54 research outputs found
Visualizing CPU Microarchitecture
Deep understanding of microprocessor architecture, its internal structure and mechanics of its work is essential for engineers in the fields like computer science, integrated circuit design or embedded systems (including microcontrollers). Usually the CPU architecture is presented at the level of ISA, functional decomposition of the chip and data flows. In this paper we propose more tangible, interactive and effective approach to present the CPU microarchitecture. Based on the recent advancements in simulation of MOS6502, one of the most successful microprocessor of all times, that started the personal computing revolution, we present the CPU visualisation framework. The framework supports showing CPU internals at various levels (from single transistor, through logic gates, ending with registers, operation decoders and ALU). It allows for execution of real code and detailed analysis of fetch–decode–execute cycle, measurement of cycles per operation or measurement of the CPU activity factor. The analysis means provided by this framework will also enable us to propose the transistor level simulation speed improvements to the model in the future
Java Based Transistor Level CPU Simulation Speedup Techniques
Transistor level simulation of the CPU, while very accurate, brings also the performance challenge. MOS6502 CPU simulation algorithm is analysed with several optimisation techniques proposed. Application of these techniques improved the transistor level simulation speed by a factor of 3–4, bringing it to the levels on par with fastest RTL-level simulations so far
Magnetization dynamics down to zero field in dilute (Cd,Mn)Te quantum wells
The evolution of the magnetization in (Cd,Mn)Te quantum wells after a short
pulse of magnetic field was determined from the giant Zeeman shift of
spectroscopic lines. The dynamics in absence of magnetic field was found to be
up to three orders of magnitude faster than that at 1 T. Hyperfine interaction
and strain are mainly responsible for the fast decay. The influence of a hole
gas is clearly visible: at zero field anisotropic holes stabilize the system of
Mn ions, while in a magnetic field of 1 T they are known to speed up the decay
by opening an additional relaxation channel
Stark Spectroscopy and Radiative Lifetimes in Single Self-Assembled CdTe Quantum Dots
We present studies on Coulomb interactions in single self-assembled CdTe
quantum dots. We use a field effect structure to tune the charge state of the
dot and investigate the impact of the charge state on carrier wave functions.
The analysis of the quantum confined Stark shifts of four excitonic complexes
allows us to conclude that the hole wave function is softer than electron wave
function, i. e. it is subject to stronger modifications upon changing of the
dot charge state. These conclusions are corroborated by time-resolved
photoluminescence studies of recombination lifetimes of different excitonic
complexes. We find that the lifetimes are notably shorter than expected for
strong confinement and result from a relatively shallow potential in the
valence band. This weak confinement facilitates strong hole wave function
redistributions. We analyze spectroscopic shifts of the observed excitonic
complexes and find the same sequence of transitions for all studied dots. We
conclude that the universality of spectroscopic shifts is due to the role of
Coulomb correlations stemming from strong configuration mixing in the valence
band.Comment: sent to Physical Review
The retrospective study of 93 patients with transmigration of mandibular canine and a comparative analysis with a control group
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