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Phase function metod for elastic nucleon-nucleon scattering using Hellmann plus Coulomb potential 用赫尔曼加库仑势计算弹性核子-核子散射的相函数法
4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-11-01 DOI: 10.31349/revmexfis.69.061201
Bidhan Khirali, B. Swain, A. K. Behera, U. Laha
The phase function method/variable phase approach to potential scattering is exploited to calculate the phase shifts for nucleon-nucleon systems in low and intermediate energy regions by representing nuclear part of the interaction by the Hellmann potential while the electromagnetic part by the Coulomb one. In addition, the differential and total scattering cross sections are estimated with our phase parameters. Results reproduced by the concerned potential are in good agreement with the previous works in the literature.
利用位散射的相函数法/变相法计算中低能区核子-核子系统的相移,用赫尔曼势表示相互作用的核部分,用库仑势表示相互作用的电磁部分。此外,用我们的相位参数估计了微分散射截面和总散射截面。相关电位重现的结果与文献中已有的结果一致。
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引用次数: 0
Misapplication of the parametric statistics to calculate the uncertainties when calibrating commercial spectrocolorimeters 校正商用分光比色计时,参数统计在计算不确定度时的错误应用
4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-11-01 DOI: 10.31349/revmexfis.69.061304
Sandra Eloísa Balderas-Mata, O. Ramos Soto, J. Medina Márquez
Nowadays, when calibrating spectrocolorimeters, the uncertainties are calculated based on the premise that the obtained measurements have a Gaussian distribution, but there is no certainty that the latter is completely true. The aim of this work is to show that, when measuring reference materials with different spectrocolorimeters, most of the results do not have, for all the points in the visible spectrum of the spectral curve, a Gaussian distribution. Also, this distribution is not present in measurements of the chromatic coordinates of these materials. These measurements were performed with two integrating sphere spectrocolorimeters; a Minolta 2600d r (portable) and a Gretag Macbeth 7000 r (bench) equipment, under the same measurement parameters and conditions of repeatability, as well as controlled environmental conditions, i.e., 20 ± 1 ◦C. Since a Gaussian distribution is needed to use parametric statistics to calculate the combined uncertainties and consequently, the expanded ones, the statistical method currently used is erroneous. Thus, parametric statistics should not be used to calculate the spectrocolorimeters’ uncertainties.
目前,在标定分光比色仪时,不确定度的计算是以得到的测量值服从高斯分布为前提的,但不确定高斯分布是否完全正确。本工作的目的是表明,当用不同的分光比色仪测量标准物质时,大多数结果并不具有光谱曲线中可见光谱中的所有点的高斯分布。同样,这种分布在测量这些材料的色坐标时也不存在。这些测量是用两个积分球分光比色仪进行的;一台Minolta 2600d r(便携式)和一台Gretag Macbeth 7000 r(台式)设备,在相同的测量参数和可重复性条件下,以及受控的环境条件,即20±1◦C。由于高斯分布需要使用参数统计来计算组合不确定性,因此需要使用扩展的不确定性,因此目前使用的统计方法是错误的。因此,不应使用参数统计来计算分光比色计的不确定度。
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引用次数: 0
Landau levels for a Weyl pair in a monolayer medium and thermal quantities 单层介质中Weyl对的朗道能级和热量
4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-11-01 DOI: 10.31349/revmexfis.69.061701
Abdullah Guvendi, Abdelmalek Boumali
In this paper, we consider a Weyl pair under the effect of an external uniform magnetic field in a monolayer medium without considering any charge-charge interaction between the particles. Choosing the interaction of the particles with the magnetic field in the symmetric gauge we seek for an analytical solution of the corresponding form of a one-time fully-covariant two-body Dirac equation derived from quantum electrodynamics via the action principle. As it is usual with two-body problems, we separate the relative motion and center of mass motion coordinates. Assuming the center of mass is at rest, we derive a matrix equation in terms of the relative motion coordinates without considering any group theoretical method. This equation gives a wave equation in exactly soluble form and accordingly we obtain the spinor components and complete energy eigen-states (in closed form) for such a spinless composite structure. Our results not only give exact Landau levels for such a Weyl pair in a monolayer medium but also show the considered system behaves as a two-dimensional harmonic oscillator. Furthermore, our findings give exactly the excited states of a Weyl particle under the effect of uniform external magnetic field in a monolayer graphene sheet and there is no imprint to distinguish these modes from each other. This means that the performed experiments based on Landau levels for a monolayer graphene sheet may actually involve many-body effects. Our results provide a suitable basis to analyze the associated thermal quantities and accordingly we discuss the thermal properties by determining free energy, total energy, entropy and specific heat for the composite system in question.
在本文中,我们考虑了外均匀磁场作用下单层介质中的Weyl对,而不考虑粒子之间的电荷相互作用。选取对称规范中粒子与磁场的相互作用,利用作用原理,从量子电动力学推导出一次性全协变二体狄拉克方程,寻求其相应形式的解析解。与通常的两体问题一样,我们将相对运动坐标和质心运动坐标分开。假设质心处于静止状态,在不考虑任何群论方法的情况下,导出了相对运动坐标下的矩阵方程。该方程给出了一个完全可溶形式的波动方程,从而得到了这种无自旋复合结构的旋量分量和完全能量本征态(闭态)。我们的结果不仅给出了这种Weyl对在单层介质中的精确朗道能级,而且还显示了所考虑的系统表现为二维谐振子。此外,我们的研究结果准确地给出了Weyl粒子在单层石墨烯片上均匀外磁场作用下的激发态,并且没有印记来区分这些模式。这意味着基于朗道能级对单层石墨烯片进行的实验实际上可能涉及多体效应。我们的结果为分析相关的热量提供了一个合适的基础,因此我们通过确定所讨论的复合系统的自由能、总能、熵和比热来讨论热性质。
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引用次数: 0
Pressure dependence on Raman spectra of the molecular crystal 4-(benzenesulfonyl)-morpholine 4-(苯磺酰)-啉分子晶体拉曼光谱的压力依赖性
4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-11-01 DOI: 10.31349/revmexfis.69.060502
Thiago Andrade De Toledo, Eduardo Delmondes Silva, Jorge Luiz Brito de Faria, Luiz Everson Da Silva, Paulo Sérgio Pizani
The structural and vibrational properties of 4-(benzenesulfonyl)-morpholine, C10H13NO3S, have been studied using multinuclear (1H and 13C) NMR, IR and Raman spectroscopy techniques at pressures up to 3.2 GPa, as well as molecular modeling and vibrational mode assignment using DFT calculations with B3LYP functional and 6-31G (d,p) basis set and potential energy distribution (PED). Experimental and calculated spectra were compared and showed good accuracy. The sample was subjected to high pressure in the range of 0 to 3.2 GPa. The pressure measurements suggest a conformational transition for values around 0.7, 1.7 and 2.5 GPa, which was observed in some spectral regions, mainly in the high energy vibrational bands.
利用多核(1H和13C)核磁共振、红外和拉曼光谱技术,研究了4-(苯磺酰基)-啉C10H13NO3S在3.2 GPa压力下的结构和振动特性,并利用B3LYP功能和6-31G (d,p)基集和势能分布(PED)进行了分子建模和振动模式分配。实验光谱与计算光谱进行了比较,显示出较好的精度。样品承受0 ~ 3.2 GPa的高压。压力测量结果表明,在0.7、1.7和2.5 GPa附近存在构象转变,这种转变主要发生在一些光谱区域,主要是在高能振动带。
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引用次数: 0
Pseudoscalar current and covariance with the light-front approach 伪标量电流和与光前方法的协方差
4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-11-01 DOI: 10.31349/revmexfis.69.060801
Jurandi Leão, Joao De Mello
Quantum Field Theory (QFT) is used to describe the physics of particles in terms of their fundamental constituents. The Light-Front Field Theory (LFFT), introduced by Paul Dirac in 1949 [1], is an alternative approach to solve some of the problems that arise in quantum field theory. The LFFT is similar to the Equal Time Quantum Field Theory (EQT), however, some particularities are not, such as the loss of covariance in the light-front. Pion electromagnetic form factor is studied in this work at lower and higher momentum transfer regions to explore the constituent quark models and the differences among these and other models. The electromagnetic current is calculated with both the “plus” and “minus” components in the light-front approach. The results are compared with other models, as well as with experimental data.
量子场论(QFT)是用来描述粒子的基本成分方面的物理。由Paul Dirac于1949年提出的光前沿场论(Light-Front Field Theory, LFFT)[1]是解决量子场论中出现的一些问题的另一种方法。LFFT与等时间量子场论(EQT)相似,但有一些特性不同,如光前协方差的损失。本文在低动量传递区和高动量传递区研究了介子电磁形状因子,探讨了组成夸克模型及其与其他模型的区别。在光前方法中,电磁电流是用“正”和“负”分量计算的。结果与其他模型以及实验数据进行了比较。
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引用次数: 0
Effect of slide burnishing on corrosion potential in ASTM A-36 steel 滑动抛光对ASTM A-36钢腐蚀电位的影响
4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-11-01 DOI: 10.31349/revmexfis.69.061002
A. Saldaña-Robles, M. Zapata-Torres, J. Moreno-Palmerin, Alfredo Márquez-Herrera
This study investigates the corrosion potential of ASTM A-36 steel after slide burnishing using different applied forces. Turned samples of ASTM A-36 steel were subjected to slide burnishing surface treatment. The burnishing process was carried out with forces of 150 N, 300 N, and 450 N, at a travel speed of 100 mm/min. The effects of burnishing on the chemical composition of the material were analyzed using Grazing Incidence X-ray Diffraction and X-ray photoelectron spectroscopy, which indicated no changes in the chemical composition of the material. Corrosion potential measurements were performed using the Tafel test. The results showed that as the burnishing force increased, the corrosion potential shifted to lower values. Additionally, roughness analysis suggested that the change in corrosion potential was attributed to plastic deformation caused by the burnishing process. The increased mechanical work exerted on the material during burnishing may be the underlying reason for the observed shift towards lower corrosion potentials with higher applied forces.
本研究考察了ASTM A-36钢在使用不同的外力进行滑动抛光后的腐蚀潜力。ASTM A-36钢的车削样品进行滑动抛光表面处理。抛光过程在150牛、300牛和450牛的力下进行,运行速度为100毫米/分钟。利用掠入射x射线衍射和x射线光电子能谱分析了抛光对材料化学成分的影响,表明材料的化学成分没有变化。腐蚀电位测量采用Tafel试验。结果表明,随着抛光力的增大,腐蚀电位逐渐减小。此外,粗糙度分析表明,腐蚀电位的变化归因于抛光过程引起的塑性变形。在抛光过程中施加在材料上的机械功的增加可能是观察到的在较高的作用力下向较低腐蚀电位转变的潜在原因。
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引用次数: 0
Electromagnetic curves and Rytov’s law in the optical fiber with Maxwellian evolution via alternative moving frame 交替运动框架下光纤中的电磁曲线和雷托夫定律的麦克斯韦演化
4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-11-01 DOI: 10.31349/revmexfis.69.061301
Semra Nurkan, Hazal Ceyhan, Zehra Özdemir, İsmail Gök
In this study, we research the behavior of a linearly-polarized light wave in optical fiber and the rotation of the polarization plane through the alternative moving frame { N,C,W } in Minkowski 3-space. Then Berry’s phase equations are discussed for electromagnetic curves in the { C } and { W } directions along an optic fiber via alternative moving frame in Minkowski 3-space. Moreover, electromagnetic curve’s { C } and { W } Rytov parallel transportation laws are defined. Finally, we examine the electromagnetic curve’s Maxwellian evolution by Maxwell’s equation.
在本研究中,我们研究了线偏振光在光纤中的行为以及偏振面在闵可夫斯基三维空间中通过可选运动坐标系{N,C,W}的旋转。然后讨论了在闵可夫斯基三维空间中沿光纤沿可选运动框架沿{C}和{W}方向的电磁曲线的Berry相位方程。定义了电磁曲线的{C}和{W} Rytov平行输运定律。最后,我们用麦克斯韦方程考察了电磁曲线的麦克斯韦演化。
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引用次数: 0
Stable identification of sources located on the cerebral cortex from EEG over the scalp 通过头皮上的脑电图稳定地识别位于大脑皮层上的源
IF 1.7 4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-09-01 DOI: 10.31349/revmexfis.69.050702
José Ángel Arias Cruz, M. M. Morín Castillo, J. O. Oliveros Oliveros, José Eligio Moisés Gutiérrez Arias
In this work, we present a stable algorithm for the inverse problem of identifying cortical sources from electroencephalographic measurements on the scalp. This inverse problem is ill-posed due to the numerical instability it presents, i.e., small changes in the measurements can produce large variations in the location of the sources. A boundary value problem is used to find correlations between the sources and measurements. In the case in which the head is modeled using two concentric spheres. We use spherical harmonics to find the solution to the inverse source cortical problem. To handle the numerical instability of this problem, we use the Tikhonov regularization method and a cut-off of the harmonic expansion series. From numerical tests, we found these parameters with which we get good approximations. Finally, we illustrate the algorithm proposed with synthetic examples
在这项工作中,我们提出了一种稳定的算法,用于从头皮上的脑电图测量中识别皮层源的反问题。这个反问题是不适定的,因为它所呈现的数值不稳定性,即测量值的微小变化会导致源位置的大变化。边值问题用于发现源和测量值之间的相关性。在这种情况下,头部是用两个同心球体来建模的。我们用球面谐波来求逆源皮质问题的解。为了处理这一问题的数值不稳定性,我们使用了Tikhonov正则化方法和谐波展开级数的截止。从数值试验中,我们找到了这些参数,我们得到了很好的近似。最后,用综合算例对算法进行了说明
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引用次数: 0
Raman and FTIR spectroscopy experimental and theoretical in magnetic nanoemulsion from Carapa Guianensis Aublet 桂树磁性纳米乳液的拉曼光谱和红外光谱实验与理论研究
IF 1.7 4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-09-01 DOI: 10.31349/revmexfis.69.051003
L.G.F. Silva, Q.S. Martins, A. Ribas, D.L.L. Oliveira, R.C.S. Lima, J.G. Santos
This work brings Raman and Fourier transform infrared (FTIR) spectroscopy as a proposal for a vibrational characterization of Carapa Guianensis Aublet essential oil in natura and polymerized and of magnetic nanoemulsion. Calculation of computational chemistry based on the method density functional theory with B3LYP functional and 6-311+G(d,p) base set parameters was used to obtain theoretical frequencies and vibrational signatures of the oleic acid molecule. Results of Raman and Fourier transform infrared spectroscopy confirm bands of Carapa Guianensis Aublet essential oil present in polymerized oil and magnetic nanoemulsion studied. The density functional theory method shows that the bands 1099 cm-1, 1714 cm-1 and 1812 cm-1 explain the presence of vibrational modes of oleic acid in the samples. The density functional theory brought good conformation to the chosen molecule.
本研究将拉曼光谱和傅里叶变换红外光谱(FTIR)应用于天然、聚合和磁性纳米乳液中桂枝精油的振动表征。基于B3LYP泛函和6-311+G(d,p)基集参数的密度泛函方法进行计算化学计算,得到油酸分子的理论频率和振动特征。拉曼和傅里叶红外光谱结果证实了桂枝精油在聚合油和磁性纳米乳中存在的谱带。密度泛函理论方法表明,1099 cm-1、1714 cm-1和1812 cm-1波段可以解释油酸在样品中存在的振动模式。密度泛函理论为所选分子带来了良好的构象。
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引用次数: 0
Stability improvement of CH3NH3PbI3 hybrid perovskite through tin and chlorine doping 锡和氯掺杂提高CH3NH3PbI3杂化钙钛矿的稳定性
IF 1.7 4区 物理与天体物理 Q3 Physics and Astronomy Pub Date : 2023-09-01 DOI: 10.31349/revmexfis.69.051602
Bertha Oliva Aguilar Reyes, T. E. Soto, K. Sánchez, O. Navarro, A. Valdespino, D. Y. Torres Martínez
In recent years, the hybrid perovskite CH3NH3PbI3 has been widely studied because of its potential application in the fabrication of high efficiency solar cells. The main challenge is to avoid destabilization of this compound under working conditions. Indeed, the MAPbI3 begins to decompose into the precursor phases, a few hours or days after being formed. We reported a stability monitoring of doped compounds CH3NH3Pb0.9Sn0.1I2.8Cl0.2 and CH3NH3Pb0.75Sn0.25I2.5Cl0.5 obtained as films from solutions of the precursors in N-N dimethylformamide on chemically treated glass substrates. The monitoring was carried out using X-Ray diffraction and absorbance measurements in the UV-Vis region. The tetragonal symmetry initially determined for the three compounds, remains almost unaltered for CH3NH3Pb0.75Sn0.25I2.5Cl0.5 even after 600 days, under environmental conditions. The bandgap value for this doped perovskite is 1.44 eV.
近年来,杂化钙钛矿CH3NH3PbI3因其在高效太阳能电池制造中的潜在应用而受到广泛的研究。主要的挑战是避免这种化合物在工作条件下的不稳定。事实上,MAPbI3在形成几小时或几天后就开始分解成前体阶段。我们报道了用N-N二甲基甲酰胺前驱体溶液在化学处理过的玻璃衬底上得到的掺杂化合物CH3NH3Pb0.9Sn0.1I2.8Cl0.2和CH3NH3Pb0.75Sn0.25I2.5Cl0.5作为薄膜的稳定性监测。利用x射线衍射和紫外-可见区吸光度测量进行监测。在环境条件下,CH3NH3Pb0.75Sn0.25I2.5Cl0.5的四方对称性即使在600天后也几乎保持不变。掺钙钛矿的带隙值为1.44 eV。
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引用次数: 0
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