科帕卡格拉纳建筑 奥地利维亚纳

正科帕卡格拉纳位于新多瑙河12.5公里处,毗邻Reichsbrücke大桥。出于同旧有设计保持协调性考虑,力求能让大楼融入当地环境,迎合自身功能性需要,GERNER GERNER PLUS团队充分考虑现有周边环境,对大楼重新规划设计。新的设计突显建筑的特殊性和重要性,面向河流的立面是科帕卡格拉纳大楼最重要的部分,所以设计的重点也放在了这里。现有的城市中轴线是一个参照物,为了视觉上和氛围上形成一体化城市的感     

High-precision high-yield laser source using DFB array

We present high-yield efficient distributed-feedback lasers with excellent wavelength control. An array of 12 lasers with highly reflecting/antireflecting facets is fabricated on a single chip with precisely controlled variations in the grating period or phase relative to the facets. The stripe that best meets requirements is selected for bonding. From 200 unscreened chips, 93% contained lasers that achieved the specified power of 25 mW at 175 mA, 55/spl deg/C, and 41% achieved a /spl plusmn/0.1-nm wavelength tolerance at 25 mW, 55/spl deg/C. This low-cost high-precision device requires little thermal tuning for wavelength-division-multiplexed applications and reduces the power consumption of the transmitter.     

Long-range mapping and construction of a YAC contig within the cat eye syndrome critical region

Cat eye syndrome (CES) is typically associated with a supernumerary bisatellited marker chromosome derived from human chromosome 22pter to 22q11.2. The region of 22q duplicated in the typical CES marker chromosome extends between the centromere and locus D22S36. We have constructed a long-range restriction map of this region using pulsed-field gel electrophoresis and probes to 10 loci (11 probes). The map covers -3.6 Mb. We have also used 15 loci to construct a yeast artificial chromosome contig, which encompasses about half of the region critical to the production of the CES phenotype (centromere to D22S57). Thus, the CES critical region has been mapped and a substantial portion of it cloned in preparation for the isolation of genes in this region.     

Guides d’ondes enfouis dans des superréseaux GaAs-AIGaAs créés par interdiffusion induite par des impuretés

Heterostructures comprised of Al_xGa_1?xAs-Al_yGa_1?yAs As superlattices or quantum wells are compositionally stable up to very high temperatures but may become unstable with the introduction of particular impurities. The resulting layer interdiffusion leads to a compositionally averaged material. Since the introduction of impurities can be controlled by standard photolithographic masking techniques, the material properties can be modified in unmasked region. The disordered region has a wider bandgap and a lower index of refraction. This property has been used to fabricate delineated buried waveguides which exhibit very low propagation losses. Experimental results show that the index step between the layered and disordered region is at least 2.3 %. While not large in magnitude, this index difference is sufficient to allow complex waveguide structures to be made in the same materials used for other high performances opto-electronic devices.     

Birthweight and blood pressure among children in Harare, Zimbabwe

AIM: To determine whether poor uterine growth may be associated with increased blood pressure and subsequent hypertension in adulthood. METHODS: A retrospective cohort study of 756 schoolchildren (mean age 6.5 years) was carried out in six low income areas in Harare city, Zimbabwe. Indices of intrauterine growth and blood pressure were assessed. RESULTS: Adjusted for current weight, the children's systolic blood pressure was inversely related to their birthweight; for each decreasing kg of birthweight, systolic blood pressure rose by 1.73 mm Hg (95% CI; 0.181 to 3.28). After adjustment for current weight, systolic blood pressure was also inversely associated with occipito-frontal circumference, but not with birth length or gestational age. Diastolic blood pressure was not associated with any of the intrauterine indices. CONCLUSION: Fetal size may be inversely related to systolic blood pressure in childhood in an African population.     

Pre- and poststimulus activation of response channels: A psychophysiological analysis.

To examine mechanisms of response activation, we asked subjects to respond differentially to the central letter of one of four arrays—{hhhhh}, {sshss}, {sssss}, and {hhshh}—and measured event-related brain potentials (ERPs) and electromyographic activity (EMG). For very fast responses, accuracy was at chance level for all arrays, suggesting that subjects were guessing. For intermediate latency responses, accuracy was above chance if the noise was compatible with the targets and below chance if it was incompatible, suggesting that these responses were based on partial stimulus analysis. For slow responses, accuracy was above chance for all arrays, suggesting that these responses were based on complete stimulus analysis. The occurrence and accuracy of fast responses could be predicted by examining motor potentials preceding the presentation of the array. Measures of the motor potentials in the period following the presentation of the array suggested that partial analysis of stimulus information could activate responses and that the level of response activation at the time of the EMG response was constant for trials with different response latencies. The data are discussed in terms of a response channel conception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

RETRPROV A system that looks for axioms

 In this paper we shall describe a formal system which enables us to prove theorems within propositional calculus, logic of quantifiers and first order theories, including theorems containing programs. Its main feature relies on generating an additional set of assumptions needed to prove a considered formula. Thus we are able to consider expressions which can become theorems by looking for a special set of assumptions (axioms) and then adding it to the standard set of axioms. Using this system the correctness and equivalence of programs can be determined. In the end we present some experimental results. Received 25 February 1993/11 September 1995     

Complementary self-aligned laser by metalorganic chemical vapour deposition

A complementary two-step MOCVD growth technique for the self-aligned laser is described which eliminates any possible difficulty associated with regrowth on a high composition AlGaAs layer by placing the regrowth interface outside the stripe region. Single-longitudinal-mode operation with stable near and far-field patterns has been obtained to more than twice the laser threshold current.     

Restraining of calcium contamination in near‐net shape alumina ceramics during slip casting

The traditional method for shaping ceramics is by slip casting on gypsum molds; however, its application for near‐net shaping of ceramic components is limited due to contamination by calcium ions. The focus of this study is the modification of the mold to limit Ca²⁺ contamination and to maintain favorable sucking properties. Cement was added to a standard gypsum mold to suppress its erosion, and a decrease in the sucking rate was observed due to its reduced macroporosity. The highest values of green densities were obtained at gypsum/cement weight ratios of 90/10 and 70/30. The microstructure analysis showed that alumina blocks prepared from the molds containing higher quantities of cement (30 or 50 wt%) were resistant to abnormal grain growth caused by Ca²⁺ contamination from the gypsum. The gypsum/cement mixtures for making molds for slip casting significantly limit mold erosion due to a lower sucking rate and abnormal grain growth of the slip cast samples because of the decreased diffusivity of Ca²⁺ ions. Therefore, the present modification of the mold renders the slip casting method more suitable for the near‐net shaping of ceramics.     

Graphene Actively Mode‐Locked Lasers

Actively mode‐locked lasers offer varying degrees of flexibility for a wider range of applications than their passively modulated counterparts, due to their capability for electrically controlled ultrahigh repetition rate operation. Graphene based electrooptic modulators with unique advantages of broad operation bandwidth and ultrafast speed are suitable for light modulation in various optoelectronic applications. Here, an actively mode‐locked laser with a graphene based electrooptic modulator is reported for the first time. The active mode‐locking technique combined together with the intracavity nonlinear pulse shortening effect allows the generation of transform‐limited 1.44 ps pulses with pulse energy of 844 pJ. The electrically controlled repetition rate of generated pulses, a key performance advantage of active mode‐locking, is also demonstrated. These results provide a practical and effective approach for actively mode‐locked lasers with broad operation bandwidth and compact footprint, which contributes a new way for applications of two‐dimensional (2D) layered materials in ultrafast lasers.