There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The path of chemical reactions - the IRC approach

Since the 3rd century for more than a thousand years chemistry has been thought of as a complicated, hard-to-predict science. Efforts to improve even a part of its unpredictable character are said to have born fruit first of all in the success of the \" electronic theory \". This was founded mainly by organic chemists , such as Fry, Stieglitz, Lucas, Lapworth and Sidgwick, brought to a completed form by Robinson and Ingold, and developed later by many other chemists. 1 In the electronic theory, the mode of migration of electrons in molecules is noted and is considered under various judgements. For that purpose, a criterion is necessary with respect to the number of electrons which should originally exist in an atom or a bond in a molecule. Therefore, it can be said to be the concept by Lewis of the sharing of electrons that has given a firm basis to the electronic theory. 2 In the organic electronic theory, the chemical concepts such as acid and base, oxidation and reduction and so on, have been conveniently utilized from a long time ago. Furthermore, there are terms centring closer around the electron concept, such as electrophilicity and nucleophilicity, and electron donor and acceptor both being pairs of relative concepts. One may be aware that these concepts can be connected qualitatively to the scale of electron density or electric charge. In the electronic theory, the static and dynamic behaviours of molecules are explained by the electronic effects which are based on nothing but the distribution of electrons in a molecule. The mode of charge distribution in a molecule can be sketched to some extent by the use of the electronegativity concept of atoms through organic chemical experience. At the same time, it is given foundation, made quantitative , and supported by physical measurements of electron distribution and theoretical calculations based on quantum theory. The distribution of electrons or electric charge-with either use the result is unchanged-in a molecule is usually represented by the total numbers (generally not integer) of electrons in each atom and each bond, and it was a concept easily acceptable even to empirical chemists as having a tolerably realistic meaning. Therefore, chemists employed the electron density as a fundamental concept to explain or to comprehend various phenomena. In particular, for the purpose of promoting chemical investigations, researchers usually rely upon the analogy through experience, and the electron density …

https://science.sciencemag.org/content/sci/218/4574/747.full.pdf

Role of Frontier Orbitals in Chemical Reactions

The ability of platinum and gold catalysts to effect powerful atom-economic transformations has led to a marked increase in their utilization. The quite remarkable correlation of their catalytic behavior with the available structural data, coordination chemistry, and organometallic reactivity patterns, including relativistic effects, allows the underlying principles of catalytic carbophilic activation by π acids to be formulated. The spectrum of reactivity extends beyond their utility as catalytic and benign alternatives to conventional stoichiometric π acids. The resulting reactivity profile allows this entire field of catalysis to be rationalized, and brings together the apparently disparate electrophilic metal carbene and nonclassical carbocation explanations. The advances in coupling, cycloisomerization, and structural reorganization—from the design of new transformations to the improvement to known reactions—are highlighted in this Review. The application of platinum- and gold-catalyzed transformations in natural product synthesis is also discussed.

Catalytic Carbophilic Activation: Catalysis by Platinum and Gold π Acids

In-Wheel Motor (IWM) which is a driving system of Electric Vehicles (EVs) is effective for expanding driving range and reducing vehicle weight. However, IWM has not been put in practical use because of a possibility of power lines disconnection. Therefore, we have proposed Wireless In-Wheel Motor (W-IWM) in which Wireless Power Transfer (WPT) is used to remove these lines and to enhance practicability of IWM. Moreover, we have proposed the advanced system of W-IWM which has Lithium-ion Capacitor (LiC) and circuit on its wheel side for dynamic charging. In this paper, a State of Charge (SOC) control of LiC on the wheel side in the advanced system is proposed. By applying the proposed control, the SOC control of the LiC and power management on the wheel side are achieved simultaneously. The proposed control is verified by simulations and experiments.

Power management of Wireless In-Wheel Motor by SOC control of wheel side Lithium-ion Capacitor

The developments in position control methods have enabled us to obtain a rapid response or high control bandwidth for improving control performance. However, there is an emerging problem in which a control system with a high control bandwidth may excite mechanical vibration, which deteriorates control performance. This is the case especially in a mechanism that has a flexible joint between the motor and the load, such as the feeding tables of machine tools, the arms of industrial robots, and rolling mills. Therefore, there is a strong demand for vibration suppression control with a high control bandwidth while maintaining productivity. For high-precision control of a two-inertia system, the position information of both the motor side and load side is usually required to obtain a high control bandwidth. In order to reduce the implementation cost and space, a novel control method, which employs the load-side information only, is proposed using a high-resolution encoder. Simulation and experimental results demonstrate that the proposed method is implementable and exhibits good control performance.

Vibration suppression control of two-inertia system without using drive-side information by applying high-resolution encoder

High-precision stages are industrial equipment for micro-fabrications. Fast and precise positioning control is very important technology related to the improvement of the throughput and the product quality. Especially, a large-scale stage has a low resonance mode which disturbs fast and precise positioning because of the structures of the stage. In this paper, a novel feedback system is proposed in a SIMO system using multiple position sensors which are located at an actuator side and a load side. The proposed feedback system has two remarkable features. One is that the effect of the vibration suppression and the phase stabilization of the resonance mode can be tuned simultaneously only by two parameters. The other is that the tuning of the resonance mode does not affect the rigid mode at all. Finally, simulations and experiments with a XY -gantry-stage are performed to show the advantages of the proposed feedback control system.

Frequency separation self resonance cancellation for vibration suppression control of a large-scale stage using multiple position sensors

In a short-span seeking-mode of hard disk drives, the two-degree-of-freedom control is generally used. Authors' group proposed the perfect tracking control (PTC) method in order to achieve high accuracy and high speed controlling. We also proposed the learning PTC method which can suppress the overshoot by learning the tracking error in acceleration and deceleration period. In this paper, we propose the developed method named “Integral Type Learning PTC” which can suppress the overshoot higher by integral type learning of the trajectory tracking error.

Short-span seeking control of hard disk drive based on integral type learning PTC

Among many vehicle states, body slip angle is one of the most important information for vehicle motion control. Due to the high costs to measure body slip angle with specific devices, it is necessary to investigate estimation methods using existing cheap sensors. From the viewpoint of sensor configuration, gyroscope, steering angle sensor, etc. are often employed for body slip angle estimation; in this research, two pieces of information provided by vision system are also utilized as additional measurements. Nevertheless, the sampling rate of normal camera is much slower compared to the other kinds of onboard sensors; for electric vehicles (EVs), motors' control period is shorter than the sampling time of cameras, which also brings multi-rate issue. Moreover, the time delay caused by image processing is usually too long to be neglected. In this paper, single-rate and multi-rate Kalman filters considering measurement delay are designed for body slip angle estimation, and a body slip angle controller is designed with the estimated result as feedback. First of all, vehicle model and visual model as well as the multi-rate and delay issues are explained; then, single-rate and multi-rate Kalman filters are designed for body slip angle estimation; and then, body slip angle controllers with single-rate and multi-rate estimators are compared followed with simulations and experimental results; finally, conclusion and future works are presented.

/pdf/vision-based-multi-rate-estimation-and-control-of-body-slip-7zsje4io7a.pdf

Hiroshi Fujimoto

Papers

Power management of Wireless In-Wheel Motor by SOC control of wheel side Lithium-ion Capacitor

Vibration suppression control of two-inertia system without using drive-side information by applying high-resolution encoder

Frequency separation self resonance cancellation for vibration suppression control of a large-scale stage using multiple position sensors

Short-span seeking control of hard disk drive based on integral type learning PTC

Vision based multi-rate estimation and control of body slip angle for electric vehicles