Fluidic actuation by electrorheological microdevices

Electrorheological microdevices with planar and cylindrical geometry have been developed for control of fluidic microactuators. The devices consist of capacitor elements of 50 μm gap size, which confine a flow channel of 10–20 mm length. A homogeneous electrorheological fluid (ERF) is used for operation of the devices displaying a viscosity change of about 25 for a voltage of 500 V at a pressure difference of 2000 hPa. The maximum control power is 0.65 mW. Switching times are in the order of 50 ms. The microdevices have been used to control the motion of a micropiston with 1 mm stroke fabricated by the LIGA technology.     

Blood Velocity Measurement by Fiber Optic Laser Doppler Anemometry

Laser Doppler anemometry has been used to measure blood velocities by using a fine fiber optic probe both to deliver laser light into the blood and to receive reflected light from red blood cells at the tip of the probe. In vitro, with the probe aligned in the direction of flow, nonlinear calibration is possible to velocities of 15 cm/s in a 3 mm diameter vessel. When the probe is aligned against the flow, measurement of velocity is linear to at least 1 m/s. In vivo recordings of coronary and aortic blood velocity are produced by performing a fast Fourier transform (FET) in real time.     

Fundamental investigation of roll bond heat pipe as heat spreaderplate for notebook computers

A roll bond heat pipe (RBHP) is very promising in the cooling of electronic equipment such as notebook computers. This study presents prediction data on maximum capillary limit obtained for the RBHP with 7.8 mm wide flow channel. Further, experimental study has been conducted to show the difference between the highest and lowest temperatures on the RBHP. These data determine the optimum working fluid charge volume and number of capillary loops for the RBHP     

Thermal diffusion probe and instrument system for tissue blood flowmeasurements: validation in phantoms and in vivo organs

A minimally invasive probe and instrument system for real-time measurements of temperature, thermal conductivity and tissue blood flow has been designed for research and clinical use. The essence of the probe is a thermistor, located at the tip of catheters or glass and steel needles, and operating in transient self-heated mode at constant temperature increment. Thermal conductivity and tissue blood flow are determined by use of a coupled tissue-probe thermal model. The effects of temporal baseline temperature shifts are minimized by a novel, automatic, analog compensation circuit. Very short heating periods (3 s) and cooling periods (12 s) provided near-continuous measurements (4/min). Calibration experiments performed in media of known thermal conductivity exhibit a linear response with respect to thermal conductivity. In vitro experiments performed in isolated perfused dog liver preparations are presented to evaluate this instrument system. In vivo experiments performed in cat brain, dog liver, and human tumor demonstrate the ability of this instrument system to perform physiologically valid measurements (comparison inter-subjects and intra-subjects). The minimally invasive probes (0.8 mm OD) are capable of long term measurements (several months), with minimal tissue reactions (0.3 mm around the probe)     

φ2mm微马达驱动旋转式微泵

在生物医学、化学液体的流量检测与分析及固态元器件冷却等领域中,均需要流量的精细控制和检测系统。在这类流量精细控制和检测系统中,微小型泵是一个基本元件。作者利用上海交通大学研制成功的、由微细加工工艺制备的、直径为2mm的电磁型微马达作驱动源,并配以电火花加工工艺制备的蜗壳和Ti合金叶轮制成旋转式微泵。微泵的外形尺寸为φ4．5×6．5mm,最大流量可达12ml／min,流量可根据马达转速进行调节。     

基于激光PIV技术的XFD浮选机流场特征分析

采用激光粒子成像测速(PIV,particle imaging velocimetry)技术对XFD-1.5L浮选机流场进行测定,揭示了XFD浮选机流场特征。在浮选机转速为1 000r/min的条件下,对10-10、20-20和30-30等3个平面进行了探测。实验结果表明,XFD浮选机主要特征为:流体在主槽与副槽之间循环;浮选机主槽可以分为3个区域,Y=0~25mm区间以水平旋转流为主,Y=25~120mm区间以上升流为主,Y=120~145mm区间以流向副槽的水平流为主,分别对应于浮选理论中的搅拌区、分离区和泡沫区;浮选机流场设计合理,有利于矿物的分选。     

Nondestructive high-resolution microwave imaging of biomaterials and biological tissues

A high-Q near-field probe based on the 2D microstrip line geometry using defected ground structure (DGS) has been proposed and experimentally evaluated for nondestructive characterization and high-resolution imaging of biomaterials and biological tissues. The unique specifications of the probe are as follows; small size, simple fabrication, non-contact with a sample, excellent de-coupling from surroundings and high microwave power is directly coupled into the tissues. Experimental results show that the probe is able to detect the microwave characteristics of thin lossy biomaterials containing water. High resolution microwave images of leaves with different water content have been obtained with amplitude contrast of about 40–50 dB and spatial resolution of about λ/40. Also, a measurement scenario for detection of lipomas with different sizes has been investigated. Results show that the proposed probe can detect the lipoma of a size larger than 5 mm. Finally, an artificial model to detect skin cancer at the early stage is developed using layers of raw chicken skin. Measurement results show that the probe could accurately detect malignant tumor with at least 15 dB magnitude and more than 100° phase contrast from the healthy skin and with about 8 dB contrast from the benign lesions of the same size.     

Variable-velocity MHD induction generator with rotating-machine internal electrical efficiency

A traveling-wave, MHD induction generator with varying fluid velocity between inlet and exit can have the same internal electrical efficiency as a rotating induction generator. The fraction of electric retarding work converted to electric output at each station in the flow channel is (1 + s)^-1, where s is the local slip (U - Us)/Us, between the velocity of the fluid U and the velocity of the zero crossing of the magnetic field wave Us. To produce the rotating-machine efficiency, the product of magnetic field amplitude, wave velocity, and flow channel width is held constant from inlet to exit. The local slip can be freely chosen for maximum electric output from the fluid in the presence of friction, and the inlet magnetic field can be selected for maximum output after winding and end losses. An efficiency of 0.63 is found possible with a 325-kW lithium generator.     

基于GRIN透镜的内窥OCT探头设计

提出一种用于在体活检的光谱 OCT 内窥探头的设计方案,能够实现对生物组织器官深度信息的在体内快速动态实时扫描成像,在临床医学领域具有广阔的应用前景。文中对探头的设计进行了理论分析,对探头的加工和测试进行了系统的阐述。针对传统的 GRIN 探头设计,本文探头的设计提高了光学质量和机械健壮性。对于 OCT 探头的成像质量依赖于单模光纤和 GRIN 透镜之间的距离（玻璃垫片长度）,进行了建模和验证。实验得出将玻璃垫片长度控制在0．2 mm 左右,探头可以达到2 cm 左右的工作距离,工作距离范围内探头的远场光束发散角为0．0175°。     

Experimental study of diagonal conducting wall generators using solid propellants

The work reported here is the result of using a special solid fuel developed as a working fluid for MHD generators by Hercules Inc. Conductivity measurements of the combustion products were made using the electrodes of the Hall channel as floating potential probes. The experimentally determined values of the average conductivity for this type of propellant were found to be in the range between 40 and 50 mho/m. Generator experiments were performed with two different types of channels operating as a Hall generator and as a 45° diagonal conducting wall generator. The generator power output was found to be 3 to 4 times higher than that achieved by even higher flow rates using conventional RP1 and gaseous oxygen for the same generator channel and magnetic field conditions. However, the power increase was insignificant for the Hall generator. The generators operated with relatively little effect observed when coatings of aluminum oxide and other chemicals from the fuel covered the interior of the channel.     

Miniature ultra-broad-band voltage probe

A miniature voltage probe giving a good response over 2?18 GHz is described. It is constructed from standard OSSM line of approximately 2 mm diameter, and has been used in a miniature l.s.a. circuit for measuring Gunn-diode l.s.a. waveforms with harmonics up to 14 GHz.     

A periodontal probe with automated cemento--enamel junction detection-design and clinical trials.

An automated periodontal probe has been developed to measure pocket depth and attachment loss in a single measurement under controlled force conditions. A natural anatomic landmark, the cemento-enamel junction (CEJ), is used as a reference for attachment level measurements. The CEJ is detected automatically by immediate digital postprocessing of simultaneous measurements of probe tip acceleration and displacement during probing. Clinical trials in the beagle dog model for naturally occurring periodontitis have shown that the automated probe, when used with 35 g probing force, has a repeatability of 0.16 mm and a bias of 0.09 mm. These results indicate that the automated periodontal probe is capable of attachment level measurements with a high degree of repeatability and validity.     

Fast-response silicon flow sensor with an on-chip fluid temperature sensing element

A new silicon flow sensor with a robust thermal isolation structure has been developed. The thermal isolation structure is mainly made of a 20-µm-thick oxidized porous silicon membrane. This thermal isolation structure makes it possible for the sensor to have a fast-response characteristic and an on-chip fluid temperature sensing element design. The sensor can be used in liquid flow as well as gas flow. Its operation is based on heat transfer from the heated sensor to a moving fluid. It has two platinum thin-film resistors, a heating element, and a fluid temperature sensing element on the chip. The sensing element is thermally isolated from the heating element. The external circuit of the sensor maintains a constant temperature difference between the heating element and the fluid. The sensor chip characteristics were evaluated theoretically by heat transfer analysis during the chip design. Measurements were made for oil flow velocity of 0-30 cm/s and air flow velocity of 0-14 m/s. Response time was below 100 ms, and a compensated output for fluid temperature change was obtained.     

A periodontal probe with automated cemento-enamel detection-designand clinical trials

An automated periodontal probe has been developed to measure pocket depth and attachment loss in a single measurement under controlled force conditions. A natural anatomic landmark, the cemento-enamel junction (CEJ), is used as a reference for attachment-level measurements. The CEJ is detected automatically by immediate digital postprocessing of simultaneous measurements of probe-tip acceleration and displacement during probing. Clinical trials in the beagle dog model for naturally occurring periodontitis have shown that the automated probe, when used with 35-g probing force, has a repeatability of 0.13 mm and a bias of 0.09 mm, indicating that the automated periodontal probe is capable of attachment-level measurements with a high degree of repeatability and validity     

Detailed characterization and analysis of the breakdown voltage infully depleted SOI n-MOSFET's

The breakdown voltage in fully depleted SOI n-MOSFET's has been studied over a wide range of film thicknesses, channel dopings, and channel lengths. In lightly-doped films, the breakdown voltage roll-off at shorter channel lengths becomes much less severe as the film thickness is reduced. This is a result of improved resistance to punchthrough and DIBL effects in thinner SOI. Consequently, at channel lengths below about 0.8 μm, ultrathin (50 nm) SOI can provide better breakdown voltages than thicker films. At heavier doping levels the punchthrough and DIBL are suppressed, and there is little dependence of breakdown voltage on film thickness. Two-dimensional simulations have been used to investigate the breakdown behavior in these devices. It is found that the drain-induced barrier lowering affects the breakdown voltage both directly, via punchthrough, and indirectly through its effect on the current flow and hole generation in the high-field regions     

CMOS chip for invasive ultrasound imaging

A very small transmit/receiver chip has been developed for use in an arterial ultrasonic imaging system. In this technique, a solid-state ultrasonic imaging head placed within a small medical catheter is used to provide high quality 360° images of arteries as small as 2 mm in diameter. Novel design and packaging techniques have been used to allow four easily testable 0.86 mm×1.65 mm mixed-signal CMOS die to be placed on a multichip carrier within this 1.83 mm diameter imaging probe. Each chip contains interface circuitry for sixteen transducers including 20 MHz transmit pulsers and receive current amplifiers with approximately 1.3 pA/rt-Hz equivalent input noise performance. The techniques described here are generally applicable to any probe or device with extreme size and performance requirements     

Damage-Free Cryogenic Aerosol Clean Processes

Cryogenic aerosol clean processes have been successful for cleaning of blanket films and robust device structures. As the line width becomes smaller and aspect ratios (ARs) become higher, they have either been eliminated or used with caution due to line damage. Theoretical line damage modeling indicates that collision induced stress in line structures is a function of the AR of line cross section. Theoretical analysis also shows that smaller and lighter cryogenic aerosol crystal is desired to avoid line damage. Nitrogen cryogenic aerosol processes have been evaluated for damage-free cleaning on 90 and 65 nm technologies at the IBM 300 mm manufacturing line. Process results on the 90 nm technology at the post spacer nitride deposition clean have shown no damage and particle removal efficiency (PRE) greater than 92%. Implementation of the same nitrogen only aerosol process at the post cobalt silicide probe test clean on 90 nm high AR gate structures has shown significant improvement over the previous process of record argon/nitrogen-based aerosol. Evaluation at the post nickel silicide probe test clean on 65 nm device technology with low AR gate structures has shown the process is damage-free with particle removal efficiency greater than 95%. This nitrogen only aerosol process has been implemented in the 65 nm technology flow and has been proven to be damage-free in volume manufacturing     

Ion-implanted high microwave power indium phosphide transistors

Encapsulated rapid thermal annealing (RTA) has been used in the fabrication of indium phosphide (InP) power metal-insulator-semiconductor field-effect transistors (MISFETs) with ion-implanted source, drain, and active channel regions. The MISFETs had a gate length of 1.4 μm. Six to ten gate fingers per device, with individual gate finger widths of 100 or 125 μm, were used to make MISFETs with total gate widths of 0.75, 0.8, or 1 mm. The source and drain contact regions and the channel region of the MISFETs were fabricated using silicon implants in semi-insulating InP at energies from 60 to 360 keV with doses from 1×10¹² to 5.6×10¹⁴ cm^-2. The implants were activated using RTA at 700°C for 30 s in N₂ or H₂ ambients using a silicon nitride encapsulant. The high-power, high-efficiency MISFETs were characterized at 9.7 GHz, and the output microwave power density for the RTA conditions used was as high as 2.4 W/mm. For a 1-W input at 9.7 GHz gains up to 3.7 dB were observed, with an associated power-added efficiency of 29%. The output power density was 70% greater than that reported for GaAs MESFETs     

Surface-acoustic-wave guidance produced by ion implantation in quartz

An increase in the surface-acoustic-wave velocity is produced by ion implantation in quartz (y-cut, x-propagating). A 2.5% relative-velocity increase has been measured at 395 MHz, with 100 keV Li+ ions, the flux being 1016 ions/cm2. Slot acoustic waveguides have been realised at about 100 and 400 MHz by these techniques. Horns were used for matching the launched acoustic beams to the guides. An optical probe has been employed for investigating the spatial distribution of the acoustic power. The 100 MHz guide is 148 ?m wide. The guided-power profile along a section of the guide has been measured. The 6 dB beamwidth is about 230 ?m. The 400 MHz guide is 18 ?m wide, and the propagation loss is about 0.75 dB/?s.     

Practical Channel Transition for Near-VOD Services

Periodic broadcasting is known as an efficient technique to support near Video-on-Demand services for delivering popular videos, since it can reduce the bandwidth requirement for transmitting streaming video to simultaneous viewers. The channel transition problem is an issue to be concerned about the variability of popularity of video. In this paper, we present a novel channel transition scheme based on the fast broadcasting. In most conditions, our proposed scheme has less bandwidth waste than the existing SFB scheme. In addition, no extra startup latency and client buffer are needed in our scheme.