磁性液体的场致光透射驰豫回复性研究

用Massart法制备了Ni2O3/Fe2O3复合微粒磁性液体.测量了磁性液体在不同强度的外磁场作用下,沿磁场方向的光透射率随磁场通断而下降、上升的重复变化曲线.发现通磁场后光透射强度的下降速率与断磁场后光透射强度的回复速率随通断磁场重复次数变化,并趋于一致.从磁性液体的微结构变化探讨了导致这种现象的内在因素.     

卢氏鸡养殖现状及保种开发对策

为有效地保护卢氏鸡这一优良家禽遗传资源,并为其开发利用提供参考,介绍了卢氏鸡的特征特性;从原有的生物特性发生改变,保种场存在其他鸡种群,存在疾病垂直传播威胁等方面分析了保种存在的问题;从制定卢氏鸡保种与开发方案,鼓励企业投资开发、以促进保种,划定保种区、开展本品种选育,加强种质资源的疫病防控等方面提出了卢氏鸡保种与开发利用的对策。     

玉米温光敏雄性不育系9417叶片叶绿体蛋白质差异分析

对玉米温光敏感雄性不育-可育 “两用系”9417的不育型和可育型叶片中的叶绿体蛋白质组进行研究,试图找出不育型与可育型的差异蛋白,确定导致不育的蛋白。利用SDS PAGE凝胶电泳,对玉米雄性不育 可育“两用系”不育型与可育型8叶期功能叶叶绿体蛋白质组中的差异蛋白进行分析。结果表明,不育型与可育型存在3条蛋白差异条带,其中No.1条带为不育型中新出现的蛋白质条带,而其余两条条带只在表达丰度上有差别。利用MALDI TOF MS方法,运用MASCOT软件于NCBI数据库中进行数据查询,结果显示No.1条带中含有3种蛋白质,而这3种差异蛋白的出现可能与玉米不育性有关。     

转GhB301基因棉花响应枯萎病菌侵染的转录组分析

乙烯响应因子(ethylene responsive factor, ERF)可以激活或者抑制下游病程相关蛋白基因的表达,在植物抗病信号转导途径中发挥着重要作用。为探究ERF-B3亚组基因GhB301在棉花抗枯萎病中的分子调控机制,本研究利用已获得的转GhB301基因棉花株系,通过孢子悬浮液蘸根的方法对转GhB301基因棉花株系(N)和野生型对照(WT)进行接菌处理,抗病性鉴定结果表明,过表达GhB301的N株系增强了对枯萎病的抗病性,其病情指数为14.77,显著低于WT(病情指数为37.50);枯萎病菌侵染0、6、12、24、48 h后,利用RNA-seq技术对N和WT的根部组织进行测序分析,共得到273 111 170个clean reads,其Q30均大于87.64%,将clean reads与陆地棉参考基因组TM-1比对,获得了14 021个差异表达基因(DEGs)。与WT相比,转基因株系能够在病原菌侵染后更快速地做出响应。GO及KEGG富集分析发现共有135个DEGs参与氧化还原过程,67个DEGs参与防御反应,31个DEGs参与苯丙烷类生物合成,推测这些DEGs可能与转基因棉花的枯萎病抗性增强存在密切关系。本研究结果为阐明GhB301基因响应棉花枯萎病菌侵染规律奠定了基础。     

种肥播施方式对红壤旱地油菜产量及肥料利用率的影响

In order to explicit proper sowing and fertilizing methods of rapeseed production in red-soil dryland, a two-year field experiment covering two rapeseed seasons (2017-2018 and 2018-2019) was conducted with four treatments of sowing and fertilizing methods to analyze the impact on yield formation and fertilizer use efficiency of rapeseed, including conventional sowing and fertilizing method (T1), sowing in row with surface broadcast fertilizing (T2), synchronous sowing in uniform row with side deep fertilizing (T3) and synchronous sowing in wide-narrow row with side deep fertilizing (T4). The results were as follows: The yield and fertilizer use efficiency of rapeseed in red-soil dryland were significantly affected by sowing and fertilizing methods. Besides, these differences were more significant in poor soil condition and drought season (2017-2018) than those in nutrient-rich soil condition and rainy season (2018-2019). Compared with T1 and T2, T3 and T4 promoted the yield formation and increased its fertilizer use efficiency significantly, whereas there was no significant difference between T3 and T4. Specifically, the technique of synchronous drilling sowing with side deep fertilizing could improve dry matter production during the whole growth period of rapeseed, especially from anthesis to maturity, with a corresponding rise of dry matter accumulation of both underground and aboveground after anthesis. Meanwhile, compared with the conventional cultivation, the technique of synchronous drilling sowing with side deep fertilizing increased the uptake of nutrients (N, P and K), effective plant density and maintained sufficient pod number, and thus improved the yield and fertilizer use efficiency of rapeseed. This study indicated that the technique of synchronous drilling sowing with side deep fertilizing had the potential of improving rapeseed productivity in red-soil dryland of southern China. Therefore, it should be suggested to promote the application according to local condition.     

免耕与秸秆还田对中国农田土壤有机碳贮量变化的影响

农田碳汇管理措施的增汇效应是全球变化研究内容的重要命题之一.本文基于土地动态模拟系统(DLS)模拟了2012与2020年全国栅格尺度的农田分布,同时利用基于遥感反演的1988、2000年农田分布数据,应用CENTURY模型模拟了实施免耕、秸秆还田措施下中国1988～2020年农田土壤有机碳贮量的时空变化特征,分析了1988～2000年、2000～2012年与2012～2020年3个时段中国农田土壤有机碳贮量变化情况,揭示了九大农业生态区农田土壤有机碳贮量变化的时空分异特征.在不实施农田碳汇管理措施的情况下,1988～2000年全国大部分地区的农田土壤有机碳呈增长态势;而2000～2012年的全国农田土壤有机碳贮量出现一定幅度的下降.2012～2020年间,虽然全国范围内的土壤有机碳贮量表现为下降趋势,但下降幅度较2000～2012年间显著减少.研究结果表明,实施秸秆还田与免耕措施能够有效促进农田土壤有机碳贮量的增加,同时这两种管理措施的增汇效应具有显著的空间分异特征,黄淮海区、长江中下游区、华南区和西南区的增汇效果相对明显.上述研究结论为制订和实施农田增汇措施、减缓气候变化影响并保障农业发展的相关政策提供决策参考信息.     

新疆西昆仑地区泥石流灾害分析与评价

[目的]评价研究区泥石流的危险性,找出适合新疆西昆仑地区泥石流灾害研究的技术和方法。[方法]以新疆西昆仑山脉西段马尔洋地区为研究对象,在充分收集、研究前人资料和有效利用其他信息源的基础上,通过对研究区ETM+影像数据的研究,对研究区泥石流灾害点进行了判读。结合DEM数据,对该区地形地貌进行了研究。[结果]选取了合适的泥石流灾害危险性评价指标体系。一般危险区、中度危险区、高度危险区、极度危险区,面积分别为:31.69,40.70,38.31,25.83km2,所占比例分别为:23.21%,29.81%,28.06%,19.92%。[结论]研究区泥石流灾害极度危险区和高度危险区占总面积的47.98%,主要分布在研究区的中部和西北部区域,为泥石流灾害高度危险性易发区。     

长白山岳桦-暗针叶林过渡带根系呼吸对土壤总呼吸的贡献

Total and root-severed soil respiration rates for five plots set up 50 m apart in a Betula ermanii Cham.-dark coniferous forest ecotone on a north-facing slope of the Changbai Mountains, China, were measured to evaluate the seasonal variations of soil respiration, to assess the effect of soil temperature and water content on soil respiration, and to estimate the relative contributions of root respiration to the total soil respiration. PVC cylinders in each of 5 forest types of a B. ermanii-dark coniferous forest ecotone were used to measure soil respirations both inside and outside of the cylinders. The contribution of roots to the total soil respiration rates ranged from 12.5% to 54.6%. The mean contribution of roots for the different plots varied with the season, increasing from 32.5% on June 26 to 36.6% on August 3 and to 41.8% on October 14.In addition, there existed a significant （P 〈 0.01） logarithmic relationship between total soil respiration rate and soil temperature at 5 cm soil depth. Also, a similar trend was observed for the soil respiration and soil water content at the surface （0-5 cm） during the same period of time.     

低分子量骨胶原肽酶解制备工艺优化和特性分析

酶解工艺参数不仅会影响畜禽骨蛋白的酶解效率,而且会改变骨胶原肽产物的肽分子量分布、氨基酸组成和微结构性能,从而影响其高值高效化利用。以制备均一性低分子量骨胶原肽为目的,以牛骨粉为研究对象,以水解度为主要评价指标,考察碱性蛋白酶、中性蛋白酶、复合蛋白酶和风味蛋白酶对牛骨粉的酶解效果,探究双酶分步酶解工艺、脂肪酶预处理的单独与组合应用对酶解效果的提升作用,选定最优的低分子量骨胶原肽制备工艺;结合酶解过程中各项指标的变化、产物表征分析和Person相关系数法分析不同复合酶解工艺对产物特性的影响及作用机制。研究发现：经脂肪酶预处理-碱性蛋白酶-复合蛋白酶酶解工艺制备的骨胶原肽产物具有最佳的理化性质,优化的工艺参数为：底物质量浓度为0.09 g/mL、初始pH值7.5的牛骨粉溶液加入碱性脂肪酶（加酶量0.08%）在40℃下反应4 h,再加入碱性蛋白酶（加酶量0.36 U/g）在60℃下反应5 h后,最后加入复合蛋白酶（加酶量0.36 U/g）在55℃下反应5 h,此时,水解度可达16.12%,总游离氨基酸含量可达171.571 mg/g,其M_w、M_w/...     

Application of ANSYS to Finite Element Analysis for Nonlinear Masonry Structures

ANSYS has become an effective tool for finite element analysis of masonry structure, but there is few common conclusions for reference. According to the characteristics of ANSYS and the essence of the analysis, some key problems in finite element analysis of masonry structure with ANSYS, such as structural modelling, material constitution, the damage criterion, iterative algorithm, convergence criterion, simulation of prestressing force and so on, are discussed in this paper. Based on the test results of typical masonry structures, the applicability of ANSYS to masonry structural analysis is studied and some suggestions for the application of ANSYS are presented.