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71.
Surface runoff may be generated when the rainfall intensity exceeds the infiltration capacity, or when the soil profile is saturated with water. Indications exist that both types of overland flow may occur in hilly agricultural loess regions. Here, for a loessial hillslope under maize in the southern part of The Netherlands, it was shown, with pressure head and runoff measurements, that Hortonian overland flow occurs during typical summer rain events. Surface runoff was initiated after saturation of the top 5–10 cm of the soil. Deeper in the soil, unsaturated conditions prevailed while runoff took place. Peak runoff discharges at the outlet of the subcatchment occurred a few minutes after peak rainfall intensities were measured. It appeared that SWMS_2D, a two-dimensional water flow model, was capable in simulating observed pressure head changes and runoff. Simulated potential runoff for the transect studied was higher by a magnitude of three than the measured areal average. This indicates effects of surface ponding, and the probable location of this particular transect in a region with high runoff production.  相似文献   
72.
The absorption reactions of arsenite on Fe (hydro-)oxides are studied. The three absorbent types are Fe(OH)3 gel and two Fe (hydro-)oxides, in which the Fe(OH)3 gel was dried in a microwave oven under vacuum at 80℃. It is found that pH changes from 9.71 to 10.36 in 6 minutes after the Fe (OH)3 gel was mixed with NaAsO2 solution, as the arsenite replaces the OH- in goethite and Fe(OH)3. At the 40th minute after the start of the reaction, pH decreases, which is most probably because that the monodentate surface complex of absorbed arsenite has changed into mononuclear-bidentate complex and released proton. The decline in pH values indicates not the end of the absorption but a change in the reaction type. Temperature and dissolved gas has little effect on these two types of reactions. The total absorption of arsenite increases after the absorbent is irradiated with ultrasound, which also lead to difficulty in separating the solids from solution. The absorption capacity for arsenite of Fe(OH)3 gel dried in a microwave oven under vacuum is 53.18% and 17.22% respectively better than that of Fe (OH)3 gel and gel dried at 80℃. The possible reasons are that the water molecules in the gel vibrates with high frequency under the effect of microwave irradiation, thereby producing higher porosity and improved surface activity.  相似文献   
73.
为了研究起伏海面对雷电电磁传播的影响,本文利用Barrick表面阻抗理论和Wait近似算法,采用改进二维分形海面模型模拟起伏海面,利用数值模式,分析起伏海面的雷电电磁传播特征,并进一步讨论了起伏海面对时差法闪电定位系统定位精度的影响。结果表明:起伏海面对垂直电场和磁场的峰值的影响不显著,但会引起波形的上升期时间的延长,浪高越大,影响越明显;随着观测距离的增加,雷电垂直电场波形的上升时间逐渐变长;风速的变化与雷电垂直电场波形的上升时间成正比;由于海面起伏引起雷电电磁场波形在传播中的变化会影响基于时差法闪电定位系统的定位精度,定位误差可达几至十几公里。  相似文献   
74.
以大弹涂鱼为研究对象,应用单细胞凝胶电泳技术并结合外周血基因组DNA琼脂糖凝胶电泳,研究了镉胁迫对大弹涂鱼外周血细胞的遗传损伤。结果表明:(1)镉对大弹涂鱼外周血细胞是遗传毒性而非细胞毒性,并且产生的遗传损伤存在显著(P0.01或P0.05)的剂量效应,染毒1h的大弹涂鱼的全长和尾长与浓度的相关方程分别是y=29.592x-10.576(r2=0.9786),y=28.417x-14.859(r2=0.9857),染毒2h的大弹涂鱼的全长和尾长与浓度的相关方程分别是y=32.044x-5.0235(r2=0.941),y=29.911x-9.539(r2=0.9635)。(2)DNA的损伤程度和污染胁迫之间存在着时间效应。以上结果表明,DNA损伤可作为大弹涂鱼受镉胁迫时的生物指标。  相似文献   
75.
黄海西北近岸沉积物中细菌群落空间分布特征   总被引:3,自引:0,他引:3  
采用16S rDNA文库和变性梯度凝胶电泳(DGGE)技术,对黄海西北部3个近岸站位沉积物中细菌群落多样性及空间分布特征进行了调查和解析。对表层沉积物16S rDNA序列统计表明,各站位细菌群落多样性很高,γ-和δ-变形菌纲分别占克隆序列总数的20%~32%,是沉积物中的绝对优势类群。DGGE图谱分析表明,同一站位中不同深度的细菌群落结构相似性较高,而不同站位间群落结构相差较远。研究表明在黄海西北近岸沉积物中细菌群落多样性较高,优势类群明显,在较小尺度范围内群落结构的垂直变化不明显。  相似文献   
76.
一种水产动物病毒现场检测免疫芯片的制备与应用   总被引:4,自引:2,他引:2  
采用原子力显微镜对氨基化玻片及6种不同方法修饰玻片进行表面特征分析,并比较了硝酸纤维素(NC)膜、PVDF膜以及以上不同修饰玻片对抗体的固定效率、固定效果,最终选择琼脂糖修饰玻片作为芯片载体。将纯化后的兔抗血清(捕获抗体)点样至琼脂糖修饰玻片上,制备免疫芯片,与待检样品(病毒感染的靶器官组织)匀浆液孵育形成复合物,该复合物被辣根过氧化物酶(HRP)标记的特异性单克隆抗体(单抗)识别,经底物显色,得到肉眼可见的检测结果。通过改变芯片制备及应用过程中的具体条件参数,对各条件进行了优化,并采用生物素-链亲和素(BAS)标记特异性单抗作为检测抗体以提高检测灵敏度。基于此夹心免疫分析原理制备的WSSV、LCDV现场检测免疫芯片,病毒的最低检出量分别为82.50ng/ml、0.88μg/ml,在一定的抗原浓度范围内,病毒浓度的对数值与信号强度呈线性关系;采用BAS放大检测信号后,病毒的最低检出量为12.38ng/ml、0.22μg/ml。该免疫芯片与酶联免疫吸附法(ELISA)及免疫荧光法(IFAT)对同种样品的检测结果高度一致。  相似文献   
77.
Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was applied in the detection of the end point temperature (EPT) of thermal denatured protein in fish and meat in this study. It was also used in studying the thermal denatured temperature range of proteins in salmon and chicken meat. The results show that the temperature ranges of denatured proteins were from 65 ℃ to 75 ℃ , and these temperature ranges were influenced by the processing methods. Through SDS-PAGE, the features of repeated he...  相似文献   
78.
Dissolved proteins in seawater samples collected from a coastal area of Tokyo Bay, Sagami Bay and a location off the Kuroshio Current were investigated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE). Four to nine protein bands were detected in SDS-PAGE in the apparent molecular weight (MW) range from 12 kilo Dalton (kDa) to 49 kDa. The 2-DE technique distinguished 10 to 46 protein spots exhibiting isoelectric point (pI)/MW ranging 4.3–9.2/12–63 kDa. The elecrophoretic patterns were similar between the coastal and pelagic samples, as well as previously reported patterns from various pelagic areas. The close similarity of electrophoretic mobility on both SDS-PAGE and 2-DE gels indicates the compositional homogeneity of dissolved proteins in seawater throughout a broad range of marine environments. Proteinaceous dissolved organic matter (DOM) that was unresolved and smeared staining characteristics on both SDS-PAGE and 2-DE gels was first observed in Tokyo Bay waters in the present study and its possible sources are discussed. Although the two protein species, 48 kDa and 39 kDa proteins, have been identified as homologues of Porin P and low molecular weight-alkaline phosphatase of Pseudomonas aeruginosa PAO1, respectively, four strains of P. aeruginosa and two species of Pseudomonas spp. have been newly identified as the source organisms of these proteins using the N-terminal amino acid sequence data determined in previous studies.  相似文献   
79.
西施舌外套膜蛋白质组双向电泳体系的构建   总被引:3,自引:1,他引:2  
田美  申欣  程汉良  孟学平 《海洋科学》2009,33(11):32-36
建立了西施舌(Coelomactra antiquata)外套膜蛋白质组的双向凝胶电泳体系,比较分析了不同pH梯度胶条、水化条件的优化及不同染色方法对双向电泳结果的影响.结果表明:用pH 4~7的非线性胶条,水化时加上除盐步骤,采用硝酸银染色,即可获得高分辨率、高重现性的双向电泳图谱,为进一步研究西施舌外套膜蛋白质的组成奠定了基础.  相似文献   
80.
米氏凯伦藻(Karenia mikimotoi)近年在我国福建、浙江和广东沿海经常形成赤潮,其赤潮不仅影响到海洋生态系统的稳定,也严重威胁到水产养殖以及人类生命健康安全。本论文以米氏凯伦藻为研究对象,建立了米氏凯伦藻细胞表面膜蛋白质荧光标记技术和细胞膜蛋白质提取方法,运用荧光差异凝胶电泳技术(2-DDIGE)对膜蛋白质进行了分析,并研究了米氏凯伦藻的膜蛋白质组及其对环境温度变动的响应。实验共鉴定到44个细胞表面膜蛋白,其中有效注释27个,主要为转运蛋白、HSP70蛋白家族和捕光蛋白等。米氏凯伦藻在20°C条件下的细胞生长和光合作用要明显好于16°C和12°C,但16°C和12°C条件下的差别不大,表明低温限制了米氏凯伦藻的生长。当米氏凯伦藻从12°C快速转移至16°C和20°C时,藻细胞密度和光合作用效率短时间迅速降低,但细胞很快即适应温度变化。细胞膜上的转运蛋白和光合作用蛋白在其适应温度变化中起着重要作用。  相似文献   
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