Antibacterial poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) fibrous membranes containing quaternary ammonium salts

In this study, antimicrobial membranes based on biodegradable material poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) [P(3HB‐4HB)] and quaternary ammonium salts (QASs) by two methods have been performed. Three QASs with varied alkyl chain lengths have been synthesized successfully and characterized by ¹H nuclear magnetic resonance and Fourier transform infrared. The synthesized QASs were blended with P(3HB‐4HB) and electrospun into composite fibrous membranes or casted into conventional membranes. Electrospun fibrous membranes with large surface areas are a superior type of antimicrobial biomaterials, and they exhibit preferable properties than solution casting membranes. Specifically, electrospun fibrous membranes are tougher and can inactivate both Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli O157:H7 in a contact time of 30 min, whereas the solution casting membranes cannot. The length of alkyl chain in the quaternary ammonium groups on the modified P(3HB‐4HB) membranes is able to influence the antimicrobial activity. This type of antimicrobial material may have potential applications in biomaterial field. Copyright © 2016 John Wiley & Sons, Ltd.     

5-（烯丙氧）甲基-8-羟基喹啉铝配合物的合成和性能研究

以8-羟基喹啉为原料,合成了5-（烯丙氧）甲基-8-羟基喹啉配体及其铝配合物,并通过红外光谱对配体和配合物进行了表征,通过荧光光谱研究了配合物的光致发光性能。     

Flocking of Multi-particle Swarm with Group Coupling Structure and Measurement Delay

We investigate the flocking conditions of a group coupling system with time delays, in which the communication between particles includes inter-group and intra-group interactions, and the time delay comes from the theory of moving object observation. As an effective model, we introduce a system of nonlinear functional differential equations to describe its dynamic evolution mechanism. By constructing two differential inequalities on velocity and velocity fluctuation from a continuity argument, and using the Lyapunov functional approach, we present some sufficient conditions for the existence of asymptotic flocking solutions to the coupling system, in which an upper bound of the delay allowed by the system is quantitatively given to ensure the emergence of flocking behavior. All results are novel and can be illustrated by using some specific numerical simulations.     

植物油的1H NMR和13C NMR的测定

油酸和亚油酸,是人体必需的营养成份,具有抗癌,防止动脉硬化,降脂减压等作用,因而它们在治疗一些癌症及减肥降血脂等方面取得了较好的疗效^[1-3]。通常油酸,亚油酸和其他脂肪酸以甘油酯的形式,大量地存在于植物油中。本文用¹H NMR测定了5种植物油各组峰面积积分,按文献[4]扣除法,整理了各组峰的积分值,计算出油脂中每摩尔所含各功能团的个数,不饱和度,酯化度等数据。此外,还记了豆油和茶油的¹³C NMR谱,从这两种谱图相关谱线积分值推算出各功能团与甲基基团的比率与¹H NMR谱所得结果接近。并计算出,上述两种油中所含脂肪酸甘油酯和各种不饱和脂肪酸甘油酯的克分子百分数。对测得CCH₂C基团质子自旋晶格弛豫时间T₁进行分析后,给出一经验公式来予以拟合,计算结果与测定值吻合。这一事实说明,油脂中各种组分克分子百分数的计算是可以信赖的。     

TheARGO project: Scientific targets, first results and future perspectives

Summary The ARGO program consists of a balloon-borne mm and sub-mm telescope, devoted to the observation of diffuse radiation in the wavelenth range between 2 mm and 300 μm, at angular scales between 10′ and 5°. We review here the impact of such observations in different fields ranging from Atmospheric Physics to Cosmology. We also quote the results obtained from ARGO's first flight in 1989, and we describe the improved version of ARGO we are currently developing. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

一种新的NMR法测定溶液中碱土金属混合物的方法原理(英文)

本文研究了碱土金属离子-锶、钡及钙可以形成在NMR标尺上是稳定配合物的条件。找到了最适合得到这样的配合物的配体-C222穴醚。研究并归属了碱土金属离子以及碱金属-钠、钾及锂配合物在氯仿中的~(13)C NMR谱。检测出了可用于分析自由配体及其与碱土金属配合物的~(13)C NMR信号,还研究了不同比例混合物的碱土金属及碱金属在氯仿中的~(13)C NMR谱,得到了当自由配体过量时在钡、钙及锶每种金属浓度为1×10~(-3)M的谱中可观测到相当于自由配体及每种离子配合的配体的分立信号。这些信号的积分值的精度可以定量地表征金属离子的浓度,所得结果为首次观测到的。它可以作为用~(13)C NMR波谱建立新的无机分析方法。文中并阐明了作溶液中碱土金属混合物NMR测定方法的具体条件,并讨论了将这一方法扩展到包括一系列碱金属在内的更复杂的混合物的可能性。试验在VARIAN XL-200波谱仪上进行。     

Pumped shot noise in adiabatically modulated graphene-based double-barrier structures

Quantum pumping processes are accompanied by considerable quantum noise. Based on the scattering approach, we investigated the pumped shot noise properties in adiabatically modulated graphene-based double-barrier structures. It is found that compared with the Poisson processes, the pumped shot noise is dramatically enhanced where the dc pumped current changes flow direction, which demonstrates the effect of the Klein paradox.     

改性壳聚糖抗菌纳米微球的制备

以卤胺化合物为抗菌基团对壳聚糖接枝改性, 并制备成纳米微球, 提高壳聚糖的抗菌性能. 通过核磁共振和紫外光谱对改性壳聚糖进行结构表征; 探讨了改性壳聚糖浓度、 三聚磷酸钠浓度及两者体积比对纳米微球的形成和粒径分布的影响; 测定了纳米微球的抗菌性能. 结果表明, 在改性壳聚糖浓度为4.0 mg/mL, 三聚磷酸钠浓度为2.0 mg/mL时, 形成的纳米微球形态稳定, 粒径分布均匀, 氯化后的纳米微球可在30 min内杀灭10⁷ cfu(cfu为单位体积中的菌落总数)的金黄色葡萄球菌和大肠杆菌, 表现出优异的抗菌性能.     

假肢接受腔-人体皮肤界面往复摩擦能量损耗的研究

利用万能材料试验机和多功能数据采集分析系统,在往复摩擦模式下模拟假肢接收腔-残肢皮肤穿戴界面,研究了不同切向力作用下两种常用的假肢接受腔材料与皮肤的摩擦能量损耗.结果表明:接受腔-皮肤界面往复摩擦过程中,随着切向力的增加,皮肤发生的弹性变形增大,皮肤摩擦前后的温差增加,摩擦过程中的能量损耗增大.接受腔材料表面结构直接影响着残疾人穿戴假肢的舒适性.相较于表面粗糙度较大的国内生产接受腔材料,表面粗糙度较小的进口接受腔材料降低了皮肤的摩擦能耗,减轻了皮肤的发热和变形,降低了皮肤损伤的风险,提高了与皮肤界面的适配性.     

CVL横向泵浦的染料激光放大器中泵浦光纵向分布对效率的影响

本文建立了一套较为全面地描述铜蒸汽激光器横向泵浦的染料激光放大器中各种效应的速率方程．首次计算、分析了泵渝光纵向分布在不同输入信号下对转换效率的影响，并且讨论了所得结果对于设计和改进染料激光放大器的理论指导意义．