轧钢加热炉液压推钢机的设计应用

针对石横特钢一轧车间加热炉推钢机运行可靠性差 ,工作部件磨损严重、维修与调整工作量大等问题 ,对原机械式传动推钢机进行了改造。重点介绍了液压推钢机的传动原理及在设计过程中需要注意控制的关键问题 ,可供在同行业加热炉中借鉴。     

锰硅合金冶炼渣型的研究与控制

简要论述了锰硅合金冶炼的渣型特征及其控制方法。     

Effect of Rare Earths on Corrosion Resisting Properties of Carbon-Manganese Clean Steels

Rareearthelementshavesignificantactionsinsteels ,includingwipingoffimpurityelements ,trans modifyinginclusions ,andimprovingmicrostructureetal,soaddingappropriaterareearthsintosteelscanef fectivelyimprovetheircorrosionresistingproper ties[1,2 ] .Todaypuri…     

Modeling and analysis of workpiece stability based on the linear programming method

After being located on a machine bed, a workpiece will be subject to gravity and cutting forces during the machining operation. In order to keep the locating precision as well as the production safety, it is necessary to maintain the workpiece stability. In this paper, a linear programming method is proposed for stability analysis of the workpiece. Based on the linear approximation of the friction cone, a quantitative criterion is established to verify the workpiece stability in association with the rationality of the clamping sequence, magnitude of clamping forces and clamping placement. This criterion allows designers to plan reasonably the clamping sequence, magnitude of clamping forces as well as clamping placement. Compared with existing methods, the main advantage of this approach lies in that the sophisticated computing of contact forces between fixture elements and the workpiece is avoided. In this work, both friction and frictionless cases can be easily taken into account in stability analysis. Mathematical formulations of the method are given and some numerical tests are finally demonstrated to validate the proposed method.     

环境美学视野中的山水城市理念

从阐述宜居城市的内涵出发,提出乐居是宜居的最高境界,并进而在此基础上,透过环境美学的视野,分析了山水城市理念与城市乐居追求的内在关联,指出环境美学试图营造的让人乐居的理想居住环境,实际上与山水城市的理念殊途同归．     

福建连城锰矿在困境中求发展

通过分析近几年制约矿山发展的因素,提出了一系列克服困难的对策,值得多数矿山借鉴。     

双能X线吸收法与近红外法测定脂肪含量的评价

用美国Ｌｕｎａｒ ＤＰＸ－Ｌ骨密度仪和日本ＦＶＴＲＥＸ－１０００型近红外仪对９２例人群进行脂肪含量评价。其中７８例为健康人，男性４３例，女性３５例。测定结果女性平均脂肪含量高于男性，两种方法对全部人群的体脂肪测定结果相关系数ｒ＝０．９２１，本文介绍测定原理并对两种方法的优缺点作了评价。     

中国参考人系列模型的建立及外照射剂量学特征的研究

为探讨不同人种、不同姿势及新的组织权重因子对人体剂量学的影响,建立了基于GBZ/T200的中国参考人系列模型（包括立姿、坐姿、走姿的男女模型）;结合蒙特卡罗程序计算得到不同射线能量、6种标准照射方式下的器官吸收剂量和有效剂量。结果表明,基于不同权重因子和不同种族参考模型可得到不同的有效剂量,尤其是低能阶段的差异较为明显;姿势的改变使得器官剂量和有效剂量有所变化,主要由于器官之间的屏蔽作用,体现在相对立姿时坐姿前后照射的有效剂量减小和走姿左右照射的有效剂量增加。进行辐射剂量学评估时,在低能阶段不同的影响因素对结果有较大的影响,而高能时不太明显,因此在进行医学影像等复杂辐射场的辐射防护工作时应注重实际情况的考虑。     

Nitrogen utilization and transformation in red soil fertilized with urea and ryegrass

The influence of fertilization with urea and ryegrass on nitrogen utilization and transformation in red soil has been studied by using ^15N tracer method.When urea and ryegrass were applied alone or in combination,the percentage of N uptaken by ryegrass from labelled urea was 3 and 1.7 times that from labelled ryegrass for the application rate of 200mgN.kg^-1 and 100mgN.kg^-1,respectively;combining application of ryegrass and ureareduced uptake of urea N and increased uptake of ryegrass N by ryegrass plant,but the percentage of N residued in soil increased for urea and decreased for ryegrass.when urea and ryegrass were applied alone,the percentage of N residued in soil from labelled ryegrass was more than 69% while that from labelled urea was less than 25%,and much more ryegrass N was incorporated into humus than urea N.     

血液中铀的测定与探讨

本工作采用裂变径迹技术测定人体血液中的微量铀,血样品直接从健康者、从事铀研究的工作者和白血病患者的手指中取样(20μl),试图确定人体血液中微量铀的统计分布。实验测得健康者血液中微量铀的平均值为(3.06±0.10)×10~(-10)g/ml;从事铀工作者血液中微量铀的平均值为(4.53×0.12)×10~(-10)/ml;而白血病患者血液中微量铀的平均值为(7.74±0.15)×10~(-10)g/ml,是健康者2.5倍。所提供的方法灵敏度高、采血量少,对铀矿工作者职业保护有实用意义,并为寻找理想的解毒和促排药物提供可靠的依据。