Dynamic readout of subdiffraction-limited pit arrays with a silver superlens

Recent theoretical and experimental results suggested that the silver superlens could be constructed through controlling silver thin film thickness and preparation conditions, and applied in subdiffraction-limited optical imaging and optical lithography. In this work, we report another significant application of silver superlens-ultrahigh density optical data storage. With the silver superlens the subdiffraction-limited pit arrays on an optical disk are dynamically read out and the carrier-to-noise ratio can reach 25 dB for the thin film thickness of 46 nm. The readout laser power and readout velocity have little effect on the carrier-to-noise ratio. Additionally, in our experiment the silver thin film thickness needs to be controlled in the range from 20 to 80 nm.

On the dynamic readout of sub-diffraction-limit pit arrays with a silver thin film

Fast moving arrays of periodic sub-diffraction-limit pits were dynamically read out via a silver thin film. The mechanism of the dynamic readout is analysed and discussed in detail, both experimentally and theoretically. The analysis and experiment show that, in the course of readout, surface plasmons can be excited at the silver/air interface by the focused laser beam and amplified by the silver thin film. The surface plasmons are transmitted into the substrate/silver interface with a large enhancement. The surface waves at the substrate/silver interface are scattered by the sinusoidal pits of sub-diffraction-limit size. The scattered waves are collected by a converging lens and guided into the detector for the readout.

CpG islands or CpG clusters: how to identify functional GC-rich regions in a genome?

Background: CpG islands (CGIs), clusters of CpG dinucleotides in GC-rich regions, are often located in the 5' end of genes and considered gene markers. Hackenberg et al. ( 2006) recently developed a new algorithm, CpGcluster, which uses a completely diffe

人类基因同义密码子偏好的特征以及与基因GC含量的关系

对人类的728个基因，按其编码区中GC的含量分成四组（从GC < 0.43到GC > 0.58），分别考察了这四组样本对同义密码子偏好的特征，发现在全部样本中都呈现NTG（N代表四种碱其中的任一种）特爱偏爱和NCG尽量避免的特征。基因环境中GC含量与C3／G3含量（密码子第三位C和G的含量）的相关分析，以及四组本对密码子的偏好都支持以C线的密码子在编码中有特殊的优势，这种优势有利于保证翻译的准确性。还考察了各种氨基酸含量随编码区GC含量不同而变化的趋势。

The features of synonymous codon bias and GC-content relationship in human genes

728 human genes were divided to four groups according to the GC contents of their coding sequences (from GC<0.43 to GC>0.58). Examination of synonymous-codon bias in the 4 groups show that NTG (N represents any base of T, A, C, G) is most favored and NCG

利用HS-SPME-GC技术分析环境水样中超痕量的六氯苯,DDT及其代谢产物

利用顶空固相微萃取(HSSPME)和气相色谱检测技术,通过对三种不同的SPME萃取头(PDMS,PMPVS,PA)实验条件的优化,并参照液液萃取的方法,对水相中六氯苯,DDT及其代谢产物的萃取效果进行了比较.结果表明,SPME方法比液液萃取方法在检测限和回收率上有很大的提高,其中PDMS对检测六氯苯,DDT及其代谢产物的效果较其它两种萃取头好.

湖北栀子花挥发油的GC/MS分析

利用水蒸气蒸馏法从湖北栀子花鲜花中提取栀子花挥发油。通过 DB 5弹性石英毛细管柱 GC MS分析所得栀子花挥发油 ,共鉴定了 4 0个化合物并测定了其相对含量。湖北栀子花挥发油的主要成分为芳樟醇 ( 1 7 92 %)、茉莉内酯 ( 9 1 1 %)和惕各酸顺 3 己烯酯( 6 5 4 %)

除臭大蒜口服液的GC/MS分析

应用GC/MS联用技术,对除臭大蒜口服液进行了检测,定性鉴定了25种含硫有机化合物。二烯丙基硫醚、甲基烯丙基三硫醚、3-乙烯基-1,2-二硫杂-5-环己烯、2-乙烯基-1,3-二硫杂-5-环己烯和二烯丙基三硫醚是主要组分;二烯丙基四硫醚、烯丙基四硫化氢、2-和3-(2’,3’-二硫杂-5’-己烯基)-3,4-二氢-2H-噻喃、2-(2’-[3’,4’-二氢-2H噻喃基])-1,3-二硫杂-5-环己烯和3-(2’-[3’,4’-二氢-2H-噻喃基])-1,2-二硫杂-5-环己烯是次要组分。最后4种次要组分在

湖泊沉积物中邻苯二甲酸酯类的GC／MS分析

东湖沉积物阴干后用二氯甲烷溶剂萃取，用ＤＢ－５弹性石英毛细管柱ＧＣ／ＭＳ分离鉴定，并结合ｍ／ｚ１４９质量色谱图，确证东湖沉积物中含有９种邻苯二甲酸酯类化合物，它们是邻苯二甲酸二乙酯、二异丁酯、二正丁酯、二己酯、己基辛基酯、二－（２－乙基己基）酯、二辛酯、己基癸基酯和辛基癸基酯，其特征离子及峰度见表１。