Oblique Perforation of Thick Metallic Plates by Rigid Projectiles

Oblique perforation of thick metallic plates by rigid projectiles with various nose shapes is studied in this paper. Two perforation mechanisms, i.e., the hole enlargement for a sharp projectile nose and the plugging formation for a blunt projectile nose, are considered in the proposed analytical model. It is shown that the perforation of a thick plate is dominated by several non-dimensional numbers, i.e., the impact function, the geometry function of projectile, the non-dimensional thickness of target and the impact obliquity. Explicit formulae are obtained to predict the ballistic limit, residual velocity and directional change for the oblique perforation of thick metallic plates. The proposed model is able to predict the critical condition for the occurrence of ricochet. The proposed model is validated by comparing the predictions with other existing models and independent experimental data.The English text was polished by Keren Wang     

Organic SIMS with single massive gold projectile: Ion yield enhancement by silver metallization

The yield of CN from glycine rises from one CN per projectile impact to two when the sample is covered with a nominally 1 nm thick layer of silver. These yields were obtained for bombardment with Au₄₀₀⁴⁺ projectile with 136 keV impact energy. A multitude of CN-based clusters, e.g. Ag_xO_y(CN)_z are produced concurrently. As a result, a total of three CN-based secondary ions are generated per projectile impact. The exceptionally high yield for CN is of interest for biological SIMS.     

厚二氧化硅光波导薄膜制备及其特性分析

以硅烷和氧化二氮作为反应气体，采用等离子体增强化学气相沉积(PECVD)技术，不使用掺杂，在单晶硅衬底上制备了用于平面光波导的二氧化硅薄膜。研究了薄膜折射率和淀积速率与工艺参量之间的关系，通过棱镜耦合仪、傅里叶变换红外光谱、原子力显微镜等测试手段，分析了薄膜的结构和光学特性。结果表明，实验能快速生长厚二氧化硅薄膜，薄膜表面平整，颗粒度均匀，同时薄膜具有折射率精确可控和红外透射性能好的特点，非常适合制作光波导器件。     

一种新型温度自补偿高灵敏度折射率计

基于高频CO2激光脉冲写入的新型超长周期光纤光栅(ULPFG),提出了一种可实现温度自补偿的新型高灵敏度折射率计。理论与实验表明,新型超长周期光纤光栅不同闪耀阶次谐振峰对外界折射率与温度变化的灵敏度各自不同,特别的是,该光栅存在对外界折变不敏感的谐振峰,测量中除了可以利用该峰实现温度同时测量外,还可以补偿另一个测量折变的谐振峰因温度变化带来的测量误差。该折射率计具有制作简单、成本低、强度好,灵敏度高等优点,当外界折射率在1.43~1.45范围内变化时,其折射率测量灵敏度可达每单位折射率240 nm,在实际工业应用中具有较大的潜在实用价值。     

变耦合系数非线性三波导定向耦合器特性研究

报道了对高斯型及指数型变耦合系数三波导耦合器的一些重要的全光开关特性进行的研究。利用四阶龙格一库塔方法对指数型和高斯型两类变耦合系数三波导耦合器进行了数值计算。数值计算结果表明：对于变耦合系数三波导耦合器而言,功率可在波导1与波导3之间100％转换,而波导2则不可能达到100％的功率输出。与双波导变耦合系数耦合器相比,在相同的最大耦合系数情况下三波导变耦合系数耦合器开关曲线要更陡一些．即具有更好的开关特性。与平行三波导耦合器相比,变耦合系数三波导耦合器作为光开关的最大优点在于开关曲线中不存在振荡。     

射频光纤链路γ射线辐致损伤特性实验研究

由于空间环境中宇宙辐射无处不在,工作在空间环境的光纤系统必须考虑辐致损伤特性。建立了10GHz的射频光纤链路传输系统,分别采用单模光纤和保偏光纤作为传输媒质。利用60 Co`γ射线源,在剂量率1rad/s总剂量50krad下,对射频光纤链路进行辐照实验,对两种系统做对比分析。实验结果表明,单模光纤链路的辐致损耗绝对值较大,保偏光纤链路的辐致损耗绝对值较小;单模光纤的幂律模型指数较保偏光纤大,即同样的辐照剂量,单模光纤受影响程度大。在辐照起主要影响因素的阶段,单模光纤延时差受辐照影响程度较保偏光纤稍小。辐致损耗和辐致延时差对光纤长度都有线性累加作用。从整体水平看,50krad的辐射总剂量对两种光纤造成的损伤并不大,传输的信号仍在可用的范围之内。     

Coupling coefficients evaluation of a directional coupler using gain guided and index antiguided fibers

In this paper, we have investigated the mutual and self coupling characteristics of directional couplers using two individual gain guided and index antiguided fibers, which can deliver robust single mode operation with large mode area, respectively owing to the combined adequately large gain coefficients in the core; Some interesting and distinguishing properties from conventional index guided fiber couplers are obtained that: The variations of coupling coefficients are complex-valued and spatially damping oscillated, but not exponential-like decreasing as conventional index guided couplers.     

激光驾束观瞄制导仪参数检测系统

为使激光驾束观瞄制导仪各项性能参数能够在室内完成全面检测,提出了一种参数检测系统的设计方案。对参数检测系统的各组成部分分别进行了论述。该系统可检测固定焦距的激光通道与瞄准通道两轴线平行度、典型位置的输出特性、全程变焦过程中激光轴相对于瞄准轴的最大失调量,并可运用CCD图像处理技术检测激光信息场辐照度的均匀性等,具有结构简单,操作方便、检测精度高等优点。模拟试验表明,该设计方案能够满足工程中实际检测的要求。     

透过式光纤陀螺偏振特性的分析

偏振波动是谐振式光纤陀螺(R-FOG)的主要噪声之一,它对信号检测精度具有重要影响。通过矩阵法得到了透过式R-FOG中由偏振波动引起的系统零漂与偏振噪声相关参数、环形谐振腔结构参数间的关系表达式。在一定的透过式R-FOG系统结构参数下,对上述解析表达式进行了数值拟合,通过估算可满足高精度透过式R-FOG系统对偏振相关参数的要求,为偏振波动噪声的理论分析和R-FOG系统的实际搭建提供了理论基础。