Larval Feeding Stimulants for a Rutaceae-Feeding Swallowtail Butterfly, Papilio xuthus L. in Citrus unshiu Leaves

Larvae of a swallowtail butterfly, Papilio xuthus L., feed exclusively on plants of the family Rutaceae, including various Citrus crops. Larvae were strongly stimulated to feed on paper strips impregnated with ethanolic extracts of host-plant leaves. Stimulation of feeding on extracts of Citrus unshiu leaves required a mixture of chemicals including sugars (d-glucose, d-fructose, and d-sucrose), a betaine [(−)-stachydrine], a cyclic peptide (citrusin I), a polymethoxyflavone (isosinensetin), and the lipids 1-linolenoylglycerol, 1-linoleoylglycerol, 1-octadecenoylglycerol, 1-stearoylglycerol, and 1,2-dilinolenoyl-3-galactosyl-sn-glycerol. When these compounds were assayed individually, few larvae consumed test strips. However, larvae readily chewed the test strips treated with a mixture of all compounds, indicating that host recognition by P. xuthus larvae is mediated by a specific combination of both primary and secondary substances. Comparison of 11 stimulant components with 10 compounds from C. unshiu leaves previously reported as stimulant components for oviposition by P. xuthus adult females revealed only one compound, stachydrine, as an ingredient in common. While the larval feeding-stimulant mixture is dominated by nutrients and other compounds of general significance for primary metabolism, the component oviposition stimulants are mostly secondary substances, including flavonoid glycosides, protoalkaloids, a cyclitol, and a betaine, that have restricted distributions in plants. Reliance by adult females on unique profiles of secondary compounds presumably reflects the need to locate and recognize specific host-plant species within a diverse flora. Since the initial host choice for the larvae is made typically by the ovipositing female, however, unique secondary compounds may be less important for larval feeding than are compounds useful for indicating food and microhabitat quality once on the host plant.     

Application of flamelet model to large‐eddy simulation of turbulent reacting liquid flows

Large‐eddy simulations using the flamelet models are applied to turbulent reacting liquid flows and validated by comparing with the experiments. The computations are performed for two reaction conditions, namely a rapid reaction and a moderately fast reaction in a grid‐generated turbulent flow. For the flamelet models, both the steady flamelet model and the unsteady Lagrangian flamelet model are tested. A second‐order, irreversible, and isothermal reaction is considered. The results show that the flamelet models inherently developed for turbulent combustion are applicable to turbulent reacting liquid flows, provided that the model coefficient in evaluating the subgrid scale variance of mixture fraction in the scale‐similarity model is set to be 5.0. The rapid reaction can be adequately predicted by both the steady and unsteady Lagrangian flamelet models, whereas the moderately fast reaction can be predicted only by the unsteady Lagrangian flamelet model which is capable to take slow chemical processes into account. © 2010 American Institute of Chemical Engineers AIChE J,, 2011     

Study of Superconductor Recovery Time Characteristics and High‐Speed Reclosing of Electromagnetic Repulsion Switch

Using a high‐temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor and a vacuum interrupter serving as the commutation switch were connected in parallel using a bypass coil. When the fault current flows in this equipment, the superconductor is quenched and the current is then transferred to the parallel coil due to the voltage drop in the superconductor. This large current in the parallel coil actuates the magnetic repulsion mechanism of the vacuum interrupter and the current in the superconductor is interrupted. Using this equipment, the current flow time in the superconductor can easily be minimized. On the other hand, the fault current is also easily limited by the large reactance of the parallel coil. This system has many advantages. Thus, we introduced an electromagnetic repulsion switch. High‐speed reclosing after interrupting the fault current in the electrical power system is essential. Thus, the SFCL should recover to the superconducting state before high‐speed reclosing. But the superconductor generates heat at the time of quenching, and it takes time to recover to the superconducting state. Therefore, the recovery time is an issue. In this paper, we study the superconductor recovery time. We also propose an electromagnetic repulsion switch with a reclosing system. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(3): 12–19, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21072     

Study of DC circuit breaker of H2‐N2 gas mixture for high voltage

Global warming caused by such gases as CO₂ is a subject of great concern. Automobile emissions are an especially great problem in this respect. Therefore, hybrid cars are being widely developed and used. Because hybrid cars use electric power and gasoline, their emissions of CO₂ are reduced. The electric motor of a hybrid car is driven by a battery, which has large capacity. Therefore, relays must interrupt a high DC current on switching between the electric motor and the gasoline engine, and hydrogen gas‐filled relays are used for the purpose. In interruption tests in which we investigated the basic characteristics of hydrogen gas, the DC current did not reach a current‐zero point. Thus, the current must be coerced to zero by using a high arc voltage. The loss coefficient and arc voltages of hydrogen are high, and we therefore performed interruption tests using a high arc voltage. Interruption tests and dielectric breakdowns test of air, pure hydrogen, and a hydrogen‐nitrogen mixture indicated that an 80%–20% H₂–N₂ mixture is the most effective. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(2): 9–17, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21042     

A Study of Hydrogen Generation with Doubly‐Fed Adjustable Speed Wind Generator

This paper presents a combination system for wind power generation and hydrogen generation. In the proposed system, a doubly‐fed synchronous generator (DFSG) is used as an adjustable speed wind generator, and an electrolyzer is connected to its terminals for hydrogen generation, which is controlled by power electronic converters. The output power from the wind generator is smoothed and supplied to the power system as well as to the electrolyzer to generate hydrogen under cooperative control between the wind generator and the electrolyzer. The performance of the proposed system is investigated by simulation analyses, in which simulations are performed using PSCAD/EMTDC. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(3): 27–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21003     

Analysis of the Clean Development Mechanism Considering the Environmental Co-benefits of Reducing Air Pollutants in China

An electricity generation planning model of the six major Chinese power grids was developed based on the General Algebraic Modeling System to evaluate and analyze the CDM （clean development mechanism）, including consideration of the environmental co-benefits of reductions in air pollutants （SO~, NO~ and particulate matter） achieved by advanced electricity generation technologies incorporating CCS （carbon capture and storage）. An objective function was developed that included revenue from sales of electric power, total system cost, the cost of CO2 transport and storage, and emissions reduction co-benefits for SOx, NO~, and particulate matter. The objective function was minimized using an optimization model. We also developed a method for evaluating and analyzing the potential for transferring advanced power generation technologies into the Chinese power system through the CDM. We found that： （1） thermal power generation is predominant in the Chinese electricity system and will remain so for a long time; （2） advanced thermal plants are being installed as a result of the CDM, which contribute to decreasing emissions of CO2 and other air pollutants; and （3） CCS projects have significant potential to reduce substantial and sustained CO2 emissions from the Chinese power and industrial sectors.     

Controllable threshold voltage of a pentacene field-effect transistor based on a double-dielectric structure

The authors report controllable threshold voltage (V_th) in a pentacene field-effect transistor based on a double-dielectric structure of poly(perfluoroalkenyl vinyl ether) (CYTOP) and SiO₂. When a positive switching voltage is applied to the gate electrode of the transistor, electrons traverse through the pentacene and CYTOP layers and subsequently trapped at the CYTOP/SiO₂ interface. The trapped electrons induce accumulation of additional holes in the pentacene conducting channel, resulting in a large V_th shift from ?4.4 to +4.6 V. By applying a negative switching voltage, the trapped electrons are removed from the CYTOP/SiO₂ interface, resulting in V_th returning to an initial value. The V_th shift caused by this floating gate-like effect is reversible and very time-stable allowing the transistor to be applicable to a nonvolatile memory that has excellent retention stability of stored data.     

Long‐period observation of neutral current at an extra‐high‐voltage transformer in Chubu region

We have observed and recorded the neutral current of a 500‐kV transformer at a substation in the Chubu region since 2008 in order to detect electromagnetic anomalies associated with earthquakes. In this study, we could not ?nd any particular anomalous change of the neutral current before and after earthquakes (e.g., for the Suruga Bay Earthquake of August 11, 2009). However, from the results of a quantitative analysis between geomagnetic ?eld data and neutral current data, we would be able to investigate the underground electric conductivities near the substations. It would be possible to monitor changes of subsurface electromagnetic structure before and after earthquakes. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 32–38, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22297     

Effects of Synchronous Machine Saturation,Circuit Parameters,and Control Systems on Transient Stability

The effects of synchronous machine iron saturation, circuit parameters, and control systems on the power system transient stability phenomena are presented in this paper. Effect of saturation is considered to be very important on the power system steady-state and transient performances when it is required to calculate the power system stability characteristics accurately. For solid round rotor body synchronous machines, saturation effects are significant in both d- and q-axis, and because of this nonlinearity, the d- and q-axis magnetizing reactances are depressed to a considerable degree from their unsaturated values under both steady-state and transient operations. The system stability performance is also greatly influenced by the machine control system and damper circuit parameter variations.     

Preparation and evaluation of sub-100 nm Pb(Zr,Ti)O3 films derived from modified sol-gel solutions for low-voltage operation of feram

Abstract

Sub-100 nm PbZr_0.3Ti_0.7O₃ (PZT) films were prepared on Pt/SiO₂/Si substrates from modified sol-gel solutions without using any seeding layers. Firstly, we studied Pb content [Pb/(Zr+Ti)] dependence of 90-nm-thick films. In the wide Pb content region of 108 – 125%, the films had perovskite-single-phase fine columnar grains with (111)-orientation and no voids. Electric properties were dependent on Pb content. The film with good microstructure, rectangular hysteresis, high remanent polarization (P_r), and low leakage current was gained for Pb content of 116%. Secondly, we studied film thickness dependence of PZT(116/30/70) films. Films from 90 down to 61 nm in thickness were prepared. We found that the sub-100 nm films with good microstructures could be prepared from the modified solutions. The sub-100 nm films had saturation voltage of 1.25 V and high P_r even at 1 V or less. In particular, a 61-nm-thick film had high.P_r of 17 μC/cm2 at 0.75 V.