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61.
Abstract— The flexoelectro‐optic effect provides a fast‐switching mechanism (0.01–0.1 msec), suitable for use in field‐sequential‐color full‐motion‐video displays. An in‐plane electric field is applied to a short‐pitch chiral nematic liquid crystal aligned in the uniform standing helix (or Grandjean) texture. The switching mechanism is experimentally demonstrated in a single‐pixel test cell, and the display performance is investigated as a function of device parameters. A contrast ratio of 2000:1 is predicted.  相似文献   
62.
Magnetic materials used in cored microinductors to supersede ferrite in the 0.5-10 MHz frequency range are investigated in this article. The performance of electrodeposited nickel–iron, cobalt–iron–copper alloys and the commercial alloy Vitrovac 6025 have been assessed through their inclusion within a custom-made solenoid microinductor. Although the present inductor achieves 77% power efficiency at 500 KHz for 24.7 W/cm3 power density, an optimized process predicts a power efficiency of 97% for 30.83 W/cm3 power density. The main issues regarding microinductor design and performance are discussed.  相似文献   
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Industries in the US continue to lose ground in international competition. If IS is to help change that trend, it will have to become more creative. Creativity improvement programs are being introduced in other areas of the company— now is the time for IS organizations to follow suit.  相似文献   
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A group of public health scientists from the United States and The Netherlands met at a Bicentennial Round Table Conference December 1-2, 1982, to discuss the latest developments in immunization against infectious diseases, focusing on pertussis, poliomyelitis, measles, and rubella. The major differences in immunization practices in the two countries are: (a) In The Netherlands, inactivated polio vaccine is used exclusively; in the United States, the oral polio vaccine is used. Polio-myelitis has virtually disappeared from both countries. (b) In The Netherlands, the pertussis component of DTP (diphtheria, tetanus, pertussis) is not given to children over the age of 1 year, whereas in the United States, it is given to children up to their seventh birthday. (c) Rubella vaccine is given only to girls at ages 11-12 years in The Netherlands, but to all children at ages 12-15 months in the United States. (d) Mumps vaccine is not administered to children in The Netherlands, but in the United States it is given routinely to children at 12-15 months (in combination with measles and rubella vaccine). The participants concluded that both the United States and The Netherlands have effective immunization programs that have significantly reduced the impact of these diseases.  相似文献   
67.
Abstract.  This paper presents a commitment transformation framework for analysing the change in actors' commitment during the transition from escalation to de-escalation in information technology projects. De-escalation is potentially a more important issue than escalation because de-escalation provides remedies for the ills of escalation. Therefore, it is important to understand how stakeholders may bias facts in the direction of previously accepted beliefs and thus prevent an organization from de-escalating. Here, we adopt Lewin's change theory to examine the commitment transformation during the transition from escalation to de-escalation of an e-government project in a local council in the United Kingdom. By conceiving actors' commitment transformation as an 'unfreezing–changing–refreezing' process, researchers may develop a deeper understanding of how actors may give up previous failing course of action and accept an alternative course of action. Practitioners can also utilize the framework in post-mortem analyses of projects which have faced escalation to devise useful de-escalation strategies for future project development. 1  相似文献   
68.
A technique for demodulating a simple a.c. biased magnetoresistor's signal is presented. The application highlighted is the measurement of power-line frequency magnetic fields for the study of their effects on human health. The circuit enables very low magnetic fields to be resolved whilst maintaining a wide d.c. magnetic-field dynamic range with the aid of d.c. feedback in both hard and easy axes of the sensor. The easy-axis feedback field maintains constant sensitivity even under the influence of large easy-axis external fields. Long-term stability is typically better than 20 nT.  相似文献   
69.
This paper presents the use of micro-particle imaging velocimetry (micro-PIV) to analyse fluid flow and hence ion replenishment in PCB micro-via during the electroplating process. The cross section of a PCB via is fabricated in PMMA to allow optical access to the sample. Fluid flow within two 1:1 aspect ratio blind micro-vias, one with straight side walls and the other with tapered side walls were compared. Flow is also analysed in a 1:1 aspect ratio through via. Flow rates measured using micro-PIV are used to validate simulated flow models. The results show that there are increased flow rates within the blind via with tapered side walls. This goes some way to explaining the improved electroplating results obtained in industry when tapered vias are used. Initial experimental results using megasonic streaming to remove bubbles from blind micro-via and promote ion transportation within high aspect ratio PCB micro-via to enhance electrodeposition are also reported.  相似文献   
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