Transverse phase space reconstruction study in Shanghai soft X-ray FEL facility

Phase space is one of the most important parameters used to describe beam properties. Computer tomography, as a method for reconstructing phase space and measuring beam emittance, has been used in many accelerators over the past few decades. In this paper, we demonstrate a transverse phase space reconstruction study in the Shanghai soft X-ray free electron laser facility. First,we discuss the basic principles of phase space reconstruction and the advantage of reconstructing beam distribution in normalized phase space. Then, the phase space reconstruction results by different computer tomography methods based on the maximum entropy(MENT) algorithm and the filtered back projection algorithm in normalized phase space are presented. The simulation results indicate that,with proper configuration of the phase advance between adjacent screens, the MENT algorithm is feasible and has good efficiency. The beam emittance and Twiss parameters are also calculated using the reconstructed phase space.     

FCM燃料堆内行为模拟及结构设计研究

本文采用二维特征模型模拟不同无燃料区厚度全陶瓷微封装弥散(FCM)燃料的热力学行为,在保证堆芯装载要求的条件下,研究不同结构FCM燃料SiC基体和包覆燃料颗粒SiC层的应力状态。通过优化无燃料区厚度,调整TRISO颗粒间的间距,保证无燃料区和SiC层同时具有较低的应力水平。分析了无燃料区厚度为100～500μm时基体SiC、无燃料区以及SiC层的应力分布,结果表明,基体SiC和SiC层最大应力随无燃料区厚度增大而增大,而无燃料区的最大应力则随其厚度增大而降低。当无燃料区厚度为400μm时,无燃料区和SiC层均处于较低的应力状态,无燃料区SiC基体应力约为400 MPa,而SiC层的最大环向应力约为200MPa,其失效概率约为2.5×10-4。因此,当无燃料区厚度为400μm时,FCM燃料既能维持芯块结构完整,又能保证SiC层具有较低的失效概率。结构优化为FCM燃料的应用提供了基础。     

钻孔处置简介

介绍了钻孔处置概念及3个国家的钻孔处置设施。对于废放射源和少量放射性废物,钻孔处置将是一个安全、经济和有效的最终处置方案。     

野外试验场黄土的理化分析

本实验为低,中水平放射性废物浅地层处置安全评价提供现场土壤的物理化学参数。采样深度在０．５－９．１ｍ范围内,每个样品进行１０项测定;矿物组成,粒度分布、密度、总孔隙度、有效孔隙度、给水度、持水度、渗透系数、阳离子交换容量、含水量。     

快速心肌显像剂^99mTc—TEBO的标记和动物体内分布实验

报道了用＾９９ｍＴｃ标记Ｔｅｂｏｒｏｘｉｍｅ（简称ＴＥＢＯ），并在标记后对其质量进行了鉴定。结果表明，其物理性质、化学性质及生物学性质均符合国家制定的放射性药物的质量标准；动物实验表明，小鼠注射量为成人用量的１００倍、观察１５天后，实验组和对照组无差别；注入量为０．１ｍｌ（２０７．２Ｂｑ／只），２ｍｉｎ后心肌摄取达峰值１７．７５±０．３３％（ｇ ｏｒｇａｎ）＾－１；心肌清除也快，１５ｍｉｎ已清除至     

镭厂退役废物分类与处理处置

由于镭厂退役废物的多样性,多必须适当分类后才能分别进行处理处置。利用现有条件,将含镭低放废物进行废铀矿井处置是合理,安全和经济的。     

应用MARSSIM方法对原核工业国营二二一厂退役场址进行辐射环境后评价

本文依据MARSS瑚提出的方法对原核工业国营二二一厂退役场址进行了退役后十年辐射环境状况评价。结果表明：原二二一厂场址区的退役是符合验收标准的,并且退役十年后的辐射环境状况也无明显变化。文中对非参数统计方法和抬升测量比较方法在大面积污染场地监测与评估中如何应用及应用的效果进行了简要的介绍。实践表明,MARSS瑚提出的非参数统计方法和抬升测量比较方法简单实用,对我国即将面临的核设施退役,特别是在大面积放射性污染场地的监测与评估中,具有实际意义。     

Stable Organic Titanium Catalysts and Reactive Distillation Used for the Transesterification of Dimethyl Carbonate with Phenol

The transesterification of dimethyl carbonate with phenol to methyl phenyl carbonate (MPC) was investigated on novel catalysts such as titanium diisopropoxide bis(ethyl acetoacetate) and titanium dibutoxide bis(ethyl acetoacetate) in a closed batch reactor at 185–206 °C under high pressure. The produced methanol could be removed efficiently by reactive distillation in order to overcome the equilibrium. The prepared catalysts have higher resistance to water than titanium alkoxides. Phenol conversion as high as 86.4 % with an MPC selectivity of 99.4 % was achieved under optimal reaction conditions within 9 h. Most of the catalytic activity was retained after repeated use for ten times.     

基于路面变形控制标准的综合管廊穿越高速公路的安全评估

以北京新机场临空经济区综合管廊穿越京开高速工程为背景,采用数值分析的方法模拟施工全过程,通过计算综合管廊第1层及第2层穿越高速公路时的路面变形值,总结高速公路路面变形规律并提出变形控制值,以确保综合管廊的安全施工,为后续类似工程提供依据和参考。     

Prevention of breast cancer by dietary polyphenols—role of cancer stem cells

Abstract

Breast cancer is a common malignancy with poor prognosis. Cancer cells are heterogeneous and cancer stem cells (CSCs) are primarily responsible for tumor relapse, treatment-resistance and metastasis, so for breast cancer stem cells (BCSCs). Diets are known to be associated with carcinogenesis. Food-derived polyphenols are able to attenuate the formation and virulence of BCSCs, implying that these compounds and their analogs might be promising agents for preventing breast cancer. In the present review, we summarized the origin and surface markers of BCSCs and possible mechanisms responsible for the inhibitory effects of polyphenols on BCSCs. The suppressive effects of common dietary polyphenols against BCSCs, such as curcumin, epigallocatechin gallate (EGCG) and related polyphenolic compounds were further discussed.