Comparison of microbiological loads and physicochemical properties of raw milk treated with single-/multiple-cycle high hydrostatic pressure and ultraviolet-C light

The effects of ultraviolet-C radiation (UV-C, 11.8?W/m²), single-cycle and multiple-cycle high hydrostatic pressure (HHP at 200, 400 or 600?MPa) on microbial load and physicochemical quality of raw milk were evaluated. Reductions of aerobic plate count (APC) and coliform count (CC) by HHP were more than 99.9% and 98.7%, respectively. Inactivation efficiency of microorganisms increased with pressure level. At the same pressure level, two-cycle treatments caused lower APC, but did not show CC differences compared with single-cycle treatments. Reductions of APC and CC by UV-C were somewhere between 200?MPa and 400/600?MPa. Both HHP and UV-C significantly decreased lightness and increased pH, but did not change soluble solids content and thiobarbituric acid-reactive substances’ values. Two 2.5?min cycles of HHP at 600?MPa caused minimum APC and CC, and maximum conductivity. Compared with HHP, UV-C markedly increased protein oxidation and reduced darkening.     

Design of Coupling Structure for MMW Folded Waveguide TWTs

A significant advantage of the folded wave traveling wave tube (TWT) is simple coupling structure. In millimeter wave band, owing to higher frequency, linear double taper can be used as impedance transformer. The design method and calculation results for the folded waveguide TWTs in K-band are given.     

Quantum Fluctuations in a Mesoscopic Inductance Coupling Circuit

Starting from the equation of motion of a mesoscopic inductance coupling circuit,the quantum fluctuations of charge and current in the circuit are investigated inboth the eigenstates of the system and the squeezed vacuum state. The resultsshow that there exist quantum fluctuations of the charge and current in bothcases, and the fluctuations in each component circuit are connected.     

筋骨草甾酮C的谱学特征

筋骨草甾酮C是分布于植物中的植物甾酮类化合物,具有抗氧化的作用.本文标定了该化合物中所有的碳信号,并通过¹³C-¹H COSY和¹H-¹H COSY技术纠正了文献中氢信号归属的错误.     

血卟啉单甲醚对DNA损伤的拉曼光谱研究

利用激光拉曼光谱技术研究了新型光敏剂血卟啉单甲醚对ＤＮＡ（脱氧核糖核酸）分子的光动力学损伤。结果表明：ＤＮＡ分子由典型Ｂ型构型变成了一种修饰过的Ｂ型。连接碱基对的氢键被部分打断,碱基堆叠也有所与解。碱基本身也遭到了破坏,有脱氨基现象发生。腺嘌呤和胞嘧啶对血咔啉单甲醚的光动力学损伤更敏感。