The concept of roll-decoupled course correction fuze with canards can provide a cost-effective solution to improve the delivery accuracy for conventional unguided ammunitions. Due to the dual-spin configuration and canards for such a projectile, the basic projectile stability theory should be extended to well perceive its behavior of motion. The seven degree-of-freedom dynamic equations of motion for the dual-spin projectile are established in the fixed-plane frame and the differential equation for the complex angle of attack is derived by the use of the projectile linear theory without the assumption of a flat trajectory. A revised stability criterion is established according to the Hurwitz stability criterion and analytic solutions of the stability boundaries for trim angles are developed. The new stability criterion can account for the possible flight instability of projectiles subjected to side forces applied at the nose, and can be reduced to the same form as the conventional spin-stabilized projectile case. Moreover, detailed trajectory simulations of two sample projectiles indicate that the new stability criterion gives satisfactory agreement with numerical results.
Microendoscopes are vital for disease detection and clinical diagnosis. The essential issue for microendoscopes is to achieve minimally invasive and high-resolution observations of soft tissue structures inside deep body cavities. Obviously, the microscope objective is a must with the capabilities of both high lateral resolution in a wide field of view (FOV) and miniaturization in size. Here, we propose a meta-objective, i.e., microscope objective based on cascaded metalenses. The two metalenses, with the optical diameters of 400 μm and 180 μm, respectively, are mounted on both sides of a 500-μm-thick silica film. Sub-micrometer lateral resolution reaches as high as 775 nm in such a naked meta-objective, with monochromatic aberration correction in a 125 μm full FOV and near diffraction limit imaging. Combined with a fiber bundle microscope system, the single cell contour of biological tissue (e.g., water lily leaf) can be clearly observed, compared to the indistinguishable features in other conventional lens-based fiber bundle systems, such as plano–convex and gradient refractive index (GRIN) cases.
Single-event effects (SEEs) in integrated circuits and devices can be studied by utilizing ultra-fast pulsed laser system through Two Photon Absorption process. This paper presents technical ways to characterize key factors for laser based SEEs mapping testing system: output power from laser source, spot size focused by objective lens, opening window of Pockels cell, and calibration of injected laser energy. The laser based SEEs mapping testing system can work in a stable and controllable status by applying these methods. Furthermore, a sensitivity map of a Static Random Access Memory (SRAM) cell with a 65 nm technique node was created through the established laser system. The sensitivity map of the SRAM cell was compared to a map generated by a commercial simulation tool (TFIT), and the two matched well. In addition, experiments in this paper also provided energy distribution profile along Z axis that is the direction of the pulsed laser injection and threshold energy for different SRAM structures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.