防止椭圆-圆孔型系统轧件发生扭转的措施

八钢小型轧钢厂中、精轧采用椭圆一圆孔型系统在生产过程中多次发生轧件扭转，经分析认为圆孔型入口导卫磨损的程度直接影响轧件扭转程度和产品质量。为防止轧件产生扭转，将入口导卫椭圆导辊改成菱形导辊，解决了轧件扭转的问题。     

H型钢侧向矫正中的扭转问题研究

应用弹性和弹塑性扭转理论,对H型钢在侧向矫正中的扭转变形进行了计算,给出了扭矩与扭转变形(扭转角)之间的关系。通过型钢所受扭矩大小或产生的单位扭转角的大小可以判断轧件产生的扭转变形的类型。通过典型规格H型钢的扭转研究,认为侧向矫直中的侧向扭矩将主要引起轧件的断面变形和腹板上接触力分布的变化。轧件的整体扭转力矩仅占其中很小部分,而纯粹的侧向矫直则因扭转失稳无法完成。     

棒线材粗中轧多线大扭转辊的设计与改进

在轧辊呈水平布置的棒线材粗、中轧,由于轧件断面较大,轧件扭转时需要施加较大的扭转力,对扭转辊的设计和使用都提出了较高的要求.本文介绍了安钢Φ260mm机组多线大扭转辊装置的设计及使用情况.改进后,一套大扭转辊能连续上线使用一个月,较原来的小扭转辊寿命提高90倍.     

球扁钢轧制扭转变形行为的试验研究

球扁钢由于自身形状尺寸、外在轧制条件、工艺参数的影响,在轧制过程中容易出现扭转变形缺陷.为了探究轧制工艺对球扁钢轧制中扭转变形的影响,本实验运用正交实验法研究轧制压下量、轧制润滑条件、轧件长度三者的综合影响.利用正交原理对试验结果进行极差分析、方差分析,探寻球扁钢在轧制的扭转变形规律,找出其中存在的关系.试验结果表明:球扁钢在轧制过程的扭转变形与轧制压下量和轧件长度有关,而与润滑条件无明显关系.其他条件一定时,在粗孔第二道次时取压下量为轧件原始厚度的21!,轧件长度取轧件原始厚度的10倍进行轧制,能够明显减少球扁钢的扭转变形.     

出口滑动扭转导卫的设计与应用

通过对轧件在滑动扭转导卫中的受力分析,论述了扭转导卫有关参数的确定,并简要介绍了新型复合材料导卫的制造加工和使用。     

扭转辊的设计与应用

在粗轧机组全水平布置的线棒材连轧生产线中,轧件从随圆孔进入圆形孔需要扭转,采用扭转辊取代扭转导卫,提高抗冲击性,减少少堆钢事故。本文着重介绍了扭转辊的设计方法和应用效果。     

异型门架型钢轧制过程稳定性模拟

借助有限元分析软件对C160规格异型门架型钢的非对称切分孔轧制过程进行模拟仿真,并对轧制过程的翘扣头、弯曲、扭转等稳定性进行模拟。对稳定轧制阶段截面云图中应变分布、变形及延伸进行分析,并进行生产实施,结果表明：轧制过程中,稳定阶段轧件截面下部变形及延伸大于上部应变,造成轧件上翘;左侧变形及延伸大于右侧应变,造成轧件向右侧弯;对角的应变分布及延伸相近,轧件没有发生明显扭转。为轧制过程稳定性研究提供了一种方法,对保证轧制顺行、稳定工艺、提高作业率及指导生产具有重要意义。     

连轧机多线整体辊式扭转器

鞍山钢铁公司研制成功一种连轧机多线辊式扭转器。该扭转器主要由框架、压下螺丝、轴承、轴杆、扭转辊、导槽和调整斜铁等组成。整体安装在轧机出口的牌坊架内。为适应不同断面轧件的要求,其两个扭转辊的径向及轴向尺寸可分别靠压下螺丝和调整斜铁调整,并且在扭转辊与轴杆间采用滚动轴承和甘油润滑。该装置结构简单、紧凑、固定牢固、工作可靠、调整灵活、换辊方便;摩擦系数小,承受扭矩大;孔型合理、开口度大、初始扭转角小、变形缓和、轧件稳定,适用范围广。因此,减少了生产事故,提高了作业率,减少了轧废,从     

楔横轧凸轮轴金属流动规律的有限元分析

通过有限元仿真楔横轧凸轮轴时在轧件上取跟踪点,跟踪这些点的位置变化情况来揭示轧件内金属的详细流动规律.因凸轮体小圆端部分在轧制过程中所受模具挤压较小,其金属轴向流动和径向流动较其他变形区小,这种金属流动的不均匀性会影响轧件成形质量;轧制过程中因凸轮体小圆端与模具上凸轮凹槽产生啮合作用,这一作用降低了模具对凸轮体小圆端部分的周向扭转力,因此凸轮体小圆端部分的周向扭转相对较小.轧件凸轮体部分为非圆截面,此部分各向金属流动不均匀,造成凸轮体部分心部金属偏移量比其他部分大.     

履带钢轧制过程有限元仿真

履带钢断面形状复杂,轧制过程中容易出现扭转、翘曲、侧弯等现象,影响轧制的顺行.利用仿真软件建立了履带钢切深孔轧制过程有限元仿真模型,研究孔型参数对轧件扭转、翘曲及侧弯的影响规律.针对履带钢切深孔轧制扭转严重的问题,优化孔型参数,使履带钢切深孔轧制过程扭转角从135.6°减小到13.85°,满足后续道次正常咬人的要求,保证了生产的顺利进行.     

Standards of weight and height for Ayrshire, brown Swiss, and milking shorthorn heifers

To develop a modern appraisal of growth for Ayrshire, Brown Swiss, and Milking Shorthorn dairy heifers, data on heart girth and height at withers were collected from 1279 Ayrshire heifers (33 herds), 1819 Brown Swiss heifers (46 herds), and 565 Milking Shorthorn heifers (20 herds), ages 1 to 25 mo, in herds located throughout the US. Means and standard deviations were determined for height and heart girth for each month of age. Third-order regressions on age were fitted to the means to describe height and heart girth. Estimated mean height and heart girth at 6, 12, 18, and 24 mo, in centimeters, were for Ayrshire 98.7 and 118.4, 114.4 and 145.9, 122.8 and 163.2, and 127.6 and 176.4; for Brown Swiss 102.6 and 122.3, 199.4 and 151.3, 128.7 and 168.8, and 134.0 and 182.0; and for milking Shorthorn 98.0 and 119.4, 113.6 and 148.6, 122.6 and 166.6, and 127.7 and 179.9, respectively. These data can be useful to evaluate the heifer rearing program with respect to the growth rates of heifers on an individual farm.     

钢铁企业智慧能源管控系统开发与实践

 能源管控系统是国家工信部推出的节能减排先进适用技术之一,也是企业实现能源精细化管理的重要措施。综述了钢铁企业能源管控系统的现状和存在的问题,并对未来发展进行了展望。针对能源管控系统核心功能展开进一步分析,从基础能源管理到能效分析与评价、能源供需预测与优化分配、多能源介质耦合优化调度及辅助决策,以及碳排放分析等核心功能,旨在推进中国钢铁工业能源管控系统的进一步完善,促进智能化、绿色化发展,更好地发挥能源精细化管理作用,为企业节能减排做出更大贡献。     

我国钛及钛合金板材标准化现状

主要回顾了我国钛及钛合金板材标准化历程,重点介绍了本世纪钛板材国标体系的重要变化及完善情况,并与国外先进标准进行了对比,提出了进一步完善和发展我国钛板材标准体系的发展思路、改进意见和建议。     

The utility of high-resolution magnetic resonance imaging in the evaluation of the triangular fibrocartilage complex of the wrist

This work offers an anthropological analysis of intra-household processes underlying gender- and age-specific differences in individual nutritional and health care allocations and outcomes in particular cultures. Based on recent ethnographic studies in India, Nepal, Madagascar, Mexico, and Peru, correspondences are analyzed between local cultural ("emic") and scientist-policy maker practitioner ("etic") understandings of nutrition, health, and human development, and the relative "values" of females, males, and children of different ages. The data and analyses clarify specific epidemiological and demographic findings on age and gender bias in nutrition and health and highlight the multiple cultural, economic, and biological factors that contribute to gender- or age-based discrimination or neglect. Recent advances in nutrition policy have argued for a broader concept of nutritional security, one that incorporates both food quantity and quality, and of nutrition as "food, health and care" (International Conference on Nutrition, World Declaration and Plan of Action for Nutrition, FAO/WHO, Rome, 1992). These ethnographic findings; lend strong support for such broader nutrition concepts and associated nutrition policies. The studies also suggest ways in which anthropological questions, methods, and data and community-based research can help predict or identify the nutritionally vulnerable within households and help other social and medical scientists design more effective interventions.     

钢铁制造流程炼铁区段耗散结构的解析

为了研究钢铁制造流程耗散结构的本质及其特征,以高炉炼铁区段为对象,研究解析了多工序协同动态运行条件下的耗散结构优化问题.由料场、焦化、烧结、球团、高炉等工序所组成的炼铁区段,不仅是钢铁制造流程中重要的物质/能源转换中心,也是全流程动态有序、协同连续运行的关键和基础环节.炼铁区段的物理本质是铁素物质流在碳素能量流的驱动和...     

钢铁工业节能减排的历史重任

重点研究了我国钢铁工业节能减排的目标,钢铁工业能耗、污染物排放的现状,我国钢铁工业与国际先进水平的差距及原因,钢铁企业联合重组取得的新进展,主动减排二氧化碳、二氧化硫气体及我国钢铁工业未来的发展方向.     

天铁科技成果管理工作实践

论述了科技成果管理的内容和意义,结合企业实际介绍了天铁科技管理的制度、体系及实施效果。通过科技创新体系和成果管理制度建设,“十一五”期间促进了科技成果的开发和转化,有多个项目分别列人天津市技术创新重点为项目、天津市二十项重点项目,推动了企业持续快速发展。     

Girlfriend, boyfriend: Age and sex differences in intimate friendship.

Investigated changes in intimate friendship with same- and opposite-sex friends in preadolescence and adolescence, using the Intimacy Scale. Ss were Israeli children from the 5th, 7th, 9th, and 11th grades (60 boys and 60 girls from each grade), who rated their friendship with a same- or opposite-sex best friend. There was a significant age difference in overall intimacy with same-sex friends. Frankness and spontaneity, knowing and sensitivity, attachment, exclusiveness, and giving and sharing were factors that changed with age. Trust and loyalty, and taking and imposing did not. Opposite-sex friendship revealed a significant increase in intimacy with age. Boys and girls did not differ in reported opposite-sex friendship in the 5th and 7th grades, whereas girls in the 9th and 11th grades reported higher intimacy than did boys. This sex-by-age pattern of interaction was particularly evident for attachment and for trust and loyalty. Girls were higher in knowing and sensitivity, giving and sharing, and taking and imposing. The implications for further differentiation among types of peer relations and interrelation of dyadic friendship and cognitive growth are discussed. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Paraplane analysis from precordial three-dimensional echocardiographic data sets for rapid and accurate quantification of left ventricular volume and function: a comparison with magnetic resonance imaging

OBJECTIVES: Three-dimensional echocardiography (3DE) calculates left ventricular volumes (LVV) and ejection fraction (EF) without geometric assumptions, but prolonged analysis time limits its routine use. This study was designed to validate a modified 3DE method for rapid and accurate LVV and EF calculation compared with magnetic resonance imaging (MRI). METHODS: Forty subjects included 15 normal volunteers (group A) and 25 patients with segmental wall motion abnormalities and global hypokinesis caused by ischemic heart disease (group B) who underwent 3DE with precordial rotational acquisition technique (2-degree interval with electrocardiographic and respiratory gating) and MRI at 0.5 T, electrocardiogram (ECG)-triggered multislice multiphase T1-weighted fast field echo. End-diastolic and end-systolic LVV and EF were calculated from both techniques with Simpson's rule by manual endocardial tracing of equidistant parallel left ventricular short-axis slices. Slicing from the 3DE data sets were done by both 2.9-mm slice thickness (method 3DE-A) and by 8 equidistant short-axis slices (method 3DE-B); for MRI analysis, 9-mm slice thickness was used. RESULTS: Analysis time required for manual endocardial tracing of end-diastolic and end-systolic short-axis slices was 10 minutes for the 3DE-B method compared with 40 minutes by the 3DE-A method. For all 40 subjects the mean +/- SD of end-diastolic LVV (mL) were 181 +/- 76, 179 +/- 73, and 182 +/- 76; for end-systolic LVV (mL), 120 +/- 76, 120 +/- 75, and 122 +/- 77; and for EF (%), 39 +/- 18, 38 +/- 18, and 38 +/- 18 for MRI, 3DE-A, and 3DE-B methods, respectively. The differences between 3DE-A and 3DE-B with MRI for calculating end-diastolic and end-systolic LVV and EF were not significant for the whole group of subjects as well as for the subgroups. The 3DE-B method had excellent correlation and close limits of agreement with MRI for calculating end-diastolic and end-systolic LVV and EF: r = 0.98 (-1.3 +/- 26.6), 0.99 (-1.6 +/- 21. 2), and 0.99 (0.2 +/- 5.2), respectively. The correlation between 3DE-A and MRI were r = 0.97, 0.98, and 0.98, and the limits of agreement were -1.4 +/- 36, -0.6 +/- 26, and 0.6 +/- 8 for calculating end-diastolic and end-systolic LVV and EF, respectively. In addition, excellent correlation and close limits of agreement between 3DE-A and 3DE-B with MRI for LVV and EF calculation was also found for the subgroups. Intraobserver and interobserver variability (SEE) of MRI for calculating end-diastolic and end-systolic LVV and EF were 6.3, 4.7, and 2.1; and 13.6, 11.5, and 4.7; respectively, whereas that for 3DE-B were 3.1, 4.4, and 2.2; and 6.2, 3.8, and 3. 6; respectively. Comparable observer variability was also found for the A and B subgroups. CONCLUSIONS: The 3DE-A and 3DE-B methods have excellent correlation and close limits of agreement with MRI for calculating LVV and EF in both normal subjects and cardiac patients. The 3DE-B method by paraplane analysis with 8 equidistant short-axis slices has observer variability similar to MRI and reduces the 3DE analysis time to 10 minutes, therefore offering a rapid, reproducible, and accurate method for LVV and EF calculation.     

某复杂难选铅锌氧化矿综合利用项目节能分析

针对氧化矿矿石储量大、品位低、矿石性质复杂、难以选别的特点,介绍了某复杂难选铅锌氧化矿综合利用项目的工艺方案、主要生产指标,提出了各项节能措施,分析了项目的用能总量及主要用能工序,并对项目的能效水平进行了分析.通过开发和采用效率高、节能效果好的工艺流程、设备,并做好建筑、给排水、供配电、通风除尘等辅助和附属设施的节能,...