PFU微型生物群落水质鉴别及群落参数变化模式的研究

基于PFU微型生物群落参数调查数据,对湖北省汉江两条污染带11个站点和湖南常德市水系15个站点所属水质组别进行了综合分析研究.所得典型鉴别函数能够对水质组别作出有效的鉴别,分类函数对站点的水质组别分类正确率达到96%;群落参数对化学综合污染指数(P)的响应不呈简单的线性关系,群落参数的变化存在一定模式.提出了“转折区”(turninginterval)概念.水质由洁净到严重污染的变化过程中,在转折区内,微型生物群落的5个参数与P的相关性将发生根本性改变:D和Seq与P由正相关转变为负相关,T90%由负相关

DIRECT DETECTION OF PICOSECOND PULSES EMITTED BY AN INJECTION LASER WITH ACTIVE MODE LOCKING.

An Agat-SF linear-scan streak image-converter camera was used to record output pulses of 2. 7 psec duration generated by an injection laser with an external dispersive resonator operated in the active mode-locking regime. The duration of the pulses was determined by the reciprocal of the spectral width and the product of the duration and the spectral width was 0. 30.

Pulsed laser writing of holographic nanosensors

Tuneable optical sensors have been developed to sense chemical stimuli for a range of applications from bioprocess and environmental monitoring to medical diagnostics. Here, we present a porphyrin-functionalised optical sensor based on a holographic grating. The holographic sensor fulfils two key sensing functions simultaneously: it responds to external stimuli and serves as an optical transducer in the visible region of the spectrum. The sensor was fabricated via a 6 nanosecond-pulsed laser (350 mJ, λ = 532 nm) photochemical patterning process that enabled a facile fabrication. A novel porphyrin derivative was synthesised to function as the crosslinker of a polymer matrix, the light-absorbing material, the component of a diffraction grating, as well as the cation chelating agent in the sensor. The use of this multifunctional porphyrin permitted two-step fabrication of a narrow-band light diffracting photonic sensing structure. The resulting structure can be tuned finely to diffract narrow-band light based on the changes in the fringe spacing within the polymer and the system's overall index of refraction. We show the utility of the sensor by demonstrating its reversible colorimetric tuneability in response to variation in concentrations of organic solvents and metal cations (Cu 2+ and Fe2+) in the visible region of the spectrum (λmax ≈ 520-680 nm) with a response time within 50 s. Porphyrin-functionalised optical sensors offer great promise in fields varying from environmental monitoring to biochemical sensing to printable optical devices. This journal is © the Partner Organisations 2014.

适合于芯片集成的被动型铷原子频标

本发明公开了一种适合于芯片集成的被动型铷原子频标，包括量子系统、伺服电路、20MHz压控振荡器和第一2分频器;其中，量子系统由100MHz电离源、Rb87灯、Rb85滤光泡、谐振腔Rb87吸收泡以及光电检测电路构成;伺服电路由低噪声放大器、带通滤波器、缓冲器、模数转换器、控制器、数模转换器、比较器、锁相环电路、第二2分频器、DDS和混频器构成;其中锁相环电路包括342分频器、鉴频鉴相器、电荷泵、滤波器和6840MHz压控振荡器。利用本发明，极大的提高了被动型铷原子频标稳定性和相位噪声指标，降低了被动型铷原子频标的功耗，减小了被动型铷原子频标的重量和体积，便于被动型铷原子频标的芯片集成。

Duplicating "sunlight'' from simple WOLEDs for lighting applications

Simple single-dopant white organic light-emitting devices (WOLEDs) with optimized efficiency/color quality/brightness trade-offs are developed; the white light produced shows the best color quality ever exhibited by WOLEDs at very high brightness, and is even able to duplicate the natural sunlight source.

大别-苏鲁超高压变质带柯石英榴辉岩成因的实验研究——以辉长岩→榴辉岩固相转换为例

本文通过辉长岩在高温、高压下的进变质作用过程的模拟，实现了辉长岩向榴辉岩的转变。在800，2.5Gpa以下，辉长岩生成了石榴石+辉石+长石±尖晶石的矿物组合，在800，2.5Gpa以上，辉长岩则生成石榴+辉石石英的榴辉岩组合。辉长岩向榴辉岩转变过程中存在一个过渡带，过渡带主要的特征是：随压力升高，石榴石逐渐增加，而斜长石逐渐减少。生成的石榴石中，镁铝榴石分子含量随压力的增大而增加，其成因分类属于地幔成因；生成的单斜辉石主要为富镁普通辉石，辉石中硬玉的含量较低。将实验结果与大别山榴辉岩形成条件相比，可以证实：1.大别山榴辉岩形成的温、压条件是在700-900 ℃，2.5Gpa以上；2.大别山柯石英榴辉岩的形成深度至少在80km以上。

Flight simulation

Dr Fuchen Jia, Dr Mayer Patel and Professor Edwin Galea explain how advanced fire models were used to unravel the secrets of Swissair Flight 111, which crashed off the coast of Canada in 1998.

World in motion

Professor Ed Galea CEng, MIFireE provides a welcome to Pedestrian and Evacuation Dynamics 2003, (PED 2003) to be held in London on 20-22 August 2003.

Predicting the past

H. Jiang, S. Gwynne, E.R. Galea, P. Lawrence, F. Jia and H. Ingason model a disco fire in Gothenburg, Sweden to compare the simulation’s predictions with actual events

Electrochemical sensor for catechol and dopamine based on a catalytic molecularly imprinted polymer-conducting polymer hybrid recognition element

One of the difficulties with using molecularly imprinted polymers (MIPs) and other electrically insulating materials as the recognition element in electrochemical sensors is the lack of a direct path for the conduction of electrons from the active sites to the electrode. We have sought to address this problem through the preparation and characterization of novel hybrid materials combining a catalytic MIP, capable of oxidizing the template, catechol, with an electrically conducting polymer. In this way a network of "molecular wires" assists in the conduction of electrons from the active sites within the MIP to the electrode surface. This was made possible by the design of a new monomer that combines orthogonal polymerizable functionality; comprising an aniline group and a methacrylamide. Conducting films were prepared on the surface of electrodes (Au on glass) by electropolymerization of the aniline moiety. A layer of MIP was photochemically grafted over the polyaniline, via N,N'-diethyldithiocarbamic acid benzyl ester (iniferter) activation of the methacrylamide groups. Detection of catechol by the hybrid-MIP sensor was found to be specific, and catechol oxidation was detected by cyclic voltammetry at the optimized operating conditions: potential range -0.6 V to +0.8 V (vs Ag/AgCl), scan rate 50 mV/s, PBS pH 7.4. The calibration curve for catechol was found to be linear to 144 µM, with a limit of detection of 228 nM. Catechol and dopamine were detected by the sensor, whereas analogues and potentially interfering compounds, including phenol, resorcinol, hydroquinone, serotonin, and ascorbic acid, had minimal effect (=3%) on the detection of either analyte. Nonimprinted hybrid electrodes and bare gold electrodes failed to give any response to catechol at concentrations below 0.5 mM. Finally, the catalytic properties of the sensor were characterized by chronoamperometry and were found to be consistent with Michaelis-Menten kinetics. © 2009 American Chemical Society.