Miniaturization limits of field-effect based MEMS accelerometers

Accelerometers are increasingly gaining in importance in the consumer electronics sector. To estimate whether field-effect based accelerometers have an advantage over sensor types common today, we analyze their scaling performance in this paper. Within the scope of this research, firstly we create an analytical model and subsequently verify it by numerical simulation. Based thereon, a numerical–analytical study of the scaling performance follows. The requirements are based on a commercially available capacitive accelerometer. We identify the main miniaturization limits of field-effect based accelerometers, which are total noise and pull-in effect. Those limits lead to a total area estimation for a triaxial MEMS accelerometer core of only 410 μm × 300 μm.     

Dynamic Trust Management

Trust management forms the basis for communicating policy among system elements and demands credential checking for access to all virtual private service resources—along with careful evaluation of credentials against specified policies—before a party can be trusted.     

Love wave immunosensor for antibody recognition using an innovative semicarbazide surface functionalization

A new novel and easy functionalization route of a Love wave acoustic sensor based on the α-oxo-semicarbazone bond is described. The interest is firstly to observe in real-time the immobilization of the peptide on the semicarbazide surface of the transducer and secondly to monitor the specific binding of antibodies. Site-specific immobilization of antigenic-peptides as well as binding of murine monoclonal antibodies has been shown by gravimetric measurements. A tetramethylrhodamine-labeled goat antibody directed against murine antibodies was used to further characterize the biomolecular interactions by fluorescence microscopy and surface analysis (by AFM). Our data show that the gravimetric monitoring developed from the prepared Love wave immunosensor is a promising alternative route to characterize chemical and biomolecular events.     

Porous Permeable Polymers

Features of extrusion for mixtures of polyvinyl chloride and a pore-forming agent with the aim of preparing very porous materials are studied. It is shown that extrusion rate depends on the particle size of the pore-forming agent with the same volume content. This is explained by the difference in the structure of mixtures with respect to pore-forming agent. Marked anisotropy is established for the porous structure of materials in the extrusion direction and perpendicular to it. The hydraulic and mechanical properties of porous materials are determined and possible fields for their application (aeration in fish breeding, capillary transport for under-root irrigation, etc.) are suggested.     

A carbonate-free,sulfone-based electrolyte for high-voltage Li-ion batteries

Practical implementation of next-generation Li-ion battery chemistries is to a large extent obstructed by the absence of an electrolyte that is capable of simultaneously supporting reversible electrochemical reactions at two extreme electrochemical potentials—above 4.5?V at the positive electrode and near 0?V vs. Li at the negative electrode. Electrolytes based on carbonate esters have been reliable in satisfying state-of-the-art Li-ion battery (LIB) chemistries below <4.2?V; however, it is the intrinsic thermodynamic tendency of these carbonates to decompose at potentials well below the thermodynamic threshold required for reversible reactions of high-voltage systems (>4.4?V), releasing CO₂. In this work, we explore a carbonate-free electrolyte system based on a single sulfone solvent, in which a newly discovered synergy between solvent and salt simultaneously addresses the interfacial requirements of both graphitic anode and high-voltage cathode (LiNi_0.5Mn_1.5O₄ (LNMO)). Experimental measurements, quantum chemistry (QC) calculations, and molecular dynamics simulations reveal the system’s fast ion conduction, stability over a wide temperature range, and non-flammability. At the anode, a LiF-rich interphase generated by early-onset reduction of the salt anion effectively suppresses solvent co-intercalation and subsequent graphite exfoliation, enabling unprecedented and highly reversible graphite cycling in a pure sulfone system. Under oxidative conditions, QC calculations predict that high salt concentration promotes complex/aggregate formation which slow the decomposition of sulfolane and leads to polymerizable rather than gaseous products—a fundamental improvement over carbonate solvents. These predictions are corroborated by X-ray photoelectron spectroscopy (XPS), cryogenic-transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS) experiments, which revealed the presence of a thin, conformal, sulfur-based cathode electrolyte interphase (CEI). Together, the functional interphases (SEI/CEI) generated by this electrolyte system supported long term operation of a high-voltage (4.85?V) LNMO/graphite full cell, which retained ～70% of its original first-cycle discharge capacity after the 1000th cycle. Based on these results, this new carbonate-free electrolyte system, supported by the mechanistic understanding of its behavior, presents a promising new direction toward unlocking the potential of next generation Li-ion battery electrodes.     

Anisotropy of acousto–optic figure of merit in lithium tetraborate crystals

We analyse anisotropy of acousto–optic figure of merit (AOFM) for Li₂B₄O₇ crystals in order to estimate the prospects of these crystals in acousto–optics. We find that the maximal AOFM, 3.44 × 10^?15 s³/kg, is peculiar for the isotropic acousto–optic interaction of the incident ordinary optical wave with the quasi-longitudinal acoustic wave. For the case of anisotropic diffraction in Li₂B₄O₇, the maximum 1.87 × 10^?15 s³/kg can be reached using the interaction of the extraordinary optical wave with the quasi-longitudinal acoustic wave. The case of collinear diffraction is characterized by small AOFMs, with the largest value 0.26 × 10^?15 s³/kg.     

Orientation-controlled,low-temperature plasma growth and applications of h-BN nanosheets

Nano Research - Dimensionality and orientation of hexagonal boron nitride (h-BN) nanosheets are promising to create and control their unique properties for diverse applications. However,...     

Computational Analysis of Run-time Monitoring: Fundamentals of Java-MaC

A run-time monitor shares computational resources, such as memory and CPU time, with the target program. Furthermore, heavy computation performed by a monitor for checking target program's execution with respect to requirement properties can be a bottleneck to the target program's execution. Therefore, computational characteristics of run-time monitoring cause a significant impact on the target program's execution.We investigate computational issues on run-time monitoring. The first issue is the power of run-time monitoring. In other words, we study the class of properties run-time monitoring can evaluate. The second issue is computational complexity of evaluating properties written in process algebraic language. Third, we discuss sound abstraction of the target program's execution, which does not change the result of property evaluation. This abstraction can be used as a technique to reduce monitoring overhead. Theoretical understanding obtained from these issues affects the implementation of Java-MaC, a toolset for the run-time monitoring and checking of Java programs. Finally, we demonstrate the abstraction-based overhead reduction technique implemented in Java-MaC through a case study.     

PatrIoT: practical and agile threat research for IoT

The Internet of things (IoT) products, which have been widely adopted, still pose challenges in the modern cybersecurity landscape. Many IoT devices are resource-constrained and almost constantly online. Furthermore, the security features of these devices are less often of concern, and fewer methods, standards, and guidelines are available for testing them. Although a few approaches are available to assess the security posture of IoT products, the ones in use are mostly based on traditional non-IoT-focused techniques and generally lack the attackers’ perspective. This study provides a four-stage IoT vulnerability research methodology built on top of four key elements: logical attack surface decomposition, compilation of top 100 weaknesses, lightweight risk scoring, and step-by-step penetration testing guidelines. Our proposed methodology is evaluated with multiple IoT products. The results indicate that PatrIoT allows cyber security practitioners without much experience to advance vulnerability research activities quickly and reduces the risk of critical IoT penetration testing steps being overlooked.