Impact of load impedance on the performance of a thermoacoustic system employing acoustic pressure amplifier

An acoustic pressure amplifier (APA) is capable of improving the match between a thermoacoustic engine and a load by elevating pressure ratio and acoustic power output. A standing-wave thermoacoustic engine driving a resistance- and-compliance (RC) load through an APA was simulated with linear thermoacoustics to study the impact of load impedance on the performance of the thermoacoustic system. Based on the simulation results, analysis focuses on the distribution of pressure amplitude and velocity amplitude in APA with an RC load of diverse acoustic resistances and compliance impedances. Variation of operating parameters, including pressure ratio, acoustic power, hot end temperature of stack, etc., versus impedance of the RC load is presented and analyzed according to the abovementioned distribution. A verifying experiment has been performed, which indicates that the simulation can roughly predict the system operation in the fundamental-frequency mode.

論陳匪石詞

陳匪石的《宋詞舉》、《聲執》等詞學論著,近來學者已有論及,至於其詩詞創作則論之者尚少。本文首先結合其生平經歷、時代背景,綜論詞中的時代感及自我形象,然後梳理其詞學思想,以陳氏所推崇的吴文英、姜夔和周邦彦,探討陳匪石在創作時對經典的回應與創新。就整體評價而言,則本文以爲陳詞能顯示一代知識分子面對時局動蕩而感到難有作爲、慷慨悲憤的心靈紀録,在二十世紀的詞壇中佔有不可忽視的位置。