Experimental and physical approaches on a novel semiconducting-ionic membrane fuel cell

Semiconducting-ionic membranes (SIMs) have exhibited significant superiority to replace the conventional ionic electrolytes in solid oxide fuel cells (SOFCs). One interesting phenomenon is that the SIMs can successfully avoid the underlying short-circuiting issue and power losses while bringing significantly enhanced power output. It is crucial to understand the physics in such devices as they show distinct electrochemical processes with conventional fuel cells. We first presented experimental studies of a SIM fuel cell based on a composite of semiconductor LiCo_0.8Fe_0.2O₂ (LCF) and ionic conductor Sm-doped CeO₂ (SDC), which achieved a remarkable power density of 1150 mW cm^?2 at 550 °C along with a high open circuit voltage (OCV) of 1.04 V. Then, for the first time we used a physical model via combining a semiconductor-ionic contact junction with a rectifying layer which blocks the electron leakage to describe such unique SIM device and excellent performance. Current and power are the most important characteristics for the device, by introducing the rectifying layer we described the SIM physical nature and new device process. This work presented a new view on advanced SIM SOFC science and technology from physics.     

Communication—Processor Tradeoffs in a Limited Resources PRAM

We consider a simple restriction of the PRAM model (called PPRAM), where the input is arbitrarily partitioned between a fixed set of p processors and the shared memory is restricted to m cells. This model allows for investigation of the tradeoffs/ bottlenecks with respect to the communication bandwidth (modeled by the shared memory size m ) and the number of processors p . The model is quite simple and allows the design of optimal algorithms without losing the effect of communication bottlenecks. We have focused on the PPRAM complexity of problems that have $\tilde{O}$ (n) sequential solutions (where n is the input size), and where m ≤ p ≤ n . We show essentially tight time bounds (up to logarithmic factors) for several problems in this model such as summing, Boolean threshold, routing, integer sorting, list reversal and k -selection. We get typically two sorts of complexity behaviors for these problems: One type is $\tilde{O}$ (n/p + p/m) , which means that the time scales with the number of processors and with memory size (in appropriate ranges) but not with both. The other is $\tilde{O}$ (n/m) , which means that the running time does not scale with p and reflects a communication bottleneck (as long as m < p ). We are not aware of any problem whose complexity scales with both p and m (e.g. $O(n/\sqrt{m \cdot p})$ ). This might explain why in actual implementations one often fails to get p -scalability for p close to n .     

Morphology of the inferior frontal gyrus in developmentally language-disordered adults

The inferior frontal gyrus has traditionally been considered an important cortical region for language and may be important for understanding developmental language disorders. The morphology of the inferior frontal gyrus, as it appeared on T1-weighted sagittal magnetic resonance imaging (MRI) scans, was evaluated using a classification system that distinguished between seven basic morphological variants of the gyral and sulcal patterns in this region. This classification scheme was applied to the MRI scans of 41 neurologically normal adult subjects. To examine the relation between sulcal morphology and subject status, these subjects were sorted first by family history for developmental language disorders and then resorted by expression of behavioral signs consistent with a diagnosis of this disorder as determined by standardized testing. Morphological types that included an extra sulcus in the inferior frontal gyrus were statistically associated with the behaviorally based classification of subjects, but not with a positive family history for developmental language disorders. Because gyral patterns are prenatally determined, this finding is consistent with the theory that altered prenatal development contributes to the expression of a developmental language disorder.     

One electron reduction of metmyoglobin and methemoglobin and the reaction of the reduced molecule with oxygen

We have used the pulse radiolysis technique to reduce with solvated electrons (see article) a single Fe(III) site in methemoglobin and metmyoglobin. The reduction process was followed spectrophotometrically and the reactions rate constants were measured: (see article) =6.5 +/- 1-10(10) M-1-S-1. (see article)=2.5 +/- 0.3-10(10) M-1-S-1. Approx. 60% of the (see article) have reacted with the hemin group, and the rest of the (see article) have probably reacted with the globin moiety. We followed the reaction of the reduced proteins to yield the oxyderivatives and measured the rate constants of the oxygenation process k reduced methemoglobin + O2 = 2.6 +/- 0.6-10(7) M-1-S-1 and k myoglobin + O2 = 1.8 +/- 0.2-10(7) M-1-S-1, all the rate constants were measured at pH = 6.8, I = 0.004, T = 22 +/- 2 degrees C. The high rate constant for reduced methemoglobin indicates that one-site-reduced methemoglobin is probably in the R state, as predicted for methemoglobin from X-ray analysis. The spectra of the reduced and oxygenated species were measured under similar conditions at gamma = 450-650 nm. We were able to follow slight changes in the micro-second time scale, these changes were attributed to conformational changes. We were not able to detect any reaction between the radical (see article) and the hemin group (which would result in a complex such as heme O-2). This may be due to kinetic reasons.     

Inferring the capacity of the vector Poisson channel with a Bernoulli model

The capacity defines the ultimate fidelity limits of information transmission by any system. We derive the capacity of parallel Poisson process channels to judge the relative effectiveness of neural population structures. Because the Poisson process is equivalent to a Bernoulli process having small event probabilities, we infer the capacity of multi-channel Poisson models from their Bernoulli surrogates. For neural populations wherein each neuron has individual innervation, inter-neuron dependencies increase capacity, the opposite behavior of populations that share a single input. We use Shannon's rate-distortion theory to show that for Gaussian stimuli, the mean-squared error of the decoded stimulus decreases exponentially in both the population size and the maximal discharge rate. Detailed analysis shows that population coding is essential for accurate stimulus reconstruction. By modeling multi-neuron recordings as a sum of a neural population, we show that the resulting capacity is much less than the population's, reducing it to a level that can be less than provided with two separated neural responses. This result suggests that attempting neural control without spike sorting greatly reduces the achievable fidelity. In contrast, single-electrode neural stimulation does not incur any capacity deficit in comparison to stimulating individual neurons.     

Modeling alternative zoning strategies in forest management

To satisfy public demands for environmental values, forest companies are facing the prospect of a reduction in wood supply and increases in costs. Some Canadian provincial governments have proposed intensifying silviculture in special zones dedicated to timber production as the means for pushing out the forest possibility frontiers. In this paper, we compare the traditional two‐zone land allocation framework which includes ecological reserves and integrated forest management zones with the triad — a three‐zone scheme which adds a zone dedicated to intensive timber production. We compare the solutions of the mixed‐integer linear programs formulated under both land‐allocation frameworks. We explore through sensitivity analysis the conditions under which the triad regime can offset the impact on timber production from increased environmental demands. We show that under the realistic conditions characteristic to Coastal British Columbia, higher environmental demands may be satisfied under the triad regime without increasing the financial burdens on the industry or reducing its wood supply. This occurs, however, only if regulatory constraints in timber production zone are flexible.     

On the Effective Deployment of Functional Formal Verification

We examine IBM's exploitation of formal verification using RuleBase—a formal verification tool developed by the IBM Haifa Research Laboratory. The goal of the paper is methodological. We identify an integrated methodology for the deployment of formal verification which involves three complementary modes: architectural verification, block-level verification, and design exploration.     

A Typology for Multi-Technology, Multi-Service Broadband Network Synthesis

Current technological possibilities for implementing multi-service networks include both single technology ATM or IP networks and multi-technology networks such as SONET-based or flat networks. However, regardless of the technology employed, the synthesis problem – to optimally route traffic and divide the network's transmission resources between its virtual links – remains of prime importance.In this paper, we review, compare, and classify the extensive recent literature concerning multi-service network synthesis methods. In order to do this, we propose a typology based on switching and control strategies and a general notation that reflects the layered nature of the network. Technology independent mathematical models describe the various, essentially different, approaches presently found in the literature.