Detection of phosphorus species in sediments of artificial landscape lakes in China by fractionation and phosphorus-31 nuclear magnetic resonance spectroscopy

Phosphorus (P) pollution in the sediments of seven artificial landscape lakes was studied via fractionation and phosphorus-31 nuclear magnetic resonance ((31)P NMR) spectroscopy. The lake sediments accumulated significant amounts of P from supplementation with reclaimed water and from runoff from the golf course lawns. The differences in total sediment P among lakes were correlated to the varied pollution extent from the lawns. One striking feature of the artificial lake sediments was the insufficiency of NaOH-extracted Al, which plays an important role in avoiding internal P release during anoxia. Another characteristic was the dominance of orthophosphate in the NaOH-EDTA extractants of the sediments, due to the heavy external P pollution. Phytate, considered prevalent in many soils and lake sediments, as well as polyphosphates and phosphonates which have appeared in some natural lake sediments, was not detected. The rank order of present biogenic P species was monoester-P>DNA-P>pyrophosphate>lipid-P.     

局部断层场地对平面SV波的散射

借助Wolf的土层和半空间精确动力刚度矩阵及斜线荷载的格林函数,利用间接边界元法在频域内求解了局部断层场地对SV波的散射,着重分析了破碎带较窄断层两侧围岩动力响应的基本规律,以及场地动力特性对散射的影响.研究表明,破碎带断层对SV波有显著的影响,即使破碎带很窄,也可以对SV波产生很大的放大作用;层状场地的动力特性对放大作用有显著的影响.     

南京北郊气溶胶散射特性观测研究

南京北郊是重工业区,空气污染严重。该文利用浊度仪对大气气溶胶散射系数进行了四季观测,研究了该区气溶胶散射系数、后向散射比、质量散射系数及散射系数与能见度的关系,结果表明,观测期间散射系数波动较大,平均值为344.84 Mm^-1,标准差为215.99 Mm^-1,散射系数季节差异明显,主要受气象条件和外界污染排放的影响;后向散射比平均值为0.139,春季变化剧烈,夏、秋、冬季在波动中缓慢上升,大气中细粒子污染严重且含量有增加的趋势;散射系数与PM_2.5质量浓度相关系数达到0.91,质量散射系数平均值为1.87m²/g;散射系数与能见度之间存在-0.66的相关性,两者呈负幂函数关系。     

Detailed characterization of polar compounds of residual oil in contaminated soil revealed by Fourier transform ion cyclotron resonance mass spectrometry

Effects of remediation technologies on polar compounds of crude oil in contaminated soils have not been well understood when compared to hydrocarbons. In this study, ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the changes in NSO polar compounds of crude oil and residual oil after long-term natural attenuation, biostimulation and subsequent ozonation following biostimulation of contaminated soils. N₁ and O₁ species, which were abundant in the crude oil, were selectively biodegraded, and species with higher double bond equivalent values and smaller carbon numbers appeared to be more resistant to microbial alteration. O₂-O₆ species were enriched by biodegradation and contained a large number of compounds with a high degree of unsaturation. Ozone could react with a variety of polar compounds in residual oil after biodegradation and showed high reactivity with polar species containing aromatic or multi-aliphatic rings, including the residual N₁ and O₁ species, naphthenic acids and unsaturated O₃-O₆ compounds. Fatty acids and O₃-O₈ species dominated by saturated alkyl compounds were resistant to ozonation or the primarily incomplete ozonation products. Principal component analysis of identified peaks in the FT-ICR MS spectra provided a comprehensive overview of the complex samples at the molecular level and the results were consistent with the detailed analysis. Taken together, these results showed the high complexity of polar compounds in residual oils after biodegradation or ozonation in contaminated soil and would contribute to a better understanding of bioremediation and ozonation processes.     

电动振动台台面加速度失真度的分析

通过对影响电动振动台失真度因素的定性分析，得出影响失真度的理论依据，提出降低电动振动台台面加速度失真度的措施，供设计电动振动台及使用电动振动台者参考。     

Surface characterization of metal oxides-supported activated carbon fiber catalysts for simultaneous catalytic hydrolysis of carbonyl sulfide and carbon disulfide

The sol–gel method was used to synthesize a series of metal oxides-supported activated carbon fiber (ACF) and the simultaneous catalytic hydrolysis activity of carbonyl sulfide (COS) and carbon disulfide (CS₂) at relatively low temperatures of 60°C was tested. The effects of preparation conditions on the catalyst properties were investigated, including the kinds and amount of metal oxides and calcination temperatures. The activity tests indicated that catalysts with 5 wt.% Ni after calcining at 400°C (Ni(5)/ACF(400)) had the best performance for the simultaneous catalytic hydrolysis of COS and CS₂. The surface and structure properties of prepared ACF were characterized by scanning electron microscope-energy disperse spectroscopy (SEM-EDS), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), carbon dioxide-temperature programmed desorption (CO₂-TPD) and diffuse reflectance Fourier transform infrared reflection (DRFTIR). And the metal cation defects were researched by electron paramagnetic resonance (EPR) method. The characterization results showed that the supporting of Ni on the ACF made the ACF catalyst show alkaline and increased the specific surface area and the number of micropores, then improved catalytic hydrolysis activity. The DRFTIR results revealed that -OH species could facilitate the hydrolysis of COS and CS₂; -COO and -C–O species could facilitate the oxidation of catalytic hydrolysate H₂S. And the EPR results showed that high calcination temperature conditions provide more active reaction center for the COS and CS₂ adsorption.