硅钢DR510生产工艺优化

本文对某厂硅钢DR510温度、成分及过程控制水平和成品的组织、力学性能进行了研究,并在此基础上提出了工艺优化方案,有一定的借鉴和推广价值。     

利用钼尾矿粉替代砂研制混凝土小型空心砌块

根据钼尾矿粉的细度条件,选择与0．63mm以上粒径砂混合,提出了利用钼尾矿粉替代砂生产混凝土小型空心砌块较为合理的替代量。通过正交试验方法进行钼尾矿粉混凝土小型空心砌块母体混凝土的优化配合比设计,研制钼尾矿粉混凝土小型空心砌块。     

纳米SiO_2对氰酸酯树脂/纳米SiO_2复合材料粘度的影响

采用高速均质剪切法制备氰酸酯树脂（CE）/纳米二氧化硅（nano-SiO2）复合材料,通过测试粘度变化,考察了nano-SiO2对复合材料粘度的影响.结果表明：nano-SiO2能够极大提高复合材料的胶粘性;相对于纯CE,3.00%nano-SiO2含量,工作温度90℃时复合材料粘度的相对提高率为67.99%;工作时间8h时复合材料粘度的相对提高率为51.51%.     

拟穴青蟹凝集素的活性及其部分性质

采用生物化学的方法研究了拟穴青蟹凝集素的部分性质,结果表明：拟穴青蟹血清的凝集素可凝集兔子、鸽子、鸭子、鸡的动物血红细胞,并且对不同的红细胞的凝集效价有所不同,该凝集素的活性受D-半乳糖、麦芽糖、鼠李糖等3种糖所抑制.在温度为30～40℃,pH为7.0,盐度为24时,拟穴青蟹血清凝集素活性最高.拟穴青蟹血清样品的凝集素受Ca2＋的依赖性较小.     

含参量广义积分分析性质的证明

通过2个引理给出了含参量广义积分分析性质的另外一种证明方法,即直接计算法,这有助于深刻理解含参量广义积分的分析性质.     

立方氮化铝在一定压强下的电子结构与热力学性质

运用超软赝势平面波第一性原理方法,对立方 AlN 晶体在 0-30GPa 的不同压强下进行了结构几何优化,得到平衡晶格参数;在优化结构的基础上计算了电子结构、弹性常数、体弹模量与德拜温度;结果表明立方氮化铝晶体为间接宽带隙半导体,随着压强的增加,晶格参量减小,弹性常数、体弹模量与德拜温度增加,带隙先增大后减小,在 7GPa 时带隙为 5.117eV,达到最大值．     

柚子皮吸附剂对铅离子吸附性能的研究

为了了解柚子皮对废水中铅离子的吸附性能,利用柚皮制作金属离子吸附剂．对影响吸附性能的吸附剂粒度、投料比、吸附时间、pH值、流动状态等因素进行吸附试验研究。结果表明：当柚皮吸附剂粒度为60目。投料比为0．2g／100mL溶液,pH=7,吸附时间为6h,流速为0．21mL／s时,吸附重金属铅的能力最强,吸附率达到76．54％,其吸附容量为38．27mg／g。     

Why Do Historical Beeswax Seals Become Brittle Over Time?

ABSTRACT

Mechanical properties of aged beeswax were studied by an indirect measurement, using hydrogenated beeswax as a model material. The adequacy of the model was evaluated by comparison of its chemical composition and thermal properties with those of samples of historical beeswax. It was found that the gradual decrease in content of unsaturated compounds in beeswax contributes significantly to changes of its mechanical properties. As a consequence, beeswax artefacts become increasingly prone to mechanical damage during natural ageing. Understanding the difference between mechanical properties of recent and historical beeswax is primarily important from the point of view of safe handling and storage of such artefacts. Besides, this knowledge could help conservation scientists, e. g. when preparing model samples for testing new conservation methods.     

Examining the factor structure of the Family Child Care Environment Rating Scale—Revised

The purpose of this study was to examine the factor structure of the Family Child Care Environment Rating Scale—Revised (FCCERS-R) in high-stakes contexts. The results of an exploratory factor analysis revealed three dimensions of quality on the FCCERS-R: (1) Activities/Materials, (2) Language/Interaction, and (3) Organization. This study also explored whether abridged versions of the FCCERS-R could serve as a proxy for the full instrument. In addition to subsets of FCCERS-R items created from the factor structure, purposively and randomly chosen item subsets were created. The purposively chosen subsets included 6-, 9-, and 12-item scales comprised of the items with the highest factor loading across the three factors, whereas the randomly chosen subsets consisted of 12 items. Results of a discriminant analysis showed that the factor subsets were poorer proxies for the total FCCERS-R score than were the other subsets, which demonstrated comparable internal consistencies and discriminant power as the full FCCERS-R when classifying homes into general quality categories. Implications for adopting shorter versions of the FCCERS-R are discussed.     

Exploring Dominant Types of Explanations Built by General Chemistry Students

The central goal of our study was to explore the nature of the explanations generated by science and engineering majors with basic training in chemistry to account for the colligative properties of solutions. The work was motivated by our broader interest in the characterisation of the dominant types of explanations that science college students use to make sense of phenomena under conditions of limited time and limited explicit knowledge about a topic. Explanations were collected in written form using two different quizzes that students completed under time constraints at the end of a two‐semester general chemistry course. Our study revealed that students’ ability to generate causal/mechanical explanations depended on the nature of the task. In general, students were more inclined or able to generate mechanistic explanations to account for boiling‐point elevation and freezing‐point depression than to make sense of osmotic flow. The analysis of the types of causal explanations built by the study participants suggests that students may be biased towards some causal models or explanatory modes characterised as causal‐additive and causal‐static in our work. A large proportion of the students built non‐causal teleological explanations to account for osmotic flow. None of the participants in our study used a dynamic model of matter as the basis for their explanations of any of the relevant phenomena; the idea of an underlying random process that is taking place at all times giving rise to emergent properties and behaviours was completely absent from their intuitive reasoning under conditions of limited time and knowledge.