Design of polarization splitter and rotator using function-expansion based topology optimization considering two-layer structure

Function expansion based topology optimization method for optical waveguide devices has been proposed as an automatic design method which can produce an optimal device structure having an arbitrary topology. In this paper, we aim to extend the function expansion based topology optimization method to the design problems of three-dimensional photonic devices with structural variation in the depth direction. We confirm the effectiveness of our approach through the design example of the polarization splitter and rotator which utilizes structural asymmetry in the depth direction

Topology optimization of nonlinear optical waveguide devices considering output signal phase

A signal output of optical devices with multi-input ports, such as a logic gate, depends on the phase difference between input ports. In order to cascade optical devices, it is essential to design such devices considering not only desired output power but also desired output signal phase. We propose a topology optimization method for optical devices considering the output signal phase. In our approach, the beam propagation method (BPM) is employed as a numerical simulation method and the adjoint variable method (AVM) is used to calculate the sensitivity of output power and signal phase to design parameters. The validity and the effectiveness of our approach are verified through design examples of a three-branching waveguide with linear media and an all-optical logic gate utilizing nonlinear media

Kidney- and Site-Selective Delivery of 5-Fluorouracil Utilizing the Absorption on the Kidney Surface in Rats

The present study was undertaken to elucidate the kidney- and site-selective delivery of 5-fluorouracil (5-FU) utilizing the absorption on the kidney surface in rats. An experimental system utilizing a cylindrical diffusion cell attached to the right kidney surface was established. After intravenous administration of 5-FU, the concentration of 5-FU in the right and left kidneys was almost the same and was rapidly eliminated. After right kidney surface application of 5-FU, however, the concentration of 5-FU in the right kidney was significantly higher than in the left kidney and other tissues. The 5-FU concentration in four sites of the right kidney after intravenous administration was almost the same. In contrast, 5-FU was site selectively delivered in the kidney after kidney surface application. The blood concentration of 5-FU was low (<1.7 μg/ml) until 120 min after kidney surface application. The maximum blood concentration of 5-FU after kidney surface application was much lower than after intravenous administration

Characteristic Properties of Lignite To Be Converted to High-Strength Coke by Hot Briquetting and Carbonization

A sequence of hot briquetting and carbonization (HBC) is a promising technology for the production of coke with a high mechanical strength from lignite, but factors affecting the coke strength have not yet been fully understood. The HBC cokes prepared from 12 lignites in this study showed diverse tensile strength (e.g., from 0.2 to 31.2 MPa in the preparation at 200 °C and 112 MPa for hot briquetting and 1000 °C for carbonization), and the coke strengths could not be explained by differences in commonly used structural properties of the parent lignites, such as elemental composition and contents of volatile matter/fixed carbon and ash. In this study, two methods were proposed for correlating the coke strength with the lignite properties, which employed the chemical structure analyzed by solid-state ¹³C nuclear magnetic resonance or the volumetric shrinkage during carbonization. A stronger coke was obtained from lignite that contained more aliphatic carbons (less aromatic carbons) or shrank more considerably. These characteristics contributed to intensified compaction of lignite in the briquetting and suppression of the formation of large pores, which are a cause of coke fracture. Two empirical equations, predicting the coke strength from the parameters of lignite properties, were established to be criteria for selection of lignite as HBC coke feedstock, although further investigation with more experimental data would be necessary for the validation