Influence of surface charge on viscosity behavior of cellulose microcrystal suspension

Microcrystalline cellulose with minimal surface charge was prepared from softwood kraft pulp via hydrolysis by 4N hydrochloric acid instead of sulfuric acid. To this material, sulfate ester groups as surface charge were introduced by treating with 55% (w/w) sulfuric acid. A treatment at 60°C for 2h gave nearly the same level of surface charge as that of the H₂SO₄ -hydrolyzed microcrystal. The number of sulfate groups were controlled by changing the H₂SO₄ treatment conditions. Although the microscopic size and shape of the microcrystalline particles were the same irrespective of the preparation method, the introduction of surface charge drastically reduced the viscosity and removed its time dependence. These changes in viscosity behavior are considered to result from charge-induced dispersion of loose aggregates existing in the initial charge-free microcrystals prepared by HCl hydrolysis.Part of this report was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

硫酸锰浸种对马铃薯产量和品质的影响

田间条件下,通过不同浓度硫酸锰浸种,研究了锰对马铃薯生长发育、产量及品质的影响。结果表明,低浓度硫酸锰浸种能够促进马铃薯植株生长发育,并增加产量、提升品质;但锰素过多又会对其产生不利影响。其中,用0.05%硫酸锰浸种,植株生长旺盛,产量增加显著;0.15%硫酸锰浸种,块茎品质最佳。结果提示,用0.05%～0.15%的硫酸锰浸种能有效提高马铃薯产量、改善品质。     

硫磺、硫酸锌、硼砂施用量与玉米淀粉含量关系的研究

采用二次回归通用旋转组合试验设计,分析硫磺、硫酸锌、硼砂不同施用量对高淀粉玉米淀粉含量的影响。结果表明：硫磺、硫酸锌与玉米淀粉含量的关系符合二次曲线,硼砂与淀粉含量为正的线性关系;单独施用时,硫磺和硫酸锌降低淀粉含量,硼砂增加淀粉含量;硫磺与硫酸锌存在正向互作,与硼砂存在负向互作;硫酸锌与硼砂不存在互作。淀粉含量高于76.39%的施肥方案是硫磺、硫酸锌、硼砂用量分别为6.39～31.56、8.2～32.0、22.4～28.5 kg/hm2。     

Effects of an Aluminum Sulfate and Ferric Chloride Blend on Poultry Litter Characteristics in Vitro

Previous studies have applied various concentrations of aluminum sulfate and ferric chloride separately to poultry litter to reduce environmental pollution and increase chicken productivity. In the present study, we investigated the effect of using a blend of these 2 chemicals under 5 different treatments: control (no addition), 50 + 50, 25 + 50, 50 + 25, and 25 + 25 g/kg of litter, which consisted of fresh chicken manure (1 kg) and sawdust (4 kg) thoroughly mixed in a 70 × 47 × 43 cm box. NH₃ and CO₂ volatilizations, pH, electrical conductivity (EC) and moisture content of the poultry litter were assessed weekly up to 6 wk and in the case of total and water-soluble nutrients they were assessed after 1 and 42 d. The control treatment had higher NH₃ and CO₂ volatilizations than the treated litter throughout the experiment. EC and pH showed an inverse relationship, whereby the control treatment had high pH and low EC values and the treated litter had low pH and high EC values. After 42 d, nitrogen levels were significantly reduced in the control treatment, whereas the 50 + 50 g/kg treatment had the highest content. Conversely, water-soluble phosphorus levels were much lower in the treated poultry litter after 1 and 42 d. A higher ferric chloride concentration (25 + 50 g/kg) in the blend was more effective than a higher aluminum sulfate concentration (50 + 25 g/kg). These findings demonstrate that a combination of aluminum sulfate and ferric chloride may be a useful amendment for reducing NH₃ and CO₂ volatilizations, pH, and moisture content of poultry litter, which will help in improving poultry productivity, pollution control, and poultry litter fertilizer usage.     

不同施肥结构对番茄营养品质和硝酸盐含量的影响

研究了不同施肥结构对番茄营养品质和硝酸盐含量的影响。试验结果表明,8个处理中,有机肥 硫酸铵 过磷酸钙 硫酸钾处理的维生素C、可溶性糖含量,糖酸比最高;硝酸盐含量最低,为167mg/kg;硝酸还原酶活性最高。因此,有机肥 硫酸铵 过磷酸钙 硫酸钾处理是番茄栽培的最佳施肥结构。     

Differences in aluminium tolerance of ryegrass and white clover plants grown from seed or propagated vegetatively

The effect of aluminium (Al) on the relative yield of plants grown from seeds of ryegrass (Lolium perenne L.) or white clover (Trifolium repens L.) and either tillers (ryegrass) or stolon tip cuttings (white clover) were investigated using a low ionic strength (2.7 x 10^‐3 M) solution culture technique. In ryegrass, plants grown from tillers had higher relative yields than plants grown from seedlings in the tops when solution Al concentrations were greater than 16 μM and in the roots when solution Al concentrations were greater than 7 μM. In white clover, relative yields in the tops and roots plants were higher in plants grown from stolon tip cuttings than from seedlings when solution Al concentrations were greater than 10 μM. There were no significant cultivar effects. The results indicate that plants used in Al‐tolerance experiments can be grown from seed or vegetatively propagated, provided solution Al rates are adjusted to reflect differences in Al tolerance.     

SOIL NITROGEN MINERALIZATION UNDER NORTHERN HARDWOOD FORESTS ALONG A SULFATE AND NITRATE DEPOSITION GRADIENT IN THE GREAT LAKES REGION

INTRODUCTIoNChangesinsoilNmineralizationratescouIdbeanearlywarningofsoilNavaila-bilityoreventualforestdeclinesinceNisoftenan.importantnutrientforgrowth(Keeneyl98O;Leaetal.l982;Vitouseketal-l982).Nitrogenmineralizationinvolvestwodistinctprocessesfammonification,inwhichNH:isformedfromorganiccom-pounds,andnitrification,theoxidationofNH:toNO3.ManystudiesofatmosphericdepositionimpactsonforestshavetargetedsoilNmineraIizationusingsimulatedaciddepositionundercontrolledlaboratoryconditions(T…     

荧光猝灭法测定甲硝唑片剂中的药物含量

本文利用甲硝唑可使十二烷基硫酸钠（SDS）的荧光强度猝灭,建立了荧光猝灭分光光度法测定甲硝唑含量的方法,实验结果表明：甲硝唑/SDS体系在pH=5～10缓冲溶液中,甲硝唑浓度在10μg/10mL～96μg/10mL 范围内与体系的荧光强度呈现良好的线性关系,R＝0.9981.对浓度为23.44μg/10mL的甲硝唑进行11次平行的测定,RSD＝0.92 ﹪,方法快速,简便,用于药物制剂中甲硝唑含量的测定,结果满意.     

硫肥对玉米氮、磷、钾吸收利用影响的基因型差异

以我国夏玉米主产区的34个玉米基因型(6个自交系,4个特用玉米和24个杂交种)为试验材料,通过不同硫肥供应水平的大田试验,分析了硫肥对玉米氮、磷、钾吸收利用的影响.结果表明,施用硫肥促进了玉米对营养元素的吸收,植株氮、磷、钾的积累总量平均比未施用硫肥的对照分别增加6.07%、11.89%和19.31%,肥料利用效率提高.硫肥对氮、磷、钾吸收利用的影响不完全相同,并且存在明显的基因型差异施用硫肥后,自交系氮、磷、钾的收获指数和利用效率均有大幅度提高;杂交种的氮素收获指数和利用效率均有所提高,磷素利用效率下降,但是不同基因型的变化程度差异较大;另有17个杂交种的磷素收获指数降低,10个杂交种的钾素收获指数和14个杂交种的钾素利用效率降低.