阳离子分散松香施胶剂施胶性能的研究

阳离子分散松香施胶剂（ＣＤＲＳ）作为松香系列施剂的新型换代产品之一,其施胶性能是评价其应用价值的重要依据。本研究对自制的ＣＤＲＳ在不同条件下的施胶效果进行了试验并与现有的商品松香施胶剂进行了对比。中碱性条件一的施胶试验结果表明,ＣＤＲＳ相对阴离子分散松香胶而言,消耗助留剂硫酸铝的量约低５０％,而且在ＰＨ６．５－７．５条件下具有较好的施胶效果。     

离子选择电极法测定大田土壤中有效钾和植物组织中钾含量的研究

用阳离子交换树脂膜法提取土壤中有效钾,用离子选择电极法直接测定提取液中钾含量,其测定值与原子吸收测定值间呈极显著正相关（ｒ＝０．９５～０．９９,ｎ＝１８）。油菜新鲜叶片汁液中的钾含量用离子选择电极法直接测定,叶片组织中钾含量与土壤中有效钾含量及油菜干物全钾含量均呈显著正相关。     

基于核酸适配体的阳离子聚合物聚集纳米金比色法检测水中睾酮

利用核酸适配体对睾酮特异性识别功能以及阳离子聚合物PDDA(poly dimethyl diallyl ammonium chloride,PDDA)聚集纳米金特性,建立了一种高灵敏度、高特异性测定睾酮的定量方法。在最优实验条件[10 mmol/L PB缓冲溶液(pH 7.4),孵育温度25℃,6nmol/L PDDA,6nmol/L睾酮核酸适配体]下,体系吸光度比值A_(650)/A_(520)与睾酮浓度C呈良好的线性关系,决定系数R2为0.995。该方法可检测睾酮浓度范围为2.27nmol/L~1.8μmol/L,最低检测限为2.27nmol/L,将本方法应用于检测自来水睾酮含量,加标回收率为99.81%~105.04%。本方法具有检测范围广、成本低、操作简便、检测灵敏等优点,具有良好实际应用前景。     

纳米纤维素复合物对再生纸性能的影响

以阳离子淀粉(CS)为增强剂,并与纳米纤维素(NC)组成二元增强体系,研究其对旧瓦楞纸箱(OCC)再生纸的增强效果.通过考察阳离子淀粉添加量对旧瓦楞纸箱再生纸主要性能的影响,筛选出合理的用量;在此基础上,通过添加纳米纤维素组成二元增强体系,进一步考察其添加量对旧瓦楞纸箱再生纸主要性能的影响.借助傅里叶红外光谱(FTIR...     

模拟氮沉降对内蒙古典型草地土壤pH和电导率的影响

陆地生态系统氮沉降增加可导致土壤酸化,从而可能造成土壤生态系统结构和功能的退化。依托内蒙古典型草地设置的模拟氮沉降试验,研究了连续6年9个氮添梯度(0、1、2、3、5、10、15、20、50 g m~(-2)a~(-1)),2个氮添加频次(一年两次或一月一次)及2种管理方式(封育或刈割)等4种模式对土壤p H和电导率的影响。结果表明,4种模式下氮添加量3 g m~(-2)a~(-1)以下4个处理间的土壤p H无显著差异,在氮添加量为20 g m~(-2)a~(-1)(与我国粮食作物年施氮量接近)时,土壤p H分别比对照平均降低了1.1~1.9个单位;封育一年两次添加氮素在添加量5 g m~(-2)a~(-1)以上时土壤p H显著下降,而封育每月一次添加氮素在添加量20 g m~(-2)a~(-1)以上时,土壤p H才出现显著下降的现象。4种模式下土壤p H与土壤阳离子交换量及土壤交换性钙呈极显著正相关,说明高量氮添加促进了土壤中盐基离子的耗竭。高量氮添加(50 g m~(-2)a~(-1))显著增加了土壤EC值;除封育每月一次添加氮素处理外,氮添加10 g m~(-2)a~(-1)以下各处理间的土壤电导率(EC)无显著差异;土壤EC值与土壤硝态氮含量呈极显著正相关。研究结果将为我国北方半干旱草地土壤酸化的量化表征及氮素管理提供数据支撑。     

科尔沁草甸生态系统净碳交换特征及其驱动因子

以2013年10月-2014年9月连续观测的CO₂通量数据为基础,分析了科尔沁草甸生态系统净碳交换量(NEE)的时间变化特征及其驱动因素。结果表明,NEE日变化季节差异明显,生长季变化幅度大,净CO₂日吸收速率7月>8月>9月>6月>5月;生长季内,NEE主要受控于叶面积指数和光合有效辐射。NEE与光合有效辐射(PAR)之间的关系可用直角双曲线方程来描述,拟合得到的表观初始光能利用率α为0.0015 μmol CO₂/μmol PAR,最大光合速率P_max为0.65 μmol CO₂/(m²·s)。叶面积指数(LAI)对NEE的影响可由分段函数表示,当LAI>3.08时,表现为渐进饱和型,且LAI越大NEE对PAR的响应越明显;当高饱和水汽压差(VPD)在1.5~2.0 kPa时,光合作用开始降低,NEE明显受到VPD值的抑制;短暂强降雨(累计降雨量>40 mm/d)对昼间NEE有一定的抑制,而持续低强度降雨(降雨时长>15 h)对夜间NEE存在激发作用;夜间NEE随土壤温度呈指数增长,温度敏感系数(Q₁₀)为2.63。     

Effects of artificially cultivated biological soil crusts on soil nutrients and biological activities in the Loess Plateau

Biological soil crusts （BSCs） play an important role in the early succession of vegetation restoration in the Loess Plateau, China. To evaluate the effects of artificially cultivated BSCs on the soil surface micro-envir- onment, we obtained natural moss crusts and moss-lichen crusts from the Loess Plateau of Shaanxi province, and subsequently inoculated and cultivated on horizontal and sloping surfaces of loess soil in a greenhouse. The chemical and biological properties of the subsoil under cultivated BSCs were determined after 10 weeks of cul- tivation. The results indicated that BSCs coverage was more than 65% after 10 weeks of cultivation. Moss crust coverage reached 40% after 5 weeks of cultivation. Compared with the control, soil organic matter and available nitrogen contents in moss crust with the horizontal treatments increased by 100.87% and 48.23%, respectively; increased by 67.56% and 52.17% with the sloping treatments, respectively; they also increased in moss-lichen crust with horizontal and sloping treatments, but there was no significant difference. Available phosphorus in cultivated BSCs was reduced, soil pH was lower and cationic exchange capacity was higher in cultivated BSCs than in the control. Alkaline phosphatase, urease and invertase activities were increased in artificially cultivated BSCs, and alkaline phosphatase activity in all cultivated BSCs was obviously higher than that in the control. Numbers of soil bacteria, fungi and actinomycetes were increased in the formation process of cultivated BSCs. These results indicate that BSCs could be formed rapidly in short-term cultivation and improve the mi- cro-environment of soil surface, which provides a scientific reference for vegetation restoration and ecological reconstruction in the Loess Plateau. China.     

森林土壤表层土的生态毒性评估

A series of 9 soil samples were taken at a timber treatment site in SW France where Cu sulphate and chromated copper arsenate (CCA) have been used as wood preservatives (Sites P1 to P9) and one soil sample was collected at an adjacent site on the same soil type (Site P10). Copper was a major contaminant in all topsoils, varying from 65 (Soil P5) to 2600 mg Cu kg^-1 (Soil P7), exceeding background values for French sandy soils. As and Cr did not accumulate in soil, except at Site P8 (52 mg As kg^-1 and 87 mg Cr kg^-1) where CCA-treated posts were stacked. Soil ecotoxicity was assessed with bioassays using radish, lettuce, slug Arion rufus L., and earthworm Dendrobaena octaedra (Savigny). There were significantly differences in lettuce germination rate, lettuce leaf yield, radish root and leaf yields, slug herbivory, and earthworm avoidance. An additional bioassay showed higher negative impacts on bean shoot and root yields, Rhizobium nodule counts on Bean roots, and guaiacol peroxidase activity in primary Bean leaves for soil from Site P7, with and without fertilisation, than for soil from Site P10, despite both soils having a similar value for computed free ion Cu²⁺ activity in the soil solution (pCu²⁺). Beans grown in soil from Site P7 that had been fertilised showed elevated foliar Cu content and phytotoxic symptoms. Soils from Sites P7 (treatment plant) and P6 (storage of treated utility poles) had the highest ecotoxicity, whereas soil from Site P10 (high organic matter content and cation exchange capacity) had the lowest. Except at Site P10, the soil factor pCu²⁺ computed with soil pH and total soil Cu could be used to predict soil ecotoxicity.     

阳离子半纤维素的制备及对纸张的增强作用研究

以三倍体毛白杨硫酸盐法制浆造纸过程中预提取出来的半纤维素为原料,在乙醇-水介质中制备季铵型阳离子半纤维素.讨论了醚化剂用量、NaOH用量、反应温度、反应时间等对取代度的影响.结果表明,最佳合成条件为:氢氧化钠用量6%、醚化剂用量30%、乙醇用量50%、反应温度60℃、反应时间3.0h,在此条件下可以得到取代度为0.034的阳离子半纤维素.采用红外光谱对改性前后半纤维素的结构变化进行表征,并使用所合成的阳离子半纤维素作为纸张增强剂,研究了它对纸张的增强作用.研究发现,当阳离子半纤维素的加入量为0.7%(取代度为0.034)时,可显著提高纸张的强度.     

变应原体外检测对咳嗽变异性哮喘的诊断意义

目的了解应用变应原体外检测系统进行变应原筛查和血清嗜酸细胞阳离子蛋白（ECP）测定对咳嗽变异性哮喘诊断的意义。方法选择CVA患儿32例（CVA组）、支气管哮喘（CVA除外）患儿29例（支气管哮喘组）、肺炎患儿30例（肺炎组）、健康儿童22例（正常对照组）,应用变应原体外检测系统进行变应原过筛试验及各组血清嗜酸细胞阳离子蛋白（ECP）水平测定。结果变应原过筛实验阳性率：CVA组75.0%,支气管哮喘组79.3%,肺炎组10.0%,正常对照组13.6%,CVA组与支气管哮喘组比较差异无统计学意义（P＞0.05）,而CVA组与肺炎组及正常对照组比较差异有统计学意义（P＜0.01）。血清ECP水平：CVA组为（17.50±6.98）μg/L,支气管哮喘组为（16.55±3.56）μg/L,肺炎组为（5.62±3.66）μg/L,正常对照组为（4.18±2.14）μg/L,CVA组与支气管哮喘组比较差异无统计学意义（P＞0.05）,而CVA组与肺炎组及正常对照组比较差异有统计学意义（P＜0.01）。结论变应原体外检测系统进行过敏原筛查试验及ECP测检对诊断咳嗽变异性哮喘有重要意义。