不同比色皿对近红外光谱法检测水质酸度的影响及校正分析

为减小不同比色皿对近红外光谱测量结果的影响,提高水质酸度定量分析模型的预测精度,探讨了正交信号校正(OSC)用于不同比色皿的光谱背景干扰的去除效果。用两个同一批次的石英比色皿对32个不同pH的水样装样,采集近红外光谱数据,采用OSC对原始光谱进行预处理。比较OSC预处理前后两组光谱间的差异,并建立了水质酸度的偏最小二乘(PLS)定量分析模型,分析了光谱差异对模型预测精度的影响。结果表明:经OSC预处理后,两组光谱的平均差异值由0.0042降低至0.0013,光谱校正率达90%;与原始光谱建立的PLS模型相比,基于OSC预处理后的光谱建立的PLS模型的预测精度显著提高,预测均方根误差差值由0.912降低至0.205,相关系数差值由0.364降低至7.00×10^(-3),二者分别减小了78%和98%。

Effect of Electrochemical Treatment in Aqueous Ammonium Bicarbonate on Surface Properties of PAN-based Carbon Fibers

The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.

Changes in Plasma Osmolality, Cortisol and Amino Acid Levels of Tongue Sole(Cynoglossus semilaevis) at Different Salinities

A serial of salinity transferring treatments were performed to investigate the osmoregulation of tongue sole(Cynoglossus semilaevis). Juvenile tongue sole were directly transferred from a salinity of 30 to 0, 10, 20, 30, 40 and 50. Blood sampling was performed for each treatment after 0, 1, 6 and 12 h, as well as after 1, 2, 4, 8, 16 and 32 d. The plasma osmolality, cortisol and free amino acids were assessed. Under the experimental conditions, no fish died after acute salinity transfer. The plasma cortisol level increased 1 h after the abrupt transfer from a salinity of 30 to that of 0, 40 and 50, and decreased from 6 h to 8 d after transfer. Similar trends were observed in the changes of plasma osmolality. The plasma free amino acids concentration showed a ‘U-shaped' relationship with salinity after being transferred to different salinities for 4 days. More obvious changes of plasma free amino acid concentration occurred under hyper-osmotic conditions than under hypo-osmotic conditions. The concentrations of valine, isoleucine, lysine, glutamic acid, glycine, proline and taurine increased with rising salinity. The plasma levels of threonine, leucine, arginine, serine, and alanine showed a ‘U-shaped' relationship with salinity. The results of this study suggested that free amino acids might have important effects on osmotic acclimation in tongue sole.

A study on Cr(Ⅵ)reduction from aqueous solutions by bauxite

The reduction of Cr（Ⅵ） in aqueous solution by using bauxite ore was investigated.Experimental results for Cr（Ⅵ）reduction in aqueous solution depending on some factors such as time,sulfuric acid amount,bauxite dosage,initial Cr（Ⅵ）concentration,formic acid concentration,daylight and temperature were presented.The obtained results show that sulfuric acid amount,bauxite dosage and initial Cr（Ⅵ） concentration of solution are most effective parameters on the reduction process.Also,it has been found that the 60 g/L of bauxite dosage is sufficient to reduce up to 100% of Cr（Ⅵ） from acidic solution under the condition of low initial Cr（Ⅵ） mass concentrations such as 10 mg/L.The reduction reaction is completed within 30 min at 25 ℃ under the experimental conditions：bauxite dosage of 60 g/L,amount of sulfuric acid 40-60 stoichiometric and initial mass concentration of Cr（Ⅵ）,10 mg/L.It was determined that reduction percentage is decreasing with increasing initial Cr（Ⅵ） concentration.The chemical oxygen demand of bauxite ore was found to be 26 mg COD/g.

Effect of Mineral Acids on Rooting Response of Aging Mung Bean （Phaseolus aureus Roxb,） Cuttings via Indole Acetic Acid Level

The influence of nitric acid （HNO3） as a strong mineral acid on rooting response of fresh mad aging mung bean cuttings has been studied on the level of Indole-3-Acetic Acid （IAA）. The data revealed significant increase in rooting response of fresh cuttings treated with （0.0001% and 0.1%） concentrations of HNO3 solution, significant increase in rooting response of aged cuttings （for 3 days in d/H20） with （0.0001% and 0.01%） concentration of HNO3 solution and highly significant increase in rooting response of aged cuttings （for 3 days in HNO3 solution） with （0.0001%） concentration, while highly concentration （0.5%） revealed highly significant decrease in rooting response compared to control （d/H20）. Quantitative estimation oflAA by spectrophotometric method as indicators for oxidative processes that occurrence during aging phenomenon verified a highly significant increase of IAA content in hypocotyles of fresh and aged cuttings in optimal concentration of HNO3.

Survey on Gamasyab River Water Quality in Nahavand Township, Iran

Gamasyab River, which is the biggest river of Hamadan Province, is sourced from Karstic Springs in Nahavand Township Southern Mountainous Region and supplies a major part of water needs of the region. In this research seasonal variation of water quality and also the degree of pollution related to Gamasyab River water have been assessed. First the general status of the river was studied and four sampling stations were determined. In this research, the quality of river water including Dissolved Oxygen （DO）, five days Biochemical Oxygen Demand （BOD）5, Chemical Oxygen Demand （COD）, Nitrate, phosphate, temperature, Total Hardness（TH）, Total Suspended Solid （TSS）, Total Dissolved Solid （TDS） and PH have been determined and assessed on a monthly basis within a five years period. The results were reported as seasonally and presented using statistical tables and graphs. These results showed that Nitrate concentration in Gamasyab River is strongly depending on distance from Gamasyab spring. By increasing the distance from Gamasyab spring, nitrate concentration increased. The amount of DO in the river water is stable in each station within the year. Air temperature changes have had no effect in the amount of DO. Therefore, it is recommended that the river pollution control plans be implemented more serious than before, non point source pollution related to agricultural activities be managed and prevent from pouring untreated rural wastewaters to the mentioned river.

Studies on Physiological Radiation Spectrum and Fruit Quality of Sweet Cherry in Different Canopies

[ Objective] The physiological radiation spectrum and fruit quality in different canopies of sweet cherry tree were studied. [ Method] Opti- cal fiber spectrum was applied to determine the physiological radiation spectrum in different canopies of sweet cherry tree. The fruit quality in differ- ent canopies was determined. [Result] The results showed that from the top part to the lower part and from the outer part to inner part of sweet cherry canopy, Me physiological radiation intensity and ratio of short wave light reduced significantly, while ratio of long wave light increased. Fruit mass, Vc, TSS and total sugar content were significantly decreasing, while organic acid content increasing, but the fruit edible percent was similar. Furthermore, the physiological radiation intensity was strong, fruit mass, TSS, Vc and total sugar content increased, but organic acid content re- duced. [ Condusion] The higher and bigger canopy of sweet cherry, the poor and lower physiological radiation intensity, photosynthesis accumula- tion and fruit quality. The study provided theoretical foundation and reference for the trim of sweet cherry.

Dynamics of liquid-phase catalytic oxidation of hydrogen sulfide removal in rural biogas

Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and sulfur capacity of the composite solution was about 3 g/L.The results show that purification efficiency was affected by catalyst addition,pH,experimental temperature,and sulfur capacity.The parameters effects on catalytic oxidation were studied,and the optimized conditions were that Fe3+ concentration 0.08 mg/L,reaction temperature 70°C,pH 9.0,with a absorption solution volume of 50 mL,a gas flow rate 200 mL/min,and H2S mass concentration of 1.58-2.02 mg/m3.

Assessment of the Impact of Developmental Activities on the Estuarine Environments of Mandovi and Zuari Rivers of Goa along the West Coast of India

Physico-chemical and biological data on water and sediments were collected from Mandovi and Zuari Rivers of Goa along the central west coast of India from 2007 to 2008 to understand the impact of developmental activities on the riverine environments. Factor analysis of the data segregated over high and low tides indicated a total of 6 factors each explaining 91% of variance during high tide and 84% of variance during low tide in Mandovi River. In Zuari River, a total of 6 factors explained 83% of variance during high tide and 4 factors explained 78% of variance during low tide. Factor analyses showed the dominance of nitrite and nitrate in Mandovi and of lead and mercury in Zuari. Higher inputs of anthropogenic ammonia and phenols associated with some phosphate were found in both these rivers. Water quality index （WQI） studies showed increasing overall index of pollution （OIP） values especially in the upstream of Zuari River, suggesting slightly polluted water. Increasing developmental activities along the banks of these rivers introduce domestic and anthropogenic nutrients and trace metals in their estuarine region, which flush out to the sea as per tidal currents, which otherwise can hamper the natural environments of these two rivers.

Enhancement of solubility and mass transfer coefficient of salicylic acid through hydrotropy

This study deals with the effect of hydrotropes on the solubility and mass transfer coefficient of salicylic acid. The solubility and mass transfer studies were performed using the hydrotropes, i.e., sodium acetate, sodium salicylate, citric acid, and urea at concentrations of 0-3.0 mol/L and system temperatures of 303-333 K. It was found that the solubility and mass transfer coefficient of salicylic acid increases with increase in hydrotrope concentration and also with system temperature. All hydrotropes used in this work showed an enhancement in solubility and mass transfer coefficient to different degrees. The maximum enhancement factor values were determined for all hydrotropes used in this study. The highest value was 28.08 for solubility studies and 10.42 for mass transfer studies. The performance of hydrotropes was measured in terms of the Setschenow constant （Ks）. The highest value observed was 0.696.