关于光学元件面形评价参数峰谷值(PV)的分析

 光学元件的表面面形或波前质量一般采用数字指标峰谷值PV(表面最高点和最低点之差)来评价。而两点PV在高分辨率干涉仪的测量结果中具有很大不确定性。为了更准确地评价光学元件的表面面形或波前质量,讨论了针对两点PV进行改进后的评价方式PV20,PVr,PVq。通过模拟实验证明其可以描述真实波面,并在实验中证明其可以消除灰尘等杂点对测量结果带来的干扰,以及这几种评价方式对CCD分辩率的变化不敏感,并发现上述3种方式在测量重复性方面也有较好的表现。     

Tolman length of simple droplet: Theoretical study and molecular dynamics simulation

In 1949, Tolman found the relation between the surface tension and Tolman length, which determines the dimensional effect of the surface tension. Tolman length is the difference between the equimolar surface and the surface of tension. In recent years, the magnitude, expression, and sign of the Tolman length remain an open question. An incompressible and homogeneous liquid droplet model is proposed and the approximate expression and sign for Tolman length are derived in this paper. We obtain the relation between Tolman length and the radius of the surface of tension(R_s) and found that they increase with the Rs decreasing. The Tolman length of plane surface tends to zero. Taking argon for example, molecular dynamics simulation is carried out by using the Lennard–Jones(LJ) potential between atoms at a temperature of 90 K. Five simulated systems are used, with numbers of argon atoms being 10140, 10935, 11760, 13500, and 15360, respectively. By methods of theoretical study and molecular dynamics simulation, we find that the calculated value of Tolman length is more than zero, and it decreases as the size is increased among the whole size range. The value of surface tension increases with the radius of the surface of tension increasing, which is consistent with Tolman’s theory. These conclusions are significant for studying the size dependence of the surface tension.     

激光诱导Mg等离子体电子温度的实验研究

利用波长为1 064 nm,最大能量为500 mJ的Nd∶YAG脉冲激光器在室温,一个标准大气压下对Mg合金冲击,改变激光能量,得到相应的Mg等离子体特征谱线。分析谱线,发现谱线有不同的演化速率,同时得到了MgⅠ,MgⅡ离子谱线,证明此实验条件下,激光能量足够Mg合金靶材充分电离。选择了相对强度较大的MgⅠ 383.2 nm, MgⅠ 470.3 nm, MgⅠ 518.4 nm三条激发谱线,利用这些发射谱线的相对强度计算了等离子体的电子温度,激光能量为500 mJ时,等离子体温度为1.63×104 K。实验结果表明：在本实验条件下,Mg原子可以得到充分激发;在200～500 mJ激光能量范围内,等离子体温度随着激光能量的降低而衰减,在350～500 mJ激光能量范围内的等离子体温度随激光能量的变化速度十分明显,200～350 mJ时等离子体温度变化速度迅速减缓;激光能量为300 mJ时,谱线相对强度明显减弱,低于350和250 mJ的谱线相对强度,不符合谱线相对强度会随着激光能量提高而上升的变化趋势,证明发生了等离子体屏蔽现象,高功率激光产生的等离子体隔断了激光与材料之间的耦合。此时的等离子体温度明显升高,不符合变化趋势,这是由于在发生等离子体屏蔽现象时,激光能量被等离子体吸收,导致等离子体温度上升。     

Remote excitation and remote detection of a single quantum dot using propagating surface plasmons on silver nanowire

Using propagating surface plasmons(SPs) on a silver nanowire(NW), we demonstrate that a focused laser light at the end of the silver NW can excite a single quantum dot(QD) microns away from the excitation spot. The QD–NW interaction allows the excited QD convert part of its energy into propagating SPs, which then can be detected at remote sites.Simultaneous multi-QD remote excitation and remote detection can also be realized. Furthermore, the tight confinement of the propagating SPs around the NW surface enables the selective excitation of QDs very close in space, which cannot be realized under the conventional excitation condition. This remote excitation and remote detection approach may find applications in optical imaging and the sensing of chemical and biological systems.     

钢铁检测微型光谱仪的研制

针对国内光电直读型钢铁检测微型光谱仪研究的不足,提出基于Czerny-Turner结构的系统设计方法,讨论了优化方法及验证方法,并加工出了光谱仪。光谱仪采用三次多项式拟合标定波长,实测分辨率在436 nm~608 nm全谱段达0.225 nm、中心谱段达0.135 nm,基本满足钢铁检测要求。提出一种基于多帧判断的定性分析方法,7种待测元素检出限优于1.5%,通过建立拟合光谱数据库实现半定量分析,25种样品检测精度达2%,为钢铁牌号识别提供重要参考。     

重离子治癌的磁扫描照射野形成法

在论述重离子治癌照射的基本思想及其特点的基础上,着重对磁扫描照射野形成的两种技术路线——点扫描和栅扫描的优缺点进行了分析阐述.初步给出了 HIRFL上的重离子治癌终端磁扫描相关参数. The basic principle and characteristic of irradiation in heavy ion radiotherapy are introduced. Based on the basic principle and characteristic of irradiation in heavy ion radiotherapy, two magnetic scan methods for creating uniform irradiation field--the spot scan and the raster scan, are compared briefly. The parameter requests to the magnetic scanning system of the heavy ion radiotherapy facility planned in IMP(Institute of Modern Physics) are presented.     

重离子辐照对人肝癌HepG2细胞蛋白质组图谱的影响

分别制备经1 Gy C离子辐照和未经辐照人肝癌HepG2细胞的总蛋白样品, 采用固相pH梯度双向凝胶电泳技术进行蛋白分离, 用ImageMaster 2D双向电泳凝胶图像分析软件分析数字化图谱。 结果显示, 差异表达的蛋白质点为17个, 其中1个仅在未经C离子辐照的HepG2细胞中表达, 8个蛋白质点在辐照后的细胞中表达上调, 8个蛋白质点在辐照后的细胞中表达下调。 建立了重复性较好和分辨率较高的分离HepG2细胞总蛋白的双向电泳技术。 实验结果表明, C离子辐照HepG2细胞后其蛋白质组发生了改变。     

煤油氧气脉冲爆震火箭发动机爆震特性

脉冲爆震火箭发动机(PDRE)是一种利用脉冲式爆震波产生高温、高压燃气发出的冲量来产生推力的推进系统.与常规液体火箭发动机相比,脉冲爆震火箭发动机具有更高的性能,并且结构更简单.本文以航空煤油为燃料、氧气为氧化剂、压缩氮气为隔离气体,并利用电磁阀控制燃料、氧化剂和隔离气体的间歇式供给.利用低的点火能量(50mJ),在内径50mm,长度1.1m的爆震管内进行了大量的多循环爆震试验,研究煤油氧气电磁阀脉冲爆震火箭发动机的爆震波特性.研究结果为进一步研究气液两相多次爆震燃烧机理提供了依据,为研制工程应用的PDRE提供理论和实践基础.