选择同轴电缆和双绞线

因其性能的限制,铜缆的应用几次走到了尽头。之后,新工艺和元件的推出又使它得到了重生。对于两种最常用的高性能铜缆,同轴电缆和双绞线理论上是有局限性的,然而,我们离这些极限有多近呢？     

Redox State of Iron and Its Related Effects in the CaO–P2O5–Fe2O3 Glasses

Iron exists in Fe²⁺ and Fe³⁺ states in CaO–P₂O₅–Fe₂O₃ glasses and they impart characteristic optical absorption bands that allow analysis of relative proportion of the two species. This communication reports the redox states of glasses melted under air, argon, and oxygen atmospheres and relates them to the dissolution rates. The dissolution rate was found to be related to the redox state and it is lowered if the glass is melted under oxidizing atmospheres.     

Molecular Interactions of Tannic Acid with Proteins Associated with SARS-CoV-2 Infectivity

The overall impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on our society is unprecedented. The identification of small natural ligands that could prevent the entry and/or replication of the coronavirus remains a pertinent approach to fight the coronavirus disease (COVID-19) pandemic. Previously, we showed that the phenolic compounds corilagin and 1,3,6-tri-O-galloyl-β-D-glucose (TGG) inhibit the interaction between the SARS-CoV-2 spike protein receptor binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 target receptor on the cell membrane of the host organism. Building on these promising results, we now assess the effects of these phenolic ligands on two other crucial targets involved in SARS-CoV-2 cell entry and replication, respectively: transmembrane protease serine 2 (TMPRSS2) and 3-chymotrypsin like protease (3CLpro) inhibitors. Since corilagin, TGG, and tannic acid (TA) share many physicochemical and structural properties, we investigate the binding of TA to these targets. In this work, a combination of experimental methods (biochemical inhibition assays, surface plasmon resonance, and quartz crystal microbalance with dissipation monitoring) confirms the potential role of TA in the prevention of SARS-CoV-2 infectivity through the inhibition of extracellular RBD/ACE2 interactions and TMPRSS2 and 3CLpro activity. Moreover, molecular docking prediction followed by dynamic simulation and molecular mechanics Poisson–Boltzmann surface area (MMPBSA) free energy calculation also shows that TA binds to RBD, TMPRSS2, and 3CLpro with higher affinities than TGG and corilagin. Overall, these results suggest that naturally occurring TA is a promising candidate to prevent and inhibit the infectivity of SARS-CoV-2.     

Fuel choice and aggregate energy demand in the residential and commercial sectors

The energy demand response of the residential and commercial sectors to fuel price changes is of increasing importance to public policy makers. In this paper, the demands for energy in both sectors are examined separately using a refined data base. For each sector, a multinomial logit formulation is utilized, along with an aggregate demand equation to determine analytically short- and long-run fuel price elasticities of demand for the major fuels consumed. It is found that increases in energy prices have a greater effect on energy demand in the commercial sector. Furthermore, in both sectors, raising electricity prices has a greater effect for conserving energy (both end-use and primary) than do equal price rises for natural gas or heating oils.     

Simulation of driver fatigue monitoring via blink rate detection,using 65 nm CMOS technology

This paper proposes a system to detect and measure blink rate to determine fatigue levels. The method involved analysing specific frames to determine that a blink occurred, and then monitoring the time between successive blinks. The program was simulated in python using a Raspberry Pi Zero and a standard USB camera. For the blink rate detection block, a gate level schematic was implemented in Cadence software using 65 nm CMOS technology. The design was based around an asynchronous 6-bit based edge counter which was designed using D-flip-flops. The simulation calculated the average blink rate and compared this to the most recent blink rate. The outcome would determine if an alarm signal should be sent to the alarm. The system consumed 130 μA from a 1.2 V power supply.     

Failure mechanisms in polyolefines: The role of crazing, shear yielding and the entanglement network

Macroscopic deformation and failure modes of polyolefines are reviewed in terms of deformation and failure models based on the craze initiation and propagation model of Kramer-Berger and the craze-crack transition model of Kramer-Brown. Although these models were formulated for amorphous polymers they are also valid for semi-crystalline polymers. The important role of the underlying molecular entanglement network in this approach is reflected by the strain hardening behaviour which is shown to be a robust measure for predicting slow crack growth performance. The polymer network response explains the experimentally observed presence of two Brittle-Ductile transitions, one at low temperature or high strain rates, linked with chain scission which dominates crazing, the other at elevated temperatures or low strain rates which involves disentanglement crazing. The relation between these two Brittle-Ductile transitions and the major transition temperatures for molecular mobility such as the glass transition and the crystal α relaxation temperature are discussed. Valid strategies for increasing the crack propagation resistance in polyolefines are reviewed. Finally an outlook for further research to complement the present knowledge base is formulated.