In an effort to manipulate the bond strengths of hydrogen bonds, we have studied a three-component chemical system consisting of a reaction center, a conjugated bridge, and a hydrogen-bonding site. Protonation of the reaction center triggers intramolecular charge transfer from the hydrogen-bonding site, altering its affinity to bind to an acceptor. Previously, we had found that this communication (signal transduction) between the reaction center and the hydrogen-bonding site does not necessarily die out with increasing length of the conjugated bridge. In certain cases, this signal transduction is maintained-and even amplified-over long distances (I. Chao, T.-S. Hwang, Angew. Chem. 2001, 113, 2775-2777; Angew. Chem. Int. Ed. 2001, 40, 2703-2705). In this study we report the results of an extensive theoretical investigation of this problem to provide insights into this intriguing phenomenon. In the systems we investigated it was found that the push-pull process between the hydrogen-bonding site and the protonatable reaction center was mediated with the greatest facility by conjugated bridges with low-lying pi and pi* orbitals.
The research of rapid decompression with its effect assessment and protection technology is the problem that must be faced by the future exploration projects such as near space exploration, deep space exploration, and long-term lunar or Mars base. A new reusable quick opening mechanism which can be opened in millisecond is designed to meet the testing requirement of ground simulator for extremely rapid decompression, and the testing results show that the quick opening mechanism can be opened within 0.1 s. The mathematical formulation is also developed, and the comparisons with the results from the literature demonstrate its validity. The CFD simulation and the verification system are established for the airflow in the rapid decompression process under different opening degrees. The simulation results show that the effect of the opening on the decompression process is very obvious and the decompression time corresponding to 50%, 75%, and 100% opening is 479.1 ms, 320.7 ms, and 290.1 ms, respectively. The testing results also show a consistent trend which is 583 ms, 450 ms, and 384 ms, respectively, to reach the equilibrium state.
In this paper, the stability of the electrical control system structure of the typical solar simulator system is studied. Volt-ampere characteristic tests, light-on tests and system-level irradiance stability tests after light-on of xenon lamps with three power supplies were carried out using the solar simulator (KFTA). The solar simulator test is carried out on the current three mainstream input power supplies respectively. The stability test target of the electrical control structure of the solar simulator system is completed, and the irradiation instability is realized which is better than± 1%.
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