decay

摘要： Age-dependent Radiation Dose Rates from Canine Sn-117m Treatments Matthew G.Arno1,Chad Smith2(1.Foxfire Scientific,Arlington,TX;2.FX Masse,Gloucester,MA)Abstract:Tin-117m(Sn-117m)is used to treat dogs with osteoarthritic joints by radiosynoviorthesis.The decay process for Sn-117m is internal conversion wherein IC electrons and auger electrons provide the therapeutic effect.Additionally,the most prominent gamma emission is 158.6 keV.The effective dose rate received by a person interacting at close distances with a treated dog is needed to determine the person’s total dose and thus regulatory compliance.Simple measurement of the dose rate at a given distance does not provide an accurate measurement of the effective dose to a person due to the non-uniform nature of the radiation field at close distances.MNCP models of the interactions of five ages of humans at three distances were created to determine the effective dose rates using the methodology from NRC Regulatory Guide 8.40.Ratios of the effective dose rate to the person to the measured dose rate at 1 m from the same source were calculated.

摘要： Mud bricks were made in Egypt from the Nile silt, which is a mixture of clay and sand, which is sometimes mixed with pieces of organic materials and then mixed with water to make mud bricks, the oldest mud bricks were found in tombs dating back to Naqada and in Abydos, and parts of the central state pyramids were built from it, geological study and hydrogeology of the site were studied, mud bricks were studied by XRD and SEM, the main components and properties were studied, the mud bricks were made according to a local technique in industry and construction, the walls of Karnak temple become weak fragile materials due to their exposure to various damaging factors, the study put a recommended treatment of damaged mud bricks walls which surrounded of Karnak temple.

摘要： Electron spin resonance techniques were employed to investigate the effects of the absorbed dose and post-irradiation conditions on the evolution and decay of free-radicals in cross-linked polytetrafluoroethylene(XPTFE),induced byγ-ray radiation.Chain-end free-radicals,chain alkyl free-radicals,and tertiary alkyl free-radicals were detected when XPTFE was irradiated under Ar atmosphere.The corresponding peroxy free-radicals were formed upon exposure of irradiated XPTFE to air;the freeradicals concentration first increased linearly with increasing absorbed dose and then gradually saturated.The free-radicals yield under air atmosphere was greater than that under Ar,and the peroxy free-radicals were preserved for a relatively long time when irradiated XPTFE was stored under air atmosphere.The chain alkyl free-radicals may be converted to chain end free-radicals byβ-scission,while chain end free-radicals are more sensitive to oxygen than chain alkyl free-radicals.When the annealing temperature was raised above the a-transition temperature of XPTFE,the decay of the free-radicals was greatly affected and accelerated by the motion of the molecules over the long range.

摘要： Pomegranate fruit(cv.Wonderful)were treated with putrescine(1,2 and 3 mmol/L)before storage for 4 months at 5°C and 95%RH and the effects on postharvest life and quality attributes were studied.Results showed that incidence of physiological disorders such as external decay,husk scald,chilling injury and aril browning increased with progressive storage but treating pomegranate fruit with putrescine reduced incidence of most disorders.Control fruit had higher levels of external decay(1.72%–33.26%),chilling injury(10.53%–38.77%)and scalding(15.04%–100%)with less attractive color during 4 month storage.Variations were observed on other fruit quality parameters although treatment with putrescine at 2 and 3 mmol/L concentration reduced changes in color,total soluble solid,Titratable acidity and ascorbic acid.Sensory parameters were best preserved in fruit treated with 2 mmol/L concentration of putrescine with respect to juiciness and crispness.Treatment of pomegranate fruit with putrescine resulted in improved storability and fruit quality during storage.Therefore,for short term storage,2 mmol/L concentration of putrescine could be recommended for maintaining fruit quality especially in the first two months of storage.However,for longer storage period,a higher concentration is recommended,as 3 mmol/L concentration was the most effective in alleviating disorders and maintaining physico-chemical parameters and sensory attributes during storage in this study.

摘要： In this paper, we study a semilinear Timoshenko system with heat conduction having two damping effects. The observation that two damping effects might lead to smaller decay rates for solutions in comparison to one damping effect is rigorously proved here in providing optimality results. Moreover, the global well-posedness for small data is presented.

摘要： In this short review,we discuss a few recent advances in calculating the nonradiative decay rates for point defects in semiconductors.We briefly review the debates and connections of using different formalisms to calculate the multi-phonon processes.We connect Dr.Huang's formula with Marcus theory formula in the high temperature limit,and point out that Huang's formula provide an analytical expression for the phonon induced electron coupling constant in the Marcus theory formula.We also discussed the validity of 1D formula in dealing with the electron transition processes,and practical ways to correct the anharmonic effects.

摘要： In this work we re-examine a model of the nucleons that involve the weak interaction which was once considered by Heisenberg;that is a neutron may have the structure of a dwarf hydrogen-like atom. We formulate a quantum dynamics for the Heisenberg model of the neutron associated with interaction that involves the beta decay in terms of a mixed Coulomb-Yukawa potential and the More General Exponential Screened Coulomb Potential (MGESCP), which has been studied and applied to various fields of physics. We show that all the components that form the MGESCP potential can be derived from a general system of linear first order partial differential equations similar to Dirac relativistic equation in quantum mechanics. There are many interesting features that emerge from the MGESCP potential, such as the MGESCP potential can be reduced to the potential that has been proposed to describe the interaction between the quarks for strong force in particle physics, and the energy spectrum of the bound states of the dwarf hydrogen-like atom is continuous with respect to distance. This result leads to an unexpected implication that a proton and an electron may also interact strongly at short distances. We also show that the Yukawa potential when restrained can generate and determine the mathematical structures of fundamental particles associated with the strong and weak fields.

摘要： In this work,a Timoshenko system of type Ⅲ of thermoelasticity with frictional versus viscoelastic under Dirichlet-Dirichlet-Neumann boundary conditions was considered.By exploiting energy method to produce a suitable Lyapunov functional,we establish the global existence and exponential decay of type-Ⅲ case.