查询词典 be at a distance from

The general condition for athermalizing an optical system when the object surface is at finite or infinite distance is deduced in this paper, and the principle and design method of employing a diffractive optical element to athermalize and achromatize an optical system with normalized T-C chart are expanded.

推导了物面位于有限远和无限远时，实现热补偿的通用条件；并阐述了利用归化T-C 图设计消热差和消色差的红外光学系统的原理和方法。

The general condition for athermalzing an optical system when the object surface is at finite or infinite distance is deduced in this paper, and the principle and design method of employing a diffractive optical element to athermalize and achromatize an optical system with normalized T-C chart are expounded.

本文推导了物面位于有限和无限距离时实现光学补偿的通用条件，论述了利用归化T-C图设计热补偿和消色差红外光学系统的原理和设计方法，给出了8-12μm波段内、焦距123mm、相对口径F/2.5在20-60℃温度范围内的折衍混合红外光学系统的设计结果和理论评价结果，所述的设计方法可方便地推广到前视红外系统中。

What time and distance to memory is like acid to rock.

记忆就像岩石，时间和距离如酸质般将它侵蚀。

Time and distance erode it like acid does to the rock.

记忆就像岩石，时间和距离如酸质般将它侵蚀。

First, the speed of the reaction between mud acid and rock is very fast, the effective distance of acid is short, active acid can not reach deep formation.

首先，高温下常规土酸与地层矿物反应速度极快，酸液有效作用距离短，活性酸不能到达地层深部；其次，HF与铝硅酸盐的化学反应不是简单的一次反应，其副产物氟硅酸和氟铝化物还可与铝硅酸盐发生二次反应和三次反应，形成一系列不溶性的沉淀物，对储层造成严重伤害；第三，高温情况下酸液对井下管柱及工具腐蚀性很强，对缓蚀剂性能要求高。

Near distance acoustic fields are payed attention in intelligent acoustic mine and the measurement of tranquil targets' radiate field and acoustic feature monitor of targets in the haven , etc.

"智能"水雷声引信、目标低噪声辐射声场测量和港口目标声特性监测等场合均关注近程(2Km以内)声场。

The presented concept of "beam-distance acoustic image" and "beam-depth acoustic image" provide torpedo near field control and guide characteristics.

提出目标近场波束-深度和波束-距离二维声图象的概念，为鱼雷末制导阶段提供了目标近场回声二维特征。

The ability of long-distance searching goals of an acoustic homing torpedo can be improved greatly by using towed linear array , and the power of DOAs tracking of the torpedo is the key factor that influences the result in a war.

使用拖曳线列阵可以有效提高自导鱼雷远程搜索目标的能力，而能否精确跟踪目标方位将直接影响到鱼雷的实战效果。

In order to reduce calculation in the process of vertical scale identification of torpedo acoustic image,we present an improved decoherent multiple signal classification method based on quadrature complex sampling which suits to estimating the vertical highlights of submarine with the characteristics of near distance and coherent signals .

在鱼雷声成像垂直尺度识别中，根据潜艇垂直方向上目标亮点相距较近，且为相干信号源的特点，同时为了减小运算量而易于工程实现，提出了一种基于正交采样的高分辨DOA估计算法，即正交解相干MUSIC算法。

For the active acoustic fuze for a torpedo on the basis of the distance measurement done by using acoustic pulses, the echo of a randomly undulating wave is a main disturbance to recognize a surface ship.

摘 要：基于脉冲回声探测的主动声引信识别水面舰船，随机起伏的波浪回声干扰是限制其可识别水面舰船最小吃水的主要因素。

However it can often be frust ating for a child when people are unable to pronounce their name.

但它往往可以令人沮丧的一个孩子当人们无法断言他们的名字。

All these compounds were obtained from this genus for the first time. Compound, 4-cumylphenol, was a new nature product.

所有化合物均为首次从本属海藻中分离得到，其中4cumylphenol为新天然产物。