双交换

cm，室温下4800Oe外场作用下的磁电阻变化率为2.25%，对此用双交换作用机制定性地加以了解释。

Double exchange mechanism is used to qualitatively account for the magnetoresistance effect .

在T>TC区域，电阻率、磁电阻都随温度的升高而迅速下降，样品在高温（TC附近及T>TC区域）的这一行为可用双交换（DE）模型与非磁无序来说明。

This behaviors can be explained by double exchange ( DE ) model and nonmagnetic randomness .

这些结果归因于Zn掺杂引起的双交换作用、磁稀释作用和晶格效应。

The results are attributed to double exchange interaction , magnetic dilution and lattice effects arising from Zn doping .

由于Fe3+取代Mn粒子，致使双交换作用通道被打破，化合物的电阻率随x的增加而迅速增加。

The resistivity increased obviously with x because the double exchange interaction channel was broken by Fe 3 + addition .

最后，我们从双交换机制和可变程跃迁模型出发，对体系的输运特性与晶体结构随Co掺杂浓度变化之间的关联进行了初步讨论。

The correlation between transport properties , crystal structure and Co doping concentration were also discussed based on the double exchange mechanism and the variable-range-hopping model .

非双交换作用巨磁电阻材料FeCr（2-x）GaxS4的输运行为

Transport behavior of non-double-exchange CMR material fecr_ ( 2-x ) ga_xs_4

用锰氧化物晶场和双交换作用的竞争解释了其温度Tp以下的金属特性。

Using the competing between manganites crystal field and double exchange interaction explains the metal property at room temperature .

实验结果表明Ga掺杂破坏了双交换作用，使电阻率上升而磁有序转变推移到低温。

The experimental results suggest that Ga doping destory the double exchange interaction so that the resistivity rises and the Curie temperature decreases to lower temperature .

掺Bi可以使低温下的低场磁电阻得到显著增强，但并不改变与双交换作用有关的本征磁电阻；

Doping Bi can evidently improve the low field magnetoresistance at low temperature , while the intrinsic magnetoresistance related to the double exchange interaction may not be changed .

在掺杂量0.3≤x≤0.5的区域范围内，随着x的增加，双交换作用逐渐增强，有利于低温下铁磁态的形成。

In the doping range of 0.3 ≤ x ≤ 0.5 , with the increasing of x , the doping of La 3 + cation favors the formation of ferromagnetic state which is due to the strengthen of the double exchange interaction .

实验结果表明，是双交换作用和小极化子效应的共同作用决定了CMR效应的特性。

The experimental evidences show that both actions of double exchange interaction and small polarons are responsible for the variation of the CMR effect .

磁测量的结果表明纳米线的铁磁转变温度比相应块材的有所提高，主要是因为纳米线的eg电子带宽增加使得双交换作用增强所致。

The result of magnetic measurement indicates that the nanowires have an enhanced TC compared with that of the corresponding bulk compound . This is related to the increased bandwidth W which enhances the double exchange interaction and favors the delocalization of eg electrons .

认为很大的磁电阻效应与用离子半径小的Y部分替代离子半径大的La有关，它会破坏双交换作用，从而导致Jahn-Teller效应。

It is suggested that it may be related to the partial substitution of La ~ ( 3 + ) cation with smaller Y ~ ( 3 + ), which may destroy the double exchange interaction of ( Mn O Mn ,) giving rise to Jahn-Teller effect .

目前主要存在两种观点：一种为由载流子诱导的铁磁交换耦合，如RKKY、双交换作用。另一种是与样品中的缺陷有关的束缚磁极化子模型。

There are currently two theories to explain the observed ferromagnetism : One is the ferromagnetic exchange coupling mediated by carriers , such as RKKY and double exchange models ; the other is the bound magnetic polaron ( BMP ) model , which is related to the defects in materials .

从结构和磁性两个方面，证实了双交换模型在解释锰氧化物的铁磁金属性是合理的。

The above results support the double exchange model in manganite .

2维双交换模型的金属-绝缘体转变

Metal-insulator transition of two-dimensional double exchange model

在此基础上，对双交换四分子的分析和着丝粒作图进行了详细地讨论。

Based on this , double exchange of tetrads and centromere mapping are analysed and discussed in detail .

第一步单交换和第二步双交换的频率分别是05%～07%和2%。

The first single-crossover and the second double-crossover frequencies were approximately 0.5 % ~ 0.7 % and 2 % , respectively .

Cr3+具有和Mn4+相同的电子组态，因此Cr3+与Mn3+间是否具有双交换作用是一个未解决的问题。

Cr3 + has the same electronic configuration as Mn4 + , so whether or not DE coupling between them remains an open question .

这一方法为研究钙钛矿锰氧化物中的双交换理论提供了一个全新的思路，也能为寻求室温磁电阻材料提供参考。

Such a process presents a new way to study DE in manganites , which would be beneficial to search out the room temperature magnetoresistance materials also .

认真研究了2维双交换模型的局域化性质，利用有限尺寸标度方法和转移矩阵技术计算了系统的局域化长度和电导。

The localization properties of two-dimensional double exchange model was studied carefully . And the localization length and conduction were calculated by finite-size scaling method and transfer-matrix technique .

重组质粒反复转化冰岛硫化叶菌，得到质粒整合到宿主染色体上的单交换菌株，但没有获得反螺旋酶基因缺失的双交换转化子。

Based on the homologous recombination , the plasmid pRG of reverse gyrase gene knock-out was constructed and transformed into the Sulfolobus islandicus and the single crossover mutant was isolated .

目前使用的基因突变方法，如自然转化，接合转移以及自杀质粒电转化的转化效率和发生同源重组双交换的效率比较低下，所以一套高效的突变系统的建立是非常必要的。

The current methods of mutation including natural transformation , conjugation and electroporation using suicide plasmid are defective in the efficiency of transforming and double exchange of homologous recombination . So it is necessary to establish a set of effective mutation system .

π核双电荷交换反应的自旋效应和πN振幅离壳修正

Spin effect and π - n off shell amplitude correction on π - nucleus double charge exchange reaction

本文利用50MeVπ-核双电荷交换反应（DCX），研究了原子核内夸克自由度存在的问题。

The quark degrees of freedom in nuclei has been studied by using 50 MeV double charge exchange reaction .

研究原子－双原子交换过程的BKLT积分方程的解

The solution of bklt integral equation for atom-diatom exchange processes

本文提供求解非相似双电荷交换跃迁（DCX）非线性积分问题的一种分析模型和分解方法。此分解方法提供一个有效的计算程序，用于求解能源研究中一（大）类非线性多重积分问题。

An analytical model and a decomposition method are proposed for solving the nonlinear integration problem of Double Charge Exchange transition ( DCX ) .

π核双电荷交换反应与核结构

π - nuclear double charge exchange reaction and nuclear structure

二级π-核光学位及双电荷交换反应

Second order pion-nucleus optical potential and double charge exchange reaction

π核双电荷交换四极跃迁

Quadrupole transition with π - nucleus double charge exchange