复合材料为模具制造商创造机遇

在这个高科技操作运行的时代,先进的金属加工技术将能满足复合材料的生产需要。航宇工业和国防工业的业务正在迅猛发展,以及重塑军事能力在武器系统的发展,这为飞机制造业开创了有利局面。对这两个行业起着重要发展作用的一项技术就是复合材料,这一般是指碳纤维材料或玻璃纤维热固性和热塑性多材料层压板。这     

Factors affecting the correlation coefficient template matching algorithm with application to real-time 2-D coronary artery MR imaging

This paper characterizes factors affecting the accuracy of the correlation coefficient (CC) template matching algorithm, as applied to motion tracking from two-dimensional real-time coronary artery magnetic resonance images. The performance of this algorithm is analyzed in the presence of both random and systematic error. In the presence of random error, it is shown that a necessary and sufficient condition for accurate motion tracking is a large CC difference-to-noise ratio (CCDNR). The CCDNR itself is in turn affected by five factors: image and template size, image and template structure, and the magnitude of the noise. Techniques are introduced for manipulating some of these factors in order to increase the CCDNR for greater motion tracking accuracy. In the presence of superimposed systematic error it is shown that, while large CCDNR is necessary, it alone is not sufficient to ensure accurate motion tracking. Techniques are developed for improving motion tracking accuracy that minimize the effects of systematic error, while maintaining an adequate CCDNR level. The ability of these techniques to improve motion tracking accuracy is demonstrated both in phantoms and in coronary artery images.     

Compact 2.5 Gb/s Burst‐Mode Receiver with Optimum APD Gain for XG‐PON1 and GPON Applications

This letter presents a compact 2.5 Gb/s burst‐mode receiver using the first reported monolithic amplifier IC developed with 0.25 …m SiGe BiCMOS technology. With optimum avalanche photodiode gain, the receiver module can obtain a fast response, high sensitivity and wide dynamic range, satisfying the overhead timing and various power specifications for a 2.5 Gb/s next‐generation passive optical network (PON), as well as a legacy 1.25 Gb/s PON in the upstream.     

Angular MST‐Based Topology Control for Multi‐hop Wireless Ad Hoc Networks

This letter presents an angular minimum spanning tree (AMST) algorithm for topology control in multi‐hop wireless ad hoc networks. The AMST algorithm builds up an MST for every angular sector of a given degree around each node to determine optimal transmission power for connecting to its neighbors. We demonstrate that AMST preserves both local and network‐wide connectivity. It also improves robustness to link failure and mitigates transmission power waste.     

A survey on industrial communication networks

Industrial communication networks differ from other types of networks because these applications are responsible for the control and monitoring of a physical process. In this paper, we will summarise the requirements that users specify for these networks, present the state of art on field buses, factory and cell communication networks and indicate current research directions.     

Experimental performance of an adaptive digital linearized poweramplifier [for cellular telephony]

Amplification of linear modulation schemes, (which exhibit fluctuating envelopes), by high power amplifiers invariably leads to the generation of distortion and intermodulation products. Recent theoretical work has suggested that a complex gain predistorter may be employed to linearize a nonlinear power amplifier. The authors present experimental results demonstrating that a reduction in out-of-band spectra in excess of 20 dB may be achieved by employing digital feedback and a complex gain predistorter     

A Temperature‐Controllable Microelectrode and Its Application to Protein Immobilization

This letter presents a smart integrated microfluidic device which can be applied to actively immobilize proteins on demand. The active component in the device is a temperature‐controllable microelectrode array with a smart polymer film, poly(N‐isopropylacrylamide) (PNIPAAm) which can be thermally switched between hydrophilic and hydrophobic states. It is integrated into a micro hot diaphragm having an integrated micro heater and temperature sensors on a 2‐micrometer‐thick silicon oxide/silicon nitride/silicon oxide (O/N/O) template. Only 36 mW is required to heat the large template area of 2 mm×16 mm to 40°C within 1 second. To relay the stimulus‐response activity to the microelectrode surface, the interface is modified with a smart polymer. For a model biomolecular affinity test, an anti‐6‐(2, 4‐dinitrophenyl) aminohexanoic acid (DNP) antibody protein immobilization on the microelectrodes is demonstrated by fluorescence patterns.