Transient optical properties in fused silica measured by time-resolved high-power laser photometer

A time-resolved high-power laser photometer, which measures the real-time variations of transmission, internal reflection, and scattering simultaneously with picosecond time resolution, was developed to investigate the material response sequence during high-power nanosecond laser irradiation in thick fused silica. It was found that the transient transmission decreased sharply, accompanied by an increase in internal reflection at the rising edge of the laser pulse. The transient transmission recovered, while laser damage did not occur, but it did not recover if the scattering increased, indicating the occurrence of laser damage. The reason for the sharp decrease of transmission and the relationship between the transmission drop and laser damage were discussed.     

正丁基正辛基亚砜萃取Au(Ⅲ)的NMR波谱研究

以亚砜的模型化合物正丁基正辛基亚砜液-液萃取Au(Ⅲ),对萃取剂及萃取配合物的1H NMR、13C NMR波谱特征进行讨论,研究了萃取时萃合物的结构及其动态变化.作者认为有机相中存在Au(Ⅲ)在正丁基正辛基亚砜(BOSO)与配合物之间快速交换的过程,该过程有利于Au(Ⅲ)从水相向有机相转移,也是形成NMR波谱特征的主要原因.核磁共振实验也说明了在两种酸度下Au(Ⅲ)均与亚砜基团中的氧原子配位,但萃取机理有所不同,核磁共振波潜的分析给出了萃取机理的直接证据.     

高分子亚砜树脂的合成及XPS方法对萃金机理的研究

对氯甲基聚本乙烯树脂进行改性,与硫醇化合物反应氧化合成一种高分子亚砜树脂化合物,用FT-IR、XPS等方法表征了该化合物的结构组成.将亚砜物质直接用于含Au溶液的萃取,萃取率达95%.用一种新的研究方法XPS法研究了萃取机理.该亚砜树脂具有性能稳定、合成简便、固定相单一、萃取率高等特点.     

亚砜的合成及其含量的确定

亚砜类物质是重要的化工原料,在医药、冶金和合成等方面得到广泛应用.为了研究亚砜在贵金属中的萃取机理,实验合成了对称及不对称的亚砜,本文介绍了一种不对称亚砜的合成及其结构表征.并用MS、FT-IR、1H NMR和13C NMR手段确定了它的结构是正丁基正辛基亚砜(BOSO).在合成中,亚砜易氧化成砜,不易控制,在硫醚氧化生成亚砜与砜后,必须有简捷的方法测出它们的含量,以便优化合成条件,减少生成砜的副反应,提高亚砜的产率,并保证所获亚砜的纯度.传统的方法是利用自动电位滴定法测定亚砜硫含量[1],此方法烦琐,时间长,重复性差;近年来也有用气液色谱[2],其原理是用内标法,实验条件要求是易挥发,难分解的样品,但此方法标样不易获得,并且样品要求高.1H NMR方法的原理是:积分曲线面积与引起该组峰的核数成正比关系,其优点是,不需要引进任何校正因子或绘制工作曲线,可直接根据各共振峰的积分面积的比值,得到两者含量之比,并且在有其他杂质存在且不与亚砜和砜的特征峰相重合的情况下,采用标准加入法可得到亚砜和砜的各自含量.为此,本文介绍了在BOSO的合成中的应用实例.     

Numerical model and experimental demonstration of high precision ablation of pulse CO_2 laser

To reveal the physical mechanism of laser ablation and establish the prediction model for figuring the surface of fused silica, a multi-physical transient numerical model coupled with heat transfer and fluid flow was developed under pulsed CO_2 laser irradiation. The model employed various heat transfer and hydrodynamic boundary and thermomechanical properties for assisting the understanding of the contributions of Marangoni convention,gravitational force, vaporization recoil pressure, and capillary force in the process of laser ablation and better prediction of laser processing. Simulation results indicated that the vaporization recoil pressure dominated the formation of the final ablation profile. The ablation depth increased exponentially with pulse duration and linearly with laser energy after homogenous evaporation. The model was validated by experimental data of pulse CO_2 laser ablation of fused silica. To further investigate laser beam figuring, local ablation by varying the overlap rate and laser energy was conducted, achieving down to 4 nm homogenous ablation depth.     

流动注射在线共沉淀HG-AFS测定地质样品中痕量锡

建立了流动注射在线共沉淀HG AFS测定痕量锡的分析方法。方法基于锡在碱性介质中与氢氧化镁共沉淀 ,沉淀收集在锥形沉淀腔中 ,用HCl溶洗沉淀和NaBH4反应 ,产生的氢化物被载气引入原子化器中进行测定。测定锡的相对标准偏差为 5 15 % ( 3 0ng·mL-1,n =10 ) ,检出限为 0 2 1ng·g-1,检出限较直接进样降低了 12倍。对国家标准参考物中锡的测定结果与标准值相符。     

徒骇河聊城大学段水质情况的检测

徒骇河是流经聊城地区的一条主要河流,将其作为研究对象,在不同地点取样,对其水质进行了实验检测。结果显示,徒骇河水质只符合国家Ⅳ或Ⅴ类水的标准,即一般工业或农业用水及景观用水等。因此,长期饮用此水或用于灌溉农田都会对居民及农作物甚至当地的生态环境带来严重的负面影响。     

磁性硫化胶的成分鉴定

用ＦＴ－ＩＲ和ＧＣ－ＭＳ方法分析检测磁性橡胶的热裂解液,结合Ｂｅｉｌｓｔｅｉｎ铜丝实验,对其并用胶成分和助剂进行鉴定。该方法可推广应用于其它并用胶。     

4 MV激光触发多级多通道开关特性

报道了4 MV激光触发多级多通道开关的结构设计和初步的实验结果及分析。该开关采用轴向聚焦触发方式，设计为匀场结构，采用场调整环与匀压环调整开关间隙电场分布，电极-绝缘子序列采用堆栈结构替代榫接结构，独立定位、紧固。实验结果表明:4 MV激光触发多级多通道开关的自击穿电压偏差小于5%，自击穿电压与工作气压呈良好的线性关系；触发延迟时间约25 ns，极差小于±2.5 ns，抖动1.5 ns；等工作电压-气压比条件下，随着气压和工作电压的上升触发延迟时间及其抖动趋向下降。