Dielectric aging of Mn and V-codoped BaTiO3 was investigated. The increase of V concentration had little influence on aging, whereas that of Mn increased it. Thermally stimulated depolarization current (TSDC) of low Mn concentration specimen showed one peak, whereas Mn-increased specimen showed two peaks. The first and second peak is supposed to be caused by the phase transition of the undoped core region and the defect dipole of Mn such as MnTi″-VO•• or MnTi′-VO••, respectively. High TSDC associated with the defect dipole of Mn and significant aging rate experimentally demonstrates that the dielectric aging is controlled by the defect dipole.

Study DesignThis is a retrospective study that was done according to clinical and radiological evaluation.PurposeWe analyzed the clinical and radiological outcomes of minimally invasive transforaminal lumbar interbody single level fusion.Overview of LiteratureMinimally invasive transforaminal lumbar interbody fusion is effective surgical method for treating degenerative lumbar disease.MethodsThe study was conducted on 56 patients who were available for longer than 2 years (range, 24 to 45 months) follow-up after undergoing minimally invasive transforminal lumbar interbody single level fusion. Clinical evaluation was performed by the analysis of the visual analogue scale (VAS) score and the Oswestry Disability Index (ODI) and the Kirkaldy-Willis score. For the radiological evaluation, the disc space height, the segmental lumbar lordotic angle and the whole lumbar lordotic angle were analyzed. At the final follow-up after operation, the fusion rate was analyzed according to Bridwell's anterior fusion grade.ResultsFor the evaluation of clinical outcomes, the VAS score was reduced from an average of 6.7 prior to surgery to an average of 1.8 at the final follow-up. The ODI was decreased from an average of 36.5 prior to surgery to an average of 12.8 at the final follow-up. In regard to the clinical outcomes evaluated by the Kirkaldy-Willis score, better than good results were obtained in 52 cases (92.9%). For the radiological evaluation, the disc space height (p = 0.002), and the whole lumbar lordotic angle (p = 0.001) were increased at the final follow-up. At the final follow-up, regarding the interbody fusion, radiological union was obtained in 54 cases (95.4%).ConclusionsWe think that if surgeons become familiar with the surgical techniques, this is a useful method for minimally invasive spinal surgery.

Abstract:The microgrid and demand response (DR) are important technologies for future power grids. Among the variety of microgrid operations, the multi-agent system (MAS) has attracted considerable attention. In a microgrid with MAS, the agents installed on the microgrid components operate optimally by communicating with each other. This paper proposes an operation algorithm for the individual agents of a test microgrid that consists of a battery energy storage system (BESS) and an intelligent load. A microgrid central controller to manage the microgrid can exchange information with each agent. The BESS agent performs scheduling for maximum benefit in response to the electricity price and BESS state of charge (SOC) through a fuzzy system. The intelligent load agent assumes that the industrial load performs scheduling for maximum benefit by calculating the hourly production cost. The agent operation algorithm includes a scheduling algorithm using day-ahead pricing in the DR program and a real-time operation algorithm for emergency situations using emergency demand response (EDR). The proposed algorithm and operation strategy were implemented both by a hardware-in-the-loop simulation test using OPAL-RT and an actual hardware test by connecting a new distribution simulator.

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I (Current)-V (voltage) characteristics of Mn-doped BaTiO3 multilayer ceramic capacitor were investigated. The increase of Mn concentration reduced the slope of current increase with increasing dc field and enhanced the dc field to the abrupt increase of current and thereby breakdown. Ohmic, Schottky, and Poole-Frenkel type conduction was successively observed with the increase of dc field in all specimens. The region of Child's law did not appear before breakdown, which suggests space charge limited (SCL) conduction with field enhanced trap barrier lowering. A peak of thermally stimulated depolarization current (TSDC) beyond 300 °C associated with trapped space charges appeared, which increased by the increase of Mn concentration. In addition, the peak intensity increased to a maximum value and then decreased again with increasing polarization dc field in TSDC measurement. Its activation energies were around 1.9 eV for all specimens, which is very close to the energy level for the ionization of Mn3+/Mn2+. These results experimentally demonstrate the role of the variable valence acceptor Mn as trapping center for injected charges, and the occurrence of field enhanced trap charge release, and therefore, the conduction mechanism can be described by the SCL model incorporating the Poole-Frenkel effect.