一阶

A new method based on the Fourier-Bessel series is proposed to calculate the higher-order harmonic components of a nonlinear ultrasound field in absorbing medium and an analytical solution of a series form is obtained. A closed analytical solution of the higher-order harmonics in the zeroth-order Bessel ultrasound field and the focused Gaussian ultrasound field is deduced to study the field property, especially the near-field property.

提出了一种基于Fourier-Bessel级数的新方法，用于计算吸收媒质中非线性超声场的高次谐波分量，得到其级数形式的解析解，由此推导出吸收媒质中零阶Bessel超声场、Gauss聚焦超声场高次谐波的封闭解析解，进而对其声场特性尤其是近场特性进行了研究。

In this paper an innovative method for machining sculptured surfaces is presented. By using a disc cutter with a concave end instead of traditional ball-ended or drum-shaped tools, and adjusting the cut- ted axis to swing relative to the component being machined under some special rules, the envelope formed by the trace of the tool-nose may have the same derivative up to the third order as the required theoretical surface.

本文提出了一种加工自由曲面的新方法，即采用中凹的盘形铣刀取代传统的球头或鼓形铣刀，在每一行程中让刀具轴线相对于工件按特定的规律摆动，使得在垂直于进给方向的法截面中，由刀尖轨迹形成的包络面与理论曲面的法截线具有相同的1～3阶导数，从而在保持精度不变的前提下，使实际行程次数得以大幅度的减少。

As a result of the relative difference in their velocities, polarized rays vibrating in planes of principal stresses S 1 and S 2 will emerge with a relative phase shift and produce color interference fringes or multicolored bands.

由于这一相对差，在其速度，偏振射线振动，在飞机的主应力s 一和S 2将会出现一个相对的相移，并产生彩色干涉条纹或彩色阶。

Principal component analysis is a successful feature detection method for pattern recognition. It is the optimal dimension compression technique based on second-order information in the sense of mean-square error.

主分量分析是一种在众多生物特征识别中获得成功应用的特征提取技术，是一种基于二阶统计的在最小均方误差意义上的最优维数据压缩技术，它所提取的各特征分量之间是互不相关的。

Considering nodal pressure as the evaluating indicator, functional reliability indexes of the nodes were calculated by the mean-first-order-second-moment method which was originally developed for structural reliability analysis.

在进行供水管网的抗震功能可靠度分析时，借鉴结构可靠度的分析方法，以节点水压为评价指标，采用均值一次二阶矩方法计算管网各节点的功能可靠度，该方法通过一次水力分析即可给出震后低压供水和渗漏状态下管网各节点的可靠性指标，较之前发展的随机模拟方法大为简化且概念清晰。

Considering nodal pressure as the evaluating indicator, functional reliability indexes of the nodes were calculated by the mean-first-order-second-moment method which was originally developed for structural reliability analysis.

在进行供水管网的抗震功能可靠度分析时，借鉴结构可靠度的分析方法，以节点水压为评价指标，采用均值一活动板房次二阶矩方法计算管网各节点的功能可靠度，该方法通过一次水力分析即可给出震后低压供水和渗漏状态下管网各节点的可靠性指标，较之前发展的随机模拟方法大为简化且概念清晰。

Ten years ago, Shirō was caught in a massive fire hazard that incinerated his parents and consumed a large portion of the city; as he was dying, an enigmatic man discovers and treats him.

他们是由圣杯选择的七位英灵，被分为七个职阶，以使魔的身份被召唤出来。能获得圣杯的只有一组，这7组人马为了成为最后的那一组而互相残杀。

In the analysis of reliability of system under random excitations, the spectral moment s of response are very important parameters.

提出了一种新的计算弹性-粘弹性复合结构随机响应的各阶谱矩的计算方法，它是一种时域复模态分析方法。

A classical example of this is the Turgot map of 18th century Paris, an engraving produced in twenty sections.

应用视觉化的工作最好向一章印好的大型图表，大到可以涵盖所有的细节、组织，让人一看就可以了解高阶的结构。

When 〓 is the family of bipartite graphs,the 〓 capacityand the 〓 valency of a graph G are referred to as the biparticitydenoted by β(Gand the bivalencydenoted by 〓(Gof G respectively;when 〓 is the family ofgraphs whose components are complete bipartite graphs,the 〓 capacity and the〓 valency of a graph G are referred to as the complete biparticitydenoted byc(Gand the complete bipartite valencydenoted by 〓(Gof G respectively;andwhen 〓 is the family of star forests,the 〓 capacity and the 〓 valency of a graphG are referred to as the star arboricitydenoted by st(Gand the star valency ofG(denoted by 〓)respectively.

以v记图G的完全二部分解中顶点υ所关联的π中完全二部图的个数，记〓这里π取遍G的所有完全二部分解。我们称υ为G的完全二部次。对一般的图，当图的阶数充分大时，P。〓和L.Pyber给出了υ的一个上界，即，〓。F.R.K.Chung等人及Z.Tuza的结果说明这一上界是不可改进的。对υ的具体值，即使是对某些特殊的图类，结果也知之甚少。P.C.Fishburn和P.L.Hammer给出了一个相关的结果：当n≤16时，〓，（在υ的定义中，以完全二部覆盖替代完全二部分解，即得〓。同时他们提出了下述公开问题。问题1。〓=？

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。