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This paper reports a method to produce networks of crystalline gallium oxide comprised of one‐dimensional (1D) nanostructures. Because of the unique arrangement of wires, these crystalline networks are termed as ‘nanowebs’. Nanowebs are of great technological interest since they contain wire densities of the order of 109 cm–2. A possible mechanism for the fast self‐assembly of crystalline metal oxide nanowires involves multiple nucleation and coalescence via oxidation–reduction reactions at the molecular level. The preferential growth of nanowires parallel to the substrate enabled them to coalesce into regular polygonal networks. The individual segments of the polygonal network consist of both nanowires and nanotubules of β‐gallium oxide. Individual wire properties contribute to a nanoweb’s overall capacity and the implications for devices based on nanowebs are expected to be enormous. 相似文献
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Thirty-two consecutive patients with haematological disorders, in need of a permanent central venous catheter (CVC) were randomly allocated to have their CVC bandages (Tegaderm) changed once (OAW, n = 20) or twice (TAW, n = 19) a week. The two randomization arms were balanced in respect of age, sex, and underlying disease. The exit site of the CVC was inspected daily through the transparent bandage and erythema was noted. If severe erythema occurred, daily wet gauze dressings were applied. Samples for bacterial cultures were taken from the exit site of the CVC at every change of bandages. There was no difference in complications leading to removal of the CVC between the two groups (7/20 OAW vs. 7/19 TAW) or in CVC survival-time (P = 0.4). However, the OAW group had more positive CVC tip cultures (OAW 11/14 vs. TAW 2/9; P < 0.05) and a tendency to: (i) more extra dressings (P = 0.08); (ii) more cultures from the exit skin site showing high numbers of colony forming units (P = 0.07); (iii) shorter time to first exit site infection (P = 0.09); and (iv) more Gram-positive septicaemias (P = 0.08). Both clinical and bacteriological data in this study indicate that changing transparent polyurethane CVC bandages twice a week is superior to once a week. 相似文献
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Switched reluctance (SR) motors with differing structures are compared in terms of their torque prediction capabilities. The first structure is doubly salient with conventional laminations, also referred to as the CRS motor. The second has semiclosed stator slots and a cylindrical rotor with anisotropic magnetic properties arising from axial laminations interleaved with nonmagnetic material, also referred to as the CRR motor. The second structure has been claimed, on theoretical grounds, to be the superior structure in terms of torque per stator volume. The present comparison, based on RMS currents, concludes that the torque produced by the conventionally laminated motor is approximately 2.5 times that of the anisotropic design when the two copper losses are equalized. However, when the CRR motor has been optimized in terms of magnetic and electric loading, the CRS motor is still twice as torque productive. These results reverse the benefits previously claimed for the anisotropic motor design 相似文献
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Antidepressant-induced adverse sexual effects are becoming more frequently reported by patients who require pharmacotherapy. A MED-LINE search was conducted to generate articles reporting such events. We report here on the sexual side effects associated with tricyclics, monoamine oxidase inhibitors including moclobemide, selective serotonin reuptake inhibitors, bupropion, and on the newer antidepressants venlafaxine and nefazadone. We conclude that adverse sexual effects are an increasingly important side effect of antidepressant medications, and patients must be routinely asked about their occurrence. 相似文献
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