Mode competition in a high harmonic gyrotron

Non-linear theory is used to examine the limits on the maximum power that might be obtained from a high harmonic gyrotron. In particular, special attention is paid to the situation where the power is limited by mode competition from a nearby fundamental resonance. We find good qualitative agreement between theory and some observations made on a high harmonic gyrotron at Fukui University.     

Focused ion beam-scanning electron microscope: exploring large volumes of atherosclerotic tissue

Atherogenesis is a pathological condition in which changes in the ultrastructure and in the localization of proteins occur within the vasculature during all stages of the disease. To gain insight in those changes, high-resolution imaging is necessary. Some of these changes will only be present in a small number of cells, positioned in a 'sea' of non-affected cells. To localize this relatively small number of cells, there is a need to first navigate through a large area of the sample and subsequently zoom in onto the area of interest. This approach enables the study of specific cells within their in vivo environment and enables the study of (possible) interactions of these cells with their surrounding cells/environment. The study of a sample in a correlative way using light and electron microscopy is a promising approach to achieve this; however, it is very laborious and additional ultrastructural techniques might be very valuable to find the places of interest.
In this report we show that the focused ion beam-scanning electron microscope is a powerful tool to study biological specimens in a correlative way. With this microscope one can scan for the area of interest at low magnification, in this case the atherosclerotic plaque, and subsequently zoom in, for further analysis on an ultrastructural level, rendering valuable and detailed two- and three-dimensional information of, in this case, the endothelial cells and the vessel wall. Moreover, in combination with pre-embedment labelling of surface exposed antigens, the method allows insight into the 3D distribution of these markers.     

基于商用坐标测量机的3D微纳米计量

以测量精度为1μm的商用坐标测量机（CMM）为基础,构建了测量范围为25mm×40mm×25mm、测量不确定度约为O．15μm的PTB微纳米专用坐标测量机．研究了CMM的运动控制系统、恒温室的空调系统以及CMM的被动隔振系统等对测量结果的影响．由测量结果可以看出,CMM的运动控制系统产生的噪声水平约为其他误差源的2倍．通过FFT运算,发现未优化系统的短时最大漂移量发生频率为750Hz,对应为运动控制的工作频率．文中还介绍了测量力为1州光纤探针的测量原理,并给出了对2．5mm短轴的测量结果．     

Ascorbic Acid and 5-Methyltetrahyclrofolate Losses in Vegetables with Cook/Chill or Cook/Hot-Hold Foodservice Systems

The percent retention of vitamin C and 5-methyltetrahydrofolate in seven cooked vegetables was analyzed using HPLC and compared in simulated cook/chill vs cook/hot-hold hospital foodservices. Retention of vitamins after conduction and infra-red reheating was investigated. Vegetables reheated after one day of chilled storage had greater losses of both vitamins compared to those held at 72°C for 30 min, but better vitamin retention than vegetables held hot 2 hr. There was no significant difference in nutrient retention due to method of reheating. If warm-holding is restricted to < 90 min, vitamin retention in vegetables is likely to be higher in a cook/hot-hold foodservice than with a cook/chill system.     

Bioactive amines changes in raw and sterilised milk inoculated with Pseudomonas fluorescens stored at different temperatures

The presence of bioactive amines in raw and sterilised milk inoculated with Pseudomonas fluorescens during storage at 4°C, 7°C and 10°C for 6 days was investigated. Spermine, spermidine, putrescine, serotonin and phenylethylamine were present in the samples immediately after milking. Histamine, cadaverine and tyramine were formed in the raw milk on the 4th day of storage at 10°C, increasing significantly afterwards. Cadaverine was formed during sterilisation. There was no significant change in amines, acidity, thermostability and alizarol tests throughout storage of the sterilised milk; however, a putrid smell was detected at every temperature on the 6th day. Therefore, raw or sterilised milk storage at 4–7°C should not exceed 4 days. Furthermore, raw milk should not be stored at 10°C.     

Measuring the frequency sweeping rate (dθn/dn) of a chirp signal

A circuit has been designed to estimate the rate of frequency change (dθ_n/dn) of a chirp signal. The novelty of this approach is that it presents a simple method for estimating a time varying input frequency totally derived from a first-order adaptive linear predictor technique rather than from a correlation based method. The simulation results confirm the theoretical analysis and show the potential of the new system in a noisy environment.     

Application of the dual-beam FIB/SEM to metals research

The dual‐beam microscope is a combination of a focused ion beam with an electron beam. The instrument used in this work is also equipped with an energy‐dispersive X‐ray system for local elemental analysis. This powerful tool gives access to specific features inside a material. Two different applications are presented in this paper: (1) cross‐sections and transmission electron microscope specimens cut in order to investigate the interface between an aluminium substrate and its epoxy coating; and (2) a grain boundary in a Cu₃Au alloy. In both cases, the dual beam succeeded where other methods failed.     

Focusing of high power millimeter-wave radiation by a quasi-optical antenna system

The focusing of millimeter-wave radiation from a high power 60 GHz gyrotron is studied using a two-dimensional ellipso-parabolic focusing antenna system. Fine focusing with an elliptic reflector gives a sheet beam of about 10 mm in thickness even at a high power input of about 100 kW. The addition of a parabolic reflector produces a finely focused and nearly Gaussian beam of about 10 mm in diameter with an energy density higher than lOOkWcm^-2. Spatial distributions of beam power are compared with calculations and good agreement is obtained.