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排序方式: 共有585条查询结果,搜索用时 15 毫秒
91.
LK DeNicola JL Falk ME Swanson MO Gayle N Kissoon 《Canadian Metallurgical Quarterly》1997,13(3):477-502
Drowning and near drowning remain a common cause of childhood death and disability. Toddlers aged one through four drown in private swimming pools. Submersions greater than 10 minutes and lack of CPR at the scene or the need for greater than 20 minutes of resuscitation portends a poor prognosis. Management of respiratory failure without neurologic impairment has the most successful outcome. Prevention of drowning morbidity is dependent on constant parental supervision, and immediate and expert CPR. 相似文献
92.
Wolfgang Gindl-Altmutter Jozef Keckes Johannes Plackner Falk Liebner Karl Englund Marie-Pierre Laborie 《Composites Science and Technology》2012
All-cellulose composites (ACCs) were prepared by partial dissolution in ionic liquid and compared to composites with epoxy matrix. Wide-angle X-ray diffraction and scanning electron microscopy were used to reveal differences in the structure of the composites. In tensile tests, lyocell-fibre based ACCs showed similar strength and stiffness, yet superior extensibility compared to lyocell-epoxy composites. However, when flax fibres were used, tensile properties clearly inferior to flax-epoxy were observed. Dynamic-mechanical and thermogravimetric analysis revealed a favourable behaviour for ACC in terms of more diffuse thermal softening and increased resistance to thermal degradation. 相似文献
93.
Masoumeh Ghorbani Arunjunai Raj Mahendran Hendrikus W. G. van Herwijnen Falk Liebner Johannes Konnerth 《Holz als Roh- und Werkstoff》2018,76(2):481-487
Suitability of lignin–phenol–formaldehyde (LPF) resoles was investigated for manufacturing paper-based high-pressure laminates. As lignin source, pine kraft lignin and spruce sodium lignosulfonate were compared, substituting 40 wt% of phenol by lignin in each case. The synthesized resins were characterized for their viscosity development, solid content, pH, free formaldehyde as well as free phenol content and B-time. Paper-based high-pressure laminates were manufactured using the two different resins. The laminates were exposed to different test climates and were compared for boiling water resistance, thickness swelling, bending properties and impact energy. The results indicate that pine kraft lignin performs superior to spruce sodium lignosulfonate for utilization in paper based laminates for outdoor usage due to a lower affinity of the pine kraft LPF laminates to water. 相似文献
94.
95.
The transverse hygro-expansion of Norway spruce wood is studied on the growth ring level using digital image correlation. This non-destructive technique offers the possibility for a contactless study of deformation fields of relatively large areas. The measured full-field strains are segmented into individual growth rings. Whereas radial strains closely follow the density progression with the maximum in the dense latewood (LW), tangential and shear strain remain constant except for positions around the edges of the sample. A simple FE three phase growth ring model is in good agreement with the experimental values. The selective activation of individual phases like earlywood (EW), transition wood and LW demonstrates that the radial hygro-expansion is dominated by the EW deformation, whereas tangential deformation is a complex interplay of expansion and compression that needs all tissues to fully develop. 相似文献
96.
Dr. Rhushikesh A. Kulkarni Dr. Nadeem A. Vellore Matthew R. Bliss Dr. Stephanie M. Stanford Matthew D. Falk Prof. Nunzio Bottini Prof. Riccardo Baron Prof. Amy M. Barrios 《Chembiochem : a European journal of chemical biology》2013,14(13):1640-1647
Assay design is an important variable that influences the outcome of an inhibitor screen. Here, we have investigated the hypothesis that protein tyrosine phosphatase inhibitors with improved biological activity could be identified from a screen by using a biologically relevant peptide substrate, rather than traditional phosphotyrosine mimetic substrates. A 2000‐member library of drugs and drug‐like compounds was screened for inhibitors of lymphoid tyrosine phosphatase (LYP) by using both a peptide substrate (Ac‐ARLIEDNE‐pCAP‐TAREG‐NH2, peptide 1) and a small‐molecule phosphotyrosine mimetic substrate (difluoromethyl umbelliferyl phosphate, DiFMUP). The results demonstrate that compounds that inhibited enzyme activity on the peptide substrate had greater biological activity than compounds that only inhibited enzyme activity on DiFMUP. Finally, epigallocatechin‐3,5‐digallate was identified as the most potent inhibitor of lymphoid tyrosine phosphatase activity to date, with an IC50 of 50 nM and significant activity in T‐cells. Molecular docking simulations provided a first model for binding of this potent inhibitor to LYP; this will constitute the platform for ongoing lead optimization efforts. 相似文献
97.
In this paper, we investigate the possibility to suppress interference in wideband multiple-input multiple-output radar. The idea is to employ tunable filters at the transmitter and the receiver sides, and to derive filter coefficients that result in optimal transmitted signals from a system performance point of view, for a given radar scenario. The system performance is measured in signal-to-interference-and-noise ratio (SINR) at the receiver output, from which the filter properties are derived. The focus is to suppress active jamming interference, and especially deceptive jamming interference. We discuss two ways to derive the transmit and the receive filters. Each procedure utilizes two different power constraints related to the transmit filters. To incorporate imperfections in the given scenario, a robust extension to the design problem is proposed. Two different robust methods are evaluated: one that utilizes a Taylor series expansion of the SINR, and one that exploits a worst-case SINR maximization. Numerical validation illustrates the possibility to suppress interference without actually forming a spatial null in the direction towards interference, and the necessity to design transmit filters that are robust to uncertainties in the given scenario. 相似文献
98.
99.
Falk Heinroth Simon Münzer Armin Feldhoff Sven Passinger Wei Cheng Carsten Reinhardt Boris Chichkov Peter Behrens 《Journal of Materials Science》2009,44(24):6490-6497
In this work, the preparation of three-dimensional hierarchical pore structures by a combination of laser-based templates
and the self-organization process of mesostructured titania is presented. For this purpose macrostructured polymers produced
by two-photon polymerization act as a template for the deposition of a mesostructured titania film from a solution containing
an amphiphilic block copolymer by dip coating. A carefully applied calcination procedure removes both the macrotemplating
polymer and the mesotemplating surfactant molecules so that a replica of the initial polymer structure with a hierarchical
(macro- and meso-) pore system is obtained. In addition, the titania, which is amorphous after deposition, is transferred
into crystalline anatase during calcination. Materials with dual pore systems are interesting for possible applications in
catalysis and sorption, and three-dimensional crystalline structures from materials with high refraction index are attractive
for photonic applications, for example as photonic crystals. 相似文献
100.
Thickness of eggshell fragments and whole eggs from the Peregrine Falcon Falco peregrinus collected in South and West Greenland between 1972 and 2003 was measured and compared to shell thickness of pre-DDT eggs, also collected in Greenland. Linear regression yields a significant increase in the average thickness of eggshells over the period of 0.19% per year, corresponding to a change in eggshell thinning from 13.9% in 1972 to 7.8% in 2003. Backwards extrapolation of the data, suggests that the Greenlandic Peregrine population probably was never critically affected by DDT-induced eggshell thinning. By sampling eggshell fragments in many nests the spatial and temporal sample distribution was enlarged, allowing the detection of a significant long-term decrease in pollutant-induced eggshell thinning--a trend that could not have been identified if only the rarer whole, addled eggs had been sampled. 相似文献