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991.
992.
Collisional activation spectra have identified (i) as Stable ion structures. Evidence is presented for a variety of pathway for their formation, including anchimeric assistance and hydrogen migration in less stable isomers. The fragmentation behavior of a number of [CnH2n+1O]+ isomers of n = 2 to 5 shows that extensive rearrangements are common, but that some reactions appear to be useful for ion structure elucidation. One reaction identified is unusual in that it represents the decomposition of an even-electron ion to yied an odd-electron ion product in significant abundance.  相似文献   
993.
Rotational-state distributions of the CO+ (A–X, B–X) and N2+(B–X) emissions produced by the collisions of He(2 3S) with CO and N2 were studied in the collision energy (ER range 100–200 meV. The rotational populations of the emitting states can be fitte by single Boltzmann temperatures (TR. The TR (320 ± 30 K) for the ν′ = 3 and 4 levels of the CO+ (A2Π) state are nearly independent of, or slightly increase with, ER, while TR for the CO+(B2Σ+, ν′ = 0) state increases rapidly with ER.The TR (430 ± 20 K) for the N2+(B2Σ+, ν′ = 0) state is nearly independent or slightly decreases with increasing ER. Interactions providing these trends are discussed.  相似文献   
994.
995.
996.
997.
The total synthesis of salinosporamide A has been achieved through enzymatic desymmetrization, diastereoselective aldol reaction, intramolecular aldol reaction, and intermolecular Reformatsky-type reaction followed by 1,4-reduction as key reactions.  相似文献   
998.
Bacterial cold water disease, caused by Flavobacterium psychrophilum, is a serious problem in the aquaculture industry worldwide. Several methods to prevent and treat cold water disease have been studied. Although detection at the early stage of F. psychrophilum infection is very important for the prevention and treatment of cold water disease, an effective detection method has not yet been developed. The use of flow cytometry (FCM) for the rapid determination of bacterial cell numbers with high sensitivity is beginning to attract attention. Immunomagnetic separation (IMS) has also been used to detect F. psychrophilum. The purpose of the present study was to develop a method to quickly determine the number of bacterial cells by combining the FCM and IMS methods. Because samples can be more effectively concentrated using smaller magnetic beads and stronger magnetism, we used carbonyl iron powder as the magnetic beads for the IMS. The detection level of F. psychrophilum using FCM combined with IMS was 5 orders lower than that using FCM without IMS. The values determined using FCM combined with IMS strongly correlated with those obtained using the colony-counting method, in the range of approximately 10–108 colony-forming units per milliliter. One FCM assay could be completed within 60 s and the total assay time, including sample preparation, was less than 2 h. The combined method of FCM with IMS developed in this study can be used reliably for the rapid detection of F. psychrophilum.  相似文献   
999.
1000.
Buffer-gas pressure broadening for the nu(1)+nu(3) band of H(2)O at 1.34-1.44 mum for a variety of buffer gases was investigated at room temperature using continuous-wave cavity ring-down spectroscopy. The effective interaction energy of water dimer under room temperature conditions was evaluated from the pressure broadening coefficients for rare gases using Permenter-Seaver's relation. Monte Carlo simulations were performed using ab initio molecular orbital calculations to evaluate the interaction energies for the water dimer at 300 K. In this theoretical calculation, the orientations of the two water molecules were statistically treated.  相似文献   
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