工程施工中土建与电气的专业配合

随着我国经济发展、科技进步和生活水平的提高,建筑工程功能更加完善、标准不断提高.文章那个针对目前现代化高层建筑土建专业与电气专业在施工中的专业配合不协调,根据两专业的特点、结合具体实例,阐述了应注意的问题及解决方法.     

NaCl胁迫下流苏的电阻抗与电导分析

以流苏2年生苗木为材料,测定其叶片与茎在NaCl胁迫(0,0.4％,0.8％,1.2％)下的电阻抗图谱参数和电导率的变化,分析电阻抗图谱参数与电导率间的相关性,以讨论在NaCl处理下用电阻抗图谱法研究流苏受胁迫程度的有效性.结果表明:1)随着NaCl浓度的升高,叶片电导率显现逐渐升高或先升高后下降的趋势,茎的表现不明显;随着胁迫时间的延长叶片和茎电导率,整体均显现逐渐升高或先升高后降低的趋势.流苏茎的耐盐性强于叶片.2)随着NaCl浓度的升高,流苏叶片和茎的高频电阻率r、胞内电阻率ri和弛豫时间Τ呈现先增大后减小或逐渐减小的特征;随着胁迫时间的延长叶片和茎的各处理的电阻抗图谱参数均在胁迫15天时出现最低值.相关分析表明:流苏对0.8％以上NaCl浓度胁迫敏感,用电阻抗图谱参数可以表征流苏受NaCl胁迫的程度,且用EIS参数胞内电阻率ri、高频电阻率r来表征叶耐盐特性,用胞内电阻率ri、弛豫时间Τ来表征茎耐盐特性.ri为评价流苏叶和茎NaCl胁迫的最佳参数.     

Electrical penetration graph evidence that pymetrozine toxicity to the rice brown planthopper is by inhibition of phloem feeding

BACKGROUND: Pymetrozine is a valuable novel insecticide for control of sucking insects, including the brown planthopper Nilaparvata lugens (Stål), one of the most serious pests on rice. This study was conducted to elucidate the action mechanisms of pymetrozine on the feeding behaviour of the planthopper. RESULTS: The activity test showed that pymetrozine primarily functioned as an antifeedant that caused starvation and death in N. lugens, rather than having neurotoxicity. Pymetrozine‐treated insects died at a significantly slower speed than insects treated with starvation. Electrical penetration graph (EPG) data indicated that pymetrozine significantly increased the duration of non‐probing periods and had a strong inhibition to phloem ingestion. The inhibition was strongly dose dependent, resulting in a complete suppression of the activity in the phloem region when the pymetrozine concentration was increased to 400 mg L^?1. Starvation caused by inhibition of phloem ingestion might be a major toxicity mechanism of pymetrozine. EPG data also showed that pymetrozine had no significant effect on stylet movement and duration of xylem sap ingestion. CONCLUSION: The study revealed that pymetrozine disturbed the feeding behaviour of N. lugens mainly by increasing the non‐probe period and inhibiting phloem ingestion. The inhibition resulted in a slow death similar to starvation. Copyright © 2011 Society of Chemical Industry     

动作电位控制的韧皮部物质卸出

对于敏感植物如含羞草(Mimosa pudica),当触摸叶片时,能激起叶枕运动细胞的膨压降低,动作电位上升,导致叶片合拢,刺激后,这些电位通过韧皮部运输对叶枕韧皮部物质卸出产生影响.利用放射性自显影的方法通过“C 物质(CO_2)观察韧皮部的位置,在未受刺激的叶枕,放射性物质显示的图象仅在韧皮部;然而,刺激后的叶枕~(14)C 物质主要集中在皮层的可伸长区域.由于刺激产生动作电位,因而认为,叶枕动作电位导致韧皮部糖类物质卸出.     

初始含水量对盐碱土饱和导水能力和盐分淋洗的影响

为了探究初始含水量对盐碱土饱和导水能力和盐分淋洗的影响,采用室内模拟试验,进行了6个不同初始含水量的定水头饱和导水能力试验。结果表明,盐碱土饱和导水率随初始含水量的增加而减小,二者呈显著的线性负相关;随初始含水量的增加,淋洗液pH值降低,电导率升高;随盐碱土饱和导水率的增大,淋洗液pH值升高,电导率降低,二者均与饱和导水率间呈对数关系。长期淹水状态下,盐碱土饱和导水能力平稳降低,盐分淋洗效果也变差。     

在盐水浇灌条件下堆肥对土壤性质、小麦生长以及作物营养的影响

A greenhouse experiment was conducted to test and compare the suitability of saline compost and saline irrigation water for nutrient status amendment of a slightly productive sandy clay loam soil,to study the macronutrient utilization and dry matter production of wheat(Triticum aestivum c.v.Gemmiza 7) grown in a modified soil environment and to determine the effects of compost and saline irrigation water on soil productivity.The sandy clay loam soil was treated with compost of five rates(0,24,36,48,and 60 m 3 ha-1,equivalent to 0,3,4.5,and 6 g kg-1 soil,respectively) and irrigation water of four salinity levels(0.50(tap water),4.9,6.3,and 8.7 dS m-1).The results indicated that at harvest,the electrical conductivity(EC) of the soil was significantly(P < 0.05) changed by the compost application as compared to the control.In general,the soil salinity significantly increased with increasing application rates of compost.Soluble salts,K,Cl,HCO 3,Na,Ca,and Mg,were significantly increased by the compost treatment.Soil sodium adsorption ratio(SAR) was significantly affected by the salinity levels of the irrigation water,and showed a slight response to the compost application.The soil organic carbon content was also significantly(P < 0.05) affected by application of compost,with a maximum value of 31.03 g kg-1 recorded at the compost rate of 60 m 3 ha-1 and the irrigation water salinity level of 8.7 dS m-1 and a minimum value of 12.05 g kg 1 observed in the control.The compost application produced remarkable increases in wheat shoot dry matter production.The maximum dry matter production(75.11 g pot-1) occurred with 60 m 3 ha-1 compost and normal irrigation water,with a minimum of 19.83 g pot-1 with no addition of compost and irrigation water at a salinity level of 8.70 dS m-1.Significant increases in wheat shoot contents of K,N,P,Na,and Cl were observed with addition of compost.The relatively high shoot N values may be attributed to increases in N availability in the tested soil caused by the compost application.Similarly,significant increases in the shoot contents of Na and Cl may be ascribed to the increase in soil soluble K and Cl.The increases in shoot P,N,and K contributed to the growth stimulation since P supplied by the compost was probably responsible in saline and alkaline soils where P solubility was very low.     

盐碱地咸水灌溉枸杞种植条件下土壤盐分变化

In order to utilize the wasted saline-sodic soils under shallow groundwater condition,a 3-year field study was carried in a field cropped with Lycium barbarum L.and irrigated by drip irrigation with saline groundwater under the water table depth of 30-40 cm in the northern Yinchuan Plain,China.Effects of cropping duration (one,two,and three years) on soil salinity,soil solution composition,and pH in three adjacent plots were investigated in 2008.Results showed that a high irrigation frequency maintained high soil water potential and subsequently facilitated infiltration and downward movement of water and salt in the crop root zone.Salt accumulated on the edges of the ridges,and soil saturated-paste electrical conductivity (ECe) was higher in the edge.Concentrations of Na+,Ca2+,Mg2+,Cl-,and SO42- in the soil increased with the soil depth as did the ECe,while HCO3- and pH had a relative uniform distribution in soil profile.As planting year increased,the ECe and soil salts in the field had a decreasing tendency,while in the root zone they decreased immediately after irrigation and then remained relatively stable in the following growing seasons.HCO3- and pH had little change with the planting year.Results suggested that the application of drip irrigation with saline water could ameliorate saline-sodic soil and provide a relatively feasible soil environment for the growth of salt-tolerant plant Lycium barbarum L.under the saline-sodic soils with shallow groundwater.     

Study on the impact of wastewater irrigation on the quality of oils obtained from olives harvested by hand and from the ground and extracted at different times after the harvesting

Nowadays, lots of efforts are made in Tunisia for the exploitation of wastewater in agriculture in order to face a very elevated mobilization of resources in water (90%). At Sfax, a Governorate placed in the South of Tunisia, the annual rainfall rarely exceeds 200 mm, so the climate is fairly arid. The significant water deficit can be reduced with the reuse of treated wastewater (TWW). The Sfax wastewater originated from the municipal wastewater treatment plant (WWTP) localized at 5 km in the south of Sfax, Tunisia. This WWTP is an aerated lagoon process receiving industrial wastewaters. Its treatment capacity is 24,000 m³/day. Part of TWW is sent to the olive crops of El Hajeb, as part of a proposed wastewater use in agriculture. Already the wastewater is used to irrigate olive trees and intercrops such as cotton, oats and sorghum silage (Charfi et al., 1999). The aim of the present work was to determine the impact of the irrigation utilizing wastewater on the quality of the oil. The oils analysed were extracted from olives hand-picked directly from the tree and from olives that have fallen under the trees. Moreover, a study on the olive storage has been made in order to evaluate in which way the collection of the fruit could influence the quality of the oil.     

基于虚拟仪器的植物电信号的测量系统研究

植物电信号是一种相当复杂的微弱信号。根据研究表明．它的幅度在几个pV到几十个mV之间。根据植物电信号的特点，采用虚拟仪器-Lab VIEW技术，开发了一套植物电信号高速采集与处理系统。该系统采用自适应滤波器，利用LMS算法．通过MATLAB编程完成。实验证明，该系统具有自动化程度高、测试灵活、信号采集准确可靠、数据处理能力强等特点。     

机电安装工程施工阶段的人因失误及其控制

文章分析各种诱发人因失误的因素,探明原因,找到根源,才能在实施机电安装之前制定出有效控制人因失误的方案和措施,保障施工的质量和施工安全,减少企业因为人因失误带来的损失,提高企业的经济效益。