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21.
基于荧光内滤效应的锂离子荧光化学传感器研究 总被引:1,自引:0,他引:1
报道了一种基于荧光内滤效应的荧光增强型锂离子光化学传感器,将荧光试剂、亲脂性pH指示剂和锂离子中性载体结合在增塑的PVC膜中,Li+与H+在膜相中的竞争萃取效应引起受亲脂性pH指示剂调制的敏感膜荧光值的变化.推导了有关理论关系式,研究了该传感器的响应特性,并对人工合成样品进行测试,结果较为满意. 相似文献
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23.
Negative Refraction and Near-Field Imaging of an Elliptical-Rod Photonic Crystal Slab in the Second Band 下载免费PDF全文
Negative refraction and imaging properties of the electromagnetic wave through a two-dimensional photonic crystal (PC) slab, which consists of a square lattice of elliptical dielectric rods immersed in the air background, is studied by the plane-wave expansion method and the finite-difference time-domain method. A point source placed in the vicinity of the PC slab can form a good-quality image spot through the PC slab for the incident frequencies within the second photonic band. The calculated result also shows that negative refraction occurs in this kind of PC slab. 相似文献
24.
The oxide formation on thin copper films deposited on Si wafer was studied by XPS, SEM and Sequential Electrochemical Reduction Analysis SERA. The surfaces were oxidized in air with a reflow oven as used in electronic assembly at temperatures of 100 °C, 155 °C, 200 °C, 230 °C and 260 °C. The SERA analyses detected only the formation of Cu2O but the XPS analysis done for the calibration of the SERA equipment proved also the presence of a CuO layer smaller than 2 nm above the Cu2O oxide. The oxide growth follows a power-law dependence on time within this temperature range and an activation energy of 33.1 kJ/mol was obtained. The wettability of these surfaces was also determined by measuring the contact angle between solder and copper substrate after the soldering process. A correlation between oxide thickness and wetting angle was established. It was found that the wetting is acceptable only when the oxide thickness is smaller than 16 nm. An activation energy of 27 kJ/mol was acquired for the spreading of lead free solder on oxidized copper surfaces.From wetting tests on copper surfaces protected by Organic Solderability Preservatives (OSP), it was possible to calculate the activation energy for the thermal decomposition of these protective layers. 相似文献
25.
水下光通信充分利用了海水对激光的衰减窗口效应,具有隐蔽、安全、非接触和快速机动等特性,兼具无线通信和光纤通信的优点,其关键技术在于光收发端机的研制;PPM(Pulse Position Modulation)数字脉冲位置调制具有低平均功率和高峰值功率等特性,特别适合用于无线数字光通信。两者性能的融合需要高灵敏度数字光接收机的实现。利用阵列光电检测接收、高速A/D转换和信号处理等相关技术,采用DSP处理器,高灵敏度的数字光PPM接收机得以实现,实验和测试表明它大大降低了接收机对于整个系统信噪比的要求,获得了较好的性能。 相似文献
26.
Carla Ruggiero Stefania Ramirez Eric Ramazzotti Rita Mancini Roberto Muratori Maria Augusta Raggi Matteo Conti 《Journal of separation science》2020,43(8):1440-1449
In this work, a convenient method for the therapeutic monitoring of seven common antipsychotic drugs in “dried plasma spot” samples has been developed. It is based on the liquid chromatography tandem mass spectrometry technique, operating in multiple reaction monitoring mode, and a straightforward procedure for the simultaneous extraction of all antipsychotics in a single step, with high extraction yield. The method was fully validated with proper accuracy, precision, selectivity and sensitivity, for all the drugs. Limits of quantification were 0.12, 1.09, 1.46, 1.47, 5.70, 1.32, 1.33 µg/L for haloperidol, aripiprazole, olanzapine, quetiapine, clozapine, risperidone, and paliperidone, respectively. Accuracy, intra‐ and interday precision values were <10% for all drugs at all concentration levels examined. The method was tested in the analysis of 30 plasma samples from real patients for each drug. The proposed analytical approach, by combining practical and logistical advantages of microsampling with liquid chromatography tandem mass spectrometry analytical performance, could offer an ideal strategy for accurate and timely therapeutic drug monitoring of antipsychotic drugs in most clinical settings, even in remote centers and/or in out‐patient settings, bringing so many potential improvements in psychiatric patient care. 相似文献
27.
采用修正的扭曲波玻恩近似(DWBA)方法,本文计算了共面对称几何条件下电子碰撞Mg(3s2) 原子(e,2e)反应的三重微分截面.理论方法通过引入Gamow因子来表示(e,2e)反应的后碰撞相互作用(PCI).将计算结果与实验结果及标准DWBA计算结果进行了比较,发现PCI效应起着重要的作用. 相似文献
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29.
Braulio Aranda Sergio A. Moya Andres Vega Gonzalo Valdebenito Sofia Ramirez‐Lopez Pedro Aguirre 《应用有机金属化学》2019,33(4)
Aminocarbonylation of aryl halides, homogeneously catalysed by palladium, is an efficient method that can be employed for obtaining amides for pharmaceutical and synthetic applications. In this work, palladium (II) complexes containing P^N ligands were studied as catalysts in the aminocarbonylation of iodobenzene in the presence of diethylamine. Two types of systems were used: a palladium (II) complex formed in situ; and one prepared prior to the catalytic reaction. In general, the palladium complexes studied achieved high conversions in an average reaction time of less than 2 hr, which is less than that for the standard system (Pd (II)/PPh3) used. The pre‐synthesized complexes were faster than their in situ counterparts, as the latter require an induction time to form the Pd/P^N species. The structure and electronic properties of the ligand P^N can influence both the activity and the selectivity of the reaction, stabilizing the acyl‐palladium intermediates formed in a better manner. 相似文献
30.
(1S、2R、3R、5R、7aR)-1,2-Dihydroxy-3-hydroxy methyl-5-methylpyrrolizidine(hyacinthacine A6, I) was synthesized by Wittig's methodology via the reaction of aldehyde 6, prepared from the partially protected derivative of polyhydroxylated pyrrolidine, with appropriated ylides, followed by cyclization through the intemal reductive amination process of the resulting a,B-unsaturated ketone 7, and total deprotection. 相似文献