An improved method of fluorescein diacetate determination for assessing the effects of pollutants on microbial activity in urban river sediments

Journal of Soils and Sediments - The fluorescein diacetate (FDA) method has been widely used to quantify microbial activity rapidly and sensitively. However, due to high silt–clay ratios and...     

Composition of Typical Soil Minerals and Quantitative Analysis for Influence of Iron and Manganese Forms on Purple Soil Color in Northeastern Sichuan,China

Eurasian Soil Science - Eight soil samples from the Jurassic Shaximiao Formation (J2s) in the Sichuan Basin, China, were taken as the research object to explore the correlation and quantitative...     

某踏板车车架有限元分析

车架承受整车如发动机、传动装置等总成传给的各种力和力矩。为确保车架具有足够的刚度和强度,通过建立有限元模型,对车架进行模态分析,从而提前预测各种路况下车架受力情况,优化结构设计,减少车架问题发生。     

葡聚糖水合二激酶的生物学功能及其应用

葡聚糖水合二激酶(glucan-water dikinase,GWD)催化淀粉发生的磷酸化反应是植物临时淀粉降解的必要过程.该文总结了GWD的结构、生物学功能及其与其他淀粉代谢相关酶类的互作,以及GWD基因的研究进展及其在淀粉改性工艺上的应用现状,展望了GWD在淀粉磷酸化改性工艺上的应用前景,旨在为淀粉生物改性提供一种环境友好型、资源集约型的思路和方法.     

工科大学生创新人格特征探析及培养策略——基于人格特质理论的视角

基于创新人格特征在不同文化和专业领域的差异性,通过调研发现,工科大学生创新人格特征具有高聪慧性、高实验性、高自律性等11项特征,与其他专业领域创新人才人格特征既有共同性,也存在独特性。结合高校教育实际,通过巧用目标激励,开展探索式学习和参与式训练,加强制度意识教育和完善心理帮扶体系,开展工科大学生创新人格的培养和教育。     

果园害虫光电诱导杀虫灯及其远程移动负载机具

为了便于果园田间的中期耕作和转战严重爆发区域的虫害治理,研制了果园害虫光电诱导移动式捕杀机具,果园田间作业试验证实了4种机具的有效性和适应性。     

A portable soil nitrogen detector based on NIRS

As one of the most important soil nutrient components, soil total nitrogen (TN) content needs to be measured in precision agriculture. A portable soil TN detector based on the 89S52 microcontroller was developed, and a Back Propagation Neural Network (BP-NN) estimation model embedded in the detector was established using near-infrared reflectance spectroscopy with absorbance data at 1550, 1300, 1200, 1100, 1050, and 940 nm wavelengths. The detector consisted of two parts, an optical unit and a control unit. The optical unit included six near-infrared lamp-houses, a shared lamp-house drive circuit, a shared incidence and reflectance Y-type optical fiber, a probe, and a photoelectric sensor. The control unit included an amplifier circuit, a filter circuit, an analog-to-digital converter circuit, an LCD display, and a U-disk storage component. All six absorbance data as inputs were used to calculate soil TN content by means of the estimation model. Finally, the calculated soil TN content was displayed on the LCD display and at the same time stored in the U-disk. A calibration experiment was conducted. The soil TN content correlation coefficient (R ²) of the BP-NN estimation model was 0.88, and the validation R ² was 0.75. This result indicated that the developed detector had a stable performance and a high precision.     

南方山地森林小班蓄积量调查方法的对比分析

以南方山地森林为研究对象,选取有代表性的4个小班,分别采用角规抽样调查法、中心样圆法、样圆群法、六株木法、垂直样带法、标准地法共6种方法对小班蓄积量进行测定,并从6种方法的调查精度、误差大小、工作量及工具和仪器的难易程度等方面对小班蓄积量进行了对比分析,认为角规抽样调查法是最适合南方山地森林小班蓄积量的调查方法。     

重茬肥对重茬烤烟各器官磷吸收的影响

以重茬4年烤烟为试验材料,设置对照、常规施肥、重茬肥3个处理,研究了烤烟磷吸收规律。结果表明:烤烟收获期重茬肥处理根系内磷吸收量分别高于对照和常规施肥处理51.32%、38.12%;茎内磷吸收量重茬肥处理分别高于其他2个处理31.54%、17.58%;下部叶、上部叶重茬肥处理磷吸收量分别高于对照40.49%、74.76%;中部叶重茬肥处理分别高于对照和常规施肥处理31.14%、7.09%。综合分析认为,重茬肥对可显著提高烤烟各器官磷吸收量。     

Physiological and related anthocyanin biosynthesis genes responses induced by cadmium stress in a new colored-leaf plant “Quanhong Poplar”

The worsening of Cadmium (Cd) pollution has intensified the urban ecological environment deterioration in the world. Purifying contaminated environment using the tall, colored-leaf woody plants has been proved as an aesthetically pleasing approach. However, the effects of Cd stress on colored-leaf woody plants have been little reported. Present hydroponic experiments were carried out to study the physiological and related anthocyanin biosynthesis genes responses to Cd stress in “Quanhong Poplar” plants. The experiments consisted of four Cd levels (0, 50, 100 and 150 μM). Leaves were sampled at 5, 10, 20, 30, 40, 50, and 60 days after the first treatment for detection of related enzyme activities and genes expression. The results showed that the plants treated with 100 or 150 μM Cd presented obvious toxicity symptom, i.e. the inhibition of growth and the decrease of chlorophyll and anthocyanin contents. However, plants growth was enhanced and the synthesis of chlorophyll, anthocyanin were promoted when the plants were subject to 50 μM Cd stress. Furthermore, the activities of relative enzymes as well as their genes expression were induced, which indicated that low concentration of Cd induced the anthocyanin accumulation in “Quanhong Poplar” plants, which suggested that using “Quanhong Poplar” to purify contaminated environment would be an aesthetically pleasing approach, which would not only remediate contaminated environments but also bring landscape effects.