SU(1, 3) as a Dynamical Group; Analysis of All the Discrete Representations

1973 ◽  
Vol 51 (14) ◽  
pp. 1573-1576 ◽  
Author(s):  
C. S. Kalman

A method using the most degenerate representation of SU(1, 3) as a dynamical group for the strong interactions of the spin 1/2+ baryons is extended to consider all the discrete representations. It is shown that physical conditions place very severe restrictions on the parameters characterizing such a representation.

1977 ◽  
Vol 55 (7-8) ◽  
pp. 673-676 ◽  
Author(s):  
C. S. Kalman

A method using SU(1,3) as a dynamical group for the baryons is extended to SU(1,4) by inclusion of the charm symmetry group SU(4) as maximum kinematic group. Several new mass formulae are given and the masses of the charmed baryons are predicted.


1977 ◽  
Vol 36 ◽  
pp. 143-180 ◽  
Author(s):  
J.O. Stenflo

It is well-known that solar activity is basically caused by the Interaction of magnetic fields with convection and solar rotation, resulting in a great variety of dynamic phenomena, like flares, surges, sunspots, prominences, etc. Many conferences have been devoted to solar activity, including the role of magnetic fields. Similar attention has not been paid to the role of magnetic fields for the overall dynamics and energy balance of the solar atmosphere, related to the general problem of chromospheric and coronal heating. To penetrate this problem we have to focus our attention more on the physical conditions in the ‘quiet’ regions than on the conspicuous phenomena in active regions.


Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada ◽  
J. Lehman

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.


Author(s):  
Kazuo Ishizuka

It is well known that taking into account spacial and temporal coherency of illumination as well as the wave aberration is important to interpret an image of a high-resolution electron microscope (HREM). This occues, because coherency of incident electrons restricts transmission of image information. Due to its large spherical and chromatic aberrations, the electron microscope requires higher coherency than the optical microscope. On an application of HREM for a strong scattering object, we have to estimate the contribution of the interference between the diffracted waves on an image formation. The contribution of each pair of diffracted waves may be properly represented by the transmission cross coefficients (TCC) between these waves. In this report, we will show an improved form of the TCC including second order derivatives, and compare it with the first order TCC.In the electron microscope the specimen is illuminated by quasi monochromatic electrons having a small range of illumination directions. Thus, the image intensity for each energy and each incident direction should be summed to give an intensity to be observed. However, this is a time consuming process, if the ranges of incident energy and/or illumination direction are large. To avoid this difficulty, we can use the TCC by assuming that a transmission function of the specimen does not depend on the incident beam direction. This is not always true, because dynamical scattering is important owing to strong interactions of electrons with the specimen. However, in the case of HREM, both the specimen thickness and the illumination angle should be small. Therefore we may neglect the dependency of the transmission function on the incident beam direction.


2020 ◽  
Vol 36 (5) ◽  
pp. 777-786 ◽  
Author(s):  
Julia Waldeyer ◽  
Jens Fleischer ◽  
Joachim Wirth ◽  
Detlev Leutner

Abstract. There is substantial evidence that students in higher education who have sophisticated resource-management skills are more successful in their studies. Nevertheless, research shows that students are often not adequately prepared to use resource-management strategies effectively. It is thus crucial to screen and identify students who are at risk of poor resource management (and consequently, reduced academic achievement) to provide them with appropriate support. For this purpose, we extend the validation of a situational-judgment-based instrument called Resource-Management Inventory (ReMI), which assesses resource-management competency (including knowledge of resource-management strategies and the self-reported ability to use this knowledge in learning situations). We evaluated the ReMI regarding factor structure, measurement invariance, and its impact on academic achievement in different study domains in a sample of German first-year students ( N = 380). The results confirm the five-factor structure that has been found in a previous study and indicate strong measurement invariance. Furthermore, taking cognitive covariates into account, the results confirm that the ReMI can predict students’ grades incrementally. Finally, a multi-group analysis shows that the findings can be generalized across different study domains. Overall, we provide evidence for a valid and efficient instrument for the assessment of resource-management competency in higher education.


1977 ◽  
Vol 38 (03) ◽  
pp. 0640-0651 ◽  
Author(s):  
B. V Chater ◽  
A. R Williams

SummaryPlatelets were found to aggregate spontaneously when exposed to ultrasound generated by a commercial therapeutic device. At a given frequency, aggregation was found to be a dose-related phenomenon, increasing intensities of ultrasound inducing more extensive and more rapid aggregation. At any single intensity, the extent aggregation was increased as the frequency of the applied ultrasound was decreased (from 3.0 to 0.75 MHz).Ultrasound-induced platelet aggregation was found to be related to overall platelet sensitivity to adenosine diphosphate. More sensitive platelets were found to aggregate spontaneously at lower intensities of sound, and also the maximum extent of aggregation was found to be greater. Examination of ultrasound-induced platelet aggregates by electron microscopy demonstrated that the platelets had undergone the release reaction.The observation that haemoglobin was released from erythrocytes in whole blood irradiated under identical physical conditions suggests that the platelets are being distrupted by ultrasonic cavitation (violent gas/bubble oscillation).It is postulated that overall platelet aggregation is the result of two distinct effects. Firstly, the direct action of ultrasonic cavitation disrupts a small proportion of the platelet population, resulting in the liberation of active substances. These substances produce aggregation, both directly and indirectly by inducing the physiological release reaction in adjacent undamaged platelets.


2020 ◽  
Vol 4 (1) ◽  
pp. 54-61
Author(s):  
Vinky Rahman ◽  
Muhammad Khairy Humaizy

The theater usually has an attractive form to attract the attention of visitors and also has good sound control in the auditorium so as not to cause sound distortion. Performances in Medan are still inadequate to accommodate international performances. Particularly in Medan, the enthusiasm of the community towards art tends to be high, but the facilities of the place lack to accommodate performances. Data collection methods are carried out by collecting primary data through a process of field comparative study and secondary data through literature studies & comparative studies. The design approach used in design studies are analyzing the physical, conditions around the site, potential, the limits that exist on the site, Site and environmental approaches are analysis of site conditions and the best solutions, the user approach is building analysis to meet the need for facilities and quality in accommodating the show, literature studies related to titles and themes and theories that support design ideas. The Metaphor is chosen as a truss design theme to convey the shape of building design by combining metaphorical forms of buildings and the prominence of the same metaphorical theme in the building to those who visit and see buildings to prevent sound distortions by using porous materials. Medan is a big city in Indonesia as a design area with consideration of a strategic location. It is expected that with the presence of this performance center, domestic and foreign tourists and especially Medan people themselves can enjoy the comfort and get to know traditional music and dance in Indonesia.


TAPPI Journal ◽  
2011 ◽  
Vol 10 (9) ◽  
pp. 17-23 ◽  
Author(s):  
ANNE RUTANEN ◽  
MARTTI TOIVAKKA

Coating color stability, as defined by changes in its solid particle fraction, is important for runnability, quality, and costs of a paper coating operation. This study sought to determine whether the size or density of particles is important in size segregation in a pigment coating process. We used a laboratory coater to study changes in coating color composition during coating operations. The results suggest that size segregation occurs for high and low density particles. Regardless of the particle density, the fine particle size fraction (<0.2 μm) was the most prone for depletion, causing an increase in the average size of the particles. Strong interactions between the fine particles and other components also were associated with a low depletion tendency of fine particles. A stable process and improved efficiency of fine particles and binders can be achieved by controlling the depletion of fine particles.


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