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A numerical simulation on the spray-type dielectric barrier discharge (DBD) is carried out for a mixture gas of nitrogen ([N.sub.2]) and sulfur hexafluoride (S[F.sub.6]) at atmospheric pressure to understand the electrical characteristics and the plasma flow dynamics that depend on design parameters and operating conditions. A 2-D axi-symmetric nonuniform grid is employed in the simulation code consisting of the following three numerical modules: 1) discharge module; 2) flow module; and 3) reaction calculation module. Through the coupling of these modules, the discharge and plasma flow characteristics are interactively calculated for discharge properties and behaviors of charged and neutral particles in the [N.sub.2]/S[F.sub.6] plasma, including 26 species interacting among them by 59 reactions. As a result of numerical simulations, the effects of the spray hole and the gas flow on the plasma flow characteristics are discussed in the spray-type DBD reactor. The existence of a spray hole in the grounded barrier/electrode plate induces strong electric fields along the spray hole barrier wall, and these high fields trigger a localized discharge similar to the surface discharge. The localized discharge spreads out in the discharge region toward the powered electrode barrier and gives the discharge current a pulsed shape according to the group behavior of a high-density electron to eventually produce a high-density fluorine atom in both the spray hole and spray regions. When the spray hole radius decreases, the fluctuations of hole-induced electric field also decreases, accompanied by the reduced production of average densities of the electron and the fluorine atom. However, the reduced spray hole size enhances the advective velocity along the hole axis, and therefore, the overall fluorine atom density over the substrate surface is increased. With increasing inlet gas flow velocity, the localized discharges occur more frequently because of electric potential formation by interacting among meta-stable species and ions to enhance the fluorine atom production. The fast advective velocity also enlarges the radial distributions of effluent rate and fluorine atom density in the spray region and on the substrate surface due to the transport of neutral particles. Index Terms--Atmospheric pressure nitrogen ([N.sub.2]) and sulfur hexafluoride (S[F.sub.6]) plasma, numerical simulation, plasma flow effect, spray-type dielectric barrier discharge (DBD).

A method to eliminate the narrow unstable region of a symmetric two-rod resonator with a 90 degrees optical rotator that is used to compensate for thermal birefringence of the laser rod is proposed. Also, the effect of the distance between the two rods of the proposed resonator on the stability and the beam quality is investigated.

Charcot‐Marie‐Tooth disease (CMT) and related diseases are a genetically and clinically heterogeneous group of peripheral neuropathies. Particularly, mutations in several aminoacyl‐tRNA synthetase (ARS) genes have been reported to cause axonal CMT (CMT2) or distal hereditary motor neuropathy (dHMN). However, the common pathogenesis among CMT subtypes by different ARS gene defects is not well understood. This study was performed to investigate ARS gene mutations in a CMT cohort of 710 Korean families. Whole‐exome sequencing was applied to 710 CMT patients who were negative for PMP22 duplication. We identified 12 disease‐causing variants (from 13 families) in GARS1, AARS1, HARS1, WARS1, and YARS1 genes. Seven variants were determined to be novel. The frequency of overall ARS gene mutations was 1.22% among all independent patients diagnosed with CMT and 1.83% in patients negative for PMP22 duplication. WARS1 mutations have been reported to cause dHMN; however, in our patients with WARS1 variants, CMT was associated with sensory involvement. We analyzed genotype‐phenotype correlations and expanded the phenotypic spectrum of patients with CMT possessing ARS gene variants. We also characterized clinical phenotypes according to ARS genes. This study will be useful for performing exact molecular and clinical diagnoses and providing reference data for other population studies. [ABSTRACT FROM AUTHOR]

Using a ray matrix method, we analyze theoretically how the r and [theta] polarizations affect the resonator stability condition of two laser heads with or without thermal birefringence compensation. The resonator stability condition is analyzed graphically for a plane--parallel and a concave--concave resonator. The maximum range of stable region is found for both the short and the long cavity. The characteristics of the laser output power are confirmed experimentally in association with the resonator stability condition. The laser output power of 776 W is obtained with the optical-to-optical efficiency of 45% for a plane--parallel resonator with a short crystal separation.

A ray-tracing code has been developed, and the design parameters of the laser pump head were analyzed in terms of crystal diameter, doping concentration, and optical cavity diameter. According to the numerical analysis, we fabricated an efficient diode-pumped Nd:YAG laser and experimentally obtained 500-W output power. The output power is close to the numerically calculated output power of approximately 450 W and corresponds to an optical-to-optical conversion efficiency of 46.7% and an optical slope efficiency of 49%. OCIS codes: 140.3480, 140.5560.

We fabricated and analyzed the output power and polarization characteristics of an efficient diode-side-pumped Nd:YAG rod laser with a diffusive optical cavity. The resonator stability conditions are analyzed graphically in the symmetric and asymmetric configurations for a plane-parallel resonator. On the basis of an analysis of the stability condition and mode size for the r and [theta] polarizations, we clarify how the stable laser operation is possible for various resonator configurations. In particular, we show that the critical stability region of around [g.sub.1.sup.*] [g.sub.2.sup.*] = 0 provides a stable resonator in the symmetric resonator, even with a slight asymmetry. Experimentally, the output power and polarization characteristics are confirmed in association with the resonator stability condition. OCIS codes: 140.3410, 140.3480, 140.3530.