Enhancing the color gamut of waveguide displays for augmented reality head-mounted displays through spatially modulated diffraction grating.

Augmented reality (AR) applications require displays with an extended color gamut to facilitate the presentation of increasingly immersive content. The waveguide (WG) display technology, which is typical AR demonstration method, is a critical constraint on the color gamut of AR systems because of the intrinsic properties of the holographic optical elements (HOEs) used in this technology. To overcome this limitation, we introduce a method of spatially modulated diffractive optics that can expand the color gamut of HOE-based WG displays. This approach involves spatial modulation using sub-pixelized HOEs, which enables the diffraction of red, green, and blue rays along identical directions. The proposed structure considers both the characteristics of the HOE and the wavelength sensitivity of the observer to optimize the color gamut. Consequently, an expanded color gamut was achieved. The results of the theoretical and experimental analyses substantiate the effectiveness and practicality of this method in enhancing the color gamut of HOE-based WG displays. Thus, the proposed method can facilitate the implementation of more immersive AR displays.

Stadium-type resonator sensor based on a multi-mode waveguide with mode discrimination phenomenon.

In this work, we present a multi-mode resonator based on SU-8 polymer and experimentally verify that the resonator showed mode discrimination can be used as a sensor with high performance. According to field emission scanning electron microscopy (FE-SEM) images, the fabricated resonator shows sidewall roughness which is canonically considered to be undesirable after a typical development process. In order to analyze the effect of sidewall roughness, we conduct the resonator simulation considering the roughness under various conditions. Mode discrimination still occurs even in the presence of sidewall roughness. In addition, waveguide width controllable by UV exposure time effectively contributes to mode discrimination. To verify the resonator as a sensor, we perform a temperature variation experiment, which results in a high sensitivity of about 630.8 nm/RIU. This result shows that the multi-mode resonator sensor fabricated via a simple process is competitive with other single-mode waveguide sensors.

Lipid Profiling of Pacific Abalone (Haliotis discus hannai) at Different Developmental Stages Using Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry.

Pacific abalone (Haliotis discus hannai) is a commercially important mollusk; therefore, improvement of its growth performance and quality has been emphasized. During embryonic development, abalones undergo a series of distinct larval stages, including swimming veliger larvae, juveniles, and mature individuals, and their biomolecular composition varies depending on the developmental stage. Therefore, in the present study, we performed untargeted lipid profiling of abalone tissues at different developmental stages as well as the hemolymph of mature female and male abalones using ultrahigh-performance liquid chromatography-tandem mass spectrometry. These profiles can provide meaningful information to understand compositional changes in lipids through abalone metamorphosis and development. A total of 132 lipids belonging to 15 classes were identified from abalone tissues at different developmental stages. Moreover, 21 lipids belonging to 8 classes were identified from the hemolymph of mature abalones. All data were processed following strict criteria to provide accurate information. Triglycerides and phosphatidylcholines were the major lipid components identified in both tissues and hemolymph, accounting for, respectively, 27% and 15% of all lipids in tissues and, respectively, 24% and 38% of all lipids in the hemolymph. Of note, lysophosphatidylcholine was only detected in the tissues of mature abalones, paving the way for further analyses of abalone lipids based on developmental stages. The present findings offer novel insights into the lipidome of abalone tissues and hemolymph at different developmental stages, building a foundation for improving the efficiency and quality of abalone aquaculture.

Nasalance scores for normal Korean-speaking adults and children: Effects of age, vowel context, and stimulus length.

OBJECTIVES: The purpose of this study was to collect nasalance scores for normal Korean-speaking children and adults and to determine whether age, vowel contexts, and stimulus length influence nasalance scores. METHODS: Fifty-seven children aged 4-6 years and 17 adults participated in the study. Mean nasalance scores were obtained for eight sentences devoid of nasal consonants divided into the vowel/a/and/i/contexts; the sentences consisted of 4, 8, 16, and 31 syllables. All subjects were asked to repeat the speech stimuli twice after the examiner. The headset of the nasometer was replaced between the first and second recordings. An average value of the nasalance scores from the two recordings for each stimulus was calculated and used in the statistical analysis as a representative measure for each subject. RESULTS: Mean and standard deviations of nasalance scores were obtained for each speech stimulus and each age group. The statistical analysis indicated significant effects of age and vowel context and a significant interaction between age and the vowel context on nasalance scores. However, the effect of stimulus length on nasalance scores was not significant. All speakers had higher nasalance scores for the vowel/i/contexts than for the vowel/a/contexts. Adults had higher nasalance scores compared to children in both vowel contexts. CONCLUSIONS: These normal nasalance values from Korean-speaking children aged 4-6 years will provide important reference information for resonance assessment of children with cleft palate who have been considered for secondary palatal surgery. The results of the study suggest that subjects' age and the vowel content of speech stimuli should be carefully considered when interpreting the nasalance scores.