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A cross-flow jet type singlet oxygen generator is developed, tested and analyzed in order to characterize the dependence of output performance on major input parameters. Details of the analysis are provided and the results of the study will be useful for upgrading the existing models.

A new twisted aerosol singlet oxygen generator (TA-SOG) was created for supersonic chemical oxygen-iodine laser. The new TA-SOG can be operated at an internal gas velocity of 85 m/s. Such operational ability is three times higher than that of the jet-type SOG. A deviation was noted between predicted results and experimental results which can be attributed to the macroscopic mass transfer of H2O ions and the rise of the real specific surface.

Feedback control system was constructed, in which the intensity of the magnetic field applied to the laser medium varied automatically in response to the laser power fluctuation, and used to demonstrate the output power stabilization for a chemical oxygen-iodine laser. A theoretical analysis of the input/output characteristics of the feedback system was performed and was observed to be in agreement with experimental results. The response time of the system was also found to be as short as 1 ms limited by the applied voltage of the electromagnet.

Background: Early recurrences of atrial arrhythmias (ERAAs) after ablation may require therapeutic intervention. The optimal medical therapy that prevents ERAAs requires clarification. This study aimed to compare the incidence of ERAAs between patients who received or did not receive bisoprolol transdermal patches (BTPs) at 3 months postablation. Methods: This single‐center retrospective study enrolled 203 consecutive patients with paroxysmal atrial fibrillation (AF) who had undergone their first ablation, comprising 59 in the BTP group and 144 in the non‐BTP group. Follow‐up assessments were conducted monthly for 3 months. We evaluated the incidence of ERAAs. Results: During the initial 1‐week observational period, the rate of ERAAs was lower in the BTP group (5.0%) than that in the non‐BTP group (18.8%) (P =.013). At 3 months postablation, the rate of ERAAs was lower in the BTP group (6.8%) than that in the non‐BTP group (25.7%) (P =.002). The cumulative freedom from ERAAs was significantly lower in the BTP group than in the non‐BTP group (log‐rank: P =.003). Administering BTPs was an independent factor that protected against ERAAs (odds ratio 0.181, [95% confidence interval 0.059‐0.559], P =.003). Conclusion: BTPs may prevent ERAAs after ablation. [ABSTRACT FROM AUTHOR]

A quasi-two-dimensional model has been developed to predict the performance of a crossflow jet singlet oxygen generator. The model takes into account HO2- depletion, gas temperature variation due to the pooling deactivation of O2(1Δ), and the stretch effect of gas/liquid interaction area due to the jet-induced pressure loss. The modeling results compare favorably with the test data measured over a wide range of geometries and operation conditions. The overall agreements between measured and calculated values in terms of root-mean-square errors for utilization, yield, and gas temperature are 0.030, 0.035, and 16.23 K, respectively. [ABSTRACT FROM AUTHOR]

Presents a study that investigated the effects of fluorine donor additives and initiation level on hydrogen fluoride chemical lasers. Methodology; Analysis of the output characteristics of the laser; Measurement of the laser energy.

Presents a study that described the performance characteristics of a closed-cycle subsonic carrier wave carbon monoxide laser. Methodology; Evaluation of the discharge characteristics of the laser; Examination of the output performance of the laser.

Describes a kinetic model of electron-beam-excited krypton fluoride (KrF) lasers which puts into consideration the vibrational relaxation process. Reason for the decrease in efficiency of KrF lasers; List of KrF kinetic rate constants used in the model; Information on previous models of Krf lasers.

An optical resonator simulation code based on the idea of a partially coherent optical field has been developed and used to optimize the design parameters of an unstable resonator with a stable core. The resonator was intended for use with low-gain, large-bore lasers, such as the chemical oxygen-iodine laser (COIL). First the design parameters of the resonator were optimized by the simulation code; then a set of mirrors was fabricated for a small-scale COIL. A 14-W output with [M.sup.2] = 29 was obtained. The experimentally obtained results were in good agreement with calculations.

Scaling of a CO laser device of closed-cycle self-sustained discharge-excited type has permitted the attainment of a maximum output power of 3.1 kW. The device incorporates two heat exchangers, operating, respectively, on freon R502 and liquid nitrogen. This permits regulation of the working gas temperature to any given level between room temperature and 120 K. [ABSTRACT FROM AUTHOR]

Studies the high-pressure, high-efficiency operation of a chemical oxygen-iodine laser. Direct utilization in the laser cavity of singlet delta oxygen generated by a liquid-type singlet oxygen generator; Ratio of excited iodine to the ground state iodine after dissociation; Laser output as a function of mirror transmittance.

Design and performance characteristics of a closed-cycle subsonic cw CO laser excited by a transverse self-sustained dc glow discharge are described. The maximum laser output power obtained to date is 380 W or 950 W per meter of discharge length, corresponding electrical conversion efficiency and specific output energy being 10.2% and 64.7 J/g, respectively. [ABSTRACT FROM AUTHOR]

Optical power transmission of 5-μm band CO laser beam through As2S3 glass core Teflon fluorinated ethylene propylene clad fibers is described. The maximum transmitted power is as high as 62 W with a 700-μm core diameter fiber, which corresponds to a power intensity of 16 kW/cm2 at the fiber output end. The influence of fiber bending on the transmission characteristics is also reported. [ABSTRACT FROM AUTHOR]

Atmospheric pressure operation of a KrF laser pumped by 50-ns electron beams was experimentally investigated. For a 1-atm mixture of Kr and F2 without diluent, a specific output energy of 4.2 J/1 was obtained at 1.7-MW/cm3 excitation rate. Under this condition the intrinsic efficiency was about 5% (6% was maximum at 20% Kr in argon diluent) which was comparable to that from 1-atm normal (10% Kr) mixtures. [ABSTRACT FROM AUTHOR]

The output performance of the electron-beam-excited KrF laser operating at one atmosphere is theoretically analyzed because the KrF laser at one atmosphere can greatly reduce the design constraints on the large laser windows and the electron-beam pressure foils in a huge laser system as the inertial confinement fusion energy driver. The KrF laser using the atmospheric pressure, argon-free laser mixture is found to operate with an intrinsic laser efficiency as high as that of high-pressure, aregon-diluted mixtures. This is because three-body collisional quenching is not a detrimental energy-loss channel for the atmospheric pressure operation. By using higher excitation rate and shorter excitation pulse width pumping, higher intrinsic laser efficiency than conventional, argon-diluted, high-pressure mixtures is found to be attainable. Moreover, the specific laser energy (28 J/l, for 1-atm Kr/F2 mixtures pumped by an electron beam of 100 ns, 600 keV, and 150 A/cm2) is comparable to that of two-atm, argon-rich laser gas mixtures under the same excitation condition. [ABSTRACT FROM AUTHOR]

A resonator using w-axicon and axicon mirrors for a double coaxial electrode discharge CO2 laser is analyzed using the vector field, iterative reflection method. A uniform ring-shaped output mode is expected even with struts in the electrode in the multi kW scheme. [ABSTRACT FROM AUTHOR]

We report on a compact trace nitrogen dioxide (NO2) detector based on cavity ringdown spectroscopy (CRDS), using a passively locked external cavity diode laser (PLEC-DL) in the visible wavelength region. Tailoring the spatial mode matching conditions of an antireflection (AR)-coated diode laser with a high finesse external cavity for effective optical feedback into the DL allows for stable resonant enhancement in the external cavity without any electric feedback apparatus. The external cavity having a finesse in excess of 1.4×105 acts as a ringdown cavity with an effective optical volume (i.e., detection volume) of less than 1 cm3. We successfully demonstrated a noise equivalent absorption loss of 1.4×10-8 cm-1, corresponding to a detection limit of 40 ppb NO2 concentration with a very compact configuration. For differential absorption CRDS, we realized a dual wavelength-locked PLEC-DL in an external cavity simultaneously. Measurements of various NO2 concentrations in N2 based on differential absorption CRDS were performed. [ABSTRACT FROM AUTHOR]

Nozzle banks for an ejector chemical oxygen–iodine laser consisting of two-dimensional slit nozzles with a trip-jet mixing system were tested in the cold- and hot-flow operation regimes. Horizontal Pitot scan experiments demonstrated that the mixing ability of the trips is excellent. The Mach number of the mixed flow was approximately 3. Gain measurements were conducted, and the results of these measurements revealed that the maximum gain was approximately 0.54 m-1. The gain cut off length exceeded 200 mm. Lasing experiments were also conducted, and the power was approximately 3 kW at a chemical efficiency of approximately 18%. [ABSTRACT FROM AUTHOR]