气相色谱法确定蓝色圆珠笔油墨字迹的形成时间

选择适当的内标物,利用气相色谱法测定蓝色圆珠笔油墨中展色剂苯甲醇和苯氧基乙醇这两种组分的含量(以峰面积计),以展色剂的峰面积、内标物的峰面积与紫外-可见光谱测得的参比物墨水中的染料的吸光度值这三者之比为纵坐标,以字迹形成时间为横坐标,确定了字迹形成曲线,从而建立了确定字迹形成时间的方法。选择了不同种类的蓝色圆珠笔油墨进行检测,获得了良好的实验效果,为圆珠笔油墨字迹形成时间的推断建立了一种可靠而又系统的方法。该方法适用于实际办案。     

我国配位化学的开拓者和奠基人 ——戴安邦先生

戴安邦先生(1901-1999)是我国著名的无机化学家,化学教育家,配位化学的开拓者和奠基人。他一生长达70年之久为我国培养无数高质量科教人才,在教学上提出“启发式八则”和“全面教育理论”,影响深远。他在国内开拓配位化学研究领域,建立配位化学研究所和配位化学国家重点实验室,大力促进国内外学术交流,培养了众多学术人才,使我国配位化学和无机化学在国际上占有重要地位。他提倡“基础理论应为科学发展服务,为应用研究储备资料和积累力量”。“解决实际问题推动科学发展”是他的科研思想。“崇实,贵确,求真,创新和存疑”是一个科学工作者应具有的高尚品德。他身体力行,不辞劳苦,从实际中找课题,在科研和教书育人方面贡献了一生。他的品德高尚,为后人作出了榜样。为表彰其功绩,被国家授予奖项约20余项。并获得江苏省劳动模范称号。     

裂解气相色谱法分析蓝色中性笔字迹的书写墨水种类及墨迹随书写时间的变化规律

中性笔是当前比较流行的一种书写工具,其墨水多采用颜料作为色料成分,很难用水和有机溶剂进行提取,故无法利用分析圆珠笔油墨和水性笔墨水所采用的气相色谱或高效液相色谱等方法进行检验。目前在法庭科学领域内还没有一种有效的方法用于分析中性笔字迹的书写墨水。采用裂解气相色谱法分析了蓝色中性笔字迹的书写墨水,根据色谱峰的个数和保留时间将收集的65个样品分成3类,其中大部分样品属于具有铜酞菁颜料主要色谱峰的第二大类。色谱峰的保留时间和峰面积比值的分析结果表明所建立的分析方法重现性好且稳定。在此基础上,对蓝色中性笔墨迹随书写时间的变化规律进行了初步研究,得出了老化曲线。     

Surface characteristics of SiO2-TiO2 strip fabricated by laser direct writing

SiO2-TiO2 sol-gel films axe deposited on SiO2/Si by dip-coating technique.The SiO2-TiO2 strips are fabricated by laser direct writing using an ytterbium fiber laser and followed by chemical etching.Surface structures,morphologies and roughness of the films and strips are characterized.The experimental results demonstrate that the SiO2-TiO2 sol-gel film is loose in structure and a shrinkage concave groove forms if the film is irradiated by laser beam.The surface roughness of both non-irradiated and laser irradiated areas increases with the chemical etching time.But the roughness of laser irradiated area increases more than thalt of non-irradiated area under the same etching time.After being etched for 28 s,the surface roughness value of the laser irradiated area increases from 0.3 nm to 3.1 nm.     

转镜式高速相机扫描速度检测装置及不确定度评定

基于光电转换基本原理，设计并研制了用于转镜式高速扫描相机扫描速度的检测装置，包括均匀脉冲光源、精密双狭缝、超快响应光电转换器以及高带宽、高采样率数字示波器等。论述了检测装置的核心部件，用该装置实测了SJZ-15型转镜扫描相机名义扫速为4．5mm／μs的扫描速度，计算出了扫速不均匀性。按照国军标GJB3756，对检测装置的测量不确定度来源进行了分析，给出了该装置的不确定度评定方法及测量不确定度，对检测结果的评定表明，该检测装置的相对测量不确定度不大于0．1%，远低于目前转镜扫描相机的最大扫速不均匀性水平。实验证明，设计的检测装置具有很高的准确度和可靠性。     

关于高等数学中极限思想的研究

本文针对在工科高等数学的教学中 ,学生对极限这一重要概念难以把握和理解的现象 ,提出了分三个层次并从哲学的角度来理解这一思想 ,为学生最终解决这一难点提供了一种有效的方法 .     

转镜扫描相机记录象面的新设计理论

由于加工高次曲线已有可能,用代替圆来拟合超越曲线已无必要.本文提出转镜扫描记录象面的新设计理论和方法,能得到理想的记录象面;无离焦记录象面,等速扫描记录象面和离焦、扫描速度的不均匀性都最小的记录象面.     

强化物理思想,展现物理学之美——首届全国高等学校物理基础课程青年教师讲课比赛心得

2014年夏有幸参加了首届＂高等教育杯＂全国高等学校物理基础课程青年教师讲课比赛决赛,并取得了第一名的成绩.比赛结束后,我认真思考这么多年的教学历程,有了一些心得体会,拿来与大家共享.我认为基础物理教学青年教师的成长离不开优秀团队的支持,必须多方面汲取营养以开拓自己的视野;而基础物理教学内容则必须强调物理思想淡化数学计算,认识物理学之美培养学生物理思维.     

Low cost fabrication of SiO2 optical waveguides by laser direct writing on Ti-doped Sol-Gel films

A commercial direct laser writing (DLW) system operating at 1070 nm was used to fabricate SiO₂ optical waveguides on silicon wafers. A Ti-doped SiO₂ Sol-Gel film was deposited on the SiO₂/Si substrate by the dip-coating technique, based on which SiO₂ optical waveguides were patterned by DLW using a Ytterbium fiber laser and followed by chemical etching. The effects of laser parameters and the preheated temperature of Sol-Gel films on the dimensions of optical waveguides were studied systematically. The differences of etching rate between laser irradiated and non-irradiated areas in Sol-Gel films preheated at various temperatures are characterized by measuring the thickness of the films. Results demonstrate that the available laser power density range for laser densification and the width of the patterned optical waveguides are influenced strongly by the preheated temperature of the Sol-Gel films. The width of the optimized optical waveguide in this work is 25 μm. The minimum propagation loss of the fabricated optical waveguides is 1.7 dB cm⁻¹ at the wavelength of 1550 nm.     

An analysis of the amount and characteristics of writing prompts in Grade 3 mathematics student books

Curriculum guidelines and professional organizations’ recommendations lack details about how often and how much students should write in mathematics and what characteristics should define their writing. This study presents an analytic framework that addresses how often students are prompted in student mathematics books to write, how much they may be encouraged to write, and the characteristics of the writing prompts. Consequently, 2,095 writing prompts in student books across 10 comprehensive Grade 3 resources were analyzed. Findings indicate a marked variation in how often and how much students are positioned to write. Most prompts have students explain what they did to solve a problem and why about number concepts, with most pressing for procedures. The greatest percentage of prompts had students write about their own solutions and do not urge them to include specific writing features.