排序方式： 共有9条查询结果，搜索用时 15 毫秒
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以FeCl3?6H2O、NiCl2?6H2O、MgCl2?6H2O为原料，以NaOH为沉淀剂采用水热法合成了镁镍铁水滑石 (MgNiFe-LDH)，通过X射线衍射 (XRD)、傅里叶变换红外光谱 (FTIR) 和扫描电镜 (SEM) 分析了MgNiFe-LDH结构及形貌，探讨了不同陈化时间和水热温度对MgNiFe-LDH合成的影响。将制得的MgNiFe-LDH添加至聚丙烯 (PP) 中，制备MgNiFe-LDH/PP复合材料，通过对材料的加速老化测其力学性能，研究了添加MgNiFe-LDH前后材料力学性能的差异。研究结果表明，当Mg2+:Ni2+:Fe3+=2:1:1，反应温度为140℃、陈化时间为24 h时，合成的MgNiFe-LDH为片状，形貌较为规整，颗粒粒径约为2μm；经加速老化后，填充MgNiFe-LDH 复合材料的抗老化性能优于纯PP，当MgNiFe-LDH的填充量为6 wt% 复合材料拉伸强度不变，可明显提高PP的抗老化性能。 相似文献
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The paper presents a theoretical and an experimental investigation into the buckling of seven oblate hemi-ellipsoidal dome shells under external hydrostatic pressure. Four of the shells were made in glass reinforced plastic and three were made from a thermosetting plastic called solid urethane plastic. All the vessels were tested to destruction. The theoretical study was made with the aid of a non-linear finite element solution, where both geometrical and material non-linearity were allowed for. Good agreement was found between experiment and theory for all the vessels. The very oblate domes failed axisymmetrically. Theoretical convergence was good for the more oblate domes but it was not as good as for the less oblate domes. This may have been because the less oblate domes did not fail in a classical axisymmetric manner as was expected. This work is of much importance in ocean engineering. 相似文献
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Carl T.F. Ross 《Ocean Engineering》2006,33(16):2087-2104
The paper presents a conceptual design of an underwater star wars’ system, which will be more difficult to detect by the enemy than a recently proposed ‘surface’ star wars’ system.The paper suggests that for the proposed structures needed for the underwater star wars’ system, the material of construction should be a composite and not a metal, as use of the latter for large deep diving underwater vessels will result in such structures sinking to the bottom of the ocean like stones, due to the fact that they will have no reserve buoyancy. The paper also shows that composites have better sound absorption characteristics, thereby making the underwater structures difficult to detect through sonar equipment. It is proposed that these underwater structures should operate up to a depth of 7.16 miles (11.52 km), as at this depth, all of the oceans’ bottoms can be reached.The author shows that current technology can be used to construct and operate such vessels, but more progress needs to be made with metal matrix and ceramic composites, so that the hulls of underwater missiles and torpedoes can be constructed in these materials. 相似文献
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This paper deals with the static structural test of 1.5-ton test WIG (Wing-In-Ground effect) craft designed and built to verify its aero/hydro-dynamic and structural design characteristics prior to the design of full scale 20-passenger WIG craft. The test WIG craft is scaled down from its full scale WIG craft by 1/2 and built using pre-preg carbon/epoxy composites for the majority of structural parts with metallic materials for fittings used at wings to hull connections. To initiate the test, the finite element (FE) models of the test WIG craft are developed and, based on their results, the details of applied load range, strain/deflection gauge types and locations, load application methods and data acquisition system specifications are determined. The test is performed with respect to main wings to hull connection part first and then vertical tail wing to hull connection part and, finally, horizontal tail wing to vertical tail wing/hull connection part. Both the test and FE model results are compared with respect to stresses and deflections and the comparison shows good correlation between them which implies satisfactory design and building of 1.5-ton test WIG craft. 相似文献
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采用沉淀法合成了镁镍铝水滑石 (MgNiAl-LDH)，研究了不同尿素和水热温度对合成MgNiAl-LDH的影响。通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和扫描电镜（SEM）对MgNiAl-LDH进行了表征。将制得的MgNiAl-LDH添加至聚丙烯中（PP）中，制备MgNiAl-LDH/PP复合材料，通过加速老化及力学性能测试考察了MgNiAl-LDH的添加量对复合材料性能的影响。研究结果表明，当Mg2+:Ni2+:Al3+为2:1:1，反应温度为100℃、尿素用量为二价金属阳离子 (Mg2++Ni2+) 摩尔浓度的2.5倍时，合成结晶良好的MgNiAl-LDH。复合材料耐老化实验结果表明：当MgNiAl-LDH的填充量为6 wt%时，经加速老化后，MgNiAl-LDH/PP复合材料拉伸强度基本保持不变，抗老化性能明显。 相似文献
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