Thermally oxidized aluminum as catalyst-support layer for vertically aligned single-walled carbon nanotube growth using ethanol

Characteristics and role of Al oxide (Al-O) films used as catalyst-support layer for vertical growth of single-walled carbon nanotubes (SWCNTs) were studied. EB-deposited Al films (20 nm) were thermally oxidized at 400 °C (10 min, static air) to produce the most appropriate surface structure of Al-O. Al-O catalyst-support layers were characterized using various analytical measurements, i.e., atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and spectroscopy ellipsometry (SE). The thermally oxidized Al-O has a highly roughened surface, and also has the most suitable surface chemical states compared to other type of Al-O support layers. We suggest that the surface of thermally oxidized Al-O characterized in this work enhanced Co catalyst activity to promote the vertically aligned SWCNT growth.     

The stability of a shearing viscous star with an electromagnetic field

We analyze the role of the electromagnetic field for the stability of a shearing viscous star with spherical symmetry. Matching conditions are given for the interior and the exterior metrics. We use a perturbation scheme to construct the collapse equation. The range of instability is explored in Newtonian and post Newtonian (pN) limits. We conclude that the electromagnetic field diminishes the effects of the shearing viscosity in the instability range and makes the system more unstable in both Newtonian and post Newtonian approximations.     

The emission spectrum of SeO in the far ultraviolet

The emission spectrum of SeO in the far ultraviolet first observed by Haranath (1) at low dispersion has been photographed in the region 2480-1930 Å under medium resolution and a reanalysis of the vibrational structure of the bands has been presented. Beginning at the longer wavelength end, the spectrum has been analyzed into five band systems which are designated as $\text{c(}{}^1\text{Σ}{}^{\mathrm{+}}\text{)-b(}{}^1\text{Σ}{}^{\mathrm{+}}\text{)}$, x₂-x₁, y₂-y₁, $\text{C(}{}^3\text{Π}\text{)-X}{}^3\text{Σ}{}^{\mathrm{?}}$, and $\text{D(}{}^3\text{Σ}{}^{\mathrm{?}}\text{)-X}{}^3\text{Σ}{}^{\mathrm{?}}$. The lower state of the c-b system is found to be the upper state of the $\text{b(}{}^1\text{Σ}{}^{\mathrm{+}}\text{)-X}{}^3\text{Σ}{}^{\mathrm{?}}$ system observed recently by us (2). The derived constants in cm^?1 for SeO are as follows (the constants of the b state are those derived from Ref. 2).

     

104.

Common fixed points of two maps in cone metric spaces     

Akbar Azam  Muhammad Arshad  Ismat Beg 《Rendiconti del Circolo Matematico di Palermo》2008,57(3):433-441

We prove the existence of points of coincidence and common fixed points of a pair of self-mappings satisfying a generalized contractive condition in cone metric spaces. Our results generalize several well-known recent and classical results.      

105.

Self‐Assembled Heteroleptic Zn(II) Dithiocarbamate‐Based 2D‐Interwoven Supramolecular Giant Macrocycles and Their Redox Properties     

Zafar Ali Khan Khattak  Zia‐ur ‐Rehman  Azam Khan  Afzal Shah  Waqar Zaid  Amin Badshah  Mohammed Fettouhi  Atif Fazal 《Heteroatom Chemistry》2014,25(4):238-244

This article presents a new heteroleptic Zn(II) dithiocarbamate ( 1 ) having molecules linked together via H···H and π···π interactions to form a giant hexanuclear macrocycle. These macrocycles are connected together through S···H interactions to offer a unique two‐dimensional cloth‐like interwoven architecture in the solid state. The redox behavior of the complex deposited on the surface of a glassy carbon electrode was investigated in different pH media. The analyte was found to oxidize and reduce in a pH‐dependent irreversible manner. On the basis of the electrochemical findings, redox mechanistic pathways were proposed.     

106.

Novel Surfactant for the Reduction of CO2/Brine Interfacial Tension     

Muhammad Sagir  Isa M. Tan  Muhammad Mushtaq  Lukman Ismail  Muhammad Nadeem  Muhammad Rizwan Azam 《Journal of Dispersion Science and Technology》2014,35(3):463-470

The synthesis of novel CO₂ philic surfactant using maleic anhydride and dipropylene tertiary butyl alcohol is reported. The synthesis involved the esterification of maleic anhydride to produce bis(2-(2-(tert-butoxy)propoxy)propyl) maleate and subsequent sulfonation of the esterified product. Para toluene sulfonic acid was employed as catalyst for the esterification reaction. The esterification reaction was optimized for the maximum yield of 98% of bis(2-(2-(tert-butoxy)propoxy)propyl) maleate. The esterification reaction kinetics employing heterogeneous catalyst were also studied. Although this is a bimolecular reaction, a first order reaction kinetics with respect to acid has been observed. The activation energy was found to be 58.71 kJ/mol. The diester was followed by the sulfonation process and a yield of 85% of surfactant was achieved. The synthesized surfactant successfully lowered down the IFT between CO_2/brine to 1.93 mN/m. This surfactant has a great potential to be used for CO₂-EOR applications.     

107.

An explorative study on diarylquinoline-based inhibitor targeting Enterococcus faecium MurF     

Azam  Mohammed Afzal  Manoj  Vyshaag Chembakam veetil 《Structural chemistry》2021,32(1):115-125

Structural Chemistry - Enterococcus faecium MurF (EfMurF) enzyme catalyzes the addition of d-alanyl-d-alanine to form murein UDP-N-acetylmuramoyl-pentapeptide. This is the last cytoplasmic step of...     

108.

Enhancing water splitting via weakening H2 and O2 adsorption on NiCo-LDH@CdS due to interstitial nitrogen doping: A close look at the mechanism of electron transfer     

Azam Pirkarami  Sousan Rasouli  Ebrahim Ghasemi 《Journal of Energy Chemistry》2021,(6):118-130

This paper is a report on the development of a convenient approach to fabricating a very efficient hybrid photoelectrocatalyst for water splitting.This photoele...     

109.

Effect of mass transfer limitations on catalyst performance during reduction and carburization of iron based Fischer-Tropsch synthesis catalysts     

Akbar Zamaniyan  Yadollah Mortazavi  Abbas Ali Khodadadi  Ali Nakhaei Pour 《天然气化学杂志》2013,(5):795-803

Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based catalysts.In this study,Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation method.To investigate the intraparticle mass transfer limitation under reduction,activation and reaction steps,and its effect on catalytic performance,catalyst pellets with different sizes of 6,3,1 and 0.5 mm have been prepared.All catalysts were calcined,pretreated and tested under similar conditions.The catalysts were activated in hydrogen (5%H2in N2) at 450℃ for 3 h and exposed to syngas (H2/CO=1) at 270℃ and atmospheric pressure for 40 h.Afterwards,FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290℃,17 bar and a feed flow (syngas H2/CO=1) rate of 3 L/h (STP).Using small pellets resulted in higher CO conversion,FT reaction rate and C5+ productivity as compared with larger pellets.The small pellets reached steady state conditions just 20 h after starting the reaction.Whereas for larger pellets,CO conversion,FT reaction rate and C5+ productivity increased gradually,and reached steady state and maximum values after 120 h of operation.The results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst activation.Also the results indicate that some effects of mass transfer limitations in activation step,can be compensated in the reaction step.The results can be used for better design of iron based catalyst to improve the process economy.     

110.

Comparative vapour phase FTIR spectra and vibrational assignment of manganese pentacarbonyls derivatives of the type XMn(CO)5: (where X=Br, Cl, I, H, D, CH3, CD3, CF3)     

Mahmood Z  Azam M  Mushtaq A  Kausar R  Kausar S  Gilani SR 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(2):445-452

The infrared spectra of pure Mn(CO)(5)X in the region 4000-400 cm(-1) has been obtained in the vapour phase. The observed spectrum has been analyzed to distinguish the fundamental frequencies, the rotational-vibrational and structure, and overtone and combination frequencies. The assignment of the observed vapour phase frequencies to the fundamental modes of vibration has been made on C(4V) symmetry. The weak peaks due to XMn(CO)(4)((13)CO) molecules have been measured and assigned for all molecules. This study provides a comprehensive comparison of these compounds, with all of these data the assignment of frequencies is reviewed and a set of quite unambiguous assignments made. The significant finding in this regards are that, it is not necessary to assume lower than C(4V) symmetry for XMn(CO)(5) as has been done in previous consideration of some infrared spectrum of these compounds.     

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State	$\text{T}{}_{\mathrm{e}}$	$\text{ω}{}_{\mathrm{e}}$	$\text{ω}{}_{\mathrm{e}}\text{x}{}_{\mathrm{e}}$	λ
$\text{y}{}_2$	$\text{y}{}_1\text{+ 47830}$	974	6.0
$\text{y}{}_1$	$\text{y}{}_1$	906	21.0
$\text{x}{}_2$	$\text{x}{}_1\text{+ 46009}$	993	2.0
$\text{x}{}_1$	$\text{x}{}_1$	877	8.0
$\text{c(}{}^1\text{Σ}{}^{\mathrm{+}}\text{)}$	53080	954	13.0
$\text{D(}{}^3\text{Σ}{}^{\mathrm{?}}\text{)}\text{F}{}_2$	51422	955	9.3
F1	51356	955	8.5	～36
$\text{C(}{}^3\text{Π}\text{)}$	50873	1034	9.3
$\text{b(}{}^1\text{Σ}{}^{\mathrm{+}}\text{)}$	9570.7	834.9	5.5

Common fixed points of two maps in cone metric spaces

We prove the existence of points of coincidence and common fixed points of a pair of self-mappings satisfying a generalized contractive condition in cone metric spaces. Our results generalize several well-known recent and classical results.      

Self‐Assembled Heteroleptic Zn(II) Dithiocarbamate‐Based 2D‐Interwoven Supramolecular Giant Macrocycles and Their Redox Properties

This article presents a new heteroleptic Zn(II) dithiocarbamate ( 1 ) having molecules linked together via H···H and π···π interactions to form a giant hexanuclear macrocycle. These macrocycles are connected together through S···H interactions to offer a unique two‐dimensional cloth‐like interwoven architecture in the solid state. The redox behavior of the complex deposited on the surface of a glassy carbon electrode was investigated in different pH media. The analyte was found to oxidize and reduce in a pH‐dependent irreversible manner. On the basis of the electrochemical findings, redox mechanistic pathways were proposed.     

Novel Surfactant for the Reduction of CO2/Brine Interfacial Tension

The synthesis of novel CO₂ philic surfactant using maleic anhydride and dipropylene tertiary butyl alcohol is reported. The synthesis involved the esterification of maleic anhydride to produce bis(2-(2-(tert-butoxy)propoxy)propyl) maleate and subsequent sulfonation of the esterified product. Para toluene sulfonic acid was employed as catalyst for the esterification reaction. The esterification reaction was optimized for the maximum yield of 98% of bis(2-(2-(tert-butoxy)propoxy)propyl) maleate. The esterification reaction kinetics employing heterogeneous catalyst were also studied. Although this is a bimolecular reaction, a first order reaction kinetics with respect to acid has been observed. The activation energy was found to be 58.71 kJ/mol. The diester was followed by the sulfonation process and a yield of 85% of surfactant was achieved. The synthesized surfactant successfully lowered down the IFT between CO_2/brine to 1.93 mN/m. This surfactant has a great potential to be used for CO₂-EOR applications.     

An explorative study on diarylquinoline-based inhibitor targeting Enterococcus faecium MurF

Structural Chemistry - Enterococcus faecium MurF (EfMurF) enzyme catalyzes the addition of d-alanyl-d-alanine to form murein UDP-N-acetylmuramoyl-pentapeptide. This is the last cytoplasmic step of...     

Enhancing water splitting via weakening H2 and O2 adsorption on NiCo-LDH@CdS due to interstitial nitrogen doping: A close look at the mechanism of electron transfer

This paper is a report on the development of a convenient approach to fabricating a very efficient hybrid photoelectrocatalyst for water splitting.This photoele...     

Effect of mass transfer limitations on catalyst performance during reduction and carburization of iron based Fischer-Tropsch synthesis catalysts

Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based catalysts.In this study,Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation method.To investigate the intraparticle mass transfer limitation under reduction,activation and reaction steps,and its effect on catalytic performance,catalyst pellets with different sizes of 6,3,1 and 0.5 mm have been prepared.All catalysts were calcined,pretreated and tested under similar conditions.The catalysts were activated in hydrogen (5%H2in N2) at 450℃ for 3 h and exposed to syngas (H2/CO=1) at 270℃ and atmospheric pressure for 40 h.Afterwards,FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290℃,17 bar and a feed flow (syngas H2/CO=1) rate of 3 L/h (STP).Using small pellets resulted in higher CO conversion,FT reaction rate and C5+ productivity as compared with larger pellets.The small pellets reached steady state conditions just 20 h after starting the reaction.Whereas for larger pellets,CO conversion,FT reaction rate and C5+ productivity increased gradually,and reached steady state and maximum values after 120 h of operation.The results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst activation.Also the results indicate that some effects of mass transfer limitations in activation step,can be compensated in the reaction step.The results can be used for better design of iron based catalyst to improve the process economy.     

Comparative vapour phase FTIR spectra and vibrational assignment of manganese pentacarbonyls derivatives of the type XMn(CO)5: (where X=Br, Cl, I, H, D, CH3, CD3, CF3)

The infrared spectra of pure Mn(CO)(5)X in the region 4000-400 cm(-1) has been obtained in the vapour phase. The observed spectrum has been analyzed to distinguish the fundamental frequencies, the rotational-vibrational and structure, and overtone and combination frequencies. The assignment of the observed vapour phase frequencies to the fundamental modes of vibration has been made on C(4V) symmetry. The weak peaks due to XMn(CO)(4)((13)CO) molecules have been measured and assigned for all molecules. This study provides a comprehensive comparison of these compounds, with all of these data the assignment of frequencies is reviewed and a set of quite unambiguous assignments made. The significant finding in this regards are that, it is not necessary to assume lower than C(4V) symmetry for XMn(CO)(5) as has been done in previous consideration of some infrared spectrum of these compounds.