Materials and Their Characteristics: Overview

Czichos, Horst

doi:10.1007/978-3-540-30300-8_3

Cited by 46 publications

(77 citation statements)

References 3 publications

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“…General rules of the advanced modeling of VCSEL operation were also formulated by Osiński and Nakwaski [12]. Electrical conductivities of semiconductor layers depend on their doping and free carrier concentration [13]. Their values are determined using experimental data reported in Refs.…”

Section: Theoretical Modelmentioning

confidence: 99%

Optimization of GaInNAs quantum-well vertical-cavity surface-emitting laser emitting at 2.33 μm

et al. 2013

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In the present paper, a comprehensive computer simulation is used to determine optimal structure of the InPbased GaInNAs quantum-well (QW) active region and to investigate a possibility of reaching room-temperature (RT) continuous-wave (CW) single-fundamental-mode 2.33-µm operation of vertical-cavity surface-emitting laser (VCSEL) with such an active region. From among various considered InP-based active regions, the one with the Ga 0.15 In 0.85 N 0.015 As 0.985 /Al 0.138 Ga 0.332 In 0.530 As QW, i.e. with barriers lattice matched to InP, seems to be optimal for the 2.33-µm VCSEL performance. Its QW material is chosen for the required long-wavelength emission whereas its barrier is expected to ensure promising laser performance at room and higher temperatures. The latter is mostly connected with the QW conduction band offset equal in the above active region to as much as 413 meV, which is much larger than those of its possible lattice matched to InP competitors, e.g. 276 meV for the Ga 0.47 In 0.53 As barrier and 346 meV for the Ga 0.327 In 0.673 As 0.71 P 0.29 one. Our simulation reveals that from among various considered structures, a VC-SEL with a 4-µm-diameter tunnel junction and two 6-nm Ga 0.15 In 0.85 N 0.015 As 0.985 /Al 0.138 Ga 0.332 In 0.530 As QWs exhibits the lowest calculated threshold current of 0.88 mA. Its promising RT CW performance suggests that it may represent a very interesting alternative to GaSb-based VCSELs.

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Section: Theoretical Modelmentioning

confidence: 99%

Optimization of GaInNAs quantum-well vertical-cavity surface-emitting laser emitting at 2.33 μm

et al. 2013

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“…In order to improve or manipulate the friction and wear performance of a tribological system, different strategies exist. Common approaches are the use of improved materials with regard to the desired properties, the employment of lubrication, or the application of coatings [1].…”

Section: Introductionmentioning

confidence: 99%

Friction and Wear Measurements with an Adapted Ball-On-Pyramid Test Setup

Krasmik

Schlattmann

2016

Tribology Online

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In tribological testing with simplified test geometries, the contact configurations usually consist of two bodies representing one material pairing. This contribution introduces an adapted ball-on-pyramid test configuration which allows the experimental investigation of combined contact configurations consisting of more than one material pairing. In the proposed test setup, a ball is loaded against four flat test samples positioned in a pyramid-like sample holder with an opening angle of 90°. The test samples are arranged on the circumference in a regular manner. The ball rotates uniformly around its vertical axis and slides over the samples. The coefficient of friction, the running-in wear, the linear wear rate, the wear scar diameter, and the weight loss of four different sample materials and their combinations are compared and discussed. The obtained results for combined contact configurations with more than one material pairing show that a manipulation of the friction and wear characteristics is possible.

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“…The main advantages of the Vickers hardness test are that accurate readings can be taken, and just one type of indenter is used for all types of metals and surfaces treatments [11]. The "true value" of hardness is achieved by the "skill operator", using an "ideal standards hardness calibration machine" with the "ideal indenter" and applying the standards without substantial error [12].…”

Section: Introductionmentioning

confidence: 99%

“…The area of the indentation surface is calculated. Vickers hardness value is obtained by dividing the applied load by the area of indentation using the following equation [11].…”

Section: Introductionmentioning

confidence: 99%

The influence of geometrical tolerances of Vickers indenter on the accuracy of measured hardness

El‐Sherbiny

Hegazy

Ibrahim

et al. 2012

Int. J. Metrol. Qual. Eng.

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Abstract. This paper reports work carried out to determine the influence of the Pyramidal indenter geometrical errors and tolerances on the accuracy of Vickers hardness measurements. The angle between the opposite faces and line of conjunction of nine indenters were measured by the optical comparator. The influence of the indenter geometry on the hardness accuracy is investigated. Three calibrated reference hardness test blocks were used to check the Vickers hardness test using the nine selected indenters. The results show that the geometrical error of the indenters (specially the angles) considerably affects the accuracy of the hardness measurement. Finite element analysis of the indentation process into metallic test pieces was conducted. Comparison of the experimental results with the numerical findings was discussed. Errors in the experimental values are correlated with measured tolerances in the angles between faces.

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Materials and Their Characteristics: Overview

Cited by 46 publications

References 3 publications

Optimization of GaInNAs quantum-well vertical-cavity surface-emitting laser emitting at 2.33 μm

Optimization of GaInNAs quantum-well vertical-cavity surface-emitting laser emitting at 2.33 μm

Friction and Wear Measurements with an Adapted Ball-On-Pyramid Test Setup

The influence of geometrical tolerances of Vickers indenter on the accuracy of measured hardness

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