We compile a blue AGN sample from SDSS and investigate the ratio of hard Xray to bolometric luminosity in dependence on Eddington ratio and black hole mass. Our sample comprises 240 radio-quiet Seyfert 1 galaxies and QSOs. We find that the fraction of hard X-ray luminosity (log(L2−10kev/Lbol)) decreases with the increase of Eddington ratio. We also find that the fraction of hard X-ray luminosit...

We develop and characterise new high-performance nano-engineered magneto-optic materials for use in lasermicroscopy-based magnetic field visualisers featuring high sensitivity and resolution, low cost and small size. This type of visualisers will make it possible for forensic experts to recover erased data previously stored in highand ultrahigh-density magnetic disks and hard disk drives.

This paper considers the issue of modeling the pivot nonlinearity in a typical hard disk drive, taking into account viscous friction, Coulomb friction and hysteresis effects. It presents a nonlinear compensator design, based on a proposed model, to make the compensated system behave like a double integrator regardless of the magnitude of the input current. It describes extensive experiments, ca...

In this paper, a novel portable hard-disk encryption/decryption system with a MEMS coded lock is presented, which can authenticate the user and provide the key for the AES encryption/decryption module. The portable hard-disk encryption/decryption system is composed of the authentication module, the USB portable hard-disk interface card, the ATA protocol command decoder module, the data encrypti...

The magnetic hard disc drive industry continues to face serious challenges in its quest for ever decreasing bit size. This review summarizes recent advances and promising new technology which have foundations in fundamental physical principles. Some advantages of these new ideas are illustrated through micromagnetic modeling and the numerous challenges associated with their implementation are h...

this article proposed a methodology for computer numerical control (CNC) machine scoring. The case study company is a manufacturer of hard disk drive parts in Thailand. In this company, sample of parts manufactured from CNC machine are usually taken randomly for quality inspection. These inspection data were used to make a decision to shut down the machine if it has tendency to produce parts th...

Benchmarked hard disk drive performance characterization and optimization based on Design of Experiments techniques Yu-wei Lin This paper describes an experimental study offered by Designs of Experiments (DOE) within the defined factor domains to evaluate the factor effects of simultaneous characteristics on the benchmarked hard disk drive performance by proposing well-organized statistical mod...

This paper proposes a new TDOF control scheme to minimize the tracking error caused by the neglected vibration modes of the plant. The design parameter is optimized from experimental data. The effectiveness is shown by simulation using a precise model of hard disk drive. Copyright c ©2005 IFAC.

Recently, disk zoning techniques have been widely used for increasing disk drive capacity. As a side effect, data transfer rates for outer zones of a hard disk are much higher than those of inner zones. Without giving proper care to disk zoning features, disk bandwidth cannot be utilized e ectively. In this paper, we propose a data placement scheme for VBR (Variable Bit Rate) video objects, cal...

The integrity of data stored on a hard disk is typically verified by computing the chained hash value of disk sector data in a specific order. However, this technique fails when one or more sectors turn bad during storage, making it impossible to compute their hash values. This paper presents a k-dimension hashing scheme, which computes and stores multiple hash values for each hard disk sector....