本底

We addressed the systematic errors originated from the synchronized photoelectron beams, which desorbs quite a few gaseous molecules adsorbed on the vacuum chamber walls, in mesuring the base pressure of the large storage ring of Beijing electron positron collider.

当BEPCⅡ储存环的束流突然丢失时，真空计和离子泵的压力测量值都先有一个瞬时的减小，之后才逐渐降低到本底压力。

The transcription of hsp70 was detected in the major tissues of hepatopancreas, muscles, eyestalks under both normal and heat shocked conditions .The mRNA level was increased after the animals were heat shocked in the 3 tissues.

因此本文所克隆的中国对虾hsp70是一种无明显组织特异性的组成性表达的基因，其转录表达能被某些应激进一步诱导，使转录水平在本底基础上提高。

The geologists have attached much importance to the particularity of ReOs isotopic system and its application is getting popular. The author sums up and compares several kinds of sample digestion methods for ReOs isotope analysis (NiS fire assay, Carius tube digestion, high pressure asher, leaching, and water disposing), the procedures of separating Os ( conventional distillation, liquid Br2 and CCl4 or CHCl3 extraction, rapid extraction with low blank, minitype distillation) and purifying Os, improved mass spectrometry measurement of Os isotope and its application progress in the earth science research brought along the improved measuring method.

总结和对比了近年来ReOs同位素分析中样品分解的不同方法（NiS火试金法、Carius管溶样法、高压灰化消解法、浸提法、水样处理法）、Os的分离（常规蒸馏、液溴和CCl4提取、快速低本底提取、小型蒸馏）与纯化流程、Os同位素比值质谱测定法（NTIMS、ICPMS、微区原位分析）及随测定方法的改进ReOs同位素体系在地球科学研究中的应用进展。

Shell gather candy in absorb while getting rid of drinking water harmful substancing , K+、Ca2+、Na+、Mg2+、SO42-、Cl-、HCO-3 ,etc. of adsorbed water, do not influence this density of bottom of the natural water body , and restrain funguses , sterilization function , it is the ideal absorbent drinks aqueous cleaning.

壳聚糖在吸附去除饮用水中有害物质的同时，不吸附水中的K+、Ca2+、Na+、Mg2+、SO42-、Cl-、HCO3-等离子，不天然水体的本底浓度，且有抑菌、杀菌作用，是饮用水净化的理想吸附剂。

Combining with its function demands, the eco-environmental water demand of Dongchange lake is divided into four parts: water demand of eco-environment inprovement, background water demand, landscape water demand of greenbelt and entertainment water demand of lake littoral zone.

以东昌湖为例，结合其功能要求，将其生态环境需水量划分为以下四个组分：水体生态环境改善需水量、水体本底需水量、湖滨带绿地景观需水量和湖滨带娱乐需水量。

The results showed after black radiation background was deducted,two radiation peaks of 2～2.5 μm were present in infrared radiation spectrum of the acupoints.

结果发现扣除黑体辐射本底后，穴位红外辐射光谱上出现 2～ 2 。5 μm和 15 μm两个辐射峰。

Employing a general Monte Carlo code MCNP, the following Monte Carlo calculations which are important in the design of PAN shufflers were done:(1) optimization of moderators;(2) detection efficiency variation with the position of a neutron source;(3) multiplication effects and self-shielding effects;(4) isotopic effects;(5) shielding properties of the storage chamber and the assay chamber;(6) the relation between 〓Cf source strength and background neutron count rates.

文章详细讨论了无源方式下中子总计数分析和符合计数分析以及有源方式下缓发中子分析的基本原理，在此基础上，运用通用蒙特卡罗程序MCNP计算了桶装废物分类装置研制过程中所关心的一系列问题：慢化体的优化设计、探测效率随中子源位置的变化情况、增殖和自屏蔽效应、同位素效应、贮存室和测量室对〓Cf源的屏蔽能力、〓Cf源强度与本底计数率的关系，等。

In order to solve the problem, we set up a method to simulate experimental spectra for medium-heavy nuclides in AMS measurements.

在AMS测量过程中的一个关键问题是排除同位素和同量异位素及其它本底的干扰。

The dependence of the frequency range on structural paramerter (crystal lattice shape, the ratio of the rod radius and the lattice constant) and electromagnetic parameter (the dielectric constants of the rods and of the background, incident electromagnetic waves with different polarization) were investigated.

同时，分析了AANR频率范围随着结构参量(晶格类型、介质棒半径与晶格周期的比值)和电磁参量(介质柱介电常量、本底介电常量、入射电磁波偏振方向)变化的行为。

Objective To determine the distribution and fluctuation of vectors at Shunyi Olympic Rowing-Canoeing park of Beijing, providing background data for vector control in the area.

目的 掌握北京市顺义奥林匹克水上公园病媒生物分布及消长基本情况，为该区域病媒生物防治工作提供本底数据。

And Pharaoh spoke to Joseph, saying, Your father and your brothers have come to you.

47：5 法老对约瑟说，你父亲和你弟兄们到你这里来了。

Additionally, the approximate flattening of surface strip using lines linking midpoints on perpendicular lines between geodesic curves and the unconditional extreme value method are discussed.

提出了用测地线方程、曲面上两点间短程线来计算膜结构曲面测地线的方法，同时，采用测地线间垂线的中点连线和用无约束极值法进行空间条状曲面近似展开的分析。