不同播种期对甜菜产质量的影响

甜菜在苗期及出苗后能耐－５℃的代温，适时提早播种，甜菜前期叶面积增大１５．６％－２６．６％，可提高块根产量１０．８％－１６．０％。     

Aerial Assessment of Ephemeral Gully Erosion from Agricultural Regions in the Pacific Northwest

Soil erosion from agricultural areas continues to be problematic in terms of both financial and environmental measures. Ephemeral gullies contribute to the soil loss both by the volume of sediment eroded from the gullies and because they act as delivery channels for surface erosion. High resolution aerial imagery was used to quantify the amounts and locations of ephemeral gullies in the subbasins of the Potlatch River system. Areal ephemeral gully erosion rates varied from 33.6?mt/km2 (0.15 U.S. t/acre) in the Big Bear Creek Subbasin to 88.4?mt/km2 (0.39 U.S. t/acre) in the Middle Potlatch Creek Subbasin representing 2.3–7.7% of the total surface sediment load. An erosion potential index was proposed to assist resource managers predict gully locations at the watershed scale using readily available remote sensing and geographic information system layers.     

Dislocation dynamics simulations of precipitation hardening in Ni-based superalloys with high γ′ volume fraction

The flow stress of Nickel-based γ/γ′ superalloys containing up to 73 vol.% of Ni₃Al precipitates is calculated by dislocation dynamics simulations of a dislocation pair gliding on {111} planes, for temperatures up to 1000 K. It is calculated for different composition-related parameters (friction stress and APB energy), as well as for different microstructural parameters (channel width, precipitate volume fraction and the geometry of the intersection of the {111} glide plane with the precipitate). The emphasis is on the bowing-assisted cutting regime, which is the prevalent deformation mechanism observed in the simulations.     

Al-Zn-Mg-Cu铝合金变温双级蠕变时效模型

针对Al-Zn-Mg-Cu合金变温双级蠕变时效过程,建立了一种考虑蠕变应变与屈服强度的本构框架,通过实验数据的简单拟合方法获得了模型参数。模型不仅以简单的形式具备了处理蠕变时效过程中的应力松弛、强化响应和温度变化的能力,而且能够应用到有限元软件中模拟构件的蠕变量、屈服强度和回弹。模型结果不仅能够适应不同外加应力下实测的蠕变应变曲线,且有限元模拟结果与实测结果能够很好地吻合。     

过硫酸铵催化合成乙酸异戊酯反应时间的探讨

用过硫酸铵作催化剂,改变反应时间和不用带水剂合成乙酸异戊酯。结果显示:当反应时间为10min时,乙酸异戊酯的产率为83.07%;当反应时间为45min时,乙酸异戊酯的产率为93.58%;当反应时间为180 min时,乙酸异戊酯的产率为81.33%。实验得出,乙酸异戊酯产率最高的反应时间为45 min,最佳反应时间为40~50 min。     

Kinetic characterisation of an enriched Nitrospira culture with comparison to Nitrobacter

Nitrospira and Nitrobacter are nitrite-oxidising bacteria commonly identified in nitrogen removal wastewater treatment plants. Little is known about the growth parameters of Nitrospira or the effects of environmental conditions or inhibitory compounds on Nitrospira activity. These bacterial properties were investigated using an enriched Nitrospira culture and an enriched Nitrobacter culture or Nitrobacter literature values. Compared to Nitrobacter, Nitrospira was found to have a comparable optimal pH range (8.0-8.3); similar normalised activity-temperature relationship (0.44e(0.055(T-15))) for temperatures between 15 and 30 degrees C and a similar oxygen half-saturation constant, K(O) (0.54+/-0.14 mgL(-1)). The major differences identified were that Nitrospira had a lower nitrite half-saturation constant, K(S) (0.9+/-0.07 mgNO(2)-NL(-1)); lower inhibition threshold concentrations for free ammonia (between 0.04 and 0.08 mg NH(3)-NL(-1)) and free nitrous acid (less than 0.03 mg HNO(2)-NL(-1)) and a higher yield (0.15+/-0.04 g VSS g N(-1)). Therefore, Nitrospira is more likely to dominate nitrite oxidation under conditions with low ammonium and nitrite concentrations, which would provide an advantage to them due to their lower K(S) value while avoiding any free ammonia or free nitrous acid inhibition.     

汉中面皮水磨米粉的加工技术优化研究

目的为简化传统汉中面皮的生产工艺,对汉中面皮水磨米粉的生产加工技术进行优化。方法在保持汉中面皮传统风味口感的前提下,以出品率作为评价标准,选择大米的浸泡时间、水温、米水比例、搅拌速度4个因素进行单因素实验。在此基础上,通过正交实验对汉中面皮水磨米粉生产工艺条件进行优化,得出最佳工艺参数。结果通过正交实验获得的最佳工艺参数为:浸米时间4.5 h,水温20℃,浸泡米水比1:2.5(g:mL),搅拌速度30 r/min(搅拌1次/h,每次搅拌15 min)。使用此工艺参数生产水磨米粉的出品率为93.6%。结论优化了汉中面皮水磨米粉加工工艺,将汉中面皮的加工原料由大米改为水磨米粉,省去了大米浸泡和磨浆工序,省时省力,为消费者提供方便实用的产品。     

甘蔗新品种巴西45号对比试验

在巴西45号，新台糖25号，粤糖93-159和新台糖10号（CK）的对比试验中，巴西45号蔗茎产量比其余品种的增产均达到极显著水平；甘蔗蔗糖分以粤糖93-159的最高；单位面积蔗糖含量，以巴西45号的最高，比粤糖93-159的增糖达到显著水平，比其余2个品种的增糖达到极显著水平，表明巴西45号是一个难得的早熟高产高糖优良品种，应予以扩大示范表证，逐步推广应用。     

氮用量对湘西晒红烟生长发育、产量及品质的影响

研究了不同氮肥用量对晒红烟生长发育、养分含量、经济性状及品质的影响。结果表明:在0~150 kg/hm2的施氮量范围内,随氮肥用量的增加,晒红烟株高增加,叶面积扩大,烟株中总N、P和K含量升高,调制后烟叶产量、产值和上中等烟比例提高,烟叶中总氮、烟碱和蛋白质含量增加,糖含量下降。在中等肥力条件下,施氮量为150kg/hm2时,烟叶的烟碱含量较为适宜,香气较足,刺激性较小。     

用低线密度丝束生产细圆周滤棒研究

采用 3.33Y/3889(dtex/tex)规格的醋酸纤维丝束在AF2 /KDF2成形机上稳定生产出圆周为2 3.8mm、吸阻为 32 80～ 4 2 90Pa的细圆周滤棒。当增塑剂施加比例超过 8%时 ,滤棒硬度能达到国标要求。与采用 3.6 7Y/4 111(dtex/tex)规格的丝束相比 ,当采用该规格丝束生产的滤棒圆周为 2 3.8mm、吸阻为 32 80～ 4 2 90Pa时 ,可节约丝束 3.5 %～ 4 .8% ,过滤效率提高 1个百分点。