Biological characteristics of [~(18)F]-THK523 for tau imaging

Reliable and non-invasive diagnostic tools are highly valuable for successful therapeutic strategies for the treatment of Alzheimer's disease(AD). The existence of neurofibrillary tangles(NFTs) consisting of tau protein are one kind of the pathological features of AD, and its level of severity is correlated with the stage of AD.However, no clinically approved positron emission tomography(PET) probe is currently available for selective imaging of neurofibrillary tangles on patients. In this paper, we report our studies on biological characteristics of [18F]-THK523 as a novel tau imaging probe. With low molecular weight, [18F]-THK523 is stable, electrically neutral, lipophilic and non-mass concentration-dependent. Preliminary biological studies have shown the excellent properties of [18F]-THK523 as brain imaging tracer for further research.     

Accurate Volume Measurement System for Plutonium Nitrate Solution

Abstract

An accurate volume measurement system for a large amount of plutonium nitrate solution stored in a reprocessing or a conversion plant has been developed at the Plutonium Conversion Development Facility (PCDF) in the Power Reactor and Nuclear Fuel Development Corp. (PNC) Tokai Works. A pair of differential digital quartz pressure transducers is utilized in the volume measurement system. To obtain high accuracy, it is important that the non-linearity of the transducer is minimized within the measurement range, the zero point is stabilized, and the damping property of the pneumatic line is designed to minimize pressure oscillation. The accuracy of the pressure measurement can always be within 2 Pa with re-calibration once a year. In the PCDF, the overall uncertainty of the volume measurement has been evaluated to be within 0.2%. This system has been successfully applied to the Japanese government's and IAEA's routine inspection since 1984.     

Oxygen influenced intergranular crack propagation: analysing microstructure and chemistry in the crack tip region

Abstract

Ni-base superalloys have for decades been studied with regard to environmentally influenced intergranular crack propagation. For high temperature fatigue frequencies <0.1 Hz, it has been shown that an oxygen-rich environment promotes time-dependent crack growth while at >0.1 Hz and/or in inert environments (e.g. vacuum) crack growth is cycle dependent. Oxygen interaction at, or ahead of, the crack tip has been pointed out as the reason for the degraded mechanical properties. While many aspects of this type of crack growth have been previously investigated there is still no consensus about the detailed mechanisms, mainly due to the lack of in-detail investigations of the crack-tip region.

Here, crack tip regions in the Ni-base superalloy Alloy 718 were studied. Specimens were subjected to 90 s hold-times at 550°C and 650°C. Crack growth was arrested before final fracture, allowing cross-sectional analyses of the crack-tip region using scanning electron microscopy (SEM). Detailed studies of the crack-tip region were performed using transmission electron microscopy (TEM) and atom probe tomography (APT). For both APT and TEM samples, site-specific focussed ion beam (FIB) sample preparation was performed in a combined FIB-SEM system. The methodology of accessing and analysing the crack tip region is shown. Initial results on oxidation, oxygen penetration and plastic deformation are shown and discussed.     

DMA thermal analysis of different parts of potato tuber

Dynamic mechanical analysis (DMA) was applied to three potato tissues (‘cortex’, ‘pith’, and ‘side’ surface) of two cultivars (more waxy ‘Nicola’ and more mealy ‘Saturna’) in temperature scans in the range 30–90 °C and constant air humidity of 90%. The obtained scans indicate peaks in both storage and loss module of elasticity (SM and LM, respectively) at temperatures higher than 70 °C – so called ‘starch’ peak (SP) – as was observed previously. The peak value increase with increasing potato dry matter (DM) content, below DM content approximately 14% no SP is observed (‘Nicola pith’). Slope analysis of the basic parameters: SM, LM, and loss tangent (LT) was performed and further characteristic points on the temperature plots were found: (i) in temperature range A (30–40 °C) maximum of SM and LM and minimum of LT, (ii) in temperature range B (40–50 °C) minimum of SM and LM slopes corresponding to point of inflection on SM-T and LM-T plots, (iii) at about 50 °C, big peak in LT in side tissue only, (iv) at about 70 °C just prior the ‘starch’ peak, big peak in LT that is more marked in ‘pith’; this peak denoted as ‘I’ influenced the ‘starch’ peak ‘II’. It was found that both cultivar and part of the tuber influences the DMA temperature plots.     

Design and Fabrication of a Movable Langmuir Probe for Plasma Edge Parameters Measurement in the IR-T1 Tokamak

For the edge plasma parameters measurement, a movable Langmuir probe is fabricated and installed on the IR-T1 tokamak. The set-up consists of two sets of single Langmuir probes with tungsten tip movable in the radial direction. Edge plasma parameters including electron temperature, Ion density, floating potential and the corresponding radial changes are measured. Using two-point correlation technique clearly reveal that in the SOL region the poloidal propagation of floating potential fluctuation is in the direction of ion diamagnetic drift and in the edge it propagates in the electron diamagnetic drift direction.     

物理气相沉积中等离子体参数表征的研究进展

物理气相沉积作为制备表面防护薄膜的重要方法,一直是表面薄膜领域研究重点,而物理气相沉积中等离子体作为直接影响薄膜性能的关键因素,其参数的表征对优化沉积工艺和提高薄膜性能具有重要指导意义.概述了常用物理气相沉积方法及其发展,包括电弧离子镀、磁控溅射和电弧磁控复合技术的原理及发展历程.归纳了目前生产中常用的等离子体参数表征方法——Langmuir探针法、汤姆逊散射法、微波干涉法和发射光谱法,阐明了这些表征方法诊断等离子体参数的原理,分析了不同表征方法的优缺点和存在的主要问题,并对常用物理气相沉积中等离子体参数表征相关研究的发展和现状作了综合论述和总结,分别整理了电弧离子镀和磁控溅射中等离子体参数诊断的发展历程和近期研究.两种物理气相沉积方法最常用的等离子体参数表征方法都是Langmuir探针法和发射光谱法,早期的研究侧重于探索等离子体瞬态参数和薄膜结构性能的关系.随着现代技术的进步,早期诊断方法不断与新技术融合,研究方向也逐渐偏向于研究等离子体参数的时间变化和优化薄膜工艺、性能评价方法.最后分析了当前物理气相沉积中等离子体参数表征存在的问题和不足,展望了等离子体参数未来的研究趋势.     

基于1394b总线仿真设备的WDM驱动开发

基于解决1394b和PCI的跨速率条件下通信数据易丢失,软硬件交互产生误码的目的。本文采用WDM(波分复用)驱动的串行处理操作来保护硬件;采用内核态线程保证数据传输的确定性;采用DMA(直接内存存取)保证数据的实时性;采用循环队列的模式保证数据传输的可靠性;采用乒乓原理保证硬件和软件交互的准确性等。通过实验验证,该驱动程序实现了软硬件的协调工作、提高了软件对硬件操作的操作安全性、提高了传输数据的可靠性以及实时性等。     

基于光纤传感技术的伽马探测研究

利用Sol-gel法制作掺铈石英光纤的前驱体,采用powder-in-tube技术拉制掺铈光纤,分析闪烁光纤的影响因素,确定光纤传感器的结构和尺寸,研制出闪烁光纤传感器.闪烁光纤传感器对伽马射线具有发致发光效应,伽马射线与被记录光子算有对应关系,通过计算处理,得到伽马射线的强度.通过实验,实现闪烁光纤对伽马射线的探测,并能分辨出射线强度随距离变化的响应.通过与NaI晶体作为探测体进行对比,得知闪烁光纤传感器探测的技计数率相对比较低,距实际测井应用还有需要进一步研究.通过闪烁光纤传感技术能够实现对伽马射线的探测,对于实现光纤传感器对自然伽马射线探测具有重要的意义.     

高压直流GIL中盆式绝缘子表面电荷积聚与消散的实验研究

研究直流电压下绝缘子表面电荷积聚及其抑制措施,是开发直流气体绝缘管道输电线路(GIL)的一项关键技术。因此建立了一套盆式绝缘子表面电荷测量系统,采用静电探头法,在空气中对施加了直流电压后的环氧树脂盆式绝缘子进行了表面电位的测量,研究了不同极性、不同幅值电压以及极性反转情况下表面电荷的积聚现象,并对表面电荷的消散进行了测量。实验结果表明:绝缘子表面电荷分布与所施电压极性密切相关;在0.5 MPa空气中,随着施加电压幅值(+40~+70 kV)增加,绝缘子表面电荷急剧增加(负电位最大处从-200 V增加到-3 000 V);在0.5 MPa空气中,先后施加+70 kV及-40 kV电压,绝缘子局部表面电荷激增现象明显(正电位最大处由500 V增大到超过2 500 V);在0.1 MPa空气中施加+40 kV电压,在0~300 min内,绝缘子表面电荷消散近似指数衰减过程,时间常数约为104 s数量级。     

A probabilistic model for correcting the directional sensitivity of optical probe measurements

A probabilistic model is introduced for correcting the directional sensitivity of the optical probe technique routinely used to determine gas holdup and bubble dynamics in gas‐liquid systems. Measurements from optical probes oriented at various angles were collected from the tapered end of optical probes in regions where approximately unidirectional and bubbly flow conditions were observed. Based on logical assumptions, constitutive equations for a probabilistic model were formulated, and contributions to the overall local gas phase holdup from bubbles traveling in two opposite directions were quantified. The results demonstrate a novel and useful way to interpret optical probe measurements. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3516–3527, 2015