The influence of the high and low molecular weight fractions of a bleach kraft mill effluent on the microbial activity of activated sludge

The high molecular weight (HMW) fraction (> 1000 Da) of bleached kraft mill effluent (BKME) is the principal source of adsorbable organic halide (AOX), colour and chemical oxygen demand in treated effluent. The influence of HMW material on the microbial activity of activated sludge microorganisms was studied in a series of batch growth experiments using fractionated effluent. The HMW material in the untreated effluent comprised 80% of the AOX but only 20% of the soluble COD. Multivalent metal ions had a greater affinity for this HMW fraction. The addition of HMW material to the LMW fraction had a stimulatory effect on microbial activity as measured by increases in biomass and substrate utilization. Chemical characterization and subsequent growth experiments revealed that nitrogen, which was deficient in the LMW effluent, was primarily associated with the HMW material. The association of nitrogen with the HMW fraction may have an important role on the behaviour of nitrogen within a biological treatment system and in the receiving environment.     

基于SAM与SVM的高光谱遥感蚀变信息提取

高光谱遥感技术的发展,提高了遥感技术的定量化水平,要求人们从光谱维去理解地物在空间维的变换。提出了一种光谱角匹配技术（Spectral Angle Mapper,SAM）与支持向量机（Support Vector Machine,SVM）相结合的高光谱遥感蚀变信息提取模型,在光谱维提取地表的蚀变信息。鉴于SAM算法仅考虑波谱矢量方向,忽略辐射亮度大小的缺点,利用SVM算法对SAM的提取结果进行二次分类,利用网格搜索法并结合分类精度评估进行参数寻优。通过AVIRIS高光谱数据实验证明,提取的蚀变信息分类精度为78.172 6%,Kappa系数为0.712 5。该模型计算方便,对于解决光谱维的地物分类及相似矿物的蚀变信息提取具有一定的实际意义。     

塔里木河下游土壤水分和地下水位变化对植被的影响

Based on data collected over five years of monitoring the Lower Tarim River, we analyzed the variability of soil moisture content (SMC) and the relationship between SMC,groundwater table depth (GWD) and vegetation by using the methods of coefficient of variation (Cv), Pearson correlation and regression. The results of the variability of SMC indicate that it rose with increase in depth of soil layer - SMC in the soil layer of 0-60 cm was relatively small compared to SMC in the soil layer of 100-260 cm which showed a significant increase in variability. SMC and GWD before and after ecological water diversions exhibited significant differences at the site of the Yingsu transect and its vicinity of the watercourse,especially SMC in the soil layer of 100-260 cm increased significantly with a significant rise of GWD and reached maximum values at a GWD of about 4 m. Plant coverage and species diversity significantly improved with increases in SMC in the soil layer of 100-260 cm, both of them approached the maximum values and 92.3% of major plant species were able to grow when SMC was ＞ 10%. To restore the ecosystem of desert riparian forest along the Lower Tarim River, the GWD must be maintained at ＜ 4 m in the vicinity of the watercourse and at about 4 m for the rest of this arid region.     

高山冰川作用下流域水库汛期分期

针对高山冰川作用下流域水库汛期分期的实际问题,以玛纳斯河流域夹河子水库为研究对象,识别汛期划分的主要影响因素,选择汛期划分依据,采用定性和定量分析相结合的方式,综合成因数理统计、矢量统计、模糊分析、系统聚类4种汛期分期方法,分析各种方法适用性,提取合理成分,结合天山北坡气候带的水文气象特征和水库控制运用特点,确定汛期范围：7月10日至7月30日为前汛期, 8月1日至8月15日为后汛期。为夹河子水库的分期运行提供了理论依据。     

Application of simplified rapid equilibrium models in simulating experimental breakthrough curves from fixed bed biosorption reactors

A modelling approach for a fixed bed biosorption column is presented. The Advection–Dispersion–Reaction (ADR) equation has been applied as the basic modelling equation for the special case of Local Equilibrium (LE). The model implements the minimum parameters for describing a fixed bed biosorption column, employing the geometrical dimensions of the bed, the packing arrangement, the operating conditions of the system, and the sorptive characteristics of the biosorbent material. An apparent axial dispersion coefficient has been used as a key parameter of the model. The authors compare model predictions to selected examples of experimental biosorption breakthrough curves reported from pilot scale work. Although the main assumption of the model is that biosorption equilibrium is rapid, the use of an apparent overall dispersion coefficient makes the model applicable for the cases where mass transfer resistances are present in the liquid and solid phases.     

A numerical study of natural convection heat transfer in a vertically eccentric spherical annulus

The results of a numerical investigation of the natural convection process between isothermal vertically eccentric spheres with hotter inner core, are being presented. The Grashof and the Prandtl numbers have been kept constant at 4×10⁴ and 10 respectively. Eccentricities varying from −0.75 to +0.75 have been studied. From the numerical solution, it is possible to explain the average results obtained previously for the regime where the steady crescent flow pattern exists. Negative eccentricities have been found to enhance convection while positive eccentricities have the reverse effect. Results also show that heat transfer actually increases slightly for very high positive eccentricities where conduction plays an important role.     

药桑多糖对四氯化碳所致大鼠肝损伤的保护作用

目的：研究药桑多糖对四氯化碳（CCl4）所致大鼠肝损伤的保护作用。方法：取健康Sprague-Dawley（SD）大鼠40 只,根据体质量随机分为5 组：对照组、CCl4损伤组、药桑多糖低（50 mg/（kg•d））、中（100 mg/（kg•d））、高（200 mg/（kg•d））剂量组,每组8 只,连续灌胃7 d后,除对照组外,其余各组大鼠腹腔注射CCl4橄榄油溶液制造肝损伤模型。24 h后,取血清测定谷丙转氨酶（alanine aminotransferase,ALT）、谷草转氨酶（aspartate aminotransferase,AST）活力以及胆红素含量,取各器官计算脏器指数并测定肝脏超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶（catalase,CAT）、谷胱甘肽过氧化物酶（glutathionperoxidase,GSH-Px）活力,以及丙二醛（malondialdehyde,MDA）、干扰素-γ（interferon-γ,IFN-γ）、肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）、白细胞介素-10（interleukin-10,IL-10）含量,并对肝脏进行组织切片观察。结果：100、200 mg/（kg•d）剂量的药桑多糖能显著增加大鼠体质量（P＜0.05）,降低肝脏指数（P＜0.05）、肾脏指数（P＜0.05）和脾脏指数（P＜0.01）,能显著抑制CCl4所致肝损伤大鼠血清ALT、AST活力和胆红素含量的升高（P＜0.05）;肝脏MDA、IFN-γ、TNF-α含量显著降低（P＜0.05）,SOD、CAT、GSH-Px活力以及IL-10含量显著升高（P＜0.05）。50 mg/（kg•d）剂量的药桑多糖能显著降低肝损伤大鼠的肝脏指数、肾脏指数和脾脏指数（P＜0.05）,显著增加肝脏GSH-Px活力和IL-10含量（P＜0.05）,降低肝脏TNF-α含量（P＜0.05）。结论：药桑多糖对CCl4诱导的大鼠肝损伤具有明显的保护作用,其肝脏保护作用与提高肝脏抗氧化能力及抑制肝脏炎症有关。     

Spatio-temporal remote sensing of vertical and seasonal chlorophyll-a:b ratio in Tamarix ramosissima

Remotely sensed spectral reflectance data have provided avenues for large-scale non-destructive estimation of temporal and spatial variations of physiological processes in plants. This study established the potential for tracking (chlorophyll) chl-a:b ratio in Tamarix ramosissima based on -leaf-scale photochemical reflectance index (PRI) at Fukang Station of Desert Ecology in the hinterland of the Junggar Basin, Xinjiang, northwest China. Leaves were sampled on a monthly basis over a 3-year growing period. T. ramosissima tolerance to the fragile arid conditions revealed higher coefficient of determination (R² > 0.6) between chl-a:b ratio and N content at each light condition. This implied a higher potential for irradiance acclimation through plasticity in photosynthetic apparatus, and hence an important attribute for colonizing wider desert ecological range. PRI was negatively correlated to chl-a:b ratio regardless of season but was more sensitive to changes in light condition. The modified PRI (PRI_mod, R₅₁₀–R₅₇₀ nm) performed better than the original PRI (PRI, R₅₃₁–R₅₇₀ nm) with R² improvement in all data sets of this species. These results implied that seasonality and leaf age, within canopy resource variation and the individual species must be considered when applying PRI_mod to estimate chl-a:b ratio. Application of empirical indices avails a non-destructive timely leaf-level, species and site-specific avenue of detecting vegetation status in arid ecosystems. Remote estimation of chl-a:b ratio obtained at leaf scale in this study could be scaled to ecosystem and global scale by effective estimation of spatial distribution and seasonal variation using other pigment-related vegetation index such as the normalized difference vegetation index, or combination of PRI and the water band index.     

干旱区植物叶片识别研究

现有植物叶片识别方法都是基于扁平状叶片，而干旱区植物叶片多呈针叶，因此不适合干旱区植物叶片的识别，使得对于干旱区植物研究主要依靠专家识别，不利于对干旱区植物叶片的进一步研究。提出使用差异性值监督局部线性嵌入算法D-LLE，充分挖掘样本之间的类别信息，提高干旱区植物叶片的识别效率。首先利用金字塔梯度方向直方图（PHOG）的方法提取叶片图像特征，再使用PCA、LLE、WLLE、D-LLE等主流的降维算法，对提取的PHOG特征进行降维，最后建立支持向量机（SVM）的分类模型对植物叶片图像分类。经过这四种降维算法后的平均识别率分别为76.3%、85.3%、89.1%、95.5% ；骆驼刺、苦豆子和沙枣的叶片正确识别率，相对其他植物叶片较低。通过实验证明了PHOG特征在植物叶片特征提取的可行性，使用D-LLE算法相比传统特征降维的算法具有更高的效率，且较适合于干旱区植物叶片的自动识别分类。     

蛋白酶基因的克隆与表达研究进展

蛋白酶在各领域的应用愈加广泛,但其大规模工业生产受到诸多因素制约。利用基因工程技术对蛋白酶基因进行改良和克隆表达,开发高产量、高纯度、高活力的蛋白酶资源成为研究的热点。本文对蛋白酶的分类、结构与功能、菌种选育等进行了概述,同时分析了蛋白酶基因在原核和真核生物中的克隆与表达研究进展,并对未来蛋白酶基因工程的发展趋势进行了展望。