1960年前黄河下游河槽淤积物粒径组成分析

利用1999年汛前深层钻孔取样资料和历年淤积实测大断面资料分析出1960年前无三门峡水库影响的“自然”水沙情况下,下游河道主槽淤积物中d≥0.1 mm以上泥沙占50.7%,比1960-1999年大30个百分点,这种泥沙在下游的淤积比高达83.1%,比0.05 mm以上泥沙的淤积比高39个百分点。指出应在黄河中游寻找出0.1 mm以上的粗泥沙集中来源区作为近期水土保持的重点区域。     

Effect of carbide additions on grain growth in TiC−Ni cermets

The growth of carbide particles in TiC-XC-2 vol.% Ni and TiC-XC-30 vol.% Ni alloys, where X=Zr, Cr, W, Ta and Mo, was fitted to an equation of the form d³-d_o ³=Kt. The grain growth behavior during liquid phase sintering at 1673K decreased markedly with the addition of Mo₂C or WC, changed little for TaC, and increased with the addition of ZrC or Cr₃C₂. The grain contiguity decreased with increasing Ni content in the TiC−Mo₂C−Ni alloy and was greater in the alloys with smaller growth rate constant. Consequently, the effect of carbide addition on the grain growth of 2 vol.% Ni alloys was found to be similar to that of 30 vol.% Ni alloys. The grain growth mechanism could be explained by the effect of contiguous carbide grain boundaries in restricting the overall grain growth, as well as the area of the solid/liquid interfaces in the alloy by the usual solution/reprecipitation model.     

埕岛油田东部斜坡带东下段沉积特征及油藏类型研究

埕岛油田东部斜坡带下第三系油藏以三角洲、浊积扇砂体隐蔽油气藏为主，储层埋藏深、厚度变化大，油气成藏复杂。通过对该带的沉积特征、沉积体系和沉积物源的研究，指出其东下段砂体的分布主要受物源和沉积相带两方面控制，砂体只有在有效圈闭情况下才能成藏，并且从构造上总结了三种油藏类型。最后指出该带下一步勘探重点是沿主物源方向展布的、成藏条件良好的各种砂体。     

高温合金表面激光熔敷热障涂层组织结构与氧化性能

采用 5KW连续CO2 激光器对Ni基高温合金上二次重熔NiCoCrAlY和ZrO2 陶瓷层进行了研究。结果表明 :激光快速熔化和凝固获得定向外延生长、紧密堆积的柱状晶氧化锆陶瓷层。NiCoCrAlY结合层与柱状晶之间存在氧化铝层 ,保证了柱状晶与NiCoCrAlY层的联结。扫描电镜和电子探针联合分析发现 ,氧化锆层与NiCoCrAlY结合层、结合层与基体间均为冶金结合。采用化学改性氧化锆消除了涂层裂纹。高温氧化性能测试得出激光重熔试样氧化动力学近似地遵守抛物线速率方程。在 12 0 0℃ ,空气下激光熔敷TBCs 抗氧化性明显高于等离子喷涂TBCs。     

Factors Affecting the Squareness of Hysteresis Loops of Sintered NdFeB Magnets

Investigation into the magnets with different squareness of hysteresis loop (SHL) reveals that the microstructure of sintered NdFeB magnets has great effects on the SHL of the magnets. The abnormal grain growth deteriorates the SHL seriously. The shape of the grain and the grain boundary affect the intensity of demagnetization field, and consequently on the SHL. The added elements have effects on the phase structures and distributions in the magnets, which influences the uniform of demagnetization field.     

K418B合金细晶铸造整体涡轮真空热处理工艺研究

通过力学性能评估和金相组织观察，研究五种热处理制度，两个周期的试验结果，确定了Ｋ４１８Ｂ合金细晶铸造整体涡轮的真空热处理工艺。     

06NiCuCrMoNb钢高温加热时表层铜的行为

将06NiCuCrMoNb钢试样在不同的加热温度保温不同时间后，观察并分析试样表层的形貌和成分。结果表明，在一定条件下铜会扩散进入表层奥氏体晶界，得到沿奥氏体晶界分布的富铜相，并在热变形加工时导致热脆。试验得到了沿奥氏体晶界分布的富铜相与加热温度和保温时间的关系。     

On the dissipation process in Bi2Sr2Ca2Cu3O10 tapes and bulk samples with preferential grain orientation in zero external magnetic field

Current-voltage characteristics of Bi₂Sr₂Ca₂Cu₃O₁₀ tapes and bulk samples with preferentially oriented crystallites have been measured in zero applied magnetic field and for temperatures close to the mean-field critical-temperature,T _c0. It was shown that the power-law dependence,V=AI ^a, valid for two-dimensional systems, does not correctly describe the data, which clearly indicate the existence of a finite critical-current density,J _c. The experimentalI-V curves are fitted quite well with the model which attributes the finite critical-current density to the coupling between the CuO₂ double layers. It was found thatJ _c vanishes at a temperature value belowT _c0. This behavior can result from the occurrence of vortex fluctuation-induced layer decoupling and/or from the contribution of entropy to the vortex unbinding process.     

原料对铁合金冶炼过程的影响

介绍了铁合金冶炼时需要准备的原料，对不合格原料需要进行加工处理，达到合格粒度。并提出了影响铁合金冶炼过程有原料的粒度，配料称量，混合等重要因素。     

34CrMoV结构钢动态再结晶行为研究

应用Gleeble-1500热模拟实验机进行等温压缩试验,研究了变形工艺参数对34CrMoV结构钢动态再结晶行为的影响.结果表明,其流变应力随变形温度升高而降低,随应变速率提高而增大;随着应变速率的降低,应变量的增加和变形温度的升高,动态再结晶速度加快且奥氏体晶粒得到细化.