Do cover crops change the lability of phosphorus in a clayey subtropical soil under different phosphate fertilizers?

Plants have developed different mechanisms to absorb and solubilize phosphorus (P) in the soil, especially in environments with low P availability. This study evaluated the effects of different winter cover crops on soil P availability in a clayey subtropical (Hapludox) soil receiving soluble P fertilizer and a rock phosphate applied to the summer crop, under no‐tillage. The experiment was carried out over 3 yrs (2009–2011) with five different cover crop species: common vetch, fodder radish, ryegrass, black oat, white clover and fallow as control. The soil was sampled after the third year of cover crop cultivation and analysed for inorganic and organic P forms according to the well‐established Hedley fractionation procedure. Phosphate fertilizers promoted accumulation of both labile and nonlabile P pools in soil in the near surface layer, especially under rock phosphate. Fertilizer applications were not able to change P fractions in deeper layers, emphasizing that the Brazilian clayey soils are a sink of P from fertilizer and its mobility is almost nil. Although the cover crops recycled a great amount of P in tissue, in a short‐term evaluation (3 yrs) they only changed the content of moderately labile P in soil, indicating that long‐term studies are needed for more conclusive results.     

Association of TNF-α, IL-10 and IL-6 promoter polymorphisms in pulmonary tuberculosis patients and their household contacts of younger age group

Single nucleotide polymorphisms (SNPs) of cytokine genes have been found to be involved in the clinical outcome of Tuberculosis. The present study was aimed to identify the high risk genotypes in Tuberculosis patients and their household contacts. A total of 490 subjects were studied which includes 150 active pulmonary tuberculosis patients (APTB), 190 household contacts (HHC) and 150 healthy controls (HC). The SNPs of TNF-α (-308A/G), IL-10(-1082G/A) and IL-6(-174G/C) were performed by ARMs PCR. The IL-10 GA genotype showed significant association in APTB and HHC and was 2.3 times higher risk in APTB and 3.7 times in HHC compared to HCs. The A allele was found to be significantly associated with the risk of disease. The CC genotype of IL-6 was found to be significantly associated in APTB and an insignificant positive association in HHCs. The multifactor dimensionality reduction (MDR) analysis indicated that the genotypes of IL-6 were showing high risk with GA genotype of IL-10. In conclusion the gene interaction may be useful for identification of genotypes as biomarkers to distinguish high risk individuals.     

切屑卷曲的力学分析及其应用

在试验和理论分析的基础上，本文提出了复合卷曲的切屑比向上卷曲的切屑、当侧卷程度较大时比例向卷曲的切屑易于折断的观点，并且讨论了切屑产生复合卷曲及侧向卷曲的条件，这些对断屑槽的设计和使用有重要意义。     

牛Myostatin基因单核苷酸多态性分析

Myostatin基因即肌肉生长抑制素,是一种肌肉生长的负调控因子。应运PCR-SSCP和测序的方法对中国秦川牛、南阳牛以及国外引入品种皮埃蒙特牛双肌基因的第三外显子进行了多态性分析。结果表明:第三外显子938处G→A的单核苷酸的突变造成了南阳牛、皮埃蒙特牛第三外显子扩增片段多态性,秦川牛则不然。     

作物活体多探头测量仪的研制

采用TP—801单板机制作作物活体多探头测量仪。该机可在田间对生长状态下的农作物进行多点体内养分积累、运输、分配等测定,且结果可靠。     

2种胃膜素制备方法的比较

[目的]比较分析制备胃膜素的2种方法，优化制备方法，为工业化规模生产提供试验依据。[方法]以猪胃黏膜为材料，采用单产工艺和联产工艺提取胃膜素，比较分析2种制备方法所得胃膜素的性状、得率、总氮含量和还原性物质含量的差异。[结果]2种方法提取的胃膜素在黏度、酸度、干燥失重和炽灼残渣等方面差异不大，总氮含量和还原性物质含量也无明显差异，均符合国家标准。单产工艺胃膜素得率较高，平均达3．5％，联产工艺得率偏低，仅有1．7％，但联产工艺可以得到副产品胃蛋白酶。[结论]单产工艺的得率高于联产工艺，联产工艺可以同时得到副产品。     

某厂区办公楼的结构设计

笔者结合工程实例,采用SATWE软件对单跨框架结构进行计算分析,并浅析了设计中应重点注意的问题。     

基于Atmega64的直流电动机软起动器设计

直流电动机是重要的生产设备，起动是影响其寿命的关键因素。以蓄电池系统供电的直流电动机为研究对象。设计一种靠单片机控制，以IGBT为功率开关元件，采用PWM斩波降压的新型软起动器。相比传统的机械式起动器，它能实现连续无级的调节电动机起动，冲击转矩和冲击电流小，起动重复性好。     

饲料中动物源性成分微流控检测芯片的研究

试验以"LAMP+微流控"技术为基础,开发饲料动物源性成分检测芯片。针对牛、羊、猪、鸡的16srRNA靶序列,根据LAMP引物设计软件进行4种肉类LAMP引物设计。在LAMP优化试验、芯片优化测试、特异性验证试验和芯片应用测试中,进行最佳引物筛选测试和特异性测试。结果显示,筛选出的4种肉类最佳引物特异性强,最佳反应温度为65℃。芯片特异性验证试验的归一化荧光曲线显示,试验结果准确、特异性稳定。对饲料市场购买的16份样本中检测出的动物源性成分,采用中华人民共和国农业行业标准验证,符合率100%。微流控检测芯片的开发与应用为饲料中动物源性成分检测提供新方法,为饲料产品质量安全提供保障。     

单片机技术在自动给料系统中的应用

文章设计了基于单片机控制的送料机自动送料机控制系统,论述了单片机AT89C51在实现其生产过程控制的自动给料系统的设计方法。