用于太阳能装置的柔性透明隔热材料

目前所使用的太阳能收集器是由既硬又重的材料制成的,这也就是为什么这样的太阳能收集器不能灵活移动的原因.因此,欧盟资助一项研究项目,用于开发新的太阳能收集系统,首先要柔韧和可移动,这样就可以在任意地方安置这类太阳能收集器.     

Seasonal Unit Root Tests Under Structural Breaks*

Abstract. In this paper, several seasonal unit root tests are analysed in the context of structural breaks at known time and a new break corrected test is suggested. We show that the widely used HEGY test, as well as an LM variant thereof, are asymptotically robust to seasonal mean shifts of finite magnitude. In finite samples, however, experiments reveal that such tests suffer from severe size distortions and power reductions when breaks are present. Hence, a new break corrected LM test is proposed to overcome this problem. Importantly, the correction for seasonal mean shifts bears no consequence on the limiting distributions, thereby maintaining the legitimacy of canonical critical values. Moreover, although this test assumes a breakpoint a priori, it is robust in terms of misspecification of the time of the break. This asymptotic property is well reproduced in finite samples. Based on a Monte‐Carlo study, our new test is compared with other procedures suggested in the literature and shown to hold superior finite sample properties.     

AudioMUD: a multiuser virtual environment for blind people.

A number of virtual environments have been developed during the last years. Among them there are some applications for blind people based on different type of audio, from simple sounds to 3-D audio. In this study, we pursued a different approach. We designed AudioMUD by using spoken text to describe the environment, navigation, and interaction. We have also introduced some collaborative features into the interaction between blind users. The core of a multiuser MUD game is a networked textual virtual environment. We developed AudioMUD by adding some collaborative features to the basic idea of a MUD and placed a simulated virtual environment inside the human body. This paper presents the design and usability evaluation of AudioMUD. Blind learners were motivated when interacted with AudioMUD and helped to improve the interaction through audio and interface design elements.     

The angio-architecture of normal, hypertrophic and denervated muscle. A study in the rat, using micro-angiography and the scanning electron microscope

The IQ's of Jamaican boys aged 6-10 were associated significantly with the presence or absence of severe malnutrition in infancy, with height at time of IQ testing, and with a measure of the boys' social background. A multiple correlation coefficient of 0.674 was obtained between IQ and the three factors. Social background contributed 0.294 of the variance, height 0.112, and severe malnutrition 0.049. The two extreme groups of boys, i.e., those malnourished, small at follow-up, and with unfavorable social backgrounds and those not malnourished, tall at follow-up, and with favorable social backgrounds had average IQ's of 49.4 and 74.9, respectively (from Table 5). Only two of the boys in the most advantaged group had IQ scores that overlapped with the most disadvantaged group. Boys with severe malnutrition in infancy, but who are tall at follow-up and have a favorable social background have an average IQ 11 points higher than boys who did not experience severe malnutrition, but who are short at follow-up and have a unfavorable social background. The difference in IQ between boys who did and did not experience severe malnutrition in infancy varies under different conditions of height and social background when those are held constant for both groups. Under the most favorable conditions of being tall and having an advantageous social history the average IQ of the malnourtished boys in only 2 points lower than those not malnourished. Unde the most unfavorable conditions of short stature and a disadvantageous social background the IQ of the malnourished boys is 9 points lower than those not malnourished (Table 6 and Fig. 1).     

Heats of reaction and kinetics of a thermoset polyester

The curing reaction of a thermoset polyester was investigated by using the isothermal and dynamic techniques of differential scanning calorimetry (DSC). The heats of reaction (at different curing temperatures) and a kinetic expression of the crosslinking reaction are presented and compared to the results of the previous studies. The proposed kinetic model can be utilized to obtain the rates of heat generation and the extent of cure at different cure temperatures and time. The overall activation energy of the curing reaction was calculated on the basis of experimental data as 17.0 kcal/mole and the overall reaction rate constant as 2.60 × 10⁹ exp (?17,000/RT) min^?1.     

Bioavailability of iron sensed by a phytoplanktonic Fe-bioreporter

This study describes a short-term (12 h) evaluation of iron (Fe) bioavailability to an Fe-dependent cyanobacterial bioreporter derived from Synechococcus PCC 7942. Several synthetic ligands with variable conditional stability constants for Fe(lll) (K* of 10(19.8) to 10(30.9)), in addition to several defined natural Fe-binding ligands and a fulvic acid of aquatic origin (Suwannee River), were used to elucidate the forms of Fe that are discerned by this phytoplanktonic microbe: Fe-HEBD (log conditional stability constant, K*, = 28.1, HEBD = N,N'-di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid monohydrochloride hydrate), Fe-HDFB (K* = 30.9, DFB = desferroxamine B), Fe-ferrichrome (K* = 23.2), Fe-DTPA (K* = 21.1, DTPA = diethylenetrinitrilopentaacetic acid), Fe-(8HQS)2 (K* = 20.4, 8HQS = 8-hydroxyquinoline-5-sulfonic acid), Fe-CDTA (K* = 19.8, CDTA = trans-1,2-cyclohexylenedinitrilotetraacetic acid), and Fe-EDTA (K* = 19.2). Iron bioavailability sensed by the bioreporter was related to diffusion limitation and activity of high-affinity transporters rather than by siderophore secretion. Iron complexed with a K* < 23.2 contributes to the bioavailable pool; bioavailability could be explained by disjunctive ligand exchange considerations and fully, partially, and nonbioavailable complexes could be distinguished according to their conditional stability constant. The use of Fe-bioreporters provides a relevant measurement of bioavailability to an important group of primary producers in freshwaters (cyanobacteria) and is thus a promising technique for understanding Fe cycling in aquatic systems.     

Speckle statistics in optical coherence tomography

The two previously reported calculations of the amplitude distribution of speckles in optical coherence tomography, each based on a different mathematical formulation, yield different results. We show that a modification of an initial assumption in one of the formulations leads to equivalent results.