小型平板铀裂变电离室研制

为了测量特定实验条件下狭小空间内中子注量率分布,研制了小型平板浓缩铀裂变电离室,该裂变室具有体积小、结构材料少等优点。论文叙述了裂变电离室的结构和制作工艺,通过测量自发衰变α粒子谱、裂变碎片谱对裂变电离室的性能进行了测试和评定,并标定了裂变电离室测量裂变碎片的探测效率。从指标上看,裂变电离室能达到设计要求和目的,可用于中子注量率的测量。     

水泥材料的老化及其对Pu的迁移阻滞性能的影响

采用干湿交替加热的方式对水泥进行了加速老化,以模拟高放废物水泥固化材料的缓慢自然老化过程。通过动态柱实验的方法,研究了水泥的老化过程对239 Pu迁移过程的影响。结果表明,随着老化时间的加长,水泥材料的比表面积和孔隙率减小,碱性减弱,吸附阻滞Pu迁移的能力降低。然而,老化的水泥材料仍然具有很强的阻滞Pu迁移的能力,如老化15d后,Pu通过水泥柱的回收率仍小于2.5%。     

Design of the Transmission Lines for 140 GHz ECRH System on HL-2A

A new 140 GHz/2 MW/3 s electron cyclotron resonance heating （ECRH） system composed of two units is now being constructed on HL-2A. As a part of the system, two trans- mission lines marked No.7 ＆ 8 play the role of carrying microwave power from two gyrotrons to the tokamak port. Based on the oversized circular corrugated waveguide technology, an evacu~ ated transmission system with high power capability and high transmission efficiency is designed. Details are presented for the design of the corrugated waveguide, the layout of the proposed lines and the vacuum pumping system. Then mode conversion losses due to coupling, misalignment, bends and gaps are discussed to serve as a reference for analyzing the transmission efficiency and alignment. Finally, a dual-modes propagation case consisting of the HEll and LPn even modes is discussed.     

电沉积制备纳米晶铁-镍-铬合金箔工艺及机理研究

以复合羧酸为配位剂,在含三价铬离子的水溶液中,电沉积制备Fe-Ni-Cr合金箔,研究铬盐浓度、电流密度和供电方式等对箔成分和成箔性能的影响,采用SEM、TEM、XRD和EDS对合金箔进行表征,对合金箔的力学、电和耐蚀性能进行研究,并研究合金箔沉积机理。结果表明,采用复合羧酸体系脉冲电沉积可制备出Cr的质量分数为5%~8%的高Cr光滑合金箔,其微观形貌为紧密堆砌的球状颗粒,晶粒尺寸10nm以内,主相为Cr与α-Fe或γ-Fe形成的固溶体。合金箔中Cr含量提高,箔的电阻率、硬度和耐蚀性也随之升高。Fe-Ni-Cr合金共沉积为电化学控制,由于Cr3+加入,合金沉积阻力加大,速度降低。     

Inhibition of biofilm formation of Pseudomonas aeruginosa by an acylated homoserine lactones-containing culture extract

The objective of this study was to examine the effect of an acylated homoserine lactones-containing culture extract (AHL-CCE) on bacterial growth, enzyme activity and biofilm formation of Pseudomonas aeruginosa. Chicken breast muscle broth in which P. aeruginosa had been grown for 24 h at 20 °C was extracted with acidified ethyl acetate, the solvent was evaporated and the residue was dissolved in water and heated at 100 °C for 15 min. Thin-layer chromatography combined with Agrobacterium tumefaciens KYC55-based bioassays indicated the presence of C₄-, C₆-, C₈- and C₁₂-homoserine lactones in the extract. The addition of AHL-CCE to a culture of P. aeruginosa caused the bacteria to reach their highest count after 36 h whereas cultures without the extract required 72 h to reach their peak counts, but the maximum cell count was higher for the extract-free culture. No biofilm was detected when P. aeruginosa was cultured in chicken broth at 10 °C when the extract was present. Addition of extract reduced proteolysis of actin, troponin-T and tropomyosin by P. aeruginosa, but had no effect on lipase activity. Therefore, AHL-CCE can be used to reduce the bacterial growth time and inhibit biofilm formation; thus, benefiting food safety and quality.     

紫胶色素对锦纶纤维的染色热力学研究

为了探讨紫胶色素在锦纶纤维上的染色行为,为染色工艺的优化提供理论参考,进行紫胶上染锦纶纤维的染色平衡实验。用Freundlich、Langmuir和Redlich-Peterson型3种理论吸附模型对80、90℃下的实验数据进行拟合,并计算出染色亲和力、染色热和染色熵等热力学参数。结果表明,紫胶色素在锦纶上的吸附最符合RedlichPeterson型吸附模型,亲和力和吸附量都随着温度的升高而减小,染色热和染色熵分别为-55.45 kJ/mol和-111.96 J/(mol·K),说明染色过程是放热和自发的过程。     

冷榨亚麻籽油的流变特性研究

通过低温压榨亚麻籽获得冷榨亚麻籽油（cold—pressed flaxseed oil,CFO）,并分析其主要理化指标,着重研究CFO的静态、动态流变特性,同时分别采用Casson、Herschel-Bulkley和Bingham模型对其流体行为进行拟合,并采用Arrhenius方程分析其粘度热动力学参数。研究结果表明：在剪切速率为0．1～200s“下,CFO由非牛顿流体逐渐转化为牛顿流体;当剪切速率大于10s^-1时,CFO呈牛顿流体;同时分析得出CFO的粘度活化能为3095．4cal／mol;CFO的粘度、剪切应力、损耗模量、塑性稠度系数、高剪切极限粘度和稠度系数随着温度升高而降低,但是温度变化对CFO的贮能模量影响不显著;另外通过比较3个流变模型得出Bingham模型适用于CFO。     

江香薷不同极性提取物的抗菌活性研究

采用溶剂萃取法制备5种江香薷提取物,并用纸片法和肉汤稀释法比较了这5种提取物分别对金黄色葡萄球菌、大肠杆菌和枯草芽孢杆菌等常见菌的体外抗菌效果,结果显示江香薷的乙酸乙酯提取物对三种检测细菌的MIC为15.60μg/mL,石油醚提取物、正丁醇提取物和醇溶物的MIC为31.25μg/mL,而水提物在实验浓度范围内抗菌作用不明显。由此可知江香薷具有抗菌活性,其中以乙酸乙酯提取物作用最显著。     

多轴三维织机斜纱引入机构的设计

为了避免三维机织物各向异性突出的缺陷,通过引入斜纱来增强三维机织物的平面属性,以适应航空航天等应用领域对三维机织物各向同性的性能要求。介绍了多轴三维织物的组织结构,设计其织造用的斜纱引导机构,该机构由4个特殊直线步进电机组成;在UG中对该机构进行建模并在Ansoft Maxwell中建立单个直线电机二维模型,并对此电机进行静态磁场分析以及推力仿真。为多轴三维织机虚拟样机的建模、设计与仿真及其物理样机的研制奠定必要的基础。     

金樱子黄酮两种提取工艺优化及比较

以金樱子果实为研究对象,用黄酮得率作为衡量提取工艺的指标。通过单因素实验、正交实验优化传统加热提法和微波助提法提取金樱子果实中黄酮的提取工艺,并比较其工艺条件。验证实验表明,传统加热提法最佳工艺测得金樱子果实黄酮得率为7.84%,相对标准偏差(RSD)为0.89%;微波助提法最佳工艺测得金樱子果实黄酮得率为9.06%,相对标准偏差(RSD)为1.01%。运用微波技术提取金樱子果实中黄酮含量减少了提取时间,提高了效率。因此,恰当的提取条件可使金樱子果实中黄酮的得率更高。