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61.
晚清漕粮海运与李鸿章的关系密不可分.他通过恢复海运扩大漕粮海运的参与省份,调整海运规章、抚恤海运群体,扶植轮船招商局、促进漕粮运输工具近代化等方式,对漕粮海运的变革产生了全方位影响,成为推动中国社会走向近代的重要人物. 相似文献
62.
元明清时期,京杭大运河的开通,便利了北方政治中心与南方经济中心之间的联系。特别是在明清时期,大运河漕运事关国计。当时政府的诸多治河措施是为确保漕运畅通,加之明代保陵的需要,更使黄河、淮河、运河之间的关系复杂化。封建政府的决策行为使本自独流入海的淮河改道主要由长江入海,使淮河流域成为十年九灾之区。 相似文献
63.
Porous synthetic quartzites and amphibolites, each with faceted pore walls, were synthesized and evaluated to examine the permeability of pore networks similar to those of the lower crust and mantle. Quartzite with a fluid in equilibrium with an Mg–clinopyroxene contained connected networks of pores with a dihedral angle of 30° bounded by walls that were 10–50% faceted. The relationship of their permeability (k) to porosity (φ) is approximated by the previously determined relationship for relatively nonfaceted synthetic quartzite Amphibolite with an HF fluid contained fluorotremolite and a connected network of pores bounded by walls exhibiting 78–90% faceting. These materials showed much lower k for a given φ, with an apparent permeability threshold at φc = 0.04. A curve fit to these data yields The results suggest that moderate faceting has little effect on the transmission of fluids through rocks, but extensive faceting significantly alters permeability. This difference is most likely produced through isolation of the fluid to the grain corners at low φ with extensive faceting. Rocks with pores that tend toward faceting may impede the flow of fluids and melt. 相似文献
64.
Maria Verde Alberto De Bonis Virginie Renson Chiara Germinario Concetta Rispoli Francesco D'Uva Antonella Tomeo Vincenzo Morra 《Archaeometry》2023,65(6):1145-1184
79 samples of black glazed pottery, Terra sigillata, fine common ware, and production indicators were recovered in the archaeological site of Cales and investigated via a multi-analytical program (polarized light microscopy, thermal analyses, XRPD, XRF, FESEM, FESEM-EDS). Among the materials, finds of important production indicators, represented by welded pieces of black glazed pottery and spacers, attest a local production. Polarized light microscopy shows that the inclusions consist of feldspar, quartz, mica, calcite, and lithic fragments of both volcanic and sedimentary nature. Additional information about the mineralogical assemblage comes from the XRPD that revealed the presence of neoformed Ca-silicates, indicating equivalent firing temperatures ranging from 750 to 1050°C. All the samples show a Ca-rich character and an extreme compositional homogeneity, including the production indicators. The comparison with some Ca-rich Campanian clay raw materials shows a greater affinity with the Mio-Pliocene marine clay sediments of the Apennine sector, which include local clays. This allowed us to formulate the first hypotheses about clay sources used to produce fine pottery during the third century BCE to the early imperial period in Cales. 相似文献