scholarly journals A Theoretical Analysis of Coherent Cross-Peaks in Polarization Selective 2DIR for Detection of Cross-α Fibrils

2021 ◽  
Author(s):  
Dean Edun ◽  
Olivia Cracchiolo ◽  
Arnaldo Serrano
Keyword(s):  
Theoretical Analysis ◽  
Structural Information ◽  
Broad Band ◽  
Vibrational Modes ◽  
The Cross ◽  
Fibril Length ◽  
2D Data ◽  
Excitonic States ◽  
Peptide Fibrils ◽  
Exciton Scattering

The coupled amide-I vibrational modes in peptide systems such as fibrillar aggregates can often provide a wealth of structural information, though the associated spectra can be difficult to interpret. Using exciton scattering calculations, we characterized the polarization selective 2DIR peak patterns for cross-α peptide fibrils, a challenging system given the similarity between the monomeric and fibrillar structures, and interpret the results in light of recently collected 2D data on the cross-α peptide PSMα3. We find that stacking of α-helices into fibrils couples the bright modes across helical subunits, generating three new Bloch-like extended excitonic states that we designate A⏊, E∥, and E⏊. Coherent superpositions of these states in broad-band 2DIR simulations lead to characteristic signals that are sensitive to fibril length, and match the experimental 2DIR spectra.

scholarly journals Phonons in Short-Period GaN/AlN Superlattices: Group-Theoretical Analysis, Ab initio Calculations, and Raman Spectra

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 286
Author(s):  
Valery Davydov ◽  
Evgenii Roginskii ◽  
Yuri Kitaev ◽  
Alexander Smirnov ◽  
Ilya Eliseyev ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Density Functional ◽  
Structural Characteristics ◽  
Vibrational Modes ◽  
Phonon Modes ◽  
Short Period ◽  
Group Theoretical Analysis

We report the results of experimental and theoretical studies of phonon modes in GaN/AlN superlattices (SLs) with a period of several atomic layers, grown by submonolayer digital plasma-assisted molecular-beam epitaxy, which have a great potential for use in quantum and stress engineering. Using detailed group-theoretical analysis, the genesis of the SL vibrational modes from the modes of bulk AlN and GaN crystals is established. Ab initio calculations in the framework of the density functional theory, aimed at studying the phonon states, are performed for SLs with both equal and unequal layer thicknesses. The frequencies of the vibrational modes are calculated, and atomic displacement patterns are obtained. Raman spectra are calculated and compared with the experimental ones. The results of the ab initio calculations are in good agreement with the experimental Raman spectra and the results of the group-theoretical analysis. As a result of comprehensive studies, the correlations between the parameters of acoustic and optical phonons and the structure of SLs are obtained. This opens up new possibilities for the analysis of the structural characteristics of short-period GaN/AlN SLs using Raman spectroscopy. The results obtained can be used to optimize the growth technologies aimed to form structurally perfect short-period GaN/AlN SLs.

DFCWs Design Based on Improved DPSO

2013 ◽  
Vol 333-335 ◽  
pp. 623-627
Author(s):  
Jing Jun Li ◽  
Yong Hua Jiang ◽  
Bo Dan ◽  
Wei Wei Gao
Keyword(s):  
Theoretical Analysis ◽  
Cross Correlation ◽  
Correlation Energy ◽  
Code Length ◽  
Discrete Particle ◽  
Frequency Coding ◽  
Simulation Results ◽  
The Cross ◽  
The Cost ◽  
Correlation Level

Orthogonal discrete frequency coding waveforms(DFCWs) is an ideal quasi-orthogonal waveform. This paper analyses the ambiguity function of DFCWs and the results indicate that the correlation characteristics of DFCWs have only relationship with the code length and coding order. Based on the theoretical analysis, we defined the cross-correlation energy as the cost function, and used the improved discrete particle swarmoptimization(DPSO) to optimize the order of DFCWs. The new signal can effectively restrain the cross-correlation level between the two DFCWs. Simulation results verify the effectiveness of the designed DFCWs.

Cross-Media Retrieval Based on Query Modality and Semi-Supervised Regularization

2017 ◽  
Vol 21 (7) ◽  
pp. 1211-1220
Author(s):  
Yihe Liu ◽  
◽  
Huaxiang Zhang ◽  
Li Liu ◽  
Lili Meng ◽  
...  
Keyword(s):  
Semantic Information ◽  
Structural Information ◽  
Unlabeled Data ◽  
Experimental Results ◽  
Retrieval Method ◽  
Cross Media ◽  
Feature Spaces ◽  
Media Objects ◽  
The Cross ◽  
Original Feature

Existing cross-media retrieval methods usually learn one same latent subspace for different retrieval tasks, which can only achieve a suboptimal retrieval. In this paper, we propose a novel cross-media retrieval method based on Query Modality and Semi-supervised Regularization (QMSR). Taking the cross-media retrieval between images and texts for example, QMSR learns two couples of mappings for different retrieval tasks (i.e. using images to search texts (Im2Te) or using texts to search images (Te2Im)) instead of learning one couple of mappings. QMSR learns two couples of projections by optimizing the correlation between images and texts and the semantic information of query modality (image or text), and integrates together the semi-supervised regularization, the structural information among both labeled and unlabeled data of query modality to transform different media objects from original feature spaces into two different isomorphic subspaces (Im2Te common subspace and Te2Im common subspace). Experimental results show the effectiveness of the proposed method.

Reflections on the UNCRC’s Future from a Transdisciplinary Bricoleur

2013 ◽  
Vol 21 (3) ◽  
pp. 510-522 ◽  
Author(s):  
Richard C. Mitchell
Keyword(s):  
Theoretical Analysis ◽  
Lived Experiences ◽  
Final Section ◽  
Growing Season ◽  
Wine Industry ◽  
Agricultural Workers ◽  
Local Application ◽  
The Cross ◽  
Methodological Reflection

The paper argues two main points. First, there remain vast untapped potentials for implementing children’s rights within both present and coming generations, and second, that transdisciplinary theorising and local application can create and exploit such new opportunities. The paper begins with a theoretical analysis of the cross-cutting nature of the UNCRC, and its continued civilising impact as part of the globalised ‘rights revolutions’ reported by controversial Harvard psychologist Steven Pinker (2011: 378-481). I then move to a methodological reflection on how the treaty might be applied as a bricoleur in the lived experiences of children, families, caregivers and communities. The final section outlines a case study from the grape and wine industry located within the Niagara Region of Canada that applied these theoretical and methodological resources as a form of critical praxis in the lives of migrant agricultural workers temporarily employed there through the growing season year after year.

The Settlement Analysis and Reinforcement of a Cast-In Situ Concrete Floor

2011 ◽  
Vol 243-249 ◽  
pp. 5523-5526
Author(s):  
Hua Wei Zhao ◽  
Hong Ping Zhu ◽  
Ya Hong Ding
Keyword(s):  
Carbon Fiber ◽  
Theoretical Analysis ◽  
Load Transfer ◽  
Maximum Settlement ◽  
Concrete Floor ◽  
Comparative Analyses ◽  
Maximum Crack ◽  
The Cross ◽  
Settlement Analysis

After form a removal concrete cross ribbed beam floor in a commercial plaza, the vertical cracks are discovered, and the settlement analysis and reinforcement of a Cast-in-situ concrete floor are performed. The detection of the maximum crack is 0.3mm,and the Maximum settlement of cross ribbed beam is 48mm. By theoretical analysis, improper form removal during construction stage makes the actual floor force inconsistent with the design of a load transfer, which is the main reason of the excessive settlement in the cross ribbed beam. Through the economy, ease of handling in construction and other aspects of comparative analyses, the close beam side by epoxy grout and paste the carbon fiber under the beam to reinforce the cross ribbed beam. After reinforcement, no defect is discovered in the project so far.

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