arXiv subjects

C. K. Lee

Publications and source records attributed to C. K. Lee.

4 recordsLinked to original sources

arXiv2019

Sampling by Reversing The Landmarking Process

Variations of the commonly applied landmark sampling are presented. These samplings are "forward" landmarking such that each stack of data is created by first selecting landmarks and then including the subsequent observations of the selected landmarks. Unlike these forward landmarking samplings, a "backward" or "reverse" landmarking is proposed with a flexible "progressive" weighting on selecting different types of events and non-events. The backward landmark sample is compared with those forward landmark samples with a real world mortgage data. Results show that the backward landmark sample has smaller sampling errors than of those forward landmark samples.

stat.AP↗

arXiv2019

Derivation of Spin Torques of the Magnetic System in Broken Inversion Symmetry

We propose a new approach to derive spin torque in systems of broken inversion symmetry. It uses the concepts of asymmetric and directional spin-spin interactions to obtain their effective fields. We applied the effective fields into the Landau-Lifshitz equation and obtained spin torques. The model offers a new and general approach for spin dynamics, one that effectively merges the Dzyaloshinskii-Moriya interaction, spin transfer torques, and spin-orbit torque into the spin dynamics equation. We discussed how our model is imposed on the spin dynamics and compared our approach with the traditional discussions on spin dynamics.

cond-mat.str-el↗

arXiv2008

Development of EHD Ion-Drag Micropump for Microscale Electronics Cooling Systems

In this investigation, the numerical simulation of electrohydrodynamic (EHD) ion-drag micropumps with micropillar electrode geometries have been performed. The effect of micropillar height and electrode spacing on the performance of the micropumps was investigated. The performance of the EHD micropump improved with increased applied voltage and decreased electrode spacing. The optimum micropillar height for the micropump with electrode spacing of 40$μ$m and channel height of 100$μ$m at 200V was 40$μ$m, where a maximum mass flow rate of 0.18g/min was predicted. Compared to that of planar electrodes, the 3D micropillar electrode geometry enhanced the overall performance of the EHD micropumps.

physics.gen-ph↗

arXiv2003

Measurement of the cross section for the reaction 127I(neutrino,electron)127Xe_(bound states) with neutrinos from the decay of stopped muons

The cross section for the reaction 127I(neutrino,electron)127Xe_(bound states) has been measured for electron neutrinos from the decay of stopped muons to be [2.84 +/- 0.91 (stat) +/- 0.25 (syst)] x 10^(-40) cm^2. A tank containing 1540 kg of 127I in the form of NaI solution was placed 8.53 m from the LAMPF beamstop where it received a typical flux of 5 x 10^7 neutrinos/(cm^2 s). The 127Xe atoms produced by neutrino capture were extracted from the target solution, placed in miniature proportional counters, and their number was determined by counting. This is the first measurement of a neutrino capture cross section for an I nucleus and is in good agreement with a recent calculation.

nucl-ex↗