4S店创利途径新思考

汽车销售4S店模式在我国发展方兴未艾,开店家数与日俱增。如何在激烈的市场竞争中争取更大的市场份额,获得更多的利润,提高自身的盈利能力和市场竞争力是所有4S店面临的难题。本文首先分析4S店经营模式的特点,然后从增加收入、降低新车销售成本以及维修业务的成本、运营上利用政府支持政策及税收政策等方面展开阐述。具体说明可以增加4S店利润的新途径,为4S店的发展和实践提供新思路。     

Recovery of Excessive NH_3 in Black Liquor from NH_4OH-KOH Pulping of Wheat Straw

Aqueous ammonia mixed with caustic potash as wheat straw pulping liquor was investigated.The caustic potash not only reduced the NH3 usage and cooking time,but also provided a potassium source as a fertilizer in the black liquor.Excessive NH3 in black liquor from wheat straw NH4OH-KOH pulping process was recovered by batch distillation with a 98% recovery rate of free NH3 under atmospheric pressure and constant reflux.The temperature at the bottom of the column was controlled at 104-105℃.After removal of free NH3,the black liquor contained 8.4 g/L NH3-N and 7.04 g/L total potassium,with a substantial amount of ammoniacal lignin,and it could be used as a liquid fertilizer for farming.The height equivalent to a theoretical plate (HETP) of a rectifier for recovering free NH3 was calculated.The diameter and height of packing of the rectifier based on a daily consumption of 75 t oven-dry wheat straw were estimated.     

稻麦草氨法制浆工艺研究

研究了在氨水中添加少量钾碱作为蒸煮剂的稳麦草制浆新工艺，讨论了蒸煮剂的用量和配比，液固比，蒸煮最高温度，升温时间和保温时间对蒸煮效果的影响，继而确定了适宜的工艺条件，结果表明，该蒸煮体系对稻，麦草木素的脱除率达到85%。纸浆得率为稻草38.12%(细浆得率）和麦草49.65%(粗浆得率）。通过红外光谱（IR）测定了稻草蒸煮过程中木质素的结构变化。     

表面印迹磁性壳聚糖对水溶液中钍离子的吸附行为

以壳聚糖为原料,纳米Fe3O4为磁性核心,钍离子为模板剂,环氧氯丙烷为交联剂合成表面印迹磁性壳聚糖(SI-MC).红外光谱和X射线能谱分析表明:钍成功地被吸附在SI-MC上.研究吸附剂用量、溶液pH值及振荡时间对吸附过程的影响,得到最佳工艺条件.吸附数据用Langmuir等温式拟合优于Freundlich等温式,最大吸附容量为95.2 mg· g-1.与拟一级动力学模型相比,拟二级动力学模型能更好地拟合本吸附过程.吸附在SI-MC上的钍,可采用1 mol·L-1的H2SO4溶液进行有效回收处理.     

麦草NH4OH-KOH蒸煮反应历程和动力学

在合适的蒸煮工艺条件下,研究了上海朱行麦草NH4OH-KOH法制浆的反应历程和反应动力学.结果表明,脱木素过程可分为从室温升温至100°C的大量脱木素、100°C至155°C下保温45 min补充脱木素和155°C下保温45 min以后的残余脱木素3个阶段,其中65%的木素溶解在大量脱木素阶段.动力学研究表明,脱木素反应对残余木素呈表观一级、对OH-呈0.34级,反应的活化能为29.75 kJ/mol.脱木素速度方程为-dL/dt=7.602×102exp(-3 577/T)LcOH-0.34.