CYTJ45掘进钻车用钎杆应力和凿入效率分析

针对CYTJ45液压钻车凿入系统,应用冲击波理论和累积损伤理论进行了钎杆应力计算、寿命估测和凿入效率分析,并和气动凿岩机凿入系统做了比较。研究表明:采用液压凿岩机时,在传递大冲击能量情况下,钎杆应力峰值降低,钎杆凿入效率和工作寿命显著增大。文中阐明了采用液压凿岩机的冲击凿入系统在能量传递方面具有明显的优势。

盐碱胁迫下不同棉花品种植株形态及产量的变化

为明确土壤盐碱化抑制不同棉花品种生长发育情况并揭示不同棉花品种耐盐碱能力的差异,本研究以8个新疆耐盐碱能力不同的棉花品种为试验材料,在大田两个盐碱梯度(高:pH值8.5;低:pH值7.9)下,测定和分析棉花萌发过程中成苗率,初花期与盛铃期的农艺性状(株高、茎粗、果枝台数、蕾花铃、脱落数)、光合特性(净光合速率、气孔导度、胞间CO_(2)浓度、蒸腾速率)及产量。结果发现,高浓度胁迫下棉花的成苗率及株高、茎粗、果枝数、蕾花铃数等形态指标分别比低浓度处理低27.5%、17.54%、6.27%、7.12%和5.51%。盛铃期高浓度下高耐盐碱品种的净光合速率比耐盐碱品种和敏盐碱品种分别高12%和21%;而低浓度下高耐盐碱品种的净光合速率比耐盐碱品种和敏盐碱品种分别低9%和4%。高盐碱胁迫下敏盐碱品种L18的皮棉产量受盐碱抑制程度高达48%,耐盐碱品种仅有3.8%。相关性分析表明:籽棉产量与成苗率、初花期株高、茎粗、气孔导度、胞间CO_(2)浓度、蒸腾速率呈极显著正相关,与盛铃期株高、茎粗、果枝数呈极显著正相关,与光合呈负相关;皮棉产量与成苗率、株高、茎粗、净光合速率、气孔导度、胞间CO_(2)浓度、籽棉产量呈极显著正相关。综上,同一盐碱胁迫下,高耐盐碱品种在初花期与盛铃期均保持较高光合作用,更利于光合产物的积累,能维持棉花正常的生长发育,减少产量损失。

应力波法测试液压凿岩机的应用

冲击能量是凿岩机最重要的性能指标。近年来在国内外已广泛采用应力波法测定凿岩机的冲击能量,本文介绍了应力波法液压凿岩机测试系统,应用该系统测试了DZYG38B液压凿岩机,对实验结果进行了分析,提出了该液压凿岩机配套液压钻车上使用的建议。

凿岩机及冲击类工具应力波法测试技术

目前国内广泛应用应力波法检测凿岩机等冲击类机具的冲击能量,此方法是国际标准(ISO 2787-1984)和国家标准(GB/T 5621-2008)规定的冲击能量试验方法。本文介绍了气动凿岩机和液压凿岩机及冲击类工具应力波法性能参数测试系统,作为应用这些系统的实例,给出气动和液压凿岩机及气镐、电锤连续25次冲击的测杆最大应力、冲击能量和冲击频率测试结果,展现了这些系统实物的图片,为凿岩机及冲击类工具应力波法测试技术的发展提供参考。

Improvement of Wear Resistance of Magnesium Alloy AZ91HP by High Current Pulsed Electron Beam Treatment

Surface modification of magnesium alloy AZ91HP (9wt%Al, 0.5wt%Zn, 0.5wt%Mn, Mg remaining percentage) by high current pulsed electron beam (HCPEB) treatment was studied in this paper. The secondary phase MgnAln is nearly completely dissolved and as a result, a super-saturated solid solution forms on the re-melted surface. The microhardness is increased both in and far beyond the heat-affected zone (HAZ), reaching about 250um. Measurements on sliding wear have shown that the wear resistance of the treated samples was improved by a factor of about 2.4 as compared to the as-received sample. It is also found that the sliding wear resistance can be further improved by surface alloying with TiN.

Improved Corrosion Resistance of Magnesium Alloys AZ31 and AZ91HP by High Current Pulsed Electron Beam Treatment

Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl solution, showing remarkably improvement as manifested by polarization curves. According to EPMA analysis, the intermetallic Mg17Al12 in the surface layer of AZ91HP sample almost disappeared after the treatment of HCPEB, leaving the surface layer in a state of supersaturated solid solution. Both the augmentation of aluminum content and the formation of supersaturated structure in the surface layer are believed to contribute to the improved corrosion resistance of AZ31 and AZ91HP.

新砦期农业经济研究--花地嘴遗址炭化植物遗存分析

新砦期是龙山向二里头时代转变的过渡时期。目前有关新砦期遗址炭化植物遗存研究已经有了一定程度的进展,如新密新砦和郑州东赵遗址的植物遗存研究成果业已公开发表。本文以介绍花地嘴遗址浮选结果为切入点,结合新砦和东赵遗址的研究成果,系统分析了中原腹地郑州地区新砦期的农业经济特点。这对观察过渡时期中原腹地农业经济与文明发展之间的关系具有重要意义。