Online SOC Estimation of Battery for Wireless Tramcar

Wireless tramcars (battery‐driven tramcars) are developing to the actual application stage. The most important information to be considered while operating a wireless tramcar is the state of charge (SOC) of the battery. The purpose of this study is to develop an online method for SOC estimation. This method employs a new equivalent circuit of a lithium‐ion battery. SOC estimation using a conventional equivalent circuit results in a large error during fast current transients. In order to improve the accuracy of the estimation, we propose a new equivalent circuit of a lithium‐ion battery. Because the parameters of the proposed equivalent circuit depend on temperature, we propose a new method for SOC estimation in which the temperature estimation is taken into account. This method requires only instantaneous values of the voltage and current, and therefore no temperature measurement is required. Experimental results show that the accuracy of the proposed method is significantly improved when the temperature is taken into account. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(2): 83–89, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21174     

Investigation of Enantioselective Membrane Permeability of α-Lipoic Acid in Caco-2 and MDCKII Cell

α-Lipoic acid (LA) contains a chiral carbon and exists as two enantiomers (R-α-lipoic acid (RLA) and S-α-lipoic acid (SLA)). We previously demonstrated that oral bioavailability of RLA is better than that of SLA. This difference arose from the fraction absorbed multiplied by gastrointestinal availability (F_a × F_g) and hepatic availability (F_h) in the absorption phase. However, it remains unclear whether F_a and/or F_g are involved in enantioselectivity. In this study, Caco-2 cells and Madin–Darby canine kidney strain II cells were used to assess the enantioselectivity of membrane permeability. LA was actively transported from the apical side to basal side, regardless of the differences in its steric structure. Permeability rates were proportionally increased in the range of 10–250 µg LA/mL, and the permeability coefficient did not differ significantly between enantiomers. Hence, we conclude that enantioselective pharmacokinetics arose from the metabolism (F_h or F_g × F_h), and definitely not from the membrane permeation (F_a) in the absorption phase.     

Periodical Oscillation Phenomena Observed in Salt-Water Oscillator Experiments under Small Gravity Conditions

We examined periodical oscillation phenomena that were observed during salt-water oscillator experiments under a small gravity condition. This condition was realized by situating a lower-density gadolinium chloride (GdCl ₃) aqueous solution on a higher-density sodium chloride (NaCl) aqueous solution and applying a downward magnetic force. The GdCl ₃ solution concentration was 0.15 mol/kg (density ρ=1.03×10³ kg/m ³), and the NaCl concentration was varied to (A) 4.35 mol/kg (ρ=1.15×10³ kg/m ³), (B) 3.79 mol/kg (ρ=1.12×10³ kg/m ³), and (C) 2.49 mol/kg (ρ= 1.09×10 ³ kg/m ³). The magnitude of magnetic flux density was varied from 0 to 4.00 T. As the magnetic flux density grew larger, the GdCl ₃ solution was pulled downward by the magnetic force, and upward and downward flows were generated simultaneously at the orifice. These flows were accompanied by a periodical, locally thickened part. The thickened part was only observed when the magnetic force magnitude was small in cases (A) and (B). This flow pattern was not observed in case (C), in which a conventional salt-water oscillation was induced instead (C). In this paper we discuss new experimental results in which the oscillation cycles in cases (A) and (B) are strongly associated with the magnitude of the magnetic force and the density difference in the biphase solutions.     

Microbolometer Terahertz Focal Plane Array and Camera with Improved Sensitivity in the Sub-Terahertz Region

Journal of Infrared, Millimeter, and Terahertz Waves - A pixel in an uncooled microbolometer terahertz (THz) focal plane array (FPA) has a suspended structure above read-out integrated circuit...     

An induction heating diamond anvil cell for high pressure and temperature micro-Raman spectroscopic measurements

A new external heating configuration is presented for high-temperature diamond anvil cell instruments. The supporting rockers are thermally excited by induction from an externally mounted copper coil passing a 30 kHz alternating current. The inductive heating configuration therefore avoids the use of breakable wires, yet is capable of cell temperatures of 1100 K or higher. The diamond anvil cell has no resistive heaters, but uses a single-turn induction coil for elevating the temperature. The induction coil is placed near the diamonds and directly heats the tungsten carbide rockers that support the diamond. The temperature in the cell is determined from a temperature-power curve calibrated by the ratio between the intensities of the Stokes and anti-Stokes Raman lines of silicon. The high-pressure transformation of quartz to coesite is successfully observed by micro-Raman spectroscopy using this apparatus. The induction heating diamond anvil cell is thus a useful alternative to resistively heated diamond anvil cells.     

Chemi-emission of electrons from metal surfaces in the cutting process due to metal/gas interactions

The exo-electron emission behaviour from Ti, W, Mo, Fe, Al, Ni, Cd, Zn and Pb metals was investigated during and after being cut in O₂ and N₂ gases at a gas pressure of 3 × 10⁻² Pa and in a vacuum of 4 × 10⁻⁴ Pa. The results showed that the emission behaviour of electrons during and after cutting depends on the combination of metal and the surrounding gas species. The emission intensity of electrons while cutting various metals in O₂ gas increased sharply with an increase in the negative value of the heat cf formation, ΔH_f of the oxide. The emission intensity in N₂ was also higher at higher negative values of ΔH_f of the metal nitride. Electron emission intensity from the cut metal surface is concluded to be a function of the heat of formation of reaction products of the metal surface with the surrounding gas.     

Development of an advanced voltage control technique to improve voltage and reactive power characteristics of a large-scale power cable system

The power supply system for a metropolitan area consists of multiple 275-kV power cable systems to supply power to a large number of consumers. Each system has a large charging capacity (capacitive reactive power). When 275-kV power cable systems experience a voltage drop, their charging capacity decreases. However, the reactive power losses increase in the 275-kV overhead transmission lines, which supply large power to power cable systems, thus causing the performance of the power supply system to deteriorate. In this paper, the following three points are reported:

• 1 When the secondary power system of the trunk substation is a large-scale power cable system, new techniques can greatly improve the voltage and reactive power characteristics by controlling the rise of the sending-end voltage at the secondary side of the trunk substations and maintaining the voltage of power cable systems at a constant level.
• 2 In the use of this control technique, it has been demonstrated that controlling by the direct-detecting method of a voltage drop in the primary power system is superior to one that controls by the indirect-detecting method, which increases load power in the cable system.
• 3 The results of simulations obtained by using a 275-kV cable system model and a performance power system model show that the use of this control technique can produce a good effect despite the allowances made for the opposite effect, i.e., a decrease in the capacity of power capacitors resulting from voltage drop at the tertiary voltage of a 500-kV transformer.

This study is carried out to examine the possibility of lightning control using a photoionized plasma produced by a UV laser without an optical air breakdown. As the fundamental experiment, the characteristics of a laser-triggered spark gap (LTSG) are examined, where a laser beam is not irradiated on the surface of the electrodes. In this experiment, the KrF excimer laser is very effective in increasing the plasma density n_e and the reduction ratio p of 50 percent breakdown voltage against the self-breakdown voltage. The relation between n_e and p is increased by generating a long and high-density plasma parallel to the discharge axis. On the other hand, the abnormal discharge process in triggered lightning using a rocket is examined, and it is indicated that the most important condition to trigger a lightning discharge is the production of a plasma channel of length 200 m and density about 10¹⁹ m^?3. It is suggested that such a plasma channel could be produced by a KrF excimer laser with an energy of only about 3.67 J.     

Servo drive system and control characteristics of salient polepermanent magnet synchronous motor

Permanent magnet (PM) synchronous motors fed by PWM inverters are considered. PM motors sometimes have a saliency, in which the q-axis inductance is larger than the d-axis inductance. A high-performance servomotor drive system for a salient-pole PM motor is described. An armature current vector is actively controlled according to load conditions in order to use a reluctance torque effectively, and, as a result, a large torque can be produced. The control algorithm for the armature current vector is described, taking the demagnetization of the PM and the magnetic saturation into account. Characteristics such as torque, power factor, efficiency, power capability, transient responses, etc. are examined in detail by computer simulations and experimentally