A low-cost CMOS programmable temperature

A novel uncalibrated CMOS programmable temperature switch with high temperature accuracy is presented. Its threshold temperature T-th can be programmed by adjusting the ratios of width and length of the transistors. The operating principles of the temperature switch circuit is theoretically explained. A floating gate neural MOS circuit is designed to compensate automatically the threshold temperature T-th variation that results form the process tolerance. The switch circuit is implemented in a standard 0.35 mu m CMOS process. The temperature switch can be programmed to perform the switch operation at 16 different threshold temperature T(th)s from 45-120 degrees C with a 5 degrees C increment. The measurement shows a good consistency in the threshold temperatures. The chip core area is 0.04 mm(2) and power consumption is 3.1 mu A at 3.3V power supply. The advantages of the temperature switch are low power consumption, the programmable threshold temperature and the controllable hysteresis.

Fabrication of low-cost and high-reflectivity bottom mirrors for Si-based micro-cavity devices

A novel and simple way to prepare high-reflectivity bottom mirrors for Si-based micro-cavity devices is reported. The bottom mirror was deposited in the hole, which was etched from the backside of the sample by ethylenediamine-pyrocatechol-water solution with the buried Sio, layer in the silicon-on-insulator substrate as the etching-stop layer. The high-reflectivity of the bottom mirror deposited in the hole and the narrow hill width at half maximum of the cavity formed by this method both indicate the successful preparation of the bottom mirror for Si-based micro-cavity devices.

Demonstration of low-cost Si-based tunable long-wavelength resonant-cavity-enhanced photodetectors

A simple process for fabricating low-cost Si-based continuously tunable long-wavelength resonant-cavity-enhanced (RCE) photodetectors has been investigated. High-contrast SiO2/Si(Deltan similar to2) was employed as mirrors to eliminate the need to grow thick epitaxial distributed Bragg reflectors. Such high-reflectivity SiO2/Si mirrors were deposited on the as-grown InGaAs epitaxy layers, and then were bonded to silicon substrates at a low temperature of 350 C without any special treatment on bonding surfaces, employing silicate gel as the bonding medium. The cost is thus decreased. A thermally tunable Si-based InGaAs RCE photodetector operating at 1.3-1.6 mum was obtained, with a quantum efficiency of about 44% at the resonant wavelength of 1476 nm and a tuning range of 14.5 nm. It demonstrates a great potential for industry processes. (C) 2005 American Institute of Physics.

Fabrication of low cost Si-based tunable high performance resonant cavity enhanced photodetectors

Low cost Si-based tunable InGaAs RCE photodetectors operating at 1.3similar to1.6 mum were fabricated using sol-gel bonding. A tuning range of 14.5 nm, a quantum efficiency of 44% at 1476 nm and a 3-dB bandwidth of 1.8 GHz were obtained.

High-efficiency and low-cost hybrid nanomaterial as enhancing electrocatalyst: Spongelike AWN core/shell nanomaterial with hollow cavity

A high-efficiency and low-cost spongelike Au/Pt core/shell electrocatalyst with hollow cavity has been facilely obtained via a simple two-step wet chemical process. Hollow gold nanospheres were first synthesized via a modified galvanic replacement reaction between Co nanoparticles in situ produced and HAUCl(4). The as-prepared gold hollow spheres were employed as seeds to further grow spongelike Pt shell. It is found that the surface of this hybrid nanomaterial owns many Pt nanospikes, which form a spongelike nanostructure. All experimental data including scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis-near-infrared spectroscopy have been employed to characterize the obtained Au/Pt hybrid nanomaterial. The rapid development of fuel cell has inspired us to investigate the electrocatalytic properties for dioxygen and methanol of this novel hybrid nanomaterial. Spongelike hybrid nanomaterial mentioned here exhibits much higher catalytic activity for dioxygen reduction and methanol oxidation than the common Pt electrode.

A simple and low-cost airlift photobioreactor for microalgal mass culture

A simple, low-cost, and efficient airlift photobioreactor for microalgal mass culture was designed and developed. The reactor was made of Plexiglas, and composed of three major parts: outer tube, draft tube and air duct. The fluid-dynamic characteristics of the airlift reactor were studied. The system proved to be well suited to the mass cultivation of a marine microalga, Chlorella sp. In batch culture, the biomass volumetric output rate of 0.21 g l(-1) d(-1) was obtained at the superficial gas velocity of 4 mm s(-1) in the draft tube.

A 5GHz low power WLAN transceiver SiGe RFIC for personal communication terminal applications

A low-cost low-power single chip WLAN 802.11a transceiver is designed for personal communication terminal and local multimedia data transmission. It has less than 130mA current dissipation, maximal 67dB gain and can be programmed to be 20dB minimal gain. The receiver system noise figure is 6.4dB in hige-gain mode.

Low threshold current density, low resistance oxide-confined VCSEL fabricated by a dielectric-free approach

We present the fabrication process and experimental results of 850-nm oxide-confined vertical cavity surface emitting lasers (VCSELs) fabricated by using dielectric-free approach. The threshold current of 0.4 mA, which corresponds to the threshold current density of 0.5 kA/cm(2), differential resistance of 76 Omega, and maximum output power of more than 5 mW are achieved for the dielectric-free VCSEL with a square oxide aperture size of 9 mu m at room temperature (RT). L-I-V characteristics of the dielectric-free VCSEL are compared with those of conventional VCSEL with the similar aperture size, which indicates the way to realize low-cost, low-power consumption VCSELs with extremely simple process. Preliminary study of the temperature-dependent L-I characteristics and modulation response of the dielectric-free VCSEL are also presented.

A COMPARATIVELY LOW-QUALITY SILICON MATERIAL IMPROVED FOR SOLAR-CELL FABRICATION

A comparatively low-quality silicon wafer (with a purity of almost-equal-to 99.9%) was adopted to form a silicon-on-defect-layer (SODL) structure featuring improved crystalline silicon near the defect layer (DL) by means of proton implantation and subsequent annealing. Thus, the SODL technique provides an opportunity to enable low-quality silicon wafers to be used for fabrication of low-cost solar cells.

A High-Efficiency Fiber-to-Waveguide Coupler with Low Polarization Dependence Using a Diluted Waveguide in InP Substrate with a 1.55μm Wavelength

We propose a fiber-to-waveguide coupler for side-illuminated p-i-n photodiodes to obtain high responsivity and low polarization dependence that is grown on InP substrate and is suitable for surface hybrid integration in low cost modules. The fiber-to-waveguide coupler is based on a diluted waveguide,which is composed of ten periods of undoped 120nm InP/80nm InGaAsP （1.05μm bandgap） multiple layers. Using the semi-vectorial three dimensional beam propagation method （BPM） with the central difference scheme,the coupling efficiency of fiber-to-waveguide under different conditions is simulated and studied,and the optimized conditions for fiber-to-waveguide coupling are obtained. For TE-like and TM-like modes,the calculated maximum coupling efficiency is higher than 94% and 92% ,respectively. The calculated polarization dependence is less than 0. ldB,showing good polarization independence.

用光学阵列传感器的机器人物体分类系统

本文介绍用光学阵列传感器的机器人物体分类系统。传感器直接安装在机器人的两个手指上。被抓物体的阴影通过光导纤维传到安放在“安全区”的光敏元件上。计算机识别物体的轮廓后命令机器人抓握物体,并把它运送到指定的地点从而达到物体分类的目的。

聚四氟乙烯烧结过程微机模糊群控系统

本文研究了用于聚四氟乙烯烧结过程实时控制的模糊群控微机系统的硬件及软件设计。系统的主要优点是低成本,高可靠性,其恒温区控温精度达±1.5℃。

The scientific project of the small satellite of china

The efforts involved in developing a small satellite for scientific purposes in China in recent years are introduced in the present paper. The project is arranged on a case to case principle depending upon requirements and financial support. The space technology of a satellite and rockets, which have been developed over a relatively longer period in China, have been transferred to the scientific research of small satellites for improvement of the quality requirements. The surplus payloads of the rocket and satellite are used as the payloads of the small satellite and scientific experiments at a low cost. As an example, the project of balloon satellites for atmospheric research was successfully completed in 1991. The experience of the project management is of great benefit for further organization and arrangement of other projects. Opportunities exist for surplus payloads to be used in the future, and a small satellite for magnetospheric research will be launched in 1993.