太赫兹时域光谱技术

介绍了太赫兹时域光谱技术的优势,太赫兹时域光谱系统及太赫兹时域光谱技术的原理和应用.     

太赫兹时域光谱系统在实验教学中的应用

将太赫兹时域光谱系统应用于本科实验教学,使学生熟悉太赫兹时域光谱系统的使用,提高学生的动手实践能力,激发学生的科研兴趣。通过前沿科研仪器设备与本科实验教学的结合,推动研究型和创新型人才的培养。     

THz-TDS和FTIR对云冈石窟岩芯的光谱分析

分别利用太赫兹时域光谱系统（THz-TDS）和傅里叶变换红外光谱仪（FTIR）,对由钻孔取芯机所取岩芯上选取的6个不同深度样品进行了测试。结果表明：随着样品深度的增加,在太赫兹波段,吸收系数和透射系数变化不明显,但折射率则逐渐降低;在红外波段,样品所含盐类逐渐减少,而CaCO3和SiO2的含量则逐渐增大,说明盐类物质是由外部环境污染而来,内部岩石则尚未被污染。     

云冈石窟石质、降尘样品的太赫兹光谱分析

利用太赫兹时域光谱系统,分析了由云冈石窟所采集的石柱、降尘和新鲜岩石3种样品在THz波段的光谱特征。通过比较分析得出,3种样品在整个波段,均无明显的吸收峰,低频区吸收都很弱,高频区吸收系数以接近指数函数趋势增长,特别是降尘的吸收最大,新鲜岩石的次之,石柱的吸收最弱。在整个波段,石柱的折射率很稳定,基本不发生变化,其余两个样品的折射率则发生波动。     

基于太赫兹时域光谱技术的砂岩沉积作用模拟研究

为模拟地质构造环境,选用石英砂颗粒作为模拟岩石的主要成分,与聚乙烯颗粒按一定比例混合后压片,并进行太赫兹光谱测试。实验发现质量分数为35%聚乙烯65%石英砂样品对太赫兹波的吸收随压力增加而增强,这与压力增大导致样品的密度增加有关,而50%聚乙烯50%石英砂样品对太赫兹波的吸收随压力增加先增强而后减弱,吸收减小与不同成分排列状况改变有关。实验表明,太赫兹光谱信息可以表征通常地质演化过程中随着埋深增加负荷加大而压实作用加强的过程,以及在特定的地质环境中,压实作用加强趋势受阻的过程。     

依托太赫兹技术的探测识别新型作战力量人才培养研究

太赫兹技术是目前信息科学技术研究的前沿与热点领域之一,也是下一代探测识别技术的重要发展方向.世界军事科技变革的持续深化对探测识别新型作战力量人才培养模式提出了新的需求.以依托太赫兹技术的探测识别新型作战力量人才培养为着眼点,梳理国内外新型作战力量人才培养的研究现状和面临的问题,提出人才培养的新思路与新模式,为探测识别新...     

具有参考样品的太赫兹波双路透射测量系统

太赫兹波透射测量技术能够很好地应用于无损检测领域,然而样品在进行透射测量时存在着F-P效应,太赫兹波源功率的波动与频率的漂移都会极大地影响测量结果的精度。文中设计了一种具有参考样品的双路透射测量系统,并模拟比较了传统单路透射测量系统与文中设计的双路透射测量系统两者的测量误差,最后对如何选择参考样品进行了分析。结果证明该测量系统可以有效地克服太赫兹波源功率的波动与频率的漂移,大大提高了测量的精度。     

太赫兹辐射功率密度打孔扫描测量

搭建了太赫兹汇聚测量光路,利用太赫兹探测器直接扫描测量的方式,实现了100 GHz辐射源空间辐射功率密度测量;利用太赫兹探测器包裹打孔锡纸的方法,减小接收孔径,消除探测器测量结果的卷积影响,提高了测量空间分辨率。将两种测量方法进行比较,结果表明:直接扫描法具有较高的信噪比,但空间分辨率低;打孔扫描法具有高空间分辨率,但信噪比较差。该结论可为太赫兹功率计量标定光路系统的设计提供参考。     

首次实现太赫兹示波器记录飞秒相对论电子束完整时间信息的精确测量——上海交大课题组与合作者发表重要成果

<正>上海交通大学物理与天文学院张杰院士和向导教授领导的课题组与华东师范大学、中科院上海光机所、西北核技术研究所等国内外同行合作,研制了一种用于记录超短电子束时间信息的太赫兹示波器。利用两个偏振态方向相互垂直的线偏振太赫兹脉冲合成圆偏振脉冲,首次在介质波导中以太赫兹波长为时间基准实现对相对论能量级电子束完整时间信息的精确测量,用这种太赫兹示波器,相对论电子束的近50倍纵向压缩可直接显     

探究太赫兹科学技术的研究和应用

太赫兹波技术在物理、化学、生命科学等基础研究学科,以及医学成像、安全检查、产品检测、空间通信、武器制导等应用学科都具有重要的研究价值和应用前景.从THz辐射源、THz波的检测及标定、THz波与物质相互作用和THz波的应用四个方面概述了太赫兹科学技术的研究和应用新进展.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

钱生钱!

我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了     

Inequalities for inscribed simplexes

The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

微薄的薪水,高尚的情操

现在,我们可以没有面包,没有钱,没有房子,没有车子……但我们唯独不能丢失的是高尚的情操,笃定的信念,还有,满满的希望!     

Virtual reality approach for 3D large model browsing on web site

Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching.