线切割电参数的合理选择

分析了线切割参数对线切割加工工艺指标的影响,指明了怎样合理选择切割线参数。     

正方介质柱二维光子晶体传输特性FDTD数值研究

把时域有限差分方法用于二维正方介质柱组成光子晶体传输函数理论研究,计算了若干情况下二维光子晶体的透射率即光传输函数随频率的变化。计算结果表明:对于一定的入射方向,某些频率的光不能在光子晶体中传播即出现所谓的禁带,禁带的宽度、频率范围与晶格结构、柱体截面大小及放置方位有关。     

EBF网络特征映射和恢复及其在鲁棒话者识别中的应用

The performance of speaker verification systems is often compromised under real-world environments. For example, variations in handset characteristics could cause severe performance degradation. This paper presents a novel method to overcome this problem by using a non-linear handset mapper. Under this method, a mapper is constructed by training an elliptical basis function network using distorted speech features as inputs and the corresponding clean features as the desired outputs. During feature recuperation, clean features are recovered by feeding the distorted features to the feature mapper. The recovered features are then presented to a speaker model as if they were derived from clean speech. Experimental evaluations based on 258 speakers of the TIMIT and NTIMIT corpuses suggest that the feature mappers improve the verification performance remarkably.     

5-溴水杨醛甘氨酸修饰碳糊电极测定微量Cu2+的研究

在pH=9.0 H3BO3-Na2B4O7缓冲体系中,以5-溴水杨醛甘氨酸修饰碳糊电极为工作电极,Cu2 于 120mV(vs.SCE)处产生一灵敏的吸附波,其二阶导数峰电流与Cu2 浓度在4.0×10-9~8.0×10-7mol.dm-3范围内呈良好的线性关系,相关系数为0.9964,检出限为6.0×10-10mol.dm-3(3倍信噪比)。应用该法测定发样中Cu2 的含量,结果令人满意。     

再论高等职业教育是一种类型

本文从世界高等教育发展史、我国高等职业教育发展史和我国学位制度的演变说明高等职业教育是一种类型,并对今后我国职业教育的发展从认识上、制度上、具体办学上相应提出了建议。     

Pre-service and In-service Secondary School Teachers’ Knowledge about Attention-deficit Hyperactivity Disorder (ADHD) and Attitudes toward Students with ADHD

This article reports on a mixed-method inquiry into pre-service and in-service secondary school teachers’ knowledge about Attention-deficit Hyperactivity Disorder (ADHD) and attitudes toward students with this disorder in Hong Kong. The inquiry revealed no differences between pre-service and in-service secondary school teachers concerning their knowledge of ADHD and attitudes toward students with ADHD. It also identified possible sources of participants’ knowledge and a variety of factors underlying their attitudes toward students with ADHD including sociocultural beliefs and working conditions. The findings call for teacher educators to develop better education programmes to support both pre-service and in-service teachers in undertaking the challenging task of teaching students with ADHD.     

微波辐射合成3-氨基-1,2,4-三氮唑

在微波辐射条件下,以氨基胍重碳酸盐和甲酸为原料合成了3-氨基-1,2,4-三氮唑,反应速度比传统加热条件提高300倍,产率达到83.5%。优化后的最佳反应条件为微波输出功率为120 W,氨基胍重碳酸盐:甲酸摩尔比为1:1.25,溶剂无水乙醇为5mL,反应时间为60 s。     

层析Al2O3循环利用方案

对用于柱色谱分离的填充材料Al2O3，采用清洗、过筛、调节pH值、净化、干燥和活化处理，对获得的Al2O3进行物理性状测试和柱色谱性能研究。结果发现经过煅烧和微波辐射的Al2O3物理性状符合实验要求，对靛酚和甲基橙分离性能良好，两者之间的比移值Rf范围在8．6～9．3，可以采用该工艺对Al2O3进行循环利用。     

镍-磷-氧化铁纳米复合材料镀层的制备及其性能研究

采用复合化学镀方法制备了镍-磷-氧化铁纳米复合材料镀层。通过孔隙率、耐腐蚀性、硬度、耐磨性等性质试验,结果表明:纳米复合镀层致密性、耐腐蚀性和耐磨性等均优于A3钢片,甚至优于Ni-P镀层。     

Starting and Sustaining an Undergraduate Research Program: The SURIEM Experience at Michigan State University

Abstract

Mentoring undergraduate students in research is both rewarding and challenging. In this paper we present how we established a summer Research Experience for Undergraduates (REU) program in the mathematical sciences at Michigan State University. A goal of our REU is to include students who are at an early stage of their study of mathematics. We share our experiences in recruiting students, designing research projects, and mentoring our participants. We discuss the challenges we faced and the solutions we found while working with a diverse group of undergraduate students from across the nation.