Engineering molecular aggregate spectra

We show that optical properties of linear molecular aggregates undergo drastic changes when aggregates are deposited on a metal surface. The dipole-dipole interactions of monomers with their images can result in strong {re-structuring of both the exciton band and the absorption spectrum, depending on the arrangement of the monomer transition dipoles with respect to the surface.Comment: 4 two-column pages, Proceedings of the 8th International Conference on Excitonic Processes in Condensed Matter, June 22-27, Kyoto, Japa

Exciton Dephasing and Thermal Line Broadening in Molecular Aggregates

Using a model of Frenkel excitons coupled to a bath of acoustic phonons in the host medium, we study the temperature dependence of the dephasing rates and homogeneous line width in linear molecular aggregates. The model includes localization by disorder and predicts a power-law thermal scaling of the effective homogeneous line width. The theory gives excellent agreement with temperature dependent absorption and hole-burning experiments on aggregates of the dye pseudoisocyanine.Comment: 11 pages, 3 PostScript figure

The J- and H-bands of dye aggregate spectra: Analysis of the coherent exciton scattering (CES) approximation

The validity of the CES approximation is investigated by comparison with direct diagonalisation of a model vibronic Hamiltonian of $N$ identical monomers interacting electronically. Even for quite short aggregates (N\gtrsim 6) the CES approximation is shown to give results in agreement with direct diagonalisation, for all coupling strengths, except that of intermediate positive coupling (the H-band region). However, previously excellent agreement of CES calculations and measured spectra in the H-band region was obtained [A. Eisfeld, J. S. Briggs, Chem. Phys. 324, 376]. This is shown to arise from use of the measured monomer spectrum which includes implicitly dissipative effects not present in the model calculation

Two-Dimensional Electronic Spectroscopy of Chlorophyll a: Solvent Dependent Spectral Evolution

The interaction of the monomeric chlorophyll Q-band electronic transition with solvents of differing physical-chemical properties is investigated through two-dimensional electronic spectroscopy (2DES). Chlorophyll constitutes the key chromophore molecule in light harvesting complexes. It is well-known that the surrounding protein in the light harvesting complex fine-tunes chlorophyll electronic transitions to optimize energy transfer. Therefore, an understanding of the influence of the environment on the monomeric chlorophyll electronic transitions is important. The Q-band 2DES is inhomogeneous at early times, particularly in hydrogen bonding polar solvents, but also in nonpolar solvents like cyclohexane. Interestingly this inhomogeneity persists for long times, even up to the nanosecond time scale in some solvents. The reshaping of the 2DES occurs over multiple time scales and was assigned mainly to spectral diffusion. At early times the reshaping is Gaussian-like, hinting at a strong solvent reorganization effect. The temporal evolution of the 2DES response was analyzed in terms of a Brownian oscillator model. The spectral densities underpinning the Brownian oscillator fitting were recovered for the different solvents. The absorption spectra and Stokes shift were also properly described by this model. The extent and nature of inhomogeneous broadening was a strong function of solvent, being larger in H-bonding and viscous media and smaller in nonpolar solvents. The fastest spectral reshaping components were assigned to solvent dynamics, modified by interactions with the solute

Analysis and Design of Solar Power System Interface Utility Using ZVS Converter

The solar power generation system with minimal losses, high simplicity and easy control is attempted in this work, by developing a grid-tied zero-voltage switching (ZVS) inverter with a less number of power conversion stages and the least count of passive components, for single-phase applications that are suitable for conversion from low-voltage DC (40-60 V) to line voltage AC (230 VAC; RMS) at average power levels of 175 W and below. The ZVS full-bridge inverter fed from a PV panel is working on higher frequency with an asymmetric auxiliary circuit, which guarantees ZVS at the switching instants of the metal-oxide-semiconductor field-effect transistors (MOSFETs) by supplying the reactive current to these full-bridge semiconductor switches and reducing the switching losses. Checking of the constructional workability and analytical feasibility of the proposed topology with the highest efficiency and the simplest control was the target of this work, which was set on the basis of the results obtained in the MATLAB Simulink environment. The control strategies were planned for the optimum value of the reactive current injected by the auxiliary circuit to guarantee ZVS and use of phase shifted pulsewidth modulation (PWM) with varying frequencies for the full-bridge inverter and half-bridge cyclo-converter. The hybrid maximum power point tracking (MPPT) was part of this plan used to set the power at its maximum value against the environmental changes.Citation: Deshbhratar, R. G., and Renge, M. M. (2018). Analysis and Design of Solar Power System Interface Utility Using ZVS Converter. Trends in Renewable Energy, 4, 83-101. DOI: 10.17737/tre.2018.4.3.005

Operation of Symmetrical and Asymmetrical Two-Phase Induction Motor by Using 3-Leg Voltage Source Inverter

The importance and demand of renewable energy have increased rapidly, especially due to the fact that the fossil fuels are reducing at an alarming rate. Out of the existing sources of renewable energies, solar energy has been very popular due to obvious abundance and convenience. The predominant use of electrical energy is heating, ventilation and air conditioning in residential and industrial sector. Single phase induction motor is widely used for such low-power appliances like pumps, compressors, agriculture equipment’s and blowers. In order to avoid losses and low-starting torque, we intend to use the single-phase induction motor as an asymmetrical two-phase induction motor, which will run on a two-phase supply yielding better efficiency, speed control and power factor. If a three-phase supply is available, Scott-T transformer can be used to get two-phase supply. However, if there is only single-phase supply available, two-phase inverter with Sine Pulse Width Modulation (SPWM) technique can be used. This paper presents the method for two-phase supply using the 3-leg voltage source inverter (VSI) which is used to supply asymmetrical and symmetrical two-phase induction motor. The 16 bit microcontroller dsPIC is used for SPWM signal generation.Citation: Umredkar, S. V., Junghare, A., and Renge, M. (2018). Operation of Symmetrical and Asymmetrical Two-Phase Induction Motor by Using 3-Leg Voltage Source Inverter. Trends in Renewable Energy, 4, 64-76. DOI: 10.17737/tre.2018.4.3.005

Cross-cultural effects on drivers' hazard perception

Hazard perception tests are used in several developed countries as part of the driver licensing curriculum, however little research has been done in developing countries where road safety is a primary concern. We conducted a cross-cultural hazard perception study to examine the transferability of hazard perception skills between Malaysia and the UK, using hazard clips filmed in both countries. The results showed that familiarity with both the driving environment and type of hazard facilitated drivers' ability to discriminate hazards in a timely manner, although overall drivers viewed and responded to hazards largely similarly regardless of origin. Visual strategies also appeared to be moderated mainly by the immediate driving environment rather than driver origin. Finally, Malaysian drivers required a higher threshold of danger than UK drivers before they would identify a situation as hazardous, possibly reflecting the more hazardous road environment in Malaysia. We suggest that hazard perception testing in developing countries requires a test where performance cannot be confounded with differing thresholds for hazardousness

Metal-Organic Covalent Network Chemical Vapor Deposition for Gas Separation

The chemical vapor deposition (CVD) polymerization of metalloporphyrin building units is demonstrated to provide an easily up-scalable one-step method toward the deposition of a new class of dense and defect-free metal–organic covalent network (MOCN) layers. The resulting hyper-thin and flexible MOCN layers exhibit outstanding gas-separation performances for multiple gas pairs.United States. Army Research Office. Institute for Soldier Nanotechnologies (Contract DAAD-19-02D-0002)Luxembourg National Research Fun

Optimal DSSC’s deployment in power system using PSO

Owing to the high cost of installation and operation, distributed flexible AC transmission system (FACTS) technology gives opportunity to provide cost-effective solution in power system operation and control. A distributed static series compensator (DSSC) is a series FACTS device and it is placed equidistantly placed on the existing line to vary the line current. Active power can be controlled in the line with the help of DSSC. This paper presents DSSC for active power flow control to enhance system loadability index and to minimize reactive power generation by generators. Since DSSC is of low power. a small value of reactance is emulated in the line. Large number of DSSC’s are distributed along the transmission line at regular intervals to realize considerable change in the current. A particle swarm optimization is implemented to determine DSSC’s emulated reactance optimally. In this condition, all the lines flowing power in their limits with increased loading condition. Maximum system loadability index is evaluated by employing optimal number of DSSC’s on the line. A multiobjective problem is formulated. One objective function is formed such that no line would become overloaded even when loading is increased. Other objective is formulated to minimize reactive power generation by generators. A compromise solution is investigated for optimally connected of DSSC devices to achieve both the objective functions. IEEE 14 bus system is taken for MATLAB simulation of DSSC compensated system

新卒訪問看護師が自己成長感を獲得する経験

滋賀医科大学修士（看護学）令和5年度thesi