High-speed digital microwave transmitter utilizing optical modulation

A novel solid-state microwave transmitter which is capable of high-speed digital modulation at high RF power levels, and yet is a simple single-stage design, has been realized. This has been accomplished by illuminating a TRAPATT diode with a stream of optical pulses from a GaAlAs laser diode.     

Electron injection in inverted organic light-emitting diodes with poly(ethyleneimine) electron injection layers

Electron-injection mechanisms from the air-stable metal-oxide cathode to light-emitting polymer layer are studied. The device configuration is aluminum (Al) doped zinc oxide (AZO)/poly(ethyleneimine) (PEI)/poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT)/molybdenum trioxide/Al, known as an inverted organic light-emitting diode (iOLED). PEI reduces the electron injection barrier between AZO and F8BT by 0.4 eV, and blocks holes at AZO(PEI)/F8BT interface in iOLEDs. The accumulation of holes at the interface greatly enhances the electron injection because of the Fowler-Nordheim type tunneling injection, leading to high current efficiency of iOLEDs.     

Optical transmission utilizing injection light sources

Although a large amount of work in optical transmission has been accomplished through the use of lasers, modern developments have enabled noncoherent light sources also to be used in this area with great success. In particular, injection light sources?in the form of the coherent injection laser and the noncoherent light-emitting diode (LED)?offer designers of optical transmission systems characteristics that are in many ways superior to those of other methods. The present article deals essentially with how injection light sources may be employed to transmit or ``communicate' information optically. Such optical techniques can be used not only in communication systems, in the classic RF sense, but in computer, video, telemetry, and detection systems as well.     

High-speed organic single-crystal transistors gated with short-channel air gaps: Efficient hole and electron injection in organic semiconductor crystals

Short-channel, high-mobility organic filed-effect transistors (OFETs) are developed based on single crystals gated with short-channel air gaps. The high hole mobility of 10 cm²/Vs for rubrene, and high electron mobility of 4 cm²/Vs for PDIF-CN₂ crystals are demonstrated even with a short channel length of 6 μm. Such performance is due to low contact resistance in these devices estimated to be as low as ～0.5 kΩ cm at gate voltage of ?4 V for rubrene. With the benefit of the short channel length of 4.5 μm in a new device architecture with less parasitic capacitance, the cutoff frequency of the rubrene air–gap device was estimated to be as high as 25 MHz for drain voltage of ?15 V, which is the fastest reported for p-type OFETs, operating in ambient conditions.     

Determination of the ionospheric electron content utilizing satellite signals

Various methods for the determination of the ionospheric electron content are possible when satellite-borne signals can be used. The paper compares the results from Doppler shift, Faraday rotation, Doppler data combined with Faraday rotation data, and topside and bottomside soundings. The often neglected prerequisite for the application of Doppler and Faraday methods is radio propagation along the same ionospheric path for the different frequencies involved. Criteria for correct application are discussed. The comparison of inflection time moments is chosen for data selection. The usage of the Doppler slopes at the time of simultaneous inflection provides reliable data of the electron content. The diurnal variation is given. The Faraday rotation rate measurement has been made a continuous one by special equipment of G. Vogt. The simultaneous use of two Doppler slopes at different frequencies and of the Faraday rotation rate at one of these frequencies results in the measurement of the effective component of the geomagnetic field. Thus, a method free from any assumptions is on hand for the electron content. From the radio-frequency sounding of the topside-sounder satellites and from simultaneous bottomside soundings a complete ionospheric profile is obtained, the integration of which results in data for the total content. A comparison of the results of the different methods is permitted within the limitations brought about by the various theoretical and experimental assumptions made.     

High-speed electron beam testing using an electron-optical phaseshift element

An electron-optical element has been developed which delays electron pulses with continuous phase shift resolution. The inherently jitter-free method relies on the change of beam potential over a length of the optical path to modify the electron pulse transit time. Direct pulse measurements using 5 ps pulses demonstrate subpicosecond resolved delays while waveforms have been measured on coplanar lines     

高速多媒体数据传输系统（上）

1 高速多媒体数据传输系统与 有线电视网的多功能开发 中国有线电视经过90年代的高速发展,已经形成了一个规模巨大的产业,成为国家的宝贵财富,如何使这些资源发挥出所蕴藏的价值,真正成为我国信息化建设的骨干网络,世纪之交的有线电视网该向什么方向发展,是各级网络经营者及业内人士十分关心的问题。     

低功耗高速差动放大器AD8132(上)

介绍了AD公司生产的一种差动放大器AD8132内部结构，并给出了多个应用电路。     

低功耗高速差动放大器AD8132(下)

介绍了AD公司生产的一种差动放大器AD8132内部结构，并给出了多个应用电路。     

High-speed coupled-cavity injection grating lasers with tailored modulation transfer functions

The modulation transfer function can be changed from broad-band to high frequency narrow-band by using a coupled cavity injection grating laser design. Higher order photon-photon resonances are utilized to tailor the modulation function well beyond the relaxation frequency.     

High-speed and low-cost carry select adders utilizing new optimized add-one circuit and multiplexer-based logic

In this paper, we propose some SQuare-RooT (SQRT) Carry SeLect Adder (CSLA) architectures including a high-speed design, a design with the lowest area compared to previous CSLAs, and two hybrid designs. The first proposed architecture is an optimized design of the Binary to Excess-1 Converter (BEC)-based CSLA by employing a new fast and merged add-one and multiplexing circuit. This architecture in addition to attaining much lower area, delay and energy consumption compared to the BEC CSLA, requires almost the same area compared to the best existing CSLA i.e. IRredundant Carry Generation and Selection scheme (IRCGS CSLA) while providing a higher speed. The second proposed CSLA as the lowest-area design is the area-optimized architecture of IRCGS CSLA that exploits a new logic optimization while maintaining its speed. This scheme makes use of a multiplexer-based logic to reduce the number of gates and to achieve a more compact design. In addition, two hybrid CSLAs are proposed by exploiting the benefits of both proposed CSLA architectures. Experimental results show that the hybrid CSLAs lead to lowest area-delay product and energy-delay product among all the proposed and previous designs in a wide range of 8-bit to 128-bit adder size. In fact, 10–48% reduction in area-delay product and 8–65% reduction in energy-delay product are achieved compared to previous designs. Moreover, the hybrid CSLAs outperform the best existing design with respect to all three parameters of area, delay and energy.     

High-speed low-power DCFL using planar two-dimensional electron gas FET technology

Planar two-dimensional electron gas FETs (TEGFETs) have been shown to have ultra-high speed and low power in DCFL circuits operating at room temperature: 18.4 ps at 900 ?W and 32.5 ps at 62 ?W. The latter result and the simplicity of the process involved are compatible with VLSI requirements.     

A THz-range planar NDR device utilizing ballistic electron acceleration in GaN

A planar and ultra-short gallium nitride (GaN) diode structure is investigated as a potential Terahertz (THz) range negative differential resistance (NDR) diode. An empirical velocity-field relation, exhibiting a peak electron velocity as high as 7 × 10⁷ cm/s, is employed to characterize the high-field transport in the simulations, accounting for ballistic electron acceleration and velocity reduction due to phonon build up. The resulting device operation is in accumulation-layer transit-time mode and large-signal circuit simulation results are reported along with discussions. Conversion efficiencies up to ∼3.4% at ∼1.5 THz are shown to be possible.     

Triode electron injection systems for hollow beams

Novel electron guns, in which a conical hollow electron beam is projected at a large angle to the axis into a coaxial deflection region, were tested. The guns have a triode structure so that the perveance can be varied easily. The strong deflection increases the effective perveance of the beam and makes the trajectories insensitive to current variations. In the form of a device with the gun at a large radius and projecting the beam inward, the electron paths are sensitive to scattering in the gun. The inverted gun, projecting the beam outward, is relatively free from this difficulty. The systems generally behave as expected, and should be quite useful for initiating variable-current hollow electron beams in various available focusing arrangements.     

A field-profile transformer utilizing a graded-index oval-core(GIO) fiber

A field-profile transformer utilizing a graded-index (GI) fiber having an oval core is proposed. Numerical investigation has demonstrated that the new fiber is capable of performing the profile transformation from elliptical fields that have high aspect ratios of up to 9, to circular fields, and vice versa. Experimental verification is also performed at a wavelength of 1550 nm, by making use of plastic GI fibers, demonstrating that a circular modal field of a standard single-mode fiber can be transformed into an elliptical field with an aspect ratio of 4.1. The transformer shows promise for low-loss coupling between fibers and functional devices that have elliptical fields, such as planar waveguides, semiconductor optical amplifiers, and laser diodes     

Yellow electroluminescent diodes utilizing poly(2,5-bis(cholestanoxy)-1,4-phenylene vinylene)

We report visible yellow light emission from diodes made from a new derivative of poly(p-phenylene vinylene). The soluble di-cholestanol derivative, poly(2,5-bis(cholestanoxy)-l, 4-phenylene vinylene), allows fabrication of the light emitting diodes by spinning the electroluminescent polymer film from solution prepared at room temperature with no subsequent processing or heat treatment required. These initial devices turn on at >8 V and have a peak emission wavelength of 570 nm at room temperature with quantum efficiencies of approximately 0.3% photons per electron.     

A high-current-gain low-temperature pseudo-HBT utilizing a sidewallbase-contact structure (SICOS)

A silicon pseudo-heterojunction bipolar transistor (HBT) with a current gain of over 100 at 77 K has been successfully fabricated using the upward operation of a self-aligned sidewall base-contact structure (SICOS). The measured characteristics agree well with the theoretical prediction, showing a negative exponential temperature dependence of current gain and a 2500-times larger collector current than in the conventional transistor at 77 K. This makes homojunction bipolar transistor operation at low temperatures feasible and has the potential to overcome the bipolar/BiCMOS limitations     

Robotic ICSI (intracytoplasmic sperm injection)

This paper is the first report of robotic intracytoplasmic sperm injection (ICSI). ICSI is a clinical procedure performed worldwide in fertility clinics, requiring pick-up of a single sperm and insertion of it into an oocyte (i.e., egg cell). Since its invention 20 years ago, ICSI has been conducted manually by a handful of highly skilled embryologists; however, success rates vary significantly among clinics due to poor reproducibility and inconsistency across operators. We leverage our work in robotic cell injection to realize robotic ICSI and aim ultimately, to standardize how clinical ICSI is performed. This paper presents some of the technical aspects of our robotic ICSI system, including a cell holding device, motion control, and computer vision algorithms. The system performs visual tracking of single sperm, robotic immobilization of sperm, aspiration of sperm with picoliter volume, and insertion of sperm into an oocyte with a high degree of reproducibility. The system requires minimal human involvement (requiring only a few computer mouse clicks), and is human operator skill independent. Using the hamster oocyte-human sperm model in preliminary trials, the robotic system demonstrated a high success rate of 90.0% and survival rate of 90.7% (n=120).     

Channel width dependence of hot electron injection program/hot hole erase cycling behavior in silicon-oxide-nitride-oxide-silicon (SONOS) memories

The channel width dependence of hot electron injection program/hot hole erase cycling behavior in silicon-oxide-nitride-oxide-silicon (SONOS) memories is investigated. While the trapped charge profile-dependent overerasure is observed in 10-μm-wide device, it is suppressed in 0.22-μm-wide device. Both the overerasure suppression and gradual positive threshold voltage shift in narrow device are explained as an elevated hot hole injection efficiency followed by more pronounced redistribution of the hole profile in the channel-center and the suppression of the lateral migration of injected holes in the channel-edge, by combining the measured endurance characteristics and TCAD simulation results. Main physical mechanisms are three-dimensional distribution of the electric field by gate/drain voltage, increasing interface states, and their trapped charge with cycling in the channel-edge.