1,721,029 research outputs found
Thickness minimized magnetic circuit for rotary-type voice coil motor
No full textAs the demand for small-form-factor disk drives for mobile devices increases, the miniaturization of voice coil motor (VCM) actuators playing important roles in track seeking and track following is an issue. In this study, we have determined that a multisegmented magnet array (MSMA) can reduce the total thickness of the magnetic circuit for a rotary-type VCM without changing the coil and air gap parameters
Comparison of the clinical characteristics and treatment outcomes of patients requiring hospital admission to treat eosinophilic and neutrophilic exacerbations of COPD [Corrigendum]
No full textKang HS, Rhee CK, Kim SK, Kim JW, Lee SH, Yoon HK, Ahn JH, Kim YH. Int J Chron Obstruct Pulmon Dis. 2016;11:2467–2473.Page 2467, Abstract, Results section, line 1, the text “COPD exacerbations (177 eosinophilic and 380 neutrophilic) were included” should read “COPD exacerbations (177 eosinophilic, 380 neutrophilic and 48 paucigranulocytic) were included. Of these, we compared patients with eosinophilic and neutrophilic COPD exacerbations”.Read the original articl
A neural network approach based on interference pattern analysis: Application to an autoalignment method for the focusing unit of NFR system
No full textFrom the viewpoint of assembly, evaluation results and an autoalignment method for the focusing unit (FU) of a near-field recording (NFR) system are proposed. Generally, the size of the focusing unit composed of the objective lens and the solid immersion lens is smaller than that of the conventional focusing unit. Hence there are difficulties in the precise assembly of the small focusing unit. We developed an evaluation system with an interferometer and evaluated some focusing unit samples, then a tolerance analysis of the assembly error between the SIL and the objective lens and an interference pattern analysis of the assembly error were carried out. A pattern recognition method using a neural network is presented with features, which were extracted from interference patterns due to errors in the FU
A new active clamping zero-voltage switching PWM current-fed half-bridge converter
No full textA new active clamping zero-voltage switching (ZVS) pulse-width modulation (PWM) current-fed half-bridge converter (CFHB) is proposed in this paper. Its active clamping snubber (ACS) can not only absorb the voltage surge across the turned-off switch, but also achieve the ZVS of all power switches. Moreover, it can be applied to all current-fed power conversion topologies and its operation as well as structure is very simple. Since auxiliary switches in the snubber circuit are switched in a complementary way to main switches, an additional PWM IC is not necessary. In addition, it does not need any clamp winding and auxiliary circuit besides additional two power switches and one capacitor while the conventional current-fed half bridge converter has to be equipped with two clamp windings, two ZVS circuits, and two snubbers. Therefore, it can ensure the higher operating frequency, smaller-sized reactive components, lower cost of production, easier implementation, and higher efficiency. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 200-W, 24-200 Vdc prototype are presented
Synthesis of 5,6-dihydro[1,10]phenanthroline derivatives and their properties as hole-blocking layer materials for phosphorescent organic light-emitting diodes
Full text linkTo develop new hole-blocking materials for phosphorescent organic light-emitting diodes (PhOLEDs), 5,6-dihydro-2,9-diisopropyl-4,7-diphenyl[1,10]phenanthroline (1) and 5,6-dihydro-2,9-diisopropyl-4-(4-methoxyphenyl)-7-phenyl[1,10]phenanthroline (2) were synthesized. While the absorption spectrum of I is very similar to that of 2, the photoluminescence spectrum of 1 has the feature of the narrower and blue-shifted blue-violet emission at the peak of 356 rim, compared to that of 2. The HOMO and LUMO energy levels of 1 and 2 were estimated from the measurement of cyclic voltanimetry, and 1 has the appropriate levels for a hole-blocking layer (HBL). The use of 1 as a HBL in a green PhOLED led to good efficiency of 23.6 cd/A at 4.4 mA/cm(2)..This research was supported by
CMDS, KOSEF and MOCIE. In particular, HWL appreciates
the financial support from Nuri research project
Multisegmented magnet array on voice coil motor in rotating data storage devices
No full textThe swing-arm-type voice coil motor (VCM) is widely used as an actuator in rotating data storage devices. Recently, it has been found that to achieve a faster data transfer rate and a higher data storage areal density, a high performance actuator is required. Moreover, a small form factor has become desirable for portable devices. In this paper, a novel magnetic circuit of VCM with multisegmented magnet array (MSMA) is proposed. Both the magnetic circuits of the conventional VCM and the MSMA VCM are optimized using the 3D finite element method. Sample magnetic circuits are fabricated with optimally designed parameters and a comparative analysis is carried out. The performances of magnetic circuits are evaluated and the experimental results prove the effectiveness of the proposed magnet array
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