STRUCTURE, DYNAMICS, AND FORMATION OF CARBON AND ALUMINUM CLUSTERS

1992 ◽  
Vol 06 (23n24) ◽  
pp. 3667-3673
Author(s):  
Q.-M. Zhang ◽  
J.-Y Yi ◽  
C.J. Brabec ◽  
E.B. Anderson ◽  
B.N. Davidson ◽  
...  
Keyword(s):  
High Temperatures ◽  
Short Range ◽  
Ab Initio Molecular Dynamics ◽  
Scattering Data ◽  
Cage Structure ◽  
Aluminum Clusters ◽  
The Individual ◽  
Atomic And Electronic Structure ◽  
Good Agreement ◽  
The Ideal

The results of recent ab initio molecular dynamics studies of C and Al clusters are presented. The simulations have shown that C 60 molecular structure is well preserved in the solid and that the individual C 60 molecules start to rotate at relatively low temperatures. Our results are in very good agreement with NMR, photoemission, and neutron scattering data. At high temperatures C 60 undergoes large amplitude soccerball-rugbyball oscillations, but the cage structure is still preserved. The C 60 isomer containing two pairs of adjacent pentagons has a binding energy only 1.6 eV smaller than that of perfect C 60, but high temperatures and long annealing times are required for the transformation between these two structures. Its activation energy is 5.4 eV. We have also studied the various isomers of C 20, since it could form the smallest possible fullerene. At T=0 , the lowest energy isomer is indeed a dodecohedral structure. However, high temperatures favor the corannulene structure, which is a perfect precursor for the formation of C 60. These results are consistent with the experimental data, since high temperatures are needed for efficient formation of C 60. The atomic and electronic structure and doping properties of semiconducting microtubules have also been investigated. The distortions from the ideal geometries are small in microtubules. Substitutional N and B are effective shallow donors and acceptors, respectively. For Al clusters, we focused on Al 13 and Al 55, which can assume perfect icosahedral and cubic structures. However, the distortions from these ideal structures are substantial. For Al 55, several inequivalent but nearly energetically degenerate structures are found. It is shown that this is due to the short range of the screened interatomic interactions.

Short-range-order determination in quenched NbC0.73 by elastic diffuse neutron scattering

1990 ◽  
Vol 23 (6) ◽  
pp. 497-508 ◽  
Author(s):  
B. Beuneu ◽  
T. Priem ◽  
C. H. de Novion ◽  
S. Lefebvre ◽  
J. Chevrier ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Scattering Data ◽  
Metal Atoms ◽  
Least Squares Fit ◽  
Order Determination ◽  
Good Agreement ◽  
Diffuse Neutron

The elastic diffuse neutron scattering of an NbC0.73 single-crystal has been measured at room temperature on two different spectrometers, the four-circle D10 at the HFR–ILL (Grenoble), and the two-axis G44 with time-of-flight analysis at the Laboratoire Léon Brillouin (Saclay). The data were treated either by Fourier transformations or by least-squares fit. The short-range-order parameters and the interatomic static displacements obtained by the various experiments and/or data treatment are in good agreement: carbon vacancies tend to be third neighbours in the f.c.c. metalloid sublattice and metal atoms relax away from the vacancy first neighbours by ~0.05 Å. It is shown that the treatment of diffuse scattering data limited to two reciprocal planes [(001) and (1{\bar 1}0)] gives satisfactory results.

The Republic

2019 ◽  
pp. 205-229
Author(s):  
Dominic Scott
Keyword(s):  
Political Theory ◽  
Left Behind ◽  
Ideal State ◽  
The Republic ◽  
Individual Justice ◽  
The Individual ◽  
Political Right ◽  
First Time ◽  
The Ideal

This chapter presents a reading of Plato’s Republic. The Republic is among Plato’s most complex works. From its title, the first-time reader will expect a dialogue about political theory, yet the work starts from the perspective of the individual, coming to focus on the question of how, if at all, justice contributes to an agent’s happiness. Only after this question has been fully set out does the work evolve into an investigation of politics—of the ideal state and of the institutions that sustain it, especially those having to do with education. But the interest in individual justice and happiness is never left behind. Rather, the work weaves in and out of the two perspectives, individual and political, right through to its conclusion. All this may leave one wondering about the unity of the work. The chapter shows that, despite the enormous range of topics discussed, the Republic fits together as a coherent whole.

Embodying the culture of achievement: Culture between illness and perfection is a ‘thin line’ – obtaining the ideal female body as an act of achievement

2021 ◽  
pp. 1354067X2110040
Author(s):  
Josefine Dilling ◽  
Anders Petersen
Keyword(s):  
Experimental Study ◽  
Human Body ◽  
Female Body ◽  
The Body ◽  
Thin Line ◽  
Complex Processes ◽  
The Individual ◽  
Different Levels ◽  
The Ideal ◽  
Body Ideals

In this article, we argue that certain behaviour connected to the attempt to attain contemporary female body ideals in Denmark can be understood as an act of achievement and, thus, as an embodiment of the culture of achievement, as it is characterised in Præstationssamfundet, written by the Danish sociologist Anders Petersen (2016) Hans Reitzels Forlag . Arguing from cultural psychological and sociological standpoints, this article examines how the human body functions as a mediational tool in different ways from which the individual communicates both moral and aesthetic sociocultural ideals and values. Complex processes of embodiment, we argue, can be described with different levels of internalisation, externalisation and materialisation, where the body functions as a central mediator. Analysing the findings from a qualitative experimental study on contemporary body ideals carried out by the Danish psychologists Josefine Dilling and Maja Trillingsgaard, this article seeks to anchor such theoretical claims in central empirical findings. The main conclusions from the study are used to structure the article and build arguments on how expectations and ideals expressed in an achievement society become embodied.

scholarly journals Correlation analysis of resected breast tissue and implant volume after mastectomy and its association with breast density

2021 ◽  
Author(s):  
Wolfram Malter ◽  
Bo Jan Bachmann ◽  
Barbara Krug ◽  
Martin Hellmich ◽  
Max Zinser ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Breast Density ◽  
Breast Tissue ◽  
Mathematical Function ◽  
Breast Cancer Patients ◽  
Tissue Weight ◽  
Implant Selection ◽  
Volume Measurements ◽  
The Individual ◽  
The Ideal

Abstract Background The current methods for calculating the ideal implant volume for breast reconstruction are based on pre- or intraoperative volume measurements of the existing breast volume and do not take into account the individual breast density of the woman. This study aims is to identify objective parameters that can help to improve the optimal implant selection. Materials and methods This retrospective analysis includes 198 breast cancer patients who underwent mastectomy. Breast densities (ACR) measured in mammography and MRI were compared with the removed breast tissue weight and volume of the implants used. In addition, the resected weight was compared directly with the implant volume to calculate a mathematical function. Results There was no significant correlation between the ACR values and the resected weights [correlation coefficient: mammography:− 0.117 (p = 0.176), MRI − 0.033 (p = 0.756)]. A negative correlation between the implant volumes and both imaging methods could be demonstrated [correlation coefficient: mammography − 0.268; p = 0.002; MRI was − 0.200 (p = 0.055)]. A highly significant correlation between the resected weights and the implant volumes (correlation coefficient 0.744; p < 0.001) was observed. This correlation corresponds to a power function (y = 34.71 x0.39), in which any resected weight can be used for the variable x to calculate the implant volume. Conclusion We were able to show that there is a significant correlation between the resected breast tissue and the implant volume. With our novel potency function, the appropriate implant volume can be calculated for any resected weight making it easier for the surgeon to choose a fitting implant in a simple and more objective manner.

Short range orders in molten Al: An ab initio molecular dynamics study

2014 ◽  
Vol 93 ◽  
pp. 97-103 ◽  
Author(s):  
Jianbo Ma ◽  
Yongbing Dai ◽  
Wei Zhou ◽  
Jiao Zhang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Short Range ◽  
Ab Initio Molecular Dynamics

Expressions for the effective diffusivity in materials with interphase boundaries

2004 ◽  
Vol 819 ◽  
Author(s):  
Irina V. Belova ◽  
Graeme E. Murch
Keyword(s):  
Polycrystalline Material ◽  
Effective Diffusivity ◽  
Poor Agreement ◽  
Two Phase ◽  
Interphase Boundaries ◽  
Long Time ◽  
Simulation Results ◽  
The Individual ◽  
Individual Grains ◽  
Good Agreement

AbstractWe address the problem of calculating the long-time-limit effective diffusivity in stable two- phase polycrystalline material. A phenomenological model is used where the high diffusivity interphase boundaries are treated as connected “coatings” of the individual grains. Derivation of expressions for the effective diffusivity with segregation is made along Maxwell lines. Monte Carlo simulation using lattice-based random walks is used to test the validity of the expressions. It is shown that for the case analysed the derived expressions for the effective diffusivity are in very good agreement with simulation results. The equivalent of the Hart equation is also derived. It is shown to be in poor agreement with simulation results.

scholarly journals Accuracy of Wind Observations from Open-Ocean Buoys: Correction for Flow Distortion

2020 ◽  
Vol 37 (4) ◽  
pp. 687-703 ◽  
Author(s):  
Michael Schlundt ◽  
J. Thomas Farrar ◽  
Sebastien P. Bigorre ◽  
Albert J. Plueddemann ◽  
Robert A. Weller
Keyword(s):  
Flow Distortion ◽  
Error Sources ◽  
Neutral Winds ◽  
Flow Simulations ◽  
Temporal Sampling ◽  
Empirical Correction ◽  
The Individual ◽  
Wind Vane ◽  
Subsequent Comparison ◽  
Good Agreement

AbstractThe comparison of equivalent neutral winds obtained from (i) four WHOI buoys in the subtropics and (ii) scatterometer estimates at those locations reveals a root-mean-square (RMS) difference of 0.56–0.76 m s−1. To investigate this RMS difference, different buoy wind error sources were examined. These buoys are particularly well suited to examine two important sources of buoy wind errors because 1) redundant anemometers and a comparison with numerical flow simulations allow us to quantitatively assess flow distortion errors, and 2) 1-min sampling at the buoys allows us to examine the sensitivity of buoy temporal sampling/averaging in the buoy–scatterometer comparisons. The interanemometer difference varies as a function of wind direction relative to the buoy wind vane and is consistent with the effects of flow distortion expected based on numerical flow simulations. Comparison between the anemometers and scatterometer winds supports the interpretation that the interanemometer disagreement, which can be up to 5% of the wind speed, is due to flow distortion. These insights motivate an empirical correction to the individual anemometer records and subsequent comparison with scatterometer estimates show good agreement.

scholarly journals Young People: Between Literature and Advanced Technologies

2017 ◽  
Vol 1 (1) ◽  
pp. 13-23
Author(s):  
Ahmad Idris Asmaradhani
Keyword(s):  
Life Choices ◽  
Face To Face ◽  
Human Essence ◽  
The Past ◽  
Technological Advances ◽  
The World ◽  
Simple Question ◽  
The Media ◽  
The Individual ◽  
The Ideal

In the eyes of literature, existentialist thinkers focus on the question of concrete human existence and the conditions of this existence rather than hypothesizing a human essence, stressing that the human essence is determined through life choices. The ideal, however, is that humans exist in a state of distance from the world that they nonetheless remain in the midst of. This distance is what enables humans to project meaning into the disinterested world of in-itselfs. This projected meaning remains fragile, constantly facing breakdown for any reason— from a tragedy to a particularly insightful moment. In such a breakdown, humans are put face to face with the naked meaninglessness of the world, and the results can be devastating. It is porposed that literature and the media combined have a powerful impact on those who wish to truly realize and understand their message. By studying, reading, learning, experiencing, and knowing the culture of the present and those cultures of the past then one can understand the ideas of life and how the two work together to help us better understand each other and ourselves. In what ways our present culture, our technological advances, and the media shape who we are as individuals is not a simple question. The answer seems to elusively hide in a world filled with cultural complexities. But, it is no secret to find that literature is a source of power. It does influence, guide, and shape the human become as they continue their journey through life. Hence, since human are never without the influence of literature, they will always have factors working to modify the human being. However, it is their choice as to how they internalize what they are exposed to, and in turn, it is up to them to determine the individual that ultimately prevails.

scholarly journals A Radiomics nomogram for preoperative predicting recurrence of low grade gliomas based on multiparametric MRI

2021 ◽  
Author(s):  
Zhenhua Wang ◽  
Xinlan Xiao ◽  
Zhaotao Zhang ◽  
Keng He ◽  
Peipei Pang ◽  
...  
Keyword(s):  
Multivariate Logistic Regression Analysis ◽  
Low Grade ◽  
Training Set ◽  
Decision Curve Analysis ◽  
Logistic Analysis ◽  
Contrast Enhanced ◽  
Fluid Attenuated Inversion Recovery ◽  
Validation Set ◽  
The Individual ◽  
Good Agreement

Abstract Objective To develop a radiomics nomogram to predict the recurrence of Low grade glioma(LGG) after their first surgery; Methods A retrospective analysis of pathological, clinical and Magnetic resonance image(MRI) of LGG patients who underwent surgery and had a recurrence between 2017 and 2020 in our hospital was performed. After a rigorous selection,64 patients were eligible and enrolled in the study(22 cases were with recurrent gliomas),which was randomly assigned in a 7:3 ratio to either the training set and validation set; T1WI,T2WI fluid-attenuated-inversion-recovery(T2WI-FLAIR) and contrast-enhanced T1-weighted(T1CE) sequences, 396 radiomics features were extracted from each image sequence, minimum-redundancy maximum-relevancy(mRMR) alone or combining with univariate logistic analysis were used for features screening, the screened features were performed by multivariate logistic regression analysis and developed a predictive model both in training set and validation set; Receiver operating characteristic(ROC) curve, calibration curve, and decision curve analysis(DCA) were used to assess the performance of each model. Results The radiomics nomogram derived from three MRI sequence yielded an ideal performance than the individual ones, the AUC in the training set and validation set were 0.966 and 0.93 respectively, 95% confidence interval(95%CI) were 0.949-0.99 and 0.905-0.973 respectively; the calibration curves indicated good agreement between the predictive and the actual probability. The DCA demonstrated that a combination of three sequences had more favorable clinical predictive value than single sequence imaging. Conclusion Our multiparametric radiomics nomogram could be an efficient and accurate tool for predicting the recurrence of LGG after its first resection.

Theoretical Determination of Absorption With an Emphasis on High Temperatures and a Specific Application to Carbon Monoxide

1973 ◽  
Vol 95 (4) ◽  
pp. 535-538 ◽  
Author(s):  
J. C. Lin ◽  
R. Greif
Keyword(s):  
Carbon Monoxide ◽  
High Temperatures ◽  
Rotational Band ◽  
Experimental Results ◽  
Theoretical Determination ◽  
Hot Band ◽  
Good Agreement

The absorption of a vibrational-rotational band has been studied and the contribution from the first hot band has been included. A specific application has been made to carbon monoxide and good agreement with experimental results has been obtained.

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