从病害看钢筋混凝土现浇连续箱梁的防裂设计

通过对某开裂现浇连续箱梁桥的裂缝分析与计算，总结抗裂设计的方法。     

蠕化剂对蠕墨铸铁石墨形态和性能的影响

为满足汽车减轻自身质量和提高性能的要求,将柴油机气缸盖用蠕墨铸铁代替原来的低合金铸铁。主要研究了稀土以及稀土镁加稀土钙和稀土镁加钛铁做蠕化剂对蠕墨铸铁石墨形态和性能的影响。综合考虑石墨形态、性能以及蠕化处理工艺,得到了综合性能好的蠕化剂为稀土镁加钛铁。     

车用发动机球铁曲轴的质量控制

为提高车用发动机球铁曲轴生产技术水平，从铁水的熔炼及炉前处理、造型工艺、浇注一冷却工艺、曲轴强化等方面，对国内外曲轴铸造工艺进行了分析比较。介绍了获得纯净铁水的熔炼方法、铁水的球化处理方法及球化剂的配比、孕育处理方法、铜与钼合金的配合使用方法等。     

无缸套汽车柴油发动机缸体材料的研究与应用

研究了孕育剂和合金元素对灰铸铁性能的影响。试验结果表明：在灰铸铁中加入0．2％～0．25％Cr和0．4％～0．5％Cu，采用60％BaSi 40％SiFe复合孕育剂孕育处理。可以使灰铸铁强度到达250MPa以上。灰铸铁的硬度提高。组织均匀性得到改善。用所研制的铸铁材料制造的无缸套缸体具有良好的强度指标和硬度指标。经激光处理后。缸体具有良好的耐磨性。     

寒区涵洞现浇混凝土基础水化热的影响分析

考虑相变和热量生成，导出了瞬态温度场问题的热量平衡控制微分方程，并用伽辽金法推导出了有限元计算公式。通过对青藏铁路正在修建涵洞的现浇混凝土基础水化热的影响分析，可以看出，现浇混凝土水化热在施工后半年内对涵洞周围冻土的热状况影响较大，施工后2年时仍有影响。为了减小这种影响，还计算分析了涵洞现浇混凝土基础下按2种方式铺设保温材料的冻土热状况。通过分析比较可以看出，在涵洞现浇混凝土基础下铺设保温材料可以大大减少现浇混凝土水化热对冻土热状况的影响。     

铁谱分析在机械设备监测诊断中的应用

基于微粒分析的铁谱技术不仅可以用于磨损机理的研究，而且能对机械设备进行监测和故障诊断。分析了铁谱仪的工作原理及磨损磨粒形式，对这一机械磨损监测诊断的新领域有了一个较为清晰的介绍。     

203型整铸辙叉结构设计及其强度校核

根据203型整铸辙叉结构设计及其整铸成一体的特点,采用有限元软件建立计算模型,分4种工况21个载荷作用点分别进行强度分析,为整铸辙叉的合理设计及结构强化提供理论依据.结果表明:该整铸辙叉心轨与翼轨过渡区通过增设横向筋板进行加强后,各部位强度合格,满足使用要求.     

喷射悬浮孕育对灰铸铁组织和性能的影响

研究了喷射悬浮孕育工艺对灰铸铁石墨形态,基体组织和力学性能的影响。结果表明：采用喷射悬浮孕育处理的效果好于常规冲入法的孕育效果,其石墨尺寸变小,级别提高,基体细化程度增加,力学性能提高,孕育剂加入量一定时,粒度的大小对孕育效果有明显的影响,而孕育剂粒度一定时,随着孕育剂加入量的增加,孕育效果增大。     

钢管砼拱桥管芯砼泵送顶升浇灌（压注）法施工

结合哈同公路牡丹江钢管砼工程实例,重点介绍了管芯砼的泵送顶升浇灌法施工工艺及要点和采用“双掺”技术途径,使用普通水泥与地产砂石材料和不改变砼的常规施工工艺条件配制高强、高性能砼的经验。     

Biogeochemistry of sulfur in a sediment core from the west-central Baltic Sea: Evidence from stable isotopes and pyrite textures

The biogeochemistry of the sulfur cycle in a ca. 5-m-long sediment core from the eastern slope (221 m water depth) of the Landsort Deep in the west-central Baltic Sea was investigated by analyzing the solid phase records of sulfur isotopes and pyrite textures, besides selected main and minor elements. The sediments were deposited during post-glacial history of the Baltic Sea when the basin experienced alteration of brackish (Yoldia Sea, Littorina Sea) and freshwater (Baltic Ice Lake, Ancylus Lake) conditions. The stable isotopic composition of total sulfur was analyzed as a function of depth. In selected samples pyrite (FeS₂), greigite (Fe₃S₄), and barite (BaSO₄) fractions were separated for isotope analyses. Pyrite textures were analyzed by SEM and optical microscopy.Microbial reactions associated with the oxidation of organic matter resulted in assemblages of authigenic sulfide minerals which for the post-Ancylus Lake brackish water environment are dominated by pyrite and for freshwater environments by Fe-monosulfides. The sulfur isotopic composition of the brackish water Littorina Sea sediments (δ³⁴S between −40 and −27‰ vs. V-CDT) is believed to be determined by cellular sulfate reduction rates and reactions involving intermediate sulfur species. The availability of reactive iron and decomposable organic matter as well as sedimentation rate and the chemocline position are important variables upon the δ³⁴S values of sulfides in brackish water environment. The syn-depositional abundance of sulfur and organic matter, and transport of dissolved sulfur species vs. rates of microbial reactions determine δ³⁴S in the freshwater sediments. The upper part of the Ancylus Lake sediments is sulfidized by downward diffusing H₂S and/or sulfate from overlying brackish water sediments. Minor concretionary barite formation in the freshwater sediments is most likely due to the reaction of pore water sulfate diffusing downward from brackish water sediments with barium desorbed from freshwater sediments. The size distribution of pyrite framboids in the brackish sediments indicates that the formation mainly occurred from anoxic pore waters, although some pyrite formation in an anoxic water column cannot be excluded.