The solar system began as a disk of dust and gas swirling around the young sun. 太陽(yáng)系一開(kāi)始是一個(gè)由灰塵和氣體組成的圓盤(pán)，圍繞年輕的太陽(yáng)旋轉。
The PQR shall include the composition and flow rate of the shielding and inert gas backing, when used. 焊接工藝評定記錄單上應包括封底焊時(shí)所用的惰性保護氣體組成成分和流率。
A new method for recognizing gas components in air based on nonlinear fluorescence spectra combined with a neural network model was proposed. 提出利用物質(zhì)的熒光光譜聯(lián)合人工神經(jīng)網(wǎng)絡(luò )識別大氣中雜質(zhì)氣體成分的新方法。
