A series of nanocrystalline γ-alumina are synthesized by different procedures, namely, thermal decomposition method （sample A）, precipita-tion method （sample B） and sol-gel method using sucrose and hexadecyltrime...A series of nanocrystalline γ-alumina are synthesized by different procedures, namely, thermal decomposition method （sample A）, precipita-tion method （sample B） and sol-gel method using sucrose and hexadecyltrimethyl ammonium bromide （CTAB） as templates （samples C and D, respectively）. Textural and acidic properties of γ-alumina samples are characterized by XRD, N2 adsorption-desorption and NH3-TPD techniques. Vapor-phase dehydration of methanol into dimethyl ether is carried out over these samples. Among them, sample C shows the highest catalytic activity. NH3-TPD analysis reveals that the sample with smaller crystallite size possesses higher concentration of medium acidic sites and consequently higher catalytic activity. Thermal decomposition method leads to decrease in both surface area and moderate acidity, therefore it is the cause of lower catalytic activity.展开更多
Kinetic-catalytic spectrophotometric methods were proposed for the determination of trace amounts of vanadium element as vanadium（Ⅳ） and/or V（Ⅴ） ions. The vanadium（Ⅳ） as VO^2＋ ion and/or vanadium（Ⅴ） as VO...Kinetic-catalytic spectrophotometric methods were proposed for the determination of trace amounts of vanadium element as vanadium（Ⅳ） and/or V（Ⅴ） ions. The vanadium（Ⅳ） as VO^2＋ ion and/or vanadium（Ⅴ） as VO3^- ion showed a catalytic effect on the kinetic reactions between a color reagent such as methylthymol blue （MTB） or SPADNS and bromate in acidic media. The rate of decrease in the absorbance of the reagent MTB at 440 nm or SPADNS at 510 nm was proportional to concentration of V（Ⅳ） and/or V（Ⅴ） ions in the solution. The linear ranges for determination of vanadium were obtained in the range of 1.0-150 and 5.0-100.0 μg/L by the fixed-time and slope methods, respectively, with using MTB as reagent. In the presence of SPADNS as reagent, the calibration curves were made in the amplitude 1.0-200.0 and 5.0-150 μg/L of vanadium ion by the fixed-time and slope methods, respectively. Using fixed-time method, the limits of detection were obtained to be 0.5 and 0.7 μg/L of vanadium in the presence of MTB and SPADNS as reagents, respectively. Detection limits of vanadium by slope method and reagents of SPADNS and MTB were obtained to be 3.5 and 3.8 μg/L of vanadium, respectively. The proposed methods were applied successfully to determination of vanadium in synthetic and real samples.展开更多
Different multidisciplinary design optimization （MDO） problems are formulated and compared. Two MDO formulations are applied to a sounding rocket in order to optimize the performance of the rocket. In the MDO of the...Different multidisciplinary design optimization （MDO） problems are formulated and compared. Two MDO formulations are applied to a sounding rocket in order to optimize the performance of the rocket. In the MDO of the referred vehicle, three disciplines have been considered, which are trajectory, propulsion and aerodynamics. A special design structure matrix is developed to assist data exchange between disciplines. This design process uses response surface method （RSM） for multidisciplinary optimization of the rocket. The RSM is applied to the design in two categories： the propulsion model and the system level. In the propulsion model, RSM determines an approximate mathematical model of the engine output parameters as a function of design variables. In the system level, RSM fits a surface of objective function versus design variables. In the first MDO problem formulation, two design variables are selected to form propulsion discipline. In the second one, three new design variables from geometry are added and finally, an optimization method is applied to the response surface in the system level in order to find the best result. Application of the first developed multidisciplinary design optimization procedure increased accessible altitude （performance index） of the referred sounding rocket by twenty five percents and the second one twenty nine.展开更多
A new method for prediction of Gurney velocity of explosives is introduced in which energy output is correlated with the heat of detonation, the number of moles of gaseous products of detonation per gram of explosive ...A new method for prediction of Gurney velocity of explosives is introduced in which energy output is correlated with the heat of detonation, the number of moles of gaseous products of detonation per gram of explosive and the average molecular weight of gaseous products. It is assumed that the CHNO explosive reacts to form products composed of N2, CO, H2O, CO2, H2, O2 and C（s） as determined by the oxygen balance of the unreacted compound. Good agreement is obtained between measured and calculated values of Gurney velocity as compared to previous correlations which assumed the reaction products to consist of N2, H2O, CO2 and either C（s） or O2.展开更多
Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature.
During the multistep process of metastasis,cancer cells encounter various mechanical forces which make them deform drastically.Developing accurate in-silico models,capable of simulating the interactions between the me...During the multistep process of metastasis,cancer cells encounter various mechanical forces which make them deform drastically.Developing accurate in-silico models,capable of simulating the interactions between the mechanical forces and highly deformable cancer cells,can pave the way for the development of novel diagnostic and predictive methods for metastatic progression.Spring-network models of cancer cell,empowered by our recently proposed identification approach,promises a versatile numerical tool for developing experimentally validated models that can simulate complex interactions at cellular scale.Using this numerical tool,we presented spring-network models of breast cancer cells that can accurately replicate the experimental data of deformation behavior of the cells flowing in a fluidic domain and passing narrow constrictions comparable to microcapillary.First,using high-speed imaging,we experimentally studied the deformability of breast cancer cell lines with varying metastatic potential(MCF-7(less invasive),SKBR-3(medium-high invasive),and MDA-MB-231(highly invasive)in terms of their entry time to a constricted microfluidic channel.We observed that MDA-MB-231,that has the highest metastatic potential,is the most deformable cell among the three.Then,by focusing on this cell line,experimental measurements were expanded to two more constricted microchannel dimensions.The experimental deformability data in three constricted microchannel sizes for various cell sizes,enabled accurate identification of the unknown parameters of the spring-network model of the breast cancer cell line(MDA-MB-231).Our results show that the identifed parameters depend on the cell size,suggesting the need for a systematic procedure for identifying the size-dependent parameters of spring-network models of cells.As the numerical results show,the presented cell models can simulate the entry process of the cell into constricted channels with very good agreements with the measured experimental data.展开更多
The impacts of climate change on agriculture are still shadowed with uncertainty. However, climate change is expected to adversely affect Iran＇s agricultural practices through changes in precipitation, temperature an...The impacts of climate change on agriculture are still shadowed with uncertainty. However, climate change is expected to adversely affect Iran＇s agricultural practices through changes in precipitation, temperature and carbon dioxide fertilization. Therefore, adaptation of this sector to the increasing weather events is imperative. This study is aimed to document the likely impacts of climate change on Iran＇s agriculture and the current adaptation efforts made by government and farmers. The review of literature shows that changes in rainfall and water endowments will have significant impacts on crop yield, crops＇ water requirements and income and welfare of farm families. The extent of the changes in yield depends on the crop type, assumptions related to the CO2 fertilization effect, climate scenarios and adaptation abilities. On adaptation, the government＇s efforts have been distinguished in the improving agricultural productivity and irrigation development based on current technology, developing new technologies and policy reforms. Farmers＇ adaptive responses have also been identified. Some conclusions and recommendations are offered to increase the adaptive capacity of farmers and reduce negative impacts of climate change.展开更多
The wastewater with HMX and RDX was treated by photodegradation process in the presence of cadmium sulfide doped with copper as photocatalyst under UV and Vis irradiations.The influence on the degration of Cu% as dopa...The wastewater with HMX and RDX was treated by photodegradation process in the presence of cadmium sulfide doped with copper as photocatalyst under UV and Vis irradiations.The influence on the degration of Cu% as dopant in CdS/Cu nanoparticles,pH of solution,dosage of photocatalyst and concentration of explosives were studied.The XRD patterns and UV-Vis spectra were used to characterize the nanoparticle.Results show that the degradation efficiency for HMX and RDX wastewater reaches 85%-88% in the presence of Cd0.95Cu0.05S under 180 min UV irradiation.The dosage of 160.0 mg·L-1 of photocatalyst and the pH of 7 are the optimum.A gradual decrease in degradation at the first two cycles is seen.展开更多
Keto-RDX was obtained by one-step method with a certain amount of RDX as by-product.The effects of various parameters on high yield were studied.A simple analytical method was also introduced to determine simultaneous...Keto-RDX was obtained by one-step method with a certain amount of RDX as by-product.The effects of various parameters on high yield were studied.A simple analytical method was also introduced to determine simultaneously Keto-RDX/RDX mole ratio.Some important theoretical characterizations of Keto-RDX such as detonation performance at maximum nominal density and shock sensitivity were determined by new methods and compared with RDX.展开更多
The oxidation of organic compounds by sulfonated porous carbon and H2O2 was studied at room temperature. Alkyl and aryl sulfides were oxidized to the corresponding sulfoxides or sulfones in excellent yields. Secondary...The oxidation of organic compounds by sulfonated porous carbon and H2O2 was studied at room temperature. Alkyl and aryl sulfides were oxidized to the corresponding sulfoxides or sulfones in excellent yields. Secondary alcohols were also converted to the corresponding esters/lactones and aldehydes to methyl esters in good yields. Moreover,aliphatic tertiary amines and substituted pyridines were oxidized to N-oxides.展开更多
Yttria-stabilized zirconia(YSZ)thin nanocrystalline coatings at different substrate preheating temperatures were deposited via electron beam-physical vapour deposition(EB-PVD).Nanocrystalline ZrO_(2)-Y_(2)O_(3) was de...Yttria-stabilized zirconia(YSZ)thin nanocrystalline coatings at different substrate preheating temperatures were deposited via electron beam-physical vapour deposition(EB-PVD).Nanocrystalline ZrO_(2)-Y_(2)O_(3) was deposited on the bond coat in order to compensate for the coefficient of thermal expansion(CTE),which can be functionalized as a thermal barrier coating(TBC).The aim of this study was to evaluate mechanical properties with respect to adhesion of zirconia nanocrystalline’s top ceramic layer to the interfacial bond coat by utilizing micro and nano indentation tests.In the present paper,the structural studies were carried out using X-ray diffraction(XRD)analysis of coating content(8 mol%of Y_(2)O_(3)).The tetragonal phase of stabilized zirconia was observed.Field emission scanning electron microscopy(FESEM)and atomic force microscopy(AFM)were employed to characterize the coatings’morphology and microstructure.The mechanical behavior of ZrO_(2)-Y_(2)O_(3) thin films under point loading conditions was studied by nanoindentation using a Berkovich indenter with 130 nm tip radius.Therefore,adhesion of top coat to the interfacial underlying metallic bond coat known as MCrAlY(M=Ni,Co)was estimated according to the highest peak load tests;for a 120 mN peak load,the film manifested tolerable adhesion properties.Moreover,nanoindentation of ZrO_(2)-Y_(2)O_(3) nanostructure deposited at 1050℃substrate preheating temperature produced the highest hardness value of about 21.7 GPa.Vickers micro hardness was utilized with the aid of the Tabor equation in order to achieve deeper insight into the correlation between adhesion and deposition process parameters.展开更多
Tin sulfide nanoparticles(SnS -NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon(AC) and were investigated using field-emission scanning electron mi-croscopy(FE-SEM), transm...Tin sulfide nanoparticles(SnS -NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon(AC) and were investigated using field-emission scanning electron mi-croscopy(FE-SEM), transmission electron microscopy(TEM), X-ray diffraction, reflective ultravio-let-visible spectrophotometry, and spectrofluorimetry. Calculations based on the SEM and TEM images showed that the sizes of the SnS -NPs immobilized on the AC were 30–70 nm. The prepared nanocomposite was used as a heterogeneous Lewis acid catalyst for the three-components one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol at 80 ℃. The reactions were efficiently performed in the presence of the prepared catalyst in short reaction times, and gave the desired products in high yields. This catalyst can be easily recovered by simple filtration and recycled up to eight consecutive times without significant loss of its efficiency.展开更多
Poly（4-vinyl pyridine） supported nanoparticle of copper（Ⅰ） iodide is reported as a green and recyclable catalyst for the regioselective synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from benzyl halides,sodium...Poly（4-vinyl pyridine） supported nanoparticle of copper（Ⅰ） iodide is reported as a green and recyclable catalyst for the regioselective synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from benzyl halides,sodium azide and terminal alkynes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of its efficiency.展开更多
Effective communication and emotional support of parturient women improve the outcome of childbirth. Reduction in Duration of labor, cesarean rate, use of anesthesia, and 5 minute Apgar Score less than 7 can achieve. ...Effective communication and emotional support of parturient women improve the outcome of childbirth. Reduction in Duration of labor, cesarean rate, use of anesthesia, and 5 minute Apgar Score less than 7 can achieve. This study was a part of a large mixed method study during 2013-2014. In this qualitative study, in-depth interviews were conducted with 32 participants (16 mother and 16 midwife), using semi-structured interviews. Participants were recruited by pur-posive sampling with maximum diversity in terms of age, occupation, education and etc. Educational hospital of Arak University of Medical Sciences was considered as the setting. Each interview was conducted at a private and convenient location and took about 30 to 45 minutes. Interviews were audio taped and transcribed verbatim. Conventional content analysis was done for data analysis. Interviews continued until data saturation was obtained. Data were coded in MAXQDA software (version 11). The main category emerged as “outcome” of midwife-mother relationship. Facilitating childbirth, positive experience, mental health promotion and improvement in quality of life were derived as subcategories. Good midwife-mother relationship could promote positive outcome in labour. Results could assist midwives in providing holistic quality care to mothers during labour, thus providing positive consequence in child birth. Also, results could provide a framework and guidance for policymakers to create appropriate context for the midwife-mother relationship in maternity care.展开更多
Surfactant flooding is an important technique used to improve oil recovery from mature oil reservoirs due to minimizing the interfacial tension(IFT)between oil and water and/or altering the rock wettability toward wat...Surfactant flooding is an important technique used to improve oil recovery from mature oil reservoirs due to minimizing the interfacial tension(IFT)between oil and water and/or altering the rock wettability toward water-wet using various surfactant agents including cationic,anionic,non-ionic,and amphoteric varieties.In this study,two amino-acid based surfactants,named lauroyl arginine(L-Arg)and lauroyl cysteine(L-Cys),were synthesized and used to reduce the IFT of oil–water systems and alter the wettability of carbonate rocks,thus improving oil recovery from oil-wet carbonate reservoirs.The synthesized surfactants were characterized using Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses,and the critical micelle concentration(CMC)of surfactant solutions was determined using conductivity,pH,and turbidity techniques.Experimental results showed that the CMCs of L-Arg and L-Cys solutions were 2000 and 4500 ppm,respectively.It was found that using L-Arg and L-Cys solutions at their CMCs,the IFT and contact angle were reduced from 34.5 to 18.0 and15.4 mN/m,and from 144°to 78°and 75°,respectively.Thus,the L-Arg and L-Cys solutions enabled approximately 11.9%and 8.9%additional recovery of OOIP(original oil in place).It was identified that both amino-acid surfactants can be used to improve oil recovery due to their desirable effects on the EOR mechanisms at their CMC ranges.展开更多
The oxidative leaching causes to dissolve various impurities such as Fe, Cu, Pd, Se in copper anode slime. Organicextractant tri-butyl phosphate (TBP) was used to purify leach solution. Several parameters, such as TBP...The oxidative leaching causes to dissolve various impurities such as Fe, Cu, Pd, Se in copper anode slime. Organicextractant tri-butyl phosphate (TBP) was used to purify leach solution. Several parameters, such as TBP, HCl and chloride inorganicsalt concentrations were chosen in order to determine efficient state for impurities separation. Standard solvent extraction tests forextraction and separation of Au, Pd, Pt, Fe, Cu and Se were conducted with equal volume of aqueous and organic phases in batchexperiments. The effect of hydrochloric acid, organic phase and metals initial concentration were examined at ambient temperature. Itwas found that 0.25 mol/L TBP in the presence of 2.5 mol/L hydrochloric acid can cause high extraction of gold. Meanwhile, in theseconditions the extraction of other impurities is negligible. After extraction, pregnant organic phase was scrubbed by distilled waterand some impurities were removed. Finally, gold was stripped by sodium thiosulfate solution. The stripping solution does not haveany impurities. By adding H2SO4 to stripping solution containing Na2S2O2, SO2 gas is released and Au3+ ions could be reduced.展开更多
Aromatic aldehydes undergo cross-aldol condensation with ketones in the presence of carbon-based solid acid under solvent-free conditions to afford the corresponding α,β-unsaturated aldol products in excellent yield...Aromatic aldehydes undergo cross-aldol condensation with ketones in the presence of carbon-based solid acid under solvent-free conditions to afford the corresponding α,β-unsaturated aldol products in excellent yields. The catalyst is reusable several times without any decrease in the yield of the reactions.展开更多
AIM： To investigate the efficacy and tolerability of H pylori eradication in an omeprazole-based triple therapy with high and low dose of clarithromycin and amoxicillin. METHODS： One hundred and sixty H pylori posi...AIM： To investigate the efficacy and tolerability of H pylori eradication in an omeprazole-based triple therapy with high and low dose of clarithromycin and amoxicillin. METHODS： One hundred and sixty H pylori positive patients were randomly assigned to two groups based on the following 2 wk investigation; （1） group A or low-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 250 mg b.i.d and amoxicillin 500 mg b.i.d; and （2） group B or high-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 500 mg b.i.d and amoxicillin 1000 mg b.i.d. During the study Hpylori status was assessed by histology and rapid urease test prior and by 13C-urea breath test 6 wk after the therapy. Standard questionnaires were administered to determine the compliance to treatment and possible adverse events of therapy. Data were subject to x^2 to compare the eradication rates in the two groups. The significant level of 95% （P ≤ 0.05） was considered statistically different. RESULTS： We found that the per-protocol eradication rate was 88% （68/77） in group A, and 89% （67/75） in group B. The intension-to-treat eradication rate was 85% （68/80） in group A and 83.75% （67180） in group B. Overall adverse events were 26% in group A and 31% in group B. The adverse events were generally mild in nature and tolerated well in both groups with a compliance of 98% in group A vs 96% in group B. CONCLUSION： The omeprazole-based low dose regimen of darithromycin and amoxicillin for two weeks in Hpylori eradication is as effective as high dose regimen in Iranian population.展开更多
In this paper, the influence of temperature on the intracavity optical parametric oscillator（IOPO） is investigated by using the stimulated temperature-dependent emission cross section of laser crystal. The rate equa...In this paper, the influence of temperature on the intracavity optical parametric oscillator（IOPO） is investigated by using the stimulated temperature-dependent emission cross section of laser crystal. The rate equations under plane wave approximation have been used for simulation of signal output pulse. Results show that the signal output pulse width is decreased by increasing the laser crystal temperature. Also, the signal output energy is increased by the increasing of the laser crystal temperature. The simulation results for IOPO based on Nd：YAG and Nd：YVO_4, show that the signal pulse energies are increased by 3.2 and 5.6 times respectively when the laser crystal temperature increased from 15℃ to 300℃. The presented model indicates that the temperature sensitivity of Nd：YVO_4-based IOPOs is more than that of Nd：YAG-based IOPOs which is expected from a physical point of view.展开更多
基金supported by the Petrochemical Research & Technology Company of National Petrochemical Company in Iran
文摘A series of nanocrystalline γ-alumina are synthesized by different procedures, namely, thermal decomposition method （sample A）, precipita-tion method （sample B） and sol-gel method using sucrose and hexadecyltrimethyl ammonium bromide （CTAB） as templates （samples C and D, respectively）. Textural and acidic properties of γ-alumina samples are characterized by XRD, N2 adsorption-desorption and NH3-TPD techniques. Vapor-phase dehydration of methanol into dimethyl ether is carried out over these samples. Among them, sample C shows the highest catalytic activity. NH3-TPD analysis reveals that the sample with smaller crystallite size possesses higher concentration of medium acidic sites and consequently higher catalytic activity. Thermal decomposition method leads to decrease in both surface area and moderate acidity, therefore it is the cause of lower catalytic activity.
文摘Kinetic-catalytic spectrophotometric methods were proposed for the determination of trace amounts of vanadium element as vanadium（Ⅳ） and/or V（Ⅴ） ions. The vanadium（Ⅳ） as VO^2＋ ion and/or vanadium（Ⅴ） as VO3^- ion showed a catalytic effect on the kinetic reactions between a color reagent such as methylthymol blue （MTB） or SPADNS and bromate in acidic media. The rate of decrease in the absorbance of the reagent MTB at 440 nm or SPADNS at 510 nm was proportional to concentration of V（Ⅳ） and/or V（Ⅴ） ions in the solution. The linear ranges for determination of vanadium were obtained in the range of 1.0-150 and 5.0-100.0 μg/L by the fixed-time and slope methods, respectively, with using MTB as reagent. In the presence of SPADNS as reagent, the calibration curves were made in the amplitude 1.0-200.0 and 5.0-150 μg/L of vanadium ion by the fixed-time and slope methods, respectively. Using fixed-time method, the limits of detection were obtained to be 0.5 and 0.7 μg/L of vanadium in the presence of MTB and SPADNS as reagents, respectively. Detection limits of vanadium by slope method and reagents of SPADNS and MTB were obtained to be 3.5 and 3.8 μg/L of vanadium, respectively. The proposed methods were applied successfully to determination of vanadium in synthetic and real samples.
文摘Different multidisciplinary design optimization （MDO） problems are formulated and compared. Two MDO formulations are applied to a sounding rocket in order to optimize the performance of the rocket. In the MDO of the referred vehicle, three disciplines have been considered, which are trajectory, propulsion and aerodynamics. A special design structure matrix is developed to assist data exchange between disciplines. This design process uses response surface method （RSM） for multidisciplinary optimization of the rocket. The RSM is applied to the design in two categories： the propulsion model and the system level. In the propulsion model, RSM determines an approximate mathematical model of the engine output parameters as a function of design variables. In the system level, RSM fits a surface of objective function versus design variables. In the first MDO problem formulation, two design variables are selected to form propulsion discipline. In the second one, three new design variables from geometry are added and finally, an optimization method is applied to the response surface in the system level in order to find the best result. Application of the first developed multidisciplinary design optimization procedure increased accessible altitude （performance index） of the referred sounding rocket by twenty five percents and the second one twenty nine.
文摘A new method for prediction of Gurney velocity of explosives is introduced in which energy output is correlated with the heat of detonation, the number of moles of gaseous products of detonation per gram of explosive and the average molecular weight of gaseous products. It is assumed that the CHNO explosive reacts to form products composed of N2, CO, H2O, CO2, H2, O2 and C（s） as determined by the oxygen balance of the unreacted compound. Good agreement is obtained between measured and calculated values of Gurney velocity as compared to previous correlations which assumed the reaction products to consist of N2, H2O, CO2 and either C（s） or O2.
文摘Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature.
基金supported by the Natural Sciences and Engineering Research Council of Canada(RGPIN-2020-05522&RGPIN-2020-00428).
文摘During the multistep process of metastasis,cancer cells encounter various mechanical forces which make them deform drastically.Developing accurate in-silico models,capable of simulating the interactions between the mechanical forces and highly deformable cancer cells,can pave the way for the development of novel diagnostic and predictive methods for metastatic progression.Spring-network models of cancer cell,empowered by our recently proposed identification approach,promises a versatile numerical tool for developing experimentally validated models that can simulate complex interactions at cellular scale.Using this numerical tool,we presented spring-network models of breast cancer cells that can accurately replicate the experimental data of deformation behavior of the cells flowing in a fluidic domain and passing narrow constrictions comparable to microcapillary.First,using high-speed imaging,we experimentally studied the deformability of breast cancer cell lines with varying metastatic potential(MCF-7(less invasive),SKBR-3(medium-high invasive),and MDA-MB-231(highly invasive)in terms of their entry time to a constricted microfluidic channel.We observed that MDA-MB-231,that has the highest metastatic potential,is the most deformable cell among the three.Then,by focusing on this cell line,experimental measurements were expanded to two more constricted microchannel dimensions.The experimental deformability data in three constricted microchannel sizes for various cell sizes,enabled accurate identification of the unknown parameters of the spring-network model of the breast cancer cell line(MDA-MB-231).Our results show that the identifed parameters depend on the cell size,suggesting the need for a systematic procedure for identifying the size-dependent parameters of spring-network models of cells.As the numerical results show,the presented cell models can simulate the entry process of the cell into constricted channels with very good agreements with the measured experimental data.
文摘The impacts of climate change on agriculture are still shadowed with uncertainty. However, climate change is expected to adversely affect Iran＇s agricultural practices through changes in precipitation, temperature and carbon dioxide fertilization. Therefore, adaptation of this sector to the increasing weather events is imperative. This study is aimed to document the likely impacts of climate change on Iran＇s agriculture and the current adaptation efforts made by government and farmers. The review of literature shows that changes in rainfall and water endowments will have significant impacts on crop yield, crops＇ water requirements and income and welfare of farm families. The extent of the changes in yield depends on the crop type, assumptions related to the CO2 fertilization effect, climate scenarios and adaptation abilities. On adaptation, the government＇s efforts have been distinguished in the improving agricultural productivity and irrigation development based on current technology, developing new technologies and policy reforms. Farmers＇ adaptive responses have also been identified. Some conclusions and recommendations are offered to increase the adaptive capacity of farmers and reduce negative impacts of climate change.
文摘The wastewater with HMX and RDX was treated by photodegradation process in the presence of cadmium sulfide doped with copper as photocatalyst under UV and Vis irradiations.The influence on the degration of Cu% as dopant in CdS/Cu nanoparticles,pH of solution,dosage of photocatalyst and concentration of explosives were studied.The XRD patterns and UV-Vis spectra were used to characterize the nanoparticle.Results show that the degradation efficiency for HMX and RDX wastewater reaches 85%-88% in the presence of Cd0.95Cu0.05S under 180 min UV irradiation.The dosage of 160.0 mg·L-1 of photocatalyst and the pH of 7 are the optimum.A gradual decrease in degradation at the first two cycles is seen.
文摘Keto-RDX was obtained by one-step method with a certain amount of RDX as by-product.The effects of various parameters on high yield were studied.A simple analytical method was also introduced to determine simultaneously Keto-RDX/RDX mole ratio.Some important theoretical characterizations of Keto-RDX such as detonation performance at maximum nominal density and shock sensitivity were determined by new methods and compared with RDX.
基金Supported by the Malek-Ashtar University of Technology
文摘The oxidation of organic compounds by sulfonated porous carbon and H2O2 was studied at room temperature. Alkyl and aryl sulfides were oxidized to the corresponding sulfoxides or sulfones in excellent yields. Secondary alcohols were also converted to the corresponding esters/lactones and aldehydes to methyl esters in good yields. Moreover,aliphatic tertiary amines and substituted pyridines were oxidized to N-oxides.
文摘Yttria-stabilized zirconia(YSZ)thin nanocrystalline coatings at different substrate preheating temperatures were deposited via electron beam-physical vapour deposition(EB-PVD).Nanocrystalline ZrO_(2)-Y_(2)O_(3) was deposited on the bond coat in order to compensate for the coefficient of thermal expansion(CTE),which can be functionalized as a thermal barrier coating(TBC).The aim of this study was to evaluate mechanical properties with respect to adhesion of zirconia nanocrystalline’s top ceramic layer to the interfacial bond coat by utilizing micro and nano indentation tests.In the present paper,the structural studies were carried out using X-ray diffraction(XRD)analysis of coating content(8 mol%of Y_(2)O_(3)).The tetragonal phase of stabilized zirconia was observed.Field emission scanning electron microscopy(FESEM)and atomic force microscopy(AFM)were employed to characterize the coatings’morphology and microstructure.The mechanical behavior of ZrO_(2)-Y_(2)O_(3) thin films under point loading conditions was studied by nanoindentation using a Berkovich indenter with 130 nm tip radius.Therefore,adhesion of top coat to the interfacial underlying metallic bond coat known as MCrAlY(M=Ni,Co)was estimated according to the highest peak load tests;for a 120 mN peak load,the film manifested tolerable adhesion properties.Moreover,nanoindentation of ZrO_(2)-Y_(2)O_(3) nanostructure deposited at 1050℃substrate preheating temperature produced the highest hardness value of about 21.7 GPa.Vickers micro hardness was utilized with the aid of the Tabor equation in order to achieve deeper insight into the correlation between adhesion and deposition process parameters.
基金Islamic Azad University, Gachsaran Branchthe Research Council of Yasouj University for financial support
文摘Tin sulfide nanoparticles(SnS -NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon(AC) and were investigated using field-emission scanning electron mi-croscopy(FE-SEM), transmission electron microscopy(TEM), X-ray diffraction, reflective ultravio-let-visible spectrophotometry, and spectrofluorimetry. Calculations based on the SEM and TEM images showed that the sizes of the SnS -NPs immobilized on the AC were 30–70 nm. The prepared nanocomposite was used as a heterogeneous Lewis acid catalyst for the three-components one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol at 80 ℃. The reactions were efficiently performed in the presence of the prepared catalyst in short reaction times, and gave the desired products in high yields. This catalyst can be easily recovered by simple filtration and recycled up to eight consecutive times without significant loss of its efficiency.
文摘Poly（4-vinyl pyridine） supported nanoparticle of copper（Ⅰ） iodide is reported as a green and recyclable catalyst for the regioselective synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from benzyl halides,sodium azide and terminal alkynes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of its efficiency.
文摘Effective communication and emotional support of parturient women improve the outcome of childbirth. Reduction in Duration of labor, cesarean rate, use of anesthesia, and 5 minute Apgar Score less than 7 can achieve. This study was a part of a large mixed method study during 2013-2014. In this qualitative study, in-depth interviews were conducted with 32 participants (16 mother and 16 midwife), using semi-structured interviews. Participants were recruited by pur-posive sampling with maximum diversity in terms of age, occupation, education and etc. Educational hospital of Arak University of Medical Sciences was considered as the setting. Each interview was conducted at a private and convenient location and took about 30 to 45 minutes. Interviews were audio taped and transcribed verbatim. Conventional content analysis was done for data analysis. Interviews continued until data saturation was obtained. Data were coded in MAXQDA software (version 11). The main category emerged as “outcome” of midwife-mother relationship. Facilitating childbirth, positive experience, mental health promotion and improvement in quality of life were derived as subcategories. Good midwife-mother relationship could promote positive outcome in labour. Results could assist midwives in providing holistic quality care to mothers during labour, thus providing positive consequence in child birth. Also, results could provide a framework and guidance for policymakers to create appropriate context for the midwife-mother relationship in maternity care.
文摘Surfactant flooding is an important technique used to improve oil recovery from mature oil reservoirs due to minimizing the interfacial tension(IFT)between oil and water and/or altering the rock wettability toward water-wet using various surfactant agents including cationic,anionic,non-ionic,and amphoteric varieties.In this study,two amino-acid based surfactants,named lauroyl arginine(L-Arg)and lauroyl cysteine(L-Cys),were synthesized and used to reduce the IFT of oil–water systems and alter the wettability of carbonate rocks,thus improving oil recovery from oil-wet carbonate reservoirs.The synthesized surfactants were characterized using Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses,and the critical micelle concentration(CMC)of surfactant solutions was determined using conductivity,pH,and turbidity techniques.Experimental results showed that the CMCs of L-Arg and L-Cys solutions were 2000 and 4500 ppm,respectively.It was found that using L-Arg and L-Cys solutions at their CMCs,the IFT and contact angle were reduced from 34.5 to 18.0 and15.4 mN/m,and from 144°to 78°and 75°,respectively.Thus,the L-Arg and L-Cys solutions enabled approximately 11.9%and 8.9%additional recovery of OOIP(original oil in place).It was identified that both amino-acid surfactants can be used to improve oil recovery due to their desirable effects on the EOR mechanisms at their CMC ranges.
文摘The oxidative leaching causes to dissolve various impurities such as Fe, Cu, Pd, Se in copper anode slime. Organicextractant tri-butyl phosphate (TBP) was used to purify leach solution. Several parameters, such as TBP, HCl and chloride inorganicsalt concentrations were chosen in order to determine efficient state for impurities separation. Standard solvent extraction tests forextraction and separation of Au, Pd, Pt, Fe, Cu and Se were conducted with equal volume of aqueous and organic phases in batchexperiments. The effect of hydrochloric acid, organic phase and metals initial concentration were examined at ambient temperature. Itwas found that 0.25 mol/L TBP in the presence of 2.5 mol/L hydrochloric acid can cause high extraction of gold. Meanwhile, in theseconditions the extraction of other impurities is negligible. After extraction, pregnant organic phase was scrubbed by distilled waterand some impurities were removed. Finally, gold was stripped by sodium thiosulfate solution. The stripping solution does not haveany impurities. By adding H2SO4 to stripping solution containing Na2S2O2, SO2 gas is released and Au3+ ions could be reduced.
文摘Aromatic aldehydes undergo cross-aldol condensation with ketones in the presence of carbon-based solid acid under solvent-free conditions to afford the corresponding α,β-unsaturated aldol products in excellent yields. The catalyst is reusable several times without any decrease in the yield of the reactions.
文摘AIM： To investigate the efficacy and tolerability of H pylori eradication in an omeprazole-based triple therapy with high and low dose of clarithromycin and amoxicillin. METHODS： One hundred and sixty H pylori positive patients were randomly assigned to two groups based on the following 2 wk investigation; （1） group A or low-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 250 mg b.i.d and amoxicillin 500 mg b.i.d; and （2） group B or high-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 500 mg b.i.d and amoxicillin 1000 mg b.i.d. During the study Hpylori status was assessed by histology and rapid urease test prior and by 13C-urea breath test 6 wk after the therapy. Standard questionnaires were administered to determine the compliance to treatment and possible adverse events of therapy. Data were subject to x^2 to compare the eradication rates in the two groups. The significant level of 95% （P ≤ 0.05） was considered statistically different. RESULTS： We found that the per-protocol eradication rate was 88% （68/77） in group A, and 89% （67/75） in group B. The intension-to-treat eradication rate was 85% （68/80） in group A and 83.75% （67180） in group B. Overall adverse events were 26% in group A and 31% in group B. The adverse events were generally mild in nature and tolerated well in both groups with a compliance of 98% in group A vs 96% in group B. CONCLUSION： The omeprazole-based low dose regimen of darithromycin and amoxicillin for two weeks in Hpylori eradication is as effective as high dose regimen in Iranian population.
文摘In this paper, the influence of temperature on the intracavity optical parametric oscillator（IOPO） is investigated by using the stimulated temperature-dependent emission cross section of laser crystal. The rate equations under plane wave approximation have been used for simulation of signal output pulse. Results show that the signal output pulse width is decreased by increasing the laser crystal temperature. Also, the signal output energy is increased by the increasing of the laser crystal temperature. The simulation results for IOPO based on Nd：YAG and Nd：YVO_4, show that the signal pulse energies are increased by 3.2 and 5.6 times respectively when the laser crystal temperature increased from 15℃ to 300℃. The presented model indicates that the temperature sensitivity of Nd：YVO_4-based IOPOs is more than that of Nd：YAG-based IOPOs which is expected from a physical point of view.
