预处理浸泡对聚酰亚胺重离子微孔膜蚀刻的影响

聚酰亚胺(Polyimide,PI)膜是一种新型的有机膜,具有耐高温、耐强酸和耐辐射等特性,用其制备的重离子微孔膜可以用于电池隔膜和放射性废气过滤等特殊领域。应用中国原子能科学研究院HI-13串列加速器产生的重离子束32S离子轰击25?m的PI薄膜,再对薄膜进行化学蚀刻处理,使由重离子辐照损伤产生的径迹形成微孔。为改善微孔质量,在化学蚀刻前采用具有强氧化性溶液对PI膜进行预处理浸泡,系统分析了常温下采用高锰酸钾和双氧水两种溶液浸泡不同时间对PI膜化学蚀刻的影响。实验结果显示,预处理浸泡可明显加快PI膜的径迹蚀刻速率,缩短蚀刻时间,减小微孔的锥角和提高PI重离子微孔膜的蚀刻质量。     

PⅢD技术制备Ti/DLC纳米多层薄膜

采用等离子体浸没离子注入与沉积(PⅢ&D)技术在2Cr13钢表面制备了Ti/DLC纳米多层薄膜.分析了膜层的微观结构和机械特性.实验结果表明:纳米多层膜具有完整、清晰的调制层结构,薄膜的显微硬度均得到明显的提高.硬度较低的膜层具有较好的膜基结合强度和优良的摩擦性能,从综合性能看:纳米多层薄膜保持了类金刚石(DLC)薄膜低摩擦系数的特性,具有良好的承载能力以及膜一基结合特性.     

CaCO3/SiO2纳米粒子的表面改性及其对天然胶乳膜抗紫外光老化性能的影响

以十二烷基三甲氧基硅烷(DTMS)为改性剂,分别对CaCO_3和SiO_2纳米粒子进行表面改性,将改性后无机纳米颗粒按不同质量比混合填充天然橡胶胶乳(NRL)制备CaCO_3/SiO_2/NRL硫化胶乳膜,研究了改性纳米CaCO_3与纳米SiO_2混合体系对天然胶乳膜(NRLF)抗紫外光老化性能的影响。通过傅里叶变换红外光谱、X射线衍射、热重分析、接触角测定等手段表征改性前后无机纳米颗粒的结构及性能的变化;通过力学性能测试和扫描电子显微镜探究CaCO_3和SiO_2纳米体系不同质量比的硫化胶乳膜抗紫外光老化性能。结果表明:长链DTMS与无机纳米颗粒间能形成有机化学键合,有效阻止了纳米颗粒间团聚,提高了两种纳米粒子在胶体中的分散性;改性后无机纳米颗粒在NRLF体系中能形成网状结构,复合材料的力学性能明显提高;当改性后纳米CaCO_3和纳米SiO_2质量比为4∶6时,复合材料具有良好的抗紫外光老化能力。     

辐射接枝制备有机-无机纳米杂化粒子及其分散性能

本文采用共辐射接枝技术,在室温真空氛围中利用γ射线引发一步制备聚偏氟乙烯(PVDF)接枝改性的钛酸钡(BT)有机-无机纳米杂化粒子.通过傅里叶变换红外光谱(FTIR)、热失重分析仪(TGA)以及透射电子显微镜(TEM)对产物进行分析,证明了PVDF成功接枝在钛酸钡纳米粒子表面.利用差示扫描量热仪(DSC)与X射线衍射仪...     

11-巯基十一烷酸包裹的金纳米颗粒薄膜的二次电子发射

采用改进的Peterk合成法合成11-巯基十一烷酸(Mercaptoundecanoic Acid,MUA)包覆的金纳米颗粒。通过调控MUA与氯金酸质量比,得到分布均匀且稳定性较好的不同粒径(3 nm)的纳米金颗粒前驱体溶液,进而滴加该溶液形成薄膜。扫描电子显微镜(Scanning Electron Microscope,SEM)观测到薄膜中具有大量微米级的块状集团。同步辐射掠入射X射线衍射(Grazing Incidence X-ray Diffraction,GIXRD)揭示其具有面外长程有序的超晶格结构;X射线光电子谱(X-ray Photoelectron Spectroscopy,XPS)证实薄膜中Au-S键的形成。通过紫外光电子能谱(Ultraviolet Photoelectron Spectroscopy,UPS)进一步发现常温下1.5 nm粒径的薄膜具有比单晶金样品强10倍的优异二次电子发射能力,且发射峰半高宽是单晶金样品的1/4。本研究表明,MUA包覆的金纳米薄膜在电子发射源以及光电探测上具有应用前景。     

X射线辐照合成金纳米颗粒及其原位表征

X射线辐照合成无机纳米粒子具有简单、清洁、高效等优点,是一种绿色合成方法.X射线技术,如X射线光电子能谱(XPS)、X射线吸收精细结构谱(XAFS)等,特别是同步辐射X射线技术的应用和发展,为人们探索纳米材料的结构信息提供了强大的工具.然而,利用X射线辐照合成金纳米颗粒及利用X射线技术原位探索金纳米颗粒的生长机理的综述...     

热处理增强Au纳米颗粒超薄膜光电子发射的研究

本文制备了平均直径为1.4 nm的11-巯基十一烷酸(Mercaptoundecanoic acid,MUA)修饰的金纳米颗粒,随后通过硅晶片上壳聚糖薄涂层静电吸附制备了厚度约为10 nm的超薄膜,原子力显微镜(Atomic Force Microscopy,AFM)和扫描电子显微镜(Scanning Electron Microscopy,SEM)表明金纳米颗粒在薄膜中分布较为均匀且薄膜较平整。进一步采用紫外光电子能谱(Ultraviolet Photoelectron Spectroscopy,UPS)研究了不同热处理温度对超薄膜的二次电子发射能力的影响。结果表明,适度的热处理有助于超薄膜二次电子发射强度的提高,尤其是经150°C热处理的薄膜二次电子发射峰强是未处理样品的4倍,更高的热处理温度造成二次电子发射峰强度急剧下降。本文结果有助于推动有机配体金纳米颗粒超薄膜在光电子发射材料方面的应用。     

宽禁带半导体低维纳米结构力敏效应的研究

选择了均匀沉淀法来制备氧化锌纳米颗粒,用PEG200进行表面改性,使制备的氧化锌纳米颗粒更加分散。利用X-射线衍射(XRD)、扫描电子显微镜(SEM)表征证明了制备样品是粒径约20nm的氧化锌纳米颗粒,结晶性良好、粒径均匀,单个颗粒呈米粒状,颗粒相连呈薄片状。最后通过半导体特性分析仪(Agilent 4156C)和精密阻抗特性分析仪(Agilent 4284A)分别测量了受不同力时的氧化锌纳米颗粒的特性粘度(I-V特性)和阻抗值,并进行分析,得出其力敏特性。分析得出氧化锌纳米颗粒应用于加速度传感器、压力传感器、位移传感器、振动传感器、角度传感器等的可能性,具有广泛的应用前景。     

电子束蚀刻聚酰亚胺制备微孔分离膜的研究

以电子束蚀刻技术,结合微孔掩膜和溶液氧化腐蚀的方法,制备聚酰亚胺(Polyimide,PI)微孔分离膜.通过称重法,讨论了吸收剂量、腐蚀时间和腐蚀温度等因素对PI基膜蚀刻和腐蚀的影响,结果表明,随着吸收剂量、腐蚀温度和腐蚀时间的增加,PI基膜更容易被腐蚀;IR检测结果表明,辐照导致PI分子化学键断裂,分子量变小,是辐照PI腐蚀失重率增加的原因;试验对微孔铅和铁掩膜遮蔽的PI基膜进行电子辐照,再用浓硫酸和重铬酸钾混合溶液腐蚀辐照PI基膜,得到具有规则且垂直孔道的聚酰亚胺微孔分离膜.     

惯性约束聚变用聚酰亚胺靶丸的研究进展

综述了近年来国内外在惯性约束聚变实验用聚酰亚胺(PI)靶丸方面的研究与应用进展情况.从ICF实验用靶的性能要求、常用PI的化学结构、PI靶丸的装配方法以及目前PI靶丸应用过程中存在的问题等几个方面进行了论述.在此基础上提出了PI靶丸的研究方向.     

A cascade control strategy for a space nuclear reactor system

This work presents a linear feedback control for the space nuclear reactor power system TOPAZ II. The point-kinetics approximation with six-delayed-neutron-group is used to represent the neutron field dynamics. A favorable choice of input control variables is demostrated, which leads to a cascade control configuration with two classical either PI or P controllers. The strategy is based on linearizing-like feedback control endowed with a modeling error estimator via a reduced order-observer. The effectiveness of the control law to the tracking of a given thermal power profile in the start-up regime and the tracking of a given electric power profile in the operation regime are illustrated via numerical simulations.     

鸟亲和素的结构改造和核素标记

采用ＮａＩＯ４氧经鸟亲和素的寡糖链产生醛基后，与章胺偶联，紫我证明每个Ａｖ联了５－６个章胺基团。用丁二酸酐同Ａｖ上的赖氨酸残基酰基化反应，得到ｓｕｃ－Ａｖ等电点显著低于Ａｖ的等电点。＾１２５Ｉ标记的各种Ａｖ衍生物和生物素的结合能力明显不同。     

基于智能预测的反应堆功率调节研究

针对比例-积分（PI）控制需进一步提高控制性能的需求,采用单步预测控制方案结合在线T-S模糊辨识和粒子群优化算法设计反应堆功率控制器。该控制器在不同工况下的仿真结果表明,预测控制在调节响应速度、超调量等指标上效果优于原先采用的PI控制。      

Threshold of parametric instability in the ionospheric heating experiments

Many observations in the ionospheric heating experiment, by a powerful high frequency electromagnetic wave with ordinary polarization launched from a ground-based facility, is attributed to parametric instability (PI). In this paper, the general dispersion relation and the threshold of the PI excitation in the heating experiment are derived by considering the inhomogeneous spatial distribution of pump wave field. It is shown that the threshold of PI is influenced by the effective electron and ion collision frequencies and the pump wave frequency. Both collision and Landau damping should be considered in the PI calculation. The derived threshold expression has been used to calculate the required threshold for excitation of PI for several ionospheric conditions during heating experiments conducted employing EISCAT high frequency transmitter in Troms?, Norway, on 2nd October 1998, 8th November 2001, 19th October 2012 and 7th July 2014. The results indicate that the calculated threshold is in good agreement with the experimental observations.     

基于Hilbert-Huang变换和BP神经网络的核级电动阀门退化趋势预测

核级电动阀门服役环境恶劣,极易发生退化失效。为准确预测核级电动阀门性能退化趋势,采用Hilbert-Huang变换（HHT）和反向传播神经网络（BPNN）相结合的方法（HHT-BPNN）对核级电动阀门的退化状态进行预测。本文采用某次核级电动阀门可靠性试验的振动信号对电动阀门退化趋势进行预测,结果显示该方法能准确预测出核级电动阀门的3种退化状态,且其相对误差在可接受范围内。研究表明HHT能够有效提取信号的退化信息,BPNN能够准确预测核级电动阀门的退化趋势,HHT-BPNN预测方法能有效解决核级电动阀门性能退化预测困难的问题。      

A new physical protection measure for evaluating risks at nuclear facilities

The Physical Protection (PP) measures for evaluating risks at nuclear facilities have been developed. The developed measures can be used to not only evaluate the physical protection status of operational nuclear facilities, but also for the next generation of nuclear systems such as the SFR (Sodium Fast Reactor) and the VHTR (Very High Temperature Reactor). These measures can substitute those existing methodologies developed by the Gen-IV PR&PP group and the INPRO. These measures have been adapted to hypothetical nuclear facilities, and scenarios have been created to analyze PP risk quantitatively. The PP measures developed in this study contain Probability of Interruption (PI), Probability of Neutralization (PN), Consequences (C), Fissile Material Type (MT) and Effectiveness of Physical Protection Resources (EPR). In this paper, tools and tables for calculating each PP measure are suggested and illustrated in detail. The PI and PN measures can be calculated quantitatively using these tools. A new computer code for calculating PI has also been developed. The EPR, MT and C measures were obtained from tables developed by collecting and analyzing related information. Computational results of the PP measures in five different scenarios, and at three different facilities demonstrate the effectiveness of the methodology developed. The results obtained are represented in a spider diagram (after normalizing the measure calculated). The value of PI and C changed because of the scenario; but the other three measures, EPR, MT and PN (determined by the characteristics of the facility) did not vary. It is expected that by using a larger number of refined scenarios more reliable information will be provided. It is also anticipated that the PP measures developed in this study can be applied to operational nuclear facilities, as well as a future nuclear systems under development.     

Photoradiation processes in combined polymeric materials

The methods of ESR, optical and mass-spectroscopy have been used to study the formation and decay of active intermediates, radiation and photoradiation gas evolution in a series of combined polymeric materials. The investigated samples were films of polyimide (PI), one- or two-side coated PI–fluoroplast, poly(ethylene terephthalate) (PET), PET coated with polyacryl on both sides, etc.Different coatings and polymeric substrates have been established to produce a mutual effect on the radiation- and photo-induced transformations of the combined polymers at the stage of radical formation and gas evolution. Thus, γ-irradiation of PI–fluoroplast films at 300 K intensifies the radiation-chemical processes in the fluorinated coatings, namely, the radiation-chemical yield of macroradicals in the coatings is several times higher than that in fluoro-containing polymers. In the PET film coated with polyacryl the yield of macroradicals related to polyacrylic acid is significantly lower than the value generally cited in the publications. A mutual effect of the coatings and substrates on the radiation and photoradiation-induced gas evolution is even more noticeable. Thus, a gas mixture of the PI–fluoroplast film contains lower amounts of carbon oxide and fluorinated products and no hydrogen at all. The interphase processes, distortion of the boundary layer structure, electronic equilibrium, mutual effect of the evolved gases, etc. can account for the reasons of such non-additivity.     

Application of fuzzy logic control system for regulation of differential pressure in Liquid Zone Control System

In this paper, fuzzy control scheme has been proposed for generating regulating signals to feed and bleed control valves, which are used in Liquid Zone Control System (LZCS) for maintaining constant pressure difference between gas outlet header and delay tank. The LZCS and the existing PI controller are briefly described. It is followed by the design of Fuzzy Controller. It consists of seven symmetric triangular input membership functions and output membership functions each. Mamdani implication has been used to infer output contribution from each rule. The centroid type of defuzzification method is employed to get the crisp output values. The fuzzy logic controller for feed and bleed control valves so designed has been validated by performing a variety of experiments on a full scale LZCS test setup at Bhabha Atomic Research Centre and its performance is analyzed and compared to that obtained with existing PI controller. In comparison with the existing PI controller, the fuzzy logic controller’s performance is superior in all cases considered.