An Architecture for Distributed Energies Trading in Byzantine-Based Blockchain

With the development of smart cities, not only are all corners of the city connected to each other, but also connected from city to city. They form a large distributed network together, which can facilitate the integration of distributed energy station (DES) and corresponding smart aggregators. Nevertheless, because of potential security and privacy protection arisen from trustless energies trading, how to make such energies trading goes smoothly is a tricky challenge. In this paper, we propose a blockchain-based multiple energies trading (B-MET) system for secure and efficient energies trading by executing a smart contract we design. Because energies trading requires the blockchain in B-MET system to have high throughput and low latency, we design a new byzantine-based consensus mechanism (BCM) based on node's credit to improve efficiency for the consortium blockchain under the B-MET system. Then, we take combined heat and power (CHP) system as a typical example that provides distributed energies. We quantify their utilities, and model the interactions between aggregators and DESs in a smart city by a novel multi-leader multi-follower Stackelberg game. It is analyzed and solved by reaching Nash equilibrium between aggregators, which reflects the competition between aggregators to purchase energies from DESs. In the end, we conduct plenty of numerical simulations to evaluate and verify our proposed model and algorithms, which demonstrate their correctness and efficiency completely

Coordination and Reactivity in Organosilicon Compounds

The coordination chemistry of silicon in silane-nucleophile interactions is examined by solution NMR spectroscopy ( 29Si, 1H and 13C ) and conductivity measurements for acyclic, simple, multifunctional silanes R4-nSiXn( R = Me, Ph, H; X = F, Cl, Br, I, OSO2CF3; n = 2, 3, 4 ) and a choice of nucleophiles ( Nu = NMI, HMPA, DMAP, DMF, DMPU ). Coordination at silicon involves delicate balance between the steric and electronic effects of all the groups involved. Tetra-, penta- and hexa-coordinated silicon species, neutral or ionic, intermediates or final adducts, are all observed in solution, depending on the number and nature of the leaving and the R groups, the nature and quantities of the nucleophiles. No evidence of heptacoordination is found. The ability to expand coordination at silicon increases with the increasing of the number of electronegative functional groups. The sequence of coordinate capability is SiX4, R'SiX3 (hexa-) > R'2SiX2 (penta-) > R'3SiX (tetra-) when R' = Me, Ph. The nature of the leaving groups does not affect the maximum coordination number of the most stable adduct of a silane but determines the equilibrium constants K, which is in an Older of I > OTf, Br » Cl > F » OR" ( R" = Et, iPr ). The H-containing silanes present a distinct example of the steric effect of the R groups. A replacement of R' by H often increases the maximum coordination number of the most stable silane-nucleophile adducts by one, together with an enhanced reactivity of the silane. The coordinate ability of H-containing silanes is in the order: HSiX3, R'HSiX2, SiX4 (hexa-) > R'2HSiX, R'2SiX2 (penta-) > R'3SiX (tetra-). The coordination at silicon is also determined by the steric hindrance resulting from the nucleophiles, which can be divided into two categories. Nucleophiles of group one with smaller steric hindrance ( NuI = NMI, DMAP, DMF ) usually form silane-NuI complexes with coordination numbers greater by one than those of nucleophiles of group two with larger steric hindrance ( NuII = HMPA, DMPU ). The nucleophilicities of the nucleophiles only contribute to the equilibrium constant K. The competitive processes between association and substitution in the interactions of silanes with nucleophiles result in the coordination at silicon changing with the quantities of the nucleophile presented. A number of reaction mechanisms are suggested. Some of the intermediate complexes are proved less reactive than their parent silanes or adducts to substitution. Me2HSiOTf and MeHSiOTf2 are found to be effective reducing agents for aldehydes and ketones. They are the first simple silanes reported to be promising reducing agents without the presence of a catalyst Factors affecting the reduction are discussed

A Crowdsourcing Approach to Chinese Vocabulary Learning

The fast development of new technology, particularly web-based andmobile technology, has been transforming ways how languages aretaught and learned. The current study examines the use of Memrise, acrowdsourcing spaced repetition program, by college students ofChinese, and its effects on Chinese character learning. The findings ofthe study demonstrate the effectiveness of the program. The study hasalso identified important factors and conditions that should exist inorder for the use of the program to be successful. Based on the findingsof the study, suggestions are made for language teachers in regards tousing Memrise or similar programs in vocabulary teaching. Eventhough the current study focuses on Chinese character learning, thefindings of the study can be applied to any other languages