An electroosmotic pump for packed capillary liquid chromatography

An electroosmotic pump (EOP) capable of generating pressure above 3 MPa and mul/min flow rate with reverse phase mobile phases of HPLC was constructed and evaluated. The pump consisted of three parallel connected fused silica capillary columns (25 cm x 320 mum I.D.) packed with 2 mum silica materials, hollow electrodes, a high voltage DC power supply, and. a liquid pressure transducer. The EOP was applied in a capillary liquid chromatographic system for mobile phase delivery instead of a mechanical pump. Standard samples containing thiourea, naphthalene, anthracene, phenanthrene and acetonitrile were separated on a 15 cm x 320 mum I.D. 5 mum Chromasil C-18 packed capillary column with acetonitrile/water as mobile phase. (C) 2003 Elsevier Science B.V. All rights reserved.

沉积物中典型氧化物矿物吸附的镉对芦苇的生物有效性研究

选用沉积物中5种典型氧化物矿物:针铁矿、磁铁矿、三水铝石、氧化铝、二氧化锰,以水培法和单一矿物吸附Cd为培养介质,以芦苇为受试植物,研究环境中不同化学形态Cd(即吸附在不同矿物表面)的生物有效性差别.经过45 d的培养,发现矿物吸附的Cd被芦苇吸收富集,不同形态Cd的富集强度不同,根组织富集量72.70~320.44 mg.kg-1,并遵循以下规律:Al(OH)3>Al2O3>Fe3O4>MnO2>FeOOH.Cd的富集特征反映了不同矿物吸附Cd能力和稳定性的差异,通过采用3种低分子量有机酸对Cd的解吸,评价了这几种矿物对镉的吸附强度.结果表明,Cd的解吸量遵循如下规律,乙酸、苹果酸:Al(OH)3>Fe3O4>Al2O3>FeOOH>MnO2;柠檬酸:Al(OH)3>Al2O3>Fe3O4>FeOOH>MnO2,这与芦苇对各种矿物吸附镉的富集程度顺序基本一致.Cd的化学形态是影响其生物有效性的重要因素.

Reversed capillary electrochromatography: Investigation of peak symmetry for eluting curves of solutes

The transport processes of components in capillary electrochromatographic column was investigated based on the basic model of relaxation theory. A principal transport equation of chromatographic relaxation theory was established and mathematical expressions for eluting curves were obtained under the situations of both capillary electrophoresis and chromatography. Characteristics of peak symmetry and its effecting factors are discussed. Tailing peaks, symmetrical peaks and fronting peaks would be observed simultaneously, which was further proved with reversed capillary electrochromatographic experiments.

过量Mg~(2+)对农作物种子萌发特性的影响

[目的]揭示过量Mg2+对玉米和大豆萌发特性的影响。[方法]设0、40、80、120、160、200、240、280、320、360、400 mmol/L11个Mg2+浓度处理,研究不同处理对玉米和大豆发芽势、发芽率、鲜重、干重、根长、株高、茎粗等指标的影响。[结果]随着Mg2+浓度的升高,玉米的发芽被延缓,而大豆发芽率降低明显,达到0.05水平的显著性差异。随着Mg2+浓度升高,玉米和大豆的鲜重和干重降低,但均表现出一定的适应性。玉米和大豆幼根和幼苗生长受Mg2+抑制明显,普遍表现出萎缩、发育不良现象。[结论]过量Mg2+胁迫对不同农作物的发芽势、发芽率影响不同,对农作物的根、茎器官生长毒害作用明显。

过量Mg~(2+)对农作物种子萌发特性的影响(英文)

[Objective] The research aimed to reveal the effects of excessive Mg2+ on the germination characteristics of maize and soybean. [Method] Eleven concentration gradients of Mg2+ including 0,40,80,120,160,200,240,280,320,360 and 400 mmol/L were set up to study the effects of different treatments on such indices as the germination potential,germination rate,fresh weight,dry weight,root length,plant height and stem diameter of maize and soybean. [Result] With the increasing of Mg2+ concentration,the germination of maize delayed and the germination rate of soybean obviously decreased,reaching the significant difference at 0.05 level. When Mg2+ concentration increased,the fresh weight and dry weight of maize and soybean decreased,but maize and soybean showed some adaptability. The growth of radicles and seedlings in maize and soybean were obviously inhibited by Mg2+,and atrophy and dysplasia phenomena appeared. [Conclusion] Excessive Mg2+ stress has different effects on the germination potential and germination rate of different crops and has obvious poisoning effects on the root and stem growth of crops.

旱地春小麦集雨补灌增产机制初探

为查明集雨补灌对不同种植模式小麦的增产机理 ,于 1 998年在甘肃中部旱农区进行了田间试验。结果表明 :少量灌水使沟播春小麦出苗率提高 ,小穗数及穗粒数增加 ;在植株生长的需水关键期补灌 ,小麦叶面积增大 ,叶绿素含量提高 ,地上部干物质及籽粒干物质积累量增加 ,有效小穗数及穗粒数增多 ,穗粒重及千粒重增大 ,最终经济产量和生物产量提高。籽粒平均灌浆速率和最大灌浆速率提高是旱田补灌作物增产的主要机制。

A study of fucoidan from the brown seaweed Chorda filum

Fucoidan fractions from the brown seaweed Chorda filum were studied using solvolytic desulfation.Methylation analysis and NMR spectroscopy were applied for native and desulfated polysaccharides.Homefucan sulfate from C.filum was shown to contain poly-a-(1-3)-fucopyranoside backbone with a high degree of branching,mainly of a-(1-2)-linked single units.Some fucopyranose residues are sulfated at O-4(mainly) and O-2 positions.Some a-(1-3)-linked fucose residues were shown by NMR to be 2-O-acetylated.The 1H and 13C NMR spectra of desulfated,deaceylated fucan were complerely assigned.THe spectral data obtained correspond to a quasiregular polysaccharide structure with a branched hexasaccharide repeating unit.Other fucoidan frations from C.filum have more complex carbohydrate composition and give rather complex methvlation patterns.

陕北山地红枣集雨微灌技术集成与示范

陕北山地红枣集雨微灌技术综合集成了坡地降雨径流调控技术、山地红枣矮化密植栽培技术及修剪技术,在对微灌技术进行创新的基础上,形成了黄土高原山地红枣微灌技术体系,并在黄土高原丘陵沟壑区第一附区——陕西省榆林市米脂县创建了技术体系应用实体样板,该样板地红枣平均产量达到19 800 kg/hm2,较无灌溉条件(产量4 500~6 000 kg/hm2)增产2~3倍,较管灌条件(产量一般为12 000~15 000 kg/hm2)增产30%~60%,且节水36%以上。在单项技术研究方面,利用Penman-Monteith公式确定了红枣生育期理论耗水量(438.8mm);通过不同灌水量处理的田间试验,初步确定出合理的灌水量区间为396~1 320 m3/hm2;提出了坡地低压滴灌工程新的设计理论,即微地形影响下的均匀度计算方法、滴头设计工作压力取值理论及毛管设计新方法;在此基础上,提出了坡上部采用三项配套技术+低压滴灌、坡下部采用三项配套技术+涌泉根灌+雾喷的工程模式。

潜流人工湿地不同基质除磷研究

目的考察实验材料的磷吸附容量,优选1~2种除磷性能良好的湿地基质材料.方法分析材料的理化特性,通过吸附等温曲线实验和吸附动力学实验比较材料的除磷容量,并对除磷容量与其本身的理化特性进行相关性比较.结果当接触液初始质量浓度为320 mg/L时,试验材料对磷的吸附量为石灰石>硅灰石>沸石>陶粒>沙子;在pH为6.60~7.69时,决定基质材料磷吸附容量最关键的因素是材料钙和铝的含量.接触液磷质量浓度不同对不同材料的吸磷量影响显著.不同材料基质的磷吸附平衡时间和吸附速率都存在着差异,对磷的吸附速率与材料对磷的吸附容量没有直接的相关性.结论石灰石和硅灰石是较好的潜流人工湿地除磷基质,可以与普通沙子混合级配,陶粒如果在制造过程中添加一些钙化合物也将成为一种合适的人工湿地基质材料.

生物有机肥对小油菜生长及品质的影响

在小油菜上进行施用生物有机肥、有机无机配合施肥、三元肥的田间对比试验。结果表明,单施生物有机肥比单施无机三元肥的小油菜中硝酸盐和亚硝酸盐含量分别降低36.17%和21.77%;种植后土壤中有机质比单施无机三元肥提高11.12%。油菜生产中施用生物有机肥可以提高作物品质,提高土壤有机质含量,培肥地力,与三元肥配合施用不会造成明显减产。