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91.
The aim of this study is to examine seasonal changes in Cu and Co concentrations of three plant species for monitoring the effects of pollution in Elazig,Turkey.For this purpose,the leaves of the Pinus nigra L.,Cedrus libani and Cupressus arizonica together with soil samples were collected from different points depending on traffic intensity,nearness the city center and cement factory as well as control location during different months of the year.Flame atomic absorption spectrophotometer(FAAS) was used for measurement of the metals in clear digests after the dry ashing method.Copper and Co concentrations were in the ranges from 1.3to 2.6mg.kg-1 and相似文献   
92.
Let K be an imaginary quadratic field with class number one and ? be a rational prime that splits in K. We prove that mod ?, a system of Hecke eigenvalues occurring in the first cohomology group of some congruence subgroup Γ of SL2(OK) can be realized, up to twist, in the first cohomology with trivial coefficients after increasing the level of Γ by (?).  相似文献   
93.
Strategic delay and restricted offers are two modes of signaling bargaining power in alternating offers bargaining games. This paper shows that when both modes are available, the best signaling strategy of the “strong” type of the informed player consists of a pure strategic delay followed by an offer on the whole pie. There is no signaling motivation for issue-by-issue bargaining when the issues are perfectly substitutable. Received: July 1996/Final version: August 1999  相似文献   
94.
The attribution of nitrous oxide (N2O) emission to organic and inorganic N fertilizers requires understanding of how these inputs affect the two biological processes, i.e. denitrification and nitrification. Contradictory findings have been reported when the effects of organic and inorganic fertilizers on nitrous oxide emission were compared. Here we aimed to contribute to the understanding of such variation using 15N‐labelling techniques. We determined the processes producing N2O, and tested the effects of soil moisture, N rates, and the availability of organic matter. In a pot experiment, we compared soil treated with biogas waste (BGW) and mineral ammonium sulphate (Min‐N) applied at four rates under two soil moisture regimes. We also tested biogas waste, conventional cattle slurry and mineral N fertilizer in a grassland field experiment. During the first 37 days after application we observed N2O emissions of 5.6 kg N2O‐N ha?1 from soils supplied with biogas waste at a rate of 360 kg N ha?1. Fluxes were ca. 5‐fold higher at 85% than at 65% water holding capacity (WHC). The effects of fertilizer types and N rates on N2O emission were significant only when the soil moisture was high. Organic fertilizer treated soils showed much higher N2O emissions than those receiving mineral fertilizer in both, pot and field experiment. Over all the treatments the percentage of the applied N emitted as N2O was 2.56% in BGW but only 0.68% in Min‐N. In the pot experiment isotope labelling indicated that 65–95% of the N2O was derived from denitrification for all fertilizer types. However, the ratio of denitrification/nitrification derived N2O was lower at 65% than at 85% WHC. We speculate that the application of organic matter in conjunction with ammonium nitrogen first leads to a decrease in denitrification‐derived N2O emission compared with soil receiving mineral fertilizer. However, at later stages when denitrification becomes C‐limited, higher N2O emissions are induced when the soil moisture is high. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
95.
Oxalacetic acid and pyruvic acid derivatives have been synthesized efficiently in high yields by the treatment of 4-ethoxycarbonyl-5-phenyl-2,3-furandione and 4-benzoyl-5-phenyl-2,3-furandione with 2-phenylindole at room temperature and converted to simple derivatives such as an ester or a hydrazone.  相似文献   
96.
We consider supplier diversification in an EOQ type inventory setting with multiple suppliers and binomial yields. We characterize the optimal policy for the model and show that, in this case, it does not pay to diversify, in contrast to previous results in the random yield literature.  相似文献   
97.
This paper describes a two-level simulated annealing heuristic for the joint problem of object placement and request routing in a Content Distribution Network (CDN) with constraints pertaining to server capacity and end-to-end object transfer delay. A CDN is a technology that is used to efficiently distribute electronic content throughout an existing network. The two-level solution procedure is composed of an outer and an inner simulated annealing algorithms. Computational experiments are conducted by comparing the proposed procedure with several truncated exact solution algorithms on randomly generated Internet topologies.  相似文献   
98.
In this paper we studied the general properties of Bertrand curves and their characterizations in Riemann–Otsuki space.  相似文献   
99.
The authors report on a robust method for the synthesis of gold nanorods (AuNRs) with tunable dimensions and longitudinal surface plasmon resonance. The method relies on seed-mediated particle growth in the presence of benzalkonium chloride (BAC) in place of the widely used surfactant cetyltrimethyl ammonium bromide (CTAB). Uniform AuNRs were obtained by particle growth in solution, and BAC is found to stabilize the AuNRs for >1 year. The SERS activity of the resulting AuNRs is essentially identical to that of CTAB-protected nanorods. The SERS activity of the BAC protected nanorods was applied to the quantitative analysis of potato virus X (PVX). The calibration plot for PVX is linear in the 10 to 750 ng?mL?1 concentration range, and the detection limit is 2.2 ng?mL?1.
Graphical abstract SERS-active gold nanorods (AuNRs) have been prepared by using benzalkonium chloride as stabilization agent. Effects of chemical parameters on AuNRs have been explored and AuNRs were used in quantitative analysis of potato virus X (PVX).
  相似文献   
100.
This study focuses on the preparation, single crystal X-ray diffraction, characterization, and optical properties of some anthraquinone-based dyes. The anthraquinone-based antimicrobial dye N-{2-[(9,10-dioxo-9,10-dihydroanthracen-1-yl)amino]-2-oxoethyl}-N,N-dimethylbutan-1-aminium chloride monohydrate (III) was obtained from 1-aminoanthraquinone (I) via 2-chloro-N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)acetamide (II) using known preparation and characterization methods. Single crystal X-ray diffraction analysis of III revealed a monoclinic system, space group P21/n, Z = 4. Photoluminescence properties of anthraquinone dyes I–III were also investigated. These dyes gave an intense emission (λmax = 341 nm) upon the irradiation by UV light and showed photoluminescence quantum yields of 73 %, 66 %, and 61 % with long excited-state lifetimes of 6.87 ns, 6.14 ns, and 5.69 ns, respectively. These anthraquinone dyes are of interest as an organic light emitting material for electroluminescent devices.  相似文献   
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