Cross‐linked polyacrylates in post‐mining substrates: persistence and effects on plant growth

Application of hydrophilic polymers composed of cross‐linked polyacrylate can improve soil water‐holding capacity and accelerate the restoration of post‐mining substrates. In this work, we studied the persistence of a polyacrylate polymer incorporated into a soil and its impact on plant nutrients at a reclamation site of former lignite mining in Lusatia (Germany). In contrast to autumn application, the incorporation of the polymer enhanced the sequestration of plant‐derived carbon in the soil, which was reflected by a significant increase in the concentration of a lignin marker. Attenuated total reflexion–Fourier transform infrared spectra (ATR‐FTIR) and total elemental contents in the applied polymer suggested an intensive cation exchange between the polymer framework and the soil‐forming substrate. In addition, there was an enrichment of carbonaceous material, which seems to reduce the swelling and thus the water‐holding capacity of the cross‐linked polyacrylate. Conversely, this process protected the polymer structure from rapid decomposition.     

Effect of aging at different temperatures on LAOS properties and secondary protein structure of hard wheat flour dough

The effects of aging from t = 0–108 h at two different temperatures (4 and 25 °C) on the non-linear viscoelastic rheological properties and secondary protein structure of hard wheat flour dough (HWD) were investigated using large amplitude oscillatory shear tests (LAOS) coupled with Fourier transform infrared spectroscopy (FTIR) and SDS-PAGE. Storage (G') and loss (G'') moduli rapidly decreased during aging at 25 °C. Subjecting HWD to progressively longer aging times at 25 °C caused dramatic changes in the non-linear viscoelastic properties demonstrated by strain softening (negative values of e₃/e₁) and shear thinning (negative values of v₃/v₁) behavior. Elastic Lissajous curves of the unaged control dough showed clockwise turn and wider elliptical trajectories as dough aging proceeds especially at higher temperatures. Other non-linear LAOS parameters (G'_M-G''_L, η'_M-η'_L, S and T) supported that aging process at higher temperature caused a progressive change in dough structure from strain stiffening to strain softening behavior while dough samples aged at 4 °C showed fairly close behavior with the control dough sample. FTIR spectra indicated that the relative content of β-sheet and β-turn structures decreased while the content of α-helix structure increased for all dough samples as a result of dough aging. SDS-PAGE results supported the breakdown of high molecular weight (HMW) and low molecular weight (LMW) glutenin subfractions. Aging at the higher temperature of 25 °C decreased the HMW/LMW ratio from 0.77 to 0.59, while the ratio was 0.73 for the dough aged at 4 °C which is fairly close to the control sample. Our results show that the degradation rate of gluten/starch network was triggered by aging at higher temperature, longer aging time, and natural fermentation which resulted in increasing acidity and increase in endogenous proteolytic and amylolytic activity, and also increasing gluten solubility and break down of intermolecular disulfide bonds at acid pH.     

吉林省部分地区鸡源大肠杆菌耐药性监测

以吉林省部分地区临床分离的43株鸡源大肠杆菌为研究对象,采用常规的药敏试验方法,对其耐药性进行监测。结果表明:吉林省部分地区鸡源大肠杆菌普遍耐药,耐药菌株大多数为多重联合耐药。本研究所采用的15种抗生素中,抑菌作用最强的是兽医临床上尚未使用的头孢唑啉和丁胺卡那霉素,其次为头孢哌酮和卡那霉素;大肠杆菌对四环素、氨苄青霉素、青霉素等药物表现出100%的耐药性。     

食用油反式脂肪酸傅里叶红外光谱重组检测技术

以食用油、反式脂肪酸标样及矿物精油为试验材料,采用傅里叶红外光谱重组(SR-FTIR)技术检测食用油中反式脂肪酸含量,并与标准红外分析方法(SB-ATR-FTIR法)进行比较.结果表明:SR-FTIR模型反式脂肪酸含量预测值与实际加入量高度线性相关,斜率为1.02,标准差小于0.05;SR-FTIR模型的灵敏度要比标准方法模型高20余倍.     

甜高粱茎秆残渣热裂解过程及其生物油成分分析

阐述了流化床反应器热裂解过程,以甜高粱茎秆残渣为生物质原料,在流化床反应器上进行了快速热裂解试验,并利用傅立叶变换红外光谱分析技术对产生的生物油化学成分进行了分析.结果表明:在500℃条件下的生物油产油率较高,为57%;生物油含有多种官能团和有机成分,主要有醇、酚、醚、酯及芳香烃类,是一种十分复杂的有机化合物的混合物.     

DME发动机非常规排放物的检测与分析

用气相色谱仪和傅立叶红外光谱仪对燃用DME的ZS195柴油机的排气中的甲醛(HCHO)、甲酸甲酯(CHCOOCH3)、甲酸(HCOOH)非常规排放物进行了检测和分析。结果表明,DME发动机的尾气排放中,均检测到HCHO,HCOOCH3,HCOOH排放物,且甲醛是非常规排放物中的主要成分,甲醛、甲酸甲酯的排放量随转速上升而略有上升,随负荷增加而不同程度的减少,而甲酸排放量变化则不甚明显。     

盛夏西太平洋副热带高压对陕西降水的影响

利用1961-2008年陕西78个气象站7-8月降水资料、西太平洋副高逐月指数资料及500hPa位势高度场和700hPa风场月平均再分析资料,通过相关、回归分析、小波凝聚谱分析等方法探讨盛夏西太平洋副热带高压对陕西降水的影响及机制,为盛夏陕西降水的气候预测提供依据.结果表明,盛夏副高强度、脊线、西伸脊点指数与陕西降水关系密切,副高偏强偏西时陕西降水偏多,副高偏北时陕西北部降水偏多、南部偏少.8月副高3个指数与陕西降水的相关关系更为密切,通过显著性检验的站点明显增多.副高的强度和位置变化引起副热带和中高纬度大气环流的异常,进而影响陕西降水.8月副高偏强偏西时,巴尔喀什湖阻高增强,700hPa西南季风的水汽输送增强,陕西位于冷暖空气交汇区,降水偏多;副高偏南时,水汽辐合区位于陕南,陕西南部多雨、北部少雨;副高偏北时,水汽辐合区位于陕北,陕西北部多雨、南部少雨.8月副高强度指数与同月陕西降水的显著共振周期为7 ～8a,且副高强度变化超前于陕西降水变化1.26a,说明8月副高强度的年际变化是引起同月陕西降水年际变化的重要原因.     

不同母质发育土壤的中红外吸收光谱特征

选取湘东丘陵区四种典型母质发育土壤(酸性紫色土、花岗岩红壤、板岩红壤和第四纪红土红壤),采集剖面(深至母岩/母质层)样品,应用傅里叶变换红外光谱仪研究灼烧去除有机质处理、土层深度和母质类型对土壤中红外吸收光谱特征的影响,分析吸收光谱与土壤理化性质的关系。结果表明,去除有机质后,特征区的中红外吸收值升高,反映矿物质对红外吸收谱线的强烈影响。在剖面上,底土(60~80 cm或100~120 cm)的中红外吸收值高于表土(0~20 cm),与土壤有机质含量的剖面分布相反。四种土壤的中红外光谱均属典型的高岭石图谱。砂粒、粘粒含量与红外吸收值的相关性最好,砂粒含量的最大相关系数(0.51)出现在3700、913和720~540 cm~(-1)附近,粘粒含量的最大相关系数(0.54)出现在1100~694 cm~(-1);本研究表明,原土的中红外吸收光谱特征主要受矿物质的支配,可以很好地反映土壤质地的状况,指示土壤质量变化。     

硼酸共沉淀法合成含硼氧化铁的结构状况解析

在水合法制备针铁矿过程中添加HBO3,对合成的样品作红外光谱和比表面积分析.结果表明,共沉淀法合成的样品在1343 cm处有特征吸收峰,说明在针铁矿形成过程中,如果有H3BO3参与,则形成的氧化铁中存在Fe-O-B键结构,可能在氧化铁内部有一种新硼铁化合物生成.比表面积测定表明,含B氧化铁比表面积增加4倍以上,反映了氧化铁与H3BO3并非机械混合物,其表面性质因为Fe与B反应而发生改变,B阻止氧化铁向高聚合态转变.     

苹果霉心病可见/近红外透射能量光谱识别方法

针对苹果霉心病从外表无法识别的难题,提出基于可见/近红外透射能量光谱进行快速无损识别的模型和方法。在200~1 100 nm波段内采集了200个苹果的透射能量光谱数据,随机选取140个样品作为训练集,剩余60个样品作为测试集。用平滑法和多元散射校正对光谱数据进行预处理。基于全光谱、连续投影算法(SPA)提取的12个特征波长、主成分分析(PCA)提取的9个主成分,分别建立了偏最小二乘判别法、误差反向传播人工神经网络和支持向量机(SVM)识别模型。实验结果说明,应用PCA-SVM建立的模型识别性能最优,该模型对测试集和训练集中霉心病果和健康果的识别正确率分别为99.3%和96.7%。基于SPA和PCA所建模型的输入变量数仅相当于基于全光谱所建模型输入变量数的0.99%和0.74%,极大降低了模型的复杂度。研究结果表明,该方法是可行的且具有较高识别准确度,为苹果在线内部品质分级和便携式苹果霉心病检测仪的研究提供了技术依据。