基于区间解析冗余关系的参数不确定性研究

本文主要目的是拓展基于区间解析冗余关系法I-ARRs(Interval valued Analytical Redundancy Relations)对不确定性混杂系统的故障检测。该方法产生一组对故障估计的阈值,一旦标称残差超过阈值,则故障能被检测。现有的故障检测方法主要是针对参数性故障,因此对测量信号导数的估计呈现出各种限制。而且在I-ARRs中对测量信号导数十分敏感,这不可避免地涉及到对残差的估计。为解决这一问题,利用鲁棒滑模微分器方法得到对含噪声测量信号导数最优估计,降低残差噪声,以减小虚警、漏报,从而提高鲁棒性。通过典型电力电子电路BUCK电路仿真,验证了此方法的有效性。     

基于双重自注意力机制的人脸图像修复

人脸图像修复旨在修复输入人脸图像中的缺失区域,生成令人满意的高质量修复结果.然而当存在大面积缺失时,直接修复缺失人脸图像十分困难,此时修复网络的全局上下文信息感知能力是影响修复结果的关键.鉴于此,本文提出了软硬注意力相结合的双重自注意力模块.该模块通过全局相似度计算来获得软硬两种注意力特征,之后对两种注意力特征进行自适应融合,进而提高修复网络对全局上下文信息的感知能力.此外,本文进一步提出了多尺度生成对抗网络以加强对修复结果的监督,促使修复网络生成更高质量的修复结果.实验结果表明,本文方法在定量和定性评测上均优于五种先进的对比方法.     

Electrochemical "signal-on" reporter for amyloid aggregates

The synthesis and characterization of four new Ferrocene (Fc) bioconjugates, bearing a podant (Lys)-Leu-Val-Phe-Phe motif, namely the hydrophobic sequence of amyloid-β-peptides (Aβ), is reported. The Fc-peptide conjugates are characterized by a reversible redox activity and the ability to undergo hydrophobic and hydrogen bonding interactions. Biomolecular interactions between Fc-bioconjugates with Aβ(12-28) fragments were studied by circular dichroism (CD), transmission electron microscopy (TEM), and electrochemistry. All four Fc-peptides interacted favourable with Aβ(12-28) and prevented fibril formation, the extent of which depended on the length of the peptide and the nature of the C-terminal group. The aggregates obtained for the Aβ(12-28)/Fc-peptide mixtures range from short fibrils to spherical aggregates. We demonstrated that in solution the peptide sequence and peptide charge affect the biomolecular interactions. Fc-peptide interactions with immobilized Aβ(12-28)-Cys films on Au surfaces were detected by measuring the current response of the Fc redox process. The formal redox potential, E(0), at ~440 (10) mV and i(pc)/i(pa) at 0.9 were observed characteristic for the monosubstituted Fc-derivative undergoing a one-electron redox process. On the surface, methyl ester-protected Fc-peptides (1 and 3) interacted only weakly with Aβ(12-28)-Cys films, giving rise to minimal redox activity. In contrast, charged Fc-peptides (2 and 4) gave a significant electrochemical readout following the interaction with Aβ(12-28)-Cys films. Interestingly, the Fc-peptide charge dictates the surface-assisted interactions, while hydrophobic and ionic effects contribute to the overall solution behaviour of the Fc-bioconjugates with Aβ(12-28).     

Impact of Single Basepair Mismatches on Electron‐Transfer Processes at Fc‐PNA⋅DNA Modified Gold Surfaces

Gold‐surface grafted peptide nucleic acid (PNA) strands, which carry a redox‐active ferrocene tag, present unique tools to electrochemically investigate their mechanical bending elasticity based on the kinetics of electron‐transfer (ET) processes. A comparative study of the mechanical bending properties and the thermodynamic stability of a series of 12‐mer Fc‐PNA?DNA duplexes was carried out. A single basepair mismatch was integrated at all possible strand positions to provide nanoscopic insights into the physicochemical changes provoked by the presence of a single basepair mismatch with regard to its position within the strand. The ET processes at single mismatch Fc‐PNA?DNA modified surfaces were found to proceed with increasing diffusion limitation and decreasing standard ET rate constants k⁰ when the single basepair mismatch was dislocated along the strand towards its free‐dangling Fc‐modified end. The observed ET characteristics are considered to be due to a punctual increase in the strand elasticity at the mismatch position. The kinetic mismatch discrimination with respect to the fully‐complementary duplex presents a basis for an electrochemical DNA sensing strategy based on the Fc‐PNA?DNA bending dynamics for loosely packed monolayers. In a general sense, the strand elasticity presents a further physicochemical property which is affected by a single basepair mismatch which may possibly be used as a basis for future DNA sensing concepts for the specific detection of single basepair mismatches.     

Multisubband transport and magnetic deflection of Fermi electron trajectories in three terminal junctions and rings

We study the electron transport in three terminal junctions and quantum rings looking for the classical deflection of electron trajectories in the presence of intersubband scattering. We indicate that although the Aharonov-Bohm oscillations and the Lorentz force effects co-exist in the low subband transport, for higher Fermi energies a simultaneous observation of both effects is difficult and calls for carefully formed structures. In particular, in quantum rings with channels wider than the input lead the Lorentz force is well resolved but the Aharonov-Bohm periodicity is lost in chaotic scattering events. In quantum rings with equal lengths of the channels and T-shaped junctions the Aharonov-Bohm oscillations are distinctly periodic but the Lorentz force effects are not well pronounced. We find that systems with wedge-shaped junctions allow for observation of both the periodic Aharonov-Bohm oscillations and the magnetic deflection.     

Tuning the plasmon energy of palladium-hydrogen systems by varying the hydrogen concentration

First-principles calculations are performed to obtain the dielectric function and loss spectra of bulk PdH(x). Hydrogen concentrations between x = 0 and 1 are considered. The calculated spectra are dominated by a broad peak that redshifts in energy with x. The obtained bulk dielectric function is employed to compute the loss spectra of PdH(x) spherical nanoparticles as a function of x. The dominant plasmon peak in the spherical nanoparticle is lowered in energy with respect to the bulk case. However, the dependence of the resonance energy on the hydrogen concentration is roughly similar to that in bulk.