Isotope Effects of Solid Hydrogenic Pellet Ablation

The isotope effects of ablation processes in fusion plasma for five combinations of solid isotopic hydrogenic pellets H2, HD,D2,DT,and T2 have been studied for the first time to our knowledge.The results show that the modifications caused by isotope effects for pellet erosion speeds range from 1 for hydrogen pellet down to 0.487 for tritium pellet and are not negligible in ablation rate calculations.These effects can lead to deeper mass deposition and improved core fuelling efficiency.     

Off-line integration of CE and MALDI-MS using a closed-open-closed microchannel system

In this work, a new technique for off-line hyphenation between CE and MALDI-MS is presented. Two closed fused-silica capillaries were connected via a silicon chip comprising an open microcanal. The EOF in the system was evaluated using mesityloxide or leucine-enkephalin as a sample and with a running buffer that rendered the analyte neutrally charged. Comparison was made between the EOF in a closed system (first capillary solely included in the electrical circuit) and in a closed-open system (first capillary and microcanal included in the electrical circuit). It was concluded that the experimental values of the EOF agreed with the theory. The influence of the capillary outer diameter on the peak dispersion was investigated using a closed-open-closed system (first capillary, microcanal and second capillary included in the electrical circuit). It was clearly seen that a capillary with 375 microm od induced considerably higher peak dispersion than a 150 microm od capillary, due to a larger liquid dead volume in the connection between the first capillary outlet and the microcanal. Mass spectrometric analysis has also been performed following CE separation runs in a closed-open-closed system with cytochrome c and lysozyme as model proteins. It was demonstrated that a signal distribution profile of the separated analytes could be recorded over a 30 mm long microcanal.     

Clinical relevance of pressure-dependent scattering at low acoustic pressures

Recent optical and acoustical studies have shown a threshold behaviour in the response of phospholipid-coated contrast agents, for a certain range of sizes. Below the acoustic pressure threshold, the microbubbles’ scattering efficacy is significantly reduced compared to that above the threshold. Here we investigate the clinical relevance of the observed threshold behaviour. A cardiac ultrasound scanner system was used to analyse the pressure-dependence of the scatter intensity. The scattering of a native suspension of a phospholipid-coated contrast agent was compared to that of a suspension in which microbubbles with a size larger than 3.0 μm in diameter were extracted. A power modulation scheme at the fundamental frequency was applied. After linearly scaling and subtracting the B-mode images recorded at 70 and 200 kPa, the contrast-to-tissue ratio (CTR) of the native suspension was 3.2 dB, whereas the CTR of the filtered suspension was 20 dB. The 17 dB difference is attributed to the threshold behaviour. Well-established ultrasound imaging techniques such as fundamental power modulation imaging could benefit from the pressure-dependent scattering properties of this type of contrast microbubbles.     

D-~3He商用堆工作物理参数的空间分析

由于D-~3He聚变堆不要求厚的包层和大的内侧空间,中子壁负载小得多,第一壁几乎是永久性的,维修更换问题减轻。采用低径比有利于电流驱动和较大的等离子体变形和好的垂直稳定性,以便得到大的等离子体电流,因而得到高的β和好的约束。本文从目前普遍采用的堆芯等离子体物理规律为基础,编制了DHE3TOK程序。研究了以D-~3He为燃料,低径比A=2.5工作在第一稳定区的商用堆特点。对它的工作物理参数空间范围进行广泛调查的基础上,提出了需要研究和发展的关键工程技术问题。     

New Mechanism for Enhancing Ash Removal Efficiency and Reducing Tritium Inventory

A new mechanism is suggested to suppress ash particle back streams in the divertor region of our fusion experimental breeder （FEB） reactor for enhancing the ash removal efficiency and reducing the tritium inventory by applications of the nonlinear effect of high power rf ponderomotive force potential which reflects the platereleased and re-ionized He^＋ back to the plate. Meanwhile, the potential does not hinder α particles, which are coming from scraping of the layer, flowing to the target plate. However, it does stop tritium ions flowing to the target. Based on the FEB design parameters, our calculations have shown that the ash removal efficiency can be improved by as much as 40% if the parallel component of rf field 150-200 V/cm is applied to the location at a perpendicular distance L = 20 cm apart from the plate and the plate-recycling neutral helium atom energy is＇ about 0.75eV, at the same time, the tritium inventory can be reduced to some extent.     

FEB—E氚泄漏分析

由于氚本身非常昂贵而且氚的泄漏将造成环境污染,因此氚的控制对D－T加料的聚变堆来说是非常重要的问题。通常规定聚变堆环境周围总的氚泄漏率应＜3．7×10^11Bq·d^-1。在聚变实验增殖堆FEB－E设计中采用高压氦气冷却,液态锂作氚增殖剂,因而氚与增殖材料之间具有强的化学亲合力。在正常工作条件下,即温度低于680℃,由于氚的气相分压强很低,氚渗透泄漏几乎可以忽略不计,所以从包层泄漏极少。但是由于FEB－E氚燃耗率太低（2.08%),因而氚的通过量较大,氚泄漏主要发生在以下过程：从等离子体抽出气体的氚处理系统中（氢同位素低温分馏系统）漏失;氚从第一壁、偏滤器靶板渗透到氦气冷却剂,再由冷却剂工作流质的漏失导致氚的泄漏;氚植入和渗透到第一壁和偏滤器靶板材料及冷却剂管道内,再由这些部件的材料损坏、更换和报废过程中引起的氚漏失;从液态锂中提取氚的过程中氚增殖剂本身的直接损失引起的氚漏失;从等离子体加料系统（弹丸制作过程）的氚漏失。本文运用SWITRIM编码和Sieverts'定律,从氚在液态锂中的浓度以及溶解率常数随温度的变化关系中得到液态锂中氚的分压、再由氚压强的平方根（或一次幂）差定律计算氚向氦冷却剂中的泄漏,再假设一定的工作流失损失率,对FEB－E氚系统的氚泄漏进行分析,为环境安全评估提供必要的数据。在事故状态下的氚泄漏主要考虑当包层温度失控时氚从液态锂中析出向冷却剂渗透,再由于冷却剂工作流质的漏失导致氚的泄漏。     

混合堆FEB—E粒子抽除和氘氚回收系统的概要设计

实验混合堆FEB依靠偏滤器排出粒子及其携带的能量。排出的粒子包括聚变反应产物α粒子、等离子体表面相互作用产物杂质以及没能产生聚变反应的氘氚燃料粒子等。FEB－E粒子抽除和燃料回收循环系统的任务是抽除上述氦灰、杂质以及大量的没能产生聚变反应的氘氚燃料粒子等燃烧废气,以能实现有效的堆芯等离子体纯度控制和密度控制;同时将排出废气中没能产生聚变反应的氘氚燃料粒子分离、纯化和回收,即实现氘氚工艺处理。     

Wall deactivation with fluorosurfactants for capillary electrophoretic analysis of biomolecules

This paper describes the use of fluorosurfactants as buffer additives for capillary electrophoretic separation of proteins and peptides. Due to fluorosurfactant bilayer formation at the capillary inner wall, the surface charge can be adjusted and even reversed. If the running buffer pH is kept at a level where the proteins have the same sign of charge as the wall, electrostatic repulsion will be obtained. The protein wall adsorption can therefore be reduced and the separation performance can be noticeably increased. The separation performance can also be further improved by including mixtures of different types of fluorosurfactants in the running buffer. The buffer system can accordingly be adapted for a certain separation problem. Mechanisms for the use of fluorosurfactants for wall deactivation in capillary electrophoretic protein separations is discussed in the present work and some examples of applications are also presented.