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A simple and flexible method to realize a discharge-pumped C[O.sub.2] laser using a fast high-voltage solid-state switch is presented. A longitudinal excitation scheme that implements this simple configuration has been adapted. A fast high-voltage solid-state switch consisting of an avalanche transistor and commercially available series-connected IGBTs is coupled with a compact laser tube filled with C[O.sub.2] gas to provide the excitation energy. Laser oscillation has been demonstrated successfully and has produced several millijoules of output energy. DOI: 10.2961/jlmn.2019.02.0012 Keywords: gas laser, longitudinally excited gas laser, C[O.sub.2] laser, solid-state switch, IGBT

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In this paper we elaborate on recently developed molecular switch architectures and how these new systems can help with the realization of new functions and advancement of artificial molecular machines. Progress in chemically and photoinduced switches and motors is summarized and contextualized such that the reader may gain an appreciation for the novel tools that have come about in the past decade. Many of these systems offer distinct advantages over commonly employed switches, including improved fidelity, addressability, and robustness. Thus, this paper serves as a jumping-off point for researchers seeking new switching motifs for specific applications, or ones that address the limitations of presently available systems.

Optical signal processing (OSP) technology is a crucial part of the optical switching node in the modern optical-fiber communication system, especially when advanced modulation formats, e.g., quadrature amplitude modulation (QAM), are applied. However, the conventional on–off keying (OOK) signal is still widely used in access or metro transmission systems, which leads to the compatibility requirement of OSP for incoherent and coherent signals. In this paper, we propose a reservoir computing (RC)-OSP scheme based on nonlinear mapping behavior through a semiconductor optical amplifier (SOA) to deal with the non-return-to-zero (NRZ) signals and the differential quadrature phase-shift keying (DQPSK) signals in the nonlinear dense wavelength-division multiplexing (DWDM) channel. We optimized the key parameters of SOA-based RC to improve compensation performance. Based on the simulation investigation, we observed a significant improvement in signal quality over 10 dB compared to the distorted signals on each DWDM channel for both the NRZ and DQPSK transmission cases. The compatible OSP achieved by the proposed SOA-based RC could be a potential application of the optical switching node in the complex optical fiber communication system, where incoherent and coherent signals meet.

PurposeThere are only a small number of studies providing a comparison between SADI-S and Hess-Marceau’s BPD/Duodenal Switch (RY-DS) operations. We aimed to compare 5-year results of SADI-S 250 (common limb 250 cm) with RY-DS.Material and MethodsData of patients who underwent open SADI-S (n 226) and RY-DS (n 528) were retrospectively studied. EWL(%), EBMIL(%), TWL(%), antidiabetic effect, complications, and revision rate were compared between the two groups.ResultsAfter the first 12 months, EWL% (77.0% vs 73.3%) and TWL% (39.4% vs 38.9%) were statistically significantly better after SADI-S (p < 0.01, and p < 0.05 respectively), but not EBMIL% (p > 0.05). At nadir to 24–36 months, EWL, TBWL, and EBMIL after SADI-S was comparable to the RY-DS group. Up to the fourth and fifth year, better weight loss (TBWL, EBMIL, EWL) was observed after RY-DS than after SADI-S. Early complication rate was less (2.65%) in the SADI-S group vs 5.1% in the RY-DS. Protein deficiency and small bowel obstruction rates were also lower after SADI-S. 93.4% of patients achieved total remission of their diabetes. 7.5% of patients in the SADI-S group had symptoms of bile reflux, which was a main indication for revisions.ConclusionSADI-S has many advantages over RY-DS. However, weight loss and antidiabetic effects after the third year were marginally lower after SADI-S compared to RY-DS. SADI-S is less dangerous in terms of malabsorption and looks to be a reasonable alternative to RY-DS as a metabolic operation. RY-DS could be implemented for weight regain and/or bile reflux after SADI-S.

The paper presents the results of the development and experiments of a capacitor cell with stored energy up to 121.875 kJ with boosted switching-on, designed to operate at voltages up to 50 kV and a maximum discharge current amplitude of up to 500 kA. The cell has two circuits. The “fast” circuit, switched using a pseudo-spark switch, provides the initial boosted switching-on and increase in voltage in the load, and the main “slow” circuit, switched using trigger vacuum switches, ensures a subsequent increase in the current to the required value.

The article presents a new generation of ultra-fast hybrid switching systems (USH) for reliable, ultra-fast protection of various medium and low voltage DC systems (MVDC and LVDC). The DC switch-off takes place in a vacuum chamber (VC) cooperating with a semiconductor module using current commutation of natural or forced type. Against the background of the current state of science and technology, the paper depicts the basic scopes of USH applications and their particular suitability for operation in high magnetic energy DC circuits. In the case of DC system failures, this magnetic energy should be dissipated outside the system as soon as possible. Usually, magnetic blow-out switches (MBOS) with relatively low operating speed are used for this purpose. The article describes the theoretical basis and principles of construction of two types of novel USH systems: a direct current switching system (DCSS) and a direct current ultra-fast hybrid modular switch (DCU-HM). The DCSS family is designed for quench protection of superconducting electromagnets’ coils in all areas of application. The DCU-HM family is designed for the protection of all systems or vehicles of DC electrical traction and for related industrial applications. The conducted comparative analysis of the effectiveness of USH with respect to MBOS shows clear technical advantages of the new generation switching systems over MBOS. List of abbreviations used in the article is provided at the end.

Purpose The aims were to compare the 5-year outcomes of duodenal switch (DS) and single-anastomosis duodenal switch (SADI-S) in terms of weight loss; remission of comorbidities; nutritional status short- and long-term complications; postoperative mortality; and need for revisional surgery. Materials and Methods Multicenter prospective observational study of all consecutive patients undergoing DS or SADI-S in three high-volume hospitals. Results A total of 87 patients were included in the study, 43 submitted to DS and 44 to SADI-S, with similar basal characteristics, nutritional parameters, and BMI (52.9 kg/m 2 DS vs. 52.5 kg/m 2 SADI-S). Operative time was 152 min (± 32.6) in DS vs. 116 min (± 21.9) in SADI-S ( p  = 0.043). Short-term complications were similar for DS and SADI-S, both overall (11.8% vs. 11.6%), and ranged as Clavien-Dindo > II (4.5% vs. 4.7%), with no mortality. At 5 years, DS and SADI-S results were as follows: BMI 30.6 vs. 33.3 kg/m 2 ( p  = 0.023); %EWL 80.5% vs. 68.6% ( p  = 0.006); and %TWL 42.1 vs. 36.0 ( p  = 0.006). Comorbidity remission rates for DS and SADI-S were as follows: for diabetes, 92.8% vs. 85.7% (n.s.); for hypertension, 95.2% vs. 85.1% (n.s.); for sleep apnea, 75% vs. 73.3% (n.s.); and for dyslipidemia, 76.4% vs. 73.3% (n.s.). DS showed lower levels of vitamin B 12 , iron, vitamin E, and zinc than SADI-S ( p  =  < 0.005). In the long term, there were 4 surgical reinterventions (due to 1 internal hernia in the DS group and 1 internal hernia and 2 biliary refluxes in the SADI-S group) with no cases of persistent diarrhea or malnutrition. Conclusion Both DS and SADI-S allowed good weight control and resolution of comorbidities. DS achieved a greater weight loss compared to SADI-S, at the expense of longer operative time and lower vitamin and mineral levels. Graphical abstract

The miniaturization and low power consumption characteristics of RF MEMS (Radio Frequency Microelectromechanical System) switches provide new possibilities for the development of microsatellites and nanosatellites, which will play an increasingly important role in future space missions. This paper provides a comprehensive review of RF MEMS switches in satellite communication, detailing their working mechanisms, performance optimization strategies, and applications in reconfigurable antennas. It explores various driving mechanisms (electrostatic, piezoelectric, electromagnetic, thermoelectric) and contact mechanisms (capacitive, ohmic), highlighting their advantages, challenges, and advancements. The paper emphasizes strategies to enhance switch reliability and RF performance, including minimizing the impact of shocks, reducing driving voltage, improving contacts, and appropriate packaging. Finally, it discusses the enormous potential of RF MEMS switches in future satellite communications, addressing their technical advantages, challenges, and the necessity for further research to optimize design and manufacturing for broader applications and increased efficiency in space missions. The research findings of this review can serve as a reference for further design and improvement of RF MEMS switches, which are expected to play a more important role in future aerospace communication systems.