Applications of14C-AMS in biomedical sciences (Bio-14C-AMS)

Accelerator mass spectrometry (AMS) is an ultrasensitive measure for tracing¹⁴C labeled moleculesin vivo or detecting the biomarker for assessment of carcinogenesis. In this review, basic principles, wide applications and new progresses of¹⁴C-bio-AMS are presented. It has been a new advanced tool for measuring the adduction of biologcial molecules with xenobiotics, including carcinogens, drugs, agrochemicals, nicotine, etc. The successful applications have proven the effectiveness of AMS to assessing cancer risk, screening drug toxicity and studying nutrients uptake. In particular, AMS is characterized by measuring xenobiotics at very low dose levels relevant to human environmental exposure. It is sensitive and precise to an attomole (10⁻¹⁸ mole) or less of¹⁴C per mg carbon. Although it has some shortcomings, undoubtedly, AMS possesses an evident merit of high sensitivity and will have widespread applications in the biomedical sciences.     

提高"强光一号"驱动Z箍缩负载电流的研究

“强比一号”加速器是目前国内输出功率最大的一台组合式多用途高功率强流脉冲电子束加速器。在该加速器上开展高功率Z箍缩产生X射线的技术研究时,需要调整提高“强光一号”驱动电流。主要介绍提高“强光一号”加速器输出电流的理论与实验研究。建立了计算模拟加速器工作过程的电路模拟程序,并在模拟计算的指导下开展了大量的实验研究,在短路电感15nH真空负载上获得了脉冲前沿小于100ns,峰值约3．0MA的脉冲电流,在优化设计的Z箍缩负载上得到了脉冲前沿小于100ns,峰值约2．2MA的脉冲电流．     

Materials as activator of future global science and technology challenges

The aim of this statement is to give a contribution towards the future, where for all, materials are the driven force for the transformations we aim to reach and for which a global common house is imperative to be established, as the International Union of Materials Research Societies, IUMRS aims to be the central vehicle for such, aiming to boost innovation to its maxima, without compromising vital global principles of opening science to the world. This is consolidated by 4 main principles: Circular Economy; Trans disciplinarity; Horizontal cross cutting synergy (the introduced Metro Station concept); look always to the Big Picture and not to silos. This means that the traditional vertical thematic topics that were essential to define so far, the so-called road maps for something should be revisited and reconverted towards much larger horizontal scenarios.     

双级活塞推料离心机加速盘的优化设计

针对双级活塞推料离心机物料分配系统中的叶片式离心加速盘在使用过程中存在物料加速效果差、晶粒易破碎等问题,借鉴泵等旋转机械中的叶片设计理论,对离心加速盘叶片曲线进行了优化设计研究．采用CFD数值模拟方法,对叶片曲线为等变角螺旋线和可控包角曲线两种离心加速盘的结构分别进行了计算,得到了物料在离心加速盘中运动的流场图．所选取的中径处径向速度和出口处切向速度能定性地反映物料在离心加速盘中的回流情况和加速效果．模拟计算结果表明,出口安放角为15°、包角为90°的可控包角曲线对重碱二次脱水最有利．将工业试验数据与模拟结果进行对比表明,试验与模拟结果相一致．本研究结果为双级活塞推料离心机在重碱生产中的应用提供了设计依据和指导．     

探究物质最深层次的物理规律：中国粒子物理发展规划的思考

 粒子物理是物质结构探索和研究的前沿学科,研究意义重大,成果影响深远,技术溢出效益明显。分析了粒子物理的研究目标及方法、特点,概述了中国粒子物理的基础、成就以及与国际领先水平的差距,探讨了中国粒子物理的未来发展目标、规划以及应采取的相关措施和应该发展的核心技术,提出了中国粒子物理向世界领先水平发展的建议。     

FPGA加速部件求解FMM算法中PP问题研究

提出了一种基于FMM求解多体问题的PP计算在FPGA加速部件上进行计算加速的实现方法.通过在对FMM算法中PP计算过程的原代码的计算类型分析与代码转化,给出了在FPGA上的具体实现方案,最后,通过Virtex-5实验平台的计算结果表明能够取得20倍左右的稳定加速效果.     

Regional Δ<Superscript>14</Superscript>C patterns and fossil fuel derived CO<Subscript>2</Subscript> distribution in the Beijing area using annual plants

The level of atmosphericΔ14C and the fossil fuel derived CO 2 concentration in the Beijing area from May to September,2009, were systematically analyzed based on radiocarbon(14C)measurements of annual plants by accelerator mass spectrometry(AMS). The results show that the maximumΔ14C in Beijing was 29.6‰±2.2‰,and the minimum was–28.2‰±2.5‰,with a trend of decreasingΔ14C from the outer suburbs to inner suburbs to the urban center.This trend correlates well with increases in fossil fuel derived CO2 caused by human activities such as population density,industrial emissions and traffic,with lower values of atmosphericΔ14C associated with more intensive human activities.The fossil fuel derived CO 2 concentrations from May to September, 2009,ranged from 3.9±1.0 ppm to 25.4±1.0 ppm.It was calculated that each additional 1 ppm of CO2 from fossil fuels depleted the atmosphericΔ14C by approximately 2.70‰.This study suggests that 14C measurements of annual plants by AMS provide an effective method to rapidly trace fossil fuel derived CO2.     

用 TMS320C5X 评价模块实现的 PC 运算加速器

在分析ＴＭＳ３２０Ｃ５Ｘ评价模块基本性能的基础上，提出了一种利用该评价模块（ＥＶＭ）实现ＰＣ运算加速器的思想和方法．以矩阵运算为例演示了运算加速的过程：将两个矩阵从ＰＣ机传送到ＥＶＭ；ＥＶＭ进行高速矩阵相乘，并将结果送回ＰＣ机．实验结果显示在高维数矩阵运算中，采用本文的方法可使信息处理的时间大为缩短，ＥＶＭ所需时间仅为原ＰＣ机的１／１０～１／５，对于处理大容量图形信息过程具有较高的应用价值．同时，对微机中央处理器的设计也具有参考价值．     

聚苯乙烯量热计的研制及其应用

为测量３￣５ＭｅＶ电子束的吸收剂量，研制了一台聚苯乙烯量热计，并实现了计算机控制的在线测量，不仅可以简单，快速，可靠地测量电子束吸收剂量，而且可以作为标准剂量计刻度传递剂量计和工作剂量计。     

MeTHPA对促进剂DMP—30的不变色试验研究

本文设计了四种实验方案，进行了McTHPA对促进剂DMP－30的不变色研究，并探讨了不变色（或稍变色）的最佳工艺条件．