A selective method for the preconcentration and separation of trace amounts of Co(II) and Ni(II) ... more A selective method for the preconcentration and separation of trace amounts of Co(II) and Ni(II) by column solid phase extraction has been developed. The method is based on the adsorption of metal ions as N-(5-methyl-2-hydroxyacetophenone)-N'-(2-hydroxyacetophenone) ethylene diamine (MHE) complex on synthesized graphene oxide. Computational modeling based on PM6 semi-empirical potential energy surface was utilized to investigate the interaction of metallic complexes with graphene oxide sheet. The adsorption was achieved quantitatively on graphene oxide at pH6.0 and then the retained analyte contents on the column were quantitatively eluted with 3.0 mol L(-1) HNO3. Experimental conditions for effective separation of trace levels of the analyte ions such as pH, flow rate, concentration of eluent, sample volume and interference ions were investigated. A preconcentration factor of 250 was achieved by passing 1250 mL of sample through the solid phase, while the limit of detection of Co(II) and Ni(II) ions were found to be 0.25 and 0.18 ng mL(-1), respectively. The method was applied to the determination of analyte ions in water, black tea and tomato samples.
We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photon... more We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photonic structures to realize novel nanophotonic devices. Nanometer spatial control in the creation of single color centers in diamond is achieved by implantation of nitrogen atoms through high-aspect-ratio channels in a mica mask. Enhanced broadband single-photon emission is demonstrated by coupling nitrogen-vacancy centers to plasmonic resonators, such as metallic nanoantennas. Improved photon-collection efficiency and directed emission is demonstrated by solid immersion lenses and micropillar cavities. Thereafter, the coupling of diamond nanocrystals to the guided modes of micropillar resonators is discussed along with experimental results. Finally, we present a gas-phase-doping approach to incorporate color centers based on nickel and tungsten, in situ into diamond using microwave-plasma-enhanced chemical vapor deposition. The fabrication of silicon-vacancy centers in nanodiamonds by microwave-plasma-enhanced chemical vapor deposition is discussed in addition.
Recent efforts to define microscopic solid-immersion-lenses (SIL) by focused ion beam milling int... more Recent efforts to define microscopic solid-immersion-lenses (SIL) by focused ion beam milling into diamond substrates that are registered to a preselected single photon emitter are summarized. We show how we determine the position of a single emitter with at least 100 nm lateral and 500 nm axial accuracy, and how the milling procedure is optimized. The characteristics of a single emitter, a Nitrogen Vacancy (NV) center in diamond, are measured before and after producing the SIL and compared with each other. A count rate of 1.0 × 10(6) counts/s is achieved with a [111] oriented NV center.
NETNOMICS: Economic Research and Electronic Networking, 2014
ABSTRACT This paper intends to unravel the theoretical literature about the relationship between ... more ABSTRACT This paper intends to unravel the theoretical literature about the relationship between information technology (IT) and survival of firms through assessing and comparing the existing literature about both concepts. A selective review of relevant theoretical literature is embarked upon. In this regard, first some theories about the survival of firms such as product life cycle theory, transaction cost theory and traditional economic theory are reviewed, then the paper explores a relationship between them and information technology theories. It is observed that IT through increasing profit, learning, and expected value of firms and decreasing uncertainty, minimum efficient scale and transaction and fixed costs could affect the survival of firms.
ABSTRACT This study focuses on the impact of information technology on the survival rate of small... more ABSTRACT This study focuses on the impact of information technology on the survival rate of small and medium enterprises (SMEs) in the manufacturing sector in Malaysia. It analyses the effects of information technology on survival of SMEs in 2000 and 2005, based on two separate groups of firms. It sets out to show that information technology has positive and significant effect on survival of the firms, besides other factors such as minimum efficient size, market and firms attributes, transaction cost, uncertainty, opportunism, information asymmetry and atmosphere, profitability and learning have impact on the survival of SMEs. With using Cox proportional hazard regression model, we found that factors such as profits, R&D, location, ownership, market size, entry rate, industry growth and capital–labor ratio affect the survival of SMEs. Of equal importance is the expenditure on information technology, which is said to have an impact on the viability of firms. The results further demonstrate that being in certain stage of maturity of firms could be important in the effect of information technology on survival of SMEs.
Rare-earth-doped crystals are excellent hardware for quantum storage of photons. Additional funct... more Rare-earth-doped crystals are excellent hardware for quantum storage of photons. Additional functionality of these materials is added by their waveguiding properties allowing for on-chip photonic networks. However, detection and coherent properties of rare-earth single-spin qubits have not been demonstrated so far. Here we present experimental results on high-fidelity optical initialization, efficient coherent manipulation and optical readout of a single-electron spin of Ce(3+) ion in a yttrium aluminium garnet crystal. Under dynamic decoupling, spin coherence lifetime reaches T2 = 2 ms and is almost limited by the measured spin-lattice relaxation time T1 = 4.5 ms. Strong hyperfine coupling to aluminium nuclear spins suggests that cerium electron spins can be exploited as an interface between photons and long-lived nuclear spin memory. Combined with high brightness of Ce(3+) emission and a possibility of creating photonic circuits out of the host material, this makes cerium spins an interesting option for integrated quantum photonics.
ABSTRACT In situ surfactant-based solid-phase extraction (ISS-SPE) is proposed as a preconcentrat... more ABSTRACT In situ surfactant-based solid-phase extraction (ISS-SPE) is proposed as a preconcentration procedure for the determination of cadmium in water and food samples by flame atomic absorption spectrometry. In the present work, cetyltrimethylammonium bromide was used as a cationic surfactant, hexafluorophosphate ion as an ion-pairing agent and 4-benzylpiperidinedithiocarbamate potassium salt (K-4-BPDC) as a chelating agent. Several variables that affect the extraction efficiencies such as pH, type and amount of surfactant, concentration of ion-pairing agent, concentration of chelating agent, ionic strength and extraction time were investigated and optimized. After optimization of the complexation and extraction conditions, an enrichment factor of 40 was obtained. The calibration curve was linear in the range of 1-50 mu g L-1 and the limit of detection was 0.3 mu g L-1. The relative standard deviation for 20 mu g L-1 of cadmium was lower than 2.2%. Validation of the methodology was performed by standard addition method and analysis of certified reference materials. The method was successfully applied to the determination of cadmium in various food and water samples.
ABSTRACT A simple rapidly synergistic cloud point extraction procedure has been developed for the... more ABSTRACT A simple rapidly synergistic cloud point extraction procedure has been developed for the separation and preconcentration of trace amounts of lead from food and water samples by flame atomic absorption spectrometry (FAAS). Rapidly synergistic cloud point extraction (RS-CPE) greatly simplified and accelerated the procedure of traditional cloud point extraction (CPE). This method was accomplished in room temperature in 1 min. Non-ionic surfactant Triton X-114 was used as extractant. Octanol worked as cloud point revulsant and synergic reagent which lowered the cloud point temperature of Triton X-114 and assisted the subsequent extraction process. Some parameters that influenced cloud point extraction and subsequent determination were evaluated in detail, such as sample pH, amounts of octanol, amounts of Triton X-114, type of diluting solvent, extraction time and ionic strength, as well as interferences. Under optimized conditions (pH 8.5, octanol: 10 mu L, Triton X-114: 0.04% w/v and diluting solvent: 1 mol L-1 HNO3 in methanol), an enhancement factor of 40 could be obtained, and the detection limit (LOD) for lead was 1.6 mu g L-1. Relative standard deviation for ten replicate determinations of the standard solution containing 100 mu g L-1 lead was 2.1%. The proposed method was applied for the determination of lead in food (spinach, rice and black tea bag) and water samples and satisfactory results were obtained.
ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption s... more ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption spectrometry (FAAS) was applied to preconcentration and determination of nickel(II) ions in natural water samples. The proposed method used 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF 6 ]) as the extraction solvent and 1-(2-thiazolylazo)-2-naphthol (TAN) as the complexing agent. The extraction solvent was dissolved in the sample solution at 45°C. After dissolving, the solution was cooled in the ice bath and a cloudy solution of IL fine droplets was formed due to the decrease of IL solubility. After centrifugation, the fine droplets of extractant phase were settled at the bottom of the conical-bottom centrifuge tube. Analysis was carried out by a FAAS. Several important parameters influencing the CIAME extraction efficiency such as pH, complexing agent concentration, extraction solvent volume, salt effect, solution temperature, extraction time, centrifugation time and heating time were investigated and optimized. Under the optimum conditions, the limit of detection (LOD) was 0.8 ng/mL, and the relative standard deviation (RSD) was 3.4% for 50 ng/mL of nickel. The performance of the method was evaluated for extraction and determination of nickel in tap, mineral and seawater samples, and satisfactory results were obtained.
ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption s... more ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption spectrometry (FAAS) was applied to preconcentration and determination of nickel(II) ions in natural water samples. The proposed method used 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF 6 ]) as the extraction solvent and 1-(2-thiazolylazo)-2-naphthol (TAN) as the complexing agent. The extraction solvent was dissolved in the sample solution at 45°C. After dissolving, the solution was cooled in the ice bath and a cloudy solution of IL fine droplets was formed due to the decrease of IL solubility. After centrifugation, the fine droplets of extractant phase were settled at the bottom of the conical-bottom centrifuge tube. Analysis was carried out by a FAAS. Several important parameters influencing the CIAME extraction efficiency such as pH, complexing agent concentration, extraction solvent volume, salt effect, solution temperature, extraction time, centrifugation time and heating time were investigated and optimized. Under the optimum conditions, the limit of detection (LOD) was 0.8 ng/mL, and the relative standard deviation (RSD) was 3.4% for 50 ng/mL of nickel. The performance of the method was evaluated for extraction and determination of nickel in tap, mineral and seawater samples, and satisfactory results were obtained.
A simple, rapid, and efficient dispersive liquid-liquid microextraction method, followed by UV-Vi... more A simple, rapid, and efficient dispersive liquid-liquid microextraction method, followed by UV-Vis spectrophotometry was developed for the preconcentration and determination of Pd ions in water samples. Pd ions react with α-furildioxime (chelating agent) to form a hydrophobic complex. Various parameters were altered to study and optimize their effects on the extraction efficiency, such as pH, ligand concentration, the type and volume of extraction and dispersive solvents, extraction time, and salt concentration. Under optimized conditions, the method exhibited an enrichment factor (C org/C aq) of 25 and recovery more than 98 % within a very short extraction time. The linearity of the method ranged from 10 to 200 μg L(-1). The limit of detection was 1.1 μg L(-1). The relative standard deviation for the concentration of 100 μg L(-1) of Pd was 2.3 % (n = 10). Finally, the developed method was successfully applied to the extraction and determination of Pd in tap, river, mineral, and sea water samples.
... Preconcentration of Trace Uranium F. Shemirani et al. Farzaneh Shemirani,* Shiva Dehghan Abke... more ... Preconcentration of Trace Uranium F. Shemirani et al. Farzaneh Shemirani,* Shiva Dehghan Abkenar, and Mohammad Reza Jamali ... Acta, 314, 51 (1995). 31 B. Narasimha Murty, YVS Jagannath, RB Yadav, CK Ramamurty, and S. Syamsundar, Talanta, 44, 283 (1997). 32 Dj. ...
A selective method for the preconcentration and separation of trace amounts of Co(II) and Ni(II) ... more A selective method for the preconcentration and separation of trace amounts of Co(II) and Ni(II) by column solid phase extraction has been developed. The method is based on the adsorption of metal ions as N-(5-methyl-2-hydroxyacetophenone)-N'-(2-hydroxyacetophenone) ethylene diamine (MHE) complex on synthesized graphene oxide. Computational modeling based on PM6 semi-empirical potential energy surface was utilized to investigate the interaction of metallic complexes with graphene oxide sheet. The adsorption was achieved quantitatively on graphene oxide at pH6.0 and then the retained analyte contents on the column were quantitatively eluted with 3.0 mol L(-1) HNO3. Experimental conditions for effective separation of trace levels of the analyte ions such as pH, flow rate, concentration of eluent, sample volume and interference ions were investigated. A preconcentration factor of 250 was achieved by passing 1250 mL of sample through the solid phase, while the limit of detection of Co(II) and Ni(II) ions were found to be 0.25 and 0.18 ng mL(-1), respectively. The method was applied to the determination of analyte ions in water, black tea and tomato samples.
We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photon... more We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photonic structures to realize novel nanophotonic devices. Nanometer spatial control in the creation of single color centers in diamond is achieved by implantation of nitrogen atoms through high-aspect-ratio channels in a mica mask. Enhanced broadband single-photon emission is demonstrated by coupling nitrogen-vacancy centers to plasmonic resonators, such as metallic nanoantennas. Improved photon-collection efficiency and directed emission is demonstrated by solid immersion lenses and micropillar cavities. Thereafter, the coupling of diamond nanocrystals to the guided modes of micropillar resonators is discussed along with experimental results. Finally, we present a gas-phase-doping approach to incorporate color centers based on nickel and tungsten, in situ into diamond using microwave-plasma-enhanced chemical vapor deposition. The fabrication of silicon-vacancy centers in nanodiamonds by microwave-plasma-enhanced chemical vapor deposition is discussed in addition.
Recent efforts to define microscopic solid-immersion-lenses (SIL) by focused ion beam milling int... more Recent efforts to define microscopic solid-immersion-lenses (SIL) by focused ion beam milling into diamond substrates that are registered to a preselected single photon emitter are summarized. We show how we determine the position of a single emitter with at least 100 nm lateral and 500 nm axial accuracy, and how the milling procedure is optimized. The characteristics of a single emitter, a Nitrogen Vacancy (NV) center in diamond, are measured before and after producing the SIL and compared with each other. A count rate of 1.0 × 10(6) counts/s is achieved with a [111] oriented NV center.
NETNOMICS: Economic Research and Electronic Networking, 2014
ABSTRACT This paper intends to unravel the theoretical literature about the relationship between ... more ABSTRACT This paper intends to unravel the theoretical literature about the relationship between information technology (IT) and survival of firms through assessing and comparing the existing literature about both concepts. A selective review of relevant theoretical literature is embarked upon. In this regard, first some theories about the survival of firms such as product life cycle theory, transaction cost theory and traditional economic theory are reviewed, then the paper explores a relationship between them and information technology theories. It is observed that IT through increasing profit, learning, and expected value of firms and decreasing uncertainty, minimum efficient scale and transaction and fixed costs could affect the survival of firms.
ABSTRACT This study focuses on the impact of information technology on the survival rate of small... more ABSTRACT This study focuses on the impact of information technology on the survival rate of small and medium enterprises (SMEs) in the manufacturing sector in Malaysia. It analyses the effects of information technology on survival of SMEs in 2000 and 2005, based on two separate groups of firms. It sets out to show that information technology has positive and significant effect on survival of the firms, besides other factors such as minimum efficient size, market and firms attributes, transaction cost, uncertainty, opportunism, information asymmetry and atmosphere, profitability and learning have impact on the survival of SMEs. With using Cox proportional hazard regression model, we found that factors such as profits, R&D, location, ownership, market size, entry rate, industry growth and capital–labor ratio affect the survival of SMEs. Of equal importance is the expenditure on information technology, which is said to have an impact on the viability of firms. The results further demonstrate that being in certain stage of maturity of firms could be important in the effect of information technology on survival of SMEs.
Rare-earth-doped crystals are excellent hardware for quantum storage of photons. Additional funct... more Rare-earth-doped crystals are excellent hardware for quantum storage of photons. Additional functionality of these materials is added by their waveguiding properties allowing for on-chip photonic networks. However, detection and coherent properties of rare-earth single-spin qubits have not been demonstrated so far. Here we present experimental results on high-fidelity optical initialization, efficient coherent manipulation and optical readout of a single-electron spin of Ce(3+) ion in a yttrium aluminium garnet crystal. Under dynamic decoupling, spin coherence lifetime reaches T2 = 2 ms and is almost limited by the measured spin-lattice relaxation time T1 = 4.5 ms. Strong hyperfine coupling to aluminium nuclear spins suggests that cerium electron spins can be exploited as an interface between photons and long-lived nuclear spin memory. Combined with high brightness of Ce(3+) emission and a possibility of creating photonic circuits out of the host material, this makes cerium spins an interesting option for integrated quantum photonics.
ABSTRACT In situ surfactant-based solid-phase extraction (ISS-SPE) is proposed as a preconcentrat... more ABSTRACT In situ surfactant-based solid-phase extraction (ISS-SPE) is proposed as a preconcentration procedure for the determination of cadmium in water and food samples by flame atomic absorption spectrometry. In the present work, cetyltrimethylammonium bromide was used as a cationic surfactant, hexafluorophosphate ion as an ion-pairing agent and 4-benzylpiperidinedithiocarbamate potassium salt (K-4-BPDC) as a chelating agent. Several variables that affect the extraction efficiencies such as pH, type and amount of surfactant, concentration of ion-pairing agent, concentration of chelating agent, ionic strength and extraction time were investigated and optimized. After optimization of the complexation and extraction conditions, an enrichment factor of 40 was obtained. The calibration curve was linear in the range of 1-50 mu g L-1 and the limit of detection was 0.3 mu g L-1. The relative standard deviation for 20 mu g L-1 of cadmium was lower than 2.2%. Validation of the methodology was performed by standard addition method and analysis of certified reference materials. The method was successfully applied to the determination of cadmium in various food and water samples.
ABSTRACT A simple rapidly synergistic cloud point extraction procedure has been developed for the... more ABSTRACT A simple rapidly synergistic cloud point extraction procedure has been developed for the separation and preconcentration of trace amounts of lead from food and water samples by flame atomic absorption spectrometry (FAAS). Rapidly synergistic cloud point extraction (RS-CPE) greatly simplified and accelerated the procedure of traditional cloud point extraction (CPE). This method was accomplished in room temperature in 1 min. Non-ionic surfactant Triton X-114 was used as extractant. Octanol worked as cloud point revulsant and synergic reagent which lowered the cloud point temperature of Triton X-114 and assisted the subsequent extraction process. Some parameters that influenced cloud point extraction and subsequent determination were evaluated in detail, such as sample pH, amounts of octanol, amounts of Triton X-114, type of diluting solvent, extraction time and ionic strength, as well as interferences. Under optimized conditions (pH 8.5, octanol: 10 mu L, Triton X-114: 0.04% w/v and diluting solvent: 1 mol L-1 HNO3 in methanol), an enhancement factor of 40 could be obtained, and the detection limit (LOD) for lead was 1.6 mu g L-1. Relative standard deviation for ten replicate determinations of the standard solution containing 100 mu g L-1 lead was 2.1%. The proposed method was applied for the determination of lead in food (spinach, rice and black tea bag) and water samples and satisfactory results were obtained.
ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption s... more ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption spectrometry (FAAS) was applied to preconcentration and determination of nickel(II) ions in natural water samples. The proposed method used 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF 6 ]) as the extraction solvent and 1-(2-thiazolylazo)-2-naphthol (TAN) as the complexing agent. The extraction solvent was dissolved in the sample solution at 45°C. After dissolving, the solution was cooled in the ice bath and a cloudy solution of IL fine droplets was formed due to the decrease of IL solubility. After centrifugation, the fine droplets of extractant phase were settled at the bottom of the conical-bottom centrifuge tube. Analysis was carried out by a FAAS. Several important parameters influencing the CIAME extraction efficiency such as pH, complexing agent concentration, extraction solvent volume, salt effect, solution temperature, extraction time, centrifugation time and heating time were investigated and optimized. Under the optimum conditions, the limit of detection (LOD) was 0.8 ng/mL, and the relative standard deviation (RSD) was 3.4% for 50 ng/mL of nickel. The performance of the method was evaluated for extraction and determination of nickel in tap, mineral and seawater samples, and satisfactory results were obtained.
ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption s... more ABSTRACT Cold-induced aggregation microextraction (CIAME) combined with flame atomic absorption spectrometry (FAAS) was applied to preconcentration and determination of nickel(II) ions in natural water samples. The proposed method used 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF 6 ]) as the extraction solvent and 1-(2-thiazolylazo)-2-naphthol (TAN) as the complexing agent. The extraction solvent was dissolved in the sample solution at 45°C. After dissolving, the solution was cooled in the ice bath and a cloudy solution of IL fine droplets was formed due to the decrease of IL solubility. After centrifugation, the fine droplets of extractant phase were settled at the bottom of the conical-bottom centrifuge tube. Analysis was carried out by a FAAS. Several important parameters influencing the CIAME extraction efficiency such as pH, complexing agent concentration, extraction solvent volume, salt effect, solution temperature, extraction time, centrifugation time and heating time were investigated and optimized. Under the optimum conditions, the limit of detection (LOD) was 0.8 ng/mL, and the relative standard deviation (RSD) was 3.4% for 50 ng/mL of nickel. The performance of the method was evaluated for extraction and determination of nickel in tap, mineral and seawater samples, and satisfactory results were obtained.
A simple, rapid, and efficient dispersive liquid-liquid microextraction method, followed by UV-Vi... more A simple, rapid, and efficient dispersive liquid-liquid microextraction method, followed by UV-Vis spectrophotometry was developed for the preconcentration and determination of Pd ions in water samples. Pd ions react with α-furildioxime (chelating agent) to form a hydrophobic complex. Various parameters were altered to study and optimize their effects on the extraction efficiency, such as pH, ligand concentration, the type and volume of extraction and dispersive solvents, extraction time, and salt concentration. Under optimized conditions, the method exhibited an enrichment factor (C org/C aq) of 25 and recovery more than 98 % within a very short extraction time. The linearity of the method ranged from 10 to 200 μg L(-1). The limit of detection was 1.1 μg L(-1). The relative standard deviation for the concentration of 100 μg L(-1) of Pd was 2.3 % (n = 10). Finally, the developed method was successfully applied to the extraction and determination of Pd in tap, river, mineral, and sea water samples.
... Preconcentration of Trace Uranium F. Shemirani et al. Farzaneh Shemirani,* Shiva Dehghan Abke... more ... Preconcentration of Trace Uranium F. Shemirani et al. Farzaneh Shemirani,* Shiva Dehghan Abkenar, and Mohammad Reza Jamali ... Acta, 314, 51 (1995). 31 B. Narasimha Murty, YVS Jagannath, RB Yadav, CK Ramamurty, and S. Syamsundar, Talanta, 44, 283 (1997). 32 Dj. ...
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