排序方式: 共有12条查询结果,搜索用时 140 毫秒
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Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH. 相似文献3.
We have built a 1000mum-diameter silicon nitride deformable mirror for focus-control applications, using micro-optoelectromechanical systems technology. We achieved variable focal lengths from 36 to 360 mm while maintaining zero primary spherical aberration, using a maximum control voltage of 100 V. Active control of spherical aberration of approximately two waves at 660 nm was demonstrated. 相似文献
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KM Varier AM Vinodkumar NVSV Prasad PV Madhusudhana Rao DL Sastry Lagy T Baby MC Radhakrishna NG Puttaswamy JJ Das P Sugathan N Madhavan AK Sinha DO Kataria 《Pramana》1999,53(3):529-533
Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies.
Coupled channel calculations incorporating couplings to 2+ and 3− states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements
had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer
were carried out for 46,48Ti+61Ni systems. The present paper gives the results of these studies. 相似文献
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WYETH Paul 《中国科学:化学》2010,(3)
Silks represent some of the most precious ancient and historic textile artefacts in collections worldwide.Their optimum preservation demands an appreciation of their characteristics.One important concern,especially with regard to ancient Chinese silks,is whether the fabrics have been degummed.Silks with remnant sericin gum coating the fibroin fibres would require different conservation protocol.In previous research on aged silks,the presence of sericin has been inferred from amino acid analysis of hydrolysa... 相似文献
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Confocal enhanced optical coherence tomography for nondestructive evaluation of paints and coatings 总被引:1,自引:0,他引:1
We investigate confocal enhanced optical coherence tomography as a nondestructive evaluation tool for imaging with improved image contrast and depth resolution through a highly scattering paint layer. The depth responses provided by confocal microscopy, optical coherence tomography, and confocal enhanced optical coherence tomography for imaging through paint are investigated. We demonstrate that a new combination of confocal microscopy and optical coherence tomography provides significantly improved resolution and contrast for coherence gated imaging of substrate structures under the paint. 相似文献
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[formula: see text] Iron salts efficiently catalyze the Doyle-Kirmse reaction of allyl sulfides with (trimethylsilyl)diazomethane and ethyl diazoacetate in dichloroethane at 83 degrees C. Competitive dimerization is less of a problem with (trimethylsilyl)diazomethane than with ethyl diazoacetate. Good results are obtained using only 1.5 equiv of (trimethylsilyl)diazomethane, even without slow addition. Phosphine ligands affect the kinetics, but not the diastereoselectivity. Dppe and BINAP lead to higher yields than dppp, but no enantioselection was detected with R-(+)-BINAP. 相似文献
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Yang VX Mao Y Standish BA Munce NR Chiu S Burnes D Wilson BC Vitkin IA Himmer PA Dickensheets DL 《Optics letters》2006,31(9):1262-1264
An elliptical microelectromechanical system (MEMS) membrane mirror is electrostatically actuated to dynamically adjust the optical beam focus and track the axial scanning of the coherence gate in a Doppler optical coherence tomography (DOCT) system at 8 kHz. The MEMS mirror is designed to maintain a constant numerical aperture of approximately 0.13 and a spot size of approximately 6.7 microm over an imaging depth of 1mm in water, which improves imaging performance in resolving microspheres in gel samples and Doppler shift estimation precision in a flow phantom. The mirror's small size (1.4 mm x 1 mm) will allow integration with endoscopic MEMS-DOCT for in vivo applications. 相似文献