Gate and drain currents in off-state buried-type p-channel LDDMOSFETs

The buried-type p-channel LDD MOSFETs biased at high positive gate voltage exhibit novel characteristics: (1) the ratio of the drain to gate currents is about 1×10^-3 to 5×10^-3; and (2) the gate and drain currents both are functions of only the gate voltage minus the n-well bias. Such characteristics are addressed based on the formation of the surface n ⁺ inversion layer due to the punchthrough of the buried channel to the underlying shallow p-n junction. The measured gate current is due to the Fowler-Nordheim tunneling of electrons from this inversion layer surface and the holes generated within the high-field oxide constitute the drain current. The n⁺ inversion layer surface potential is found to be equal to the n-well bias plus 0.55 V. As a result, both the oxide field and the gate and drain currents are independent of drain voltage     

Effect of calcination on characteristics and sintering behaviour of Al2O3-ZrO2 composite powders

The effect of calcination on the characteristics and sintering behaviour of zirconia-toughened alumina (ZTA) composite powders has been investigated. TiO₂ was selected as an additive to promote the sinterability of ZTA powders. The starting materials were Al₂O₃ powder, Zr(OC₃H₇)₄ and Ti(OC₃H₇)₄, and homogeneous ZTA powder containing Zr-O-Ti bonding was prepared. Calcination affected the tetragonalmonoclinic phase transformation temperature of ZrO₂ crystallizing from the gels. Calcination improved the densification rate of ZTA powder compact during sintering, which was attributed to the optimal ZrO₂ particle size and distribution on the surface of alumina. A ZTA specimen with high bulk density and high tetragonal ZrO₂ content was obtained under the conditions of 850°C/1 h calcination and 1500°C/1 h sintering.     

The adaptive fuzzy time series model with an application to Taiwan’s tourism demand

In this study, an adaptive fuzzy time series model for forecasting Taiwan’s tourism demand is proposed to further enhance the predicted accuracy. We first transfer fuzzy time series data to the fuzzy logic group, assign weights to each period, and then use the proposed adaptive fuzzy time series model for forecasting in which an enrollment forecasting values is applied to obtain the smallest forecasting error. Finally, an illustrated example for forecasting Taiwan’s tourism demand is used to verify the effectiveness of proposed model and confirmed the potential benefits of the proposed approach with a very small forecasting error MAPE and RMSE.     

Weaknesses and improvement of Wang et al.'s remote user password authentication scheme for resource-limited environments

Recently, Wang et al. showed that two new verifier-free remote user password authentication schemes, Ku-Chen's scheme and Yoon et al.'s scheme, are vulnerable to an off-line password guessing attack, a forgery attack, and a denial-of-service attack, and then proposed an improved scheme for the real application in resource-limited environments. Unfortunately, we find that Wang et al.'s scheme is still vulnerable to an impersonation attack and an off-line password guessing attack. In addition, Wang et al.'s scheme is not easily reparable and is unable to provide perfect forward secrecy. Finally, we propose an improved scheme with better security strength.     

The application of Web ATMs in e-payment industry: A case study

Today’s highly competitive marketplace is forcing the retail banking industry to optimize every possible revenue-generating opportunity. New electronic channels are replacing the more traditional ones. Web ATMs system represents one of the recent developments in financial service distribution.Through a real-life case study, this article explains how much more advantage can be achieved by enhancing Web ATMs with the latest Web-enablement technology, and examines the key benefits that can accrue from the deployment of integrated circuit (IC) card and smart card reader on Web ATMs. Last but not the least, it is expected that this article could provide strategic thinking with some apocalypses of Web 2.0 to steer the banking system for achievable changes in a direction that is consistent with the needs and expectations of a population, especially in C2C business model.     

Positive selection driving the evolution of a gene of male reproduction, Acp26Aa, of Drosophila: II. Divergence versus polymorphism

BACKGROUND: Sirolimus, a novel immunosuppressant that inhibits cytokine-driven cell proliferation and maturation, prolongs allograft survival in animal models. After a phase I trial in stable renal transplant recipients documented that cyclosporine and sirolimus have few overlapping toxicities, we conducted an open-label, single-center, phase I/II dose-escalation trial to examine the safety and efficacy of this drug combination. METHODS: Forty mismatched living-donor renal transplant recipients were sequentially assigned to receive escalating initial doses of sirolimus (0.5-7.0 mg/m2/day), in addition to courses of prednisone and a concentration-controlled regimen of cyclosporine. We conducted surveillance for drug-induced side effects among sirolimus-treated patients and compared their incidence of acute rejection episodes as well as mean laboratory values with those of a historical cohort of 65 consecutive, immediately precedent, demographically similar recipients treated with the same concentration-controlled regimen of cyclosporine and tapering doses of prednisone. RESULTS: The addition of sirolimus reduced the overall incidence of acute allograft rejection episodes to 7.5% from 32% in the immediately precedent cyclosporine/prednisone-treated patients. At 18- to 47-month follow-up periods, both treatment groups displayed similar rates of patient and graft survival, as well as morbid complications. Although sirolimus-treated patients displayed comparatively lower platelet and white blood cell counts and higher levels of serum cholesterol and triglycerides, sirolimus did not augment the nephrotoxic or hypertensive proclivities of cyclosporine. The degree of change in the laboratory values was more directly associated with whole blood trough drug concentrations than with doses of sirolimus. CONCLUSIONS: Sirolimus potentiates the immunosuppressive effects of a cyclosporine-based regimen by reducing the rate of acute rejection episodes.     

Path diversity for DS-SSMA communications in Nakagami fading channels

Average error probability and outage probability for an asynchronous direct sequence spread spectrum multiple access communications through slow nonselective Nakagami fading channels are evaluated for nondiversity and diversity receptions. Using the Gauss quadrature rule, the moments of the self-interference and the multiple access interferences are used to evaluate average error probability and outage probability. Combining the diversity technique and error correcting codes, comparisons between the uncoded nondiversity DS-SSMA system and that of the coded diversity system are shown for the Gold Code of codelength 127. Using fourth-order diversity and the Reed-Solomon code, the maximum achievable number of users is 12 percent of the codelength for Rayleigh fading, when the average probability is 10^–3. The corresponding outage probability is less than 5 percent. Performance comparisons between Rician and Nakagami fading channels are made. Since the system is interference limited, the performance seems to show no significant difference for the two fading channel models when the number of users is large.     

IrSi Schottky-barrier infrared detectors with 10-μm cutoffwavelength

IrSi Schottky-barrier detectors were fabricated with ~40-Å-thick silicide electrodes formed on p-type Si substrates by in situ processing in a conventional electron-beam evaporator. High-resolution transmission electron microscopy shows that these detectors have clean, abrupt silicide-Si interfaces. For operation at a reverse-bias voltage of 2 V, the cutoff wavelength is ~10 μm, as determined by quantum efficiency measurements     

Monolithic integration of GaAs/AlGaAs LED and Si driver circuit

A GaAs/AlGaAs LED has been monolithically integrated with a Si driver circuit composed of ten MOSFETs. The LED replaces the output pad of a 2- μm design rule, standard Si output buffer circuit, so that the overall area remains the same. By applying a stream of voltage pulses to the input of the driver circuit, the LED output has been modulated at rates exceeding 100 MHz