Cu-In and Cu-Zn-Sn Films as Precursors for Production of CuInSe2 and Cu2ZnSnSe4 Thin Films

2009 ◽  
Vol 1165 ◽  
Author(s):  
Olga Volobujeva ◽  
Enn Mellikov ◽  
Jaan Raudoja ◽  
Sergei Bereznev ◽  
Maris Pilvet

AbstractThe co-sputtered Cu-In precursor layers were characterized by bi-layer surface structure in which island-type crystals were formed in a small-crystalline matrix layer. The elemental composition of the island-type crystals corresponds to the compound CuIn2 and the matrix (area) consists of copper-rich Cu11In9 phase. The surface morphology of sequentially evaporated Cu-Zn-Sn precursor layers is determined by the deposition order of stacked consistent metal layers. Precursor Mo-Sn-Zn-Cu films exhibit a well-formed “mesa-like” structure of the surface in which larger crystals (about 1,5 μm) are located on a “small-crystalline” valley. For films with other sequences of metallic layers, the mesa like structure is not so well exposed and well formed flat precursor layers were produced replacing separate metallic Cu and Sn layers with Cu/Sn alloy layer. Selenization of both Cu-In and Cu-Zn-Sn precursor layers begins with the formation of binary Cu-selenides with compositions varying with the temperature. At temperatures higher than 3700C the selenization of Cu-In results in single-phase CuInSe2 films in contrast to the selenization of Sn-Zn-Cu films that results always in multi-phase films consisting of high quality Cu2ZnSnSe4 crystals and of separate small-crystalline phase of ZnSe.

1992 ◽  
Vol 06 (24) ◽  
pp. 1535-1540
Author(s):  
V. VIDYALAL ◽  
K. RAJASREE ◽  
C.P.G. VALLABHAN

Lead-doped Bi-2223 superconductors were prepared by two main popular solid state reaction routes, viz. solid state diffusion reaction and the matrix method. Even though both routes produce single-phase materials superconducting at 110 K, the resistivity behaviors above Tc are found to be different. Aging/degradation behavior was studied in terms of Tc on both sets of samples stored in a desiccator for eight months. Our studies indicate that the synthesising routes play a major role in the preparation of high quality bulk Pb-doped Bi-2223 superconductors which are more resistant to degradation when exposed to humid conditions.


2019 ◽  
Vol 59 (2) ◽  
pp. 153-161
Author(s):  
Daoud Ouamara ◽  
Frédéric Dubas ◽  
Sid Ali Randi ◽  
Mohamed Nadjib Benallal ◽  
Christophe Espanet

In this paper, a method to calculate the winding factor by only considering stator parameters without the rotor ones is developed. This is interesting because it allows the separation of the stator and rotor design, unlike the existing methods in the literature. A general method based on the matrix representation of a winding is presented. This approach requires the knowledge of four parameters : i) slots number, ii) phases number, iii) layers number, and iv) single-phase spatial distribution. A new feature of the multi-layer windings is introduced, it is called false-zero windings, which is divided into two categories: i) α-windings (i.e., odd false-zero windings), and ii) β-windings (i.e., even false-zero windings). The windings having no false-zero are categorized as γ-windings. The calculations are applied for single and multi-phase/-layer windings. The results of the comparison are satisfactory. The code used for the calculation is given in Appendix.


Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.


2006 ◽  
Vol 519-521 ◽  
pp. 71-78 ◽  
Author(s):  
J. David Embury ◽  
Warren J. Poole ◽  
David J. Lloyd

The process of work hardening in aluminum alloys is important from the viewpoint of formability and the prediction of the properties of highly deformed products. However the complexity of the strengthening mechanisms in these materials means that one must carefully consider the interaction of dislocations with the detailed elements of the microstructure and the related influence of the elements on dislocation accumulation and dynamic recovery. In addition, it is necessary to consider the influence of the work hardening process at various levels of plastic strain. This permits the possibility of designing microstructure for tailored plastic response, e.g. not simply designed for yield strength but also considering uniform elongation, spring-back, ductility etc. This presentation will explore the concept of identifying the various interactions which govern the evolution of the work hardening and their possible role in alloy design.


Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Abdulaziz Al Sultan ◽  
Ericka Teleg ◽  
MacKenzie Horn ◽  
Piyush Ojha ◽  
Linda Kasickova ◽  
...  

Background: CTA spot sign is a predictor of intracerebral hemorrhage (ICH) expansion. This sign can fluctuate in appearance, volume, and timing. Multiphase CTA (mCTA) can identify spot sign through 3 time-resolved images. We sought to identify a novel predictor of follow up total hematoma expansion using mCTA. Methods: This cohort study included patients with ICH between 2012-2019. Quantomo software was used to measure total hematoma volume (ml) from baseline CT & follow-up CT/MRI blinded to spot sign in 3 mCTA phases. Spot sign expansion was calculated by subtracting 1 st phase spot sign volume from 2 nd phase spot sign volume measured in microliters. Results: 199 patients [63% male, mean age 69 years, median NIHSS 11, IQR 6-20] were included. Median baseline ICH volume was 16.1 ml (IQR 5-29.9 ml). Amongst all three mCTA phases, spot sign was best detected on the 2nd phase (23% vs 17.5% 1 st phase vs 22% 3 rd phase). In multivariable regression, spot sign expansion was significantly associated with follow up total hematoma expansion (OR: 1.03 per microliter of spot sign expansion, p=0.01). Figure 1 shows the predicted total hematoma expansion by spot sign expansion. mCTA spot sign had a higher sensitivity for predicting total hematoma volume expansion than single-phase CTA (reported in meta-analysis of 14 studies), 86% vs 53%, respectively, while both having similar specificity, 87% vs 88%, respectively. Conclusion: Spot sign expansion on mCTA is a novel predictor of total hematoma expansion and could be used to select patients for immediate therapeutic intervention in future clinical trials. Using mCTA improves sensitivity while preserving specificity over single-phase CTA.


Author(s):  
Yury A. Morozov

The aim of the work. The effect of the curvature of the rounding of torus surfaces during the formation of a cylindrical product (glass) is investigated, taking into account the plastic thinning of the deformable material at the end edges of the matrix and pressing punch. Methods. The existing scheme for determining the power parameters of sheet drawing is analyzed, based on the assumption of the implementation of some abstract stress state in the material; mainly conditional tensile strength. At the same time, the possibility of forming the product without destruction determines the obvious overestimation of the stress level. A mathematical model of the volumetric stress state of the metal is being developed, which makes it possible to assess the deformation and stress state during the formation of a cold-drawn product, i. e. the folding of the sheet blank along the end radius of the rounding of the pressing punch and the steady-state process of drawing the blank into the deformation zone with successive bending/straightening of the material along the edge of the matrix are considered. The level of radial stresses during folding and stretching of sheet material is estimated, taking into account its strain hardening and thinning, which determine the forming force. The obtained results will make it possible to simulate the stress-strain state of the metal during the development of sheet drawing technology: to establish the amount of thinning, to estimate the level of radial stresses in the formation of rounding of torus surfaces along the end edges of the matrix and the pressing punch, as well as to determine the power parameters of the formation, which will prevent the destruction of the pulled part, guaranteeing obtaining high-quality products and more accurately choosing the deforming equipment.


2018 ◽  
Vol 20 (3) ◽  
pp. 362-372 ◽  
Author(s):  
Katharina Schregel ◽  
Ioannis Tsogkas ◽  
Carolin Peter ◽  
Antonia Zapf ◽  
Daniel Behme ◽  
...  

Author(s):  
Hafiz Muhammad Yasir Naeem ◽  
Aamer Iqbal Bhatti ◽  
Yasir Awais Butt ◽  
Qadeer Ahmed

Limited capacity and short life cycle of a battery are the major impediments in development of practical Electric Vehicles (EVs). Eco-driving is an optimization technique through which a velocity trajectory that consumes minimum energy is advised to the driver. However, presence of traffic signals to control large traffic network degrades the performance of eco-driving; as applying brakes to stop and then maximum re-acceleration to restart a trip consumes lot of energy. Eco-driving problem with multiple traffic signals and static model of battery has been proposed as Two Point Boundary Value Problem (TPBVP). TPBVP fails to solve multi-phase problem as a single phase due to discontinuity of the co-states at the junction, that is, start of a new phase. This paper investigates an optimal solution with both EV and battery dynamics in the presence of multiple traffic signals as Multi Point Boundary Value Problem (MPBVP) using multiple shooting technique. Traffic signals come at some intermediate points of a trip. MPBVP ensures continuity at the junction to solve the multi-phase problem as a single phase through inter dependencies between each phases. Goal of this work is not only to solve constrained eco-driving problem with traffic signals but also include charging and discharging limits on battery that indirectly improves battery’s life cycle. Results indicate that EV has crossed all the traffic signals during their green duration without applying brakes with also satisfying all the other constraints and continuity condition. Moreover, it can be seen that energy consumption using MPBVP is also marginally lesser as compared to TPBVP.


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