蚕沙基多孔炭表面氧化改性对农药噻虫嗪吸附及缓控释影响

选用桑蚕废弃物蚕沙为炭源,通过炭化活化的方式获得了一种高比表面的中微双孔道生物炭材料SCSE,并采用不同氧化剂对其表面氧化处理以调控材料孔径和表面积对农药噻虫嗪分子的吸附作用力,以实现SCSE材料对农药噻虫嗪的缓控释,并系统研究了氧化改性后材料的比表面积、孔径和表面基团性质的变化对材料吸附噻虫嗪的热力学和动力学平衡以及噻虫嗪的释放动力学等性能的影响。结果表明：SCSE孔隙结构发达,其BET比表面和孔容分别为1290.95 m²/g和0.690 cm³/g;在室温下,该材料对噻虫嗪分子的吸附容量达到560 mg/g。噻虫嗪在四种SCSE上的释放动力学可分为快速持续释放过程和慢速释放过程两个过程,其中快速持续释放过程的释放动力学常数约是慢速释放过程的29～34倍;其中硝酸改性后的SCSE-HN对噻虫嗪的释放比例最大,释放速度最快。本实验所获得的四种SCSE材料对噻虫嗪的释放均表现出长效释放效力。按照一般农作物的需药量,该吸附剂只要按照0.5 g/（d·m²）的投入量便能很好地对农作物进行长效的虫害防治（>40 d）。     

β-咔啉类杂环胺模型体系反应产物相关性质的研究

为深入了解美拉德反应与其伴生危害物之间的关系,以色氨酸、葡萄糖和肌酐为反应底物建立β-咔啉类杂环胺美拉德反应模型体系,在160、180、200℃条件下分别反应不同时间,分析各体系β-咔啉类杂环胺及理化指标的变化规律并对其进行相关性分析.结果 表明:随着反应时间延长和反应温度升高,β-咔啉类杂环胺Norharman和Ha...     

压水堆技术后续发展的思考

针对压水堆核电技术后续发展的问题,本文分析了压水堆技术在安全性、环境友好性、经济性和运行灵活性等方面面临的挑战.基于文献调研和工程实践经验,总结了压水堆技术近期可行的发展方向,这些发展方向包括了先进燃料、不调硼负荷跟踪、优化的能动与非能动安全系统等.在远期发展方面,可以将研究重点从安全系统的优化提升转移到消除或降低事故...     

戊二醛铬复鞣对猪正面服装坯革性能及微观结构的影响

本文进行了戊二醛铬结合复鞣的一系列对比试验和复鞣坯革的感观鉴定,并用扫描电镜观察了复鞣坯革的纤维结构,为合理选择戊二醛用量和改善猪皮服装革质量提供了科学依据。     

国产硅藻土研究进展及其新应用

简介国产硅藻土结构，吸附性质等方面研究的进展，以及近年硅藻土的一些新应用。     

缩放管内插双扭带复合强化传热的数值模拟(英文)

The paper presents a 3D numerical simulation of turbulent heat transfer and flow characteristics in converging-diverging tubes(CDs) and converging-diverging tubes equipped with twin counter-swirling twisted tapes(CDTs).The effects of Reynolds number(Re 10000-20000),pitch length(P 11.25,22.5 mm),rib height(e 0.5,0.8,1.1 mm),pitch ratio(δ1:8,5:4,8︰1),gap distance between twin twisted tapes(b 0.5,4.5,8.5 mm) and tape number(n 2,3,4,5,6) on Nusselt number(Nu),friction factor(f) and thermal enhancement factor(η) are investigated under uniform heat flux conditions,using water as working fluid.In order to illustrate the heat transfer and fluid flow mechanisms,flow structures in CDs and CDTs are presented.The obtained results reveal that all geometric parameters have important effects on the thermal performance of CD and CDT,and both CD and CDT show better thermal performance than plain tube at the constant pumping power.It is also found that the increases in the Nusselt number and friction factor for CDT are,respectively,up to 6.3%-35.7% and 1.75-5.3 times of the corresponding bare CD.All CDTs have good thermal performance with η greater than 1 which indicates that the compound heat transfer technique of CDT is commendable for the maximum enhanced heat transfer rate.     

异养硝化菌株W1的分离和表征(英文)

In a high concentration substrate medium, a heterotrophic bacterium with high removal efficiency of ammonium, named W1, was isolated from activated sludge of coking wastewater treatment facility. The bacterium was Gram-negative, rod-shaped, and identified preliminarily as Alcaligenes sp. according to its morphological and physiological properties and its 16S rRNA gene sequence analysis. In the high concentration ammonium medium (400 mg·L 1 4 NH -N), the effects of C source, N source, C/N ratio and initial pH of medium on ammonium removal were investigated in order to determine the optimal condition for strain W1. The maximum ammonium removal was around 95% in 4 days in an improved medium. The production of N 2 gas was examined in a closed system that was full of pure oxygen at the beginning. N 2 gas was detected in the system after 4 days of cultivation, which further testified that strain W1 has heterotrophic nitrification and aerobic denitrification abilities simultaneously.     

Physicochemical characteristics,antioxidant capacity and thermodynamic properties of purple-fleshed potatos dried by radio frequency energy

Abstract

The impacts of using radio frequency (RF) energy to dry purple-fleshed potatoes were investigated and compared to infrared radiation (IR) and microwave (MW) drying techniques. The gelatinization rate, color, flavor, morphological, and structural characteristics, thermodynamic properties, as well as antioxidant capacity were examined. The results indicated that the drying time of RF (70?min) and MW (21?min) were shorter than IR (105?min). The gelatinization ratio of MW, RF, and IR were 94.4?±?2.0, 88.3?±?1.4, and 64.5?±?1.1%, respectively. The degree of crystallization of purple-fleshed potato powder decreased with all three drying methods. RF-dried potatoes were able to retain higher polyphenols (loss rate: 4.3%), total anthocyanin (3.7%), and total flavonoid content (35.1%), whereas IR showed the lowest retention. The content of polyphenols also decreased significantly. Furthermore, after RF heating, the scavenging of free radicals was higher compared to MW and IR.     

Response of Nd3+ and Sm3+ precipitating into rhabdophane and the leaching mechanism of associated monazite ceramics

Rhabdophane has been considered an important permeable reactive barrier to isolate groundwater radionuclides, and evaluating its precipitation response to different species of radionuclide in acid solutions is critical. In this work, the effects of pH values on the precipitation behavior of Nd³⁺ and Sm³⁺ into La-rhabdophane are systematically investigated. Some specific issues such as ions removal, precipitation reaction kinetics, and crystal growth affected ions incorporation are discussed in detail, along with uncovering the veil of the Ln (La, Nd, and Sm) leaching mechanism of associated La_0.666Nd_0.167Sm_0.167PO₄ monazite ceramic based on dissolution experiments and density functional theory. The results reveal that Nd³⁺ and Sm³⁺ can be removed more than 98% in pH = 1 solution within 12 h, whereas uneven precipitation process to form unexpected stoichiometric ratio of rhabdophane has been observed in 30–50 nm short crystal. Grain growth effects based on spark plasma sintering can contribute to homogenize the materials composition with obtaining La_0.666Nd_0.167Sm_0.167PO₄ monazite ceramics. Furthermore, the binding energy of Ln–O in (1 0 0) surface of monazite plays an important role in controlling the leaching stability of Ln³⁺, associated with the leaching activities are energetically favorable in the order of La > Nd > Sm for La_0.666Nd_0.167Sm_0.167PO₄ monazite.     

Solution‐reprocessable microporous polymeric adsorbents for carbon dioxide capture

Solution‐processable microporous polymers are promising materials for CO₂ capture because of their low synthetic cost and high processability. In this work, we for the first time systematically evaluate the feasibility of two microporous polymers, namely PIM‐1 and its hydrolyzed form hPIM‐1, as adsorbent materials for postcombustion CO₂ capture. By conducting ternary CO₂/N₂/H₂O breakthrough experiments, PIM‐1 demonstrates several promising features: moderate CO₂ working capacity, low water vapor uptake capacity, good moisture resistance, and easy regeneration process. In addition, we have pioneeringly studied the multiple‐cycle CO₂ adsorption–desorption induced relaxation effect on soft PIM‐1 polymers. Through a simple dissolution–precipitation approach, PIM‐1 can restore its BET surface area, CO₂ uptake capacity, and pore‐size distribution. The solution reprocessability of PIM‐1 demonstrated in this study distinguishes it from other rigid adsorbents and thus offers a new insight for the future design of economically‐viable and facilely regenerable adsorbents. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3376–3389, 2018