Hasil untuk "Physics"

E. Fradkin

L. Deslauriers, E. Schelew, C. Wieman

K. Nakamura, K. Hagiwara, K. Hikasa et al.

F. H. Attix

A. Tielens

A. Mackenzie, Y. Maeno

D. E. Gray, I. E. Dayton

S. Cherry, J. Sorenson, M. Phelps

B. Alder, S. Fernbach, M. Rotenberg et al.

S. Eidelman, G. Höhler, R. Chivukula et al.

D. Sherrington

W. Leo, D. Haase

R. Bagnold

W. Newhauser, Rui Zhang

The physics of proton therapy has advanced considerably since it was proposed in 1946. Today analytical equations and numerical simulation methods are available to predict and characterize many aspects of proton therapy. This article reviews the basic aspects of the physics of proton therapy, including proton interaction mechanisms, proton transport calculations, the determination of dose from therapeutic and stray radiations, and shielding design. The article discusses underlying processes as well as selected practical experimental and theoretical methods. We conclude by briefly speculating on possible future areas of research of relevance to the physics of proton therapy.

Xiao-Wen Huang, Jin-Song Zhang, Yi-Shun Bu

In order to study the law of influence of rubber particle size on concrete frost resistance characteristics, this paper systematically evaluates the freeze–thaw characteristics of rubber concrete containing different particle sizes. Rubber concrete containing different particle sizes is subjected to 25, 50, 75, 100, and 125 freeze–thaw cycles. After the freeze–thaw cycles, the specimens are observed or measured for appearance, mass change rate, relative dynamic elastic modulus, internal damage degree, compressive strength, and tensile strength. The results show that the frost resistance of concrete mixed with rubber of different particle sizes is more excellent, and the surface of concrete specimens after different numbers of freezing and thawing cycles shows different degrees of spalling. Meanwhile, due to the presence of rubber, the compressive and tensile strengths of rubberized concrete are significantly inferior. Finally, the microscopic scanning results reveal the mechanism of rubber’s incorporation into concrete. The incorporation of rubber effectively reduces its internal pore development. To summarize, it can be seen that rubber incorporated into concrete is a worthwhile method to consider for frost resistance of engineering materials.

Laura Gough, Rommel Miranda, Matthew Hemm et al.

ABSTRACT The Diffusion of Innovations (DOI) model can be used to explore how faculty prioritize learning about and adopting new pedagogical approaches. Here, we use the DOI framework to contextualize biology faculty perceptions of a professional development (PD) program designed to help them create a full semester course-based undergraduate research experience (CURE) class at a large, public comprehensive university. PD sessions included exploring self-reflexive identity while fostering inclusive classroom spaces through understanding and interrupting implicit bias and microaggressions. This qualitative study sought to determine 11 biology faculty members’ beliefs about the influence of their year-long PD on their CURE development and teaching practices. Findings suggest that faculty were motivated to teach CUREs for a variety of reasons. A common incentive was integrating research into a CURE to bring their passion into their classroom and to engage more students in research. This may be particularly important at institutions where faculty have a heavy teaching load. Faculty also reported modifying their teaching in their CUREs and other courses to be more inclusive and equitable. The importance of peer interactions in the PD was emphasized repeatedly as faculty learned from experts, the literature, and faculty who had already developed a CURE. Our results illustrate that a community of practice structure can enhance the learning aspect of the community, helping faculty consider their implementation of inclusive, equitable, and high-impact practices as an ongoing educational process for themselves and emphasizing the importance of reflection and iteration in a DOI framework.

Anamaria Hell, Dieter Lüst

Abstract We consider a class of theories containing power-law terms in both the Ricci scalar and a scalar field, including their non-minimal couplings. As a first step, we systematically classify all non-trivial cases with a propagating scalar field that arise from the simplest general power-law formulation, which contains the minimal number of terms. We then analyze each case in detail, focusing on the structure of the degrees of freedom, by both formulating the theories in the Einstein frames and focusing on the singular points in the Jordan frame. We demonstrate that such theories can give rise to different, and sometimes unexpected structure of the modes, that can change at the leading order depending on the background.

Eduardo Traversi de Cai Conrado, Rosmeri Porfírio da Rocha, Michelle Simões Reboita et al.

Since the beginning of the satellite era, only three tropical cyclones have been recorded over the South Atlantic Ocean. To investigate the potential occurrence of such systems since the 1900s, ERA20C, a centennial reanalysis, was utilised. This study first evaluates the performance of ERA20C in reproducing the climatology of all cyclone types over the southwestern South Atlantic Ocean by comparing it with a modern reanalysis (ERA5) for the period 1979–2010. Despite its simpler construction, ERA20C is able to reproduce key climatological features, such as frequency, location, seasonality, intensity, and thermal structure of cyclones similar to ERA5. Then, the Cyclone Phase Space (CPS) methodology was applied to determine the thermal structure at each time step for every cyclone between 1900 and 2010 in ERA20C. The cyclones were then categorised into different types (extratropical, subtropical, and tropical), and systems exhibiting a warm core at their initial time step were classified as tropical cyclogenesis. Between 1900 and 2010, 96 cases of tropical cyclogenesis were identified over the South Atlantic. Additionally, throughout the lifetime of all cyclones, a total of 1838 time steps exhibited a tropical structure, indicating that cyclones can acquire a warm core at different stages of their lifecycle. The coasts of southeastern and southern sectors of northeast Brazil emerged as the most favourable for cyclones with tropical structures during their lifecycle. The findings of this study highlight the occurrence of tropical cyclones in the South Atlantic prior to the satellite era, providing a foundation for future research into the physical mechanisms that enabled these events.

Daniël Boer, Chris A. Flett, Carlo Flore et al.

The physics case for quarkonium-production studies accessible at the US Electron Ion Collider is described.

M. Kozlov, M. Safronova, José R. Crespo López-Urrutia et al.

Electronic states of highly charged ions show magnified fine-structure, Lamb shift, and hyperfine effects making them sensitive probes of bound-state quantum electrodynamics and nuclear physics. Being also impervious to external perturbations renders them ideal candidates for precision spectroscopy and accurate clocks that could test physics beyond the standard model. This review discusses how a variety of ion species and transitions may optimally be used to target such new applications, and presents routes to handle them in the laboratory.