Prediction and Relation of Thermal Conductivity with Average Relative Atomic Mass and Density for Semiconducting Compound Functional Crystal Materials

2007 ◽  
Vol 46 (4A) ◽  
pp. 1441-1443 ◽  
Author(s):  
Qingren Wu ◽  
Yibin Xu ◽  
Tonggeng Xi
2007 ◽  
Vol 280-283 ◽  
pp. 1175-1178
Author(s):  
Qing Ren Wu ◽  
Xiao Ping Wang ◽  
Hua Qing Xie ◽  
Tonggeng Xi

A new method for predicting the thermal conductivity of functional carbide crystals and ceramics materials is proposed. The effect of average relative atomic mass and density on thermal conductivities of carbide function crystals and ceramics is considered in the method. Correlations are developed for thermal conductivity with average relative atomic mass and density according to the microscope theories of heat conduction. The thermal conductivities calculated from the prediction equation for many functional carbide crystals and ceramics were compared with the measured dada and found to be agreement. It is show that, for the most of functional carbide crystals and ceramics materials, the relative error between the predicting values and the measuring data is ± 20%. It is discovered in further analysis that the larger the average relative atomic mass and density are, the more accurately the thermal conductivities predict.


Author(s):  
Shuai-Chuang Wang ◽  
Xin-Gang Liang

A thermal rectifier has such nature that its thermal conductance or thermal conductivity has different values with reversed heat flux direction. This work investigates the rectification of the cross-plane thermal conductivity and interfacial thermal resistance of nanoscale bi-layered films using the nonequilibrium molecular dynamics (NEMD) method. The effects of the thickness of the single layer with the total thickness constant, the ratio of the atomic mass and temperature difference in the two ends on the thermal rectification are all considered. The results of the simulations show that the thermal conductivity and the interfacial thermal resistance are different for the heat flux with opposite directions. For the composite film with two layers of the same thicknesses, the thermal conductivity is larger when the heat flux direction is from the light layer to the heavy one. The difference becomes larger when the ratio of the atomic mass in the two layers increases. Increasing the heat flux makes the rectification of thermal conductivity larger, which means that the rectification is dependent on the temperature. For the composite film with fixed total thickness, the rectification becomes smaller when the thickness of the light layer increases. When the light layer is thick enough, the rectification is found reversed, which means that the thermal conductivity is larger with the heat flux direction from the heavy layer to the light one. The phonon density of states is also calculated to explain the phenomenon, and it is found that the overlap of the phonon density of states for the two layers is almost same even if the rectification of the thermal conductivity is reversed.


2017 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Asih Widi Wisudawati

The study aims to develop instrument to measurethe level of understanding of students and microscopic level material phase changes of water. The method used is R&D (Research and Development) Borg and Gall, which have procedure were are following step (1) Need assessment/ Plan (2) Design product/ Organization (3) Created product/ implementation. Implementation with one shot design study with samples used a number of 71 students of 10th grade MA Wahid Hasyim and senior high school MBS Yogyakarta. Indicators in the study is the movement and vibration of water particles, the distance between water particles, particle kinetic energy of water, relative atomic mass of water and hydrogen bonding. The results showed an understanding of chemica lmaterial microscopic level is low and spitual attitude as a nurturant effect is high categories. 


Author(s):  
Ogaba Philip Obande

Fundamental principles of classical (Newtonian) physics are employed to probe the cosmological lambda Λ; it yields the values ρvac = 2.61 x 10-39 g cm-3 and Λ = 4.78 x 10-62. The results reveal that Λ is a fundamental physical constant defined by vacuum density-light speed ρvacc2 correlation. However, the constant accelerates along the groups and periods of a universal spatial periodicity equivalent to the chemical periodicity. Previous results are cited to show that chemical elements are quantum harmonic (periodic) oscillators QHOs and their waveform oscillations exclusively define the vacuum field. A cosmological periodic unit CPU is introduced, it relies on the cosmological principle to argue that a relative physical quantity evaluated for the QHO applies to constituents of corresponding cosmological spatial quanta. Compelling evidences, backed with relevant data and quantitative expressions, are then presented to argue that: there was never a big bang, it is a Linde-universe sans “chaotic”; nature posts no singularity; mass does not curve spacetime, neither does metric space curvature trace directly to gravitation nor particle creation, gravity is classical, not quantum; reality is quadri-phasic not mono-phasic with a clear distinction between the atomic waveform defined with absolute atomic mass and condensed matter defined with relative atomic mass; every chemical element exists in three particle-generations thus, dark matter is invisible form (conjugate) of the visible element, its waveform manifests dark energy, it is not implicated in metric space expansion; Planck scale does not exist, radioactivity constrains fundamental length.


2019 ◽  
Vol 4 (2) ◽  
pp. 123
Author(s):  
Tomas Istantyo Putro ◽  
Sri Retno Dwi Ariani ◽  
Sri Yamtinah

<p>This study’s aim was to find misconception pattern on partial salt hydrolysis on eleventh grade student science major at SMA Negeri 2 Sukoharjo. Misconception was identified using two-tier diagnostic test completed with CRI supported by observation on learning process also interview. Two-tier diagnostic test composed of 16 questions. The approach of this study was qualitative description which was held in February-June 2018. The subject of this study were the eleventh grade students class IPA 1 and IPA 4 as many as 72 students. According to the result showed that there was misconception on almost every concept’s part. Based on the student answer analysis result shows if the pH, relative atomic mass, and volume were known student were having biggest misconception on counting salt’s mass are, 75%. The reason of misconception that occurs on partial salt hydrolysis is come from the student it self that is student’s uncomplete reasoning pattern.</p>


2016 ◽  
Author(s):  
H. P. Lehmann ◽  
X. Fuentes-Arderiu ◽  
L. F. Bertello

1988 ◽  
Vol 65 (1) ◽  
pp. 16
Author(s):  
Erwin Baumgartner ◽  
Carlos Benitez ◽  
Alicia Fernandez Cirelli ◽  
Luz Lastres Flores

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Quanwen Liao ◽  
Lingping Zeng ◽  
Zhichun Liu ◽  
Wei Liu

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