Numerical simulation for thin wall injection molding of fiber-reinforced thermoplastics

The thickness of product is less than 1mm and product compares flowing length to thickness (flow length ratio L/t) to be living above 150 of injection molding filling. This situation is called thin wall injection molding. This study uses MoldFlow software for material (PP), different processing parameters (injection time, melt temperature, mold temperature, injection pressure), various fiber (glass, long glass), different fiber ratio (40%, 50%) and different thickness (1mm, 0.9mm) to simulate the result on notebook computer. The result shows that the mold temperature is the important factor on processing. The mold temperature, melt temperature and injection pressure of thin wall injection molding are higher than convectional injection molding.     

Long wavelength MOCVD grown InGaAsN-GaAsN quantum well lasers emitting at 1.378-1.41 /spl mu/m

Low threshold InGaAsN QW lasers with lasing wavelength at 1.378 and 1.41 /spl mu/m were demonstrated by metal organic chemical vapour deposition (MOCVD). The threshold current densities are 563 and 1930 A/cm/sup 2/ for the 1.378 and 1.41 /spl mu/m emitting lasers, respectively. The significant improvement of device performance is believed due to utilisation of high temperature annealing and introduction of GaAsN barriers to suppress the resulting wavelength blue shift. A comparable characteristic temperature coefficient of the external differential quantum efficiency, T/sub 1/, is observed for the InGaAsN-GaAsN QW laser compared to similar InGaAsN/GaAs structures.     

A 60-GHz 38-pJ/bit 3.5-Gb/s 90-nm CMOS OOK Digital Radio

A 60-GHz fully integrated bits-in bits-out on–off keying (OOK) digital radio has been designed in a standard 90-nm CMOS process technology. The transmitter provides 2 dBm of output power at a 3.5-Gb/s data rate while consuming 156 mW of dc power, including the on-chip 60-GHz frequency synthesizer. A pulse-shaping filter has been integrated to support high data rates while maintaining spectral efficiency. The receiver performs direct-conversion noncoherent demodulation at data rates up to 3.5 Gb/s while consuming 108 mW of dc power, for a total average transceiver energy consumption of 38 pJ/bit in time division duplex operation. To the best of the authors' knowledge, this is the lowest energy per bit reported to date in the 60-GHz band for fully integrated single-chip CMOS OOK radios.      

Effect of extrinsic impedance and parasitic capacitance on figure of merit of RF MOSFET

This paper investigates the impact of source/drain impedance, gate-to-bulk capacitance, and gate resistance on device properties from 0 to 50 GHz for 0.13-/spl mu/m MOSFETs. Better device characteristics (g/sub m/ and C/sub gg/) can be found on MOSFETs with lower metal (or source/drain) resistance. But the best frequency characteristics (f/sub T/ and f/sub max/) occurred on MOSFETs with medium metal (or source/drain) resistance due to the increased interconnection capacitances. For radio frequency MOSFETs with finger-gate structure, better high-frequency behavior occurred on devices with medium finger-gate width W/sub f/ because of the tradeoff between gate (or source/drain) resistance and parasitic capacitance.     

A union bound on the error probability of binary codes over block-fading channels

Block-fading is a popular channel model that approximates the behavior of different wireless communication systems. In this paper, a union bound on the error probability of binary-coded systems over block-fading channels is proposed. The bound is based on uniform interleaving of the coded sequence prior to transmission over the channel. The distribution of error bits over the fading blocks is computed. For a specific distribution pattern, the pairwise error probability is derived. Block-fading channels modeled as Rician and Nakagami distributions are studied. We consider coherent receivers with perfect and imperfect channel side information (SI) as well as noncoherent receivers employing square-law combining. Throughout the paper, imperfect SI is obtained using pilot-aided estimation. A lower bound on the performance of iterative receivers that perform joint decoding and channel estimation is obtained assuming the receiver knows the correct data and uses them as pilots. From this, the tradeoff between channel diversity and channel estimation is investigated and the optimal channel memory is approximated analytically. Furthermore, the optimal energy allocation for pilot signals is found for different channel memory lengths.     

High performance BCB-bridged AlGaAs/InGaAs power HFETs

A novel low-k benzocyclobutene (BCB) bridged and passivated layer for AlGaAs/InGaAs doped-channel power field effect transistors (FETs) with high reliability and linearity has been developed and characterized. In this study, we applied a low-k BCB-bridged interlayer to replace the conventional air-bridged process and the SiN/sub x/ passivation technology of the 1 mm-wide power device fabrication. This novel and easy technique demonstrates a low power gain degradation under a high input power swing, and exhibits an improved adjacent channel power ratio (ACPR) than those of the air-bridged one, due to its lower gate leakage current. The power gain degradation ratio of BCB-bridged devices under a high input power operation (P/sub in/ = 5 /spl sim/ 10 dBm) is 0.51 dB/dBm, and this value is 0.65 dB/dBm of the conventional air-bridged device. Furthermore, this novel technology has been qualified by using the 85-85 industrial specification (temperature = 85 C, humidity = 85%) for 500 h. These results demonstrate a robust doped-channel HFET power device with a BCB passivation and bridged technology of future power device applications.     

Influence of Bulky Organo‐Ammonium Halide Additive Choice on the Flexibility and Efficiency of Perovskite Light‐Emitting Devices

Perovskite light‐emitting diodes (LEDs) require small grain sizes to spatially confine charge carriers for efficient radiative recombination. As grain size decreases, passivation of surface defects becomes increasingly important. Additionally, polycrystalline perovskite films are highly brittle and mechanically fragile, limiting their practical applications in flexible electronics. In this work, the introduction of properly chosen bulky organo‐ammonium halide additives is shown to be able to improve both optoelectronic and mechanical properties of perovskites, yielding highly efficient, robust, and flexible perovskite LEDs with external quantum efficiency of up to 13% and no degradation after bending for 10 000 cycles at a radius of 2 mm. Furthermore, insight of the improvements regarding molecular structure, size, and polarity at the atomic level is obtained with first‐principles calculations, and design principles are provided to overcome trade‐offs between optoelectronic and mechanical properties, thus increasing the scope for future highly efficient, robust, and flexible perovskite electronic device development.     

Schottky barrier thin-film transistor (SBTFT) with silicidedsource/drain and field-induced drain extension

A novel Schottky barrier thin-film transistor (SBTFT) with silicided source/drain and field-induced drain (FID) extension is proposed and demonstrated. In the new device configuration, a metal field-plate (or sub-gate) lying on the passivation oxide is employed to induce a sheet of carriers in a channel offset region located between the silicided drain and the active channel region underneath the main gate. The new device thus allows ambipolar device operation by simply switching the polarity of the bias applied to the field plate. In contrast to the conventional SBTFT that suffers from high GIDL (gate-induced drain leakage)-like off-state leakage current, the new SBTFT with FID is essentially free from the GIDL-like leakage current. In addition, unlike the conventional SBTFT that suffers from low on-off current ratio, the new device exhibits high on/off current ratio up to 10⁶ for both n- and p-channel modes of operation. Moreover, the implantless feature and the ambipolar capability of the new device also result in extra low mask count for CMOS process integration. These excellent device characteristics, coupled with its simple processing, make the new device very promising for future large-area electronic applications     

Design and fabrication of deep submicron CMOS technology compatible suspended high-Q spiral inductors

In this paper, deep submicron complementary metal-oxide-semiconductor (CMOS) process compatible high-Q suspended spiral on-chip inductors were designed and fabricated. In the design, the electromagnetic solver, SONNET, and the finite element program, ANSYS, were used for electrical characteristics, maximum endurable impact force, and thermal conduction simulations, respectively. Based on the design, suspended spiral inductors with different air cavity structures, i.e., diamond opening, circle opening, triangle opening, and full suspended with pillar supports were developed for various applications. Among these structures, the suspended inductor with pillar support possesses the highest Q/sub max/ (maximum of quality factor) of 6.6 at 2 GHz, the least effective dielectric constant of 1.06, and the lowest endurable impact force 0.184 Newton. On the other hand, the spiral inductor with diamond opening has a lowest Q/sub max/ of 4.3, the largest effective dielectric constant of 3.44 and highest endurable impact force 4 Newton. The former is suitable for station telecommunication applications in which the mechanical vibration is not a serious concern, while the latter can be used for mobile telecommunication applications subject to strong mechanical vibrations. Additionally, the conventional on-chip spiral inductor embraced by SiO/sub 2/ with a dielectric constant of 4 was prepared for comparison and found its Q/sub max/ is 3.8 at 1.2 GHz.     

A maintenance model for two-unit redundant system

In this paper, a maintenance model for two-unit redundant system with one repairman is studied. At the beginning, unit 1 is operating, unit 2 is the standby unit. The costs include the operating reward, repair cost and replacement cost, besides, a penalty cost is incurred if the system breaks down. Two kinds of replacement policy, based on the number of failures for two units and the working age, respectively are used. The long-run average cost per unit time for each kind of replacement policy is derived. Also, a particular model in which the system is deteriorative, two units are identical and the penalty cost rate is high, is thoroughly studied.