Net primary production and nutrient cycling in an apple orchard–annual crop system in the Loess Plateau,China: a comparison of Qinguan apple,Fuji apple,corn and millet production subsystems

In this study, we investigated net primary production (NPP) and nutrient cycling in an apple orchard–annual crop system located in the Hill and Gully Region of the Loess Plateau, which included four production subsystems: Qinguan apple, Fuji apple, corn and millet. The results showed that NPP of corn (Zea mays L.) was two to three times greater than for millet (Setaria Italica L.) or apples (Malus domestica Borkh., cv ‘Fuji’ and ‘Qinguan’). Annual nutrient uptake by corn and millet was also much larger compared to apple trees. A comparison of nutrient use efficiency based on economic product showed that P and K use efficiency for Qinguan apples was about 50% greater compared to corn, while there was little difference in N use efficiency between apples and corn. More than 94% of the nutrients taken up by annual crops were lost from the system through the removal of grain and above-ground crop residue. In contrast, apple harvest and tree pruning resulted in the removal of 10–50% of the nutrients taken up annually by apple trees. Calculations indicated that farmers applied 60 times more N and 33 times more P to Qinguan apple orchards than was removed by apple harvest, but the amount of N and P fertilizer applied to corn was slightly less than the amount of N and P removed through crop harvest. In summary, the results indicated that increasing the proportion of land planted to apples and convincing farmers to leave annual crop residue in the fields would increase the sustainability of the apple orchard–annual crop system. Additional work needs to be done to determine the fate of N and P fertilizer applied to orchards as well as optimum fertilization rates for each of the four crops in the apple orchard–annual crop system.     

苹果园的测土配方施肥技术

在一定的目标产量区间里,苹果园氮、磷、钾肥的施用量与土壤中氮、磷、钾养分含量呈负的线性关系：根据烟台地区苹果生产实践,总结提出了养分施用量与土壤养分含量、目标产量的线性函数公式,可方便求得苹果的适宜基、追施N、P2O5、K2O量。     

黄土高原土壤侵蚀预报模型研究进展

建立土壤侵蚀预报模型将为小流域综合治理、土地利用规划提供依据,为小流域水土保持效果有效评价提供参考。黄土高原坡面陡峭、破碎程度高、坡面水蚀模型复杂,水土流失的情况极为严重。通过对常用的数值模拟模型在黄土高原土壤侵蚀过程模拟中的适用性进行了对比和分析;结果表明经验模型模拟的精度更高,但是对侵蚀过程不能做出理论性的解释,而物理成因模型能够更好做到这一点。因此物理模型具有预测未来情景变化和解释气候变化、人类活动对土壤侵蚀响应的能力,可以为实现不同尺度流域的侵蚀动态模拟预报提供一定的理论基础。     

黄土高原土壤侵蚀预报模型研究进展

建立土壤侵蚀预报模型将为小流域综合治理、土地利用规划提供依据,为小流域水土保持效果有效评价提供参考。黄土高原坡面陡峭、破碎程度高、坡面水蚀模型复杂,水土流失的情况极为严重。通过对常用的数值模拟模型在黄土高原土壤侵蚀过程模拟中的适用性进行了对比和分析;结果表明经验模型模拟的精度更高,但是对侵蚀过程不能做出理论性的解释,而物理成因模型能够更好做到这一点。因此物理模型具有预测未来情景变化和解释气候变化、人类活动对土壤侵蚀响应的能力,可以为实现不同尺度流域的侵蚀动态模拟预报提供一定的理论基础。     

唑螨酯对土壤呼吸作用和过氧化氢酶活性的影响

通过模拟实验研究了杀螨剂唑螨酯对土壤呼吸作用和土壤巾过氧化氢酶活性的影响。结果表明,唑螨酯对土壤的呼吸作用有一定的影响,用1mg/kg剂量处理,初期土壤呼吸作用表现为轻微的抑制,到第15d则恢复到与对照一致。用5、10mg／kg剂量处理,则在培养期间内一直处于被抑制状态。唑螨酯对土壤中过氧化氢酶的活性有一定影响但不显著,在试验期间内,低浓度处理（1、10mg／kg）呈现出轻微的抑制-激活-恢复过程,而高浓度处理（40、80mg／kg）则呈现出抑制-激活-抑制-恢复过程。实验结果表明,唑螨酯对土壤微生物影响较小,属于低毒或无实际危害的农药。     

Structure variation in styrene-divinylbenzene copolymers and its influence on sorption properties

The effect of a series of solvents on the structure of solvent-modified styrene-divinylbenzene copolymers has been investigated. It has been found that by a consecutive treatment of these copolymers with toluene, acetone, methanol, and water marked changes can be brought about in the structure of these copolymers which lead to the formation of, or increase in, their specific surface area. This phenomenon was explained by the disintegration of large aggregates into smaller ones and the parallel formation of a larger number of small pores. Such a treatment enhances the sorption properties of the copolymers.     

Grazing intensity effects on soil nitrogen mineralization in semi-arid grassland on the Loess Plateau of northern China

Soil nitrogen transformation has been the subject of growing attention in many semi-arid grassland ecosystems. In our study, we employed an intact soil core in situ incubation technique and measured seasonal changes in soil net nitrogen mineralization and nitrification rates. The measurements were taken from the upper 0–10 cm soil layer of a permanent grassland during a growing season in a 8.5-year field experiment on the Loess Plateau, China that had four grazing intensities (0, 2.7, 5.3 and 8.7 sheep ha⁻¹). Our results demonstrate marked seasonal variations in inorganic nitrogen pools, net nitrogen mineralization and net nitrification. The rates of mineralization and nitrification were highest in August and lowest in September. No consistent differences in monthly net nitrogen mineralization and monthly nitrification rates were observed among the different grazing intensities. Sheep grazing stimulated nitrogen transformation, and the most stimulation occurred at a heavy grazing intensity of 8.7 sheep ha⁻¹. The mean soil net nitrification rate was positively correlated with the soil C/N ratio and pH. The mean N mineralization rate was negatively correlated with soil organic carbon, but was positively correlated with the soil C/N ratio. Our study demonstrated net nitrogen mineralization and nitrification rates were strongly linked to grazing intensity, soil temperature and moisture content.     

盐水精制过程及影响因素

综述了盐水精制过程,浅析影响因素,结合澄清桶内盐水净化过程,探讨提高出力和净化效果的一些措施。     

浅析粗对苯二甲酸产品透光率及其影响因素

简要阐述了CTA产品的透光率与PTA产品b值的相互关系,通过控制CTA的透光率,可保证PTA的b值,达到提高PTA产品品质的目的。结合生产实际,分析了PX纯度、氧分压、反应停留时间、反应器回流、母液循环率、二次氧化、无机杂质等对透光率的影响规律。     

导叶式旋流器内油滴的聚结破碎及影响因素

利用流场测试实验和模拟计算对导叶式旋流器的内部流场和湍流性能进行研究,得到导致旋流场中油滴发生聚结破碎现象的内因为时均速度梯度引起的黏性剪切力和湍流流动引起的高剪切应力及湍动能,并分析了油滴破碎的主要发生部位。同时为宏观考察导叶式旋流器内油滴聚结与破碎相对作用强弱,验证了旋流器的分离性能作为表征量的可行性,并在此基础上,利用导叶式旋流器的分离性能实验结果对油滴聚结破碎发生的外因进行研究,结果表明导向叶片的结构参数（叶片数和叶片出口角）和旋流器的操作参数（入口流速、溢流率、分散相入口浓度和操作温度）均会影响到油滴在旋流器中的存在和运动形态。     

双气泡间的聚并时间测量及其影响因素

聚并时间是研究气泡聚并行为过程中的一个重要参数。在消除气泡生长速度对聚并时间影响的条件下,利用自行开发的光学测试技术对双气泡间的聚并时间进行了精确的测量。考察了气泡尺寸、靠近速度、有机溶质的扩散、电解质和表面活性剂的加入对气泡聚并行为的影响。实验结果表明,双气泡间的聚并时间随着气泡直径的增加、气泡老化时间的延长、靠近速度的减小和有机溶质浓度的增大而增加。     

聚二甲基硅氧烷的改性技术及其渗透汽化性能的影响因素

介绍了聚二甲基硅氧烷(PDMS)的改性技术,总结了不同改性方法在渗透汽化中的应用,分析了影响PDMs膜渗透汽化性能的影响因素,指出了PDMs膜存在的问题及其发展方向.     

丙溴磷在苹果和土壤中的残留研究

为了安全合理的在苹果上使用丙溴磷,于2015²016年在山西太原市、运城市进行该药的残留田间试验,采用GC-FPD检测器进行定量分析。结果表明,丙溴磷在苹果和土壤中的半衰期分别为11.5 d和11.9 d。施药剂量1002016年在山西太原市、运城市进行该药的残留田间试验,采用GC-FPD检测器进行定量分析。结果表明,丙溴磷在苹果和土壤中的半衰期分别为11.5 d和11.9 d。施药剂量100²00 mg/kg,施药1和2次,药后56,63 d,苹果中丙溴磷的残留量<0.01200 mg/kg,施药1和2次,药后56,63 d,苹果中丙溴磷的残留量<0.01⁰.028 mg/kg,均低于中国规定的丙溴磷的最大残留限量值0.05 mg/kg。按照推荐药剂量200 mg/kg,施药次数不超过2次,安全间隔期为7 d,不会对苹果和土壤造成残留污染。     

黄土高原管道工程植被恢复设计

黄土高原区生态环境比较脆弱,水土流失严重,管道工程建设使生态环境进一步恶化。分析长庆油气田所处黄土高原区的气候、地形地貌、植被以及管道工程特点,提出针对黄土高原区管道工程植被恢复的原则、措施以及植被恢复设计,为后期新建油气田管道工程的植被恢复提供思路和借鉴。     

UV厌氧胶的制备及其影响因素研究

以聚氨酯丙烯酸酯(PUA)为基体、甲基丙烯酸-β-羟乙酯(HEMA)为活性稀释剂、异丙苯过氧化氢(CHP)为引发剂、N,N′-二甲基苯胺为促进剂、糖精为助促进剂、二苯甲酮(BP)/叔胺为光引发剂和对苯二酚为稳定剂,采用双引发体系和双固化[UV(紫外光)、厌氧固化]体系制备PUA基UV厌氧胶。通过单因素试验法优选出制备UV厌氧胶的最佳工艺条件。结果表明:当w(HEMA)=20%、w(CHP)=2%、w(光引发剂)=3.0%、w(N,N′-二甲基苯胺)=w(糖精)=0.8%和w(对苯二酚)=0.06%时,UV厌氧胶的综合性能良好,其光固化定位时间为8 s、剪切强度超过5 MPa。     

复合肥料的吸湿性及其影响因素

通过对复合肥吸湿性能的测定,得出各种配方复合肥的临界相对湿度,并对复合肥临界相对湿度与物料温度、原料成分之间的关系进行了研究,指出硝基复合肥的临界相对湿度受m(硝铵)/m(磷铵)的影响明显。     

丙溴磷在苹果和土壤中的残留研究

为了安全合理的在苹果上使用丙溴磷,于2015~2016年在山西太原市、运城市进行该药的残留田间试验,采用GC-FPD检测器进行定量分析。结果表明,丙溴磷在苹果和土壤中的半衰期分别为11.5 d和11.9 d。施药剂量100~200 mg/kg,施药1和2次,药后56,63 d,苹果中丙溴磷的残留量0.01~0.028 mg/kg,均低于中国规定的丙溴磷的最大残留限量值0.05 mg/kg。按照推荐药剂量200 mg/kg,施药次数不超过2次,安全间隔期为7 d,不会对苹果和土壤造成残留污染。     

PET连续固相缩聚工艺及主要影响因素

介绍了大连合成纤维研究设计院自主研发的10 kt/a连续式固相缩聚技术的生产工艺。从切片形状、结晶度及结晶形态、缩聚前预热、缩聚时间、氮气的纯度及流量等方面,讨论了固相缩聚主要影响因素。     

煤系高岭土脱硅的影响因素研究

碱选择性浸取煅烧高岭土提高铝硅比是目前煤系高岭土研究的一个新方向。本文系统研究了煅烧温度、保温时间、液固比、NaOH质量分数、浸取时间、脱硅次数及原料产地对煤系高岭土脱硅效果的影响,得出最佳脱硅条件,并在此条件下制备出铝硅比为4．62的脱硅高岭土。