腔靶等离子体辐射温度空间分布测量

本文描述了用膜吸收法测量激光等离子体辐射温度空间分布的原理和方法给出了柱形缝靶轴向辐射温度随空间位置变化的特征,对测量结果进行了分析讨论。     

用超磁致伸缩调谐光纤光栅的光分/插复用器

提出并研究了一种新型多信道切换的全光分/插复用器,它主要由光纤Bragg光栅(FBG)和一对光环行器组成.采用了一种高效的超磁致伸缩材料(GMM)使FBG产生有效的Bragg波长偏移.用控制电流来调控FBG的应变和Bragg波长偏移.用4只相同的FBG与波长叠加技术相结合,可建立能提供15种不同下路信道方式的OADM.     

Measurements of FRET in a glucose-sensitive affinity system with frequency-domain lifetime spectroscopy

We report measurements of fluorescence resonance energy transfer (FRET) for glucose sensing in an established concanavalin A–dextran affinity system using frequency‐domain lifetime spectroscopy. A dextran (MW 2000000) labeled with a small fluorescent donor molecule, Alexa Fluor 568, was used to competitively bind to a sugar‐binding protein, concanavalin A, labeled with acceptor molecule, Alexa Fluor 647, in the presence of glucose. The FRET‐quenching kinetics of the donor were analyzed from frequency‐domain measurements as a function of both glucose and acceptor‐protein concentrations using a Förster‐type decay kinetics model. The results show that the frequency‐domain measurements and donor decay kinetics can quantitatively indicate changes in the competitive binding of 0.09 μM dextran to labeled concanavalin A at a solution concentration of 10.67 μM in the presence of glucose at concentrations ranging from 0 to 224 mg/dL.     

腔靶X射线辐射对称特性实验观测

在“神光”装置上用两种特殊结构的实验靶型,通过两个不同方位的诊断孔观测腔内壁Ｘ光再辐射的空间能谱结构和Ｘ光辐射总量,分别研究了与激光第一打击面完全对称和不对称的腔内壁（两个被观测位置相差９０°）Ｘ光辐射能谱和辐射能量的对称性,并对测量结果进行了简要的分析讨论．     

Nafion化学修饰圆盘预富集-石墨炉 原子吸收联用法对牛血超氧化物歧化酶中铜、锌分布状态的研究

本文研究了Nafion化学修饰钨丝圆盘预富集-石墨炉原子吸收(GFAAS)方法测定牛血超氧化物歧化酶(SOD)中游离态Cu～(2+)及Zn～(2+)的方法,并用GFAAS法直接测定SOD中铜、锌的总量,证实了牛血SOD中金属辅基铜、锌原子个数比为1:1,初步探讨了一定浓度的牛血SOD中Cu～(2+)、Zn～(2+)的表观离解平衡常数。为提高SOD的活性和稳定性的研究,提供了一种有效的方法。     

The study of nafion/xanthine oxidase/au colloid chemically modified biosensor and its application in the determination of hypoxanthine in myocardial cells in vivo

A novel hypoxanthine (Hx) microsensor was constructed. In this work, Nafion xanthine oxidase (XOD) and Au colloid were immobilized onto the surface of a Pt microelectrode. The enzyme biosensor displayed a quick and sensitive response to Hx. Under physiological conditions, a low detection limit, with high selectivity and sensitivity for Hx determination were obtained. The oxidation current [investigated using current-time (I-t) plots] was linear with Hx concentration ranging from 2.0 x 10(-7) to 2.0 x 10(-5) mol L(-1) with a calculated detection limit of 1.0 x 10(-7) mol L(-1) (S/N of 3). The biosensor should be promising for in vivo measurement of Hx without interferences and fouling. The change of Hx concentration in cardiac myocytes stimulated by L-arginine (L-Arg) and acetylcholine (Ach) was also studied.     

FDU-15-Pt composites with different Pt loading and their electrocatalytic reduction to ultratrace nitroaromatic compounds

FDU-15 is a hexagonal mesoporous material with nanometer-sized, highly ordered arrays and large special surface area. In this work, FDU-15-Pt with 2.0%, 5.0% and 8.0% Pt loading were synthesised and used for electrochemical detection of trace nitroaromatic compounds (NACs). The FDU-15-Pt samples were characterised by CO Chemisorption, transmission electron microscopy (TEM) and X-ray diffraction (XRD). It has been demonstrated that FDU-15-Pt with 2.0% Pt loading has the smallest Pt particle size of 2.9?nm, highest Pt metal dispersion of 37.7% and largest Pt metal surface area of 21.36?m^2?g^?1. The FDU-15-Pt/PDDA modified electrode were assembled by electrostatic adsorption of Poly (diallyldimethylammonium chloride) (PDDA) and FDU-15-Pt. The 2.0% FDU-15-Pt modified sensor showed higher selectivity for NACs than those of 5.0% and 8.0% FDU-15-Pt, which were verified by electrochemical experiments. A linear response over TNT concentration ranging from 8.8?×?10^?9?M to 1.2?×?10^?5 M was exhibited with a low detection limit of 2.9?×?10^?9?M (S/N?=?3). Moreover, the proposed 2.0% FDU-15-Pt/PDDA modified sensor has been applied to the detection of NACs in spiked environmental water samples and shows promise for fast and accurate determination of trace NACs in real samples.     

Excited‐state hydrogen bond strengthening of coumarin 153 in ethanol solvent: a TDDFT study

So far, coumarin dyes have been extensively studied with various means to understand their photophysical behaviors and photochemical properties. Here, our performing time‐dependent density functional theory calculation is aimed at exploring the excited‐state hydrogen bonding dynamics of coumarin 153 (C153) in protic ethanol (EtOH) solvent. The calculated results suggest that the excited‐state hydrogen bond C?O?H?O between C?O group and O?H group in the C153‐EtOH complex is strengthened, and the S₀ → S₁ transition of the complex corresponds to the highest occupied molecular orbital (HOMO) hopping to the lowest unoccupied molecular orbital (LUMO). The excited‐state hydrogen bond strengthening has been further confirmed by its larger binding energy in the S₁ state than in the S₀ state. In addition, because of the formation of the hydrogen bond C?O?H?O, a red shift of about 7 nm occurs in the electronic spectra of the C153‐EtOH complex, which is in good accordance with the experiment result. Copyright © 2016 John Wiley & Sons, Ltd.     

利用自由基引发的1,2-炔基迁移实现非活性烯烃的炔膦酰化

研究了1,4-烯炔衍生物与二芳基膦氧化物在银介导下发生的炔酰化反应.该反应利用自由基引发的1,2-炔基迁移策略合成了一系列γ-酮膦氧化物,产率适中.该反应机理可能涉及膦中心自由基与乙烯基的加成、3-exo-dig环化和1,2-炔基迁移等连续的过程,一步形成了C-P、C-C键等化学键,实现了非活性烯烃的双官能化.     

Acetone,butanone, pentanone,hexanone and heptanone in the headspace of aqueous solution and urine studied by selected ion flow tube mass spectrometry

Urine is commonly analysed in clinical practice by a variety of liquid‐phase techniques to check for excessive ketone bodies, proteins and salts to name just a few compounds. However, little work has been carried out to measure the volatile compounds emitted by urine since these do not yet have an established role in clinical diagnosis. There is, however, a growing body of evidence that these volatile compounds can be indicators of adverse physiological conditions and disease and with the advent of sensitive gas‐phase analytical methods they can be quickly quantified in urine headspace and potentially provide valuable support for clinical diagnosis. Thus, we are developing selected ion flow tube mass spectrometry, SIFT‐MS, for the real‐time analysis of urine headspace, ultimately to support rapid diagnosis in the clinical environment. In this paper we focus on volatile ketones in the headspace of aqueous solutions and urine donated by three healthy volunteers. Using SIFT‐MS, we have unambiguously quantified in urine headspace acetone, by far the most abundant ketone, butanone, pentanone, hexanone and heptanone using NO⁺ precursor ions. Further to this, we have determined the Henry's Law coefficients, HLC, for these ketones in aqueous solution to allow the liquid‐phase concentrations in urine to be estimated from headspace levels of their vapours. In addition, the influence of the addition of physiological amounts of dissolved urea, sodium chloride and hydrochloric acid on the partitioning of these ketones between the aqueous phase and gas phase has been investigated and found to be small, which gives greater credence to the use of the HLC obtained using aqueous solutions for the estimation of ketone concentrations in urine. Finally, parallel measurements of the levels of acetone in exhaled breath and urine headspace have been obtained and shown to be very similar, which gives support to the previous deduction from breath analysis that acetone is a truly systemic compound. Copyright © 2009 John Wiley & Sons, Ltd.