氨基酸硒叶面肥在玫瑰香葡萄上的应用效果

以6年生玫瑰香葡萄为试材,对氨基酸硒叶面肥的应用效果进行了全面调查。结果表明,喷施氨基酸硒叶面肥可显著改善叶片质量,提高叶片叶绿素a、b和叶绿素总含量,使叶绿素b/a比值显著升高,增强叶片的耐弱光能力;提高叶片净光合速率,延缓叶片衰老;增强抗病能力,提高枝条成熟度,增强植株越冬能力;显著改善果实品质,使果实成熟一致性增强。     

溶液化学条件及吸附剂表面性质对Ni(II)在莱阳膨润土中吸附行为的影响

The effects of solution chemistry conditions and adsorbent surface properties on the adsorption behavior of Ni(II) on Lai'yang bentonite were investigated via batch technique. Potentiometric and mass titration techniques were employed in batch experimental methods, and results showed that the point of zero net proton charge (PZNPC) of bentonite at different ionic strengths presented pHPZNPC to be 8.2 ± 0.1. The removal of Ni(II) from solution increased with increasing bentonite dosage, with a maximum removal efficiency of up to 99%. The adsorption of Ni(II) on bentonite increased with increasing pH at pH< 8.5, maintaining a removal efficiency of > 99% at pH> 10.2. Ni(II) adsorption exhibited different responses to cations (K+, Na+) but was not influenced by background anions (NO3-, Cl-, and ClO4-). The adsorption of Ni(II) was dominated by outer-sphere surface complexation and ion exchange with Na+/H+ on bentonite surfaces at low pH, whereas inner-sphere surface complexation and surface precipitation were the main adsorption mechanisms at high pH. The adsorption isotherms of Ni(II) on bentonite can be described well by the Langmuir model. The thermodynamic parameters of adsorption, including Gibbs free energy, enthalpy change, and entropy change, at different temperatures indicated that the adsorption of Ni(II) on bentonite was endothermic and spontaneous.     

北京市怀柔312铁路专用线先张法简支梁预应力损失计算

结合北京市怀柔312铁路专用线所属标段中一座跨铁路的公路桥(3×8m)预应力混凝土简支梁桥施工过程对先张法预应力损失的检算,确定了简支梁桥单片梁在张拉过程中理论的预应力损失量,为施工张拉过程中确定张拉设备及张拉过程中张拉力的控制提供了必要的理论估算量。     

On Sensor Network Reconfiguration for Downtime-Free System Migration

Many state-of-the-art wireless sensor networks have been equipped with reprogramming modules, e.g., those for software/firmware updates. System migration tasks such as software reprogramming, however, will interrupt normal sensing and data processing operations of a sensor node. Although such tasks are occasionally invoked, the long time of such tasks may disable the network from detecting critical events, posing a severe threat to many sensitive applications. In this paper, we present the first formal study on the problem of downtime-free migration. We demonstrate that the downtime can be effectively eliminated, by partitioning the sensors into subsets, and let them perform migration tasks successively with the rest still performing normal services. We then present a series of effective algorithms, and further extend our solution to a practical distributed and localized implementation. The performance of these algorithms have been evaluated through extensive simulations, and the results demonstrate that our algorithms achieve good balance between the sensing quality and system migration time.

基于动态双重网格下喷动床滞止区流动特性CFD-DEM数值模拟

基于Fortran语言自行开发了基于动态双重网格方法下的喷动床内气固两相流动的CFD-DEM方法,同时开展了喷动床内径向混合实验与模拟研究,又结合单网格方法对喷动床内0~2.0 s内的滞止区特性进行对比分析,验证了动态双网格方法计算结果的准确性。然后利用动态双网格方法对不同进口气速下和不同初始堆积高度下的喷动床进行数值模拟研究,对滞止区颗粒流动过程进行追踪,结果表明：径向混合实验结果与数值模拟结果有很好一致性;在喷动床内存在一定的滞止区,滞止区内的颗粒流动性较差;初始堆积高度不变,随着进口速度的增加,滞止区高度下降速率和向喷口延伸速度无明显变化;进口速度不变,随着初始堆积高度的增加,滞止区颗粒下降速度随之增加,但其向喷口延伸速度逐渐变慢。     

油气由断裂向砂体侧向分流能力定量评价方法——以渤海湾盆地饶阳凹陷留楚构造为例

在油田勘探中,判断油气由断裂垂向运移后侧向分流的优势层位十分重要,但目前缺少有效的评价方法。以渤海湾盆地饶阳凹陷留楚地区为例,在综合分析盖层厚度和断-砂接触面积等影响油气侧向分流能力因素的基础上,利用储层地震反演等地球物理技术建立了主要影响因素的求取方法,并系统分析圈闭充满度与各因素之间的相关性,优选出有效影响因素,然后综合有效因素建立断-砂侧向分流能力定量评价公式。结果表明：当断-砂侧向分流系数R大于0.3时开始发生油气侧向分流,并且R越大圈闭充满度越高,当R大于0.9时油藏为纯油层。利用断-砂侧向分流系数对f038和f008两条断层的侧向分流情况进行验证,结果与实际钻井情况吻合较好。     

断层对地应力场方向的影响机理

断层附近区域地应力方向相对于远离断层区域存在明显变化。前人利用实验及有限元模拟等手段研究了断层对其附近区域地应力方向的影响规律,但是缺少从力学机理角度解释这些规律的研究。研究总结了单一断层附近最大水平主应力方向变化规律,利用孔口问题弹性力学解析解揭示了这种规律的力学机理,并以某单元为例,研究了多断层区域最大主应力方向沿断层走向上的变化。结果表明,断层端部区域最大水平主应力朝着断层走向偏转,应用孔口问题弹性力学求解可以获得理论证明,塔河某单元的地应力计算结果也验证了这种规律。     

原位合成微结构自组装高水热稳定介孔分子筛的研究进展

针对介孔分子筛水热稳定性较差这一关键问题,从原位合成β、ZSM 5、SAPO n、Y、L沸石微结构单元等方面综述了原位合成不同微结构单元自构建合成高水热稳定性介孔分子筛的合成方法和研究现状,并系统分析了原位合成过程中不同微结构单元合成步骤中的关键因素及其对介孔分子筛水热稳定性的影响规律,阐释了微结构单元与介孔分子筛水热稳定性之间的关联度,探讨了原位合成微结构单元自构建高水热稳定性介孔分子筛的合成机理。     

Changes in quality of rainbow trout (Oncorhynchus mykiss) fillets preserved with salt and sugar at low concentrations and stored at 4°C

The effects of dry-curing with low concentrations of salt and sugar on the quality of rainbow trout (Oncorhynchus mykiss) fillets were studied over a 16-day storage period at 4°C. Physicochemical characteristics (total volatile base nitrogen (TVB-N), biogenic amines (BAs), ATP-related compounds and K value), microbial populations (total aerobic counts (TAC), H₂S-producing bacteria, Pseudomonas, Aeromonas, and lactic acid bacteria) and sensory (SA) indicators were analyzed. Fish samples were subjected to the following treatments: untreated (control), dry-cured with 1.3% salt (T1), and dry-cured with 1.3% salt that also contained 0.9% sugar (T2). SA indicated that the sensory quality of the control, T1, and T2 was unacceptable after 8, 12, and 12 days of storage, respectively. Moreover, the cadaverine concentration of treated samples was significantly lower (P < 0.05) than the control after storing for 8 days. T1 and T2 were significantly higher (P < 0.05) than the control in inosine 5-monophosphate (IMP) content from the 2th to 10th day. Cadaverine, putrescine, hypoxanthine, and TAC were correlated significantly (P < 0.01) with SA, and these seemed to be reliable indicators of fish quality. The results indicated that curing treatments extended the shelf life of rainbow trout fillets, which could be exploited by processors.     

Dynamic properties of high-density low-alloy PM steels

PM steels with density higher than 7.5?g?cm^?3 were prepared from binder-treated powder, and the effects of alloying elements and microstructure on dynamic performance were studied. Although the addition of 1.5?wt-% Cu improves the tensile strength, it impairs toughness of the alloy by the formation of low-toughness pearlite. The 0.5?wt-% Cr addition promotes the formation of Ni-rich martensite and bainite at the expense of pearlite, which is beneficial to strengthen and homogenise the microstructure. The 0.5Cr alloy exhibits improved tensile strength and fatigue strength without sacrificing impact toughness, which exhibits high potential to be used for dynamic and cyclic loading applications. The tensile strength and fatigue endurance strength under 10⁷ cycles of 0.5Cr alloy achieve 1350 and 562?MPa respectively, and impact energy is as high as 21.1?J. The enhanced fatigue life is attributed to the high density, smaller pore size, rounder pores and composite-like microstructure.