Hybrid electric vehicles (HEVs) require supervisory controllers to distribute the propulsion power from sources like an engine and motors. Control concepts based on optimal control theories such as ...dynamic programming (DP) and Pontryagin’s minimum principle (PMP) have been studied to maximize fuel efficiencies. These concepts are, however, not practical for real-world applications because they guarantee optimality only if future driving information is given prior to the actual driving. Instead, heuristic rule-based control concepts are widely used in real-world applications. Those concepts are not only simple enough to be designed based on existing vehicle control concepts, but also allow developers to easily intervene in the control to enhance other vital aspects of real-world vehicle performances, such as safety and drivability. In this study, a rule-based control for parallel type-2 HEVs is developed based on representative control concepts of real-world HEVs, and optimal control parameters are determined by optimization processes. The performance of the optimized rule-based control is evaluated by comparing it with the optimal results obtained by PMP, and it shows that the rule-based concepts can achieve high fuel efficiencies, which are close, typically within 4%, to the maximum values obtained by PMP.
The
in situ
intermetallic compound (IMC) growth in Cu pillar/Sn bumps was investigated by isothermal annealing at 120°C, 150°C, and 180°C using an
in situ
scanning electron microscope. Only the Cu
6
...Sn
5
phase formed at the interface between the Cu pillar and Sn during the reflow process. The Cu
3
Sn phase formed and grew at the interfaces between the Cu pillar and Cu
6
Sn
5
with increased annealing time. Total (Cu
6
Sn
5
+ Cu
3
Sn) IMC thickness increased linearly with the square root of annealing time. The growth slopes of total IMC decreased after 240 h at 150°C and 60 h at 180°C, due to the fact that the Cu
6
Sn
5
phase transforms to the Cu
3
Sn phase when all of the remaining Sn phase in the Cu pillar bump is completely exhausted. The complete consumption time of the Sn phase at 180°C was shorter than that at 150°C. The apparent activation energy for total IMC growth was determined to be 0.57 eV.
Fine-pitch Cu pillar bumps have been adopted for flip-chip bonding technology. Intermetallic compound (IMC) growth in Cu pillar bumps was investigated as a function of annealing or current stressing ...by
in situ
observation. The effect of IMC growth on the mechanical reliability of the Cu pillar bumps was also investigated. It is noteworthy that Sn exhaustion was observed after 240 h of annealing when current stressing was not applied, and IMC growth rates were changed remarkably. As the applied current densities increased, the time required for complete Sn consumption became shorter. In addition, Kirkendall voids, which would be detrimental to the mechanical reliability of Cu pillar bumps, were observed in both Cu
3
Sn/Cu pillars and Cu
3
Sn/Cu under-bump metallization interfaces. Die shear force was measured for Cu pillar samples prepared with various annealing times, and degradation of mechanical strength was observed.
The reaction between Cu pillar and eutectic SnPb solder during isothermal annealing was studied systematically. Intermetallic compounds (IMCs), such as Cu
6
Sn
5
and Cu
3
Sn, were formed in between ...Cu and SnThe parabolic rate law was observed on IMC formation, which indicated that the growth of IMCs was controlled by atomic diffusion (a diffusion-limited process). Annealing at 165 °C for 160 h decreased the growth rate of Cu
6
Sn
5
, and at the same time increased the growth rate of Cu
3
Sn. This was when Sn in solder was exhausted completely. The activation energies for the growth of Cu
3
Sn and Cu
6
Sn
5
were measured to be 1.77 eV and 0.72 eV, respectively. The Kirkendall void that formed at the interface between Cu pillar and solder obeyed the parabolic rate law. The growth rate of the Kirkendall void increased when the Sn in solder was consumed in its entirety.
MST (mesosphere, stratosphere, troposphere) radar observations at Jicamarca use four antenna beams, one vertical, others tilted to the east, west, and south, to detect the scattered pulse returns ...from mesospheric heights (∼55–85 km). Doppler shifts of scattered returns, estimated by fitting the observed signal spectra by generalized Gaussian‐shaped models, are used to estimate mesospheric wind vectors. At some heights two spectral peaks are seen in which case a dual‐peaked model is fitted the spectrum. Dual peaks are more common for returns from the east and west tilted beams with stronger sidelobes. When sidelobe‐caused peaks are dominant and are mistaken for mainlobe peaks, wind errors occur since the estimation algorithm uses the pointing angle of the mainbeam. To avoid such errors we implemented a clustering‐based machine learning procedure to identify and use only the mainbeam components of dual‐peaked spectra. Wind estimates made before and after the procedure will be presented to assess the improvements achieved by this new method to be used routinely in Jicamarca mesospheric wind measurements and applied to past MST data.
Key Points
Radar antenna beam sidelobe contaminations cause dual‐peaked Doppler spectra to be detected in Jicamarca radar MST probing
Sorting the mean Doppler shifts and related power of detected spectral peaks into mainlobe and sidelobe sets is required in wind estimation
We use weighted least squares fits of dual‐peaked spectra followed by sorting and classification steps to obtain bias free wind estimates
The Korean Peninsula is located in the far-eastern Eurasian plate margin where crustal structures vary laterally, causing significant raypath-dependent modulations of crustal phases. The ...discriminative variations of crustal phases hinder application of conventional local magnitude scales in the continental margin. The mantle-lid phase is less affected by the crustal structures than the crustal phases, providing a better constraint to magnitude estimation. A regional body-wave magnitude scale based on the mantle-lid P wave (Pn), m sub(b)(Pn), is developed for regional events around the Korean Peninsula. The m sub(b)(Pn) scale is determined to be m sub(b)(Pn) = 0.380 ( plus or minus 0.299) + log A + 2.012 ( plus or minus 0.122) log d, where A is the peak-to-peak Pn amplitude in mu m and d is the epicentral distance in km. The m sub(b)(Pn) estimates of regional events around the Korean Peninsula are determined. The m sub(b)(Pn) estimates are compared with other available magnitude estimates (m sub(b)(Lg), M sub(L)). The influence of structures beneath stations on Pn amplification is investigated from inter-station magnitude residuals. A characteristic spatial variation of inter-station magnitude residuals with strengths mostly between -6 and 6 %, but with maximum strengths of plus or minus 10 %, is observed. The inter-station magnitude residuals appears to be correlated well with geological and seismic structures in the crust.
The Korean Peninsula is located in the far-eastern Eurasian plate margin where crustal structures vary laterally, causing significant raypath-dependent modulations of crustal phases. The ...discriminative variations of crustal phases hinder application of conventional local magnitude scales in the continental margin. The mantle-lid phase is less affected by the crustal structures than the crustal phases, providing a better constraint to magnitude estimation. A regional body-wave magnitude scale based on the mantle-lid P wave (Pn), m ^sub b^(Pn), is developed for regional events around the Korean Peninsula. The m ^sub b^(Pn) scale is determined to be m ^sub b^(Pn) = 0.380 (±0.299) + log A + 2.012 (±0.122) log d, where A is the peak-to-peak Pn amplitude in μm and d is the epicentral distance in km. The m ^sub b^(Pn) estimates of regional events around the Korean Peninsula are determined. The m ^sub b^(Pn) estimates are compared with other available magnitude estimates (m ^sub b^(Lg), M ^sub L^). The influence of structures beneath stations on Pn amplification is investigated from inter-station magnitude residuals. A characteristic spatial variation of inter-station magnitude residuals with strengths mostly between -6 and 6 %, but with maximum strengths of ±10 %, is observed. The inter-station magnitude residuals appears to be correlated well with geological and seismic structures in the crust.PUBLICATION ABSTRACT
The Korean Peninsula is located in the far-eastern Eurasian plate margin where crustal structures vary laterally, causing significant raypath-dependent modulations of crustal phases. The ...discriminative variations of crustal phases hinder application of conventional local magnitude scales in the continental margin. The mantle-lid phase is less affected by the crustal structures than the crustal phases, providing a better constraint to magnitude estimation. A regional body-wave magnitude scale based on the mantle-lid
P
wave (
Pn
),
m
b
(
Pn
), is developed for regional events around the Korean Peninsula. The
m
b
(
Pn
) scale is determined to be
m
b
(
Pn
) = 0.380 (±0.299) + log
A
+ 2.012 (±0.122) log
d
, where
A
is the peak-to-peak
Pn
amplitude in μm and
d
is the epicentral distance in km. The
m
b
(
Pn
) estimates of regional events around the Korean Peninsula are determined. The
m
b
(
Pn
) estimates are compared with other available magnitude estimates (
m
b
(
Lg
),
M
L
). The influence of structures beneath stations on
Pn
amplification is investigated from inter-station magnitude residuals. A characteristic spatial variation of inter-station magnitude residuals with strengths mostly between −6 and 6 %, but with maximum strengths of ±10 %, is observed. The inter-station magnitude residuals appears to be correlated well with geological and seismic structures in the crust.
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