Bio-nanocomposites by assembling of gelatin and layered perovskite mixed oxides

A new class of bio-nanocomposites based on hybrid gelatin-perovskite hydrogels was prepared by mixing exfoliated perovskite-tetraalkylammonium species in aqueous suspensions with gelatin solutions. Colloidal nanosheets derived from the CsCa2Nb3O10 layered perovskite re-stacked in the gelatin solutions give bio-nanocomposite materials with different content in the inorganic moiety. These films can be easily processed as homogeneous self-supported films. The partial exfoliation of the pristine mixed oxide is produced from alkylammonium exchanged phases, being the tetraalkylammonium ions (tetraethylammonium, TEA+) an efficient intermediate to give the colloid phase constituted by well exfoliated materials useful to generate homogeneous films. The nanosheets are highly oriented in the bio-nanocomposite films in agreement with the XRD patterns and the FTIR dichroism. This orientation could be considered as a characteristic of this type of hybrid materials leading to new potential applications. In this way, we have observed that the assembling of perovskite to gelatin produces a greater increase of the dielectric permittivity than the dielectric loss in the studied samples.     

Achieving stabilization in interferometric logic operations

Interferometric systems with amplitude beam splitters can implement reversible operations that, on detection, become Boolean operators. Being passive, they consume no energy, do not limit the operating bandwidth, and have negligible latency. Unfortunately, conventional interferometric systems are notoriously sensitive to uncontrolled disturbances. Here the use of polarization in a common-path interferometric logic gate with and without polarization beam splitters is explored as an attractive alternative to overcome those difficulties. Two of three device configurations considered offer significant stability and lower drive modulator voltage as advantages over the previous systems. The first experimental tests of such a system are reported. Common-path interferometry lends itself to even more stability and robustness by compatibility with no-air-gap, solid optics.     

Electrochemical and XAFS studies of effects of carbonate on the oxidation of arsenite

Measurements of electrochemical (EC) arsenite oxidation demonstrated thatthe arsenite oxidation current increased in the presence of carbonate while the potential of the onset of EC arsenite oxidation exhibited a strong shift toward less positive values. Examination of pH and total carbonate concentration effects on the EC arsenite oxidation parameters showed that they were affected solely by the concentration of carbonate ion CO3(2-), which appeared to form relatively weak mono- and dicarbonate complexes with arsenite. The EC activity of these complexes was determined to be almost an order of magnitude higher than that of free arsenite. However, X-ray absorption fine-structure (XAFS) measurements did not show any changes in the properties of the As(III) inner complexation shell associated with the presence of the bound carbonate ions. It was accordingly concluded that the strength of bonds between the bound carbonate and As(III) is close to that for As(III)-OH- interactions. The acceleration of the oxidation of carbonate-As(III) complexes was hypothesized to be associated with an additional pathway of the formation of As(IV) intermediates, in which the carbonate group present in the As(III) inner shell provides an electron to form a bound carbonate radical and also a good leaving group for facile cleavage from the transient As(IV) species.     

综合录井地质分析平台

针对目前上交综合录井资料利用率不高的现状,该文提出了开发“综合录井地质分析平台”意见,并系统介绍了研制目的、开发环境和技术关键等内容。以期实现功能强、界面友好、操作灵活,真正成为录井地质师的有效工具。结合录井资料信息量大、随钻实时性和第一性的特点,采用多用户管理等方式,面向用户开放,有利于扩大、提高录井资料的综合利用水平,实现录井资料的广泛应用和信息共享。     

枣园油田油藏精细描述技术与方法

在查明油田构造、沉积体系、储集体几何形态和储层参数的空间分布规律,确定油藏类型及油气储量,阐明油气控制因素及油气富集、高产区分布规律的基础上,为编制、调整开发方案,提供了完整的符合地下情况的全套数据和地质依据,还提出适合枣园油田特殊非均质油藏的描述及综合评价技术,并综合构造、沉积、储层成岩后生作用的研究,对储层渗流屏障、渗流差异、敏感性及孔隙渗流等方面的研究,提出并形成了油藏渗流地质学新观点,为枣园油田和同类油藏的勘探开发,提供了理论基础.     

Activated carbons from sewage sludge and discarded tyres: production and optimization

This is a study about making use of two residual materials such as sludges from a sewage treatment plant and discarded tyres to generate activated carbons and later optimize the production process. H2SO4 and ZnCl2 were used as chemical activating agents. Liquid-phase adsorption tests were made using the produced carbons to retain methylene blue and iodine. The best precursor was sludge activated with ZnCl2. After optimization studies, the best production methodology involved a 1:1 ratio of sludge and ZnCl2, a heating rate of 5 degrees C/min up to 650 degrees C and a residence time of 5 min. The resulting materials adsorbed up to 139.4 mg/g of methylene blue and 1358.5 mg/g of iodine. Nevertheless these carbons may leach Zn while using. To avoid this two treatments were carried out: one consisting of a coating with a polymer and another involving an intensive washing, which was seen to be more efficient.     

地方科技社团可持续发展的对策研究——基于深圳的经验分析

科技社团是科技人员基于学术自由、平等交流、互动自主机制而自愿结合形成的社会组织,在区域创新体系建设、创新文化营造以及科技事业发展中发挥着重要作用。基于深圳科技社团的发展经验,从优化社团成长环境、做好人才战略、推进精品工程、畅通传播渠道、构筑对外交流平台等方面提出了地方科技社团可持续发展的对策。