检索结果-南通市图书馆

Using an Anion Exchange Membrane to Predict Soil Available N and S Supplies and the Impact of N and S Fertilization on Canola and Wheat Growth

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2007年第1期17卷 77-83页

作者： j.j.schoenau Department of Soil Science University of SaskatchewanSaskatoonS7N 5A8(Canada)

A growth chamber study was conducted to determine the relationships between the supply of soil available nitrogen (N) and sulfur (S) and canola (Brassica napus) and wheat (Triticum aestivum L. 'Biggar') N and S uptake and yield in three Western Canadian soils. The suitability of one-hour burial with an anion exchange membrane (AEM) was assessed for its utility as a quick test of the available N:S balance in the soil. Canola and wheat were grown on a Luvisolic soil low in available S and on Brown and Black Chernozemic soils low in both available N and S, with different rates and combinations of N and S fertilizers applied. AEM burial was used to assess soil available nitrate and sulfate supply rates after fertilization. Dry matter yield and N and S concentrations in plant tissues were determined after 6 weeks of growth. The soil available N:S ratio determined by AEM burial closely reflected the relative supplies of available N and S as revealed in the N:S ratios of plant tissue dry matter. The highest yields were achieved where the available N:S ratio in soil and plant tissue ranged from 5 to 13. Thus, a one-hour burial of an AEM probe in the field may be a useful tool to quickly test if a balanced N and S supply is present in the soil for optimum crop yield.

关键词： anion exchange membrane canola N S wheat

Use　of　Cation　Exchange　Membrane　in　Soil　Potassium　Release　and　Wheat　Response　to　Potassinm

在线全文

学校读者我要写书评

暂无评论

Pedosphere 1995年第3期5卷 203-204页

作者： LIGUI－BAO j.j.schoenau 等 SoilandFertilizerInstitute HenanAcademyofAgriculturalSciencesZhengzouHenan450002China SoilSciences

A pot experiment was conducted in the growth chamber on Saskatchewan soils with dfferent texture todeterniine the K release status and wheat K demand. The relationship between K uptake and soil availableK extracted by cation exchange membrane (CEM-K) and the effect of K fertilizer on wheat growth and soilavailable K was also evaluated. Theatments of 0, 60 and 120 mg K/kg were applied to sandy, low and highK loamy and clay soils. The highest yields were achieved with the application of 120 mg K/kg in sandysoil and 60 mg K/kg in other soils. On the whole, the clay soil contributed K more than other soils fromslowly available fraction. Regression revealed a linear relationship between the soil available K extractedby NH_4OAc(Ka) and CEM-K in suspensions (r=0.93). Results also showed that CEM-K in burial and insuspensions were different not only in the amount but also in correlation with Ka or K uptake.

关键词： cation exchange membrane potassium wheat

在线全文

学校读者我要写书评

暂无评论

氮硫对小麦产量及养分吸收的影响

吉林农业科学 1997年第1期22卷 68-71页

作者：吴巍 j.j.schoenau 钱佩源 K.j.Grear 吉林省农科院土肥所公主岭136100 加拿大Saskatchewan大学土壤科学系

盆栽试验结果表明，在低硫和低氮土壤上，单独施用氮和硫，对小麦的干物质产量没有影响，配合施用显著地增加于物质产量，也显著提高植株氮硫含量和吸收量。获得小麦最大干物质产量的氮硫适宜用量分别为200μg/g和20~40μg/g，再增加用... 详细信息

盆栽试验结果表明，在低硫和低氮土壤上，单独施用氮和硫，对小麦的干物质产量没有影响，配合施用显著地增加于物质产量，也显著提高植株氮硫含量和吸收量。获得小麦最大干物质产量的氮硫适宜用量分别为200μg/g和20~40μg/g，再增加用量导致干物质产量下降。最大干物质产量的土壤适宜N／S为4.0－14.0。

关键词：小麦氮硫干物质产量

离子交换树脂膜法在铵钾交互作用研究上的应用及其与养分生物有效性的关系

在线全文

学校读者我要写书评

暂无评论

中国农学通报 2007年第9期23卷 344-349页

作者：陈小琴周健民 j.j.schoenau P．Y．Qian 王火焰 P．M．Huang 中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室南京210008 萨斯卡彻温大学土壤学系萨斯卡通S7N5A8 中国科学院研究生院北京100039

为探明离子交换树脂膜作为养分提取手段在土壤铵钾交互作用研究上的应用效果,设置了相同培养条件下的树脂膜埋置实验和油菜盆栽试验。结果表明,施钾能减少铵的膜提取量,而施铵对钾的膜提取量影响不显著,这与铵钾同时施用时铵优先固定有... 详细信息

为探明离子交换树脂膜作为养分提取手段在土壤铵钾交互作用研究上的应用效果,设置了相同培养条件下的树脂膜埋置实验和油菜盆栽试验。结果表明,施钾能减少铵的膜提取量,而施铵对钾的膜提取量影响不显著,这与铵钾同时施用时铵优先固定有关。膜提取养分量与植株养分吸收量及干物重之间均达显著或极显著相关,加上树脂膜使用便捷且可以原位提取养分,因而树脂膜可以被当作"根系模拟器"进行养分原位提取和养分交互作用方面的研究。但由于膜与真正的植物根系毕竟不同,故研究中也发现了一些膜提取养分量与植株养分吸收量并不完全一致的情况,这一点在前人的研究中甚少提及,这些情况的发现说明今后的研究中对树脂膜的应用条件还应多加注意,以便对树脂膜更好地利用,达到仅通过树脂膜这种便捷手段不需要通过植物试验就能了解土壤中养分交互作用可能对养分植物有效性的影响的目的。

关键词：铵钾土壤离子交换树脂膜油菜

Error field penetration in j-TEXT tokamak based on two-fluid drift-MHD model

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第4期33卷 545-551页

作者：王文徐涛张仪 the j-TEXT team State Key Laboratory of Advanced Electromagnetic Technology International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma PhysicsSchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

An externally generated resonant magnetic perturbation can induce complex non-ideal MHD responses in their resonant *** have studied the plasma responses using Fitzpatrick's improved two-fluid model and program *** calculated the error field penetration threshold for *** addition,we find that the island width increases slightly as the error field amplitude increases when the error field amplitude is below the critical penetration ***,the island width suddenly jumps to a large value because the shielding effect of the plasma against the error field disappears after the *** scanning the natural mode frequency,we find that the shielding effect of the plasma decreases as the natural mode frequency ***,we obtain the m/n=2/1 penetration threshold scaling on density and temperature.

关键词： plasma responses drift-MHD model error field penetration

Storing Freshwater Versus Storing Electricity in Power Systems with High Freshwater Electric Demand

在线全文

学校读者我要写书评

暂无评论

journal of Modern Power Systems and Clean Energy 2024年第2期12卷 323-333页

作者： Mubarak j.Al-Mubarak Antonio j.Conejo Department of Electrical and Computer Engineering The Ohio State UniversityColumbusOHUSA Department of Electrical Engineering Kuwait UniversityP.O.Box 5969Safat 13060Kuwait Department of Integrated Systems Engineering and the Department of Electrical and Computer Engineering The Ohio State UniversityColumbusOH 43210USA IEEE

We consider a power system whose electric demand pertaining to freshwater production is high(high freshwater electric demand),as in the Middle East,and investigate the tradeoff of storing freshwater in tanks versus storing electricity in batteries at the day-ahead operation *** storing freshwater and storing electricity increase the actual electric demand at valley hours and decrease it at peak hours,which is generally beneficial in term of cost and ***,to what extent?We analyze this question considering three power systems with different generation-mix configurations,i.e.,a thermal-dominated mix,a renewable-dominated one,and a fully renewable *** generation-mix configurations are inspired by how power systems may evolve in different countries in the Middle *** production uncertainty is compactly modeled using chance *** draw conclusions on how both storage facilities(freshwater and electricity)complement each other to render an optimal operation of the power system.

关键词： Power system operation freshwater production and transportation coordination day-ahead scheduling

Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 8-10页

作者： David j.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

关键词：

Global weirding at mass extinction horizons

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 10-12页

作者： Gregory j.Retallack Department of Earth Sciences University of Oregon

A strong motivation for studying mass extinctions is understanding how current climatic and biodiversity crises will affect creatures living on land such as ourselves. Perhaps the question is: how bad can it get? In that case, terrestrial Permian-Triassic mass extinctions are an irresistible worst-case scenario [1].

关键词：

Decoding the genetic program of micronucleus formation: linking chromosomal instability to human disease

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Signal Transduction and Targeted Therapy 2024年第7期9卷 2840-2842页

作者： jörg Fahrer Division of Food Chemistry and Toxicology Department of ChemistryRPTU Kaiserslautern-Landau67663 KaiserslauternGermany

A recent study by Adams and colleagues published in Nature unveiled more than one hundred genes that are involved in micronucleus formation,1 which is a biomarker for genomic instability and associated with aging,cancer,and other disorders.2 As an outstanding achievement,the authors identified DSCC1(DNA Replication And Sister Chromatid Cohesion 1)as a critical gene protecting against early developmental defects,genomic instability,reduced proliferative capacity,cohesinopathy-related phenotypes,and tumor development in vivo.

关键词： chromosomal linking Replication