Dosimetric Analyses of Single Particle Microbeam in Cell Irradiation Experiment

Single particle microbeam （SPM） is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism. This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.     

Purification and Properties of a New L-Sorbose Dehydrogenase Accelerative Protein from Bacillus megaterium Bred by Ion-Beam Implantation

Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbose dehydrogenase accelerative protein （SAP） to accelerate the activity of L-sorbose dehydrogenase （SDH） of Gluconobacter oxydans in the 2-keto-L-gulonic acid （2KLG） fermentation from L-sorbose by the mixed culture of B. megaterium BM302 and G. oxydans. The SAP purified by three chromatographic steps gave 35-fold purification with a yield of 13% and a specific activity of 5.21 units/mg protein. The molecular weight of the purified SAP was about 58 kDa. The SDH accelerative activity of SAP at pH 7 and 50℃ was the highest. Additionally, it retained 60% activity at a pH range of 6.5 ～ 10 and was stable at 20℃ ～ 60℃. After 0.32-unit SAP was added to the single cultured G. oxydans strains, the SDH activity was apparently accelerated and the 2KLG yield of GO29, GO112, GO and GI13 was enhanced 2.1, 3.3, 3.5 and 2.9 folds respectively over that of the strains without the addition of SAP.     

Analysis and Optimization of Stability of CAS-LIBB Single Ion Microbeam

Single ion microbeam is the most advanced technology which can emit a single ion for precise localization. A single-ion microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering （LIBB）, Chinese Academy of Sciences （CAS）, with a spatial resolutions of about 5 μm. Based on CAS-LIBB microbeam, three key elements affecting the quality of the system are assessed： the size of beam spot, the energy range and the counting accuracy of implanting ions. Various contributions to the ion beam stability, including the ion source, the terminal voltage of electrostatic accelerator and the components in beam pipeline, are discussed. Analysis shows that the improvement of terminal voltage stability is the most important issue for future optimization of CAS-LIBB facility. Some preliminary investigations and project aimed at optimization and development are proposed as well.     

基于RS-485总线的设备分布检测系统的研究

针对高校实验仪器设备维护与管理系统中存在的智能化、数字化程度不高和不便于远程控制等问题,本文介绍一种基于RS-485的电子设备检修系统的结构和实现方法.文中重点介绍系统结构、网络节点转换接口、网络通信协议及通信软件抗干扰措施的设计思路.实践表明,该系统具有可靠性高、通信速度快、抗干扰能力强等优点,有着广泛的应用前景.     

一种先进测试系统的分析与介绍

1 测试系统结构和功能 测试系统由信号输入、数据采集设备、计算机部分和软件系统等几部分组成。可通过对电量、热工量等多个测试量进行测量及监控。 1.1 信号输入部分 信号输入部分由传感器、变送器组成。传感器包括电量传感器和热工量传感器。电量传感器:电压互感器、电流互感器、分流器。热工量传感器:压力、流量、液位传感器、热电阻、热电偶。变送器进行信号的变换,所测电量若为高电压或大电流,必须变送成低电压或小电流后才能进入数采系统。虽然可使用普通互感器,但由于其次级可能产生高电压和大电流,会损害数采系统,故应采用隔离型…     

市政工程施工管理探讨分析

随着我国经济的不断发展,我国各个城市的市政工程建设也在不断的发展当中,各种市政工程建设和管理的新办法、新技术不断的涌现。本文就市政工程在施工管理方面的内容以及特点分析和对市政工程施工现场情况进行管理的状况分析方面对市政工程的施工管理进行了简要的探讨分析。     

基于性能模拟的地域气候适应型大型商业建筑设计研究——以哈尔滨华润·欢乐颂为例

文章基于建筑地域气候适应性设计理论,结合哈尔滨华润·欢乐颂的设计过程,以实现建筑空间环境舒适性与低能耗为目标,利用Phoenics与Ladybug Tools软件对场地的风环境、建筑能耗、室内自然采光情况、室内自然通风情况展开模拟分析,并通过选取单体块建筑形体、设置北侧气候缓冲空间、优化天窗形式等措施,降低建筑能耗,提升室内舒适性。     

高比表面积阿魏酸多孔淀粉酯结构表征及体外消化特性

为合成高比表面积阿魏酸多孔淀粉酯(ferulic acid porous starch ester, FA-PS),探索其结构特性及体外消化性能,丰富食品级活性物质吸附剂及功能性递送载体材料的种类,该研究以溶剂交换法制备的多孔淀粉(porous starch, PS)为主体,阿魏酸(ferulic acid, FA)为酯化剂,在非水相体系中制备了取代度为0.150～0.885的FA-PS。扫描电子显微镜和N₂-吸附/脱附结果表明,PS的比表面积为67.74 m²/g,平均孔径为20.23 nm,酯化改性后孔变得小而密集,FA-PS的比表面积可达到83.50 m²/g,平均孔径低至8.59 nm,可归属于介孔材料范畴。傅立叶变换红外光谱和¹³C固体核磁共振光谱证明FA和PS之间形成了酯键。X射线衍射显示PS处于非晶无序状态,而FA-PS发生晶型回生形成了新的结晶结构。FA-PS具备较强的抗氧化活性,酯化后水溶性得到改善,体外抗消化能力显著提升(P<0.05)。结果表明,FA-PS具备有效的纳米级...     

哌啶交联型聚亚芳基阴离子交换膜的制备

通过聚羟烷基化反应和Menshutkin反应合成了一系列哌啶/传统季铵交联的无醚含氟聚联苯哌啶阴离子膜.在交联和氟化共同作用下,QBPBP/TFAP-X及QAPBP/TFAP-30%膜的溶胀率(4.3%和8.3%, 80℃)均较低.微相分离最明显的QBPBP/TFAP-45%(1.52 meq/g)在80℃下电导率为124.0 mS/cm.哌啶交联的QBPBP/TFAP-X系列膜耐碱性更出色,其中QBPBP/TFAP-45%在80℃的2 mol/L NaOH溶液中处理1 000 h后,电导保留率为94.07%,表明哌啶阳离子的耐碱性优于季铵盐.在521.3 mA/cm²的电流密度下,QBPBP/TFAP-45%膜组装的单电池最大功率密度为266.8 mW/cm².     

燃料电池轿车操纵稳定性仿真分析

轿车改装燃料电池动力系统后,整车参数发生了变化,悬架也相应调整.文中在ADAMS/CAR中建立了某燃料电池轿车整车模型,通过驾驶员控制文件的定义对典型行驶工况进行仿真试验,根据国标对该车的操纵稳定性进行了综合评价.结果显示,由于整车参数变化及悬架的调整使得该车的不足转向特性偏弱,最后分析其原因并提出了改进措施.