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1.
Hydrodynamic cavitation experiments in microfluidic systems have been performed with an aqueous solution of luminol as the working fluid. In order to identify where and how much reactive radical species are formed by the violent bubble collapse, the resulting chemiluminescent oxidation reaction of luminol was scrutinized downstream of a constriction in the microchannel. An original method was developed in order to map the intensity of chemiluminescence emitted from the micro-flow, allowing us to localize the region where radicals are produced. Time averaged void fraction measurements performed by laser induced fluorescence experiments were also used to determine the cavitation cloud position. The combination void fraction and chemiluminescence two-dimensional mapping demonstrated that the maximum chemiluminescent intensity area was found just downstream of the cavitation clouds. Furthermore, the radical yield can be obtained with our single photon counting technique. The maximum radical production rates of 1.2*107 OH/s and radical production per processed liquid volume of 2.15*1010 HO/l were observed. The proposed technique allows for two-dimensional characterisation of radical production in the microfluidic flow and could be a quick, non-intrusive way to optimise hydrodynamic cavitation reactor design and operating parameters, leading to enhancements in wastewater treatments and other process intensifications. 相似文献
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Environmental Fenton chemistry has been poorly constrained within the marine environment at a multi-component level. A simple, unique, reconfiguration of a flow-injection analytical system combined with luminol chemiluminescence allows quasi-simultaneously the measurement, using a single load-inject valve and a single photon multiplier tube, of reduced iron, Fe(II), and hydrogen peroxide. The system enables rapid, every 22 s, measurements with good accuracy at environmentally relevant concentrations, less than 5% relative standard deviations on both a 5 nM Fe(II) standard and a 60 nM hydrogen peroxide standard. Limits of detection were as low as 40 pM Fe(II) and 100 pM hydrogen peroxide. The system showed excellent capability by measuring from within an organic rich seawater the photochemically induced production of Fe(II) and hydrogen peroxide and their subsequent cycling and Fenton like interactions. 相似文献
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The electrochemiluminescence (ECL) of luminol on indium tin oxide (ITO) glass was high even under a low potential around 0.4-0.5 V, which was quite different from other electrodes such as platinum. ITO nanoparticles were synthesized and used in the research on ITO glass in the ECL process. A static interaction between ITO and luminol is confirmed from UV-vis and fluorescence spectra. Then the ECL enhancement can be supposed to originate from the adsorption of luminol on ITO, which facilitated luminol’s oxidization to the excited state, giving out ECL. On the other hand, ITO can catalyze the generation of reactive oxygen species (ROSs), similar to some other nanomaterials, which also favored the ECL enhancement of luminol. 相似文献
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基于在碱性介质中,克百威抑制鲁米诺-过氧化氢-叶绿素铜钠体系的化学发光,提出了流动注射-抑制化学发光法测定克百威含量的方法。试验结果表明:叶绿素铜钠对克百威荧光猝灭过程是静态猝灭过程,叶绿素铜钠与克百威结合形成物质的量比为1比1的稳定配合物,平衡常数(K0)为3.41×105L.mol-1(25℃),结合距离(r)为0.39 nm。克百威质量浓度在0.08~2.00 mg.L-1范围内与其发光强度呈线性关系,方法检出限(3σ/k)为0.03 mg.L-1。此法用于克百威杀虫剂样品的分析,测得方法的平均加标回收率为101.5%。 相似文献
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Picomole‐level Formaldehyde Determination in Gaseous and Beer Samples Using Flow Injection Chemiluminescence Analysis 下载免费PDF全文
Based on the linear enhancement of formaldehyde (FA) within 7.0 ~ 1000 pmol l?1 on luminol—bovine serum albumin (BSA) chemiluminescence (CL) system, FA determination in air and beer samples using CL with flow injection (FI) was proposed. The detection limit was 2.5 pmol l?1 (3σ) and the relative standard deviations were less than 4.5% (n = 7). At a flow rate of 2.0 mL min?1, a whole analysis from sampling to washing only needed 32 s, offering a sample throughput of 112 h?1. This proposed method was successfully utilized to determine FA vapor pressure in liquid (121.8 ± 3.8 Pa), FA content in real air sample (8.93 ± 0.03 mg m?3), and FA levels in beer (199.5 ± 5.6 ~ 225.2 ± 3.5 mg l?1), giving determination recoveries from 90.7% to 109.3%. The mechanism of BSA—FA interaction was also investigated, showing FA binding to BSA was a spontaneous process mainly through hydrogen bonding and van der Waals force by FI‐CL, with binding constant K of 1.89 × 106 l mol?1 and the number of binding sites n of 0.86. Molecular docking analysis further revealed FA could enter into the pocket at subdomain IIA of BSA, with K of 1.71 × 105 l mol?1 and ΔG of ‐29.68 kJ mol?1. 相似文献
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Interaction of luminol with phosphomolybdic, phosphovanadomolybdic and silicomolybdic acids was studied by examination of chemiluminescence spectra, measurement of ESR spectra, investigation of reaction order, and elucidation of inhibition effects. A scheme of the reaction mechanism is proposed. 相似文献
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Audrey Sassolas Loïc J. Blum Béatrice D. Leca-Bouvier 《Analytical and bioanalytical chemistry》2009,394(4):971-980
Performant reagentless electrochemiluminescent (ECL) (bio)sensors have been developed using polymeric luminol as the luminophore.
The polyluminol film is obtained by cyclic voltammetry (CV) on a screen-printed electrode either in a commonly used H2SO4 medium or under more original near-neutral buffered conditions. ECL responses obtained after performing polymerization either
at acidic pH or at pH 6 have been compared. It appears that polyluminol formed in near-neutral medium gives the best responses
for hydrogen peroxide detection. Polymerization at pH 6 by cyclic voltammetry gives a linear range extending from 8 × 10−8 to 1.3 × 10−4 M H2O2 concentrations. Based on this performant sensor for hydrogen peroxide detection, an enzymatic biosensor has been developed
by associating the polyluminol film with an H2O2-producing oxidase. Here, choline oxidase (ChOD) has been chosen as a model enzyme. To develop the biosensor, luminol has
been polymerized at pH 6 by CV, and then an enzyme-entrapping matrix has been formed on the above modified working electrode.
Different biological (chitosan, agarose, and alginate) and chemical (silica gels, photopolymers, or reticulated matrices)
gels have been tested. Best performances have been obtained by associating a ChOD-immobilizing photopolymer with the polyluminol
film. In this case, choline can be detected with a linear range extending from 8 × 10−8 to 1.3 × 10−4 M.
This paper is based on the results presented in a poster that received a Poster Award on the occasion of XIII International
Symposium on Luminescence Spectrometry in Bologna, Italy, on September, 7th-11th, 2008. 相似文献