1,236 research outputs found
AAS227 - Synthesizing Understanding from Data with yt
No full textThis is a talk I gave at the AAS227 about yt. yt is available at yt-project.org.<div><br></div><div>While I am listed as the author of this talk, the yt community is composed of more than a hundred code contributors and mailing list participants, and we are grateful to their involvement and support.</div><div><br></div><div>Additionally, the yt project is built on other members of the scientific software ecosystem such as Jupyter, NumPy, Cython, h5py and hdf5, Matplotlib, and Sympy.</div
Evidence on the formation of a heavily Ge-doped layer in Pd/Ge-based ohmic contact to pseudomorphic high electron mobility transistor
No full textMicrostructural evidence on the formation of a heavily Ge-doped layer below Pd/Ge-based ohmic contact to AlGaAs/InGaAs pseudomorphic high electron mobility transistor was obtained. The contact resistivity is decreased by two orders of magnitude as InGaAs channel is intermixed. This originates from the formation of Au2Al and Au7Ga2 compounds below the contacts during annealing, via production of group III vacancies. The vacancies play a role in producing free electrons by the incorporation of Ge atoms, resulting in intermixing of InGaAs as well as reduction of contact resistivity. (C) 1998 American Institute of Physics. [S0003-6951(98)01748-3].open111sciescopu
Characterization on Structural properties of Ge-Bi-Te ternary eutectic phase for PRAM application
No full textElectronic structure of Ge(111)c(2x8) : STM, angle-resolved photoemission, and theory
No full textThe surface electronic structure of Ge(111)c(2x8) was studied by experimental techniques [low-energy electron diffraction, scanning tunneling microscopy (STM), and angle-resolved photoelectron spectroscopy (ARPES)] and theoretical band-structure calculations. Bias-dependent STM images exhibit two different types of adatoms (A(T),A(R)) and rest atoms (R-T,R-R) confirming the presence of asymmetries within the c(2x8) cell. The ARPES study resulted in a more detailed picture of the surface electronic structure of the Ge(111)c(2x8) surface compared to earlier studies. The energy dispersion curves showed the presence of seven surface bands labeled A1, A2, A2(), A3, A4, A4(), and A5. The experimental surface bands were compared to the calculated band structure of the full c(2x8) unit cell. The most important results are (i) we have identified a split surface-state band in the photoemission data that matches a split between R-T and R-R derived rest atom bands in the calculated surface band structure. This allows us to identify the upper A2 band with the R-R and the lower A2() band with the R-T rest atoms. (ii) The uppermost highly dispersive band (A1) originates from states below the adatom and rest atom layers and should not be confused with rest atom bands A2 and A2(). (iii) The bias-dependent changes in the adatom/rest atom contrast in the experimental STM images were closely reproduced by simulated STM images generated from the calculated electronic structure. (iv) A split was observed in the back-bond derived surface band at higher emission angles (A4 and A4()).Original Publication:Ivy Razado, Jiangping He, Hanmin Zhang, Göran Hansson and Roger Uhrberg, Electronic structure of Ge(111)c(2x8): STM, angle-resolved photoemission, and theory, 2009, PHYSICAL REVIEW B, (79), 20, 205410.http://dx.doi.org/10.1103/PhysRevB.79.205410Copyright: American Physical Societyhttp://www.aps.org
Contact resistance degradation of Pd/Ge ohmic contact on pseudomorphic high electron mobility transistor
No full textThe contact resistance degradation mechanism of the Pd/Ge ohmic contact on a pseudomorphic high electron mobility transistor was interpreted. The contact resistance continuously degrades at temperatures higher than 300 degrees C although no microstructural changes were observed. Meanwhile, elemental Ga atoms were preferentially outdiffused to the PdGe layer and Ge atoms were indiffused to the GaAs during annealing. The indiffused Ge converts the interfacial GaAs layer into n-GaAs, in which Ga vacancies are produced to maintain the charge neutrality condition. The Ga vacancy concentration further increases with annealing temperature, which plays a role in degrading the contact resistance as a result of the recombination of electrons with the Ga vacancies. (C) 1998 American Vacuum Society.open11sciescopu
A maximal inequality for stochastic integrals
No full textAssume that X is a càdlàg, real-valued martingale starting from zero, H is a predictable process with values in [−1; 1] and Y =∫HdX. This article contains the proofs of the following inequalities: i If X has continuous paths, then Psupt≥0 Yt≥ 1≤ 2Esupt≥0Xt, where the constant 2 is the best possible.ii If X is arbitrary, thenPsupt≥0 Yt≥ 1≤ cEsupt≥0Xt, where c = 3.0446... is the unique positive number satisfying the equation 3c4 − 8c3 − 32 = 0. This constant is the best possible.Assume that X is a càdlàg, real-valued martingale starting from zero, H is a predictable process with values in [−1; 1] and Y =∫HdX. This article contains the proofs of the following inequalities: i If X has continuous paths, then Psupt≥0 Yt≥ 1≤ 2Esupt≥0Xt, where the constant 2 is the best possible.ii If X is arbitrary, thenPsupt≥0 Yt≥ 1≤ cEsupt≥0Xt, where c = 3.0446... is the unique positive number satisfying the equation 3c4 − 8c3 − 32 = 0. This constant is the best possible
Correction to: Chemoradiation in elderly patients with glioblastoma from the multiinstitutional GBMmolRPA cohort: is shortcourse radiotherapy enough or is it a matter of selection?
No full textThe name of author Do Hoon Lim was incorrect in the initial online publication. The original article has been corrected
Control optimisatlion of CO(2) cycles for medium temperature retail food refrigeration systems
No full textThis is the post-print version of the final paper published in International Journal of Refrigeration. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2009 Elsevier B.V.This paper describes a detailed procedure into the investigation of optimised control strategies for CO2 cycles in medium temperature retail food refrigeration systems. To achieve this objective, an integrated model was developed composing of a detailed condenser/gas cooler model, a simplified compressor model, an isenthalpic expansion process and constant evaporating temperature and superheating. The CO2 system can operate subcritically or transcritically depending on the ambient temperature. For a transcritical operation, a prediction can be made for optimised refrigerant discharge pressures from thermodynamic cycle calculations. When the system operates in the subcritical cycle, a floating discharge pressure control strategy is employed and the effect of different transitional ambient temperatures separating subcritical and transcritical cycles on system performance is investigated. The control strategy assumes variable compressor speed and adjustable air flow for the gas cooler/condenser to be modulated to achieve the constant cooling load requirement at different ambient conditions.DEFR
Effect of donepezil on transcranial magnetic stimulation parameters in Alzheimer's disease
No full textIntroduction: There is a need for a reliable, noninvasive biomarker for Alzheimer's disease (AD). We assessed whether short-latency afferent inhibition (SAI), a transcranial magnetic stimulation paradigm that assesses cholinergic circuits of the brain, could become such a biomarker.
Methods: Nineteen patients with AD underwent four SAI testing sessions. The timing of their usual donepezil dose was altered to create different cholinergic states for each session. This was compared to the SAI results from 20 healthy subjects.
Results: SAI was not able to distinguish the different cholinergic states assessed in our study. There appeared to be a diurnal variation in cholinergic function in the control group, which was not present in the AD cohort.
Discussion: SAI does not appear to have a role in diagnosis and assessment of AD patients. The loss of diurnal variation, however, warrants further investigation as it may provide further biochemical insights about AD
Performance evaluation and optimal design of supermarket refrigeration systems with supermarket model "SuperSim", Part I: Model description and validation
No full textThis is the post-print version of the final paper published in International Journal of Refrigeration. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.Conventional supermarket refrigeration systems are responsible for considerable CO2 emissions due to high energy consumption and large quantities of refrigerant leakage. In the effort to conserve energy and reduce environmental impacts, an efficient design tool for the analysis, evaluation and comparison of the performance of alternative system designs and controls is required. This paper provides a description of the modelling procedure employed in the supermarket simulation model ‘SuperSim’ for the simulation of the performance of centralised vapour compression refrigeration systems and their interaction with the building envelope and HVAC systems. The model which has been validated against data from a supermarket has been used for the comparison of R404A and CO2 refrigeration systems and the optimisation of the performance of transcritical CO2 systems. These results are presented in Part II of the paper.DEFR
- …
