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排序方式: 共有111条查询结果,搜索用时 78 毫秒
1.
M. Battilotti C. Colapicchioni I. Giannini F. Porcelli L. Campanella M. Cordatore F. Mazzei M. Tomassetti 《Analytica chimica acta》1989
A new type of biosensor based on the coupling of an enzyme to an ion-selective membrane containing a conducting polymer is evaluated. The results obtained with the enzyme field- effect transistor (ENFET) and the ion-selective electrode (ISE) for the determination of creatinine and urea are compared. The presence of the conducting polymer significantly lowers the detection limit for creatinine by one decade to 10?7 and 10?4 M for the ENFET and ISE, respectively. The determination of urea in urine and serum with the ENFET was carried out, and the results correlated well with those obtained by spectrophotometry. 相似文献
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膜的动电特性研究中,往往采用流动电位方法。该方法中,Ag-Ag Cl测试电极的质量是影响测试准确性的关键要素。本文采用正交试验设计和方差分析,着重考察电解法制备Ag-Ag Cl电极过程中,电流强度(I)、氯化时间(t)、电解质溶液浓度(CHCl)、电极来源(n)、烘烤温度(T)、活化电极溶液浓度(CKCl)等因素对Ag-Ag Cl电极稳定性的影响。得到Ag-Ag Cl电极的最优制备参数为:电流密度3.0m A/cm2,氯化时间50min,盐酸浓度0.1mol·L-1,烘烤温度120℃,活化电极溶液(KCl)浓度0.001mol·L-1;最显著影响因素为电极来源,显著影响因素为氯化时间和烘烤温度。对最优条件组合下制备的AgAg Cl电极,进行了稳定性实验,结果表明:制备的电极具有较好的稳定性,24h内电极电位漂移量小于0.10mv,7天内电极电位漂移量小于0.2mv;在聚偏氟乙烯中空纤维超滤膜流动电位测试中,流动电位与流动压差具有良好的线性和可重复性,回归曲线R20.99,变化规律符合Helmholtz-Smoluehowski公式,可以较好满足膜的流动电位测试要求。 相似文献
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New, rigorous results for the tearing island saturation problem are presented. These results are valid for the realistic case where the magnetic island structure is non-symmetric about the reconnection surface and the electron temperature, on which the electrical resistivity depends, is evolved self-consistently with the island growth. 相似文献
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Opper AK Korkmaz E Hutcheon DA Abegg R Davis CA Finlay RW Green PW Greeniaus LG Jordan DV Niskanen JA O'Rielly GV Porcelli TA Reitzner SD Walden PL Yen S 《Physical review letters》2003,91(21):212302
The forward-backward asymmetry in np-->dpi(0), which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2+/-8.0(stat)+/-5.5(syst)]x10(-4), at an incident neutron energy of 279.5 MeV. This observable is compared to recent chiral effective field theory calculations, with implications regarding the du quark mass difference. 相似文献
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Porcelli TA Adamczak A Bailey JM Beer GA Douglas JL Faifman MP Fujiwara MC Huber TM Kammel P Kim SK Knowles PE Kunselman AR Maier M Markushin VE Marshall GM Mason GR Mulhauser F Olin A Petitjean C Zmeskal J;TRIUMF Muonic Hydrogen Collaboration 《Physical review letters》2001,86(17):3763-3766
Measurements of muon-catalyzed dt fusion ( d(mu)t-->4He + n + mu(-)) in solid HD have been performed. The theory describing the energy dependent resonant molecular formation rate for the reaction (mu)t + HD-->[(d(mu)t)pee](*) is compared to experimental results in a pure solid HD target. Constraints on the rates are inferred through the use of a Monte Carlo model developed specifically for the experiment. From the time-of-flight analysis of fusion events in 16 and 37 microg x cm(-2) targets, an average formation rate consistent with 0.897+/-(0.046)(stat)+/-(0.166)(syst) times the theoretical prediction was obtained. 相似文献
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The nonlinear evolution of a Hamiltonian magnetic field line reconnection in a two-dimensional fluid plasma leads to a macroscopic equilibrium with a finite-size island and fine-scale spatial structures. The latter arise from the phase mixing of the Lagrangian invariant fields. This equilibrium is the analog of the Bernstein-Greene-Kruskal equilibrium solution for electrostatic Langmuir waves. 相似文献
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以4-氯-7-硝基苯并-2-氧杂-1,3-二唑、乙二胺和溴乙酸乙酯等为原料,合成4-氨基-7-硝基苯并-2-氧杂-1,3-二唑类衍生物(NBD-OEt),通过IR、NMR和MS对其进行结构表征。研究NBD-OEt的吸收光谱和荧光光谱性质,探讨其在H2O/EtOH(60/40, V/V) pH 7.40的HEPES缓冲体系中对Hg2 的响应,以及NBD-OEt与Hg2 的结合模式。结果表明, 随Hg2 的不断加入可诱使NBD-OEt在476nm的吸收峰红移至514nm,并有两个等吸收点(347nm、482nm);其荧光发射峰由536nm红移至559nm,且在525nm出现等发射点;通过Job plot法测定NBD-OEt与Hg2 以1:1的计量比结合。 相似文献
10.
The ultrasonic signals in long bones contain multiple guided modes which are mutual superposed.The velocities of guided waves in long bones are very sensitive to cortical thickness (CTh).In this paper,Hilbert-Huang transform(HHT) was proposed to analyze multi-mode guided waves,which can decompose superposed waves into many independent modes.Then the group velocity of each mode was obtained at corresponding frequency,which was compared with the results of short time Fourier transform(STFT).The CTh was also obtained by comparing with the theoretical calculation.The results showed that the experimental determined thickness was in agreement with the actual CTh,indicating that measuring the velocity of the guided mode can be used to estimate the CTh.The HHT is an effective method to identify multimode guided waves. 相似文献