中外场

In studying the linear response of the dressed quark propagator in the presence of the variable external field, we derive a general expression for the vacuum susceptibility, based on the two-point external field formula in the Quantum Chromodynamical sum rule. The expressions we have derived for the calculation of vacuum susceptibility are model independent. Then we use the expressions to calculate the renormalised axial vector, vector and tensor vacuum susceptibilities.

接下来在研究夸克传播子在外场中的线性响应时，我们利用QCD求和规则两点外场公式推导出了一般的计算真空磁化率的公式（以变化的轴矢量外场为例），我们这里推导出的真空磁化率的计算公式是模型无关的。

Center fielder Brad Wilkerson admits, though, that all those close games have started to affect the team.

不过，中外场手布拉德·威尔克森承认这些比分接近的比赛已经开始影响球队的状态。

The main reason is that the condition ismore complicated in open field,and measuring result is much more easily influenced bysome kinds of clutters,like atmosphere attenuation,cloud or fog,the fluctuating of scaleobject and ground clutter and so on.So these factors should be taken into account inpractical measuring,and make some amending processing.

主要原因是外场中情况复杂，测量结果受各种杂波影响较大，如大气衰减、云或雾、定标金属球的波动、地面杂波等，因此在实际测量中应考虑这些因素，并做出相应的修正处理。

The reasons of our choice are:(1) the coupling of the electromagnetic field with the matter is universal and there is already some experiences with such a kind of field in the literature;(2) the pion is the lightest hadron and its interaction with other fields are known to some extent. The pion fields have been treated as external fields but the discussion is not comprehensive in the literature.

我们选取这样的外场的理由如下：(1)电磁场与物质相互作用的耦合常数是普适的，而且文献中已经有把电磁场当作外场来处理的经验；(2)π介子是最轻的强子，它与其它场的相互作用人们已经有所了解，文献中也有把π介子场当作外场来处理的例子，但讨论还不够深入。

The influence of the electric field on the properties of the bound magnetopolaron in an infinite-depth GaAs semiconductor quantum well is investigated using the linear-combination operator and the unitary transformation method. The relationships between the polaron's ground state energy and the Coulomb bound potential, electric field, magnetic field, and well-width are derived and discussed.

研究了在外加电场作用下无限深GaAs半导体量子阱中束缚磁极化子的性质，采用线性组合算符及幺正变换方法导出了量子阱中弱耦合束缚磁极化子的基态能量与阱宽、电场强度、磁感应强度、库仑束缚势的变化关系，同时讨论了振动频率和库仑束缚势、外场之间的变化关系。

The influences of the external magnetic field on the properties of the excited state of the polaron in a parabolic quantum dot are studied by using the linear combination operator and the unitary transformation method, the relation of the first internal excited state energy E1, excited energy △E and the resonance frequency ω of both the strong-and weak-coupling polaron with the effective confinement length l0 of the quantum dot, the electron-phonon coupling strength α and external magnetic field B are derived.

采用线性组合算符和幺正变换方法研究了外场对抛物量子点中极化子的激发态性质的影响，导出了强、弱耦合情况下极化子的第一内部激发态能量E1、激发能量△E、共振频率ω与量子点的有效受限长度l0、电子－声子耦合强度α以及外场B的关系。

The mian works are as follows:(1)By coprecipitation technique and coprecipitation- gel technique the nano zirconia powder was produced, factors affecting the properties of nano zirconia powder such as pH and the content of stabilizator are analyzed;(2)By the new pressless sintering process, the nano zirconia ceramic was produced, factors which can affecting the properties of nano zirconia sinter body such as moulding press and the sinter temperature are analyzed;(3)By the microtherm pressless sintering process, the nano copper added functional zirconia ceramic composite was produced, microscopic dimensionality and electric properties of such sinter body and the factors affecting such sinter body are analyzed;(4)By the self-invented "external albumen coating" technique the zirconia powder was successfully coated by carbon in the corresponding sinter body, which can help solve the traditional aggregation problem to some degree;(5)Based on analyze the characteristics in the nano powder sinter process, the "three-ball sinter model" was proposed, for the relationship between the relative density and porosity of sinter body, by mathematical fitting, such model was successfully verified.

本研究比较系统地研究了纳米氧化锆陶瓷的合成与成型机理，特别是讨论了纳米氧化锆陶瓷的稳定性，为防止纳米颗粒在外场作用下的团聚和长大提供了理论基础和实验数据，具体工作有以下几方面：(1)采用共沉淀法和共沉淀-凝胶法制备了纳米氧化锆粉体，并分析了pH值和稳定剂含量对粉体性能的影响；(2)采用新型无压烧结工艺制备了纳米氧化锆陶瓷，并分析了成型压力和烧结温度对烧结体性能的影响；(3)采用低温无压烧结工艺制备出添加纳米铜的功能性纳米氧化锆复合陶瓷，并分析了烧结体的微观尺度和电学性能的变化以及影响因素；(4)通过自创的&鸡蛋清外敷法&在真空镀膜台上对纳米氧化锆粉体进行包敷碳颗粒的表面处理，并采用真空烧结工艺制得相应烧结体，初步开始解决陶瓷烧结过程中团聚长大这一传统难题；(5)通过分析纳米颗粒在制备烧结体过程中的实际特点，提出了&三球烧结数学模型&，通过引入坯体相对密度和孔隙率的相对关系分析并通过自行编写的数学拟合软件，验证了这一数学模型。

Functions in a weak external field like the pion or electromagnetic field, which polarizes the otherwise-with-no-Lorentz-structure QCD vacuum, induces new condensates and affects the propagation of quarks and gluons in the vacuum.

外场的存在，将使原来没有 Lorentz 结构的 QCD 真空极化，诱导出一些新的凝聚量，另一方面外场的存在将改变夸克在真空中的传播行为，并且需要增加一些唯象参量。

Fair ball:A batted ball that first strikes the ground or leaves the playing field beyond first or third base within the foul lines or that is within the foul lines as it bounces past first or third base or that comes to rest or is touched by a fielder in front of first or third base within the foul lines.

&界内球：棒球比赛中落在内场边线内的击球，或先触到外场场内或经过第一或第三垒滚进外场场内的击球。&

Fair ball:A bat ted ball that first strikes the ground or leaves the playing field beyond first or third base within the foul lines or that is within the foul lines as it bounces past first or third base or that comes to rest or is touched by a fielder in front of first or third base within the foul lines.

&界内球：棒球比赛中落在内场边线内的击球，或先触到外场场内或经过第一或第三垒滚进外场场内的击球。&

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。