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[en] In this Letter we investigate a new integrable equation derived recently by Degasperis and Procesi. Analogous to the Camassa-Holm equation, this new equation possesses the blow-up phenomenon. Under the special structure of this equation, we establish sufficient conditions on the initial data to guarantee the formulation of a singularity in the sense that the derivative of the solution blows up in finite time. Moreover, a global existence result is found
[en] We have investigated the present renormalization prescriptions of Cabibbo-Kobayashi-Maskawa (CKM) matrix, and found there is still not an integrated prescription to all loop levels in the on-shell renormalization scheme. In this Letter we attempt proposing a new prescription designed for all loop levels in the present perturbative theory. This new prescription will keep the unitarity of the CKM matrix and make the amplitude of an arbitrary physical process involving quark mixing convergent and gauge independent
[en] Production and application of radioisotopes in China started almost thirty years ago. At present there are 20 units producing more than 700 radioisotope products. This report outlines the present status and prospect of radiation and radioisotopes in some major areas. Remarkable achievements have been made in agriculture using nuclear technology. More than 70 new varieties or strains of cultivated plants have been bred by inducing mutation through irradiation. A new variety of silkworm bred by irradiation has unique characteristics such as high and stable yield. Application of radioisotopes in medical research and clinical practice began in 1956 and radionuclides have been progressively used in diagnosis and treatment of diseases. The most common radionuclide used in therapy is iodine-131 for hyperthyroidism. Isotope-tracer technique and activation analysis play an important role in the study of traditional Chinese medicine. Isotope methods in China have been used in many industrial branches, such as textile, plastic and printing, but not very widely now. The nation has produced more than 2,000 sets of nuclear radiation measuring instruments, which become important parts of industrial automation control. The radiation processing research started in the end of 1950's. Food irradiation research has been going on in a good cooperation of different branches. Now China is planning to set up some plants to produce gamma irradiated disposal syringes and other medical devices. (Nogami, K.)
[en] The paper describes the real time computer control system used for monitoring and control parameters of the electron irradiation facility. The process control is achieved through the control system made up of a personal computer, three I/O boards and an ISA interface board. The improved bipartition transport theory has been applied to calculate the absorbed dose of low energy electron The experimental results proved that the dose control precision of the system has been greatly raised, and the other performance indexes have been obviously improved. This interlocking system may be used for dose monitoring and process control in EB radiation processing
[en] The key to the successful design of metal-organic coordination polymers is the judicious selection of organic ligand. Recently, polydentate aromatic nitrogen heterocyclic ligands with five-membered rings have been well-studied in the construction of supramolecular structure for their N-coordinated sites apt to coordinating to transition metals. Similar to six-membered N-heterocyclic ligands, the azole-based five-membered N-heterocyclic ligands, such as imidazoles, triazoles and tetrazoles have been extensively employed in the construction of various coordination polymers with diverse topologies and interesting properties. The bis(azole) ligands in which N-donor azole rings (imidazole, triazole, or tetrazole) are separated by alkyl, (CH2)n, spacers are good choices for flexible bridging ligands. The conformational flexibility of the spacers makes the ligands adaptable to various coordination networks with one-, two-, and three dimensional structures
[en] Intergranular corrosion (IGC) is observed on mild steel surface when the steel is polarized to passive potential zone in CO_2 + NaNO_2 solution. The methods of potentiodynamic polarization, scanning electron microscope (SEM) and scanning tunneling microscope (STM) are applied to study the phenomenon. Intergranular corrosion mainly happens as the steel is polarized into the active–passive transition zone, and the width and depth of the corroded grain boundaries increase with potential in the zone. When the potential enters the passive zone, the depth of IGC shows only very slight change. The IGC is related to the segregation of the impurity elements Mn and Si at the grain boundaries. The occurrence of intergranular corrosion is influenced by the potential scanning rate and CO_2 concentration in the solution. When the potential scanning rate is below 0.3 mV s"−"1 IGC phenomenon is observed. In saturated CO_2 + NaNO_2 solution no IGC is observed which may be attributed to the formation of FeCO_3 layer on steel surface that protects the grain boundaries from corrosion. The observed IGC is due to the combined effect of CO_2 and NaNO_2 in solution. NO_2"− promotes passivation on the grain surface but CO_2 induces corrosion at the grain boundaries
[en] Preparation of the monomer modified by phosphite is described. According to the results of IR, MS and 1H-NMR, the possible synthesis path was deduced. The coating was made up of polyurethane acrylate, modified monomer, active diluent and so on. A non-tacky transparent film can be obtained after EB curing in the air. The experiment indicated that the modified monomer plays a great role in resisting oxygen inhibition. Furthermore, it reduces the radiation dose that the curing needs, and takes effect on radiation sensitization. The optimum radiation condition is 40 KGy. The gel content was used to express the curing extent and the relationship between dose and P-H bond conversion was studied
[en] The KOALA experiment will measure antiproton-proton elastic scattering in a range of four-momentum transfer t from 0.0005 to 0.1 (GeV/c)2 at the upcoming HESR ring of FAIR. It aims to provide key input parameters for PANDA's absolute luminosity determination. KoalaSoft is the dedicated simulation software package for the KOALA experiment. It is develped based on FairRoot. Due to the flexibility of FairRoot, KoalaSoft combines the simulation, reconstruction and analysis tasks into one framework. The full geometry of KOALA setup is realized using the ROOT geometry package. Digitization of the Recoil Detector is also finished and the results are compared directly with the test beam data. The latest results are presented in this talk.
[en] The KOALA experiment will measure antiproton-proton elastic scattering cross-section in a wide range of four momentum transfer t from 0.0008 to 0.1 (GeV/c) at the upcoming HESR ring of FAIR. It aims to provide key input parameters for PANDA's luminosity determination. The recoil detector of KOALA has already been built and tested with proton beams by measuring proton-proton elastic scattering at COSY. The recoil detector measures both the kinetic energy and the polar angle of the recoil proton. The beam test results show that a range of t down to 0.001 (GeV/c) can be measured with the recoil detector alone. However, large background events from inelastic proton-proton reaction at polar angle close to 90° limit the ability of the recoil detector to reach all the way down to the lowest end of the required t range. To extend the lower limit, a forward scintillator detector has been built. The goal is to suppress the high background by the coincidence measurement between the recoil proton and the forward scattered beam particle. The scintillator bars are placed close to the beam axis covering the polar angle range of 0.4°-1.2°. Performance tests of the forward detector are carried out in the laboratory and the results will be reported in this talk. The commissioning of the full KOALA setup with proton beam at COSY is also described and the latest results will be presented.