基于全局划分与局部划分的自适应活动轮廓模型

为了分割边界模糊图像,文章提出基于划分函数的自适应活动轮廓(Adaptive active contour model based on global division and local division,DGDL)模型.通过建立一个局部划分能量项,将其与全局划分能量项进行线性组合,并基于迭代次数建立一个自适应函数自动选取全局与局部能量,得到基于全局划分与局部划分的活动轮廓模型.利用人工合成图像与真实图像作为分割对象进行实验,结果表明,DGDL模型对初始轮廓鲁棒,迭代次数较少且耗时短,还能分割边界模糊和灰度不均图像,并具有良好的分割性能.

Recovery of lead and silver from zinc acid-leaching residue via a sulfation roasting and oxygen-rich chlorination leaching method

A large amount of acid-leaching residue is produced during the conventional Zn hydrometallurgy process,and this residue has a large concentration of a variety of valuable metals.The purpose of this study was to evaluate the ability of a procedure that entails the use of sulfation roasting,water leaching,and chlorination leaching(blowing oxygen technique)to recover Pb and Ag,followed by cooling crystallization and the replacement of Ag with lead sheet,to realize the full recovery of all valuable metals from zinc acid-leaching residue;consequently,good results were achieved.The best results were obtained under the following conditions:a sulfuric acid at 70%of the raw material quality,roasting temperature of 300°C and roasting time of 2 h,followed by the process of leaching the roasted residue for 1 h by applying a water-to-solid ratio of 5꞉1 at room temperature.The recovery rates of Zn and Fe were 98.69%and 92.36%,respectively.The main parameters of the chlorine salt leaching system were as follows:Cl−concentration of 300 g/L,Fe3+concentration of 25 g/L,acid concentration of 2 mol/L,liquid-to-solid ratio of 9 mL:1 g,temperature of 90℃,and leaching time of 0.5 h;this leaching process was followed by filtration separation.These conditions resulted in high extents of leaching for Pb and Ag(i.e.,98.87%and 96.74%,respectively).Finally,the kinetics of the process of Ag leaching using Cl−ions in an oxygen-rich medium was investigated.It was found that the leaching process was controlled by the diffusion of the product layers,and the activation energy was 19.82 kJ/mol.

离子型稀土矿硫酸镁柱浸过程中水、稀土和硫酸镁的平衡研究

采用柱浸方法研究无氨浸矿剂硫酸镁浸出离子型稀土矿,考察了浸矿过程中H2O、REO、Mg2+、SO2-4走向。结果表明,每千克稀土原矿吸水量约为344mL,稀土元素浸出率在99%以上,全过程损失率仅为0.045%,有0.24%的镁离子残留于矿体中,浸出液中镁离子总量增加4.7%,平衡率为98.76%,硫酸根总体升高0.52%。硫酸镁作为浸取剂,杂质Fe、Si的浸出率分别由硫酸铵浸矿时的0.435%、0.703%降低到0.03%、0.13%,杂质Al的浸出率基本保持不变。

专业认证背景下师范技能有效提升路径探究

以近年来各高师院校师范生在就业时存在的问题为切入点,以师范类专业认证的核心为导向,以师范专业的学生为主体,结合地方新课改对教师的实际要求,从重新定位师范生专业课的概念、加强中学题型和知识点的训练、开展师范生技能大赛、加强微格教学、及时更新师范技能训练的内容、注重板书技能的提升等方面,对提升师范生的教学技能进行探索与实践。相关研究可以为高师院校的教学改革提供实践参考。

复杂金精矿浸铜渣预处理工艺

对复杂金精矿浸铜渣硫酸和氟化氢铵预处理工艺进行研究,考察了硫酸与氟化氢铵摩尔浓度比值(R_(S/A))、摩尔浓度、反应液固比、反应时间、反应温度、搅拌速度对金银提取率的影响。结果表明,R_(S/A)和硫酸与氟化氢铵摩尔浓度是影响金银提取率的关键因素,在R_(S/A)=1/1,其摩尔浓度值升高,金、银的提取率可以得到显著提高。浸铜渣经预处理后,包裹物遭到破坏,出现蜂窝状孔隙,硅含量由原来的33.28%降低到5.49%。最佳预处理条件:R_(S/A)=1/1、摩尔浓度值1.5mol/L、反应液固比5∶1、反应时间2h、反应温度298K、搅拌速度250r/min。氰化条件:反应液固比4∶1、pH=10.5、氰化钠浓度4‰、搅拌速度300r/min、反应时间72h、反应温度298 K,此条件下,金、银的提取率分别为98.20%、95.77%,氰化残渣中金、银含量分别小于1.3g/t、50g/t。

创新创业背景下数学与统计类人才培养的改革与实践

针对创新创业背景下地方院校人才培养过程中的学生创新意识及创新能力不足、创新创业教育课程体系不完善、分级分类的人才培养体系不完备、校外产学研基地建设亟待拓展及创新创业师资力量薄弱等问题,具体指出了这些问题的表现形式,分析了产生这些问题的原因,给出了解决这些问题的具体方案。通过实践,检验了这些方案的可行性及有效性。