查询词典 h.a.

TRY this next time you are strolling on a cliff. Toss a rock (the size of a blood orange is good) over the edge and begin to count. It falls at the speed of a tumbling human so will reach 200km per hour after nine seconds, roughly the acceleration of a supercar.

下次你在悬崖边溜达时试试朝悬崖边扔一块石头并开始计时，它会像一个坠落的人一样9秒后达到200km/h，大体像一辆跑车的加速能力。

In the reaction of a-stannyl radical addition to carbonyl to form six-membered ring, we constructed a sulfonyl group at the a position of the formyl group to inhibit 1,5-H shift in order to increase the cyclization product yield. We obtained 41 % yield of the cyclization product in this system.

在 a-锡基自由基加成到醛基形成六员环的系统中，我们在醛基的 a 位上加入碸基来抑制 1，5-氢转移并提升环合产物之产率，在这个系统中，我们得到了 41 %的环合产物。

A 』i nal h.a m:am/（a'ina-l-hammam?, a ee null hhum mum?）note: these were snagged off of Ajeeb.com's Web translator, with SAMPA and spelling guide renderings a best-guess only.Note on SAMPA: a comma after a fricative indicates that it is apical rather than laminal.

注意这里使用的是古典阿拉伯语；既然有很多普通的片语，但是他们在当地不同的方言中会有不同，这意味著很多阿拉伯人，甚至是受到教育的人，都会对这些共同片语有不同的理解。

A 'i nal h.a m:am/（a'ina-l-hammam?, a ee null hhum mum?）note: these were snagged off of Ajeeb.com's Web translator, with SAMPA and spelling guide renderings a best-guess only.Note on SAMPA: a comma after a fricative indicates that it is apical rather than laminal.

注意这里使用的是古典阿拉伯语；既然有很多普通的词组，但是他们在当地不同的方言中会有不同，这意味著很多阿拉伯人，甚至是受到教育的人，都会对这些共同词组有不同的理解。

P a cific puffin h a ving a l a rge yellow plume over e a ch eye.

北太平洋的海鹦，每只眼睛上方有一簇黄色的羽毛。

A sked the sweet, silvery voice of Mercédès;"two o'clock h a s just struck, a nd you know we a re expected in a quarter of a n hour."

美塞苔丝那银铃般的声音问道，"两点钟已经过了，你知道我们说好的在一刻钟之内到维丽大酒家的。"

The matrix extension problem is, under some constrained conditions, constructing a matrix A with a given matrix A_0 as its submatrix.

矩阵扩充问题是在某种约束条件下构造矩阵A，使得矩阵A的一个子矩阵为A_0.1979年，H。

In many practice problems such as to know the resonnance frequency of a structure and to know the critical value for the stability of a dynamical system,often need to compute the eigenvalues of a symmetric matrix. The chief method to compute the eigenvalues of a symmetric matrix is first to transformate the matrix to a symmetric tridiagonal matrix similarly and orthogonally, then to use the QR method with shift to the symmetric tridiagonal matrix.

很多实际问题，如求结构振动的固有频率，动力系统稳定性的临界值等常常归结为计算对称矩阵的特征值，而首选的计算方法是先把该矩阵正交相似变换成一个对称三对角矩阵，再对这个对称三对角矩阵用带位移的QR方法。1968年J.H。

The factors A and the rate constants are given at temperature range of 200-1200 K.The results in-dicate that the loss of aβ-hydrogen from 2-hydroxyethyl radical to yield vinyl alcohol and that a 1,3-hydrogen shift to form ethoxy radical have close A factors and rate constants.

用量子化学结果和Eyring过渡态理论计算了200－1200K温度范围内，标题反应的A因子和速度常数，结果表明，2－羟乙基脱去β－H生成乙烯醇与其经［1，3］重排生成乙氧基有相近的A因子和速度常数，且常温下速度较慢，反应难以进行。

Novozym 435 was used for the synthesis of vitamin A plamitate. The influences of solvent, the molar ratio of substrates, the reaction temperature and time, and the water concentration were optimized and the best result was obtained by interesterification from 0.200 g vitamin A acetate and 0.468 g palmitic acid, at 30℃, in 10 mL hexane, containing 0% of water, with 10% of lipase(mass ratio, immobilized lipase to vitamin A plamitate). In these conditions, 75% of vitamin A acetate was converted into vitamin A plamitate. The immobilized lipase was reused about 6 batches.

对催化合成维生素A棕榈酸酯反应的脂肪酶和反应介质比较，同时对影响合成维生素A棕榈酸酯反应的因素（温度、初始水含量、底物摩尔比、反应时间和酶量等）进行了探讨，优化了反应条件：在10 mL不含水分的正己烷中，0.200 g 维生素A醋酸酯和0.468 g棕榈酸在酶量为10％（指固定化酶与维生素A醋酸酯的质量比）的固定化脂肪酶催化下，在 30℃、190 r/min下反应6 h，转化率可以达到75%，固定化酶可连续使用6次以上。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。