高掺量粉煤灰和矿渣高强混凝土抗渗性和抗冻性试验

采用粉煤灰和矿渣2种掺合料的40%和50%2种质量比例掺量,制备了高掺合料C50高强混凝土,并利用扫描电镜和X射线衍射技术分析了高比例掺合料对高强混凝土强度的影响,最后通过抗氯离子渗透试验和快速冻融试验综合分析了高掺合料C50高强混凝土的耐久性。结果表明:当复掺掺合料总质量占胶凝材料总质量的50%时,随着粉煤灰与矿渣掺入量比值的减小混凝土养护28 d强度有所增加;在掺合料总质量不变的情况下,混凝土的抗冻性和抗氯离子渗透性能均随着粉煤灰掺入量的增加和矿渣掺入量的减小而逐渐提升,但掺合料总质量的增加会降低抗氯离子渗透性能;采用抗冻耐久性指数与电通量的比值法可较好的综合评价高掺合料高强混凝土的耐久性,耐久性较好的适宜配合比为掺合料总量50%,粉煤灰与矿渣掺量比为4:1。研究可为高掺量粉煤灰和矿渣在高强混凝土中的应用提供依据,同时达到提高高强混凝土的经济性和节约资源的目的。     

高氯土壤条件下烤烟对 Cl– 通道抑制剂的生理响应

【目的】在我国部分烟区,土壤氯离子含量高是造成烟叶氯离子含量高的一个主要因素,困扰着当地优质烟草的生产。研究氯离子通道抑制剂对烤烟成熟期叶片生理指标的影响,可为生产中合理降氯提供一定的参考。 【方法】2015 年在河南科技大学采用盆栽土培试验,设置四个处理,分别为 200 μmol/L NFA、200 μmol/L 9-AC、200 μmol/L Zn2+ 和蒸馏水,土壤含氯量为 50 mg/kg。于移栽后 30、45、60、75 d 灌根,每个处理每次每盆灌 1 L,连灌 3 天。测定了成熟期烤烟中部功能叶片中的CLC-Nt2 基因表达强度、光合色素含量、叶绿素荧光参数、相关元素积累量以及烟株生物量。 【结果】1) 与对照相比,施用抑制剂 Zn2+、NFA、9-AC 的烟株叶片中CLC-Nt2 的表达量显著降低,分别为对照的 82.22%、75.39%、72.19%,但 3 组抑制剂处理之间无显著差异。2) Zn2+、NFA、9-AC 处理的叶片叶绿素总含量较对照分别增加 20.15%、29.10%、45.52%,差异达到显著水平。同时,经不同抑制剂处理的叶片叶绿素荧光特性也表现出不同程度的增加,表明抑制剂可以减缓氯含量对烤烟 PSⅡ光合机构的伤害。3) 抑制剂对烤烟叶片中 Cl–、K+、NO₃– 的积累有明显影响。与对照相比,抑制剂处理的 3 组叶片中 Cl– 含量显著降低,降幅在 18.17%～33.48%;K+ 含量和 NO₃– 含量明显提高,增幅分别为 5.28%～10.20% 和 12.19%～25.24%,其中以 9-AC 处理的效果最佳。4) 抑制剂对烤烟生物量的合成有促进作用。与对照相比,施用抑制剂后烟株叶、茎、总干重显著提高,增幅分别为 17.02%～32.45%、10.54%～20.66% 和 13.21%～25.50%;而根干重增加幅度较小,仅为 5.94%～11.43%,根冠比显著降低。抑制剂的作用效果表现为 9-AC > NFA > Zn2+ > CK。 【结论】当植烟土壤中氯离子含量较高时,外施氯离子通道抑制剂能够对烤烟植株生长及体内一系列生理活动产生积极作用,在一定程度上缓解了氯害对烟草的不利影响。在本试验条件下,施用 200 μmol/L 9-AC 的烟株整体表现最优,而施用 200 μmol/L Zn2+ 的处理在基本满足降低叶片氯离子含量的同时降低了生产成本,这为生产中合理降氯提供了一定的参考。     

絮凝剂对藻类后续厌氧消化过程的影响

[目的]研究絮凝剂对藻类后续厌氧消化过程的影响。[方法]对不同含固率条件下水华藻类的产沼潜力及聚合氯化铝絮凝剂对藻类消化的影响进行分析。[结果]水华藻类的产甲烷潜力较高,含固率为6.0%时单位有机质累积甲烷产量可达147.03 mL/g VS,但脱水过程中使用的聚合氯化铝会严重抑制厌氧消化过程,在较低含固率3.0%条件下,铝离子浓度达984 mg/L,产气量低于潜力值的60%。[结论]该研究为藻类厌氧消化处理提供参考,同时为调整藻类采收方法提供理论依据。     

Effects of taurine on plasma glucose concentration and active glucose transport in the small intestine

Taurine lowers blood glucose levels and improves hyperglycemia. However, its effects on glucose transport in the small intestine have not been investigated. Here, we elucidated the effect of taurine on glucose absorption in the small intestine. In the oral glucose tolerance test, addition of 10 mmol/L taurine suppressed the increase in hepatic portal glucose concentrations. To investigate whether the suppressive effect of taurine occurs via down‐regulation of active glucose transport in the small intestine, we performed an assay using the everted sac of the rat jejunum. Addition of taurine to the mucosal side of the jejunum suppressed active glucose transport via sodium‐glucose cotransporter 1 (SGLT 1). After elimination of chloride ions from the mucosal solution, taurine did not show suppressive effects on active glucose transport. These results suggest that taurine suppressed the increase in hepatic portal glucose concentrations via suppression of SGLT 1 activity in the rat jejunum, depending on chloride ions.     

氯盐侵蚀和干湿循环条件下浮石混凝土的耐久性

为了探究干湿循环条件下氯离子对浮石混凝土的侵蚀机制,借助核磁共振测试技术,分析浮石混凝土在干湿循环条件下微观孔隙结构特征,对侵蚀后的浮石混凝土内部微观结构进行X射线衍射物相分析与电镜扫描分析,进而探讨浮石混凝土抗氯离子侵蚀性能。研究结果表明,在氯盐侵蚀作用下,浮石混凝土和普通混凝土的质量损失变化率与相对动弹性模量变化趋势相一致;发现浮石混凝土谱面积是普通混凝土谱面积的1.0～1.7倍;浮石混凝土侵蚀破坏主要为内部发育新的小孔隙和中小孔隙向大孔隙和裂纹发育造成的,普通混凝土侵蚀破坏主要为内部的微小孔隙和小孔隙向大孔隙和裂纹发育造成的;浮石混凝土(0.1～1.0 μm孔隙所占比重较多,普通混凝土(0.01～0.1 μm孔隙所占比重较多;干湿循环120次后浮石混凝土孔隙度增加26.7%,自由流体饱和度减少1.0%,干湿循环120次后普通混凝土孔隙度增加77.8%,束缚流体饱和度减少7.3%;氯盐侵蚀后均生成以Friedel盐为代表的多种腐蚀结晶物。该研究可为浮石混凝土在氯盐环境下农业水利建设提供理论依据。     

Ammonium and nitrate transport during saturated and unsaturated water flow through sandy soils

Citrus production in Florida accounts for ≈ 60% of national production in USA. The sandy soil characteristic (> 95% sand) makes water and nutrient management extremely difficult, raising concerns about environmental sustainability as a result of nutrient inputs in citrus producing regions where sandy soils dominate. Thus, laboratory column and field experiments were conducted to better understand the leaching patterns of and ions in Florida's sandy soils. The soil columns were first saturated from the bottom with two pore volumes of simulated Florida rain followed by pumping a pulse of fertilizer mixture at a steady Darcy flux of 14 cm h^?1. Nitrate and Cl^? appeared earlier in the effluent than in the A and B_h horizons, due to cation exchange of . Essentially identical breakthrough curves (BTCs) for and were observed in the E‐horizon, due to very low sorption of . The convective and dispersive equilibrium (CDE) model simulations were in good agreement with measured breakthrough curves (BTCs) for , , and Cl^?. However, the sorption coefficient (K_D) values used in the CDE model to simulate the BTCs for were about 10 times less than the batch isotherm K_D values. This was attributed to differences in pH, cation composition, and ionic strength between batch (static) and dynamic (leaching) systems. The field experiment showed that under unsaturated flow, improved short‐pulse fertigation systems (drip and microsprinkler) limited and transport beyond the root zone (top 30 cm), which might have promoted nutrient and water uptake in citrus. The column study revealed that under extreme weather events such as hurricanes or storm surge in Florida, saturated soil conditions can trigger N mobility below the root zone to surficial or groundwater aquifers. In the field experiment, the use of judicious, minimal and split applications and accurate placement of N‐fertilizers reduced leaching of N especially during heavy storms in the summer rainy months of Florida. The field experiment demonstrated that it is possible to manage inorganic N forms for optimal residence time for uptake and minimal leaching concerns.     

增效缩节安化学封顶对棉花主茎生长的影响及其相关机制

缩节安(1,1-dimethyl piperidinium chloride, DPC)是棉花生产中广泛应用的植物生长延缓剂。增效DPC (DPC ⁺, 25%水剂)助剂中的成分能对植物幼嫩组织表面形成轻微伤害, 实践证明其可实现棉花化学封顶、起到替代人工打顶的作用。为探究DPC ⁺作用机制, 本试验于2015年在田间条件下研究了棉花盛花期后(7月24日)应用DPC ⁺ (1125 mL hm ^-2)对棉花主茎生长和顶芽解剖结构、氧化还原状态及相关基因表达的影响。结果表明, 与对照(同期喷施清水)相比, DPC ⁺处理后棉花株高降低, 白花以上节位(nodes above the last white flower, NAWF)更早降到5; 处理后3 d即可观察到主茎生长点较对照扁平, 生长点的纵横比显著低于对照; 处理后6 h棉花顶芽的O₂ ^-、H₂O₂和MDA含量高于对照, 而开花相关基因GhSPL3和GhV1及顶端分生组织相关基因GhREV3的表达量则低于对照。化学封顶剂DPC ⁺可引起棉株顶芽的短期氧化应激反应, 降低与主茎生长点发育和花芽分化相关基因的表达水平, 从而延缓棉株生长和花芽的产生, 实现化学封顶。     

Effects of Salinity on Growth,Water-Use Efficiency,and Nutrient Leaching of Three Containerized Ornamental Plants

The scarcity of water in the Mediterranean area has frequently led to the use of saline water to irrigate ornamental plants in nurseries. Aloe vera L. Burm, Kalanchoe blossfeldiana Poelln, and Gazania splendens Lem. plants were grown in a greenhouse from the University of Almeria in containers with a mixture of sphagnum peat moss and perlite in order to evaluate the effect of salinity levels on plant growth, water-use efficiency, and nutrient leaching. The experimental design consisted of three salinity treatments, four blocks, and four plants (one plant per container) per treatment-block giving a total of 12 plants per species plus border plants placed around the perimeter of the treatment plants to maintain uniform growing conditions for treatment plants. At the end of the experiment, plant dry weight and water-use efficiency were assessed for each salinity treatment. Leachate was collected weekly and analyzed for concentrations of nitrate-nitrogen, phosphate-phosphorus, potassium, calcium, and magnesium (NO₃^–N, PO₄^3–P, K⁺, Ca²⁺ and Mg²⁺). Increasing salinity levels of irrigation water reduced the plant dry weight in all species and affected the leachates volume and their nutrients concentrations. We suggest the use of low salinity levels in water to improve the growth and to reduce the environmental impacts of nutrient runoff.     

珠芽期不同措施对兰州百合生长的影响

通过对珠芽期兰州百合喷施矮壮素、磷酸二氢钾和摘花处理,探索不同措施对高温环境下兰州百合生长的影响。结果表明:喷施200 mg/L矮壮素、0.3%磷酸二氢钾和摘花处理都可增加兰州百合叶片厚度,降低叶片枯黄数量和枯黄程度,提高百合鳞茎鲜质量;其中,喷施矮壮素处理的效果优于喷施磷酸二氢钾和摘花处理;3种措施联合使用效果最好。