Fabrication and optical characterization of GaN quasi-phase matching crystal by double polarity selective area growth in metal organic vapor phase epitaxy

The fabrication of ultra-violet (UV) second-harmonic generation (SHG) (UV-SHG) devices requires GaN quasi-phase matching (GaN-QPM) crystals with periodically arranged polar GaN. For fabricating GaN-QPM crystals, the double polarity selective area growth (DP-SAG) using carbon mask technique is employed. However, the growth of narrow (2–4 [Formula: see text]m) pitch pattern GaN-QPM crystals, which is necessary for UV-SHG devices, has not been reported using this technique. Herein, we report the successful fabrication of 4 [Formula: see text]m pitch pattern GaN-QPM. We fabricated a thick GaN-QPM crystal at the optimized V/III ratio. Through optical characterization, we observed SHG generation from the GaN-QPM crystal fabricated using DP-SAG.

comparative prosodic study of questions in french in contact with occitan and catalan

In the south of France, the French language has developed in contact with Occitan in Provence and Languedoc, in contact with Catalan in Roussillon. This study reports on a first analysis of data collected in these regions, during a field survey carried out among speakers of Occitan and Catalan, in addition to French. In particular, we compared the prosody of yes/no questions ending in a word stressed on the penultimate syllable (e.g caserna ‘barracks’ in Occitan or Catalan, caserne with a pronounced final schwa in southern French). On the last two syllables of questions, it turns out that the rising-rising pitch pattern is the most common and, according to a perception experiment using prosody modification/resynthesis, that it is preferred to a falling-rising pattern by southern French listeners (without significant differences between Provence and Languedoc). A falling-rising pattern was also observed in Roussillon, possibly resulting from a prosodic transfer from Catalan to French. It was not associated with that region by southern French listeners who took part in a second perceptual experiment. Yet, the intonation patterns found may have different functions: the rising-rising pattern, especially, is most often interpreted as a confirmation query.

A typology of depiction marking

Ideophones and direct quotations are “depictive” signs, or vivid re-enactments of what they signify. Pursuing the typology of linguistic depiction, the current study proposes a three-way classification of depiction marking strategies: framing, foregrounding, and backgrounding. While well-known formal characteristics of ideophones, such as prosodic prominence and quotative constructions, illustrate framing and foregrounding, this paper discusses low-pitched quotative indexes in Japanese as backgrounding-type depiction markers. These quotatives immediately follow ideophones and exclamatory quotations and set them off. They also underlie the exceptional pitch pattern of heavy syllables in ideophones.

Hyper-articulation effects in Korean glides by heritage language learners

Aims and objectives: Hyper-articulation effects in glide sounds and heritage production are unexplored areas. Thus, this study examines how the Korean glide /we/ is phonetically implemented in hyper-articulated speech by English-speaking heritage learners of Korean. Language-specific fundamental frequency (F0) patterns and methodological issues involving inconsistent data in heritage research are also addressed. Methodology: Korean-American students enrolled in an intermediate-low Korean language course for Korean heritage students at a university in the US read four isolated sentences, once in casual speech and once in hyper-articulated (or clear) speech. They repeated this sequence five times. Data and analysis: The syllable duration of the glide more than doubled and the upward transitional feature of /w/ was significantly expanded with a steeper slope in clear speech compared to casual speech. The expansion of vowel space of /e/ in clear speech was also attested for second formant (F2). Although pitch did not vary between the two speaking styles at syllable onset or vowel midpoint, it exhibited a significant increase at syllable offset in clear speech. The strong intra- and inter-speaker variations frequently observed in heritage language research were not found in this study. Conclusions: The results generally echo the hyper-articulated speech changes observed in native Korean speakers. The pitch pattern outcomes suggest that heritage learners’ enhancement corresponds more to that of their heritage language than their dominant language. Although the data generally supports the idea that heritage learners’ enhancement strategies emulate those of native speakers in terms of exaggerated acoustic features, the same is not true regarding absolute acoustic values; their acoustic values are more exaggerated than native speakers’ in clear speech. Originality and implications: The findings present new hyper-articulation effects regarding glide sounds and an additional enhancement strategy of end-of-syllable pitch raising in hyper-articulated speech. This study also suggests that controlling for confounding population variables mitigates the methodological challenges of heritage language research.

Pitch Pattern Analysis in Speech of Children with Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a multifaceted neurodevelopmental condition. Atypical communication mostly occurs in tandem with ASD. We compared voice pitch of 16 Marathi children and adolescents with ASD of age of 7 to 18 with 27 Typically Developing (TD). Speech samples have been recorded and stored in .wav format with sampling frequency of 48000 Hz. For analysis we used PRAAT, a program for speech analysis, manipulation and synthesis. We divided the ASD and TD group into total 4 groups on basis of age and gender for comparison. We found that differences in voice pitch are present in these comparison groups, and male ASD group have more pitch variation than respective comparison groups. In future we look forward to include more ASD participants in study to increase the Marathi speech database for ASD.

Laser-Assisted Thermal Imprinting of Microlens Arrays—Effects of Pressing Pressure and Pattern Size

Polymer films with nano- or microstructured surfaces have been widely applied to optical devices, bioplates, and printed electronics. Laser-assisted thermal imprinting (LATI), in which a laser directly heats the surfaces of a mold and a thermoplastic polymer, is one of the high-throughput methods of replicating nano- or microstructures on polymer films. Only the surfaces of the mold and polymer film are heated and cooled rapidly, therefore it is possible to replicate nano- or microstructures on polymer films more rapidly than by using conventional thermal nanoimprinting. In this study, microlens arrays (MLAs) were replicated on polymethylmethacrylate (PMMA) films using LATI, and the effects of the pressing pressure (10−50 MPa) and the pattern size (33- and 5-μm pitch) of the MLA on the filling ratio were investigated by analyzing a microlens replicated using different laser-irradiation times (0.1−2 ms). The filling ratio increased with increasing pressing pressure and laser-irradiation time in the replication of MLAs with varying sizes, while the flow of the PMMA varied with the pressing pressure and laser-irradiation time. It was found that during filling, the shape of the polymer cross-sectional surface demonstrated a double and single peak in the 33- and 5-μm-pitch patterns, respectively. This was because the depth of the heated area in the 33-μm-pitch pattern was smaller than the pattern size, whereas that of the 5-μm-pitch pattern was comparable to (or larger) than the pattern size.

THE PROSODY OF IMPERATIVE SENTENCES IN EVENKI AND OROCHON: PITCH

Imperative sentences in Evenki and Orochon are undoubtedly a challenging issue of their grammar and phonetics. The aspects, on which researchers' opinions diverge, include grammar tense, neutral and inverted word order and prosodic arrangement of the sentences. It is the only type of sentences with the verb in sentences-initial position. Among 14 imperative verb forms (they change in 2 tenses with varying names, 3 persons and 2 numbers; some of them have inclusive and exclusive forms), 2nd-person forms in the Present Tense are characterized by the highest frequency of occurrence. This paper reports the results of an acoustic study of pitch movement in Evenki and Orochon imperative sentences depending on the number of words, syllables and the word order. The following results were obtained. In the Evenki material, two- and three-word syntagmas were characterized mostly by rise-fall pitch pattern while one-word syntagmas could have both rise-fall and fall patterns. Four-syllable-one word syntagmas' pattern was pitch declination while two- and three-syllable-one-word syntagmas could have both rise-fall and declination patterns with similar frequency of occurrence...