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51.
The applicability of heavy atom–induced room temperature phosphorescence (HAI-RTP) in real samples is demonstrated in this work. In this methodology only two reagents, potassium iodide as heavy atom salt and sodium sulfite as oxygen scavenger, were used to obtain the phosphorescent signal of carbazole in solution while anthracene did not show phosphorescence under these experimental conditions. In this study a new simple, rapid, and selective phosphorimetric method is proposed, using HAI-RTP methodology for the determination of carbazole in high-purity anthracene. The phosphorescence intensity was measured at 438 nm with excitation at 290 nm. Phosphorescence was fully developed instantly. A linear concentration range between 0 and 250 ng/mL?1 with a detection limit of 1.05 ng/mL?1 (10.5 ng of CBZ in 600 ng of anthracene), an analytical sensitivity of 1.7 ng/mL?1, and standard deviation of 0.71% at 150 ng/mL?1 concentration level was obtained. The method has been successfully applied to the analysis of carbazole in spiked anthracene samples.  相似文献   
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The main purpose of the present study was to examine implicit and explicit self-esteem (SE) in patients with persecutory delusions. In samples of paranoid patients, depressed patients, and healthy controls, implicit SE was assessed using the experimental go/no-go association task, whereas explicit SE was measured using 2 self-reporting questionnaires: the self-worth subscale of the World Assumption Scale (Janoff-Bulman, 1989) and the self-acceptance subscale of the Scales of Psychological Well-Being (Ryff & Keyes, 1995). Our analysis revealed that depressed patients showed lower explicit SE than did paranoid and healthy control participants. However, participants with persecutory delusions had significantly lower implicit SE scores than did healthy controls. We interpret the discrepancies observed between overt and covert measures in the paranoid group as psychological defense mechanisms. The present study stresses the clinical and theoretical importance of the use of implicit measures in psychopathology. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
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We sequenced the nuclear small subunit of ribosomal DNA (SSU rDNA) from seven species within the insect-pathogenic order Entomophthorales. These sequences were aligned with other published SSU rDNA sequences and phylogenies were inferred using phenetic and cladistic methods. Based on three different phylogenetic methods the Entomophthorales (excluding Basidiobolus ranarum) is monophyletic; B. ranarum was more closely related to chytrids from Chytridiales and Neocallimasticales than to Entomophthorales, as was proposed by Nagahama et al. (Mycologia 87: 203-209, 1995). Nuclear characters (large nuclei containing conspicuous condensed chromatin and lack of a prominent nucleolus) were of predictive value for the monophyly of the family Entomophthoraceae. Conidial characters separate the Entomophthoraceae, which only includes obligate pathogens, into at least two lineages: one lineage with uninucleate conidia and another with multinucleate conidia. The two species of Conidiobolus studied were paraphyletic in our analyses and only distantly related to each other. This information may prove to be important in the use of these fungi as biocontrol agents.  相似文献   
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The problem of achieving sustainable groundwater management in areas of over-exploitation is examined by using the upper Guadiana basin in central Spain as an example. Here, since the early 1970s, high rates of abstraction to provide water for irrigation have lowered the water table by up to 50 m, causing the main rivers to run dry and an internationally renowned wetland to become desiccated. Conflict between farmers, regulators and conservationists has created a difficult problem that legal action, subsidies and engineering solutions have so far failed to combat. Faced with conflicting demands, it is suggested that integrated catchment management provides the best way forward. The various issues that need to be addressed with this type of management system are outlined.  相似文献   
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This work investigates the formation of photoluminescence (PL) centres in high-transmission glasses (HTG) doped with Cu2O and their capability to transform the solar spectrum by absorption/emission via upconversion, downconversion and Stokes-shifted PL into a more efficient spectrum for photovoltaic applications. Both the green PL Cu+ and the non-PL Cu2+ centres are formed in HTG, although their relative concentration depends on the thermal treatment and the presence of other codopants. Given that the absorption spectrum of Cu+ lies around the HTG band gap, measurement of the absorption coefficient α(λ) for these absorption bands is not easy due to corrections between the reflection coefficient and chromatic dispersion. We present a procedure, named two-thickness method, to extract the actual absorption coefficient for the spectrum of each formed centre. In addition it provides the relative Cu+/Cu2+ concentration as well as their absolute values. Analysis of the spectra also provides information on the absorption cross section, transition energy and bandwidth of each band, the knowledge of which is essential to check the suitability of such centres for photovoltaic applications in silicon solar cells.  相似文献   
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Cracking in PMMA containing U-shaped notches   总被引:1,自引:0,他引:1  
A procedure is proposed to evaluate the mechanical response (i.e. peak loads and load–displacement) of a notched component. A cracking criterion is given, applicable to quasi-brittle materials under monotonic loading. This procedure is based on a cohesive zone-crack model. Numerical predictions are in good agreement with a large experimental programme in which PMMA specimens of different shapes and sizes including U-notch radius and U-notch depth were tested. All experimental results are reported. The paper closes with a discussion of the proposed cracking criteria and some proposals for future work.  相似文献   
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Tensile circumferentially notched bars are examined as test specimens for measuring the yield and tensile strengths of nuclear pressure vessel steels under several conditions of irradiation and temperature that a vessel can experience during its service life, including recovery post-irradiation treatment. For all the vessel steels, notch geometries and conditions explored, it has been found that notched specimens fail by plastic collapse, and simple formulae have been derived that allow the yield and tensile strengths to be determined from the yielding and plastic collapse load of a notched specimen. Values measured in this way show good agreement with those measured by the standard tensile test method.  相似文献   
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