Theory of the Exciton-Phonon Coupling

The effect of electron-phonon interactions on optical absorption spectra requires a special treatment in materials with strong electron-hole interactions. We conceptualize these effects as exciton-phonon coupling. Through phonon absorption and emission, the optically accessible excitons are scattered into dark finite-momentum exciton states. We derive a practical expression for the exciton-phonon self-energy that relates to the temperature dependence of the optical transitions and their broadening. This expression differs qualitatively from previous approximated expressions found in literature

An Analysis of Theme and Rheme Used in the Five-star Hotels' Web Sites in Surabaya

The study done by the writer observes the themes and rhemes used in the five-star hotels' web sites in Surabaya. It includes the types of themes and the notions of subject which are under the Systemic Functional Grammar (SFG) proposed by Halliday and Matthiessen (2004). In addition, the data of the study are in the form of text and taken from seven Surabaya five-star hotels' web sites. The writer also used a descriptive qualitative approach in analyzing the 155 data. From the analysis, it is found the two kinds of structure of theme and rheme used by the hotels in their web sites. The hotels also used three types of theme which are simple theme, clause as a theme, and thematic equative. In terms of the subjects (psychological subject, grammatical subject, and logical subject), the hotels are able to fulfill either one, two, or three notions of subject

Quasi-Langmuir-Blodgett Thin Film Deposition of Carbon Nanotubes

The handling and manipulation of carbon nanotubes continues to be a challenge to those interested in the application potential of these promising materials. To this end, we have developed a method to deposit pure nanotube films over large flat areas on substrates of arbitrary composition. The method bears some resemblance to the Langmuir-Blodgett deposition method used to lay down thin organic layers. We show that this redeposition technique causes no major changes in the films' microstructure and that they retain the electronic properties of as-deposited film laid down on an alumina membrane.Comment: 3 pages, 3 figures, submitted Journal of Applied Physic

Evaluating Rapid Application Development with Python for Heterogeneous Processor-based FPGAs

As modern FPGAs evolve to include more het- erogeneous processing elements, such as ARM cores, it makes sense to consider these devices as processors first and FPGA accelerators second. As such, the conventional FPGA develop- ment environment must also adapt to support more software- like programming functionality. While high-level synthesis tools can help reduce FPGA development time, there still remains a large expertise gap in order to realize highly performing implementations. At a system-level the skill set necessary to integrate multiple custom IP hardware cores, interconnects, memory interfaces, and now heterogeneous processing elements is complex. Rather than drive FPGA development from the hardware up, we consider the impact of leveraging Python to ac- celerate application development. Python offers highly optimized libraries from an incredibly large developer community, yet is limited to the performance of the hardware system. In this work we evaluate the impact of using PYNQ, a Python development environment for application development on the Xilinx Zynq devices, the performance implications, and bottlenecks associated with it. We compare our results against existing C-based and hand-coded implementations to better understand if Python can be the glue that binds together software and hardware developers.Comment: To appear in 2017 IEEE 25th Annual International Symposium on Field-Programmable Custom Computing Machines (FCCM'17