Adequate facepiece fit of N95 filtering facepiece respirators (FFRs) is crucial for optimal protection against airborne pathogens. The quantitative fit test (QNFT) pass rates of the 4 N95 FFR models commonly used in Korea were below 50%. Male sex was identified as a single independent predictive factor for QNFT pass.

Infect Control Hosp Epidemiol 2018;39:104–107

A novel nano-scale manipulator capable of handling low-dimensional materials with three-dimensional linear motion, gripping action, and push–pull action of the gripper was developed for an in situ experiment in transmission electron microscopy. X-Y-Z positioning and push–pull action were accomplished by a piezotubing system, combined with a specially designed assembly stage that consisted of a lever-action gripping tip backed by a push–pull piezostack. The gripper tip consisted of tungsten wire fabricated by electrochemical etching followed by a focused ion beam process. Performance of the nano-scale manipulator was demonstrated in a grab-and-pick test of a single silver nanowire and in an in situ tensile test of a pearlitic steel sample with a specific orientation.

A new type of an iterative learning control method is proposed for dynamic systems with uncertain parameters. The method, which employs the model algorithmic control concept in the iteration sequence, is shown to be convergent for linear time-varying systems. Then the method is shown to be applicable for continuous-path control of a robot manipulator.

We investigated the differences in the interface structures and magnetotransport properties between surfactant-mediated multilayers and normal ones. From the observations of RHEED and High-Resolution X-ray diffraction patterns, we confirmed that the surfaces of Fe/Cr(100) multilayers with Pb are flatter and the interfaces are sharper than one without Pb, which means that Pb operates as an effective surfactant. The magnetoresistance(MR) ratio of the multilayers prepared with Pb was larger than that of the multilayers prepared without Pb. The change of resistance with magnetic field was larger for the multilayers with a surfactant.