Enhancing Learners’Performance in Grade 7 Mathematics Through 50-30-20 Exercise

Assessment exercises constitute a crucial component of the teaching and learning process,serving the purpose of gauging the degree to which learning objectives have been accomplished.This study aims to assess the mathematics performance of Grade 7 learners using the 50-30-20 exercise.Specifically,this study seeks to determine the learners’pre-test and post-test mean scores,identify significant differences between the pre-test and post-test results,evaluate learners’exercises,and propose enhanced exercises.The research employs a quasi-experimental design,with 40 Grade 7 learners in the school year 2023-2024 as participants,selected through purposive non-random sampling.Statistical data analysis involves the use of mean,standard deviation,paired t-test,and Cohen’s D effect size.Ethical considerations were paramount,as evidenced by a letter of authorization from the school head outlining the strict adherence to voluntary participation,informed parental consent,anonymity,confidentiality,risk mitigation,results-sharing protocols,and the commitment to keeping research data confidential.The data yielded a remarkable outcome:the experimental group exhibited improvement in both the pre-test and post-test.This result substantiates the initial objective of the study,showcasing a noteworthy and favorable performance among the participants.Consequently,it suggests that a majority of the participants strongly agree that the 50-30-20 exercises contribute to enhancing their understanding and problem-solving skills,as well as their ability to grasp mathematical concepts and improve their overall performance in mathematics.Therefore,the 50-30-20 exercises not only facilitated students in understanding mathematics lessons but were also aligned with the Department of Education’s development plan.

微量硼和铌对铸造Ni_(50)Al_(20)Fe_(30)合金组织及性能的影响

研究了微量硼和 2 % Nb对铸造 Ni5 0 Al2 0 Fe30 合金组织及性能的影响。结果表明 :微量硼的加入可以改善 Ni5 0 Al2 0 Fe30 合金的强度与塑性 ,最佳硼含量为 0 .0 2 %～ 0 .0 5 % ;此外 ,微量硼的加入影响该合金的共晶区 ,从而明显改变合金的微观组织形态。在硼含量为 0 .0 2 %时 ,该合金主要处于 β相 (Ni Al)与 γ相的共晶区 ,这对合金的室温塑性极为有利。添加 2 % Nb可明显提高该合金的压缩屈服强度并改善塑性。在室温、6 5 0℃和 10 0 0℃ ,该合金的压缩屈服强度分别提高 30 %、5 9%和 36 %

高压处理对Ni_（50）Al_（30）Fe_（20）金属间化合物合金的影响

对Ｎｉ_（５０）Ａｌ_（３０）Ｆｅ_（２０）金属间化合物合金进行１～４ＧＰａ高压处理，发现随着处理压强增高，塑性应变量下降，由于在高压处理条件下样品滑移变形受周围叶蜡石挤压而受到抑制，微裂纹在晶内形核，测试时裂纹容易连通提前产生断裂，其断裂方向由铸态时与压缩轴成４５°，逐渐转变为在高压处理时断面与压缩轴垂直。

Ni_（20）Ti_（50）C_（30）机械合金化过程中的爆炸反应

机械合金化Ｎｉ_（２０）Ｔｉ_（５０）Ｃ_（３０）粉末发生了爆炸式反应，反应产物中粉末和块状样品共存，经Ｘ射线衍射分析和扫描电镜观察表明反应过程中存在部分熔化．产物组成主要为ＴｉＣ和Ｎｉ－Ｔｉ金属间化合物．作者认为球磨过程中球与球的猛烈撞击引发了初始ＴｉＣ的形成，其巨大的生成热诱发了后续反应．

NiAl－Fe金属间化合物合金的正电子寿命谱

测量了塑性金属间化合物合金Ｎｉ（５０）Ａｌ（３０）Ｆｅ（２０），Ｎｉ（５０）Ａｌ（２０）Ｆｅ（３０）和Ｎｉ（６０）Ａｌ（２０）Ｆｅ（２０）单晶和多晶的正电子寿命谱．基于正电子寿命谱的特征参数引入了正电子双区域捕获模型，并讨论了这些合金微观结构与力学性能之间的关系．

医用形状记忆合金电子结构及相稳定性

为获得更适合人体、优异、稳定性好的形状记忆合金材料,通过基于密度泛函理论第一性原理赝势法对NiTi及Ni_(30)Ti_(50)Cu_(20)形状记忆合金的电子结构和相稳定性能进行理论模拟计算,并用力学试验机测试NiTi形状记忆合金样品的力学性能。计算所得的弹性常数和试验测试结果较一致,同时对掺杂20%(质量分数)Cu元素的Ni_(30)Ti_(50)Cu_(20)进行计算和分析,发现掺杂Cu元素后NiTi形状记忆合金的B19相稳定性得到明显的改善,物理性能更稳定。研究结果为NiTi形状记忆合金更安全、更有效的应用于临床矫形外科提供了理论依据。