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In the context of massive(bi-)gravity,non-minimal matter couplings have been proposed.These couplings are special in the sense that they are free of the Boulware-Deser ghost below the strong coupling scale and can be used consistently as an effective field theory.Furthermore,they enrich the phenomenology of massive gravity.We consider these couplings in the framework of bimetric gravity and study the cosmological implications for background and linear tensor,vector,and scalar Previous works have investigated special branches of solutions.Here we perform a complete perturbation analysis for the general background equations of motion,completing previous analyses. 相似文献
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用热释光探测器对快堆堆外n,γ混合场进行了区分测量,结果表明:该方法可有效的检测出n,γ混合场的γ成分;为了更较精确地测量快堆n,γ混合场γ光子注量,提出了采用新配方的热释光探测器LiFTLD(6LiF,7LiF各占50%)与6LiFTLD成对使用的方法.考虑到LiFTLD对中子吸收剂量的响应存在LET效应,对LiF(Mg,Cu,P)TLD进行了中子响应的LET效应因子RLET的实验测定(RLET≈005),在此基础上,对6LiF 7LiFTLD的成对使用测量快中子堆的n,γ混合场中光子注量的方法进行了实验研究.实验结果表明,混合场中的中子在7LiF(Mg,Cu,P)中产生的热释光量(TL)占n,γ产生的总TL的81%—171%.实验结果表明该方法是行之有效的.为钝化中子谱的不确定性所致的影响,进一步提高γ光子注量测量结果的精度,提出了采用新配方的LiFTLD(6LiF,7LiF各占50%)与6LiFTLD成对使用测量快堆n,γ混合场γ光子注量的方法. 相似文献
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《普通高中数学课程标准(实验)》倡导自主探索、动手实践、合作交流、阅读自学等学习数学的方式,使学生的学习过程成为在教师引导下的“再创造”过程。学生的学习过程是学生依据自已的知识结构和数学活动经验,让知识在大脑中不断自然生长从而建构知识的过程。下面笔者通过《椭圆的标准方程》的教学谈谈自已的一点想法。 相似文献
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用气体放电法研究含氘金属异常现象时,发现有X射线产生.因此用吸收法、特征X射线法和NaI闪烁计数器测量了X射线能量,用7Li热释光片估测了X射线强度.吸收法测出的X射线平均能量为(26.9±2.2)keV和NaI闪烁计数器测出的(26.0±2.4)keV单能X射线在测量误差内相符. X rays were observed to create when the anomalous phenomenon in the metal loaded with deuterium studied by the gas-discharge method. Therefore the X-ray energy spectra were measured by the absorption method, the specific X-ray approach and the NaI scintillation counter, while X-ray intensity was estimated by using 7Li thermoluminescent foils. The X-ray average energy measured by the absorption method is 27. 6±2. 1keV,whlch is fitted within the error extent to 26. 0±2. 4keV monoenergetic Xrays 相似文献