必需的

Both lixiviation and heating digestion methods were used in determination of potassiumand calciumin alfalfa.

牧草在畜牧业发展中起着非常重要的作用，而作为牧草生长发育所必需的矿质元素钾和钙，是则保持牧草营养价值的重要成分[1，2]。

This arrangement was applied to the detection of water soluble vitamin K (menadione sodium bisulfite, MSB) to avoid the complex and time consuming derivatization procedure required for the UV and fluorescence detectors.

将其用于检测药物中的维生素K3，克服了紫外检测法和荧光检测法所必需的柱后衍生化反应及电化学还原检测中溶解氧、金属离子的干扰。

Separation of the prosencephalon is induced by the prenotochordal mesoderm, which is needed for normal deelopment of the midline facial structures.

前脑的分裂是由前脊索中胚叶所诱发的，这是颜面中线结构正常发育所必需的。

The selenium is one kind of microelements in the earth's crust, it is one of 14 kinds necessary microelement for human body.

硒是地壳中的一种微量元素，它是目前已知的14种人体必需的微量元素之一。

Zinc is the microelement necessary for human body, which exists in human body in the manner of protein and metal enzyme, performing various important biological functions.

锌是人体必需的微量元素，锌以蛋白质和金属酶的形式存在于人体中，履行着各种重要的生物功能。

In preious studies, Millar and colleagues hae shown that this pathway is essential for initiating the formation of hair follicles and mammary glands in mice.

原来的研究， Millar和同事已经揭示这条通路对于小鼠毛囊和乳腺最初的形成是必需的。

It is concluded that the N terminal amino acids is essential for the mucin degrading activity of enhancin.

这一结果表明，增强蛋白的N端对其降解围食膜粘蛋白的功能是必需的

In January 2007, buy when the group during one word is popular with each passing day, fence net replaced the group that do not have care to buy a network, turn and be about to register for home marry, the Neozoic family consumer that enters matrimony offers the new home that builds new family place to need to decorate, marry prepare, a series of relevant domesticity such as the car consume a service.

在2007年1月，当团购一词日渐流行之际，篱笆网替代了无忧团购网，转而为国内即将登记结婚，步入婚姻生活的新生代家庭消费者提供建立新家庭所必需的新房装修、结婚筹备、汽车等相关的一系列家庭生活消费服务。

As far as the complicated nitrobenzene compounds production wastewater is concerned, to adopt pretreatment process is essential and feasible.

概括如下： 1。研究结果表明：对成分复杂的硝基苯类生产废水，首先采用前处理工艺是必需的，也是可行的。

Eric Noll, executive vice president of Nasdaq OMX, said:"Despite our best efforts, the increasingly competitive nature of the MTF space in Europe has meant that the growth of the business hasn't reached levels necessary for us to realise our stated objectives."

纳斯达克OMX执行副总裁埃里克·诺尔表示："尽管我们竭尽所能，但欧洲多边交易设施市场竞争日益激烈的特性意味着，该业务的增长没有达到使我们实现既定目标所必需的水平。"

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。