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131.
Based on the equilibrium structures from quantum mechanics AM1 method, employing INDO/CI method and the sum-over-state (SOS) formula, the one-photon absorption (OPA) and two-photon absorption (TPA) properties as well as the second hyperpolarizabilities were discussed in detail for a kind of PPV derivative poly 2-(9-phenylanthracen-10-yl)-1,4-phenylenevinylene (P1). The results indicate that the two-photon cross section (3) increases with the increasing of the number of repeating segment (n), however only a slight increase corresponds to the increasing of molecular weight when the repeating unit number arrives at a certain number. From this point of view, the TPA cross section values of P1 were extrapolated through the linear fit of 3 value vs. 1/n. The δ value of P1 is as high as 181 GM (1 GM=10^-50 cm^4·s·photon^-1). Concerning the influence of pendent group and extension of π-conjugation on 3 values, another four oligomers P2, PPV, P1-1, and P2-1 were investigated for comparison. The calculation results reveal that the position and property of pendent group have great influence on the OPA and TPA properties. A most crucial role for relatively larger 3 value was played by the extension of π-conjugation. 相似文献
132.
本文利用金属有机化合物化学气相沉积(MOCVD)技术在(001)面图形化蓝宝石衬底(PSS)上生长了一种含有AlGaN-InGaN/GaN MQWs (multiple quantum wells)-AlGaN双势垒结构的高In组分太阳能电池外延材料。高分辨率X射线衍射(HRXRD)和光致发光(PL)谱分析表明,与含有AlGaN电子阻挡层的低In组分的量子阱结构太阳能电池外延材料相比,该结构材料具有较小的半峰全宽(FWHM),计算表明:此结构材料的位错密度降低了一个数量级,达到107 cm-2;同时,有源区中的应变弛豫降低了51%;此外,此结构材料的发光强度增强了35%。研究结果表明含有AlGaN双势垒结构的外延材料可以减小有源区的位错密度,降低非辐射复合中心的数目,增大有源区有效光生载流子的数目,为制备高质量太阳能电池提供实验依据。 相似文献
133.
GUO Yi-Qing ZHANG Xue-Yao ZHANG Jian-Li HU Hong-Bo ZHA Min HE Hui-Hai FENG Zhao-Yang WU Chao-Yong WANG Bo ZHANG Yi A.Surdo LU Hong 《中国物理C(英文版)》2010,34(5)
'G4argo', a GEANT4-based simulation package for the ARGO-YBJ detector, is described in this paper. G4argo incorporates in the simulation the true RPC time resolution and another 0.5 ns time uncertainty which is introduced from the offline calibration of TDC. In addition, the correct RPC geometry and the true materials for the ARGO-YBJ experimental hall are implemented. As a result, G4argo simulation shows a very good agreement with real data. 相似文献
134.
135.
Xin Lu Jia Xu Yulin Wang Yadong Xue Juan Li Xiaoya Hu Zhanjun Yang 《Electroanalysis》2022,34(2):332-337
Nitrogen-doped TiO2 nanocrystals (N−TiO2 NCs) were simply synthesized and then functionalized with streptavidin for highly sensitive electrochemical immunoassay of tumor marker. Scanning electron microscopy, transmission electron microscopy, static water contact angle, and cyclic voltametric measurement were adapted to examine the properties of N−TiO2 NCs and resultant immunosensor. The functionalized N−TiO2 NCs sensing platform shows high electrochemical conductivity, large surface area and excellent hydrophilicity. The features make them to produce high current response, capture more antibody molecules, and maintain the bioactivity of immobilized antibodies. By means of carcinoembryonic antigen (CEA) as model tumor marker, a wide linear range of 0.005–3 ng/mL and a low detection limit of 0.005 ng/mL (signal-to-noise ratio of 3) were achieved by the proposed CEA immunosensor. Furthermore, the resultant CEA immunosensor displays high specificity and was employed to determine CEA in clinical serum samples. 相似文献
136.
137.
A novel and reliable direct electrochemical method was established for the detection of adenine, based on the differential
pulse anodic stripping response at a poly(amidosulfonic acid) (poly-ASA)-modified glassy carbon electrode (GCE) fabricated
by electropolymerization. The characterization of electrochemically synthesized poly-ASA film was investigated by atomic force
microscopy, electrochemical impedance spectroscopy, and voltammetric methods. This poly-ASA-modified GCE could greatly enhance
the detection sensitivity of adenine. At optimum conditions, the anodic peak exhibits a good linear concentration dependence
in the range from 3.0 × 10−8 to 1.0 × 10−6 M (r = 0.9994). The detection limit is 8.0 × 10−9 M (S/N = 3). The proposed method could be used to determinate the adenine in tablets of vitamin B4 with satisfactory results. 相似文献
138.
We propose a locking-free nonconforming finite element method to solve for the displacement variation in the pure displacement boundary value problem of planar linear elasticity. The method proposed in this paper is robust and optimal, in the sense that the convergence estimate in the energy is independent of the Lamé Parameter λ. 相似文献
139.
A new ultraviolet (UV) labeling reagent, p-acetamidobenzenesulfonyl fluoride (PAABS-F), was designed and synthesized to label and determine the amino acids by capillary electrophoresis (CE) with diode-array detector (DAD). PAABS-F is very stable and easy to synthesize. It reacted with primary or secondary amino acids very quickly under facile conditions to give corresponding derivatives in high yield with excellent sensitivity and stability. No by-products were observed in amino acid derivatives when stored at room temperature under natural daylight for at least 7 days. Both amino acids standard solution and real samples reacted with this new UV labeling reagent smoothly to form high UV-absorption derivatives. The labeled 20 standard amino acids were efficiently separated by CE and the mass detection limits (S/N = 3) were ranged from 59.3 fmol for l-tryptophan to 1.70 pmol for l-histidine. 相似文献
140.
In this paper, we study two kinds of first-order singular discrete systems. By the fixed point index theory, we investigate the existence and multiplicity of positive periodic solutions of the systems. 相似文献