Optimization of Gold Nanoring Arrays for Biosensing in the Fiber-optic Communication Window

To improve the limit of detection in a nanoplasmonic sensor system, the optical performance of the metal nanostructures should be optimized according to the best spectral window of the measurement instrument. We propose that the spectral window from 1460 to 1610 nm can potentially provide ultrahigh instrumental resolution for biosensing. We optimized gold nanoring arrays such that the extinction peak position is inside the proposed window, the extinction peak is sharp enough to track the peak shift with high resolution and the figure of merit (sensitivity/linewidth) of the array is optimized at the same time. The peak-sharpening effect of the array caused by coherent interaction plays a central role in the optimization. The optimized array has a lattice constant in the range [1000 nm; 1060 nm], a bulk index sensitivity of around 450 nm=RIU and a figure of merit larger than 4. It is an enabling sensor element for a nearinfrared sensor chip with ultrahigh resolution

A Biosensor based on Periodic Arrays of Gold Nanodisks under Normal Transmission

We present a biosensor based on periodic arrays of gold nanodisks patterned on top of a glass substrate. The sensor’s resonance wavelength, peak linewidth and figure of merit were studied both in experiments and in simulations. We analyzed the dependence of the sensor’s resolution on the inherent figure of merit of the sensor structure and the signal to noise ratio of the detection system. The best achieved refractive index resolution is 1.5×10-4 RIU and the detection limit on and antigen-antibody binding is better than 1 ng/mL

Electrohydrodynamic Drying of Chinese Wolfberry in a Multiple Needle-to-Plate Electrode System

In order to systematically and comprehensively investigate electrohydrodynamic (EHD) drying characteristics and mechanisms in a multiple needle-to-plate electrode system, drying experiments of Chinese wolfberry were conducted by blocking ionic wind and changing needle spacing in a multiple needle-to-plate electrode system. Drying characteristics, quality parameters, and the microstructure of Chinese wolfberry fruits were measured. Results show that ionic wind plays a very important role during the drying process. Drying rates of different needle spacing treatments are significantly higher than that of the control, and the drying rate decreases with the increase of needle spacing. Needle spacing has a great influence on the speed of ionic wind, rehydration rate, and polysaccharide contents. The effective moisture diffusion coefficient and the electrical conductivity disintegration index decreases with an increase in needle spacing. Ionic wind has a great influence on the effective moisture diffusion coefficient and the electrical conductivity disintegration index of Chinese wolfberry fruits. The microstructure of Chinese wolfberry fruits dried in an EHD system significantly changed. This study provides a theoretical basis and practical guidance for understanding characteristic parameters and mechanisms of EHD drying technology

Infrared Spectrum Analysis of Goji Berry during Electrohydrodynamic Drying

This paper aims to study the effects of different needle spacings on goji berry structure during electrohydrodynamic (EHD) drying. The drying characteristics and the product quality parameters of goji berry during the drying process were measured. The infrared spectrum of the dried product was analyzed in detail. The results showed that the average drying rate of goji berry under different needle spacing conditions was significantly higher than that of the control group, and the average drying rate decreased with the increase of needle spacing. The change of needle spacing has great influence on goji berry polysaccharide content and flavonoid content. Fourier transform infrared spectroscopy showed that the infrared spectra of goji berry in each treatment group were generally similar. The first-order infrared spectra of different treatment groups were mainly different in the range of 1740 cm−1 and 2800 cm−1–2950 cm−1. The shape and intensity of the absorption peaks of the second derivative infrared spectrum of goji berry in different needle spacing treatment groups were different. When the needle spacing is 2 cm and 4 cm, there is a highly variant peak ratio and a low common peak ratio, which proves that the best drying effect is at 2 cm and 4 cm. It provides experimental and theoretical basis for the study of the application and drying mechanism of infrared spectroscopy in the field of electrohydrodynamic drying

Factors Influencing the Properties of Extrusion-Based 3D-Printed Alkali-Activated Fly Ash-Slag Mortar

The mix proportioning of extrusion-based 3D-printed cementitious material should balance printability and hardened properties. This paper investigated the effects of three key mix proportion parameters of 3D-printed alkali-activated fly ash/slag (3D-AAFS) mortar, i.e., the sand to binder (s/b) ratio, fly ash/ground granulated blast-furnace slag (FA/GGBS) ratio, and silicate modulus (Ms) of the activator, on extrudability, buildability, interlayer strength, and drying shrinkage. The results showed that the loss of extrudability and the development of buildability were accelerated by increasing the s/b ratio, decreasing the FA/GGBS ratio, or using a lower Ms activator. A rise in the s/b ratio improved the interlayer strength and reduces the drying shrinkage. Although increasing the FA/GGBS mass ratio from 1 to 3 led to a reduction of 35% in the interlayer bond strength, it decreased the shrinkage strain by half. A larger silicate modulus was beneficial to the interlayer bond strength, but it made shrinkage more serious. Moreover, a simple centroid design method was developed for optimizing the mix proportion of 3D-AAFS mortar to simultaneously meet the requirements of printability and hardened properties