Perfect absorption in ultra-thin uniform and nanostructured media

© OSA 2015. We show that perfect absorption can be achieved in ultra-thin gratings composed of weakly absorbing dielectric materials combined with a mirror. The structures can be fabricated using standard processing techniques

Mode-based analysis of silicon nanohole arrays for photovoltaic applications

We investigate the optical properties of silicon nanohole arrays for application in photovoltaic cells in terms of the modes within the structure. We highlight three types of modes: fundamental modes, important at long wavelengths; guided resonance modes, which enhance absorption for wavelengths where the intrinsic absorption of silicon is low; and channeling modes, which suppress front-surface reflection. We use this understanding to explain why the parameters of optimized nanohole arrays occur in specific ranges even as the thickness is varied. © 2014 Optical Society of America

Supervision of Chinese social work students during field practice: Harmonising a student-focused, egalitarian approach with traditional teaching and learning

This article explores the extent to which approaches to supervision developed outside of China fit with Chinese cultural approaches to learning and teaching. Qualitative data were collected from students and supervisors from three different regions in China. The findings suggest that a student-focused, egalitarian approach is fundamental to promote students’ learning at the current developmental stage of the social work profession in China. This approach is in conflict to some degree with the deeply rooted traditional teacher-centred, authoritative teaching and learning style. This study illustrates how a student-focused, equalitarian approach could be applied to alleviate such a tension

Total absorption of visible light in ultrathin weakly absorbing semiconductor gratings

© 2016 Optical Society of America. The perfect absorption of light in subwavelength thickness layers generally relies on exotic materials, metamaterials or thick metallic gratings. Here we demonstrate that total light absorption can be achieved in ultra-thin gratings composed of conventional materials, including relatively weakly-absorbing semiconductors, which are compatible with optoelectronic applications such as photodetectors and optical modulators. We fabricate a 41 nm thick antimony sulphide grating structure that has a measured absorptance of A = 99.3% at a visible wavelength of 591 nm, in excellent agreement with theory. We infer that the absorption within the grating is A = 98.7%, with only A = 0.6% within the silver mirror. A planar reference sample absorbs A = 7.7% at this wavelength

Bulgarian sport policy 1945-1989: A strategic relation perspective

The 2008 Beijing Olympic Games have stimulated discussions about the success of different sport systems and the Chinese model in particular. Revisiting explanations of sport in the former communist countries of Eastern Europe during the Cold War seems timely, as the current Chinese model of sport was largely designed after the Soviet example established in this period. This paper examines Bulgarian sport policy between 1945 and 1989. It employs a Strategic Relation approach (Jessop, 1990) to analyse sport policy making as a strategic relation closely linked to the dominant state project of building a new stateness. It goes beyond ideological interpretations and argues that the state represents a strategic terrain where these relations have to be established in struggles, the outcomes of which are always uncertain. Furthermore, past and present struggles and their outcomes create various socio-political environments that presuppose the forms of state selectivity and intervention in sport. The process of constructing sport policy was influenced by two main categories of strategic relations: intra-state, including political, organisational and personal relations between the Party, state apparatus and various sport and non-sport organisations and their managers, and transnational, concerning ideological, political, economic and organisational relations with both communist and western countries and international sport organisations

企業の防災対策とBCP（事業継続計画）の課題 : なぜ多くの企業の災害への備えが，いまだおろそかなのか

1.はじめに 2.防災対策の課題 3.防災啓発活動のあり方 4.個人防災と企業防災 5.BCPの意義と役割 6.BCM ～期待される防災マネジメント 7.おわり