High efficiency, low cost thin GaAs solar cells

The feasibility of fabricating space-resistant, high efficiency, light-weight, low-cost GaAs shallow-homojunction solar cells for space application is demonstrated. This program addressed the optimal preparation of ultrathin GaAs single-crystal layers by AsCl3-GaAs-H2 and OMCVD process. Considerable progress has been made in both areas. Detailed studies on the AsCl3 process showed high-quality GaAs thin layers can be routinely grown. Later overgrowth of GaAs by OMCVD has been also observed and thin FaAs films were obtained from this process

Shallow-homojunction GaAs solar cells

Single-crystal GaAs shallow-homojunction solar cells on GaAs or Ge substrates, without Ga sub 1-x Al sub x As window layers, that have conversion efficiencies exceeding 20% at AM1 (17% at AMO). Using a simple theoretical model, good fits were obtained between computer calculations and experimental data for external quantum efficiency and conversion efficiency of cells with different values of n+ layer thickness. The calculations not only yield values for material properties of the GaAs layers composing the cells but will also permit the optimization of cell designs for space and terrestrial applications. Preliminary measurements indicate that the shallow-homojunction cells are resistant to electron irradiation. In the best test so far, bombardment with 1 x 10 to the 16th power/sq cm fluence of 1 MeV electrons reduced the short-circuit current by only about 6%

Internationalisation of Spanish fashion brand Zara

Zara is one of the world’s most successful fashion retailers operating in 59 countries. However, there is little research about the firm in English as the majority of publications have been written in Spanish. This paper seeks to address this gap in the literature by examining the internationalisation process of Zara. This study adopts an in-depth case approach based on extensive secondary research. Literature published in both English and Spanish has been reviewed, including company documents such as annual reports. The paper starts with a brief overview of the global textile and clothing industry, followed by the case study of Zara. The main part of the case examines the key aspects in the internationalisation of Zara namely: motives for internationalisation, market selection, entry strategies, and international marketing strategies. In the final section, comparisons are made between Zara and two of its main competitors, H&M and Gap

THE LUXURY AXIOM, THE WEALTH PARADOX, AND CHILD LABOR

Basu and Van (1998) present a fundamental framework of child labor with two important axioms: the luxury axiom and the substitution axiom. A number of empirical studies, however, reveal a ¡°wealth paradox¡±. The current paper has two aims. First, it develops a model that provides an explanation for ¡°the wealth paradox¡± in light of the luxury axiom and the substitution axiom. Second, it helps understand the relationship between the luxury axiom and the substitution axiom.Child Labor, Luxury Axiom, Wealth Paradox, Substitution Axiom

Scaling from Jupiter to pulsars and the acceleration of cosmic ray particles by pulsars, 3

An expression for the rate of energy generation by a pulsar an estimate of contribution from all the pulsars in our galaxy to the observed cosmic ray intensity was presented. The theory was then developed to an expanded version, and observational facts supporting the theory were cited