高Ba孕育剂在厚大灰铸铁件中的应用

比较了2种含Ba量不同的孕育剂用于厚大灰铸铁机床底座生产的效果,结果显示:采用高Ba孕育剂的单铸试棒力学性能和金相组织优于采用低Ba孕育剂的单铸试棒,而且所生产铸件的本体硬度也明显高于采用低Ba孕育剂的铸件。在不加Cu、Mo等贵重金属合金的情况下,采用w(Ba)量为10%的孕育剂进行包内孕育和浇注随流孕育,可以使铸件力学性能和金相组织均达到HT300的要求,铸件本体硬度为190~220 HB,硬度均匀性好,很好地解决了铸件表面硬度与内部硬度差大的问题。     

New developments in high quality grey cast irons

The paper reviews original data obtained by the present authors,revealed in recent separate publications,describing specific procedures for high quality grey irons,and reflecting the forecast needs of the worldwide iron foundry industry.High power,medium frequency coreless induction furnaces are commonly used in electric melting grey iron foundries.This has resulted in low sulphur(0.05wt.%)and aluminium(0.005wt.%)contents in the iron,with a potential for higher superheating(1,500°C),contributing to unfavourable conditions for graphite nucleation.Thin wall castings are increasingly produced by these electric melt shops with a risk of greater eutectic undercooling during solidification.The paper focused on two groups of grey cast irons and their specific problems:carbides and graphite morphology control in lower carbon equivalent high strength irons(CE=3.4%-3.8%),and austenite dendrite promotion in eutectic and slightly hypereutectic irons(CE=4.1%-4.5%),in order to increase their strength characteristics.There are 3 stages and 3 steps involving graphite formation,iron chemistry and iron processing that appear to be important.The concept in the present paper sustains a threestage model for nucleating flake graphite[(Mn,X)S type nuclei].There are three important groups of elements(deoxidizer,Mn/S,and inoculant)and three technological stages in electric melting of iron(superheat,pre-conditioning of base iron,final inoculation).Attention is drawn to a control factor(%Mn)x(%S)ensuring it equals to 0.03–0.06,accompanied by 0.005wt.%–0.010wt.%Al and/or Zr content in inoculated irons.It was found that iron powder addition promotes austenite dendrite formation in eutectic and slightly eutectic,acting as reinforcement for the eutectic cells.But,there is an accompanying possible negative influence on the characteristics of the(Mn,X)S type graphite nuclei(change the morphology of nuclei from polygonal compact to irregular polygonal,and therefore promote chill tendency in treated irons).A double addition(iron powder+inoculant)appears to be an effective treatment to benefit both austenite and graphite nucleation,with positive effects on the final structure and chill tendency.     

一种基于动态抗体记忆库的免疫优化算法在自动需求响应中的应用

自动需求响应是智能电网与用户实现信息和能量互动的重要实现手段。为解决基于实时电价的自动需求响应技术应用中包含多类负荷用户的电能综合规划问题,建立优化问题的数学模型。针对该模型提出一种基于动态抗体记忆库的免疫优化算法。设计依据二重亲和度阈值检测的抗体记忆库更新机制,在优化结束后能够为用户提供多个备选可行解。采用先验知识疫苗接种的方法,提高算法的求解精度。通过抗体种群的优值马尔可夫链的转移概率分析,证明了算法的收敛性;利用实际算例验证了所提算法的有效性。对比分析的结果表明,所提算法比其他算法具有更好的全局优化能力和搜索效率。     

难焊金属材料电阻点焊熔核孕育处理的机理与效果

应用作者提出的熔核孕育处理新技术对难焊金属材料６５ Ｍｎ、ＬＹ１２ＣＺ点焊接头进行了系统的工艺试验和微观分析,较好地解释和评价了孕育处理可提高点焊接头力学性能的机理和效果：生成和扩大等轴晶组织区、减小和消除熔核薄弱面、晶粒显著细化、抑制宏观缺陷的产生等。     

QT450-10铁素体球墨铸铁的稳定生产

介绍选用T1铁素体球化剂和稳定生产QT450-10铁素体球铁的生产工艺,通过严格选取原材料及铁液化学成分,加强熔炼控制,采用多次孕育方法,生产的铸件铸态延伸率超过10%以上.     

液芯包囊乳酸菌用于牛奶连续接种条件的优化

用响应曲面法对液芯包囊乳酸菌连续接种牛奶工艺进行优化。结果表明，发酵温度、pH值对牛奶稀释有显著影响，而搅拌速度的影响不显著。在质量浓度为150g／L液芯胶囊的发酵罐中，发酵温度为39℃，pH值为6．3，搅拌速度为150r／min时，对牛奶进行连续接种，获得每小时8．2的稀释率。     

纯菌接种发酵技术在腌渍蔬菜加工上的应用研究(一) 优良乳酸发酵菌种特性的研究及菌种筛选

应用纯接种乳酸发酵技术生产泡菜是对传统自然发酵模式的一种变革，也是发酵技术现代化的一种标志。本文就影响发酵质量及成败的首要因素－所收集之不同乳酸发酵菌种的生长及发酵特性进行了系统比较和研究，并在此基础上筛选并确定了最适的乳酸发酵菌种及其组合供扩大试验及生产之用。     

通过加增碳剂方法生产HT250铸铁

为降低生产成本,稳定生产HT250材质的机床铸件,采用了一种不经孕育处理的生产工艺.通过调整碳量、控制铁液的化学成分,将碳含量控制在3％～3.6％之间,提高铁液温度及保温时间,过热温度在1 450℃以上时,保温时间控制在15 min以内,可以保证试样抗拉强度在250 MPa以上.经生产验证,不经孕育处理的HT250材质铸铁的铸造性能及加工性能都很好,完全满足技术要求,且降低了成本.     

Analysis of disclosure avoidance procedures

In the collection of data on environmental health, individuals are frequently reluctant to be entirely candid with surveyors because of concern over the confidentiality of responses. A standard procedure is to inoculate the response with random modification (or error) so that it becomes impossible to identify individual respondents but quite possible to generate unbiased statistical summaries of the entire sample. This paper is directed at generating methods for such random inoculation and abstracting from the inoculated results those conclusions concerning sample response and population estimates. A numerical example of a bivariate randomized procedure is given.     

黄金行业特征废水中BOD测定影响因素的分析

黄金行业特征废水通常含重金属、氰化物及硫氰酸盐,且具有强碱性,研究好氧自养型微生物、无机盐、溶解氧含量、接种液背景BOD值及废水性质等5个因素对BOD测定结果的影响。研究结果表明,黄金行业特征废水BOD测定需添加丙烯基硫脲抑制硝化细菌,加入微生物生命活动所需的无机盐,保证水样中溶解氧含量饱和或接近饱和,接种液背景BOD值低,选择耐氰耐重金属的微生物进行接种或根据废水性质对接种液中微生物进行驯化后接种,满足以上条件才能保证BOD测定结果准确。