)-5-methyl-2-cyclopenten-1-one (3) was separated from the milk components by applying the interaction reagent octylamine. Several heated or processed milk
samples were analyzed, and formation of the Maillard products was determined and quantified. Thus it was found that 2 and 3 are early products of the Maillard reaction in milk, whereas after prolonged heating 4, 5, and particularly 9 and 6 become more important. Compounds 7 and 8 were not detected, even if the samples were heated under stringent conditions. 相似文献
74.
Olaf A.M. Fisscher Klaasjan Visscher Alan Pearson Ursula Weisenfeld 《Creativity & Innovation Management》2001,10(4):251-258
Research and development departments in industrial firms may not take it for granted anymore that they are the only preferred supplier of research and development to the company of which they are a part. The growing need to be innovative and the increasing availability of innovative competencies on the market result in a pressure on these departments to become more business–like and to reconsider their sources of competitive advantage over other (potential) suppliers of research and development. Traditionally, scientific and technological knowledge and skills concerning the product were the prime source. Nowadays, managerial competencies and the ability to work for and with your clients and suppliers are becoming more important. To become a competitive business in a business, research and development departments should create the competencies that enable them to create value for their clients. This calls for good competence management, comprising management of human resources, information technology, and internal and external interfaces. In this paper we explore what it means and what it takes for research and development departments to implement competence management, elaborating it theoretically and describing a case of competence management in the research and development department of a European car company. 相似文献
75.
Ursula Wölwer-Rieck und Hans Büning-Pfaue 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1990,191(4-5):319-321
Zusammenfassung Es wird eine HPLC-Methode vorgestellt, die es gestattet, Furazolidon (FZ) neben seinem offenkettigen Cyanometaboliten 3-(4-Cyano-2-oxobutyli-denamino)-2-oxazolidon (M1) in Forellen nachzuweisen. Im Muskel und Leber von Forellen, die 7 Tage lang mit FZ-haltigem Futter behandelt worden waren, konnten nur während der Behandlungszeit Rückstände von M1 und FZ nachgewiesen werden. Schon zu Beginn der Absetzzeit lagen die Konzentrationen an FZ und M1 unterhalb der Nachweisgrenze.
The residue behaviour of the furazolidone metabolite 3-(4-Cyano-2-oxobutylideneamino)-2-oxazolidone in trout
Summary A high-performance liquid chromatography (HPLC)-method for the determination of furazolidone (FZ) and its open-chain cyano-derivative 3-(4-cyano-2-oxobutylideneamino)-2-oxazolidone (M1) in trout is described. Only during the medication period residues of FZ and M1 were detected in the muscle and liver of the trout, which were treated with food containing FZ over a period of 7 days. After the beginning of the withdrawal period, the concentration of FZ and M1 were found to be under the limits of detection.相似文献
76.
Celeste Fernández Eduardo Lujano Ursula Macias Josseilin Marcano Pablo J. Baricelli Clementina Longo Sergio A. Moya María G. Solórzano Marisol C. Ortega Alvaro J. Pardey 《Catalysis Letters》2004,95(3-4):143-150
Rhodium(I) complexes of the type, cis-[Rh(CO)2(amine)2](PF6) where (amine = 3-picoline, 2-picoline, pyridine, 2,6-lutidina or 3,5-lutidine) dissolved in 80% aqueous amine solutions catalyzed the selective reduction of 4-nitrobenzoic acid to 4-aminobenzoic acid under CO atmosphere. The importance of these catalytic systems is their high chemo selectivity for the aromatic nitro group of the 4-nitrobenzoic acid with respect to the carboxylic group, allowing the production of the desired aromatic amine in high yields. The 4-aminobenzoic acid production depends on the nature of the coordinated amine. The Rh/3,5-lutidine system, the most active catalyst among tested, displays turnover frequencies for 4-aminobenzoic acid production of about 173 moles per mole Rh per day for [Rh] = 1 × 10?4 mol, [4-nitrobenzoic acid] = 3.82 × 10?3mol, 10 mL of 80% aqueous 3,5-lutidine, P(CO) = 0.9 atm at 100 °C. Analyses of kinetic results for the Rh/3,5-lutidine system show a first order dependence on 4-nitrobenzoic acid concentration, a non-linear dependence on CO pressure, a segmented Arrhenius plot and dependence on the nature of the reducing gas agent. These data are discussed in terms of a possible mechanism. 相似文献
77.
78.
Baltes Paul B.; Staudinger Ursula M.; Maercker Andreas; Smith Jacqui 《Canadian Metallurgical Quarterly》1995,10(2):155
This study examined whether our conception of wisdom has a psychological bias, by focusing on a group of distinguished individuals nominated as being wise. The comparison groups included older clinical psychologists and highly educated old and young control groups. Wisdom-related knowledge was assessed by 2 tasks and evaluated with a set of 5 wisdom criteria. First, old wisdom nominees performed as well as clinical psychologists who in past research had shown the highest levels of performance. Second, wisdom nominees excelled in the task of existential life management and the criterion of value relativism. Third, up to age 80, older adults performed as well as younger adults. If there is a psychological bias to our conception of wisdom, this does not prevent nonpsychologists from being among the top performers. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
79.
Iqbal U Albaghdadi H Nieh MP Tuor UI Mester Z Stanimirovic D Katsaras J Abulrob A 《Nanotechnology》2011,22(19):195102
Molecular imaging enables the non-invasive investigation of cellular and molecular processes. Although there are challenges to overcome, the development of targeted contrast agents to increase the sensitivity of molecular imaging techniques is essential for their clinical translation. In this study, spontaneously forming, small unilamellar vesicles (sULVs) (30 nm diameter) were used as a platform to build a bimodal (i.e., optical and magnetic resonance imaging (MRI)) targeted contrast agent for the molecular imaging of brain tumors. sULVs were loaded with a gadolinium (Gd) chelated lipid (Gd-DPTA-BOA), functionalized with targeting antibodies (anti-EGFR monoclonal and anti-IGFBP7 single domain), and incorporated a near infrared dye (Cy5.5). The resultant sULVs were characterized in vitro using small angle neutron scattering (SANS), phantom MRI and dynamic light scattering (DLS). Antibody targeted and nontargeted Gd loaded sULVs labeled with Cy5.5 were assessed in vivo in a brain tumor model in mice using time domain optical imaging and MRI. The results demonstrated that a spontaneously forming, nanosized ULVs loaded with a high payload of Gd can selectively target and image, using MR and optical imaging, brain tumor vessels when functionalized with anti-IGFBP7 single domain antibodies. The unique features of these targeted sULVs make them promising molecular MRI contrast agents. 相似文献
80.
Katharina Kerschan-Schindl Maria Papageorgiou Ursula Fger-Samwald Maria Butylina Michael Weber Peter Pietschmann 《International journal of molecular sciences》2022,23(23)
It remains uncertain which skeletal sites and parameters should be analyzed in rodent studies evaluating bone health and disease. In this cross-sectional mouse study using micro-computed tomography (µCT), we explored: (1) which microstructural parameters can be used to discriminate female from male bones and (2) whether it is meaningful to evaluate more than one bone site. Microstructural parameters of the trabecular and/or cortical compartments of the femur, tibia, thoracic and lumbar vertebral bodies, and skull were evaluated by µCT in 10 female and 10 male six-month-old C57BL/6J mice. The trabecular number (TbN) was significantly higher, while the trabecular separation (TbSp) was significantly lower in male compared to female mice at all skeletal sites assessed. Overall, bone volume/tissue volume (BV/TV) was also significantly higher in male vs. female mice (except for the thoracic spine, which did not differ by sex). Most parameters of the cortical bone microstructure did not differ between male and female mice. BV/TV, TbN, and TbSp at the femur, and TbN and TbSp at the tibia and lumbar spine could fully (100%) discriminate female from male bones. Cortical thickness (CtTh) at the femur was the best parameter to detect sex differences in the cortical compartment (AUC = 0.914). In 6-month-old C57BL/6J mice, BV/TV, TbN, and TbSp can be used to distinguish male from female bones. Whenever it is not possible to assess multiple bone sites, we propose to evaluate the bone microstructure of the femur for detecting potential sex differences. 相似文献