Horizon Mass Theorem

A new theorem for black holes is found. It is called the horizon mass theorem. The horizon mass is the mass which cannot escape from the horizon of a black hole. For all black holes: neutral, charged or rotating, the horizon mass is always twice the irreducible mass observed at infinity. Previous theorems on black holes are: 1. the singularity theorem, 2. the area theorem, 3. the uniqueness theorem, 4. the positive energy theorem. The horizon mass theorem is possibly the last general theorem for classical black holes. It is crucial for understanding Hawking radiation and for investigating processes occurring near the horizon.Comment: A new theorem for black holes is establishe

Coupling of Gravity to Matter via SO(3,2) Gauge Fields

We consider gravity from the quantum field theory point of view and introduce a natural way of coupling gravity to matter by following the gauge principle for particle interactions. The energy-momentum tensor for the matter fields is shown to be conserved and follows as a consequence of the dynamics in a spontaneously broken SO(3,2) gauge theory of gravity. All known interactions are described by the gauge principle at the microscopic level.Comment: 12 latex page

Rotational energy term in the empirical formula for the yrast energies in even-even nuclei

We show that part of the empirical formula describing the gross features of the measured yrast energies of the natural parity even multipole states for even-even nuclei can be related to the rotational energy of nuclei. When the first term of the empirical formula, $\alpha A^{-\gamma}$, is regarded as the otational energy, we can better understand the results of the previous analyses of the excitation energies. We show that the values of the parameters $\alpha$ and $\gamma$ newly obtained by considering the $\alpha A^{-\gamma}$ term as the rotational energy of a rigid rotor are remarkably consistent with those values extracted from the earlier `modified' $\chi^2$ analyses, in which we use the logarithms of the excitation energies in defining the `modified' $\chi^2$ values

Exactly Solvable Pairing Model Using an Extension of Richardson-Gaudin Approach

We introduce a new class of exactly solvable boson pairing models using the technique of Richardson and Gaudin. Analytical expressions for all energy eigenvalues and first few energy eigenstates are given. In addition, another solution to Gaudin's equation is also mentioned. A relation with the Calogero-Sutherland model is suggested.Comment: 9 pages of Latex. In the proceedings of Blueprints for the Nucleus: From First Principles to Collective Motion: A Festschrift in Honor of Professor Bruce Barrett, Istanbul, Turkey, 17-23 May 200

Magnetic field calculation for a 13 MeV PET cyclotron

A design study of the main magnet for a 13 MeV cyclotron has been carried out in a joint collaboration between the Korea Cancer Center Hospital (KCCH) and POSTECH. A maximum energy of 13 MeV has been chosen to produce radioisotopes such as /sup 18/F. There are four magnet sectors, each with radial-ridged shape. Maximum magnetic fields are 1.85 T and 0.48 T at hill and valley centers, respectively. The total size of the cyclotron is less than 2 m in diameter. The program TOSCA has been utilized for the field calculation and optimization. In this paper, we describe design parameters of the 13 MeV PET cyclotron, with emphasis on the magnetic field shape and the beam optics calculation. (3 refs)

A research on ICT standards management based on standards reusability analysis

Standards are those generally agreed through repetitive use. They also make products and services more reliable. Thus, when developing standards, one should at first be aware of what the market actually needs not what the developers and providers want. If not, unnecessary standards will eventually end up being unused and dismissed. In this sense, standards developed primarily based on users' point of view are much more reusable. As information and communication technology (ICT) being accelerated these days, the number of standardisation activities has been dramatically increased and a great number of group and international standards has been developed all over the world. Therefore, Standards Developing Organisations (SDOs) follow routine maintenance procedures on their developed standards in order to assure their quality. In this paper, the authors propose a methodology for managing developed standards to enhance standards reusability in terms of standards development, maintenance, and management