阴离子对可变电荷土壤吸附铜离子的影响机理   总被引：1，自引：0，他引：1  

邹献中  姜军  赵安珍  季国亮 《土壤学报》2012,49(2):311-318

根据NO-3、Cl-和SO24-对可变电荷土壤和恒电荷土壤吸附Cu2+的影响的比较,探讨了阴离子对可变电荷土壤吸附Cu2+的影响机理。结果表明,当3种阴离子的浓度相同时,在SO24-体系中铁质砖红壤对Cu2+的吸附率较在NO3-和Cl-体系中大得多,而在浓度相同的3种阴离子体系中,黄棕壤对Cu2+的吸附率相差不大。在离子强度相近的NaCl体系中,砖红壤对Cu2+的吸附率相近。在3种阴离子体系中,随着pH升高,砖红壤对Cu2+的吸附率均增大;但在NO-3体系和Cl-体系中Cu2+的吸附率相近;而在SO24-体系中Cu2+的吸附率最大。随着Na2SO4浓度的增大,铁质砖红壤和砖红壤对Cu2+的吸附率减小。但在0.005 mol L-1和0.05 mol L-1Na2SO4体系中,Cu2+的吸附率大于在不含Na2SO4的体系中者。而在0.5 mol L-1Na2SO4体系中,Cu2+吸附率小于在不含Na2SO4体系中者。在3种浓度的Na2SO4体系中,黄棕壤对Cu2+的吸附率均小于在不含Na2SO4体系中者。总之,阴离子可通过离子强度、专性吸附和形成离子对影响土壤对Cu2+的吸附。在可变电荷土壤中,阴离子对Cu2+吸附的影响机理较在恒电荷土壤中复杂得多。  相似文献   

Human milk fat globules from different stages of lactation: a lipid composition analysis and microstructure characterization     

Zou XQ  Guo Z  Huang JH  Jin QZ  Cheong LZ  Wang XG  Xu XB 《Journal of agricultural and food chemistry》2012,60(29):7158-7167

The physicochemical properties of human milk fat globules (MFG) at different lactation stages from Danish mothers and the microstructure changes of MFG membrane (MFGM) at varied temperatures were investigated, and the relationship between chemical composition and the microstructure of MFGM was elucidated. The fat content in MFG was found to be significantly increased as lactation progressed, and colostrum MFG had the largest mean diameter of 5.75 ± 0.81 μm and the lowest ζ potential of -5.60 ± 0.12 mV. Chemical composition analyses of MFG revealed the following: (i) Colostrum milk fat constituted higher content in PUFAs (ω-6, and long-chain ω-6 and ω-3) than transitional and mature milk fats, with the corresponding lower content of SFA in its sn-2 position. (ii) The content of polar lipids among total lipids varied during lactation course (maximized at transitional stage); however, in terms of subclasses of polar lipids, no significant change of the relative content of sphingomyelin was observed, while the content of phosphatidycholine in mature milk was higher than that in colostrum and transitional milk. (iii) Inspection of fatty acid composition in phospholipids from different lactation milk revealed no remarkable and regular changes could be generalized; and no obvious difference of the morphologies of MFGM at different lactation stages can be visualized. An investigation of the microstructure change of MFGM vs temperature demonstrated that the segregated domains became larger as temperature decreased to 4 °C, while it became smaller when increased to 37 °C. This phenomenon indicated that, in addition to sphingimyelin and cholesterol, phospholipids might also contribute to increasing the segregated domains at lower temperature, while, at elevated temperature, these domains could be diminished, most likely due to a restructuring or distributing of sphingimyelin and cholesterol.  相似文献   

库区生态公益林改造对林地水土流失的影响研究倡     

邹显花  马祥庆  吴鹏飞  李建民  廖国华  林福星 《亚热带水土保持》2012,(2):5-10,13

以福建永安安砂库区生态公益林为研究对象,通过设置径流小区,分别在坡度25°和32°的林地中,设计4种不同间伐强度处理(不间伐、20%、40%、60%间伐强度),研究不同间伐强度及间伐后补植枫香两种改造措施对库区生态公益林林地水土流失的影响.结果表明:40%及60%间伐强度林地的水土流失量大于不间伐处理,中高强度间伐后套种枫香的改造措施同样加大了库区生态公益林地的水土流失,但小于间伐措施的流失量,且水土流失量随着坡度的增加而加大.而在适当的低强度间伐(20%间伐强度)条件下,实施两种改造措施之后的库区生态公益林的水土流失量与不间伐处理之间差异并不明显.因此,选择在低坡度(25°)进行适当的低强度(20%间伐强度)间伐并套种枫香等阔叶树种,可达到在兼顾生态效益的同时,科学合理地利用生态公益林的林木和景观资源的目的  相似文献   

基于遥感信息与作物模型集合卡尔曼滤波同化的区域冬小麦产量预测   总被引：21，自引：13，他引：8  

黄健熙  武思杰  刘兴权  马冠南  马鸿元  吴文斌  邹金秋 《农业工程学报》2012,28(4):142-148

区域作物产量预测是国家粮食安全评估的重要内容。遥感虽能获取大面积地表信息,却难以反映作物生长发育的内在过程。作物生长模型已经在单点尺度能成功模拟作物的生长发育过程,但是区域尺度作物关键参数的获取仍很困难。遥感信息与作物模型结合的数据同化已经成为区域产量预测的最有效途径。该文选择河北省衡水地区冬小麦为研究对象,在WOFOST模型标定与区域化的基础上,利用WOFOST模型描述冬小麦生育期内叶面积指数(LAI)变化规律。针对MODIS数据的混合像元造成反演的LAI产品偏低的系统误差,利用实测LAI样本点融合MODIS-LAI趋势信息修正MODIS-LAI数据产品。采用集合卡尔曼(EnKF)算法同化冬小麦返青到抽穗期的MODIS-LAI与WOFOST模拟的LAI以获得时间序列最优的LAI,并以此重新驱动WOFOST模型估算区域冬小麦产量。结果表明,EnKF同化后的冬小麦产量比未同化的产量预测精度有显著提高,与县平均统计产量相比,在潜在模式下,决定系数由0.13提高到0.38,均方根误差由2480下降到880kg/hm2。研究表明,遥感信息与作物模型的EnKF同化是1种有效的作物产量预测方法,并在区域尺度应用上具有广阔的应用潜力。该研究可为区域尺度的作物估产提供参考。  相似文献   

龙须草茎秆往复式切割试验研究   总被引：9，自引：5，他引：4  

罗海峰  汤楚宙  邹冬生  李顺春  吴万刚  邹运梅 《农业工程学报》2012,28(2):13-17

为解决现有往复式切割器收割龙须草的问题,拟对龙须草茎秆进行切割间隙、切割速度、切割刀片组合形式、切割茎秆部位、切割茎秆数量等因素进行了单因素试验,在单因素试验的基础上选取了正交试验的因素水平,完成了茎秆最大剪切力的正交试验,实验结果表明切割间隙和切割刀片组合形式对剪切力影响较大,切割速度对剪切力影响相对较小。最后通过选取斜齿刀-斜光刀组合模式与斜光刀-斜光刀传统刀片组合进行田间试验对比,结果表明斜齿刀-斜光刀组合的切断率提高了23%,刀片缠草率降低了94%,极大地提高了龙须草切割作业质量和作业效率。研究结果表明斜齿刀-斜光刀组合刀片用于龙须草收割是可行的。  相似文献   

曝气生物滤池对玉米青贮渗出液处理效果     

邹海明  王艳  李飞跃  李永刚 《农业工程学报》2012,28(16):203-207

为了考察曝气生物滤池(biological aerated filter,BAF)处理玉米青贮渗出液的效果及其影响因素,重点考察了水力负荷、气水比、有机负荷和滤床高度。结果表明:水力负荷从0.5m3/(m2.h)升高到3.0m3/(m2.h)过程中,化学需氧量(COD)和NH3-N的去除率先升高后降低,当水力负荷1.5m3/(m2.h)时COD和NH3-N的去除率分别达到最大为83.5%、74.9%;增加气水比使得系统中溶解氧充足,可明显提高COD和NH3-N去除率,当气水比为3.5:1时COD和NH3-N的去除率分别达到最大为87.5%、75.2%;低有机负荷不利于COD和NH3-N的去除,当有机负荷为COD2.4kg/(m3.d)时,COD和NH3-N去除率最低分别仅为49.6%、58.5%,有机负荷为COD4.8kg/(m3.d)时去除率最高分别可达80.9%和75.9%,但过高的有机负荷反而对NH3-N去除不利,当有机负荷为COD7.2kg/(m3.d)时,NH3-N去除率降低为61.7%;滤床高度对硝化反应去除NH3-N影响较大,NH3-N生物硝化反应去除行为主要发生在0.6～1.0m区域。试验表明采用BAF系统处理玉米青贮渗出液是可行的,也为类似性质废水处理和改善农村水环境质量提供有益的参考。  相似文献   

胶州市胶北镇10个村庄土地集约利用水平评价   总被引：3，自引：1，他引：2  

刘洁  王瑷玲  姜曙千  邹县委  孙娟 《农业工程学报》2012,28(25):244-249

村庄土地集约利用评价是村庄整治规划的重要组成部分。该研究在明确村庄土地集约利用内涵基础上,以胶州市胶北镇10个村庄为例,构建了村庄土地集约利用评价指标体系,采用多因素综合评价法评价了村庄土地集约利用状况。评价结果表明,村庄土地集约利用水平总体较低,其中3个村庄低度利用,7个村庄中度利用,无村庄过度利用或集约利用。在结果分析基础上,提出了建设新型农村社区、合理利用空闲地和闲置宅基地、提高村庄生活便利度和改善生态环境等建议。该研究可为开展村庄整治提供参考。  相似文献   

果实果皮研究进展     

孙浩  曾杰  欧立军  邹学校 《中国农学通报》2021,37(6):49-53

果皮是果蔬最直观的品质性状,也是衡量果实商品价值的重要指标之一。笔者从生理生化和分子机制角度叙述了果皮颜色变化的原理。简述了果皮色素抗癌、抗氧化等保健功能和目前常见的3项天然色素提取工艺。总结了果皮褐变机理和生长调节剂对果皮褐变的调控效果。今后可将新型复合包装材料与褐变抑制剂相结合的手段用于果实采后贮藏保鲜。目前调控黄瓜果皮颜色的基因如CsaARC5等5种基因以及辣椒颜色相关基因Ccs已被克隆。深入探究果皮颜色调控机制对今后运用基因工程进行果皮颜色改良意义重大。  相似文献   

Metabolites with Anti-Inflammatory Activity from the Mangrove Endophytic Fungus Diaporthe sp. QYM12     

Yan Chen  Ge Zou  Wencong Yang  Yingying Zhao  Qi Tan  Lin Chen  Jinmei Wang  Changyang Ma  Wenyi Kang  Zhigang She 《Marine drugs》2021,19(2)

One new diterpenoid, diaporpenoid A (1), two new sesquiterpenoids, diaporpenoids B–C (2,3) and three new α-pyrone derivatives, diaporpyrones A–C (4–6) were isolated from an MeOH extract obtained from cultures of the mangrove endophytic fungus Diaporthe sp. QYM12. Their structures were elucidated by extensive analysis of spectroscopic data. The absolute configurations were determined by electronic circular dichroism (ECD) calculations and a comparison of the specific rotation. Compound 1 had an unusual 5/10/5-fused tricyclic ring system. Compounds 1 and 4 showed potent anti-inflammatory activities by inhibiting the production of nitric oxide (NO) in lipopolysaccharide (LPS)-induced RAW264.7 cells with IC₅₀ values of 21.5 and 12.5 μM, respectively.  相似文献   

Total Synthesis and Anti-Inflammatory Bioactivity of (−)-Majusculoic Acid and Its Derivatives     

Hong-Xiu Xiao  Qing-Xiang Yan  Zhi-Hui He  Zheng-Biao Zou  Qing-Qing Le  Ting-Ting Chen  Bing Cai  Xian-Wen Yang  Su-Lan Luo 《Marine drugs》2021,19(6)

The first total synthesis of marine natural product, (−)-majusculoic acid (1) and its seven analogs (9–15), was accomplished in three to ten steps with a yield of 3% to 28%. The strategy featured the application of the conformational controlled establishment of the trans-cyclopropane and stereochemical controlled bromo-olefination or olefination by Horner–Wadsworth–Emmons (HWE) reaction. The potential anti-inflammatory activity of the eight compounds (1 and 9–15) was evaluated by determining the nitric oxide (NO) production in the lipopolysaccharide (LPS)-induced mouse macrophages RAW264.7. (−)-Majusculoic acid (1), methyl majusculoate (9), and (1R,2R)-2-((3E,5Z)-6-bromonona-3,5-dien-1-yl)cyclopropane-1-carboxylic acid (12) showed significant effect with inhibition rates of 33.68%, 35.75%, and 43.01%, respectively. Moreover, they did not show cytotoxicity against RAW264.7 cells, indicating that they might be potential anti-inflammatory agents.  相似文献