220,062 research outputs found
Chao Yuen Ren (1892–1982)
No full textY. R. Chao is easily the most famous linguist to have come out of China. Born before the end of the last dynasty in China, he received a traditional Confucian education, but was also one of the first Chinese people to be sent to the West for training in modern Western science (under the Boxer Indemnity Fund). The remarkable breadth and scope of his studies included physics, mathematics, linguistics, musical and literary composition, and translation, and he was a pioneer in many of these fields
Energy harvesting from a convection-driven Rijke-Zhao thermoacoustic engine
No full textA convection-driven Rijke-Zhao thermoacoustic engine is developed. It can produce intensive oscillations at two different temperatures. Furthermore, it does not involve any heat exchanger and stack/regenerator, which play critical roles in conduction-driven standing- or travelling-wave engines. Thus, the Rijke-Zhao engine is much simpler in design and lower cost in fabrication. To demonstrate its potential of energy-harvesting, a design for the conversion of heat into electricity via sound is proposed by integrating Rijke-Zhao engine with a piezoelectricgenerator. The preliminary experimental results are presented. And it is found that 60% more power is generated than that from conduction-driven standing-wave thermoacoustic-piezoelectric resonator [Smoker et al., J. Appl. Phys. 111, 104901, (2012)]. In order to gain insights on the generation mechanism of the thermoacoustic oscillations in the present energy-harvesting system, 2D numerical simulations are conducted. Comparing the numerical results with the experimental one reveals that good quantitative agreement is obtained.MOE (Min. of Education, S’pore)Published versio
Experimental measurement of combustion instabilities in Rijke-Zhao tubes
No full textThis project aims to investigate the onset and selection of combustion-excited oscillations in uniquely configured combustion systems through experimental approaches such as thermal imaging and flow visualization. The insights gained on the behavior of such combustion systems can be used in future researches to develop control methodologies to minimize and eliminate combustion instability, or to improve efficiencies in applications such as industrial dryers and engine systems. In this paper, the theoretical concept of pulse combustion will also be explained and demonstrated.
The experimental set-up consists of Rijke-Zhao tubes of various configurations, being placed vertically above a flame. The Rijke-Zhao tubes are made of quartz and they are Y-shaped, with configurations varying in terms of the branch lengths and angles. High speed camera at 20 frames per second (fps) was used to capture flow motion within the quartz tubes, while infrared camera was used to display the temperature distribution. To measure the pressure field within the tube, two arrays of microphones were strategically positioned along the upper branches. Finally, a flow anemometer and a K-type thermocouple were used to measure the flow velocity and flow temperature at the ends of the branches respectively. The results gathered were tabulated and analyzed.Bachelor of Engineering (Aerospace Engineering
Lyophyllum pallidofumosum Y. H. Ma, W. M. Chen & Y. C. Zhao 2022, sp. nov.
No full textLyophyllum pallidofumosum Y. H. Ma, W. M. Chen & Y. C. Zhao sp. nov. (Figs. 1A, 3) MycoBank: MB 844903 Etymology: — pallidofumosum, refers to the morphological similarity of the new species to L. fumosum. Diagnosis:— Lyophyllum pallidofumosum differs from the other species of the L. decastes complex by a greyish orange pileus surface, margin with waves when old; globose to subglobose basidiospores (4.5–5.6 × 4.3–5.4 µm), clavate basidia (25–34 × 7–9 µm); occurring in a mixed forest dominated by Pinus yunnanensis, Pinus armandi, and Quercus fabrei; and the highest growth rate on the YPD medium,. Holotype:— CHINA, Yunnan Province, Xuanwei City, Reshui Town, in a mixed forest, 25°58′17″ N, 103°44′50″ E, elev. 2344m, 09 September 2021, Yuanhao Ma, Weimin Chen, Ping Liu, 21rs0242 (HKAS 124190) Description:—pileus 20–60 mm in diam., Pileus shape convex and margin involute when young, applanate, margin waves when old. Pileus colour slightly desaturated orange (5B3–5), greyish orange (6B5), oak brown (5D5–6). Lamellae adnate or subdecurrent. Lamellae colour white (5A1) to light greyish orange (5B2). Context white to whitish. Stipe cylindrical slightly enlarged towards base, central, solid, tough in texture, 30–80 × 8–15 mm. Stipe colour white (5A1) to light greyish orange (5B2). Basidiospores hyaline, globose to subglobose, smooth, with a single large oil-drop and a small apiculus, (4.26–) 4.55–5.54 (–5.76) × (4.15–) 4.30–5.36 (–5.57) µm, (m/n/p=113/6/2, l m =5.06 ± 0.31µm, w m =4.83 ±0.31µm), Q= (1.00–) 1.01–1.11 (–1.12), Q m =1.05 ±0.32. Basidia 4-spored, clavate, sometimes ventricose, (24.10–) 25.53–33.50 (–35.36) × (6.78–) 7.09–8.78 (–9.63) µm, l m =29.08 ± 2.31µm, w m =7.89 ±0.55µm, Q= (2.93–) 3.15–4.24 (–4.44), Q m =3.70 ±0.34; sterigmata 1.77–3.87 µm long. Some with clamp connections. Lamellae without cheilocystidia and pleurocystidia. Colonies 43–45 mm radius after 24 d at 22℃ in the dark on YPD, white, downy to cottony with loose aerial hyphae; some with clamp connections. Habitat:—solitary, gregarious or cespitose on the ground as saprobic in a mixed forest dominated by Pinus yunnanensis, Pinus armandi, and Quercus fabrei. Additional specimens examined:— CHINA, Yunnan Province, Xuanwei City, Reshui Town, in a mixed forest, 25°58′17″ N, 103°44′50″ E, elev. 2344m, 24 July 2019, YAASM6138 (HKAS 124189, Paratype); ibid., Shangri-La County, 16 October 2020, YAASM6215; ibid., 26 July 2006, yang 4742 (HKAS 50539); ibid., Lanping County, Jinding Town, 15 October 2011, zhao 1334 (HKAS 74287). Ex-type: YAASM6628 and YAASM6629, isolated from the inner tissues of two basidiomata. Ex-type sequences:— YAASM6628/HKAS124190a = LSU: ON834576, ITS: ON680829; YAASM6629/ HKAS124190b = LSU: ON834577, ITS: ON680830.Published as part of Ma, Yuanhao, Liu, Ping, Zhao, Ziyue, Chen, Weimin & Zhao, Yongchang, 2022, Lyophyllum pallidofumosum sp. nov. (Lyophyllaceae, Agaricales), from southwestern China, pp. 173-183 in Phytotaxa 576 (2) on page 178, DOI: 10.11646/phytotaxa.576.2.3, http://zenodo.org/record/746126
Nanoimprint lithography for planar chiral photonic meta-materials
No full textRoom temperature nanoimprint lithography has successfully been applied to the fabrication of planar chiral photonic meta-materials. For dielectric chiral structures a single layer of thick HSQ was used while for metallic chiral structures a bi-layer technique using PMMA/hydrogen silsequioxane (HSQ) was applied. The polarization conversion capabilities of planar chiral structures imprinted in dielectric materials have experimentally been observed. This indicates that the developed processes in this work have the prospect of manufacturing planar photonic meta media in high volume at low cost
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