Detection and analysis of new bands of O3 by CRDS between 6500 and 7300 cm

The absorption spectrum of the ¹⁶O₃ isotopologue of ozone has been recorded in the 7000-7920 cm⁻¹ region by high sensitivity CW-Cavity Ring Down Spectroscopy. This report is devoted to the analyses of the 7065-7300 cm⁻¹ region dominated by the ν₁ + 2ν₂ + 5ν₃ and ν₁ + 5ν₂ + 3ν₃ A-type bands at 7130.8 and 7286.8 cm⁻¹ respectively. 289 transitions were assigned to the ν₁ + 2ν₂ + 5ν₃ band. The corresponding line positions were modeled with an effective Hamiltonian involving Coriolis resonance interactions between the (1 2 5) upper state and the (4 4 0), (0 2 6) and (6 1 0) dark states, and an anharmonic resonance interaction with the (2 0 5) state. The very strong interaction (up to 50% mixing of the wavefunctions) between the (1 2 5) and (6 1 0) states leads to the observation of two extra lines of the 6ν₁ + ν₂ band due to a resonance intensity transfer. 213 transitions of the ν₁ + 5ν₂ + 3ν₃ band were assigned and modeled taking into account a Coriolis resonance interaction with the (3 6 0) state.We take the opportunity of the present work to report the analysis of the very weak 4ν₂ + 4ν₃ B-type band at 6506.1 cm⁻¹ which was assigned from previously recorded CRDS spectra. 286 transitions were modeled using the effective Hamiltonian approach.The dipole transition moment parameters of the three analyzed bands were determined by a least-squares fit to the measured line intensities. For the three studied band systems, the effective Hamiltonian and transition moment operator parameters were used to generate line lists provided as Supplementary Materials.     

Photophysical property of rhodamine-cored poly(amidoamine) dendrimers: Simultaneous effect of spirolactam ring-opening and PET process on sensing trivalent chromium ion

Two novel poly(amidoamine) (PAMAM) dendrimers, comprising rhodamine B unit in the core and 1-phenyl-3-methyl-5-pyrazolone unit at the periphery, have been synthesized and characterized. Both dendrimers displayed high selectivity and sensitivity towards Cr³⁺ ion. As considering the potential of being applied as fluorescent sensors for Cr³⁺ ion, we studied the complexes formed between the dendrimers and Cr³⁺ ion. Different PAMAM dendrimers had different recognition mechanism towards Cr³⁺ ion. For dendrimer G2, the recognition of Cr³⁺ was mainly due to the ring-opening of spirolactam. However, it significantly depended on the simultaneous effect of ring-opening of spirolactam and photoinduced electron transfer (PET) in the case of dendrimer G3.     

Photonic crystal based cross connect filters

We propose optical cross connect filters using photonic crystal ring resonators coupled waveguide crossings. We investigate the properties of this component numerically by using the finite-difference time-domain method. Our simulations reveal that the photonic crystal based cross connect filter has more than 92% normalized transmission. Extending our concept for cross connection applications, we demonstrate a 1 × 2 PC-based cross connect filter which utilizes a heterostructure. In this filter, at the resonance of each ring resonator, the normalized power transferred to the related waveguide of the two drop waveguides is found to be more than 91%.     

Numerical analysis of the output power of the injection-locked cw Ti:sapphire lasers

The optimization analysis of the output power of the injection-locked cw Ti:sapphire lasers is presented based on the fact that the injection-locked and free-running lasers almost have the same maximum output power. With the modified Ti:sapphire laser model, the dependences of the threshold and slope efficiency on the ring cavity and crystal parameters are studied through the numerical calculations, which clarify the roles of various parameters in affecting the output power. Our calculated results are in good agreement with the reported experimental data for the laser at 756 nm. Therefore our numerically calculated results could be used as a guideline for designing and optimizing such kind of the lasers.     

Complex-number asymmetry parameters of the optical Fano effect in ring resonators

We studied the sharp asymmetric Fano line shape in fiber ring resonator systems and provided an explicit expression for asymmetry parameters using the physical parameters of the system. The fiber ring system was controllable and reconfigurable, allowing us to produce a variety of Fano line shapes in different configurations. Experimentally observed asymmetric spectral structures were fully reproduced using the complex-number asymmetry parameters, validating the approximations used to reduce the analytical expression for the line shape to the phenomenological Fano formula. The results may be useful in the design of on-chip application systems.     

The uniqueness property for networks with several origin–destination pairs

We consider congestion games on networks with nonatomic users and user-specific costs. We are interested in the uniqueness property defined by Milchtaich (2005) as the uniqueness of equilibrium flows for all assignments of strictly increasing cost functions. He settled the case with two-terminal networks. As a corollary of his result, it is possible to prove that some other networks have the uniqueness property as well by adding common fictitious origin and destination. In the present work, we find a necessary condition for networks with several origin–destination pairs to have the uniqueness property in terms of excluded minors or subgraphs. As a key result, we characterize completely bidirectional rings for which the uniqueness property holds: it holds precisely for nine networks and those obtained from them by elementary operations. For other bidirectional rings, we exhibit affine cost functions yielding to two distinct equilibrium flows. Related results are also proven. For instance, we characterize networks having the uniqueness property for any choice of origin–destination pairs.     

Acid-catalyzed rearrangement of 3-(β-2-aminostyryl)quinoxalin-2(1H)ones—a new and efficient method for the synthesis of 2-benzimidazol-2-ylquinolines

A highly efficient, one-step, versatile method for the synthesis of 2-benzimidazol-2-ylquinolines has been developed on the basis of an acid-catalyzed rearrangement proceeding via a novel ring contraction of 3-(β-2-aminostyryl)quinoxalin-2(1H)ones.     

Ring Enlargement of Alkaloids

Previouspublications'fromourlaboratoryhadreportedtheringenlargementreactionofquatemaryarnrnoniumsaltSofN-methyl-tetTahydroisoquinolinefollowedbyreductivedecyanationwiththenetresuItoftheinserti0nofanextraCH2group,assh0wninSckemeI.ThemethodologyfailedwithsomenatUrallyoccurringalkaloidssuchascephalotaxineandatropine'.Onereasonisthatsomeofthequaternaryammoniumsaltsaredifficulttoprepare,theotheroneisthatsome0fthequaternaryafnmoniumsaItsunderwentHofinarineliminationorSofnmeletrearrangement'.But…     

Conjugacy Classes and Invariant Subrings of R-Automorphisms of R[x]

We consider the group G of R-automorphisms of the polynomial ring R[x] in the case where the ring R has nonzero nilpotent elements. Little is known about G in this case, and because of the importance of G in understanding questions involving the polynomial ring R[x], we initiate here several lines of investigation. We do this by examining in detail examples involving the ring of integers modulo n. If R is a local ring with maximal ideal m such that R/m = ?₂ and m ² = (0), we describe more explicitly the structure of G and determine all rings of invariants of R[x] with respect to subgroups of G.     

One-pot synthesis of new aza- and diaza-aminophenanthrenes

The synthesis of a series of benzo(iso)quinoline and phenanthroline derivatives has been achieved using an efficient one-pot procedure. It proceeds through a Suzuki-Miyaura cross-coupling followed by a Dieckmann-Thorpe ring closure under microwave irradiation and provides easy access to building blocks not readily available through other methods.