Zero-dimensional chemical kinetic simulation of ROS/RNSin pulsed pulsed-discharge exposed water

The concentration variations of reactive oxygen/nitrogen species in water, such as H2O2, NO2 −, and NO3 − generated by pulsed-discharge plasma exposure, are calculated using reaction rates of chemical reactions and acid-base equilibrium in water. The calculated concentrations and pH values are in good agreement with measured data within the range where the significant changes of the measured data are observed. The rate constant for ONOOH generation is estimated to be 7.8 × 103 M−2 s−1, and this value is in good agreement with previously reported values. The generation rates of H2O2, NO2 −, and NO3 − are estimated to be 7.70 × 10−7, 4.10 × 10−7, and 1.10 × 10−7 M s−1, respectively

Evaluation of Mechanical Torque Acting on Scatterer in Microwave Vortex Fields

This letter discusses the generation of vortex fields in microwave frequency range using a corrugated waveguide and a dielectric plate which has a spiral structure. Quantitative investigation of the microwave vortex field is carried out by numerical simulations of the finite-difference time domain (FDTD) method. In addition, the mechanical torque acting on a scatterer in the microwave vortex field is evaluated aiming to use the application for remote manipulation of macroscopic objects

Orbital angular momentum of Liénard–Wiechert fields

We derive a general expression for the electromagnetic field radiated by a relativistic charged particle with arbitrary periodic orbit, in the form of multi-pole expansion of the Liénard–Wiechert potential, which explicitly includes the charged particle motion. Using this expression, we discuss the orbital angular momentum radiated from a relativistic charged particle. It has recently been indicated that the radiation emitted by circularly orbiting charged particles carries well-defined orbital angular momentum. We show that, even for the general cases of arbitrary periodic orbits, the radiation field possesses well-defined orbital angular momentum

Stable time-domain boundary integral equation method foraxisymmetric coupled charge-electromagnetic field problems

In this paper, a stable time-domain boundary integral equation method for transient electromagnetic wave is presented. Careful numerical treatments of the integral equation for stable solution are especially stated. The formulation is given for axisymmetric electromagnetic field problems. A numerical simulation of particle accelerator wake field is also given as an example

Statistical Analysis of the Kuzuryu River Water Quality

The water quality data of the Kuzuryu River at 11 stations from April 1976 t.o March 1986 were analyzed by correlation analysis method and principal component analysis method. The results were as follows. 1. The negative correlation between water temperature and DO and the positive one between BOD and COD were found. 2. From the principal component analysis based on the correlation matrix of the 7 items (water temperature，pH、DO，BOD、COD、SS and Coliform)，the first component (Zl) was identified as the organic water pollution factor. 3. The 4 items (DO、BOD，COD and Coliform) which showed high contribution to the first component were selected for the further analysis. The equation derived from the first component of the principal component analysis with 4 items was used to evaluate Water Quality Index (WQI). WQI displayed less variation than BOD and it could be a more excellent index than common water pollution indicators. 4. By using each principal component and factor loading，11 stations were classified into three groups according to their water qualities

Conceptual Design of 3-D FDTD Dedicated Computer With Dataflow Architecture for High Performance Microwave Simulation

For practical use of microwave simulations in industry applications such as high frequency product design, this paper presents a conceptual design of 3-D finite difference time domain (FDTD) dedicated computer with dataflow architecture as one of the portable high performance computing technologies. A basic concept of the dataflow architecture for the FDTD dedicated computer itself was presented already in 2003 for 2-D microwave simulations. Detail design of 3-D FDTD dataflow machine is considered in this paper

Design study of ultrahigh-speed microwave simulator engine

A design study of microwave simulator engine is presented in this paper. Taking note the simplicity and duality of data flow in finite-difference time-domain (FDTD) scheme, conceptual and hardware designs of the engine are shown for two-dimensional wave phenomena. To store field values in individual SRAMs, efficient use of digital hardware resources is achieved and the engine is constructed by very small size hardware. Based on the design study, a prototype hardware is made and basic operation is confirmed

制御理論の学習と独創力向上を目的とした磁気浮上実験装置の開発と探求

金沢大学工学部本研究では学生が制御理論を学習し、また独創性を体感するための方法を実現することを目的とする。そのためにまず独創性について考え、その観点に基づき磁気浮上実験装置の製作を行う。例えばある着眼点を持って問題の設定を行い、その解決を試みる。それが大変に難しい場合であっても、可能性を追求し続けることで何らかのきっかけによる発想の転換があり、問題が解決されることがある。これは頭の中での発想を超える発想ということになるが、後から考えるとなるべくして成り立っていると思うことが多い。このような場合、独創を直感するということが重要であり、またこの独創する感覚を学ぶことは、これから技術者になろうとする者にとって大変な意義があると思われる。一方で、制御系について考えた場合、なるべくして成り立つような制御対象というものは意外に少ない。磁気浮上系もそのうちの一つになるが、この現象と装置自体を発想させることが、独創する感覚を得る、もしくはそのヒントになるのではないかと考えられる。まず磁気力によって鉄球を安定浮上させる問題を設定する。この系の数学モデルを考えた場合、現象を表す微分方程式は非線形となるが、安定浮上させることを考えると平衡点のみでモデルを考慮すればよい。解決手法は平衡点まわりでテーラー展開することであり、これにより線形制御理論を適用することが出来る。また、操作量としての磁気力を適切に与えるためには位置情報をフィードバックさせることが必要であり、これらの解決手法より磁気浮上装置の設計が可能となる。実験では極の配置を考えることで応答が変化することがわかり、制御理論について考察することができる。なお、装置は状態変数として電流値を含む3次の制御系となり、ギャップの変位速度については信号雑音も微分する恐れがあるためにオブザーバ併合レギュレータを製作した。研究課題/領域番号:19917009, 研究期間(年度):2007出典：「制御理論の学習と独創力向上を目的とした磁気浮上実験装置の開発と探求」研究成果報告書　課題番号19917009（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-19917009/)を加工して作

Initial Value Problem Formulation of 3-D Time Domain Boundary Element Method

A time domain boundary element method (TDBEM) gives us another possibility of time domain microwave simulations in addition to a finite difference time domain (FDTD) method. In particular, the TDBEM has good advantages in analysis of coupling problems with charged particle motion such as in a particle accelerator. However, it is known that time domain microwave simulations in the particle accelerator by the conventional TDBEM often encounter numerical instability and inaccuracy because of its bad matrix property. To avoid the numerical instability and inaccuracy caused by the conventional open boundary problem formulation of the TDBEM, an initial value problem formulation of 3-D TDBEM is presented in this paper

4-D Space-Time-Domain Decomposition Simulation of Particle Accelerator Wake Field Based on 3-D Time Domain BEM

A time-domain boundary element method (TDBEM) provides one more possibility of potential numerical schemes for a time domain microwave simulation in addition to the finite difference time domain method. However, it is known that the TDBEM requires very large memory of order of 100 GB. As one of the solutions to effective memory reduction, this paper presents a 4-D domain decomposition method for the TDBEM. It is shown that the 4-D domain decomposition method of the TDBEM works well for the effective memory reduction in a particle accelerator wake field analysis