不同染色体倍性小麦分蘖期氮同位素组成的研究

研究不同染色体倍性小麦分蘖期氮同位素组成 ( 15N )的变化。 [方法 ] 以不同染色体倍性小麦及不同抗旱性小麦为试 验材料, 采用 EA D elta pluse质谱仪测定并研究了小麦叶片、根系和整株氮含量、 15N的变化。 [结果 ] 随着染色体倍性的增加 ( 2n 6n), 小麦整株 15N呈增加趋势, 整株 15N更能代表小麦生长过程中氮的分馏情况; 现代小麦整株 15N与其收获性状有关, 即高产小麦 的 1 5N较低。 [结论 ] 该研究可为选择高氮利用效率小麦提供理论依据

冬小麦生长期氮同位素组成对温度的响应

研究了在田间持水量为70%～80%的水分控制条件下,黄土高原冬小麦(小偃6号)生长期氮同位素组成对温度变化的响应。结果表明:水分充足条件下,小麦生长期的温度变化范围为-2.2℃～21.7℃,植物氮同位素值的变化范围为-8.1&permil;～-1.6&permil;,在整个生长期,小麦氮同位素值和温度的变化具有正相关关系,即温度较高时,小麦氮同位素值亦较高,而低温导致小麦氮同位素值下降。这是小麦生理变化和土壤有效氮源对温度变化共同响应的表现,该结果为理解氮同位素组成和气候变化之间的关系提供了新的证据。</p

江汉平原钟桥遗址地层揭示的史前洪水事件

通过野外考古调查研究,利用对钟桥遗址疑似古洪水层和研究区现代洪水沉积物的锆石微形态、粒度、磁化率、Rb/Sr等地球化学指标的比较、AMS14C技术和考古器物断代,发现钟桥遗址在4800~4597 cal. a BP、4479~4367 cal. a BP和4168~3850 cal. a BP分别经历了三次古洪水事件并相应堆积了古洪水沉积层;结合江汉平原及其周边地区众多遗址的古洪水沉积层时代对比证据,揭示了屈家岭文化中晚期（4900~4600 cal. a BP）和石家河文化末期至夏代（4100~3800 cal. a BP）两次大洪水事件在江汉平原地区非常普遍。对史前洪水发生环境背景的进一步分析,反映江汉平原在5000~4500 a BP及4000 a BP前后的时段气候表现得不稳定,古洪水事件与气候环境变化驱动的江汉平原湖群扩张存在一定的联系,并影响区域新石器文化兴衰过程。同时,其它证据也表明该区社会发展过程和环境变化过程特别是古水文过程的矛盾在石家河文化末期已特别突出,发现具有全球意义的4000 a BP前后气候异常引起的大洪水事件是江汉平原地区石家河文化消亡的重要环境因素;而石家河文化末期该区内部或同中原以及其它地区间的冲突,都加速了石家河文化的崩溃。这些研究成果,提供了可靠的大禹时代史前洪水证据来说明其对新石器文化兴衰的社会影响,对于揭示4000 a BP气候事件中区域气候水文变化的响应规律,亦具有重要的科学意义。</p

典型工业城市土壤黑碳含量、分布特征及来源分析——以黄石市为例

以黄石市3种不同类型土壤(红壤土、潮土、水稻土)为研究对象,采用热光反射法测定土壤中黑碳、焦炭和烟炱含量,研究有机碳、黑碳、焦炭和烟炱的空间分布特征,同时分析黑碳、焦炭、烟炱与有机碳之间的相互关系及黑碳的可能来源.结果表明:黄石市表层土壤中黑碳含量的变化范围为0.01~5.79 g/kg,平均值为1.06g/kg.其中水稻土黑碳含量最高,潮土次之,红壤最低.黑碳在有机碳中所占比例的变化范围为0.53% ~ 89.54%,平均值为25.29%,说明黑碳对土壤有机碳库有较大的贡献.不同土壤类型黑碳/总有机碳(BC/TOC)比值存在较大的差异,红壤BC/TOC平均值最大(36.70%),其次为水稻土(25.25%),潮土最低(18.25%),这可能与土壤质地有关.黑碳、焦炭与烟炱含量和BC/TOC比值的空间变异性与区域的产业结构及工业布局有关.黑碳、焦炭与烟炱含量之间呈显著正相关,说明它们可能有共同的来源.焦炭/烟炱比值(char/soot)分析结果表明土壤中的黑碳受人为源的影响很大,主要来源于化石燃料燃烧(工业燃煤及机动车尾气排放).</p

对延安黄土沟壑区农业可持续发展的建议

黄土高原是中国农业文明的发源地，该区总面积大约 64 万平方公里，养育了约 1 亿人口。 新中国成立以来，党和国家十分重视黄土高原可持续发展问题。为了进一步巩固退耕还林（草） 工程取得的成效，帮助老区人民尽快脱贫致富，发展现代农业， 2013 年国土资源部、财政部等 批准在延安市实施治沟造地重大工程，总规模 50.67 万亩，总投资 51.72 亿元。 2015 年，全市累 计完成治沟造地面积 21 万亩，取得了显著成效。但是，目前仍有许多地方需要进一步改进，建 议坚持造田不毁林的原则，增加造地成本投入，建设高质量农田，科学管理提高效益，科学评估、 稳妥推广，以促进黄土高原地区农业可持续发展。</p

黄土关键带深层土壤水分动态模拟与主控因素

地球关键带是维系地球生态系统功能和人类生存的关键区域,土壤水分是黄土高原关键带植被恢复与生态环境重建的关键因子之一。为探明黄土关键带深剖面土壤水分变化过程并进行模型模拟,对黄土高原长武塬区苹果地和小麦地的深层土壤水分(0~18m)进行监测(2011~2013年,共选择11个不同日期进行深剖面土壤水分监测),在此基础上,采用Hydrus-1D进行模型模拟,分析了深剖面土壤水分动态及其模拟效果的主控因素。结果表明:1)苹果地(6~18m)、小麦地(3~18m)的深层土壤含水量随时间变化很小;0~1m的土壤含水量随时间变化较大;不同土地利用类型会产生不同的土壤水分过程及运动机制;在根系及近根系区,土壤含水量变化受根系分布格局及土壤质地共同影响,接近地表时还同时受降雨、蒸发等上边界条件影响;在非根系区,土壤含水量的主要影响因素为土壤质地;2)利用前6次的实测数据进行调参和校正,后5次实测数据进行预测效果检验,取得了较好的深剖面土壤水分模拟效果&mdash;&mdash;苹果地的决定系数、相对误差绝对值、均方根误差分别介于0.5923~ 0.7637、3.33%~5.20%、0.0149~0.0168cm~3/cm~3之间,小麦地分别介于0.2414~0.6822、2.64%~4.58%、 0.0177~0.0247cm~3/cm~3之间;3)叶面积指数、根系深度与分布是影响深剖面土壤水分动态模拟效果的主控因素。相关结果可为黄土关键带深剖面土壤水分模拟与调控提供参考。</p

基于EDEM的单轴螺旋榨油机工况分析与参数优化Working condition analysis and parameter optimization of single stage screw press based on EDEM

为了提高螺旋榨油机的日处理量，利用EDEM软件对6YL-76型单轴螺旋榨油机传输挤压段的工作过程进行仿真分析，以油菜籽-油液混合物颗粒群沿榨螺径向的合成速度波动幅度来表征颗粒的混合搅拌效果，并以合成速度波动幅度和日处理量为指标，对榨螺深度和榨圈圆弧半径进行了两因素三水平全面试验，建立了榨螺深度、榨圈圆弧半径与日处理量的回归模型并进行参数寻优，综合考虑合成速度波动幅度和日处理量得到最优值。结果表明：运用仿真试验对于研究螺旋榨油机内部工况具有优越性；螺旋榨油机日处理量随榨螺深度和榨圈圆弧半径增大有不同程度的提高；油菜籽-油液混合物颗粒合成速度波动幅度由榨螺深度主导；榨螺深度和榨圈圆弧半径的最优组合为榨螺深度12 mm，榨圈圆弧半径 6 mm。在优化条件下，6YL-76型单轴螺旋榨油机的日处理量提高了18.26%，其工作性能得到较大幅度提升。 In order to improve the daily processing capacity of the screw press, EDEM software was used to simulate the working process of the transmission extrusion section of 6YL-76 single stage screw press. The mixing and stirring effect of the particles was characterized by the fluctuation amplitude of the synthetic speed of the rapeseed-oil mixture particles group along the radial direction of the screw. The fluctuation amplitude of the synthetic speed and the daily processing capacity were taken as indicators, a two-factor, three-level comprehensive test was carried out on the worm depth and the circular arc radius of the pressure ring, and the regression model between the worm depth, the circular arc radius of the pressure ring and the daily processing capacity was established and optimized to obtain the optimal value by taking into account the fluctuation amplitude of the synthetic speed and the daily processing capacity. The results showed that the simulation test had advantages for studying the internal working conditions of the screw press；the daily processing capacity of the screw press increased with the increase of the worm depth and the circular arc radius of the pressure ring; the fluctuation amplitude of synthesis rate of rapeseed-oil mixture particles was dominated by the worm depth; the optimal combination of worm depth and circular arc radius of the pressure ring was 12 mm and 6 mm, respectively.Under the optimal conditions, the daily processing capacity of the 6YL-76 single stage screw press increased by 18.26% and its working performance was improved more significantly

会宁胡麻油产地环境及产品特征 Production environment and product characteristic of Huining flaxseed oil

为提高会宁胡麻油品牌知名度和影响力，探究了地理标志产品会宁胡麻油的产地环境、种植方式及生产管理过程和品质特性。以会宁县17个乡镇的土壤和胡麻油为试验材料，采用国家相关标准对产地环境及胡麻油品质进行分析并采用气相色谱-质谱法对胡麻油风味物质进行分析。结果表明：会宁胡麻油的产地环境和产品安全指标均达到绿色食品标准；会宁胡麻油中α-亚麻酸平均含量为54.24%，不同产地间存在一定差异；会宁胡麻油含有65种风味物质，香味浓郁，其中己醛、正己醇、2-甲基吡嗪、γ-己内酯和3-甲基巴豆腈对会宁胡麻油独特的香味有重要影响。综上，会宁胡麻生长环境好，会宁胡麻油香味浓郁、营养价值高。In order to improve the brand awareness and influence of Huining flaxseed oil, the production environment, cultivation method and production management process, and quality characteristics of Huining flaxseed oil, a geographical indication product, were explored.The soil and flaxseed oil from 17 townships in Huining county were used as test materials, and the production environment and product quality were determined by the relevant national standards, and the flavor compounds of flaxseed oil were determined by GC-MS method.The results showed that the production environment and product safety indicators of Huining flaxseed oil could meet the standards of green food; the average content of α-linolenic acid in Huining flaxseed oil was 54.24%, moreover, there was difference among different townships.Furthermore, the flaxseed oil of Huining contained 65 flavor compounds and had aromatic flavor, of which hexanal, hexyl alcohol, 2-methylpyrazine, γ-caprolactone, and 3-methyl crocetonitrile had important effect on the unique scent of Huining flaxseed oil.In summary, the flaxseed of Huining grows in a good environment and the oil has a rich aroma and high nutritional value

原料压榨制油的预处理方式对核桃多肽功能特性 和ACE抑制活性的影响Effect of raw material pretreatment method in oil pressing on functional characteristics and ACE inhibitory activity of walnut polypeptide

旨在研究原料压榨制油的预处理方式对核桃多肽性质的影响。对核桃仁分别进行未预处理、去衣、焙烤预处理后，进行压榨提油，以提油后的饼为原料，经正己烷脱脂，碱性蛋白酶酶解制备核桃多肽，测定核桃多肽的功能特性和ACE抑制活性。结果表明：与未预处理、焙烤预处理比较，去衣预处理的核桃多肽的持水性(50 ℃，5.11 g/g)、吸油性(50 ℃，3.25 g/g)、乳化性(pH 9.0,6257%)、乳化稳定性(pH 9.0,84.51%)、起泡性(pH 9.0,117.49%)及ACE抑制率（63.04%）最高。综上，以去衣预处理压榨制油后的核桃饼为原料制备的核桃多肽具有良好的功能特性和ACE抑制活性。The aim was to study the effect of pretreatment methods of raw material pressing for oil on the properties of walnut polypeptide. The walnut kernels were untreated, peeled and roasted respectively,then pressed to extract oil.The cake after oil extraction was defatted by n-hexane and hydrolyzed by alkaline protease to produce walnut polypeptide, and the functional properties and ACE inhibitory activity of walnut polypeptide were determined. The results showed that compared with no treatment and roasting pretreatment, walnut polypeptide obtained by peeling of raw material had the highest water holding capacity (50 ℃, 5.11 g/g), oil absorption (50 ℃,3.25 g/g), emulsifying ability (pH 9.0, 62.57%), emulsifying stability (pH 9.0, 84.51%), foaming ability (pH 9.0, 117.49%) and ACE inhibitory rate( 63.04%). In conclusion, the walnut polypeptide prepared from walnut cake after peeling and pressing for oil production had good functional properties and ACE inhibitory activity