Evaluation of grounding performance of energized substation by ground current measurement

Substation grounding systems typically build up a large network of various grounding electrodes, which consists of a substation grounding grid, multi-grounded transmission line skywires and distribution line neutral wires. Although the fall-of-potential (FOP) method has been widely used for ground resistance measurement, it is difficult to use the method in case of such a substation grounding system because of the difficulty of interpretation of the measured FOP profile. In this paper, we have presented a practical example of ground resistance measurement in a 154 kV substation under commercial operating condition. Conventional FOP tests and the measurement of ground current splits to each part of the grounding system were conducted simultaneously. A simple interpretation method of FOP profiles, with the measured ground current splits, has been suggested.     

Comparative Study of Visual and Instrumental Analyses of Shade Selection

The difference between visual and instrumental analyses of a shade selection on natural teeth was investigated. With visual analysis, five prosthodontist examined the middle third of the unrestored maxillary right central incisor of a patient using VITAPEN classical and Vita Toothguide 3D-MASTER tooth shade guide. In instrumental analysis, one prosthodontist examined the same teeth using a spectrophotometer (ShadepilotTM, Degudent, Hanau-Wolfgang, Germany, software 2.40). Overall, instrumental analysis is...     

Measurement development for cultural characteristics of mobile Internet users at the individual level

Culture plays an important role in how an information technology is developed and used. However, few studies attempt to identify the cultural traits most relevant to the specific technology being examined. The main purpose of this study is to develop measures for cultural characteristics of individual users with a specific information technology, the mobile Internet. We propose measures for four cultural characteristics important in the context of the mobile Internet, which are expected to be widely used in the future. The proposed measures were verified empirically through online surveys conducted in seven countries. The results indicate that the measures have high validity and reliability, as well as comparability among the seven countries. The paper ends with a discussion of the study’s limitations and implications.     

Thermal and dielectric properties of ZnO-B2O3-MO3glasses (M = W, Mo)

Glasses in the ZnO-B₂O₃-MO₃(M = W, Mo) ternary were examined as potential replacements to PbO-B₂O₃-SiO₂-ZnO glass frits with the low firing temperature (500–600^∘C) for the dielectric layer of a plasma display panels (PDPs). Glasses were melted in air at 950–1150^∘C in a narrow region of the ternary using standard reagent grade materials. The glasses were evaluated for glass transition temperature (T _g ), softening temperature (T _d ), the coefficient of thermal expansion (CTE), dielectric constant (ε _r ), and optical property. The glass transition temperature of the glasses varied between 470 and 560^∘C. The coefficient of thermal expansion and the dielectric constant of the glasses were in the range of 5–8 × 10^{− 6}/^∘C and 8–10, respectively. The addition of MO₃to ZnO-B₂O₃binary could induce the expansion of glass forming region, the reduction of T _g and the increase in the CTE and the dielectric constant of the glasses. Also, the effect of the addition of MO₃to ZnO-B₂O₃binary on the transmittance in the visible-light region (350–700 nm) was investigated.     

A 1.2 V 83 dB DR single‐ended input SC ΔΣ modulator including a large‐swing analog buffer for portable ECG applications

This study proposes a subsystem consisting of an analog buffer and a single‐ended input to a fully differential ΔΣ modulator to obtain low‐power consumption for portable electrocardiogram applications. With the proposed subsystem, the need for an inverting amplifier is avoided, and low‐power consumption is achieved. The ΔΣ modulator with a second order, 1 bit, and cascade of integrators feedforward structure consumes a low power, in which an inverting and a non‐inverting path implement a single‐ended input to fully‐differential signals. A double sampling technique is proposed for a digital‐to‐analog converter feedback circuit to reduce the effect of the reference voltage, reduce the amplifier requirements, and obtain low‐power consumption. Input‐bias and output‐bias transistors working in the weak‐inversion region are implemented to obtain an extremely large swing for the analog buffer. At a supply voltage of 1.2 V, signal bandwidth of 250 Hz, and sampling frequency of 128 kHz, the measurement results show that the modulator with a buffer achieves a 77 dB peak signal‐to‐noise‐distortion ratio, an effective‐number‐of‐bits of 12.5 bits, an 83 dB dynamic range, and a figure‐of‐merit of 156 dB. The total chip size is approximately 0.28 mm² with a standard 0.13 µm Complementary Metal‐Oxide‐Silicon (CMOS) process. Copyright © 2016 John Wiley & Sons, Ltd.     

Multifunctional Ru-AlN heating resistor films for high efficiency inkjet printhead

Ru-AlN thin films were suggested as a novel multifunctional heating resistor film for non-passivated type thermal inkjet printer devices. Ru-AlN thin films were prepared by plasma-enhanced atomic layer deposition in order to intermix Ru and AlN precisely. When the Ru intermixing ratios were optimized, Ru-AlN films showed a favorable electrical resistivity (from 490.9 to 75.3 μΩcm) and minimized temperature coefficient of resistance (TCR) values (from 335 to 360 ppm/K). Moreover, the Ru-AlN films showed a strong oxidation resistant as compared with commercially used TaN_0.8 films because the prepared Ru-AlN thin films had a typical nanocomposite structure. By applying electrical pulses to the heater device using Ru-AlN thin films for a Joule heating, a reliable operation was also proven.