印染污泥干燥过程中挥发分冷凝液的研究

对某印染废水处理厂的污泥进行模拟干燥处理,以产生的挥发分冷凝液为研究对象来考察干燥温度和干燥程度对印染污泥干燥过程中污染物产生的影响。随着干燥温度的升高,挥发分冷凝液COD、NH3-N含量均升高,且在140℃至160℃时升高较快,分别为177～262 mg/L,100～130 mg/L,而pH较稳定。污泥含水率从65%干燥至5%时,挥发分冷凝液的COD、NH3-N含量升高不明显,分别为176～190 mg/L、85～105 mg/L。干燥温度比干燥程度更能影响印染污泥干燥过程中污染物的产生。     

Salt poisoning blindness in wistar rat,rabbit, and pig

The objective of this study was to determine the ocular changes leading to blindness following different salt concentration consumption in Wistar rats. Test groups consumed 1, 2, 3, 3.5, or 4% salt concentration respectively as potable water, while the control group used tap water. Ophthalmic examinations with a slit-lamp and fundus camera were performed. Lack of eye response to light and manual stimuli were considered as blindness criteria. Similar experimental conditions were performed in pigs and rabbits. Short duration consumption of 1 or 2% salt concentrations did not produce any detectable ocular signs, whereas long duration consumption of 2% salt concentration induced prominent ocular signs. After 3–4 days of consuming 3% and higher salt concentrations, retinal and vitreous hemorrhages, posterior vitreous detachment PVD, and retinal detachment were observed. The following ocular changes included conjunctivital injection, cornea and lens opacities, swelling of the optic disc, blindness, vitreous collapse, and finally phthisis bulbi. Salt poisoning led to hypernatremia and hyperosmolarity. Due to hyperosmolarity, the vitreous lost some of its fluid contents and vitreous shrinkage resulted in vascular damage, retinal and vitreous hemorrhage, PVD, and retinal detachment. In addition, conjunctivitis, corneal and lens opacities, swelling of the optic disc, blindness, vitreous collapse, and finally phthisis bulbi was evident.     

A sensitive method for selective determination of vanadium species by dispersive liquid–liquid microextraction (DLLME) with spectrophotometric detection

A simple, fast, and low-cost analytical procedure was developed for trace-level determination of inorganic vanadium species by dispersive liquid–liquid microextraction in combination with spectrophotometry. Vanadium in pentavalent form, V(V), was quantitatively extracted into organic phase as 4-(2-pyridylazo)-recorcinol (PAR) complex in the presence of N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB) as counter-ion. Vanadium (IV) was masked with 1,2-diaminocyclohexanetetraacetic acid to allow speciation analysis. Total vanadium was determined after oxidation of V(IV) to V(V). The main factors affecting preconcentration and spectrophotometric detection of vanadium species such as pH, concentration of PAR and CTAB, the type and volume of the extraction, and disperser solvents were optimized. The limit of detection and enhancement factor obtained under optimum conditions were found to be 0.06 μg L^?1 and 98, respectively. Relative standard deviations for V(IV) and V(V) at 3.0 μg L^?1 were less than 2.4%. The presented procedure was applied to environmental water samples for selective determination of vanadium species. Moreover, the method was applied to determination of vanadium in edible salt samples, due to its applicability in high-NaCl-containing solutions. The validity of proposed method was proven by spike recovery experiments and also independent analysis by inductively coupled plasma mass spectrometry.     

岩溶表层带土壤温度和含水率对呼吸作用的影响

全球环境变化对岩溶区的碳循环产生重要的影响,而土壤呼吸作用在全球环境变化的影响和反馈的过程中具有十分重要的作用。因此,以岩溶区的岩溶表层带为研究对象,研究了土壤呼吸作用与土壤温度和大气降水量之间的响应机理和内在联系。研究结果表明：岩溶表层带的土壤呼吸作用具有单峰型的季节性变化特征。洼地0~5、10~20 cm 的土壤呼吸速率在范围变化分别为82.58 mg· m-2· h-1至412.89、151.39 mg· m-2· h-1至523 mg· m-2· h-1,最大值出现在8月中旬。坡地0~5、10~20 cm的土壤呼吸速率在范围变化55.05 mg· m-2· h-1至412.89、137.63 mg· m-2· h-1至495.47 mg· m-2· h-1,最大值出现也在8月中旬。洼地的土壤呼吸作用相对强于坡地,主要是由于坡地土壤相对洼地土壤较薄并且容易被降水冲刷搬运。在大气降水量不成为限制土壤呼吸作用的因子下,土壤温度为主要控制土壤呼吸作用的因子。因此,该研究可为控制土壤呼吸作用缓和大气CO2的升高和温室效应应对策略,为国家固碳减排的科学决策提供理论依据。     

盐沼植物群落研究进展：分布、演替及影响因子

盐沼是全球温带及亚热带地区的主要滨海湿地类型之一,在我国分布广泛。盐沼湿地生态系统敏感、脆弱且具有重要的生态系统服务功能。理解盐沼植物群落时空分布动态的一般规律与生态学机制,是开展盐沼生态系统研究的基础与关键。海陆交界的特殊环境特征是影响盐沼湿地植物群落的空间分布及演替过程的主要因素。在海洋潮汐作用下,盐沼湿地中的盐度、水淹强度、氧化还原电位等非生物因子往往呈梯度分布,这也导致了生物群落中种内、种间关系的变化。在非生物及生物因子的共同作用下,盐沼植物群落也往往沿高程梯度呈带状分布。环境变化是盐沼植物群落演替的驱动因素,在海岸线相对较为稳定的盐沼,植物群落的演替多属自发演替,而在靠近的大型河口的一些持续淤涨的盐沼,植物群落演替通常属于异发演替。沿海地区的水产业、流域上游及沿海地区的工程、污染及生物入侵等直接或间接的人类活动已对盐沼湿地植物群落的产生了深刻影响。经过数十年发展,国际上盐沼植物群落学研究的热点领域主要包括盐沼植物群落与其他生物群落的相互关系、植物群落在盐沼生态系统过程中的作用等。在全球变化背景下,盐沼植物群落对气候变化与海平面升高也日益成为盐沼植物群落学相关的热点。     

冻融作用下盐碱水田土壤含水率和氮素对有机碳影响研究

选择吉林西部前郭县盐碱水田土壤,进行实验室模拟冻融实验：以-5℃冻结1 d、5℃消融1 d作为1次冻融循环,揭示不同含水率和含氮量处理条件下土壤有机碳（SOC）的变化规律。结果表明,土壤含水率和含氮量是影响SOC含量的2个重要因素,冻融次数、土壤含水率、土壤含氮量以及冻融次数和土壤含水率、冻融次数和土壤含氮量的交互作用对盐碱水田SOC含量的影响显著（P〈0.05）。在1~3次冻融循环过程中,SOC含量明显降低,随着循环次数的增加,SOC含量降低速度减缓;适量的氮素和较低的含水率有利于SOC的稳定,初始含水率为50%的SOC含量明显低于含水率30%和40%的土壤,加入20%硝酸铵的SOC含量明显低于对照组和加入10%硝酸铵的土壤。研究结果对深入研究季节冻土区冻融期盐碱水田SOC变化规律,评估全年候SOC储量有重要意义。     

干旱胁迫对香蒲生长和叶绿素荧光参数的影响

采用野外调查方法,研究了不同土壤含水量条件下香蒲植株的形态、生物量、叶绿素含量和叶绿素荧光参数的变化。结果表明：（1）土壤含水量对香蒲株高影响显著,轻度、中度和重度干旱处理香蒲株高分别下降为对照（土壤水分始终饱和）的90.90%、68.19%和63.64%。（2）香蒲茎直径、叶长、叶宽和叶绿素含量均随土壤含水量的降低而呈递减趋势,枯叶率却明显增加。（3）不同土壤含水量条件下香蒲密度和生物量差异均达显著水平（P〈0.05）。轻度、中度和重度干旱组香蒲密度分别比对照下降41.67%、53.33%和66.67%;而对照香蒲单株生物量分别为轻度、中度和重度干旱组的2.25、5.54和7.45倍。（4）香蒲叶片最大光量子产量（Fv/Fm）和最大相对电子传递速率（Re,t,max）随土壤含水量的减少而明显降低。干旱降低了香蒲叶片光系统Ⅱ（PSⅡ）的光化学效率,抑制了香蒲的生长。     

通风方式对高含水率垃圾生物干化的影响

以高含水率混合收集生活垃圾为研究对象,研究了不同的通风方式(间隙通风10min/20min、间隙通风5min/25min、40℃热空气通风和间隙-连续通风)对生物干化影响.结果表明,40℃热空气通风和间隙-连续通风可提高产物含水率下降幅度、单位质量垃圾水分去除率、单位有机物降解脱水容量、产物低位热值;但堆体高温持续时间短,VS消耗量小,并且有机物稳定化程度低.经过18d的干化试验,4组试验产物含水率分别为39.6%,34.4%,23.7%,24.5%,相应的单位去除率(以原生垃圾质量计)为0.437,0.476,0.523,0.517kg/kg,低位热值为11954,12994,15760,14801kJ/kg,与原生垃圾相比,热值分别提高了121%、140%、191%及173%,以40℃空气通风产物热值最高.     

生活垃圾机械-生物预处理工艺优化

以宜昌市垃圾综合处理场为例,分析了通风量和水分对生物预处理的影响,进而优化生物预处理的实际应用工艺。实验结果表明:通风量与水分对预处理过程中堆体温度、pH、堆高变化影响明显,对挥发分变化影响不明显。选取每30 min风机送风8 min的通风方式,处理之前调整垃圾水分在40%～50%之间,可以取得较好的预处理效果。     

Study on tri-axial creep experiment and constitutive relation of different rock salt

To evaluate the effect of the long-term operation of a salt cavern in a given construction on rock deformation and its stability, tri-axial creep tests to the glauberite, anhydrite, and argillaceous rock salt are conducted, from which the creep curves as well as exponential functions of strain rate during the steady creep stage and creep constitutive equations of different rock salt in the experimental process derived are obtained. The study results show that: (i) Under the same deviatoric stress, the strain rate of argillaceous rock salt is lower than the glauberite and anhydrite, and the difference becomes larger with the increase of the deviatoric stress; (ii) The creep constitutive equations of different kinds of rock salt are in good agreement with the Burgers model, besides which the respective characteristics of these two creep models are compared. The change of creep parameters also illustrates the discrepancy of rock salt. The researching results can provide some references for long-term stability analysis of gas storage in salt caverns.