Professor LIU YouCheng is a pioneer of free radical chemistry in China. Born in Shu-cheng, Anhui Province in 1920, he received his undergraduate education at the National Central University, China and studied as a gra...Professor LIU YouCheng is a pioneer of free radical chemistry in China. Born in Shu-cheng, Anhui Province in 1920, he received his undergraduate education at the National Central University, China and studied as a graduate student on a scholarship from展开更多
Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP,1a-1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies dem...Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP,1a-1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies demonstrate that photoinduced singlet electron transfer from 1,4-DHP to molecular oxygen occurs. The generated superoxide radical anion (O2-·) is responsible for this typical photochemical oxidation.展开更多
Imine-bridged TTF-π-pyridine derivatives, 2NTTF, 3NTTF and 4NTTF, were synthesized and the cation-binding study was performed. It is noted that with the addition of the micromolar concentration of Pb2+ to the solutio...Imine-bridged TTF-π-pyridine derivatives, 2NTTF, 3NTTF and 4NTTF, were synthesized and the cation-binding study was performed. It is noted that with the addition of the micromolar concentration of Pb2+ to the solution, these compounds display remarkable changes in solution color, 1H NMR spectra and electrochemical properties. The nitrogen atom of the imine-bridge in 2NTTF not only serves as a π-conjugated spacer but also participates in the sensing and coordinating properties.展开更多
With high association constants in nonpolar solvents, the quadruple hydrogen bonding arrays of 2-ureido-4[1H]-pyrimidinones are recently considered to be one of the ideal building blocks to construct the complicated a...With high association constants in nonpolar solvents, the quadruple hydrogen bonding arrays of 2-ureido-4[1H]-pyrimidinones are recently considered to be one of the ideal building blocks to construct the complicated and functional supramole- cular systems. In this paper, we review the latest achievements of the supramolecular assemblies based on 2-ureido-4[1H]-pyrimidinone AADD quad- ruple hydrogen bonding building blocks.展开更多
Frequency response is one of the most important characteristics of photodiode (PD). The upper limitation of the bandwidth of a PD is determined by its intrinsic frequency response. Based on the extraction method to ex...Frequency response is one of the most important characteristics of photodiode (PD). The upper limitation of the bandwidth of a PD is determined by its intrinsic frequency response. Based on the extraction method to extract the intrinsic frequency response,we take a further study to analyze the impact of the reverse bias voltage and the temperature on the frequency response of PDs. With the help of physical model,the experimental data and fitted results based on the reverse bias voltage and temperature separately are discussed,then the most reliable intrinsic frequency response of a PD is obtained.展开更多
文摘Professor LIU YouCheng is a pioneer of free radical chemistry in China. Born in Shu-cheng, Anhui Province in 1920, he received his undergraduate education at the National Central University, China and studied as a graduate student on a scholarship from
基金supported by the National Natural Science Foundation of China (20732007,20972171,50973125)the Ministry of Science and Technology of China (G2007CB808004,2009CB2 20008),and the Bureau for Basic Research of the Chinese Academy of Sciences
文摘Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP,1a-1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies demonstrate that photoinduced singlet electron transfer from 1,4-DHP to molecular oxygen occurs. The generated superoxide radical anion (O2-·) is responsible for this typical photochemical oxidation.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20732007, 20728506 & 20672122)the Ministry of Science and Technology of China (Grant Nos. 2006CB806105, 2007CB808004, 2007CB936001 & 2009CB- 22008)the Bureau for Basic Research of the Chinese Academy of Sciences
文摘Imine-bridged TTF-π-pyridine derivatives, 2NTTF, 3NTTF and 4NTTF, were synthesized and the cation-binding study was performed. It is noted that with the addition of the micromolar concentration of Pb2+ to the solution, these compounds display remarkable changes in solution color, 1H NMR spectra and electrochemical properties. The nitrogen atom of the imine-bridge in 2NTTF not only serves as a π-conjugated spacer but also participates in the sensing and coordinating properties.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20125207,20272066,20333080)the Ministry of Science and Technology of China(Grant No.2003CB716802).
文摘With high association constants in nonpolar solvents, the quadruple hydrogen bonding arrays of 2-ureido-4[1H]-pyrimidinones are recently considered to be one of the ideal building blocks to construct the complicated and functional supramole- cular systems. In this paper, we review the latest achievements of the supramolecular assemblies based on 2-ureido-4[1H]-pyrimidinone AADD quad- ruple hydrogen bonding building blocks.
基金supported by the National Natural Science Foundation of China (60820106004, 60536010, 60777029 and 60837001)National Program on Key Basic Research Program of China (G2006CB604902 and G2006CB302806)+1 种基金National High Technology Research and Development Program of China (2009AA03Z409)Major International Cooperation Projects of China (2006dfa11880)
文摘Frequency response is one of the most important characteristics of photodiode (PD). The upper limitation of the bandwidth of a PD is determined by its intrinsic frequency response. Based on the extraction method to extract the intrinsic frequency response,we take a further study to analyze the impact of the reverse bias voltage and the temperature on the frequency response of PDs. With the help of physical model,the experimental data and fitted results based on the reverse bias voltage and temperature separately are discussed,then the most reliable intrinsic frequency response of a PD is obtained.
