An Injection and Acceleration System of a Pulsed Race-Track Microtron

A pulsed race-track microtron (RTM) with a maximum beam energy of 70 MeV [1] is described. This device was developed at the Research Institute of Nuclear Physics of Moscow State University (Russia) in cooperation with World Physics Technologies Inc. (USA). For this project, several new elements, including bending magnets (based on rare-earth permanent magnets) [2], a system for injection of the bunched electron beam through a compact -magnet (also based on permanent magnets [3]), and a rectangular cavity biperiodic structure (RCBS) [4, 5], were developed. Unlike axially symmetric accelerating structures, the RCBS has small transverse dimensions and, as a result, does not present an obstacle for the electron beam traveling in the first orbit. Moreover, the RCBS possesses a quadrupole focusing with the value and sign of the focal power depending on the relationship between the size of the drift aperture and the dimensions of the microtron cavity and on the phase of the microwave field. These properties substantially simplify the RTM design and tuning. Tests, the tuning procedure, and measured characteristics of the injection and acceleration systems of the race-track microtron are described.     

Preparation and optical properties of Co-doped ZnSe single crystals

ZnSe single crystals doped via Co diffusion are investigated. The diffusion was carried out from metal Co in He or Ar atmosphere. The spectra of optical density in the wavelength range 0.4–2 μm are investigated. It is found that the absorption edge shifts as the concentration of doping impurities increases. This shift is caused by the formation of the Zn_{1 ? x} Co_xSe alloy. The diffusion profile of the Co dopant is determined via measurement of the relative optical density of the crystals in the visible spectral region. The Co diffusivities (D) in the ZnSe crystals at T = 1103–1273 K are calculated. The analysis of the temperature dependence D(T) made it possible to determine the coefficients in the Arrhenius equation, namely, D ₀ = 3.4 × 10⁶ cm²/s and E ₀ = 3.8 eV.     

铜电镀和钻化学镀沉积的监测

最新的研究将CVS监测技术扩展到分析有机破坏性产品中。本文讨论了用一种光谱分析技术代替电位滴定法可以不使用试剂就能对铜进行分析的方法。化学镀沉积槽的在线控制也在本文中被提到。     

Transmission of hepatitis B to chimpanzees by hepatitis B surface antigen-positive saliva and semen

To assess the infectivity of hepatitis B surface antigen (HBsAg)-containing body fluids other than blood, chimpanzees were inoculated intravenously with saliva and semen obtained from HBsAg-positive individuals implicated in non-percutaneous transmission of hepatitis B. Saliva and semen samples were negative for occult blood. The titer of HBsAg in saliva was on the average only 1/3,000 that of the corresponding serum. One chimpanzee, inoculated sequentially with saliva from three individuals, developed HBsAg at 9 weeks and serum glutamic pyruvic transaminase elevation at 13 weeks after injection. HBsAg persisted for 15 weeks. This animal also developed e antigen, anti-core antibody, and anti-surface antibody. Liver biopsies showed acute hepatitis that subsequently resolved. A second chimpanzee, inoculated with HBsAg-positive semen, developed HBsAg and elevated serum glutamic pyruvic transaminase 4 weeks after inoculation and then died suddenly without explanation. HBsAg was positive in two consecutive samples and was confirmed by specific neutralization. Autopsy did not reveal evidence of hepatitis. This study demonstrates that HBsAg-positive saliva and, probably, semen contain infectious virus and suggests that saliva and/or semen may serve as important mechanisms in the transmission of type B hepatitis.