排序方式: 共有28条查询结果,搜索用时 62 毫秒
1.
Using an improved synthesis of pyochelin, a siderophore common to several pathogenic Pseudomonas species, three functionalized pyochelin analogs were efficiently synthesized starting from appropriate 2-hydroxybenzonitriles. 相似文献
2.
The efficient market hypothesis (EMH) states that asset prices fully reflect all available information. As a result, speculators cannot predict the future behavior of asset prices and earn excess profits at least after adjusting for risk. Although initial tests of the EMH were performed on stock market data, the EMH was soon applied to other markets including foreign exchange (FX). This study uses the detrended fluctuation analysis (DFA) technique to test 01:12:2005–18:04:2010 Iranian Rial/US Dollar exchange rate time series data to see if it can be explained by the weak form of the EMH. Moreover, to determine changes in the degree of inefficiency over time, the whole period has been divided into four subperiods. The study shows that the Iranian Forex market (the Rial/Dollar case) is weak-form inefficient over the whole period and in each of the subperiods. However, the degree of inefficiency is not constant over time. The findings suggest that profitable risk-adjusted trades could be made using past data. 相似文献
3.
The room temperature reaction between gas phase water and active carbon to form carbon dioxide and hydrogen on a platinized titanium dioxide catalyst, illuminated with band gap radiation, is reported. Using the same catalyst system, ethylene is converted to ethane, carbon dioxide, hydrogen and a small amount of methane. 相似文献
4.
Khaled Osati Ali Salajegheh Mohammad Mahdavi Kamran Chapi Arash Malekian 《Isotopes in environmental and health studies》2014,50(2):169-183
Karst springs of the Zagros Mountains contribute a significant amount to agricultural and human water demands of western and south-western Iran. For an adequate management of available water resources in semi-arid and arid regions, sufficient hydrological monitoring is needed, and hydro-chemical and isotope hydrological data provide important additional information. About 350 water samples were collected from precipitation, river water, and karst springs of the upper part of the Karkheh River Basin (20,895 km2) located between 33°35′ and 34°55′ North and 46°22′ and 49°10′ East with elevations ranging from 928 to 3563 m above sea level. Sampling was conducted in monthly time resolution from August 2011 to July 2012. All samples were analysed for hydro-chemical parameters (pH, electrical conductivity, and major ions) and stable isotopes (deuterium, oxygen-18). Isotope values of precipitation indicate a local meteoric water line (Zagros MWL δ2H=6.8 δ18O+10.1; R2=0.99) situated between the Mediterranean MWL and Global MWL. Spring and river water isotope values vary between?7.1 and?4.1 ‰, and?38 and?25 ‰ for δ18O and δ2H, respectively, responding to winter snowmelt and evaporation. This work implements stable isotopes and hydro-chemical information of springs and river water to understand hydrological and hydro-geological interrelations in karstic semi-arid areas and helps to improve the current water resources management practices of western Iran. 相似文献
5.
Hossein Tavallali Hossein Malekzadeh Mohammad Ali Karimi Mahmood Payehghadr Gohar Deilamy-Rad Mahboobeh Tabandeh 《Arabian Journal of Chemistry》2019,12(7):1487-1495
Multi-walled carbon nanotubes (MWCNTs) were chemically functionalized by glutaric dihydrazide (GDH) and characterized with FT-IR technique. This new sorbent was used for enrichment and preconcentration of Co(II), Cd(II), Pb(II), and Pd(II) ions. The adsorption was achieved quantitatively on MWCNTs at pH 4.0, and then the retained metal ions on the adsorbent were eluted with 1.5 mol L?1 HNO3. The effects of analytical parameters including pH of the solution, eluent type, sample volume, and matrix ions were investigated for optimization of the presented procedure. The adsorption capacity of the adsorbent at optimum conditions was found to be 33.6, 29.2, 22.1, and 36.0 mg g?1 for Co(II), Cd(II), Pb(II), and Pd(II), respectively. The LOD values of the method were 0.16, 0.19, 0.17, and 0.12 ng mL?1 (3Sb, n = 10) for Co(II), Cd(II), Pb(II), and Pd(II), respectively. The RSDs values of the method were 0.75, 0.85, 1.16, and 1.30 ng mL?1 for Co(II), Cd(II), Pb(II), and Pd(II), respectively. The method was applied for the determination of analytes in soil, well water, and wastewater samples with satisfactory results. 相似文献
6.
Pierre Braunstein Chantal Charles Richard D. Adams Ralph Layland 《Journal of Cluster Science》1996,7(2):145-154
The reaction of the siloxyl containing ferrate [Fe(CO)3(
1-dppm){Si(OMe)3}]–,1 (dppm = Ph2PCH2PPh2) with Sn(OAc)2(n-Bu)2 has yielded the new dimeric complex [Fe(CO)3(
1-dppm){µ-Sn(n-Bu)2}]2, 3 in 89% yield. Compound3 was characterized crystallographically and was found to be a centrosym-etrical molecule with a rhomboidal Fe2Sn2 cluster at the center. Each iron atom contains me
1-dppm ligand. Compound3 was found to react with [Pd(dmba) (µ-Cl)]2 (dmba=dimethylbenzylamine) to yield the new complexmer-[Fe(CO)3{Sn(n-Bu)2}(µ-dppm)Pd(dmba)Cl]2, 4 by attachment of a palla-dium grouping to each of the uncoordinated phosphorus atoms in 3. Crystal data for 3: space groupP
,a=11.399(2) Å, 6=15.98(3) Å, c=10.869(3) Å, =94.10(2)°.=100.56(2)°, =69.35(1)°,Z=2, 3533 reflections,R=0.034. 相似文献
7.
J. Hadian A. Sonboli S. Nejad Ebrahimi M. H. Mirjalili 《Chemistry of Natural Compounds》2006,42(2):175-177
The essential oil of Nepeta satureioides Boiss. from Iran was isolated by hydrodistillation in yield of 0.06% (w/w). The chemical composition of the essential oil
was analyzed by GC and GC-MS. Forty-five compounds accounting for 97.4% of the total oil were identified. The major components
were linalool (23.8%), (Z,E)-farnesol (14.7%), linalyl acetate (11.1%), β-caryophyllene (6.6%), lavandulol acetate (6.6%), caryophyllene oxide (6.4%), and (Z)-β-farnesene (3.4%). Oxygenated terpenoids were the main group of compounds.
Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 144–145, March–April, 2006. 相似文献
8.
9.
10.
The hydrodistilled essential oil composition from the aerial parts of Salvia macilenta (Lamiaceae) from Iran was analyzed by GC and GC-MS. The oil analysis confirmed the characterization of thirty-one compounds, accounting for 99.4% of the total oil. Analysis of the oil showed that the oil of S. macilenta was rich in monoterpene hydrocarbons with a-pinene (60%) as the main component followed by γ-elemene (6.1%), thymol (5.2%), elemol (4.7%), and β-caryophyllene (4.1%).__________Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 136–137, March–April, 2005. 相似文献