scholarly journals Quo Vadis Nonlinear Optics? An Alternative and Simple Approach to Third Rank Tensors in Semiconductors

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 127
Author(s):  
Hendradi Hardhienata ◽  
Salim Faci ◽  
Adalberto Alejo-Molina ◽  
Mohammad Ryan Priatama ◽  
Husin Alatas ◽  
...  

It is well understood that nonlinear optical (NLO) phenomena are deeply related to the material’s symmetry. Mathematically, the material symmetry can be described in terms of the nonzero parameters in the nonlinear susceptibility tensors. Generally, more complex structures involve more nonzero parameters in the tensor. The number of parameters increases rapidly if higher NLO orders are considered, complicating the physical analysis. Conventionally, these parameters are obtained via abstract symmetry analysis, e.g., group theory (GT). This work presents a novel theoretical analysis to approach the nonlinear tensor using the simplified bond hyperpolarizability model (SBHM) and compare it with GT. Our analysis is based on a light–matter interaction classical phenomenological physical framework. Rather than just looking at the symmetry of the crystal, the model applies physical considerations requiring fewer independent parameters in the tensor than GT. Such a simplification significantly improves the determination of the surface–bulk SHG contribution factors, which cannot be extracted from the experiment alone. We also show for the case of perovskite that the SHG contribution can be addressed solely from their surface dipoles with only one independent component in the tensor. Therefore, this work may open the path for a similar analysis in other complicated semiconductor surfaces and structures in the future, with potential applications to nanoscale surface characterization and real-time surface deposition monitoring.

The Analyst ◽  
2015 ◽  
Vol 140 (6) ◽  
pp. 1772-1786 ◽  
Author(s):  
Zhi Guo ◽  
Guiqiu Chen ◽  
Guangming Zeng ◽  
Zhongwu Li ◽  
Anwei Chen ◽  
...  

The development of H2S fluorescence-sensing strategies and their potential applications in the determination of sulfate-reducing bacteria activity.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1040
Author(s):  
Asuka Shirakawa ◽  
Yoshiyuki Manabe ◽  
Koichi Fukase

Asparagine-linked N-glycans on proteins have diverse structures, and their functions vary according to their structures. In recent years, it has become possible to obtain high quantities of N-glycans via isolation and chemical/enzymatic/chemoenzymatic synthesis. This has allowed for progress in the elucidation of N-glycan functions at the molecular level. Interaction analyses with lectins by glycan arrays or nuclear magnetic resonance (NMR) using various N-glycans have revealed the molecular basis for the recognition of complex structures of N-glycans. Preparation of proteins modified with homogeneous N-glycans revealed the influence of N-glycan modifications on protein functions. Furthermore, N-glycans have potential applications in drug development. This review discusses recent advances in the chemical biology of N-glycans.


ChemInform ◽  
2010 ◽  
Vol 24 (2) ◽  
pp. no-no
Author(s):  
R. E. MORRIS ◽  
W. T. A. HARRISON ◽  
J. M. NICOL ◽  
A. P. WILKINSON ◽  
A. K. CHEETHAM

2021 ◽  
Author(s):  
Thomas Theurer ◽  
David Muirhead ◽  
David Jolley ◽  
Dmitri Mauquoy

<p>Raman spectroscopy represents a novel methodology of characterising plant-fire interactions through geological history, with enormous potential. Applications of Raman spectroscopy to charcoal have shown that this is an effective method of understanding intensity changes across palaeofire regimes. Such analyses have relied on the determination of appropriate Raman parameters, given their relationship with temperature of formation and microstructural changes in reference charcoals. Quantitative assessments of charcoal microstructure have also been successfully applied to the assessment of carbonaceous maturation under alternate thermal regimes, such as pyroclastic volcanism. Palaeowildfire systems in association with volcanism may present a complex history of thermal maturation, given interactions between detrital charcoals and volcanogenic deposition. However, whilst palaeofire and volcanic maturation of carbonaceous material are well understood individually, their interaction has yet to be characterised. Here we present the first analysis of palaeofire charcoals derived from volcanic ignition utilising Raman spectroscopy. Our results indicate that complex interactions between volcanism and palaeofire systems may be better understood by the characterisation of charcoal microstructure, alongside palaeobotanical and ecosystem studies. Understanding the unique relationship between wildfires and volcanism, and the impact that this has on the fossil record, may better assist our understanding of wildfire systems in deep history. Further still, this highlights the potential for better understanding the socioecological impacts of modern and future wildfire systems closely associated with volcanic centres. </p>


Metrologia ◽  
2017 ◽  
Vol 54 (5) ◽  
pp. 653-662 ◽  
Author(s):  
Matthias Müller ◽  
Burkhard Beckhoff ◽  
Edyta Beyer ◽  
Erik Darlatt ◽  
Rolf Fliegauf ◽  
...  

2006 ◽  
Vol 324-325 ◽  
pp. 787-792
Author(s):  
Boris Aberšek ◽  
Jože Flašker ◽  
Srečko Glodež

For accurate determination of the service life we must take into account the loading, which are in most cases random loading of variable amplitude, the geometry and material properties of construction elements which are known not to be constants. The more precise these input parameters are modeled; the more precise and reliable are the results. In our paper we will deal in detail with the model of crack initiation and propagation in the complex structures as a basis of the algorithm for calculating the service life. For determination of the service life for the area of short cracks we used Bilby, Cottrell and Swinden model which is based on the theory of continuously distributed dislocations and we complemented it with random generation of structure of material before cracks. For the long crack we have developed a stochastic model for determination of service life.


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