数字标牌业务进入下一个发展阶段

由于全球经济衰退，数字标牌产业面临着一些挑战，实际情况是公司削减资本密集型项目，还是通过扩大方案的应用范围实现利润呢？     

Description and simulation of an active imaging technique utilizing two speckle fields: root reconstructors

Quasi-monochromatic light will form laser speckle upon reflection from a rough object. This laser speckle provides information about the shape of the illuminated object. Further information can be obtained if two colors of coherent light are used, provided that the colors are sufficiently close in wavelength that the interference is also measurable. It is shown that no more than two intensities of two speckle patterns and their interference are required to produce an unambiguous band-limited image of an object, to within an overall spatial translation of the image, in the absence of measurement errors and in the case where all roots of both fields and their complex conjugates are distinct. This result is proven with a root-matching technique, which treats the electric fields as polynomials in the pupil plane, the coefficients of which form the desired complex object. Several root-matching algorithms are developed and tested. These algorithms are generally slow and sensitive to noise. So motivated, several other techniques are applied to the problem, including phase retrieval, expectation maximization, and probability maximization in a sequel paper [J. Opt. Soc. Am. A 19, 458 (2002)]. The phase-retrieval and expectation-maximization techniques proved to be most effective for reconstructions of complex objects larger than 10 pixels across.     

Interactive effects of the electron acceptor sulphate and o-cresol on the methanogenic degradation of hexanoate

A three-stage continuous culture system was used to segregate the component microbial groups of a methanogenic hexanoate-degrading association enriched from anaerobic refuse. The inhibitory effects of o-cresol concentrations (2-20 mM) on the fermentative, acetogenic, sulphate-reducing and methanogenic bacteria were then assessed in the presence of either 1.4 or 3.5 mM sulphate in the influent medium. The sulphate-reducing bacteria (SRB) in the 1.4 mM sulphate-supplemented systems were the most sensitive to o-cresol, with 29.3 and 56.6% inhibition on supplementation with 4 and 6 mM o-cresol, respectively. With 3.5mM supplementation, inhibition was 4.5 and 19.4%, respectively. Methanogenesis was not inhibited by concentrations < 10 mM o-cresol, and complete inhibition was recorded only at concentrations > or = 10 mM. Both fermentation and acetogenesis were affected by inhibition of the electron sinks. The increase in influent sulphate concentration promoted electron flow to sulphidogenesis, as predicted on thermodynamic criteria, but did not affect the relative sensitivity of the different physiological groups.     

Designing emergent cooperation: a pursuit–evasion game case study

This research concerns a comparison of two neuroevolution approaches for the design of cooperative behavior in a group of simulated mobile robots. The first approach, termed single pool (SP), was characterized by robot neural controllers that were derived from a single genotype. The second approach, termed multiple pools (MP), was characterized by robot neural controllers that were derived from many different genotypes. The application domain implemented a pursuit–evasion game in which teams of robots of various sizes, termed predators, collectively worked to capture (immobilize) other robots, termed prey. The MP and SP approaches were tested, with and without lifetime learning, for the design of cooperative prey capture behavior within teams of predators. Results indicated that the MP approach was superior to the SP approach in terms of measures defined for prey-capture performance. Specifically, the MP approach facilitated behavioral specializations in the predator team facilitating emergent cooperative prey capture strategies that proved effective for the various team sizes tested.     

GaAsSb: a novel material for near infrared photodetectors on GaAs substrates

We have studied the molecular beam epitaxy (MBE) growth of GaAsSb on GaAs substrates. The optical properties and composition of GaAsSb layer strongly depend on the growth temperature, the Ga growth rate, and the As and Sb fluxes and their ratios. We also report on two GaAsSb-GaAs photodiode structures operating at 1.3 /spl mu/m. The peak quantum efficiency was 54% for the GaAsSb resonant-cavity-enhanced (RCE) p-i-n photodiode and 36% for the RCE GaAsSb avalanche photodiode (APD) with separate absorption, charge, and multiplication regions (SACM). At 90% of the breakdown, the dark current of the SACM APD was 5 nA. The GaAsSb SACM APD also exhibited very low multiplication noise and k/sub eff/ was approximately 0.1, which is the lowest ever reported for APDs operating at 1.3 /spl mu/m.     

Synthesis of porphyrin-PPV copolymers for application in LEDs

A new series of soluble porphyrin-containing copolymers have been synthesized via the Gilch methodology [1], for use in light-emitting devices (LEDs). These materials consist of random copolymers of 2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene (MEH-PPV) and a porphyrin-substituted phenylene vinylene. Low concentrations of porphyrin monomers were used in order to improve solubility, and help prevent aggregation (and consequent fluorescence quenching) of the porphyrin units. Emission is red-shifted from that expected in dialkoxy-PPVs such as MEH-PPV owing to an efficient exciton transfer to the fluorescent porphyrin unit.     

The feasibility and outcome of clinic plus Internet delivery of cognitive-behavior therapy for childhood anxiety.

Seventy-two clinically anxious children, aged 7 to 14 years, were randomly allocated to clinic-based, cognitive-behavior therapy, the same treatment partially delivered via the Internet, or a wait-list control (WL). Children in the clinic and clinic-plus-Internet conditions showed significantly greater reductions in anxiety from pre- to posttreatment and were more likely to be free of their anxiety diagnoses, compared with the WL group. Improvements were maintained at 12-month follow-up for both therapy conditions, with minimal difference in outcomes between interventions. The Internet treatment content was highly acceptable to families, with minimal dropout and a high level of therapy compliance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Congenital abnormalities in Brazilian children associated with misoprostol misuse in first trimester of pregnancy

BACKGROUND: Misoprostol is commonly used to induce abortion in Brazil, and in other countries in South and Central America where abortions are illegal. However, misoprostol is not very effective in inducing abortions, and exposure to the drug in utero can cause abnormalities in the fetus. We aimed to define the common phenotypical effects of exposure to the drug. METHODS: We studied 42 infants from S?o Paulo, Brazil, who were exposed to misoprostol during the first 3 months of gestation, and then born with congenital abnormalities. We interviewed each of the infants' mothers to find out about misoprostol exposure and dosage. Each infant was physically examined by a geneticist or a neuropaediatrician. FINDINGS: 17 of the infants had equinovarus with cranial-nerve defects. Ten children had equinovarus as part of more extensive arthrogryposis. The most distinctive phenotypes were arthrogryposis confined to the legs (five cases) and terminal transverse-limb defects (nine cases) with or without Mobius sequence. The most common dose of misoprostol taken was 800 microg (range 200-16000 microg). INTERPRETATION: Deformities attributed to vascular disruption were found in these children. We suggest that the uterine contractions induced by misoprostol cause vascular disruption in the fetus, including brain-stem ischaemia. Information on the effects of taking misoprostol during pregnancy should be made more widely available, to dissuade women from misusing the drug.     

Through the looking glass darkly? When self-doubts turn into relationship insecurities.

The authors argue that individuals regulate perceptions of their relationships in a self-protective way, finding virtue in their partners only when they feel confident that their partners also see virtues in them. In 4 experiments, the authors posed an acute threat to low and high self-esteem individuals' feelings of self-worth (e.g., guilt about a transgression, fears of being inconsiderate or intellectually inept). They then collected measures of confidence in the partner's positive regard and acceptance (i.e., reflected appraisals) and perceptions of the partner. The results revealed that low self-esteem individuals reacted to self-doubt with heightened doubts about their partners' regard, which then tarnished impressions of their partners. In contrast, high self-esteem individuals reacted to self-doubts by becoming more convinced of their partners' continued acceptance, using their relationships as a resource for self-affirmation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)