Pulse amplification of a single-frequency cr:forsterite laser

Stable single-longitudinal-mode operation of a tunable gain-switched Cr:forsterite oscillator-amplifier system is reported. A novel coupled-cavity oscillator configuration provides a low-threshold fluence of 0.3 J cm(-2), making the system attractive for laser media with low gain or high parasitic loss. Nearly transform-limited pulses with instrument-limited bandwidths of 150 MHz have been obtained across a 100-nm wavelength range, limited by the cavity optics. A range of forsterite crystals with Cr(4+) concentration in the 3-21 x 10(18)-cm(-3) range has been used for investigation of amplifier performance in single- and double-pass configurations.     

“免签”怎能是互联网旅游新爆点？

随着O2O概念的火热,在线旅游的“玩家们”重新点燃了市场的热情。老牌劲旅携程与艺龙焕发新生,上市新科去哪儿和途牛也备受资本市场追捧,就连BAT（百度、阿里巴巴、腾讯）也都加速旅游O2O的布局。如何在白热化的市场中找到一个全新突破口,成为众多企业所关注的焦点。     

Surface-enhanced Raman scattering from intracellular and extracellular bacterial locations

While surface-enhanced Raman scattering (SERS) can increase the Raman cross-section by 4-6 orders of magnitude, for SERS to be effective it is necessary for the analyte to be either chemically bonded or within close proximity to the metal surface used. Therefore most studies investigating the biochemical constituents of microorganisms have introduced an external supply of gold or silver nanoparticles. As a consequence, the study of bacteria by SERS has to date been focused almost exclusively on the extracellular analysis of the Gram-negative outer cell membrane. Bacterial cells typically measure as little as 0.5 by 1 mum, and it is difficult to introduce a nanometer sized colloidal metal particle into this tiny environment. However, dissimilatory metal-reducing bacteria, including Shewanella and Geobacter species, can reduce a wide range of high valence metal ions, often within the cell, and for Ag(I) and Au(III) this can result in the formation of colloidal zero-valent particles. Here we report, for the first time, SERS of the bacterium Geobacter sulfurreducens facilitated by colloidal gold particles precipitated within the cell. In addition, we show SERS from the same organism following reduction of ionic silver, which results in colloidal silver depositions on the cell surface.     

取消共享文件夹上的手

在局域网环境中,其他电脑想访问自己的电脑,将自己的电脑的某个硬盘分区或者文件夹设置为“共享”就可以了。默认情况下,Windows系统为了便于区分共享文件夹,文件夹图标上都会显示一只“手”,而在Windows7系统中则为“两个小人”（如图1）,表明已经共享。但问题出现了,我发现同事电脑上有很机密的资料,如果拷走,资料更新后我无法查看;如果共享该机密文件夹,     

新春视频贺卡在线合成

自从DC／DV飞入咱平常百姓家之后,可以说是春节年年过,照片年年拍,视频年年掇,祝福手机短倍是年年发,这一切都已经是顺理成章和老套的做法,对于这些拍摄的团圆饭或者元宵节的照片,除了导入电脑保存浏览以外,不妨将拍摄的照片做成视频贺卡发送吧,     

音乐储存和分享的酷硬盘

从网上下载或者自己从CD中抓取转换了MP3格式的音乐,除了存硬盘巾保存以外,还想与更多的网友分享,或者想将MP3引用到博客、QQ空间中。然而现存的很多网络空间都不支持外链,要不就是容量有限制等等,遇到这些难题不妨试试“酷狗音乐硬盘”（http：／／disk．kugou．com）,音乐储存和分享都变得更加轻松和简单。     

Impact of UV disinfection on microbially available phosphorus,organic carbon,and microbial growth in drinking water

UV irradiation at a wavelength of 253.7 nm (UV(254)) is commonly used for drinking water disinfection. UV radiation is known to convert organically combined phosphorus to orthophosphate and to degrade natural organic matter. We studied if UV disinfection increases the amount of microbially available forms of organic carbon and phosphorus in drinking waters with different characteristics, and if these changes in water chemical quality could enhance the microbial growth in drinking water. The UV(254) dose (15-50 mWs/cm(2)) used in waterworks reduced the concentration of assimilable organic carbon and the sum of the molecular size fractions. The release of microbially available phosphorus needed higher doses (204 mWs/cm(2)) of UV(254) radiation. Of bacteria in drinking water, 90% were inactivated with UV(254)-irradiation doses below 50 mWs/cm(2). A high dose (501 mWs/cm(2)) of UV(254) radiation inhibited the microbial growth in water.     

The behaviour of technetium during microbial reduction in amended soils from Dounreay, UK

Radioactive technetium-99 forms during nuclear fission and has been found as a contaminant at sites where nuclear wastes have been processed or stored. Here we describe results from microcosm experiments containing soil samples representative of the UKAEA site at Dounreay to examine the effect of varying solution chemistry on the fate of technetium during microbial reduction. Analysis of a suite of stable element redox indicators demonstrated that microbial activity occurred in a range of microcosm experiments including unamended Dounreay sediments, carbonate buffered sediments, and microcosms amended with ethylenediaminetetraacetic acid (EDTA) a complexing ligand used in nuclear fuel cycle operations. During the development of anoxia mediated by indigenous microbial populations, TcO4- was removed from solution in experiments. In all cases, the removal of TcO4- from solution occurred during active microbial Fe(III)-reduction when Fe(II) was growing into the microcosms. Tc removal was most likely via reduction of TcO4- to poorly soluble Tc(IV) which is retained on the sediments. The potential stability of Tc associated with the soil to remobilisation via complexation with EDTA was examined as reduced Tc-labelled sediments were contacted with a de-oxygenated EDTA solution. No remobilisation of Tc(IV) in the presence of EDTA was observed.     

Effects of chemical sludge disintegration on the performances of wastewater treatment by membrane bioreactor

A new wastewater treatment process combining a membrane bioreactor (MBR) with chemical sludge disintegration was tested in bench scale experiments. In particular, the effects of the disintegration treatment on the excess sludge production in MBR were investigated. Two MBRs were operated. In one reactor, a part of the mixed liquor was treated with NaOH and ozone gas consecutively and was returned to the bioreactor. The flow rate of the sludge disintegration stream was 1.5% of the influent flow rate. During the 200 days of operation, the MLSS level in the bioreactor with the disintegration treatment was maintained relatively constant at the range of 10,000-11,000 mg/L while it increased steadily up to 25,000 mg/L in the absence of the treatment. In the MBR with the sludge disintegration, relatively constant transmembrane pressures (TMPs) could be maintained for more than 6 months while the MBR without disintegration showed an abrupt increase of TMP in the later phase of the operation. In conclusion, a complete control of excess sludge production in the membrane-coupled bioreactor was possible without significant deterioration of the treated water quality and membrane performances.