Al2O3-MgO系无碳钢包衬浇注料的研究

研究了尖晶石或镁砂的加入量和粒度对Al2O3-MgO系无碳钢包衬浇注料的抗渣性能和高温体积稳定性的影响。研究表明:刚玉-尖晶石质浇注料尖晶石的较佳加入方式是细颗粒和微粉组合形式加入;刚玉-方镁石质浇注料中镁砂加入量以3.5~5.0%为适。     

红柱石对水泥结合电炉盖浇注料性能的影响

为解决电炉盖浇注料强度低、热震稳定性差等问题,以莫来石、红柱石、刚玉、硅微粉为主要原料,通过调整添加剂(红柱石、蓝晶石)的种类及水泥加入量,优化了电炉盖浇注料的组成及性能。通过分析热震实验后浇注料的强度保持率,对提高热震稳定性的原因进行了探讨;随着水泥加入量的增加,浇注料的抗折强度先增加后逐渐降低,而热震稳定性在合适的用量范围内也有改善;采用红柱石制备的浇注料具有更高的致密度及力学强度。     

对机械能守恒定律两种表述的理解

关于机械能守恒定律在现行高一新教材中的表述是:在只有重力做功的情形下,物体的动能和重力势能发生相互转化,但机械能的总量保持不变.而在旧教材(必修)中的表述是:如果没有摩擦和介质阻力,物体只发生动能和势能的相互转化时,机械能的总量保持不变.笔者认为这是两守恒条件的两种不同侧重的理解:     

对机械能守恒定律两种表述的理解

关于机械能守恒定律在现行高一新教材中的表述是:在只有重力做功的情形下,物体的动能和重力势能发生相互转化,但机械能的总量保持不变。而在旧教材(必修)中的表述是:如果没有摩擦和介质阻力,物体只发生动能和势能的相互转化时,机械能的总量保持不变。笔者认为这是两守恒条件的两种不同侧重的理解:     

吸附罐摇摆对13X-HP分子筛吸附性能的影响

针对海上天然气开采时吸附罐随海浪的波动而产生的摇摆问题,以13XHP分子筛为吸附剂,利用摇摆平台吸附高纯CO_2,考察吸附罐在静止和摇摆状态下吸附剂对CO_2的吸附性能。结果表明:13X-HP分子筛吸附高纯CO_2是单分子层吸附,吸附等温线属于I型,能够用Langmuir等温式对实验数据进行拟合;摇摆会提升吸附剂的吸附量,存在一个最佳的摇摆频率使吸附剂的吸附量最大;吸附过程中所放出的吸附热与吸附量的变化是一一对应的,随着吸附过程的进行,吸附罐内所达到的最高温度逐渐降低;吸附罐中间层的吸附主要发生在内部,随着吸附质向下运动,底端的吸附位置较中间层范围更广。     

对机械能守恒定律两种表述的理解

机械能守恒定律在中学物理高一新教材中的表述是 :在只有重力做功的情形下 ,物体的动能和重力势能发生相互转化 ,但机械能的总量保持不变 .而在旧教材中的表述是 :如果没有摩擦和介质阻力 ,物体只发生动能和势能的相互转化时 ,机械能的总量保持不变 .笔者认为这是侧重于守恒条件的两种不同理解 .1 .从功和能的关系理解由功能原理 Σ W外 + Σ W非内 =ΔE可知 ,一切外力所做的功 Σ W外 和一切非保守内力所做的功 Σ W非内 的代数和为零时 ,系统机械能的增量等于零 .从功能关系的角度看 ,重力 (弹簧的弹力 )做功不会改变物体的机械能 ,除重…     

“П”字型知识结构——信息社会对教师的诉求

知识结构由个体知识结构和群体知识结构之分,在这里,我们只谈个体知识结构。所谓个体知识结构,是指某人所具有的各种知识的质与量的对比关系。所谓质的对比关系,是指该人具有几种不同方面或领域(专业)的知识及其之间的相互关系,质的对比关系表明了该人知识面的宽度;而量的对比关系表明该人所具有的各种知识深度。如果这种质的对比关系和量的对比关系组成合理,我们便说这个人具有合理的知识结构。一、个体知识结构的类型从个体知识结构中知识的质与量两个之间的关系来分析,我们可以得到两种典型的个体知识结构类型:“—”字型知识结构和“T…     

结合剂对钢包衬砖性能的影响

研究了三种不同的结合剂对钢包砖性能的影响.实验表明:树脂结合的机压钢包砖碳含量在1%左右,而无机结合剂F50和E08不会向钢包砖引入另外的碳,适应了钢包无碳化发展趋势.无机结合剂F50在铝镁质钢包砖上使用,提高了钢包砖的高温强度,同时不影响铝镁质钢包砖的抗渣性和热震稳定性.无机结合剂E08在镁铝质钢包砖上使用,不影响镁铝镁质钢包砖的抗渣性和热震稳定性.     

《解决问题的策略》教学设计

教学内容 苏教版小学数学六年级上册第89—90页。 设计理念 “解决问题的策略（替换）”其实质是中学阶段学习的二元一次方程,通过替换把两种量与总量之间的复杂数量关系转化为一种量与总量之间的简单数量关系。教学实践表明用“算术”思维来理解倍比关系、差比关系两种不同类型的替换,会给学生一种多变、难以把握的感觉,缺少一个统领思维的不变的核心。而用“代数”思维来解决问题,图式结合,以已知的等量关系为基准,在维系等式的平衡中体会变与不变的内涵,这样处理更易于学生掌握。     

对比分析以英语为母语和以英语为外语的两个聊天室的词汇

计算机协调话语分析随着网络的开发与深入工作、生活而日益受到语言学家的关注。本文采用量的和质的方法，对比分析以英语为母语和以英语为外语的两个网络即时聊天的话语，发现以英语为母语者与以英语为外语者在缩写的数量和种类上有所不同，而且两者在所使用的词汇级别上也不一样，后者更多地使用基础词汇1中的词汇。由此可见，外语学习者要想通过网络聊天来促进外语习得，应当更多地加入以英语为母语的聊天室。     

菱镁矿生产轻质氧化镁除杂(铁、铝)工艺的研究

在不同酸度条件下对菱镁矿去除Fe3 、Al3 离子后获得的产物进行了研究,测定了除杂后获得的轻质氧化镁的纯度和产率,对比得出了较适宜的工艺条件,在PH=8～9时,溶液除杂效果最为显著,MgO的纯度为99.05%,产率为44.32%.     

添加微量稀土对提高电工用铜母线性能的作用

在纯铜熔体中以 Al-RE 中间合金形式加入富 Ce 混合稀土,探讨了 RE 加入量对电工用铜母线铸态组织、力学性能和导电性的影响规律.结果表明:纯铜基体的纯净度随RE加入量的增加而明显提高,当w(RE)=0.02%时,结晶组织最为细小,力学性能得到改善;添加RE可显著改善纯铜的导电性,其影响作用取决于稀土化合物的分布状态及基体的纯净度,当w(RE)》0.02%后,导电率略为降低.当w(RE)=0.05%,可使纯铜获得较理想的综合性能,基本满足高强高韧高导铜母线的生产要求.     

氧化铝陶瓷凝胶注模成型中料浆流变性研究

对氧化铝悬浮液的分散效果和流变性进行了研究,通过调节悬浮液的pH值和加入分散剂来获得沉降量最少、分散效果最好的悬浮液。实验表明:pH值、分散剂用量均会明显的影响悬浮液的分散效果和流变性,当pH=9,分散剂用量为0.5%(质量比)时分散效果最好。同时也研究了固相含量对悬浮液流变性的影响,并制备了固相含量达53%(体积比)的浓悬浮液,能满足凝胶注模成型的要求。     

复合改性剂改善菱镁制品性能的实验研究

采用加入微硅粉和乳白胶及水玻璃等构成的复合改性剂,通过实验找出复合改性剂的最佳配方。高分子聚合物包覆在晶体外壁形成良好的防水保护层,并在晶体间的空隙中自行交联堵塞毛细孔道,硅酸根能与Mg2+形成抗水性较强的胶凝结晶化合物,使菱镁制品返卤泛霜的现象得到了明显的抑制,制品强度进一步增加。     

r—PET改性技术研究进展

通过对r—PET进行改性,可以达到改善材料性能的目的,这不但可以减少环境污染,而且还可以节省资源。从增黏改性、固相挤出法改性、共混改性、反应改性和增容改性等几个方面论述了聚对苯二甲酸乙二醇酯（肿）瓶回收料改性技术的研究进展。     

Turnover Causation Amongst High School Teachers in Nigeria

Four theoretical frameworks were used to explore causations of turnover amongst high school teachers in Nigeria: (1) teachers’ personal health, (2) work–family life, (3) job satisfaction, and (4) actual turnover intention. Quantitative data were obtained from 925 public high school teachers in Ogun State, South-Western Nigeria. Cronbach's Alpha reliability procedure, regression modelling and t-test were used to analyse a total of 96 causations of turnover. Ad hoc analysis returned an Alpha value of 0.78. However, this improved to 0.93 when the causation factors were reduced to 64 – those with highest item-rest and itemtotal correlations. The findings showed that job (dis)satisfaction, personal health and work– family life conflict are prominent amongst the issues that trigger the intention of Nigerian high school teachers to quit their jobs voluntarily. Insights from the findings will help funding administrators in prioritising strategic decisions around mitigating turnover.     

Crystallization inhibition of an amorphous sucrose system using raffinose

The shelf life of pure amorphous sucrose systems, such as cotton candy, can be very short. Previous studies have shown that amorphous sucrose systems held above the glass transition temperature will collapse and crystallize. One study, however, showed that adding a small percent of another type of sugar, such as trehalose, to sucrose can extend the shelf life of the amorphous system by slowing crystallization. This study explores the hypothesis that raffinose increases the stability of an amorphous sucrose system. Cotton candy at 5 wt% raffinose and 95 wt% sucrose was made and stored at room temperature and three different relative humidities （%RH） 11%RH, 33%RH, and 43%RH. XRD patterns, and glass transition temperatures were obtained to determine the stability as a function of%RH. The data collected showed that raffinose slows sucrose crystallization in a low moisture amorphous state above the glass transition temperature and therefore improves the stability of amorphous sucrose systems.     

Framing the Problem: effects of wording on children's statistical inferences

ABSTRACT A total of 96 children aged 11 to 12 years were given statistical inference problems (base‐rate and law of large numbers) designed to test the effects of wording on their answers. The wording of the problems was manipulated to make the information on base‐rates and on the law of large numbers either more salient or less salient. The latter condition was established by adding extraneous information to base‐rates, or, in the case of the law of large numbers, making the context unfamiliar or focusing choice on a particular person rather than on the group. A significant main effect of wording was found across all problems in favour of the salient condition. The results indicated that the children had a high level of statistical intuition and that they knew when to reason statistically and when not to.     

Trends in child maltreatment in the US Army, 1975-1997.

OBJECTIVE: To examine trends by year in reports of victims of child maltreatment in the US Army Central Registry (ACR) during the period 1975-97. We report the rates/1,000 children of Army families of initial substantiated cases from 1988-97 and the number of cases of maltreatment as a percentage of total victims for each year from 1975-97. Army data are compared to published reports from military service child abuse registries. METHODS: Numbers of cases of child maltreatment for each year were obtained from the ACR for major, minor, and total physical abuse, sexual abuse, emotional abuse, and neglect. Population figures for numbers of children were obtained from the Defense Manpower Data Center. RESULTS: The rates/1,000 for neglect have decreased by 24% from 1991-97, although the decrease has not been steady. The rates/1,000 of minor physical abuse declined 28% from 1993-97. The rates/1,000 of major physical abuse were basically unchanged from 1988-96, although the highest rate was recorded in 1997. The rates/1,000 of sexual abuse were also basically unchanged with the exception of increases in 1992-94 after which time the rates/1,000 returned to the pre-1992 levels. The rates/1,000 of emotional abuse cases more than doubled from 1988-97. CONCLUSIONS: While minor physical abuse and neglect have shown decreases over the past decade, major physical abuse has remained virtually unchanged and sexual and emotional abuse have shown fluctuations. All these forms of maltreatment are challenges to the Army Family Advocacy Program.