上海地区不同施肥方式氮磷随地表径流流失研究

选择上海宝山罗店镇具有代表性的旱地蔬菜农田生态系统,在从2004年3月到8月的近半年时间里,通过对径流及径流中侵蚀泥沙的氮磷流失情况的连续监测与实验分析,研究了旱地农田施肥与氮磷流失污染之间的关系,探讨了农田氮磷的迁移特征及环境效应,主要结果表明:随地表径流流失的总氮、总磷,流失形态以沉积相为主,大部分是当季施用的化肥,随径流排出农田的氮素中有37.7%是当季施用的氮素化肥,磷素中有26.9%是当季施用的磷素化肥。     

川西北高寒沙化草地围栏禁牧时段和恢复过程的耦合机理研究

川西北沙化草地在围栏禁牧生态恢复过程中,土壤中有机质、全氮、水解性氮变化特征,研究对象为:未修复沙化草地、围栏禁牧生态恢复时间分别为5年、10年的沙化草地,研究其不同围栏禁牧时间沙化草地0～40 cm土层土壤中有机质、全氮、水解性氮的变化.其结果表明,随着围栏禁牧时间的增长,各土层土壤有机质、全氮含量均增加,植被盖度、...     

沙棘鲜果渣真空干燥技术研究

为研究沙棘鲜果渣在真空干燥条件下的干燥特性,进而确定适宜的工艺参数,笔者选用了不同的干燥温度、真空度和物料厚度对沙棘鲜果渣进行脱水干燥试验,测定不同干燥工艺条件下沙棘果渣的干燥特性,并对干燥后沙棘果渣的总黄酮和原花青素含量进行测定。试验结果表明,适宜的沙棘鲜果渣真空干燥工艺条件为:干燥温度60℃,真空度80 k Pa,物料厚度1. 0 cm.干燥后的沙棘果渣总黄酮含量最高达4. 98 mg/g,原花青素含量最高达35. 67 mg/g.     

遥感植被指数在重点国有林区“三总量”伐区检查中的应用研究——以对鹤立林业局的研究为例

以鹤立林业局为研究区域,以2007年"三总量"检查的TM遥感判读区划结果和抽样现地检查结果为基础资料,分析了同期遥感数据之间、不同年份遥感数据之间采伐地块的植被指数变化,以及不同采伐方式和不同采伐强度与植被指数变化的关系,为利用遥感数据进行"三总量"检查进行了有益的探索和实践。     

基于全站仪精准量测树木材积方法初探

笔者根据北京林业大学冯仲科教授提出的精准林业的理念,使用全站仪对树木材积进行量测,并将全站仪量测的材积数据与解析法所得砍伐数据进行比较,结果表明,全站仪量测立木材积的精度在91%以上,平均精度在96%左右,完全能满足高精度量测立木材积的要求,建议推广应用。     

Transdermal behaviors comparisons among Evodia rutaecarpa extracts with different purity of evodiamine and rutaecarpine and the effect of topical formulation in vivo

Aim

Evodiamine (EVO) and rutaecapine (RUT), the major active components from Evodia rutaecarpa extract (EE), are recognized as a depended analgesic agent. This study was designed to investigate the effect of purity and chemical enhancers on the transdermal behavior of EVO and RUT, and the pharmacological effect of their topical cream in vivo.

Material and methods

Transdermal delivery across a full thickness pig abdominal skin was detected in vitro by Franz-type diffusion cell, with HPLC for quantification of the permeation of EVO and RUT. The activity of topical cream in vivo was evaluated by a mice pain model induced by formalin and hot plate.

Results

Transdermal characters of EVO and RUT showed a low transdermal rate, long lag time and low cumulative amount. The transdermal rate and cumulative amount could be promoted by lipophilic enhancers, whereas lag time was shortened by hydrophilic surfactant, but these permeation parameters were not markedly influenced by purity of EE (p > 0.05). The effect in vivo was confirmed by analgesic models in topical cream of EE, which produced a significant (p < 0.05) inhibitory effects on pain response in dose-dependent manner.

Conclusion

The purity of EVO and RUT from EE has no significant effect on their permeation through porcine skin, but oleic acid or nerolidol can markedly elevate the transdermal rate of EVO and RUT. High purity of EE is the best choice for topical preparation to increase the drug loading. The effect of EE in vivo is verified by formalin model and hot plate test.     

运输问题最优方案探讨

运用两种方法即最小元素法和最大最小元素法。求运输问题的最优方案。最小元素法编制初始方案只考虑运价:最大最小元素法编制初始方案既考虑运价,又同时考虑了供求量。两种方法编制初始方案出发点不同,通过调整、改进,最终得到的使总运费最少的最优方案就不一样。因此,运输问题最优方案不是唯一的。