4,787 research outputs found
CW and pulsed electrically detected magnetic resonance spectroscopy at 263 GHz/12 T on operating amorphous silicon solar cells
Here we describe a new high frequency/high field continuous wave and pulsed
electrically detected magnetic resonance (CW EDMR and pEDMR) setup, operating
at 263 GHz and resonance fields between 0 and 12 T. Spin dependent transport in
illuminated hydrogenated amorphous silicon p-i-n solar cells at 5 K and 90 K
was studied by in operando 263 GHz CW and pEDMR alongside with complementary
X-band CW EDMR. Benefiting from the superior resolution at 263 GHz, we were
able to better resolve EDMR signals originating from spin dependent hopping and
recombination processes. 5 K EDMR spectra were found to be dominated by
conduction and valence band tale states involved in spin dependent hopping,
with additional contributions from triplet exciton states. 90 K EDMR spectra
could be assigned to spin pair recombination involving conduction band tail
states and dangling bonds as dominating spin dependent transport process, with
additional contributions from valence band tail and triplet exciton states.Comment: 8 pages, 4 figure
Basel II, External Ratings and Adverse Selection
This paper will describe and analyse the development of Basel II Capital Accord and will focus on the use of external ratings in the Standardized Approach in Basel II. Furthermore it will examine the problem of adverse selection which appears in Basel II as a result from the proposal for the use of external ratings in determining the risk weights in the standardized approach. The paper will also attempt to find possible solutions to the adverse selection problem by discussing two similar models, and derive implications from them.Basel II, external ratings, adverse selection, rating agencies, standardized approach
Charge-noise-free Lateral Quantum Dot Devices with Undoped Si/SiGe Wafer
We develop quantum dots in a single layered MOS structure using an undoped
Si/SiGe wafer. By applying a positive bias on the surface gates, electrons are
accumulated in the Si channel. Clear Coulomb diamond and double dot charge
stability diagrams are measured. The temporal fluctuation of the current is
traced, to which we apply the Fourier transform analysis. The power spectrum of
the noise signal is inversely proportional to the frequency, and is different
from the inversely quadratic behavior known for quantum dots made in doped
wafers. Our results indicate that the source of charge noise for the doped
wafers is related to the 2DEG dopant.Comment: Proceedings of the 12th Asia Pacific Physics Conferenc
Achieving Universal Salt Iodisation (USI) in Pakistan: Challenges, Experiences and the Way Forward
This article aims to describe the history, progress, success and challenges of the Universal Salt Iodisation (USI) programme in Pakistan, which was launched in 1994. Revitalised in 2005 with financial assistance and technical, operational, logistic and commodity support from the Micronutrient Initiative (MI), it is now being implemented in 102 districts of Pakistan. With an increase in household utilisation of iodised salt from 17 per cent in 2001 to 69 per cent in 2011, severe iodine deficiency among women and school?aged children has decreased to 3 per cent and 2 per cent respectively. Strong government ownership and commitment, coupled with effective monitoring and supervision, have been the driving force of the USI Pakistan programme. These, combined with quality control measures, stringent regulatory and enforcement mechanisms, availability of fortificants in the open market and demand generation are the necessary requirements for programme sustainability
Rethinking interpretation: Input-agnostic saliency mapping of deep visual classifiers
Saliency methods provide post-hoc model interpretation by attributing input
features to the model outputs. Current methods mainly achieve this using a
single input sample, thereby failing to answer input-independent inquiries
about the model. We also show that input-specific saliency mapping is
intrinsically susceptible to misleading feature attribution. Current attempts
to use 'general' input features for model interpretation assume access to a
dataset containing those features, which biases the interpretation. Addressing
the gap, we introduce a new perspective of input-agnostic saliency mapping that
computationally estimates the high-level features attributed by the model to
its outputs. These features are geometrically correlated, and are computed by
accumulating model's gradient information with respect to an unrestricted data
distribution. To compute these features, we nudge independent data points over
the model loss surface towards the local minima associated by a
human-understandable concept, e.g., class label for classifiers. With a
systematic projection, scaling and refinement process, this information is
transformed into an interpretable visualization without compromising its
model-fidelity. The visualization serves as a stand-alone qualitative
interpretation. With an extensive evaluation, we not only demonstrate
successful visualizations for a variety of concepts for large-scale models, but
also showcase an interesting utility of this new form of saliency mapping by
identifying backdoor signatures in compromised classifiers.Comment: Accepted for publication in AAAI 202
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