Biophysical Model of Larval Yellow Perch Advection and Settlement in Lake Michigan

Potential for large-scale physical transport processes to affect recruitment of Lake Michigan yellow perch (Perca flavescens) was studied by examining the variation in larval distribution, growth rate, and settlement during June–August 1998–2003 using a 3D particle transport model linked with an individual-based bioenergetics growth model. In all years, virtual larvae were released nearshore in southwestern Lake Michigan, a known and important spawning region for yellow perch. For any given year, the same circulation pattern and water temperature either promoted or reduced yellow perch settlement depending on the consumption rates and settlement size chosen in the growth model. Increased consumption increased the number of settled larvae and expanded the total area where larvae settled, whereas increased settlement size reduced the number of settled larvae and reduced the overall settlement area. Interannual variability in circulation patterns and water temperature also resulted in contrasting larval settlement rates, settlement locations, and size of settlement areas between years. Model predictions were most consistent with field observations of age-0 yellow perch from Illinois and Michigan waters when settlement was assumed to occur at 50 mm. Moreover, our model suggests that larvae originating from southwestern Lake Michigan can recruit anywhere within the southern basin and even in the northern basin. Future model improvement will require information on the relative contribution of various sectors to the larval pool, their distribution with reference to the hydrodynamic landscape, the feeding and growth of yellow perch during their pelagic phase, and the size at transition to demersal stage.     

Carbon nanotube field emitters for planar emission vacuum micro-and nanoelectronics

The design and manufacturing technology of carbon nanotube field emitters for novel devices of planar emission vacuum micro-and nanoelectronics are described. Prototypes of diode structures with such emitters are obtained in which the threshold field strength amounts to ～2 V/μm and the direct to reverse current ratio exceeds 10⁵. The obtained small scatter of characteristics points to the possibility of creating integrated circuits possessing high operation speed and a working temperature range expanded from ?60 to +30°C.     

Dispirooxindole-β-Lactams: Synthesis via Staudinger Ketene-Imine Cycloaddition and Biological Evaluation

In this work, we present the first synthesis of dispirooxindole-β-lactams employing optimized methodology of one-pot Staudinger ketene-imine cycloaddition with N-aryl-2-oxo-pyrrolidine-3-carboxylic acids as the ketene source. Spiroconjugation of indoline-2-one with β-lactams ring is considered to be able to provide stabilization and wide scope of functionalization to resulting scaffolds. The dispipooxindoles obtained demonstrated medium cytotoxicity in the MTT test on A549, MCF7, HEK293, and VA13 cell lines, and one of the compounds demonstrated antibacterial activity against E. coli strain LPTD.     

Effect of Copper on the Carrier Lifetime in Black Silicon

Black silicon is produced by laser annealing of a-Si:H films. During annealing, silicon microstructures are formed on the surface. We use time-resolved terahertz spectroscopy to study the photoconductivity dynamics in black silicon. We find that when a copper film is deposited on top of the a-Si:H layer prior to laser annealing, the carrier lifetime of black silicon is significantly reduced.     

Chaos at Interface Brings Order into Oxide/Silicon Structure

Integration of oxides with silicon fuses advanced functional properties with a mature technological platform. In particular, direct EuO/Si contact holds high promise for spintronics but requires single-crystalline epitaxial films with atomically sharp interfaces. The standard approach employing regular 2D superstructures of metal atoms on the Si surface fails to meet the challenge. Here, an alternative route is designed and shown to solve the problem. This route avoids regular templates; the chaotic 2D distribution of metal atoms on the Si surface prevents stabilization of unwanted crystal orientations. Thus, the disordered submonolayer phase at the interface promotes order in oxide/Si coupling, as witnessed by a combination of diffraction techniques and high-resolution electron microscopy. The results not only mark tangible progress in manufacturing EuO/Si contacts but also provide a general framework for monolithic integration of functional oxides with semiconductor substrates.     

System fault-tolerance analysis of COTS-based satellite on-board computers

Fault-tolerance analysis reveals possible system behavior under the influence of faults. Such analysis is essential for satellites where faults might be caused by space radiation and autonomous recovery is needed. In this paper we present a statistical simulation approach for fault-tolerance analysis of satellite On-Board Computers (OBCs) that are based on Commercial Off-The-Shelf (COTS) components. Since the logic level of COTS electronics is unknown to satellite designers, a new higher-level fault-tolerance analysis is required. We propose such technique that relies on OBC modeling and fault modeling, based on the modeling principle of Single-Event Upsets (SEUs). For the first time we can compare the efficiency of fault-tolerance techniques implemented in software and Field-Programmable Gate Array (FPGA). In addition, our approach enables to analyze system fault-tolerance at early development stages. In a case study the approach is applied to an OBC with a Microsemi SmartFusion SoC, that executes a satellite attitude control algorithm. The gained statistical simulation results enabled 50% reduction in the hardware overhead of the implemented memory scrubbing technique without loss in fault-tolerance. Our method revealed critical fault-tolerance drawbacks of the initial system design that could have lead to satellite mission failure.     

Universal Interface between Functional Oxides and Silicon

Integration of crystalline oxides with silicon provides a versatile platform to extend and advance silicon technology. The interface between oxide and Si controls the structure and functional properties of the resulting material. In particular, the formation of a submonolayer metal phase on silicon is the standard approach to stabilize the epitaxial growth of oxides. However, fundamental questions—a) whether the interface transforms in the process of the synthesis; and b) if it is possible to control the interface and its electronic structure by varying the submonolayer template—remain unanswered. The present study employs MBE synthesis of EuO and SrO on Si(001) to demonstrate that the structure of the oxide/Si interface does not depend on the type of the template, its symmetry, and stoichiometry. Chemical transformations of the templates converging into the same 2D product are detected in situ by electron diffraction. Then, the common interfacial structure of 1D periodicity is visualized by high-resolution electron microscopy. The study provides insights into the process of oxide integration with silicon but also sets the limits in designing oxide/Si interfaces.     

Photonic Side-Channel Analysis of Arbiter PUFs

As intended by its name, physically unclonable functions (PUFs) are considered as an ultimate solution to deal with insecure storage, hardware counterfeiting, and many other security problems. However, many different successful attacks have already revealed vulnerabilities of certain digital intrinsic PUFs. This paper demonstrates that legacy arbiter PUF and its popular extended versions (i.e., feed-forward and XOR-enhanced) can be completely and linearly characterized by means of photonic emission analysis. Our experimental setup is capable of measuring every PUF internal delay with a resolution of 6 ps. Due to this resolution, we indeed require only the theoretical minimum number of linear independent equations (i.e., physical measurements) to directly solve the underlying inhomogeneous linear system. Moreover, it is not required to know the actual PUF responses for our physical delay extraction. We present our practical results for an arbiter PUF implementation on a complex programmable logic device manufactured with a 180 nm process. Finally, we give an insight into photonic emission analysis of arbiter PUF on smaller chip architectures by performing experiments on a field programmable gate array manufactured with a 60 nm process.