A new approach to the symmetric rectangular quantum well: Analytic determination of well width from energy levels

1994 ◽  
Vol 62 (6) ◽  
pp. 564-565 ◽  
Author(s):  
C. Fouillant ◽  
C. Alibert

This paper studies a quantum well heterostructure made up by a zinc oxide (ZnO) thin layer (well) sandwiched between two Zn1-xMgxO layers acting as potential barriers. Setting the width of the well to a = 10 nm, the allowed quantum states in the conduction band (CB) and the wave function profiles are examined for two values of magnesium concentration : x = 0.1 and x = 0.2. The calculated wavelengths corresponding to intra-band transitions in the conduction band are in the infrared domain of the electromagnetic spectrum. These wavelengths depend on x, allowing to control the optoelectronic properties of the quantum well by adjusting the concentration x during the growth process.


2020 ◽  
Vol 9 ◽  
pp. 210
Author(s):  
M. E. Grypeos ◽  
Th. E. Liolios

A new approach is proposed on the basis of the quantum mechanical hypervirial theorems technique for the approximate analytic (or semi-analytic) determination of bound state energy eigenfunctions for quite a wide class of central potentials. The accuracy of the method is tested for the Gaussian potential and is best for the ground state.


2017 ◽  
Vol 30 (1) ◽  
pp. 273-289
Author(s):  
Anmari Meerkotter

The Constitutional Court (CC) judgment of Lee v Minister of Correction Services 2013 2SA 144 (CC) is a recent contribution to transformative constitutional jurisprudence in the field of the law of delict. This matter turned on the issue of factual causation in the context of wrongful and negligent systemic omissions by the state. In this case note, I explore the law relating to this element of delictual liability with specific regard to the traditional test for factual causation – the conditio sine qua non (‘but-for’) test. In particular, I note the problems occasioned by formalistic adherence to this test in the context of systemic state omissions as evidenced by the SCA judgment in the same matter. I also consider the manner in which English courts have addressed this problem. Thereafter, I analyse the CC’s broader approach to the determination of factual causation as one based on common sense and justice. I argue that this approach endorses a break from a formalistic application of the test and constitutes a step towards an approach which resonates with the foundational constitutional values of freedom, dignity and equality. Furthermore, it presents an appropriate solution to the problems associated with factual causation where systemic omissions are concerned. I then consider the transformative impact of the Lee judgment. In particular, I argue that the broader enquiry favoured by the CC facilitates the realisation of constitutionally guaranteed state accountability, and amounts to an extension of the existing norm of accountability jurisprudence. Hence, I contend that the judgment presents a further effort by the Constitutional Court to effect wholesale the constitutionalisation of the law of delict, as well as a vindicatory tool to be used by litigants who have been adversely affected by systemic state omissions.


Author(s):  
Romain Desplats ◽  
Timothee Dargnies ◽  
Jean-Christophe Courrege ◽  
Philippe Perdu ◽  
Jean-Louis Noullet

Abstract Focused Ion Beam (FIB) tools are widely used for Integrated Circuit (IC) debug and repair. With the increasing density of recent semiconductor devices, FIB operations are increasingly challenged, requiring access through 4 or more metal layers to reach a metal line of interest. In some cases, accessibility from the front side, through these metal layers, is so limited that backside FIB operations appear to be the most appropriate approach. The questions to be resolved before starting frontside or backside FIB operations on a device are: 1. Is it do-able, are the metal lines accessible? 2. What is the optimal positioning (e.g. accessing a metal 2 line is much faster and easier than digging down to a metal 6 line)? (for the backside) 3. What risk, time and cost are involved in FIB operations? In this paper, we will present a new approach, which allows the FIB user or designer to calculate the optimal FIB operation for debug and IC repair. It automatically selects the fastest and easiest milling and deposition FIB operations.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1411
Author(s):  
Rashida Perveen ◽  
Xiukang Wang ◽  
Yasir Jamil ◽  
Qasim Ali ◽  
Shafaqat Ali ◽  
...  

The present investigation was undertaken to assess the effects of different doses (100, 300, and 500 mJ) of low power He–Ne laser (632.8 nm) irradiation on seed germination and thermodynamics attributes and activities of potential germinating enzymes in relation with changes in seed metabolites. He–Ne laser seed irradiation increased the amylase (Amy), protease (Pro) and glucosidase (Gluco) activities, with a significant improvement in seed thermodynamics and seed germination attributes. A fast increase was found in free fatty acids (FFA), free amino acids (FAA), chlorophyll (Chl), carotenoids (Car), total soluble sugars (TSS) and reducing sugars (RS) in laser treated seeds in parallel with fast decline in seed oil contents and total soluble proteins (TSP). Significant positive correlations were recorded in laser-induced enhanced seed energy levels, germination, activities of germination enzymes with levels of FAA, FFA, Chl, TSS and RS, but a negative correlation with the levels of TSP and oil. In conclusion, the seed treatment with 100 and 300 mJ He–Ne laser was more effective to improve the seed germination potential associated with an improvement in seed energy levels due to increased activities of germination enzymes due to the speedy breakdown of seed reserves to simple metabolites as building blocks.


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