查询词典 stem

There are two hypotheses to explain the origin of liver cancer stem cells: the dedifferentiation of mature hepatocytes and the maturation arrest of liver stem cells.

通过实验，研究人员对于肝癌干细胞的来源提出了两个假说：成熟肝细胞的去分化与肝干细胞的"成熟受阻"。

It turned out that hematopoietic stem cells be immortalized by constitutive Notch1 and Delta has the function as the mitogenic regulators of hematopoietic stem cells.

研究人员将活化形式Notch受体导入造血干细胞，使其获得了细胞因子依赖性的"永生"；另外，Notch的配体Delta、Jagged具有类有丝分裂因子作用，可保持造血干细胞的自我更新能力，促进其体外增殖。

According to lift method and Hooke's law and applying differential and integral calculus theory, calculated equation for free point of these string is reduced respectively,and considering influence of collar and adding power from stem to it, corrected coefficient to drill stem is determined.

对在井中被卡的单一管柱和组合管柱分别进行了受力分析；采用提升法，依据虎克定律，应用微积分理论，分别推导出了单一管柱和组合管柱的卡点计算公式；并且考虑了管柱接箍、管柱加厚对其影响，确定了管柱修正系数。

BACKGROUND: Effective proliferation in vitro of neural stem cells and directional induction and differentiation of dopaminergic neurons play a key role in neural stem cell transplantation for treatment of degeneration of the nervous system and repair of injured nervous system.

背景：在神经干细胞移植治疗神经系统退行性变及修复神经系统功能损伤过程中，有效的神经干细胞体外增殖与多巴胺能神经元的定向诱导分化尤为关键。

Other features include a safe-block ball seat and blow-out-proof stem with double stem seals that provide complete operator protection and maintenance-free ...

其他功能还包括一个安全座椅和块球击出，双干密封，提供完整的操作和维修保护无防干。。。

Anti-static design Blow-out proof stem Pressure balance device on the ball Double stem packing and two-pieces shrapnel device Clearance device on the body

阀杆防爆出装置。◇钢球上设计有压力平衡孔。◇双层阀杆填料与两片蝶性弹片装置。◇阀体上设计清洁阀腔装置。

In this paper, ADAMS and ANSYS software are used to build the model of drill stem and dynamically simulate the distortion of drill stem in vertical well.

本文利用ADAMS软件和ANSYS软件，建立了钻柱模型，动态模拟了垂直井眼中钻柱的受力变形，直观准确地再现了钻柱与套管壁接触的全过程。

Considering the complex influence factors for the failure of drill stem,an analytic model for failure of drill stem based on support vector machine and cluster analysis theory was established.

针对钻具失效影响因素比较复杂的问题，建立了基于支持向量机和聚类分析理论的钻具失效原因分析模型。

In order to prevent abrasion and extend the service life, people deal with all kinds of researches. Now, people use a new method of preventing drill stem abrasion －Install non-rotating protector in the part near drill stem tie-in to solve this problem effectively.

为防止钻柱磨损和延长钻柱的使用寿命，人们从事了各种各样的研究工作，目前，工程上采用了一种新型的防磨方法——在靠近钻柱接头的部位，安装非旋转防磨减断保护套，有效地解决了这个问题。

This method displays the whole process of the contact between drill stem and well wall, and gives contact points and contact forces. It provides a reliable and practical aidlifetime of the drill stem. The method presented in this paper may also be adapand extended reach well drilling.

为实钻时，防止钻柱磨损和对钻柱寿命的预测提供了依据，对钻柱的结构设计以及钻柱力学的研究具有一定指导意义，本方法适用性强也可应用于定向井、大位移井等同类问题的研究。

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％。