The electrochemical behavior of calcein (CA) has been investigated by using a conductive carbon black paste electrode (CCBPE) as working electrode. It exhibits a single well‐defined redox peak in phosphate buffered saline in the range of pH 5.5–8.0, which attributes to the irreversible oxidation with 2 electrons and 2 protons participation. Under the optimized analytical conditions, the proposed linear sweep voltammetry (LSV) method allows the determination of CA in a linear concentration range of 0.64–9.60 µM, with a limit of detection of 0.32 µM. Further, the interaction between CA and DNA were studied by voltammetric and spectrometric methods. Both studies have shown that CA can bind to DNA by the intercalation binding mode. Under the present experimental condition, the binding constant β of CA and dsDNA is 1.10×107. Meanwhile, in the loop‐mediated isothermal amplification (LAMP) reaction mixture there is obvious interaction between CA and dsDNA, resulting in a nonignorable decrease of the indicating sensitivity. 相似文献
Single-crystalline TiO2 nanomaterials with controlled phase composition and morphology were synthesized by hydrothermal transformation of H-titanate nanotubes under different pH. Rutile rectangle nanorods with two four-side tapered tips were produced at pH of 0, whereas anatase nanoparticles with mainly of rhombic shape were obtained at pH from 2 to 7 and their average particle size increased with pH. The transformation mechanisms at different pH were discussed. The single-crystalline anatase nanoparticles obtained at pH of 2 had ca. 12 nm in average particle size, and the powder possessed as large as 112 m2/g specific surface areas; the conversion efficiency of the dye-sensitized solar cell based on the nanoparticles was increased by over 40% as compared with that of the cell based on P25. 相似文献
为了评估弹核碎裂反应在碳离子肿瘤治疗中产生的影响,中国科学院近代物理研究所建立了一套探测器系统用来测量相关反应产物。这套探测系统包括起始探测器、水靶系统、带电粒子鉴别系统和中子测量系统。利用中国科学院近代物理研究所250 MeV/u 12C6+ 束打50 mm水靶的实验在束测试了这套系统的性能。实验结果表明,通过ΔE-E 和TOF-ΔE 两种粒子鉴别方法这套探测系统清楚地区分了H,He,Li,Be,B和C 等元素。通过计算不同Z 值带电碎片的微分截面得到了这些带电碎片(本工作给出元素H 和He)相应的角分布。这套探测系统中的带电粒子测量系统性能达到了设计的预期目标。For estimating the influence of the projectile breakup reaction on carbon ion tumour therapy, a detector system was built by IMP(Institute of Modern Physics), Chinese Academy of Sciences(CAS), and used to detect the results of the reaction. The system is composed of start detector, water target system, charged fragments detector system and neutron detector system. The performance of the detector system was tested in the experiment of 5 cm thick water target bombarded by 250 MeV/u carbon beam. The results reveal that the charged fragments, such as elements H, He, Li, Be, B and C, were identified clearly by ΔE-E and ΔE-TOF techniques. The angular distributions of some charged fragments were obtained by calculating the charge-changing cross-sections of the fragments(e.g. elements H and He isotopes in our work). The test results prove that the charged fragment detector system achieves the design aim. 相似文献
A scheme for implementing secure communication based on chaotic maps and strong tracking filter (STF) is presented, and a modified STF algorithm with message estimation is developed for the special requirement of chaotic secure communication. At the emitter, the message symbol is modulated by chaotic mapping and is output through a nonlinear function. At the receiver, the driving signal is received and the message symbol is recovered dynamically by the STF with estimation of message symbol. Simulation results of Holmes map demonstrate that when message symbols are binary codes, STF can effectively recover the codes of the message from the noisy chaotic signals. Compared with the extended Kalman filter (EKF), STF has a lower bit error rate. 相似文献
Polymerization of norbornene has been conducted with [t‐BuNSiMe2(3,6‐t‐Bu2Flu)]TiMe2 ( 1 ) in toluene at 20 °C using modified methylaluminoxane that contained 0.4 mol‐% of triisobutylaluminium (TIBA) (dMMAO(0.4)) or 1.8 mol‐% of TIBA (dMMAO(1.8)). The 1 ‐dMMAO(0.4) catalytic system undergoes a living polymerization of norbornene. The catalysis of norbornene and propylene with the 1 ‐dMMAO(1.8) catalytic system gives markedly different results because of differences in transfer times of the polymers from Ti to TIBA. The successive addition of norbornene and propylene before the complete consumption of the norbornene in the 1 ‐dMMAO(1.8) system gives monodisperse PNB‐block‐poly(propylene‐ran‐norbornene)‐block‐PP terminated with a Ti–PP bond, which is exchanged with TIBA. Hence the repeated addition of the same amount of norbornene and propylene realizes the catalytic synthesis of monodisperse block copolymer in this system.