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1.
An improved accuracy is researched in flat and silicon based nano-calorimeters related to fluid reaction via drop-to-drop 'reaction' or via a steady state in continuous injection of two reactants inside a working chamber. Two types of the experimental aspects of the sensitivity changes, related to 3-D effects, are described: drop effects and volume rate effects. To increase the accuracy, well-controlled joule measurements are dissipated in the manufacturer resistance and in several resistances in carefully controlled experiments. The shape factor (SF) values reduce the manufacturer's joule sensitivity up to fifty per cent. a working methodology is proposed: the results are compared with the standard TRIS reaction. The results suggest that the systematic error can be reduced to ±5%. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

2.
Micro-calorimetric devices using Si-based sensors are very useful for the study of gas–solid reactions, in which very low mass of reactants are necessary. But in fact the consequence of using flat detectors is an increase of the uncertainty in the measured energy. In this work a calorimetric gas sensor based on Xensor chip is analysed studying the local x–y contributions of dissipation to the sensitivity related to the value in the centre. We study also the effects of the gas-flow on the sensitivity, comparing the results obtained with two Xensor type chips. Finally we carry out a deeper analysis of the x–y effects on the calorimetric detector for dissipations in the reactant shell extremely close to the detector surface to visualize the link between the power density distribution and the output signal.  相似文献   

3.
Summary Using an RC model, the behavior of a TAM high-performance calorimeter (Thermometric AB, Sweden) equipped with a flow-mixing insertion vessel using independent pumps for each reactant is studied. The model shows a reliable sensitivity behavior for mixtures realized inside the cell. The model behavior is compared with experimental measurements.</o:p>  相似文献   

4.
The experimental analysis of conventional conduction calorimeters shows excellent reproducibility and relevant systematic errors in comparison with thermodynamic values established via adiabatic calorimeters. Two examples: a DSC and a liquid flow device are schematically analyzed. When an increased accuracy will be obtained the positional effects on the experimental set-up and on the measurement process need to be modelled. From experimental measurements realized on the Xensor liquid nano-calorimeter representative models can be built. To evaluate the reliability of measurement routines, established from experimental basis, several different dissipation structures inside the working space can be simulated. Two experimental configurations related to drop to drop reaction and to continuous mixing are modelled via RC approach. The RC formalism is extended to evaluate the carried energy effect produced by the continuous inflow/outflow of reactants in the mixing enthalpy chamber. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

5.
The miniaturization of the calorimetric devices to ‘nano-sized’ scale reduces progressively the available surface of the heat flux detectors with an increase in systematic uncertainty. By means of several Joule and laser signals, the positional effects in ‘liquid microcalorimeter’ micro-sized chip are evaluated. This allows the introduction of a 3-D coefficient, modifying the standard Joule sensitivity. The shape factor includes the surface and the volume effects. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

6.
A. Krauss 《Thermochimica Acta》2006,445(2):126-132
A transportable water calorimeter for the determination of the quantity of absorbed dose to water in radiotherapy beams has been developed at the PTB and is presented in detail in this investigation. Heat conduction effects occurring in the calorimeter are studied for different lateral sizes of high-energy photon beams, for different depth dose distributions of electron beams and for a scanned-beam irradiation with a heavy ion beam. The corresponding correction factors are calculated and arguments are given under which conditions these can adequately be applied.  相似文献   

7.
对合成的莫达非尼试验品用液相色谱(HPLC)鉴定其纯度后,同时进行元素(EMA)、红外光谱(IR)、紫外光谱(UV)、质谱(MS)、差热()DTA)、核磁共振(NMR)氢谱及碳谱分析,根据分析的结果进行解析,确证了其化学结构为莫达非尼。  相似文献   

8.
Complex formation of copper(II) with N,N-dimethylformamide(DMF) has been investigated calorimetrically in acetonitrile at 25°C. Calorimetric titration curves obtained are explained in terms of formation of [Cu(dmf) n ]2+ (n=1–4, 6) and their formation constants, enthalpies and entropies were determined. Formation of [Cu(dmf)5]2+ is uncertain. The stepwise enthalpies S 3 0 and entropies S n 0 at each consecutive step are all negative except for S 3 0 . The overall enthalpies of formation of [Cu(dmf)6]2+ is –(77.8±5.4) kJ-mol–1, which is compared with the enthalpy of transfer of copper(II) ion, H t o =–79.7 kJ-mol–1, from acetonitrile to DMF.  相似文献   

9.
Two new complexes based on 4,4′-[1,3-phenylenebis(oxy)]diphthalic acid (H4L) ligands were synthesized, namely, [Cd2(L)(1,10-phen)2(H2O)]n( 1 ) and [Co2(L)(1,10-phen)2(H2O)]n( 2 ), in which 2D structures transform into 3D supramolecular structures by C H···π interaction. The proton conductivity of complexes 1 and 2 at low temperature is close (σ1 = 3.12 × 10−8 S cm−1 and σ2 = 3.81 × 10−8 S cm−1 at 30°C), but these two complexes show different conduction mechanisms. The Vehicular mechanism in 1 is caused by the O···H/H···O contact in 1 , which is stronger than 2 , and the Grotthuss mechanism in 2 is caused by the N···H/H···N contact in 2 , which is stronger than 1 . At the same time, complex 1 showed excellent antibacterial properties in vitro, mainly reflected in that five kinds of bacteria (Escherichia coli, Bacillus amyloliquefaciens, Pantoea agglomerans, Pseudomonas putida, and Pectobacterium carotovora) could play an obvious inhibitory effect in the concentration range of 20 μg·ml−1.  相似文献   

10.
评述了Ge-132定性方法的文献资料。实验证明对于Ge-132的定性方法,除了用荧光酮检测Ge外,羧基的鉴定也是必要的。  相似文献   

11.
峰形分析辅助色谱定性的研究   总被引:1,自引:0,他引:1  
蔡春平  梁鸣  翁若荣 《色谱》1999,17(3):293-295
尝试建立了一种通过峰形分析进行色谱定性的方法。首先选择一组既易于测量,又能较好地表征色谱峰形特性的参数(峰宽、不对称因子)作为峰形分析的基础;其次,通过理论和实验证明:对于保留时间与标准物质非常接近的未知组分,可将样品与标准物质混合进样,得到重叠谱图(表观为单峰),然后通过对重叠谱峰与标准物质谱峰的峰形分析与比较,达到对未知物定性的目的。  相似文献   

12.
王庆国  李小文  刘波  蔡力行  程镕时 《色谱》2008,26(2):262-265
差减凝胶渗透色谱(D-GPC)以已知的标准样品溶液作淋洗剂,样品溶液作进样试液,通过内部差减,快速准确地给出样品溶液与标准样品溶液各组分之间的差异。以聚乙二醇(PEG200)的浓度识别以及3种啤酒的品牌识别为例,通过比较常规GPC与D-GPC所得到的实验结果,说明D-GPC方法在啤酒质量控制和品牌识别等方面所具有的应用价值。  相似文献   

13.
广灭灵的制备、纯化及结构鉴定   总被引:3,自引:0,他引:3  
合成了广灭灵农药粗品,采用柱层析分离技术,以硅胶为填料,乙酸乙脂:石油醚(沸点30℃-60℃)=1:4为展开剂(Rt=0.5)进行了纯化。用元素分析法(EAS)、熔点法(MDS)、紫外光谱法(UV)、红外光谱法(IR)、质谱法(MS)及核磁共振法(^1H NMR^13、^13C NMR)进行了结构鉴定及表征。  相似文献   

14.
Purification and Structure Identification of Hyaluronic Acid   总被引:1,自引:0,他引:1  
Polysaccharide produced by mutated strain of Streptococcus zooepidemicus was purified by the procedures including Savage method, quaternary ammonium compound precipitation, DEAE-cellulose(DE52) chromatography and Sephadex G-75 gel filtration. The structure of the purified polysaccharide has been characterized by means of chemical composition analysis,13C NMR spectrum, infrared spectrum and circular dichroism (CD). All the results showed that the purified polysaccharide was hyaluronic acid (HA). The single helix conformation of the purified HA was determined by Congo red experiment. The molecular weight of the HA was about 1.16×106D, which was measured by viscosity method.  相似文献   

15.
The possibility in principle is shown of using the stripping voltammetry method for identification of alkaloids with the help of a test system in the form of an electrolyte solution containing a set of cations of different metals.  相似文献   

16.
报道了两种生物质谱技术ESI-MS和MALDI-MS在鉴定乙酰化修饰蛋白BSA-ac中的应用研究结果. 乙酰化修饰蛋白通过特征碎裂峰m/z 126.1或MS/MS质谱图中相差一个赖氨酸的相邻b或y离子之间170 Da分子量的差异确证赖氨酸乙酰化修饰, 并且后者提供具体修饰位点信息. 研究提示ESI-MS和MALDI-MS两种质谱技术均可用于鉴定实际复杂样品中的乙酰化蛋白, 且在乙酰化蛋白的鉴定中各有其优点.  相似文献   

17.
通过反相高效液相色谱(RP-HPLC)分析小黑麦种子醇溶蛋白,对供试的18个不同品种的小黑麦进行了品种鉴定和倍性水平鉴定,同时也对育种系谱相同的品种进行了系谱证实。  相似文献   

18.
We report a method for precisely identifying and locating the pollen of different species in a microscope based on multihyperspectral imaging. Since pollen species are complicated and difficult to identify by one feature, both fluorescence and transmission spectral images of the samples were obtained and used for the identification together with their morphologic features. Three different species of pollens were used as test samples for investigation. The results showed that the accuracy reached 99.5%, which was a significant improvement comparing with the single spectral detection. Because more information was taken into consideration, this method has great potential for the precise identification of biological specimens.  相似文献   

19.
冰片在中药中被广泛应用。利用前药原理,对冰片母体进行修饰,以冰片和3,5-二硝基苯甲酸为原料,以对甲苯磺酸为催化剂,合成了3,5-二硝基苯甲酸冰片酯,目标化合物的结构经FT-IR、13C NMR、1H NMR和元素分析加以确证。该化合物具有一定的研究开发价值。  相似文献   

20.
A novel Zn(II) metal-organic framework [Zn4O(C30H12F4O4S8)3]n, namely ZnBPD-4F4TS, has been constructed from a fluoro- and thiophenethio-functionalized ligand 2,2′,5,5′-tetrafluoro-3,3′,6,6′-tetrakis(2-thiophenethio)-4,4′-biphenyl dicarboxylic acid (H2BPD-4F4TS). ZnBPD-4F4TS shows a broad green emission around 520 nm in solid state luminescence, with a Commission International De L’Eclairage (CIE) coordinate at x = 0.264, y = 0.403. Since d10-configured Zn(II) is electrochemically inert, its photoluminescence is likely ascribed to ligand-based luminescence which originates from the well-conjugated system of phenyl and thiophenethio moieties. Its luminescent intensities diminish to different extents when exposed to various metal ions, indicating its potential as an optical sensor for detecting metal ion species. Furthermore, ZnBPD-4F4TS and its NH4Br-loaded composite, NH4Br@ZnBPD-4F4TS, were used for proton conduction measurements in different relative humidity (RH) levels and temperatures. Original ZnBPD-4F4TS shows a low proton conductivity of 9.47 × 10−10 S cm−1 while NH4Br@ZnBPD-4F4TS shows a more than 25,000-fold enhanced value of 2.38 × 105 S cm−1 at 40 °C and 90% RH. Both of the proton transport processes in ZnBPD-4F4TS and NH4Br@ZnBPD-4F4TS belong to the Grotthuss mechanism with Ea = 0.40 and 0.32 eV, respectively.  相似文献   

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