查询词典 necessary condition

Economic growth may be necessary but is not a sufficient condition for the development of modern freedom.

经济增长可能是现代自由发展的一个必要而不充分的条件。

Low interest rates are a necessary but not sufficient condition.

低利率是一个必要条件，但不是充分条件。

The telemetry sub is the core of organization and management of the system,which provides necessary support of software and hardware for data acquisition, processing andtransmission;the ultrasonic imaging televiewer visually presents the condition of interwall ofcasing and the borehole wall;the acoustic caliper quickly and quantitatively detects the status ofinterwall of casing and borehole wall;the azimuth logging tool provides the casing damagelocation demanded by ultrasonic imaging televiewer and acoustic caliper.

遥测短接为该系统的组织管理核心，为各功能短接提供数据采集、处理及传输等所必需的软硬件支持；超声成像仪可直观显示套管内壁或井壁的自然状况，声波井径仪可快速定量检测套管内壁或井壁的状况；方位仪为超声成像仪及声波井径仪提供所需的套损方位。

Based on the theory of B spline,this paper discusses the sufficient and necessary conditions of G 1 continuity between two patches of bi cubic tensor product non uniform B spline surfaces in a special type,and gives a kind of sufficient condition of G 1 continuity so as to satisfy the need of application.

依据有关B样条理论，研究了一种特定类型的双三次张量积非均匀B样条曲面间G1光滑拼接的充要条件，且给出了此种类型的两张双三次张量积非均匀B样条曲面间G1光滑拼接的一个充分条件，以满足实际应用的需

And we obtain a necessary and sufficient condition for a trivial extension to be semicommutative ring.

得到平凡扩张是半交换环的一个充要条件。

The results showed that there existed variation among eucalypt families in wood physical-mechanical properties and wood chemistry. There were significant differences among E.pellita families、E.grandis families and E.urophylla譋.grandis clones in wood colors as well as between Strains and within trees.The variation of the surface wetability of wood between E.grandis families and E.urophylla譋.grandis clones were significant.Even in the same families level or clones level,there still existed the same regulation. The degree of collapse of eucalypt had a large relation in the amount of tylosis in vessel and vestured pits on the cell wall of vessel. The more rich tylosis and vestured pits in vessels,the more probability to occur collapse for eucalypt.The biggest moment collapse was probably the critical point of the drying degrade.During the fomulation of drying technology,it is necessary to adopt moderate condition to make the vessels which had formed the biggest moment collapse at the biggest moment collapse resume,especially to prevent the permanent set.At the normal temperature level,the main factors which influenced residual collapse were the contents of ray parenchyma and axial parenchyma .Nearly all the cells joined the course of forming the moment collapse and biggest moment collapse.Interval drying was fit for eucalypt plantation which was easier to make collapse.

研究表明：桉树不同家系间木材物理力学性质和化学组成存在差异；粗皮桉家系间、巨桉家系间、尾巨桉无性系间材色存在显著差异，株间、株内木材材色存在变异；桉树木材表面润湿性在巨桉家系间、尾巨桉无性系间存在着显著差异，在同一家系或同一无性系中，株间和株内也存在着相同的变化规律；桉材皱缩程度与其导管中侵填体的多少和导管壁上纹孔具有的附物多少密切相关，侵填体含物越丰富，纹孔附物越多，桉材越容易皱缩；最大瞬间皱缩是能产生更大干燥降等的临界点，在制定干燥工艺时，必须在最大瞬间皱缩发生时，采用温和条件，使已产生最大瞬间皱缩的细胞尽可能多的恢复，尤其不能使其产生永久变定；在常温条件下，影响残余皱缩的主要因子是射线薄壁细胞和轴向薄壁细胞含量；而对于瞬间皱缩和最大瞬间皱缩，几乎所有细胞都参与它们的形成过程；对于易皱缩的桉树木材，间歇干燥是最有前途的干燥方法。

A necessary and sufficient condition for the unbiasedness of Balanced LS Estimation is gained, and for the given L, t can be chosen to make the MSEM of the Balanced LS Estimation less than that of OLS Estimation.

给出了平衡LS估计为无偏估计的充分必要条件，对于给定的L，适当地选择参数t可使平衡LS估计的均方误差矩阵小于OLS估计的均方误差矩阵。

A method is proposed to solve the identical self-synchronization of undecomposable chaotic system based on He and Vaidya's necessary and sufficient condition for synchronization.

基於He和Vaidya的同步充分必要条件，提出了一个解决未拆分混沌系统恒等自同步的方法。

In addition, the necessary and sufficient condition of the constraint system for a unique solution is also provided.

该方法的特点在于，无须知道矩形的任何几何信息，也不涉及图像匹配问题，而且所有计算方法均是线性的。

Therefore, it is necessary to explain the usage condition of the theorem of uniqueness of solution of elasticity.

为此，需要对弹性力学解的唯一性定理的适用条件适当加以说明。

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％。