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31.
以溴和苯基取代的对苯二甲酰氯及2,2′-二甲基联苯-4,4′-二甲酰氯作为单体,分别与甲基、叔丁基、苯基取代的对苯二酚经熔融缩聚反应,合成一类具有刚性棒状结构的全芳香液晶聚酯。聚酯的热性质以TGA、DSC,热台偏光显微镜研究。所有的聚酯均为热致性液晶,它们具有相对较低的转变温度,在普通的有机溶剂中具有较好的溶解性质。 相似文献
32.
A microbubble-powered bioparticle actuator 总被引:4,自引:0,他引:4
Maxwell R.B. Gerhardt A.L. Toner M. Gray M.L. Schmidt M.A. 《Journal of microelectromechanical systems》2003,12(5):630-640
We present the results of a device that uses controllable microbubble actuation to manipulate bioparticles. In order to create a useful device for controlling the position of bioparticles, predictable microfluidic actuation is crucial. The goal of this project was to develop fundamental technology that can be used to manipulate single bioparticles (e.g., cells). We use a thermal bubble actuation method to accomplish this goal. Microbubbles have the advantages of relatively simple electronics and fabrication but can be difficult to control. In this paper, we describe two specific accomplishments: the use of micromachined nucleation cavities to precisely localize thermal bubbles and to achieve controllable bubble formation temperatures and bubble dissipation and the demonstration of controllable microbubbles in a new device for particle sorting. 相似文献
33.
The procedure of testing adhesives for glulam production depends in Europe on the kind of resin. For example the testing of phenol-formaldehyde resins (PF-resins) includes the boiling test method, because the curing rate of these resins show a significant correlation between the strength after boiling and the resistance to moisture influence. On the other hand this test method is commonly insufficient for testing other resins. The results of investigations of glulam based on different kinds of resins show that there is a possibility to substitute the boiling test by a short-time accelerated aging method (KZB-Test) which will offer the same differentiation. 相似文献
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35.
Pin&Play: the surface as network medium 总被引:2,自引:0,他引:2
Van Laerhoven K. Villar N. Schmidt A. Gellersen H.-W. Hakansson M. Holmquist L.E. 《Communications Magazine, IEEE》2003,41(4):90-95
Integrating appliances in the home through a wired network often proves to be impractical: routing cables is usually difficult, changing the network structure afterward even more so, and portable devices can only be connected at fixed connection points. Wireless networks are not the answer either: batteries have to be regularly replaced or changed, and what they add to the device's size and weight might be disproportionate for smaller appliances. In Pin&Play, we explore a design space in between typical wired and wireless networks, investigating the use of surfaces to network objects that are attached to it. This article gives an overview of the network model, and describes functioning prototypes that were built as a proof of concept. 相似文献
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R Albrecht TC Awes C Baktash P Beckmann F Berger R Bock G Claesson G Clewing L Dragon A Eklund RL Ferguson A Franz S Garpman R Glasow HA Gustafsson HH Gutbrod J Idh P Jacobs K Kampert BW Kolb P Kristiansson IY Lee H Loehner I Lund FE Obenshain A Oskarsson I Otterlund T Peitzmann S Persson F Plasil AM Poskanzer M Purschke H Ritter S Saini R Santo HR Schmidt T Siemiarczuk SP Sorensen E Stenlund ML Tincknell GR Young 《Canadian Metallurgical Quarterly》1991,44(6):2736-2752
38.
To determine the most effective treatment for acrodermatitis chronica atrophicans, several clinical trials were undertaken in recent years to evaluate whether a 2-week course of ceftriaxone would be superior to oral antibiotics. Of the 46 patients suffering from acrodermatitis chronica atrophicans, 14 were treated with ceftriaxone 2g for 15 days. The remaining patients received either oral penicillin V 1.5 million IU t.i.d. or doxycycline 100 mg b.i.d. for 20 to 30 days. Patients were followed up for at least 1 year. Of the 14 ceftriaxone-treated patients four showed incomplete regression of the inflammatory skin changes after 6 to 12 months. Two out of five patients who were monitored for Borrelia burgdorferi DNA excretion were still positive after 12 months as compared to none of six patients who were treated orally for 20-30 days. Six out of 11 patients treated orally for only 20 days needed retreatment after 6 months because of continuing skin manifestations, neuropathy or arthralgia. A 30-day duration of treatment with oral antibiotics and not the chosen antibiotic is crucial for curing acrodermatitis chronica atrophicans. The duration of treatment with ceftriaxone needed for eradication of Borrelia in acrodermatitis chronica atrophicans has yet to be determined in future studies. 相似文献
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Employing retinal explants and retrograde transport techniques, we studied the formation of the arcuate fascicles by examining the growth of the central retina, the emergence of the adult fiber layer pattern, and the projections of retinal ganglion cells in the central and peripheral retina. Sixty days prior to foveal pit formation, the distance from the incipient fovea to the optic disk was equal to the adult, even though the retinal area was only 8% of the adult. Arcuate fibers, at this age, were observed to avoid the incipient fovea, with no fascicles and few axons projecting over this region. A small population of 15.2% of the ganglion cells located within 2 mm of the incipient fovea possessed an axon with an aberrant trajectory that wound around and projected 50 to several hundred microns away from the optic disk, compared to only 3% at other retinal locations. The incidence of disorder decreased with increasing fetal age, establishing mature values in late fetal periods. These findings suggest that the area of the central retina does not increase after embryonic day 60 and that guidance factors are present that allow outgrowing ganglion cell axons to distinguish and avoid that portion of the retina that will become the fovea. 相似文献