Single-Phase 13-Level Power Conditioning System for Peak Power Reduction of a High-Speed Railway Substation

The control and operation of a single-phase 13-level power conditioning system (PCS) for peak power reduction of a high-speed railway substation (HSRS) are proposed. This PCS is a single-phase 3100 V, 2 MVA 13-level H-bridge multi-level inverter structure. It has excellent power quality. It is easy to serialize by voltage. In addition, the DC bus power of each cell inverter is supplied by lithium-ion batteries. The generalized reduction gradient optimization algorithm based on past load pattern is applied to the power management system for peak power reduction of HSRS. The phase detector and power controller for the control of a single-phase PCS based on virtually coordinated axes using an all-pass filter are expected to be robust to external disturbances with fast response characteristics. This study also proposes an adapted select switch (ASS) method that can change the switching depending on the operation state of PCS and the state of charge (SOC) of the battery to minimize battery imbalance by controlling each cell inverter of the H-bridge. The validity of the proposed system was confirmed by PSiM simulation and experiments using a demonstration system of 6 MW PCS and 2.68 MWh batteries at one of Gyeongbu high-speed line substations in Korea. Document type: Articl

Customer-Supplier Relationships and the Cost of Debt

We examine the relation between the existence of a large customer and the cost of debt financing. We find that credit ratings are lower for firms with a large customer. We also find that yield spreads are higher for firms with a large customer. The results indicate that firms having a large customer have higher cost of debt financing, which is consistent with our capital structure hypothesis

Mandatory IFRS Adoption And Financial Analysts' Information Environment: Evidence From Korean Market

The paper examines the effects of the mandatory adoption of International Financial Reporting Standards (IFRS) on financial analysts’ information environment, specifically on analysts forecast accuracy in the Korean market. We find that financial analysts’ forecast accuracy improves after the mandatory IFRS adoption. We further investigate the source of observed accuracy enhancements and find that the improved forecast accuracy is attributable to the increased precision in analysts’ information sets for KOSPI firms and increased opportunity for earnings management for KOSDAQ firms. We also find that the analyst coverage in Korean market is reduced after mandatory IFRS adoption

Deciphering The Seemingly Counter Intuitive Impact Of Firm Innovation On Stock Returns In The Electronics Sector

This paper investigates the impact of firms’ innovative activities on stock returns for firms in the electronics sector. The regression analysis provided counter intuitive result that exploitation and exploration are not significant in explaining stock returns. However, further analysis on firm size revealed that innovation have statistically significant explanatory power in the stock returns of relatively large firms, and the effect was negative and positive for exploitation and exploration, respectively. This is consistent with general expectations. The result implies that equity investors may believe that innovation is important for relatively larger firms only

Compact Silicon Slot Waveguide Intersection Based on Mode Transformation and Multimode Interference

Silicon slot waveguide intersections are necessary for photonic-integrated circuits based on silicon slot waveguides. We theoretically investigate a compact silicon slot waveguide intersection, which consists of mode transformers and a multimode strip waveguide crossing. The mode transformer before the crossing converts the slot waveguide mode into strip waveguide modes with amplitudes and phases appropriate for efficient operation of the crossing, which is based on multimode interference. The reverse conversion happens in the mode transformer after the crossing. The investigated intersection has a throughput of -0.078 dB, a crosstalk of -41 dB, and a footprint of 79.2 mu m(2). Its properties are better than those of previous silicon slot waveguide intersections, and especially its footprint is less than 33% of the previous ones. The intersection may be used for matrix switches based on silicon slot waveguides

Bacterial community analysis of sediment seep in Kagoshima Bay, Japan

1902-1906Microorganisms in the deep-sea environments such as hydrothermal vent and cold-seep regions are primary energy producers and an important community in these ecosystems. We have used 454-Pyrosequencing and 16S rDNA clone library methods to determine the diversity of bacteria in the sediment of the seep regions around the vestimentiferan tubeworm habitat at Kagoshima Bay. Taxonomic composition from both libraries suggested that 454-Pyrosequencing methods can represent more diverse groups than the conventional clone library methods. Most abundant taxa with higher folds were Proteobacteria and Bacteroidetes found in both methods. Through the 454-Pyrosequencing method, we were able to detect underrepresented taxa as well as non-detectable taxa. This analyses and comparison provide bacterial taxonomic group detection efficiency of both library types and emphasize the different uses and utilities for exploring the unknown microbial domain

Meteorin regulates mesendoderm development by enhancing nodal expression

During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development. It is highly expressed in the inner cell mass of blastocysts and further in the epiblast and extra-embryonic ectoderm during gastrulation. Genetic ablation of the Meteorin gene resulted in early embryonic lethality, presumably due to impaired lineage allocation and subsequent cell accumulation. Embryoid body culture using Meteorin-null embryonic stem (ES) cells showed reduced Nodal expression and concomitant impairment of mesendoderm specification. Meteorin-null embryos displayed reduced levels of Nodal transcripts before the gastrulation stage, and impaired expression of Goosecoid, a definitive endoderm marker, during gastrulation, while the proximo-distal and anterior-posterior axes and primitive streak formation were preserved. Our results show that Meteorin is a novel regulator of Nodal transcription and is required to maintain sufficient Nodal levels for endoderm formation, thereby providing new insights in the regulation of mesendoderm allocation.open1113sciescopu

Effect of biochars pyrolyzed in N2 and CO2, and feedstock on microbial community in metal(loid)s contaminated soils

Little is known about the effects of applying amendments on soil for immobilizing metal(loid)s on the soil microbial community. Alterations in the microbial community were examined after incubation of treated contaminated soils. One soil was contaminated with Pb and As, a second soil with Cd and Zn. Red pepper stalk (RPS) and biochars produced from RPS in either N2 atmosphere (RPSN) or CO2 atmosphere (RPSC) were applied at a rate of 2.5% to the two soils and incubated for 30 days. Bacterial communities of control and treated soils were characterized by sequencing 16S rRNA genes using the Illumina MiSeq sequencing. In both soils, bacterial richness increased in the amended soils, though somewhat differently between the treatments. Evenness values decreased significantly, and the final overall diversities were reduced. The neutralization of pH, reduced available concentrations of Pb or Cd, and supplementation of available carbon and surface area could be possible factors affecting the community changes. Biochar amendments caused the soil bacterial communities to become more similar than those in the not amended soils. The bacterial community structures at the phylum and genus levels showed that amendment addition might restore the normal bacterial community of soils, and cause soil bacterial communities in contaminated soils to normalize and stabilize

Validity of gait parameters for hip flexor contracture in patients with cerebral palsy

Background: Psoas contracture is known to cause abnormal hip motion in patients with cerebral palsy. The authors investigated the clinical relevance of hip kinematic and kinetic parameters, and 3D modeled psoas length in terms of discriminant validty, convergent validity, and responsiveness. Methods: Twenty-four patients with cerebral palsy (mean age 6.9 years) and 28 normal children (mean age 7.6 years) were included. Kinematic and kinetic data were obtained by three dimensional gait analysis, and psoas lengths were determined using a musculoskeletal modeling technique. Validity of the hip parameters were evaluated. Results: In discriminant validity, maximum psoas length (effect size r = 0.740), maximum pelvic tilt (0.710), maximum hip flexion in late swing (0.728), maximum hip extension in stance (0.743), and hip flexor index (0.792) showed favorable discriminant ability between the normal controls and the patients. In convergent validity, maximum psoas length was not significantly correlated with maximum hip extension in stance in control group whereas it was correlated with maximum hip extension in stance (r = -0.933, p < 0.001) in the patients group. In responsiveness, maximum pelvic tilt (p = 0.008), maximum hip extension in stance (p = 0.001), maximum psoas length (p < 0.001), and hip flexor index (p < 0.001) showed significant improvement post-operatively. Conclusions: Maximum pelvic tilt, maximum psoas length, hip flexor index, and maximum hip extension in stance were found to be clinically relevant parameters in evaluating hip flexor contracture.Y

A Case of Inadvertent Anterior Chamber and Corneal Stromal Injection with Antibiotics during Cataract Operation

Purpose: To report a case of inadvertent anterior chamber and cornea stromal injection with high dose antibiotics and steroids during cataract operation. Methods: During cataract operation on a 78 year-old female patient, high dose gentamicin (20 mg/0.5 ml) and dexamethasone (2 mg/0.5 ml) were inadvertently injected into the anterior chamber and cornea stroma when making cornea edema for sealing of the incision sites. Anterior chamber irrigation with balanced salt solution (BSS) was immediately administered. On postoperative day one, extensive cornea edema was noted, and best-corrected visual acuity was 0.2. Descemet's membrane folds were observed around the corneal incision sites. Topical 5% NaCl and 1% prednisolone were started. Results: Four weeks postoperatively, corneal edema began to reduce significantly. At four months postoperatively, corneal edema fully resolved, and best-corrected visual acuity was 0.8. However, some Descemet's membrane folds still remained, and a decrease in the number of endothelial cells was noted by specular microscope. Conclusions: In this case involving anterior chamber and cornea stromal injection with high dose antibiotics and steroids, immediate anterior chamber irrigation with balanced salt solution seemed an appropriate management, and the patient's long-term visual acuity appears good. To prevent such mistakes, precise labeling of all solutions and use of different syringe needles should be considered.ope