Model study on the formation of fuel NOx from cokes on combustion: Effect of metal oxides

To elucidate the process of ‘fuel NO_x’ formation from cokes and chars on combustion, carbons obtained from urea-resin and melamine-resin were subjected to combustion under a stream of pure oxygen at temperatures between 600 °C and 1000 °C. The carbons subjected to combustion without any additives produced a relatively small amount of NO_x, but, it was observed that the NO_x formation predominated at lower temperatures of combustion. When the combustion was carried out with the addition of metal oxides, such as iron oxides and cupric oxide, the amount of NO_x formed increased markedly but silicon dioxide had no such effect.     

New Members of the Pb-based 1222 Superconductor Containing Phosphorus: (Pb0.75P0.25)Sr2(Ln1.9?x Ce x Sr0.1)Cu2O z (Ln=Sm and Gd)

We previously reported on the synthesis of new Pb-based 1222 superconductor containing phosphorus in the (Pb_0.75P_0.25)Sr₂(Eu_1.9−x Ce _x Sr_0.1)Cu₂O _z system. Recently, we have discovered new members of the Pb-based 1222 superconductor containing phosphorus in the (Pb_0.75P_0.25)Sr₂(Ln_1.9−x Ce _x Sr_0.1)Cu₂O _z (Ln=Sm and Gd) systems. In each system, it is found that the samples of almost the single 1222 phase can be obtained for a wide composition area of 0.3≤x≤1.0. After annealing under 143 atm O₂ atmosphere at 400 °C, each sample of Ln=Sm and Gd with x=0.3 is found to show an onset of resistivity-drop at about 28 K and at about 24 K, respectively. Moreover, each samples of Ln=Sm and Gd is found to show an onset of diamagnetic signal at about 25 K and about 22 K, respectively. From these facts, these samples of Ln=Sm and Gd are found to be new members of the Pb-based 1222 superconductor containing phosphorus.     

Proposal of Bow-Tie Antenna-Integrated Resonant Tunneling Diode Transmitter Utilizing Relaxation Oscillations and Its Application to Short-Distance Wireless Communications

We propose a resonant tunneling diode (RTD)-based relaxation oscillator and an oscillator-based terahertz (THz) wireless link that compensate for shortfalls in RF-oscillator emission power by adding several relaxation carrier wave harmonic modes. We believe that the proposed link can perform as well as or superior to large component-based wireless links that suppress power dissipation using collimating lenses and/or discrete antennas to add the power output of a relaxation oscillator. This hypothesis is investigated analytically using a physics-based equivalent circuit model of the proposed oscillator and a link budget analysis of the relaxation carrier wave. The model, which incorporates effects such as the non-linearity of the tunneling diode and the electromagnetic properties of the integrated bow-tie antenna on the oscillator, is used to quantitatively investigate the link characteristics in terms of the signal-to-noise ratio (SNR) and other parameters and to demonstrate that, by applying an appropriate device size and number of harmonic modes in the occupied bandwidth, link performance comparable to that of previously reported wireless links can be achieved. Based on these results, we discuss the potential for practical implementation of the proposed link configuration in mobile link applications for use in environments such as the Internet of Things (IoT).     

Electronic structure of the ladder-chain compound Sr14−xCaxCu24O41

The electronic structure of the ladder-chain compound Sr_14−xCa_xCu₂₄O₄₁ is studied by ab initio calculations within the local density approximation. The effects of Ca substitution and structure modulation on electronic structure are discussed. It is found that 0.05 holes per copper atom are on the ladder layers for fully substituted compound, Ca₁₄Cu₂₄O₄₁.     

Mixing qualitative and quantitative research in developmental science: Uses and methodological choices.

Multiple methods are vital to understanding development as a dynamic, transactional process. This article focuses on the ways in which quantitative and qualitative methodologies can be combined to enrich developmental science and the study of human development, focusing on the practical questions of "when" and "how." Research situations that may be especially suited to mixing qualitative and quantitative approaches are described. The authors also discuss potential choices for using mixed quantitative- qualitative approaches in study design, sampling, construction of measures or interview protocols, collaborations, and data analysis relevant to developmental science. Finally, they discuss some common pitfalls that occur in mixing these methods and include suggestions for surmounting them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Carrier separation analysis for clarifying carrier conduction and degradation mechanisms in high-k stack gate dielectrics

The carrier conduction and the degradation mechanism in n⁺gate p-channel metal-insulator-semiconductor field-effect-transistors with HfAlO_X (Hf: 60 at.%, Al: 40 at.%)/SiO₂ dielectric layers have been investigated using carrier separation method. Since gate current depends on substrate bias and both electron and hole currents are independent of temperature over the range of 25–150 °C, the conduction mechanism for both currents is controlled by a tunneling process. As the interfacial SiO₂ layer (IL) thickness increases in a fixed high-k layer thickness (T_high-k), a dominant carrier in the leakage current changes from hole to electron around 2.2-nm-thick IL. This is due to an asymmetric barrier height for electrons and holes at the SiO₂/Si interface. On the contrary, in the case of a fixed IL thickness of 1.3 nm, the hole current is dominant in the leakage current, regardless of T_high-k. It is shown that the dominant carrier in the leakage current depends on the structure of the high-k stack. Both electron and hole currents for the stress-induced-leakage-current (SILC) state increase slightly relative to the initial currents, which means that the trap generation in the high-k stack occurs near both the conduction band edge of n⁺poly-Si gate and the valence band edge of Si substrate. The electron current at soft breakdown (SBD) state dramatically increases over that for the SILC state, while the hole currents for both the SILC state and SBD are almost the same. This indicates that the defect sites generated in the high-k stack after SBD are located at energies near the conduction band edge of n⁺poly-Si gate. Both the defect generation rate and the defect size in the HfAlO_X/SiO₂ stacks are large compared with those in SiO₂. It is inferred that, in high-k dielectric stack, the defect generation mainly occurs in the high-k side rather than the IL side, and the defect size larger than the case of SiO₂ could be related to a larger dielectric constant of the high-k layer.     

Determination of mercury in fish by cold vapour atomic absorption spectrometry using an automatic mercury analyzer

The concentration of mercury in fish samples from the Atlantic coast of Ghana was determined using a simple, rapid and accurate method. A mixture of HNO₃, HClO₄ and H₂SO₄ was used for complete oxidation of organic tissue. Mercury is detected by the cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer developed at the National Institute for Minamata Disease (NIMD). In total, 56 samples covering 13 species of fish were analysed for total mercury. The concentration of mercury in the edible muscle tissue of these fish ranged from 0.004 to 0.122 μg g⁻¹ wet weight. All fish species sampled had concentrations less than the WHO limit of 0.5 μg g⁻¹ wet weight. The low concentrations of mercury detected in the samples do not constitute any significant mercury exposure to the general population through fish consumption.     

Modeling and deforming a virtual dense elastic object with the haptic device PHANToM

In recent years, there have been various problems in medical treatments, of which human error by the surgeon in an operation is one of the most serious. In order to minimize human error in an operation, we need a medical training system by which inexperienced surgeons can try operating again and again to improve their skill. In this research, we construct a system of modeling a virtual dense elastic object, and deforming that object using a haptic device called PHANToM. In the system which we construct, we use two PCs to distribute the process of calculation, and SCRAMNet+ is used to connect each PC. PHANToM is used to operate on the object and to express the force which is generated from the deformation of the object. We represent the dense object by using voxels and tetrahedrons, and the elastic object by using a spring-mass model. A virtual dense elastic object is obtained by computed tomography (CT) or magnetic resonance imaging (MRI) to express the patient’s organs.