稀土氧化钐对直流电沉积纳米镍铁合金箔的影响

利用直流电沉积的方法,在硫酸盐体系中制备纳米晶Ni-Fe合金镀层,研究在镀液中添加不同量的稀土氧化钐对镍铁合金箔镀层的影响.结果表明:添加氧化钐后镀层结晶细致,结构紧密,光亮度增加,添加氧化钐后并没有改变Ni-Fe合金箔的镀层结构,但使Ni-Fe合金箔的沉积速率下降,镀层的显微硬度增加;镀层中铁含量随着氧化钐含量的增加而逐渐降低,镀层耐蚀性得到提高.     

铜转炉烟灰酸浸净化液中锌的萃取分离

以p204为萃取剂,260号磺化煤油为稀释剂,从铜转炉烟灰酸浸净化液中萃取分离锌.考察萃取振荡时间、p204的体积分数、相比率(O/A)以及料液初始pH值对锌萃取率的影响.通过正交实验和单因素分析确定p204从铜转炉烟灰酸浸净化液中萃取分离锌的主要影响因素和最佳工艺条件.研究表明:室温条件下,当萃取平衡时间为6 min,p204的体积分数为30%,相比率(O/A)为2∶1,料液初始pH值为3.0时,锌的一级萃取率达到57.32%.经4级错流萃取可以将料液中锌的质量浓度降低到0.027 g/L,锌萃取率达到97.26%.负载有机相经2 mol/L的H2SO4反萃,锌可完全反萃.     

燃煤烟气中元素汞的快速检测方法研究

近年来,燃煤烟气排放的汞对环境的污染日益严重,对人类的生产与生活也造成了很大的影响,而气态元素汞作为烟气汞的主要存在形式,其分析测试研究已经引起了广泛注视。本文采用连续气体采样和冷原子荧光分光光度计直接分析测定的方法,简化配置吸收剂、采样、还原、测试的燃煤烟气元素汞检测程序,研究了配制模拟燃煤烟气中元素汞的在线测试方法。实验结果表明元素汞浓度在0~20 ng/L范围内荧光值与汞浓度呈线性关系,符合朗伯-比尔定律,方法检出限为0.009 4 ng/L,相对标准偏差均小于1%,加标回收率在96.85%~101.78%范围内,说明本方法与常规吸收采样检测方法相比,不需要吸收采样及样品处理,具有简单、快速、准确性好的优点,实现了快速检测燃煤烟气中的元素汞浓度。     

Particle simulation of the failure process of brittle rock under triaxial compression

In order to investigate the failure process of brittle rock under triaxial compression through both experimental and numerical approaches, the particle simulation method was used in numerical simulations and the simulated results were compared with those of the experiment. The numerical simulation results, such as fracture propagation, microcrack distribution, stress-strain response, and damage patterns, were discussed in detail. The simulated results under various confining pressures (0–60 MPa) are in good agreement with the experimental results. The simulated results reveal that rock failure is caused by axial splitting under uniaxial compression. As the confining pressure increases, rock failure occurs in a few localized shear planes and the rock mechanical behavior is changed from brittle to ductile. Consequently, the peak failure strength, microcrack numbers, and the shear plane angle increase, but the ratio of tensile to shear microcracks decreases. The damage formation during the compression simulations indicates that the particle simulation method can produce similar behaviors as those observed through laboratory compression tests.     

花椒籽油的微波萃取工艺研究

以花椒籽为原料、无水乙醇为溶剂用微波辅助法萃取花椒籽油,研究了溶剂用量、萃取温度、微波功率、微波处理时间等条件对花椒籽油提取率的影响。结果表明：溶剂用量1∶7（g/mL）、微波处理温度65℃、微波功率为400W、微波处理时间为3.5min的工艺条件萃取效果最好,提取率可达18.68%。将花椒籽油添加到花生油中,以花生油的过氧化值为指标进行抗氧化性能测定,结果表明花籽椒油有明显的抗氧化性能。     

三边形圆弧截面空心零件旋压成形数值模拟及试验研究

采用有限元分析软件MSC.MARC对三边形圆弧截面空心零件旋压成形进行数值模拟,对其应力应变分布规律进行了研究,重点研究了旋轮轴向进给比和毛坯厚径比对旋压成形质量的影响,分析了起皱、减薄、回弹现象产生的原因以及容易出现这些缺陷的部位。模拟及试验结果表明,口部（即成形过程中的坯料凸缘）、侧壁靠近圆角处大圆弧区和圆角区域小圆弧部位是三边形圆弧截面空心零件拉深旋压过程中易分别产生起皱、减薄和破裂的部位。     

黄土高原坡沟系统径流泥沙过程

利用概化的坡沟系统模型,采用室内放水冲刷试验,对黄土高原坡沟系统径流侵蚀产沙过程进行模拟研究。结果表明:坡沟系统的产流产沙速率随流量的增大而增大;产流量随放水量的增大呈明显的指数函数变化趋势,且增长率有增大趋势;产沙量随冲刷流量的增大呈幂函数增大趋势,增长率却逐渐减小;冲刷流量相同时,产沙速率随冲刷历时呈现出波动式的双峰增长趋势;在实验流量和时间范围内,坡沟系统的累积产沙量随累积径流量呈现出非常显著的二次函数关系.     

A preliminary study of chronology for a newly-discovered ancient city and five archaeological sites in Lop Nor,China

In the past century, it has long been debated in the archeological, historical, geographical, and many other related communities where the capital of the Luolan and Shanshan states was in the Lop Nor region. This paper presents three AMS radiocarbon ages from a newly-discovered ancient city at about 6.3 km to the northwest of the Xiaohe Graveyard, and fifteen new radiocarbon ages from the Loulan (LA), LE, Qieerqiduke, Milan, and Tuyin sites in Lop Nor. The new investigation shows that the age of newly-disco...     

解析双证书制度的推行障碍——论深化“赋能于人”的教改

衡量使命,应大力推行双证书制度,开展"赋能于人"的教改与创新,使受训者赢得更好的就业机会和就业后的发展前景。有效推行双证书制度,必须解决系统功能不适、必须破解关键障碍。     

黄原胶质量分数对受压猪肉凝胶品质的影响

将黄原胶作为脂肪替代物,采用单因素试验方法,研究超高压作用下(压力400 MPa、保压时间30 min、加压介质温度40℃)黄原胶浓度对受压猪肉凝胶保水性、色泽与质构特性的影响.结果表明,黄原胶质量分数对受压与未受压猪肉凝胶的保水性、色泽和质构参数均有显著影响(P0.05);质量分数提高,受压与未受压凝胶的保水性显著提高、各TPA参数显著下降、黄度显著增强(P0.05);在质量分数0.4%~0.6%时,受压凝胶的各质构参数均显著高于未受压组(P0.01),而在质量分数为1%时,受压凝胶的各质构参数反而显著低于未受压组(P0.05).由此说明黄原胶添加水平不同,受压凝胶的质构参数变化也不同.