基于项目引领的《模具制造与装调》课程教学改革实践     

陈刚  刘新灵 《佳木斯教育学院学报》2014,(12):2-3

传统的高职模具教学将理、实分开,重模具专业理论知识,轻模具实训技能的掌握,实质上不是高等职业教育的初衷。在这样的情形下,对《模具制造与装调》课程教学模式进行了改革,采用项目引领的教学模式,将企业典型零件融入教学,在"做中学"、"学中做"的教学改革中取得了较好效果。  相似文献   

基于C8051F020的智能红外报警系统设计     

熊杰 《黄冈师范学院学报》2014,(3):47-49

以C8051f020单片机作为控制核心,采用热释电红外传感器模块DYP-ME003作为前端探测器,通过SPI协议模式对语音芯片ISD1700进行语音录放功能的精确操控,实现语音门铃录音、播放,报警声录音、播放等。若有人入侵,则通过单片机控制GSM模块按照设置好的号码及信息发送到主人的手机上,达到报警目的。测试结果表明,该系统能真实再现语音效果,运行稳定、可靠。  相似文献   

急性铅中毒对小鼠睾丸病理损伤研究     

孙相和  孔令芸  李冲  陈玲丽  宁红梅  葛亚明 《河南职业技术师范学院学报》2014,(4):49-51

为了研究急性铅中毒对小鼠睾丸病理变化的影响,通过对小鼠饲喂含有醋酸铅的去离子水建立铅负荷小鼠模型.处理10 d后取材,分析体质量、睾丸指数和睾丸病理剖检变化.结果显示：与对照组相比,铅中毒组小鼠体质量无明显变化,睾丸指数降低,且差异显著（P＜0.05）;小鼠睾丸中支持细胞、生精细胞和间质细胞数量减少.铅对小鼠睾丸具有显著损害作用,从而影响小鼠的生殖健康.  相似文献   

公共管理类课程案例教学的探索与实践--以内蒙古师范大学为例     

王永明  杨一江  甘月文  丁彩霞  程萍 《内蒙古师范大学学报(哲学社会科学版)》2014,(2):129-131

案例教学法改变了传统“填鸭式”教学灌输式、封闭式、学生被动地接受知识、缺乏体验与反思的状况,使学生从被动学习转变为积极主动参与课堂教学,在体验中提升能力、掌握知识。案例教学法精髓主要表现为变被动式学习为主动式学习、“集中轰炸式”培训、“唯一”不受欢迎、案例教学是成本最低的“社会实践”。在探索过程中呈现出来“三个一”教学法、“体验、讨论参与、分享式”课堂教学方法等独具创新的方法,在公共管理类课程教学实践中取得了良好的效果。  相似文献   

Light-induced color changes and chemical modification of treated and untreated chestnut wood surface     

none 《文物保护研究》2013,58(2):131-139

Abstract

The aim of this work is to study the surface modifications of chestnut (Castanea sativa Mill.) wood by reflectance spectrophotometry and Fourier transform infrared spectroscopy (FTIR) in order to understand the mechanisms that cause changes and to suggest possible solutions to avoid degradation phenomena. The experimental data were statistically treated to evaluate their significance. Concerning the surface protection of wood, starting from the results obtained by testing different commercial products, attention was focused on a novel organic preservative/consolidant product (Linfoil^®) that has attracted great interest in the field of conservation of wooden artifacts. Color monitoring showed that wood surface color undergoes an important variation due to photoirradiation, occurring within the first 24 hours and mainly due to L* decrease and b* increase. Though the protective treatment modifies wood color, nevertheless the product tested seems to protect the wood surface by reducing photoyellowing. FTIR analysis indicated that irradiation caused the degradation of lignin and increased the concentration of the chromophore groups on the wood surface. Changes in the chromaticity coordinates can be linked to the degradation of lignin and to increase of the concentration of carbonyl groups.  相似文献   

第三液相富集——石墨炉原子吸收光谱法分析巨大口蘑中的痕量铅     

李涛  王元忠 《玉溪师范学院学报》2008,24(8):20-24

系统优化了二安替比林甲烷(DAM)·氢碘酸(HI)三相体系中第三液相对铅的富集条件,使得第三液相对铅有很高的富集倍数和很好的选择性,并采用直接进样技术首次与石墨炉原子吸收技术联用,建立"二安替比林甲烷·氢碘酸第三液相富集一石墨炉原子吸收法测定巨大口蘑中铅"的新方法.用该方法分析巨大口蘑中的铅,方法检出限为(0.500 0g试样)0.090 μg/g,相对标准偏差不超过9%.  相似文献   

一类供应链中订货批量对订货提前期的影响研究     

杨卫平 《软科学》2008,22(9)

研究了由多个采购商到一个制造商采购同种物品而形成的网状供应链中,订货批量对订货提前期的影响。通过对理论和企业实践两方面分析,结果表明,订货批量和订货提前期正相关;订货提前期会随订货批量同向变化;订货批量在高位时的变化所产生的订货提前期的变化比在低位时产生的订货提前期的变化大。可以通过订货小批量化缩短订货提前期。  相似文献   

环戊基甲基酮连氮的合成及表征     

赵鹏  赵文昭  夏洋峰  刘龙  张延强 《中国科学院大学学报》2021,38(5):583-589

以环戊基甲基酮和水合肼为原料,合成一种新的酮连氮化合物(环戊基甲基酮连氮,C14N2H24),采用1H NMR、13C NMR和IR表征确认产物的结构,并通过Gaussian 09计算对产物分子构型进行解析,表明(1E,2E)为最稳定构型;同时测定环戊基甲基酮连氮在常压下的基本物理化学性质,包括沸点(Tb,238.4℃...  相似文献   

中国铅资源流动及其循环效率     

李新  康欣宇  林靖  陈璐  王敏晰 《资源科学》2021,43(3):535-545

中国是全球最大的精铅生产国和消费国,铅资源对外依存度一直保持在20％左右,而铅在全生命周期的损失带来的环境影响严重地危害了人类生命健康.本文定量分析了中国铅元素的流量、社会存量、理论报废量、回收量和循环效率等指标,得到中国铅资源在其全生命周期各个阶段的投入产出量、损失量和循环效率等情况,从而为中国铅资源高效循环利用和减...  相似文献   

FTIR Measurement of Cellulose Microfibril Angle in Historic Scots Pine Wood and Its Use to Detect Fungal Decay     

Kate Hudson-McAulay  David Auty 《文物保护研究》2018,63(6):375-382

Microfibril angle (MFA) – the orientation of cellulose fibres in the S2 layer of the secondary cell wall – is a key determinant of the stiffness and strength of timber. The microfibril angle depends on the way in which the timber was grown and its position within the tree. Microfibril angle can be measured by X-ray diffraction and other methods, but the methods in current use are slow or require advanced instrumentation. The aim of this study was to explore the use of polarised Fourier transform infrared (FTIR) microscopy as a relatively fast and inexpensive method for measuring MFA in historic Scots pine (Pinus sylvestris L.). The FTIR measurements were calibrated against X-ray measurements of MFA in modern Scots pine. We observed a wide range in MFA values and a radial pattern of MFA similar to modern Scots pine in undecayed Scots pine heartwood from sixteenth and seventeenth century beams in Scottish secular buildings. The density of the heartwood was also similar to modern plantation-grown Scots pine despite the much slower growth rate recorded in the ring widths of the historic timber. The sapwood, which had been attacked by both insect pests and fungi, showed an erratic reduction in density and a large increase in MFA compared to the modern material. The increased sapwood MFA was attributed to selective destruction of the S2 layer of the wood cell walls by fungal decay. Using MFA measurements in conjunction with density offers the possibility to estimate the mechanical properties of sound historic pine timber, to detect fungal decay more sensitively than by density alone, and to distinguish between pest and fungal attack in a way that relates directly to the remaining mechanical performance of the timber.  相似文献