二种灌溉方式下磷在土壤中空间运移的研究

采用Surfer软件分析的方法,研究棉花膜下滴灌和膜下软管二种灌溉方式下磷在土壤中的分布特点以及棉花生长状况。结果表明,在土壤中下渗(0～30cm),膜下滴灌磷的浓度与膜下软管磷的浓度分别为25～30 mg/kg和22～26 mg/kg;膜下滴灌条件下磷在土壤中侧渗范围为0～10cm,磷的浓度为9～25mg/kg;膜下软管条件下磷在土壤中侧渗范围为0～20cm,磷的浓度为12～26mg/kg;棉花膜下滴灌平均单产(籽棉)比棉花膜下软管灌平均单产(籽棉)多127.5kg/666.7m2。膜下滴灌磷在土壤中分布集中,浓度相对较高,分布均匀,利于棉花根系的吸收,提高了磷的利用率;而膜下软管灌磷在土壤中分布分散,浓度较低,均匀性差,磷利用率较低。因此,棉花膜下滴灌磷的效果比棉花膜下软管磷的效果好,同时膜下滴灌磷通过随水施入土壤中可以满足棉花整个生育期需要。     

鲁北盐渍土区棉花微咸水滴灌技术研究

对春棉利用含盐量3.8g/L浅层地下微咸水及1.2g/L深井水进行膜下滴灌、无膜滴灌、覆膜畦灌及无灌溉田间对比试验,结果表明;1.2g/L膜下滴灌皮棉产量最高,其次为3.8g/L膜下滴灌,相差22％;两种灌溉水的无膜滴灌及覆膜畦灌4个处理的皮棉产量基本持平,无灌溉产量最低。3.8g/L微碱水灌溉条件下,膜下滴灌比覆膜畦灌增产38.6%,比无膜滴灌增产40.1%,比无灌溉增产92.5%。滴灌比覆膜畦灌省水60％左右,滴头的湿润半径能达到20cm左右,湿润深度能达到60cm左右;试验期间0－60cm土层土壤盐分含量低于0.2%,不会对棉花生长产生危害。     

膜下滴灌条件下棉花花铃期冠层内的温光特征分析

设计棉花膜下滴灌与普通沟灌2种灌溉方式。在棉花花铃期对冠层内的温度、光照强度、净辐射和消光系数等进行了同步观测。结果表明。在两种灌溉方式下棉花雹层内的温度、光照强度和净辐射日变化曲线均呈单峰线；花铃期初期和后期膜下滴灌棉花冠层温度、净辐射大于常规灌溉。而光照强度和消光系数均小于常规灌溉。     

不同滴灌施肥方式对盐渍土棉花生长和氮素吸收的影响

探讨不同氮肥滴灌施肥方式对盐渍土壤上棉花生长和氮素吸收的影响,对于膜下滴灌条件下盐渍土的合理利用和水肥管理有重要意义。在膜下滴灌条件下,进行了不同氮肥滴灌施肥方式和土壤盐度对棉花生长和氮素吸收影响的田间试验。试验结果表明：氮肥滴灌施肥方式和土壤盐度显著影响棉花的生物量和产量。氮肥在一次灌溉的前期施用的施肥方式可显著促进棉花生长,尤其可以显著提高结铃数,从而增加棉花的生物量和籽棉产量。棉花的氮素吸收受土壤盐度、施肥方式以及二者交互作用的影响显著。在土壤盐度较低条件下,氮肥在一次灌溉的前期施用的施肥方式可显著提高棉花的氮素吸收总量;而盐度较高时,氮肥在一次灌溉的中间施用的施肥方式则有助于促进棉花的氮素吸收。     

盆栽滴灌棉花土壤耗水变化特征的试验研究

面对近年来新疆棉花膜下滴灌区日益严重的残膜污染及地下滴灌苗期灌水困难的实际,提出将无膜移栽与地下滴灌有机结合的棉花无膜移栽地下滴灌技术,为研究在干旱区采用此技术下棉花的耗水规律,进而验证该技术在新疆的可能性,进行了不同滴灌方式下棉花土壤水分变化盆栽试验,试验设5种处理：覆膜移栽地下滴灌（FT-SDI）、无膜移栽地下滴灌（NFT-SDI）、覆膜直播地下滴灌（FS—SDD、无膜移栽地表滴灌（NFT-DI）、覆膜直播地表滴灌（FS-DI）。结果表明：对于棉花全生育期土壤水分变化而言,NFT—DI处理最大,地下滴灌节水效果明显,FT—SDI处理最小,NFP—SDI处理仅次;移栽地下滴灌棉花整个生育期表层（0～30cm）土壤耗水量,无膜处理高于覆膜处理;苗期无膜移栽地下滴灌的耗水强度相对较大,灌水量也相应加大;在覆膜地下滴灌条件下,苗期移栽处理比直播处理耗水强度较小,耗水量也小,地下滴灌条件下,移栽相对直播更利于棉苗生长发育;无膜移栽地下滴灌棉花的花铃期灌水量小于膜下滴灌,土壤水分变化主要集中在30～80cm,全生育期土壤耗水量略高于覆膜地下滴灌,而均低于地表滴灌。这表明棉花无膜移栽地下滴灌技术既可充分发挥移栽和地下滴灌的优势,在干旱区完全可行并具有较好的应用前景,值得进一步深入研究。     

咸水灌溉对土壤理化性质和棉花产量的影响

水资源短缺是制约区域经济和社会发展的瓶颈,微咸水膜下滴灌是缓解农业用水短缺的有效途径之一。本文通过微咸水和咸水膜下滴灌棉花测坑试验,运用舒卡列夫分类和Piper三线图等方法研究矿化度分别为1、3、6、9、12 g/L水膜下滴灌对土壤含水率、土壤电导率(EC)、土壤八大离子、土壤溶液水化学特征、土壤p H和产量的影响,从而确定棉花适宜的灌水矿化度。结果表明:(1)当矿化度低于6 g/L时,土壤积累的盐分对棉花吸收水分没有严重影响,棉花生理生长适宜的土壤含水率应在10%～20%之间;(2)在不同矿化度水灌溉条件下,0～20 cm土壤处于积盐状态,20～100 cm土层积盐较小,且各处理0～20 cm土壤中SO_4~(2-)、Ca~(2+)、K~++Na~+和Cl~-含量较多;(3)随着灌水矿化度的增大,土壤中的阳离子由Ca~(2+)逐渐向Mg~(2+)和K~+变化,阴离子由SO24-和HCO_3~-逐渐向Cl-变化,水化学类型由SO_4~(2-)·HCO_3~--Ca~(2+)·K+型逐渐向SO_4~(2-)-·Cl~--Ca~(2+)·K+型演化;(4)棉花在蕾期、花铃期和吐絮期土壤pH值随矿化度的增大而增大;棉花产量随灌水矿化度的增加而减小,其中1、3、6 g/L处理下的棉花产量较高。综合各种因素后0～6 g/L是微咸水灌溉棉花适宜的矿化度。     

棉花膜下滴灌水氮耦合的初步研究

采用田间单因素和复因素试验研究了棉花膜下滴灌耗水和氮素养分吸收的规律,并建立棉花膜下滴灌水氮耦合方程。研究结果表明,现蕾前吸收的氮素养分不到总量的5％,盛花到吐絮期吸收养分的比例最大,超过60％,棉花膜下滴灌将大部分氮肥以追肥分配给棉花是符合棉花养分需求的生理规律的。膜下滴灌棉花全生育期耗水量在北疆石河子地区,苗期平均耗水量为44mm,蕾期平均耗水量为113mm,开花．盛铃期平均耗水量为182mm,盛铃期一吐絮期平均耗水量为98mm,总耗水量为437mm,随着灌溉量的增加,棉花耗水量也逐渐增加。建立了棉花水氮耦合回归方程,据此计算最高产量灌溉量为4189．5m3／hm2,最高产量施N量为223．5kg／hm2。采用“空间寻址法”计算最佳水肥耦合组合,发现棉花产量在4560～5040kg／hm2的频率最大,相应的最佳灌溉量、施氮量分别为4125m3／hm2、205．5kg／hm2以及4170m3／hm2、223．5kg／hm2。因此建议施氮量214．5kg／hm2,灌溉量4125m3／hm2为最佳水肥耦合组合。     

新疆典型节水灌溉技术的三级模糊评价模型及分析

为了探明新疆膜上灌、膜下滴灌、自动化膜下滴灌3种典型节水灌溉技术综合效益的差异,本文充分考虑其横向及纵向的影响因素,运用资料收集、大田试验、问卷调查的方式,依据定性与定量相结合的分析原则,选取涵盖经济效益、环境效益、社会效益三方面26个相互独立的敏感性指标,构建了一套层次分析法与模糊综合评价法相结合的三级模糊评价模型。采用该模型评价3种典型节水灌溉技术综合效益的结果表明:膜上灌、膜下滴灌、自动化膜下滴灌的综合效益评价等级分别为差、一般、较好;与膜上灌相比,膜下滴灌与自动化膜下滴灌的突出优势是灌溉水利用系数分别提升28. 8%、38. 7%,分别节约人力35. 7%、62. 3%,节水1 150. 84、1 874. 64 m~3/hm~2,产量提高2 361、2 820. 9 kg/hm~2。因此,该模型能较好地评价新疆典型节水灌溉技术的综合效益,且通过评价结果可得到各灌溉技术的突出优势及不足,新疆未来可持续性节水技术的发展方向是大力发展和普及自动化膜下滴灌技术。     

新疆绿洲棉田盐分及作物生长对灌溉方式的响应

干旱地区的水资源短缺使得膜下滴灌逐渐取代大水漫灌,在新疆及中国北方地区得到大面积推广应用。为研究灌溉方式转变后的土壤盐分动态及对作物生长和产量的影响,于2011年和2012年开展了棉田膜下滴灌和漫灌对比实验。基于6 900个土壤样本的水、盐结果及相关的作物观测数据,结果表明:膜下滴灌下,50cm土壤深度内盐分在出苗期和灌溉期升高约25%,呈现出累积趋势;而漫灌条件下,灌溉期盐分得到充分淋洗,降低明显;滴灌盐分的入渗深度约为50cm,而漫灌则达到150cm以上。作为对土壤水盐分布改变的响应,膜下滴灌根系更为发达,滴灌条件下棉花根系总量是漫灌条件下的1.6倍;膜下滴灌和漫灌的水分利用效率(WUE)分别是0.68kg/m3和0.22kg/m3。膜下滴灌实现了良好的经济和环境效益,但在长期应用条件下需注意防治淋洗水量不足引发的盐碱化风险。     

棉花膜下滴灌灌溉制度丰产试验

本试验对棉花膜下滴灌灌溉制度及其各因素的特点进行了分析。膜下滴灌技术采用局部灌水，田间地面蒸发量小，可控性强，减少了深层渗漏，提高了田间水的利用率。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of