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减少Kerr效应法在油纸绝缘结构中直流电场测量误差的方法 被引量:5
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作者 吴昊 齐波 +3 位作者 李成榕 赵晓林 魏振 王国利 《高电压技术》 EI CAS CSCD 北大核心 2013年第5期1149-1155,共7页
Kerr效应法是液体电介质中电场测量的有效方法,但利用该方法在油纸复合绝缘结构中的直流电场准确测量一直是电介质中电场测量的难点。为此,基于Kerr效应法搭建了一套在线非接触式的液体电介质中光学电场测量系统,分析了引起测量系统误... Kerr效应法是液体电介质中电场测量的有效方法,但利用该方法在油纸复合绝缘结构中的直流电场准确测量一直是电介质中电场测量的难点。为此,基于Kerr效应法搭建了一套在线非接触式的液体电介质中光学电场测量系统,分析了引起测量系统误差的主要原因,提出了减小测量误差的方法。通过加长电极和边缘绝缘包覆处理,可将电极边缘效应相对误差减小至1.3%;通过光学器件光学特性的标定,修正了器件非理想因素的误差;通过对激光器噪声的统计分析,合理选取了交流调制电源的频率,提高了测量系统的信噪比,可将激光管同频噪声干扰所导致的直流电场测量相对误差减小到0.86%,交流电场测量相对误差减小到1.6%。经过试验测定,整个测量系统直流电场强度测量灵敏度可达到20V/mm,总体相对误差<5.4%。 展开更多
关键词 kerr效应 测量误差 边缘效应 kerr系数 信噪比 灵敏度
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The Extremal Universe Exact Solution from Einstein’s Field Equation Gives the Cosmological Constant Directly
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作者 Espen Gaarder Haug 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第1期386-397,共12页
Einstein’s field equation is a highly general equation consisting of sixteen equations. However, the equation itself provides limited information about the universe unless it is solved with different boundary conditi... Einstein’s field equation is a highly general equation consisting of sixteen equations. However, the equation itself provides limited information about the universe unless it is solved with different boundary conditions. Multiple solutions have been utilized to predict cosmic scales, and among them, the Friedmann-Lemaître-Robertson-Walker solution that is the back-bone of the development into today standard model of modern cosmology: The Λ-CDM model. However, this is naturally not the only solution to Einstein’s field equation. We will investigate the extremal solutions of the Reissner-Nordström, Kerr, and Kerr-Newman metrics. Interestingly, in their extremal cases, these solutions yield identical predictions for horizons and escape velocity. These solutions can be employed to formulate a new cosmological model that resembles the Friedmann equation. However, a significant distinction arises in the extremal universe solution, which does not necessitate the ad hoc insertion of the cosmological constant;instead, it emerges naturally from the derivation itself. To the best of our knowledge, all other solutions relying on the cosmological constant do so by initially ad hoc inserting it into Einstein’s field equation. This clarification unveils the true nature of the cosmological constant, suggesting that it serves as a correction factor for strong gravitational fields, accurately predicting real-world cosmological phenomena only within the extremal solutions of the discussed metrics, all derived strictly from Einstein’s field equation. 展开更多
关键词 General Relativity Theory Cosmological constant Extremal Solution Reissner-Nordström kerr kerr-Newman
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浸矿过程离子浓度对化学平衡常数阶段性变化规律研究
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作者 郭江 秦磊 +3 位作者 王观石 罗嗣海 彭陈亮 龙平 《中国稀土学报》 北大核心 2025年第3期584-594,共11页
离子型稀土矿浸矿过程以可逆的离子交换为主,定量描述该离子交换过程需要采用化学平衡常数,化学平衡常数受离子浓度影响,因此探究离子浓度的影响对揭示浸矿机制十分重要。本文通过不同浓度硫酸铵与稀土的离子交换实验,分析离子交换反应... 离子型稀土矿浸矿过程以可逆的离子交换为主,定量描述该离子交换过程需要采用化学平衡常数,化学平衡常数受离子浓度影响,因此探究离子浓度的影响对揭示浸矿机制十分重要。本文通过不同浓度硫酸铵与稀土的离子交换实验,分析离子交换反应化学平衡常数(Kerr模型)随离子浓度的变化规律,并且定量刻画化学平衡常数随硫酸铵浓度的变化关系。结果发现:随着浓度的变化,离子交换可以分为三个阶段:(1)当(NH_(4))_(2)SO_(4)浓度低于5 mmol·L^(-1)时,铵根离子以物理吸附为主,化学平衡常数随(NH_(4))_(2)SO_(4)浓度增加而缓慢减小;(2)当(NH_(4))_(2)SO_(4)浓度在5~60 mmol·L^(-1)时,矿土表面的物理吸附态铵达到饱和,铵根离子以离子交换为主,化学平衡常数随(NH_(4))_(2)SO_(4)浓度增加而线性减小;(3)当(NH_(4))_(2)SO_(4)浓度超过60 mmol·L^(-1)时,吸附剂表面的稀土离子吸附位被饱和,铵根离子交换达到其最大值,化学平衡常数随(NH_(4))_(2)SO_(4)浓度增加而负指数减小。并且分别用K_(RE)=acNH_(4)^(+)and K_(RE)=dcNH_(4)^(+)^(-3)公式定量刻画化学平衡常数在第Ⅱ,Ⅲ阶段的变化规律,发现计算值与试验值的相关系数均达到0.99以上,且最大相对误差为8.68%,说明该公式可以定量描述浸矿过程各物理量间的关系,揭示了浸矿机理,为生产现场浸矿剂用量确定提供理论支持。 展开更多
关键词 离子型稀土矿 物理吸附 离子交换吸附 kerr模型 化学平衡常数
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溅射制备Pt_(1-x)Co_x(x=0.2~0.4)合金膜的基本光学和磁光常数
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作者 荀坤 刘铸 +3 位作者 周健 郑玉祥 沈德芳 陈良尧 《功能材料与器件学报》 CAS CSCD 1998年第4期250-256,共7页
在光子能量为1.5eV~4.8eV的范围内,测量了用溅射合金靶方法制备的易磁化方向垂直于膜面的Pt1-xCox(x=0.2~0.4)合金膜的光学常数和磁光常数。该合金膜的光学常数对成份极不敏感。磁光常数随Co成份的增... 在光子能量为1.5eV~4.8eV的范围内,测量了用溅射合金靶方法制备的易磁化方向垂直于膜面的Pt1-xCox(x=0.2~0.4)合金膜的光学常数和磁光常数。该合金膜的光学常数对成份极不敏感。磁光常数随Co成份的增加而增加。克尔转角在光子能量为4.2eV附近的峰值随Co成份的增大可用费米面附近d电子轨道态密度和Pt5d电子极化的增大来解释。本文还讨论了Pt1-xCox合金膜的本征和潜在品质因子。 展开更多
关键词 磁光克尔效应 光学常数 铂钴合金 合金膜
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蓝相液晶光电特性研究 被引量:6
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作者 倪水彬 朱吉亮 +1 位作者 钟恩伟 陆建钢 《液晶与显示》 CAS CSCD 北大核心 2012年第6期719-723,共5页
蓝相液晶由于其特有的扭曲双螺旋结构,具有快速响应特性与宏观上的光学各向同性。通过聚合物稳定的方法,可以提升其热稳定性,但是也导致了驱动性能下降,磁滞效应增强等问题。文章通过研究手性掺杂和聚合物网络对蓝相液晶材料体系的作用... 蓝相液晶由于其特有的扭曲双螺旋结构,具有快速响应特性与宏观上的光学各向同性。通过聚合物稳定的方法,可以提升其热稳定性,但是也导致了驱动性能下降,磁滞效应增强等问题。文章通过研究手性掺杂和聚合物网络对蓝相液晶材料体系的作用以及不同温度下的磁滞效应,探索蓝相液晶器件光电特性的影响因子,为改善蓝相液晶材料的光电特性提供理论上的支持。 展开更多
关键词 蓝相液晶 手性掺杂 科尔常数 磁滞效应
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Toward a Common Ground for Gravity and Optics
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作者 Jose L. Parra 《Journal of Applied Mathematics and Physics》 2018年第9期1896-1906,共11页
A long enough period of observation of the Sun’s gravitational dragging effects by using a modified Cavendish’s balance output of experimental evidence shows new patterns. Those patterns can be explained assuming th... A long enough period of observation of the Sun’s gravitational dragging effects by using a modified Cavendish’s balance output of experimental evidence shows new patterns. Those patterns can be explained assuming that the Sun has a torus with rotation, precession, and nutation. This purpose of this paper is to introduce the frequencies of all those movements. The torus’s rotational period can be used to explain the Sun’s magnetic pole reversal. Utilizing a modified Cavendish’s balance showed an output of dragging forces stronger than the attraction between the gravitational masses. This tool afforded this research a new experimental possibility to a more precise determination of the Universal Gravitational Constant Big G. Moreover, the dragging forces directly affect any volume of mass, which includes the atmosphere. This paper shows a correlation between the Sun’s dragging peaks and density of the air squared. The aforementioned correlation and the inverse cubic relation with the distance to the Sun are common for the dragging and tide forces providing the possibility that tidal forces are also a gravitational dragging consequence. The last 2017 total Solar eclipse created a new temporal reaction on the modified Cavendish’s balance. That temporal pattern looks as the spatial pattern created by an opaque disk. This similarity allows the researcher to calculate that the dragging forces are transmitted by photons with spatial periodicity of value λ = 6.1 km. 展开更多
关键词 SPINNING Black HOLES kerr’s Metric General RELATIVITY TORSION Measurements GRAVITATIONAL constant G Rotation PRECESSION Solar Cycles
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The Implications of the Sun’s Dragging Effect on Gravitational Experiments
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作者 Jose L. Parra 《International Journal of Astronomy and Astrophysics》 2017年第3期174-184,共11页
Experimental determinations of Newton’s gravitational constant, Big G, have increased, in number and precision, during the last 30 years. There is, however, a persistent discrepancy between various authors. After exa... Experimental determinations of Newton’s gravitational constant, Big G, have increased, in number and precision, during the last 30 years. There is, however, a persistent discrepancy between various authors. After examining some literature proposing that the differences in Big G might be a function of the length of the day along the years, this paper proposes an alternative hypothesis in which the periodicity of said variation is a function of the relative periodicity of the Sun-Earth distance. The hypothesis introduced here becomes a direct application of the Kerr Metric that describes a massive rotating star. The Kerr solution for the equations of the General Theory of Relativity of Albert Einstein fits well with this relative periodicity and adequately predicts the arrangement of the ex-perimental G values reported by sixteen different laboratories. Also, the author explains how the Sun disturbs gravity on the surface of the Earth. 展开更多
关键词 SPINNING Black Holes kerr’s Metric General RELATIVITY Torsion Measurements GRAVITATIONAL constant G PRECESSION
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匀速直线运动的克尔-纽曼黑洞的吸积
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作者 焦磊 杨荣佳 张建飞 《科学通报》 EI CAS CSCD 北大核心 2017年第9期938-943,共6页
天体的物质吸积一直是天体物理学家感兴趣的现象,人们也已经得到了若干黑洞吸积的精确解.本文研究了一个作匀速直线运动的克尔-纽曼黑洞的吸积问题,获得一个解析解.将参考系选为黑洞静止参考系,将物质流近似为理想流体且旋度为零,流的... 天体的物质吸积一直是天体物理学家感兴趣的现象,人们也已经得到了若干黑洞吸积的精确解.本文研究了一个作匀速直线运动的克尔-纽曼黑洞的吸积问题,获得一个解析解.将参考系选为黑洞静止参考系,将物质流近似为理想流体且旋度为零,流的速度矢量hu_μ可以表达为一个势ψ的梯度.得到势ψ所满足的微分方程(ψ^(,a));_a=0在克尔-纽曼黑洞时空的具体形式.在两个边界条件(即无穷远处势ψ的表达式和粒子数n在外事件视界上的有限性)下求得势ψ的微分方程的解.利用此解计算速度矢量各分量nu_μ,发现一般情况下,吸积流是三维的,即是空间3个坐标(r,θ,ф)的函数,不具备球对称性和轴对称性.最后计算出物质吸积速率,此速率取决于黑洞基本参量质量、电荷和角动量. 展开更多
关键词 克尔-纽曼黑洞 以恒定速度运动 吸积 物质吸积速率
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