Plasmonic nanostructures have been widely used for photochemical conversions due to their unique and easy-tuning optical properties in visible and near-infrared range. Compared with the plasmon-generated hot electrons, the hot holes usually have a shorter lifetime, which makes them more difficult to drive redox reactions. This review focuses on the photochemistry driven by the plasmon-generated hot holes. First, we discuss the generation and energy distribution of the plasmon-generated hot carriers, especially hot holes. Then, the dynamics of the hot holes are discussed at the interface between plasmonic metal and semiconductor or adsorbed molecules. Afterwards, the utilization of these hot holes in redox reactions is reviewed on the plasmon-semiconductor heterostructures as well as on the surface of the molecule-adsorbed plasmonic metals. Finally, the remaining challenges and future perspectives in this field are presented. This review will be helpful for further improving the efficiency of the photochemical reactions involving the plasmon-generated hot holes and expanding the applications of these hot holes in varieties of chemical reactions, especially the ones with high conversion rate and selectivity.

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Elastic constants of single carbon fibres were estimated by a novel nanoindentation based method and subsequently predicted by modified two-and three-phase Eshelby-Mori-Tanaka (EMT) micromechanical models which takes into account both crystalline, amorphous phases and microvoids of the fibre structure. This case study was carried out on a T-300 PAN-based carbon fibre reinforced SiC composite material at room temperature. Transversal and longitudinal cross-sections of individual fibres were indented by a sharp Berkovich tip up to the maximum depth of 150 nm. Assuming transverse isotropy of the fibres, their five elastic constants were deduced from the measured indentation moduli using numerical (Vlassak-Nix) and analytical

We synthesize periodic copolymers possessing [ABAC], [ABCD], and [ABCDBCAD] repeating structure by radical addition-coupling polymerization (RACP) based on the reaction between α,ω-biradicals derived from α,α 0 -dibromo compound and 2-methyl-2-nitrosopropane.

The term łsmart contractsž has become ubiquitous to describe an enormous number of programs uploaded to the popular Ethereum blockchain system. Despite rapid growth of the smart contract ecosystem, errors and exploitations have been constantly reported from online contract systems, which has put financial stability at risk with losses totaling millions of US dollars. Most existing research focuses on pinpointing specific types of vulnerabilities using known patterns. However, due to the lack of awareness of the inherent nondeterminism in the Ethereum blockchain system and how it affects the funds transfer of smart contracts, there can be unknown vulnerabilities that may be exploited by attackers to access numerous online smart contracts. In this paper, we introduce a methodical approach to understanding the inherent nondeterminism in the Ethereum blockchain system and its (unwanted) influence on contract payments. We show that our new focus on nondeterminism-related smart contract payment bugs captures the root causes of many common vulnerabilities without relying on any known patterns and also encompasses recently disclosed issues that are not handled by existing research. To do so, we introduce techniques to systematically model components in the contract execution context and to expose various nondeterministic factors that are not yet fully understood. We further study how these nondeterministic factors impact contract funds transfer using information flow tracking. The technical challenge of detecting nondeterministic payments lies in discovering the contract global variables subtly affected by read-write hazards because of unpredictable transaction scheduling and external callee behavior. We show how to augment and instrument a contract program into a representation that simulates the execution of a large subset of the contract behavior. The instrumented code is then analyzed to flag nondeterministic global variables using off-the-shelf model checkers. We implement the proposed techniques as a practical tool named NPChecker (Nondeterministic Payment Checker) and evaluate it on 30K online contracts (3,075 distinct) collected from the Ethereum mainnet. NPChecker has successfully detected nondeterministic payments in 1,111 online contracts with reasonable cost. Further investigation reports high precision of NPChecker (only four false positives in a manual study of 50 contracts). We also show that NPChecker unveils contracts vulnerable to recently-disclosed attack vectors. NPChecker can identify all six new vulnerabilities or variants of common smart contract vulnerabilities that are missed by existing research relying on a łcontract vulnerability checklist. ž CCS Concepts: • Software and its engineering → General programming languages.

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