天津市冬季蜂窝状溶蚀器涂层溶液最适浓度研究

在特定时间特定地点利用溶蚀器PM2.5采样系统进行PM2.5采样前,应首先确定溶蚀器涂层溶液最适浓度.为确定在天津市冬季利用蜂窝状溶蚀器PM2.5采样系统采样的最优化条件,于2014年1月1日∽2月24日,在南开大学理化楼楼顶进行蜂窝状溶蚀器涂层溶液最适浓度的条件实验.结果表明：在天津地区冬季,蜂窝状溶蚀器的碳酸钠涂层溶液最适浓度为4%,柠檬酸涂层溶液最适浓度为5%;环境空气中HCl气体对PM2.5中Cl-的质量浓度测定影响不大,而HNO3、SO2、NH3等酸/碱性气体对PM2.5中相对应离子的质量浓度测定影响较大.

天津市夏季蜂窝状溶蚀器涂层溶液浓度确定的实验研究

于2013年7月1日～8月31日,在天津市南开大学理化楼楼顶,采用蜂窝状溶蚀器进行了溶蚀器涂层溶液最适浓度的探究实验.结果表明,在天津夏季,蜂窝状溶蚀器的碳酸钠涂层溶液最适浓度为3%,柠檬酸涂层溶液最适浓度为6%.含有溶蚀器系统的颗粒物采样法与传统采样法对比发现,含蜂窝状溶蚀器的采样系统所得到的PM2.5样品浓度有86%低于传统方法所得到的PM2.5样品浓度,其原因主要为1酸/碱性气体被去除,使其无法与富集在采样膜上的颗粒物发生反应,也无法吸附到颗粒物上;2溶蚀器系统采样过程中,部分颗粒物被捕集到溶蚀器上;3酸/碱性气体被去除,导致气-粒平衡被打破,部分颗粒物组分向气态转化.

涂层尿素——一种新型高效、长效氮肥

到2000年,我国粮食生产必须在现在的基础上再增1000亿斤,否则将难以适应国民经济的发展和人口增长的需要。怎么样才能实现这一目标呢?这需要从多方面进行努力。改良化肥就是其中的一个重要方面。 尿素是我国化肥的一个主要品种。但是,我国施用的尿素,其氮素利用率只有35％-40％

化肥新秀——涂层尿素

氮素化肥施用于田地后,只有30％—40％被作物吸收。为了解决这一难题,广州氮肥厂研制成功一种溶液,以胶态物质为载体,加入一定比例的硼、锌、铁、锰、钼等微量元素,制成涂层溶液,喷于普通尿素颗粒表面。这就是高效涂层复合氮肥,也称涂层尿素。经各省多年的试验、示范、推广证明。涂层尿素较之普通尿素有以下优点:

涂层尿素的施用及加工

一、特点和肥效 高效涂层尿素是一种被涂层物质包裹的尿素,与一般尿素相比,具有防潮、防结块的良好性能,在土壤中的淋失和氨挥发少,氮素分解平缓,供应长期而稳定,作物对氮素的吸收利用率比一般尿素高6％～8％,它具有缓效、长效和氮利用率高的特点。

环形溶蚀器大气颗粒物采集系统条件实验研究

为确定环形溶蚀器大气颗粒物采集系统的最优化条件,于2008年夏季与冬季在北京市进行了关于优化环形溶蚀器涂渍溶液浓度的条件实验。结果表明:为保障大气中酸碱性气体的去除效率达到95%以上,环形溶蚀器中柠檬酸涂渍溶液的优化浓度在夏季和冬季分别为6%与3%;环形溶蚀器中碳酸钠涂渍溶液的优化浓度在夏季和冬季分别为2%与4%。讨论说明在特定地点特定时间利用环形溶蚀器大气颗粒物采集系统采样前,确定环形溶蚀器涂层溶液优化浓度的必要性。

环形扩散管法测定北京市大气中HNO_3和HNO_2的条件优化与应用研究

为研究北京市大气中HNO_3和HNO_2的污染特征,进行了环形扩散管法涂层溶液最佳浓度确定条件优化试验,并于2014年秋季在北京市开展了应用研究。结果表明:环形扩散管中Na_2CO_3涂层溶液的浓度为2%时,大气中酸性气体的去除率达到90%以上;利用优化的环形扩散管方法对北京市城区大气中的HNO_3和HNO_2浓度进行了测定,观测期间大气中HNO_3和HNO_2的浓度分别为0.77~3.23和1.12~5.51μg/m^3,平均值分别为2.33和2.96μg/m^3。研究区大气中HNO_2浓度高于HNO_3,一方面可能由于采样期间光照较弱,HNO_2光解能力降低,另一方面可能由于采样点位于交通干道附近,来自汽车尾气排放的NOx发生均相和非均相反应。大气中HNO_3浓度在雾霾天时最高,其次为晴天;HNO_2浓度也是雾霾天最高,且远高于晴天。

Corrosion behavior of Hastelloy C22 coating produced by laser cladding in static and cavitation acid solution

The Hastelloy C22 coatings on Q235 steel substrate were produced by high power diode laser cladding technique. Their corrosion behaviors in static and cavitation hydrochloric, sulfuric and nitric acid solutions were investigated. The electrochemical results show that corrosion resistance of coatings in static acid solutions is higher than that in cavitation ones. In each case, coating corrosion resistance in descending order is in nitric, sulfuric and hydrochloric acid solutions. Obvious erosion-corrosion morphology and serious intercrystalline corrosion of coating are noticed in cavitation hydrochloric acid solution. This is mainly ascribed to the aggressive ions in hydrochloric acid solution and mechanical effect from cavitation bubbles collapse. While coating after corrosion test in cavitation nitric acid solution shows nearly unchanged surface morphology. The results indicate that the associated action of cavitation and property of acid solution determines the corrosion development of coating. Hastelloy C22 coating exhibits better corrosion resistance in oxidizing acid solution for the stable formation of dense oxide film on the surface.

对于一种用于收集大气及其粒子的玻璃制蜂窝状溶蚀器/过滤器采集系统的研制和评价

目前所使用的环形溶蚀器/过滤器采集技术对大气研究有着极其重要的作用。但是这种仪器的造价较高、操作相对复杂。为此我们研制出了一种可替代系统。该系统在保持并改进了原系统操作特性的同时,在结构上更加紧凑。我们所提出的系统的新颖之处就在于它采用了一个新的溶蚀器元件。此元件拥有众多的六边形小玻璃管,这些小玻璃管被密封在一个大玻璃管之中。新的系统具有下列优点:

The Study of the Varying Characteristics of Cathodic Regions for Defective Coating in 3.5% Sodium Chloride Solution by EIS and WBE

The current distributions over carbon steel under iron red alkyd primer exposed to 3.5% sodium chloride solution were mapped using the wire beam electrode （WBE）. The electrochemical impedance spectroscopy （EIS） of the WBE was carded out to analyze the performance of coating delamination and corrosion behavior of carbon steel beneath defective coating. The EIS data revealed that protective capability of coating decreased with immersion time and the degree of cathodic delamination showed a rapid rise. The current density distribution of WBE indicated that cathodic sites was located at the defect at the beginning of immersion and gradually spread into the intact coating. The cathodic regions were distinguished from the anodic area and distributed over the WBE. The changes of cathodic sites could reflect the deterioration process of defective coating. The cathodic area ratio was a more useful parameter than the cathodic delamination degree to evaluate the coating cathodic delamination. The polarity reversals of electrodes at the defect and beneath coating were observed. A simple discussion of relationship between the blister and the polarity reversal was made from a standpoint of electrochemical distribution. WBE method was able to map and record the changes of local cathodic sites beneath defective coating in real time, which could provide more detailed information about the local degradation of coating.

Electrodeposition behavior and characteristics of Ni-carbon nanotube composite coatings

Ni-CNT (carbon nanotube) composite coatings were processed by electrodeposition and their hardness and corrosion characteristics were investigated with variations of CNT concentration in an electrolyte solution and electrodeposition current density. With increasing the CNT concentration in the electrodeposition bath and the current density, more CNTs are incorporated into Ni matrix. Hardness values of the Ni-CNT coatings are irrelevant to the CNT concentration in the solution, the current density, and current mode, implying poor adhesion of CNTs to Ni matrix. With increasing the CNT content in the coating, the corrosion resistance of the Ni-CNT composite coating becomes inferior due to the porous microstructure.

Study of the Influence of the Electrolysis Parameters on Mn-Zn, Mn-Cu and Mn-Cu-Zn Alloys Coatings from Electrolytes Containing Complexing Ligands

The process of obtaining of high quality Mn-Zn, Mn-Cu and Mn-Cu-Zn alloy coatings from complexing ligands--citrate, EDTA （ethylene diaminetetra acetic acid） and nitrilotriacetic acid solutions was studied. Factors affecting stability of solutions containing ligand or ligands and influence of electrolysis parameters： electrolyte composition, pH, cathodic current density on chemical composition of the obtained coatings, on their current efficiency, morphology and structure were investigated.

Morphologies and corrosion resistances of electroless Ni-P coated nanoporous coppers

In order to improve the corrosion resistance of nanoporous coppers （NPCs）, the electroless Ni-P coated NPCs were prepared in plating solutions with different pH values （5, 8, 11） and complexing agent （actic acid, citric acid）. The morphologies and cor- rosion resistances of the as-prepared samples were investigated. The results showed that the double complexing agent com- posed of lactic acid and citric acid is relatively suitable for preparing the Ni-P coated NPC with three-dimensional continuous interpenetrating ligament-channel structures, and the uniform ligaments and nanoporous channels could be obtained at pH8. The Ni-P coated NPC showed higher corrosion potentials than NPC in H2S04, NaOH and NaC1 corrosion solutions.

One-step synthesis of fluorescent hydroxyls-coated carbon dots with hydrothermal reaction and its application to optical sensing of metal ions

Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot of hydroxyls, possessed properties of good water-solubility, anti-photobleaching, salt tolerance, and low cytotoxicity, and had a fluorescence quantum yield (QY) of about 5.5%. The fluorescence of the hydroxyls-coated CDs could be selectively quenched by metal ions such as Cr3+, Al3+ and Fe3+, which is because these metals can easily combine with the hydroxyl groups on the surface of CDs and induce aggregation of hydroxyls-coated CDs. Experiments showed that the quenching of Cr3+ had a Sterm-Volmer constant of 1.03 × 107 M-1 with a liner range of 1.0-25.0 μM and detection limit of 60 nM (3σ).

光致变色纺织品的制备方法及其应用

光致变色化合物具有响应速度快、操作简单等特点,可实现纺织品从“静态”到“动态”的转变,在民用功能纺织品中受到广泛关注。按照点开环-闭环、氧化还原、顺反异构、质子转移等不同途径介绍了光致变色织物的变色机理。详述了光致变色纺织品的制备方法和研究进展,简述了其应用前景,并指出溶液-凝胶涂层技术是极具应用前景的一种制备光致变色纺织品的方法。