useful adj. 1.有用的,有益的,有效的,有幫助的。 2.〔俚語〕值得稱贊的,精通…的 (at)。 make oneself generally useful 事事有用,事事幫得來忙 (He must make himself generally useful. 他可事事都干得來)。 a pretty useful performance 相當(dāng)精采的演出。 His wife is very useful at cooking. 他的妻子很會做菜。 adv. -ly ,-ness n.
quantity n. 1.量 (opp. quality); 分量,數(shù)量;額;【物理學(xué)】值,參量。 2.〔pl.〕大量,大宗,大批,許多。 3.定量,定額。 4.【數(shù)學(xué)】量;表示量的數(shù)字[符號];【邏輯學(xué)】(名詞、特別是命題主語的)量。 5.【音韻學(xué)】音節(jié)的長短;表示音節(jié)長短的符號;【語音】(元[母]、音節(jié)等的)音量。 6.【法律】期限。 a known quantity 已知數(shù)。 an unknown quantity 未知數(shù);〔比喻〕難預(yù)測的人[物]。 a negligible quantity 可忽略的量;〔比喻〕無足輕重的人〔物〕;可忽略的因素。 a quantity of 一些。 in quantities 大量。 in quantity 很多。
A very useful quantity is the half-time for the reaction . 一個很有用的量是反應(yīng)的半衰期。
Br > useful quantities have changed hands 較大的數(shù)量已經(jīng)轉(zhuǎn)手。
Useful quantities have changed hands 較大的數(shù)量已經(jīng)轉(zhuǎn)手。
Useful quantities have changed hands 較大的數(shù)量已經(jīng)轉(zhuǎn)手
Abstract : in this paper ? for real marine underwater noise data by using synchronous acquisition of points ? inputs - output covariance matrix is obtained by filtering ? compensating delay and crosscorrelation . then the contribution of inputs to output in network sense and partial coherence as well as other useful quantities are calculated from the inputs - output covariance matrix 文摘:本文對多點同步測量方法記錄的艦艇噪聲數(shù)據(jù),采取在時域上作濾波、時延補償和互相關(guān)得到輸入輸出協(xié)方差矩陣,然后從輸入輸出協(xié)方差矩陣計算在網(wǎng)絡(luò)意義和偏相干意義下輸入對輸出的貢獻以及其它有用的量。