The synthesis and characterization of N,N＇-bis（salicylidene） ethylenediamine, Salen said that were carried out. The behavior of this ligand has been studied in solution in solvent homogeneous and heterogeneous syst...The synthesis and characterization of N,N＇-bis（salicylidene） ethylenediamine, Salen said that were carried out. The behavior of this ligand has been studied in solution in solvent homogeneous and heterogeneous systems in sulphate medium. The use of pH-metric titration, GRAN and JOB＇s methods have permitted the determination of different parameters governing the behavior of Salen in solution such as the acidity constant, the stability constant, the nature of the interaction solvent-solute, the solvation number, the stoichiometry of extracted complex etc.. Then the extraction of the Salen was finally undertaken to words the copper （II） sulfate medium. The pH of complexation, extraction time, the number of protons exchanged and the number of ligands have been finally determined.展开更多
In this work, a new microextraction method termed ionic liquid based dispersive liquid-liquid microextraction （IL-DLLME） was demonstrated for the extraction of 2-methylaniline, 4-chloroaniline, 1-naphthylamine and 4...In this work, a new microextraction method termed ionic liquid based dispersive liquid-liquid microextraction （IL-DLLME） was demonstrated for the extraction of 2-methylaniline, 4-chloroaniline, 1-naphthylamine and 4-aminobiphenyl in aqueous matrices. After extraction the ionic liquid （IL） phase was injected directly into the high performance liquid chromatography （HPLC） system for determination. Some parameters that might affect the extraction efficiency were optimized. Under the optimum conditions, good linear relationship, sensitivity and reproducibility were obtained. The limits of detection （LOD, S/N = 3） for the four analytes were in the range of 0.45-2.6 μg L^-1. The relative standard deviations （R.S.D., n = 6） were in the range of 6.2-9.8%. This method was applied for the analysis of the real water samples. The recoveries ranged from 93.4 to 106.4%. The main advantages of the method are high speed, high recovery, good repeatability and volatile organic solvent-free.展开更多
A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） ...A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.展开更多
Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet gri...Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2 and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.展开更多
The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baf...The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baffles in a mechanically agitated vessel is to ensure even distribution,reduce settler turbulence,promote the stability of power drawn by the impeller and to prevent swirling and vortexing of liquid,thus,greatly improving the mixing of liquid.The insertion of the appropriate number of baffles clearly improves the extent of liquid mixing.However,excessive baffling would interrupt liquid mixing and lengthen the mixing time.Computational fluid dynamics(CFD) provides a tool for determining detailed information on fluid flow(hydrodynamics) which is necessary for modeling subprocesses in mixer settler.A total of 54 final CFD runs were carried out representing different combinations of variables like number of baffles,density and impeller speed.CFD data shows that amount of separation increases with increasing baffles number and decreasing impeller speed.展开更多
The extractive desulfurization of a model gaso- line containing several alkyl thiols and aromatic thiophenic compounds was investigated using two imidazolium-based ionic liquids （ILs）, 1-butyl-3-methylimidazolium te...The extractive desulfurization of a model gaso- line containing several alkyl thiols and aromatic thiophenic compounds was investigated using two imidazolium-based ionic liquids （ILs）, 1-butyl-3-methylimidazolium tetrachloroaluminate, and 1-octyl-3-methylimidazolium te- trafluoroborate, as extractants. A fractional factorial design of experiments was employed to evaluate the effects and possible interactions of several process variables. Analysis of variance tests indicated that the number of extraction steps and the IL/gasoline volume ratio were of statistically highly significant, but none of the interactions were significant. The results showed that the desulfurization efficiency of the model gasoline by the ILs could reach 95.2 % under the optimal conditions. The optimized conditions were applied to study the extraction of thiophenic compounds in model gasoline and several real gasoline samples; the following order was observed in their separation： benzothio- phenc 〉 thiophcne 〉 3-methylthiophene 〉 2-methylthiophene, with 96.1% removal efficiency for benzothiophene. The IL extraction was successfully applied as a complementary process to the adsorptive desulfurization with acti- vated Raney nickel and acetonitrile solvent. The results indicated that the adsorptive process combined with IL extraction could provide high efficiency and selectivity, which can be regarded as a promising energy efficient desulfurization strategy for production of low-sulfur gasoline.展开更多
OBJECTIVE： The stable quality of Chinese herbal medicines is a critical factor for their reliable clinical efficiency. An improved liquid-liquid extraction procedure and a liquid chromatographic method were developed...OBJECTIVE： The stable quality of Chinese herbal medicines is a critical factor for their reliable clinical efficiency. An improved liquid-liquid extraction procedure and a liquid chromatographic method were developed to simultaneously analyze five anthraquinones （aloe-emodin, rhein, emodin, chrysophanol and physcion） in a Chinese traditional hospital preparation, Fuyankang mixture, in order to quantitatively control its quality in a more effective way. METHODS： A more economical and repeatable extraction procedure based on conventional liquid-liquid extraction technique was developed and used to extract five marker components in Fuyankang mixture. These anthraquinones were separated in less than 20 min on a C18 column with methanol and 0.1% phosphoric acid （88：12, v/v） as mobile phase. The method was validated for specificity, precision, spiked recovery and stability. RESULTS： Compared to conventional liquid-liquid extraction, the improved liquid-liquid extraction was found to be more effective for simultaneous extraction of anthraquinones from an aqueous Chinese herbal preparation, especially for hydrophobic compounds. The improved extraction method was successfully applied to determine the content of five marker components in Fuyankang mixture by the means of reverse phase high-performance liquid chromatography. CONCLUSION： The improved extraction procedure may be suitable for routine quality control of Fuyankanq mixture and other traditional preparations at city-level hospitals in China.展开更多
The immiscible Cu-Fe alloy was characterized by a metastable miscibility gap.With the addition element Zr,the miscibility gap can be extended into the Cu-Fe-Zr ternary system.The effect of the atomic ratio of Cu to Fe...The immiscible Cu-Fe alloy was characterized by a metastable miscibility gap.With the addition element Zr,the miscibility gap can be extended into the Cu-Fe-Zr ternary system.The effect of the atomic ratio of Cu to Fe and Zr content on the behavior of liquid-liquid phase separation was studied.The results show that liquid-liquid phase separation into Cu-rich and Fe-rich liquids took place in the as-quenched Cu-Fe-Zr alloy.A glassy structure with nanoscale phase separation was obtained in the as-quenched(Cu0.5Fe0.5)40Zr60 alloy sample,exhibiting a homogeneous distribution of glassy Cu-rich nanoparticles in glassy Fe-rich matrix.The microstructural evolution and the competitive mechanism of phase formation in the rapidly solidified Cu-Fe-Zr system were discussed in detail.Moreover,the electrical property of the as-quenched Cu-Fe-Zr alloy samples was examined.It displays an abnormal change of electrical resistivity upon temperature in the nanoscale-phase-separation metallic glass.The crystallization behavior of such metallic glass has been discussed.展开更多
A new technique for ice slurry production was explored. Multiple small water-drops were formed in another immiscible chilled liquid by a single-nozzled atomizer and frozen in the fluidized bed by direct contact heat t...A new technique for ice slurry production was explored. Multiple small water-drops were formed in another immiscible chilled liquid by a single-nozzled atomizer and frozen in the fluidized bed by direct contact heat transfer. Experiments were conducted to investigate the dynamic behaviors of the ice crystal making system. The results demonstrate that the ice crystals could be produced continuously and stably in the vertical bed with the circulating coolant of initial temperature below -5℃. The size distribution of the ice crystals appears non-uniform, but is more similar and more uniform at lower oil flow rate. The mean ice crystal size rests seriously with the jet velocity and the oil flow rate. It decreases with decreasing the oil flow rate, and reaches the maximum at an intermediate jet velocity at about 16.5 m.s y. The ice crystal size is also closely related to the phenomenon of drop-coalescing, which can be alleviated considerably by reducing the flow rate or lowering the temperature of the carrier oil. However, optimization of liquid-liquid atomization is a more effective approach to produce fine ice crystals of desired size.展开更多
Liners in wet ball mill for mineral processing industry must bear abrasive wear and corrosive wear, and consequently, the service life of the liner made from traditional materials, such as Hadfield steel and alloyed s...Liners in wet ball mill for mineral processing industry must bear abrasive wear and corrosive wear, and consequently, the service life of the liner made from traditional materials, such as Hadfield steel and alloyed steels, is typically less than ten months. Bimetal liner, made from high Cr white cast iron and carbon steel, has been successfully developed by using liquid-liquid composite lost foam casting process. The microstructure and interface of the composite were analyzed using optical microscope, SEM, EDX and XRD. Micrographs indicate that the boundary of bimetal combination regions is staggered like dogtooth, two liquid metals are not mixed, and the interface presents excellent metallurgical bonding state. After heat treatment, the composite liner specimens have shown excellent properties, including hardness 〉 61 HRC, fracture toughness ak 〉16.5 J.cm2 and bending strength 〉1,600 MPa. Wear comparison was made between the bimetal composite liner and alloyed steel liner in an industrial hematite ball mill of WISCO, and the results of eight-month test in wet grinding environment have proved that the service life of the bimetal composite liner is three times as long as that of the alloyed steel liner.展开更多
The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Vali-dations of analytical methods for MT residue in food and the results obtained have become indispensable. Th...The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Vali-dations of analytical methods for MT residue in food and the results obtained have become indispensable. The high perfor-mance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy)at the 1, 5 and 10mg kg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation(RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10%for muscle tissue. The limit of detection was 0.05 mg kg-1.展开更多
Crusher hammers for the mineral processing industry must meet the demands of both high wear resistance at the hammer head and high impact toughness at the hammer handle. The crusher hammers made of Hadfield steel have...Crusher hammers for the mineral processing industry must meet the demands of both high wear resistance at the hammer head and high impact toughness at the hammer handle. The crusher hammers made of Hadfield steel have typical y low service life of less than 40 hours. To solve the problem, a kind of bimetal crusher hammers made of high chromium cast iron （HCCI） and low al oy steel （LAS） has been successful y developed by using liquid-liquid composite casting. The microstructure and composite interface bonding was analyzed using optical microscope, SEM, EDX and XRD. Micrographs indicate that the composite interface is metal urgical y bonded with a zigzag shape across the boundary and without unbound region or void. After heat treatment, the composite hammers have shown excellent properties. The hardness of HCCI is at least 63 HRC and its αk is greater than 3.5 J？cm-2; the hardness of LAS is greater than 35 HRC and its αk is no less than 80 J？cm-2. Diffusion of elements takes place at the interface and forms a transition region. The micro hardness increases from LAS to the interface and then to HCCI. Wear comparison was made separately between the bimetal composite hammer and a Hadfield steel hammer in two quarries of Jilin province and Liaoning province. The results showed that the liquid-liquid bimetal composite hammers did not have the fal ing off of hammer head or impact fracture phenomenon, and their service life was 3.75 times as long as that of the Hadfield steel hammers.展开更多
A novel,simple,rapid,efficient and environment-friendly method for the determination of trace copper in cereal samples was developed by using dispersive liquid-liquid microextraction based on solidification of floatin...A novel,simple,rapid,efficient and environment-friendly method for the determination of trace copper in cereal samples was developed by using dispersive liquid-liquid microextraction based on solidification of floating organic drop（DLLME-SFO） followed by flame atomic absorption spectrometry.In the DLLME-SFO,copper was complexed with 8-hydroxy quinoline and extracted into a small volume of 1-dodecanol,which is of low density,low toxicity and proper melting point near room temperature. The experimental parameters affecting the extraction efficiency were investigated and optimized.Under the optimum conditions, the calibration graph exhibited linearity over the range of 0.5—500 ng/mL with the correlation coefficient（r） of 0.9996.The enrichment factor was 122 and the limit of detection was 0.1 ng/mL.The method was applied to the determination of copper in the complex matrix samples such as rice and millet with the recoveries for the spiked samples at 5.0 and 10.0 u,g/g falling in the range of 92.0-98.0%and the relative standard deviation of 3.9-5.7%.展开更多
A key to tackling the coronavirus disease 2019(COVID-19)pandemic is to understand how severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)manages to outsmart host antiviral defense mechanisms.Stress granules(S...A key to tackling the coronavirus disease 2019(COVID-19)pandemic is to understand how severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)manages to outsmart host antiviral defense mechanisms.Stress granules(SGs),which are assembled during viral infection and function to sequester host and viral m RNAs and proteins,are part of the antiviral responses.Here,we show that the SARS-Co V-2 nucleocapsid(N)protein,an RNA binding protein essential for viral production,interacted with RasGTPase-activating protein SH3-domain-binding protein(G3 BP)and disrupted SG assembly,both of which require intrinsically disordered region1(IDR1)in N protein.The N protein partitioned into SGs through liquid-liquid phase separation with G3 BP,and blocked the interaction of G3 BP1 with other SG-related proteins.Moreover,the N protein domains important for phase separation with G3 BP and SG disassembly were required for SARS-Co V-2 viral production.We propose that N protein-mediated SG disassembly is crucial for SARS-Co V-2 production.展开更多
Primary breakup in a liquid-liquid pintle injector element at different radial jet velocities is investigated to elucidate the impingement morphology,the formation of primary breakup spray half cone angle,the pressure...Primary breakup in a liquid-liquid pintle injector element at different radial jet velocities is investigated to elucidate the impingement morphology,the formation of primary breakup spray half cone angle,the pressure distribution,the liquid diameter distribution,and the liquid velocity distribution.With a sufficient mesh resolution,the liquid morphology can be captured in a physically sound way.A mushroom tip is triggered by a larger radial jet velocity and breakup happens at the tip edge first.Different kinds of ligament breakup patterns due to aerodynamic force and surface tension are captured on the axial sheet.A high pressure core is spotted at the impinging point region.A larger radial jet velocity can feed more disturbances into the impinging point and the axial sheet,generate stronger vortices to promote the breakup process at a longer distance,and form a larger spray half cone angle.Because of the re-collision phenomenon the axial sheet diameter does not decrease monotonically.The inner rim on the axial sheet shows a larger diameter magnitude and a lower velocity magnitude due to surface tension.This paper is expected to provide a reference for the optimum design of a liquid-liquid pintle injector.展开更多
A rapid and sensitive liquid chromatography-tandem mass spectrometric（LC-MS/MS） assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma.Furo...A rapid and sensitive liquid chromatography-tandem mass spectrometric（LC-MS/MS） assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma.Furosemide was used as an internal standard.Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether.The reconstituted samples were chromatographed on a Zorbax SB-C;8 column by using a mixture of 5 mM ammonium acetate buffer and acetonitrile（20:80,v/v） as the mobile phase at a flow rate of 0.8 mL/min.The calibration curve obtained was linear（r≥0.99） over the concentration range of 0.50-600.29 ng/mL for pravastatin and 20.07-2012.00 ng/mL for aspirin.Method validation was performed as per FDA guidelines and the results met the acceptance criteria.A run time of 2.0 min for each sample made it possible to analyze more than 400 human plasma samples per day.The proposed method was found to be applicable to clinical studies.展开更多
Two sample preparation methods were introduced and compared in this paper to establish a simple,quick and exact analysis of geosmin and 2-methylisoborneol.LC-18 column was employed in solid phase extraction(SPE),1.0 m...Two sample preparation methods were introduced and compared in this paper to establish a simple,quick and exact analysis of geosmin and 2-methylisoborneol.LC-18 column was employed in solid phase extraction(SPE),1.0 mL of hexane was adopted in liquid-liquid extraction(LLE),and the extracts were analyzed by gas chromatograph mass spectrum(GCMS)in selected ion mode.Mean recoveries of SPE were low for 2-methylisoborneol(2-MIB)and geosmin(GSM)with values below 50%.For LLE,the recoveries were satisfyingly above 50%for 2-MIB and 80%for GSM.Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB.A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer,there was a serious odor problem induced by a high concentration of 2-MIB.The highest concentration of 152.82 ng/L appeared in July in raw water,while GSM flocculation was minimal with concentrations below odor threshold.展开更多
A novel process for separation of red （Y2O3： Eu^3＋）, blue （Sr, Ca, Ba）10（PO4）6Cl2： Eu^2＋ and green （LaPO4： Tb^3＋, Ce^3＋） fine tricolor phosphor powders was established. First, the green phosphor was ext...A novel process for separation of red （Y2O3： Eu^3＋）, blue （Sr, Ca, Ba）10（PO4）6Cl2： Eu^2＋ and green （LaPO4： Tb^3＋, Ce^3＋） fine tricolor phosphor powders was established. First, the green phosphor was extracted and separated from three phosphor mixtures in heptane/DMF（N, N-Dimethylformamide） system using stearylamine or laurylamine （DDA） as the cationic surfactant. Then, after being treated with 99.5% ethanol, the blue and red phosphors could be separated in Heptane/DMF system in presence of 1-octanesulfonic acid sodium salt as the anionic surfactant. Satisfactory separation results have been achieved through two steps extractions with their artificial mixtures. The grades and recovery of separated products reached respectively as follows： red product was 95.3% and 90.9%, blue product was 90.0% and 95.2%, and green product was 92.2% and 91.8%.展开更多
A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavo...A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavor/odor compounds, included geosmin, 2- methylisobomeol （MIB）, 2-isobutyl-3-methyoxypyrazine （IBMP）, and 2-isopropyl-3-methoxypyrazine （IPMP）. Using this method, a single sample can be extracted within minutes using only 1 mL of organic solvent. The ion transitions for IPMP, IBMP, MIB, and geosmin were 153 〉 121, 167 〉 125, 152 〉 95, and 165 〉 109, respectively. The linearity of this method for analyzing MIB ranged from 4 to 200ng·L^-1, and from 0.8 to 200ng·L^-1 for the other analytes. Method recoveries ranged from 97% to 111% and percent relative standard deviations ranged from 3% to 9%, indicating that the method is accurate, precise, and reliable.展开更多
文摘The synthesis and characterization of N,N＇-bis（salicylidene） ethylenediamine, Salen said that were carried out. The behavior of this ligand has been studied in solution in solvent homogeneous and heterogeneous systems in sulphate medium. The use of pH-metric titration, GRAN and JOB＇s methods have permitted the determination of different parameters governing the behavior of Salen in solution such as the acidity constant, the stability constant, the nature of the interaction solvent-solute, the solvation number, the stoichiometry of extracted complex etc.. Then the extraction of the Salen was finally undertaken to words the copper （II） sulfate medium. The pH of complexation, extraction time, the number of protons exchanged and the number of ligands have been finally determined.
基金the National Natural Science Foundation of China(Nos.20375035,20527005,20775070)by Zhejiang Provincial Natural Science Foundation of China(Nos.Z404105,Y507252).
文摘In this work, a new microextraction method termed ionic liquid based dispersive liquid-liquid microextraction （IL-DLLME） was demonstrated for the extraction of 2-methylaniline, 4-chloroaniline, 1-naphthylamine and 4-aminobiphenyl in aqueous matrices. After extraction the ionic liquid （IL） phase was injected directly into the high performance liquid chromatography （HPLC） system for determination. Some parameters that might affect the extraction efficiency were optimized. Under the optimum conditions, good linear relationship, sensitivity and reproducibility were obtained. The limits of detection （LOD, S/N = 3） for the four analytes were in the range of 0.45-2.6 μg L^-1. The relative standard deviations （R.S.D., n = 6） were in the range of 6.2-9.8%. This method was applied for the analysis of the real water samples. The recoveries ranged from 93.4 to 106.4%. The main advantages of the method are high speed, high recovery, good repeatability and volatile organic solvent-free.
基金supported both by the Natural Science Foundations of Hebei(No.B2008000210)the Scientific Research Foundation of Agricultural University of Hebei.
文摘A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.
基金Item Sponsored by National Natural Science Foundation of China (50805109)Fundamental Research Funds for Central Universities of China (2011-1a-023)
文摘Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2 and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.
文摘The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baffles in a mechanically agitated vessel is to ensure even distribution,reduce settler turbulence,promote the stability of power drawn by the impeller and to prevent swirling and vortexing of liquid,thus,greatly improving the mixing of liquid.The insertion of the appropriate number of baffles clearly improves the extent of liquid mixing.However,excessive baffling would interrupt liquid mixing and lengthen the mixing time.Computational fluid dynamics(CFD) provides a tool for determining detailed information on fluid flow(hydrodynamics) which is necessary for modeling subprocesses in mixer settler.A total of 54 final CFD runs were carried out representing different combinations of variables like number of baffles,density and impeller speed.CFD data shows that amount of separation increases with increasing baffles number and decreasing impeller speed.
基金National Iranian Oil Refining & Distribution Company(NIORDC) and Research & Development (R&D) center of this company for their financial support during the completion of this work
文摘The extractive desulfurization of a model gaso- line containing several alkyl thiols and aromatic thiophenic compounds was investigated using two imidazolium-based ionic liquids （ILs）, 1-butyl-3-methylimidazolium tetrachloroaluminate, and 1-octyl-3-methylimidazolium te- trafluoroborate, as extractants. A fractional factorial design of experiments was employed to evaluate the effects and possible interactions of several process variables. Analysis of variance tests indicated that the number of extraction steps and the IL/gasoline volume ratio were of statistically highly significant, but none of the interactions were significant. The results showed that the desulfurization efficiency of the model gasoline by the ILs could reach 95.2 % under the optimal conditions. The optimized conditions were applied to study the extraction of thiophenic compounds in model gasoline and several real gasoline samples; the following order was observed in their separation： benzothio- phenc 〉 thiophcne 〉 3-methylthiophene 〉 2-methylthiophene, with 96.1% removal efficiency for benzothiophene. The IL extraction was successfully applied as a complementary process to the adsorptive desulfurization with acti- vated Raney nickel and acetonitrile solvent. The results indicated that the adsorptive process combined with IL extraction could provide high efficiency and selectivity, which can be regarded as a promising energy efficient desulfurization strategy for production of low-sulfur gasoline.
基金supported by the Science and Technology Project of Chinese Traditional Medicine of Gansu,China(No.GZK-2011-72)Agricultural Biotechnology Research and Development Project of Gansu Province,China(No.GNSW-2013-14)
文摘OBJECTIVE： The stable quality of Chinese herbal medicines is a critical factor for their reliable clinical efficiency. An improved liquid-liquid extraction procedure and a liquid chromatographic method were developed to simultaneously analyze five anthraquinones （aloe-emodin, rhein, emodin, chrysophanol and physcion） in a Chinese traditional hospital preparation, Fuyankang mixture, in order to quantitatively control its quality in a more effective way. METHODS： A more economical and repeatable extraction procedure based on conventional liquid-liquid extraction technique was developed and used to extract five marker components in Fuyankang mixture. These anthraquinones were separated in less than 20 min on a C18 column with methanol and 0.1% phosphoric acid （88：12, v/v） as mobile phase. The method was validated for specificity, precision, spiked recovery and stability. RESULTS： Compared to conventional liquid-liquid extraction, the improved liquid-liquid extraction was found to be more effective for simultaneous extraction of anthraquinones from an aqueous Chinese herbal preparation, especially for hydrophobic compounds. The improved extraction method was successfully applied to determine the content of five marker components in Fuyankang mixture by the means of reverse phase high-performance liquid chromatography. CONCLUSION： The improved extraction procedure may be suitable for routine quality control of Fuyankanq mixture and other traditional preparations at city-level hospitals in China.
基金This work was supported by the National Natural Science Foundation of China(Nos.51774264,51574216,51974288 and 51374194)the Natural Science Foundation of Liaoning Province of China(No.2019-MS-332).
文摘The immiscible Cu-Fe alloy was characterized by a metastable miscibility gap.With the addition element Zr,the miscibility gap can be extended into the Cu-Fe-Zr ternary system.The effect of the atomic ratio of Cu to Fe and Zr content on the behavior of liquid-liquid phase separation was studied.The results show that liquid-liquid phase separation into Cu-rich and Fe-rich liquids took place in the as-quenched Cu-Fe-Zr alloy.A glassy structure with nanoscale phase separation was obtained in the as-quenched(Cu0.5Fe0.5)40Zr60 alloy sample,exhibiting a homogeneous distribution of glassy Cu-rich nanoparticles in glassy Fe-rich matrix.The microstructural evolution and the competitive mechanism of phase formation in the rapidly solidified Cu-Fe-Zr system were discussed in detail.Moreover,the electrical property of the as-quenched Cu-Fe-Zr alloy samples was examined.It displays an abnormal change of electrical resistivity upon temperature in the nanoscale-phase-separation metallic glass.The crystallization behavior of such metallic glass has been discussed.
基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(20060286034)
文摘A new technique for ice slurry production was explored. Multiple small water-drops were formed in another immiscible chilled liquid by a single-nozzled atomizer and frozen in the fluidized bed by direct contact heat transfer. Experiments were conducted to investigate the dynamic behaviors of the ice crystal making system. The results demonstrate that the ice crystals could be produced continuously and stably in the vertical bed with the circulating coolant of initial temperature below -5℃. The size distribution of the ice crystals appears non-uniform, but is more similar and more uniform at lower oil flow rate. The mean ice crystal size rests seriously with the jet velocity and the oil flow rate. It decreases with decreasing the oil flow rate, and reaches the maximum at an intermediate jet velocity at about 16.5 m.s y. The ice crystal size is also closely related to the phenomenon of drop-coalescing, which can be alleviated considerably by reducing the flow rate or lowering the temperature of the carrier oil. However, optimization of liquid-liquid atomization is a more effective approach to produce fine ice crystals of desired size.
基金supported by the National Natural Science Foundation of China under grant No.50805109the Fundamental Research Funds for the Central Universities under grant No.2011-1a-023
文摘Liners in wet ball mill for mineral processing industry must bear abrasive wear and corrosive wear, and consequently, the service life of the liner made from traditional materials, such as Hadfield steel and alloyed steels, is typically less than ten months. Bimetal liner, made from high Cr white cast iron and carbon steel, has been successfully developed by using liquid-liquid composite lost foam casting process. The microstructure and interface of the composite were analyzed using optical microscope, SEM, EDX and XRD. Micrographs indicate that the boundary of bimetal combination regions is staggered like dogtooth, two liquid metals are not mixed, and the interface presents excellent metallurgical bonding state. After heat treatment, the composite liner specimens have shown excellent properties, including hardness 〉 61 HRC, fracture toughness ak 〉16.5 J.cm2 and bending strength 〉1,600 MPa. Wear comparison was made between the bimetal composite liner and alloyed steel liner in an industrial hematite ball mill of WISCO, and the results of eight-month test in wet grinding environment have proved that the service life of the bimetal composite liner is three times as long as that of the alloyed steel liner.
文摘The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Vali-dations of analytical methods for MT residue in food and the results obtained have become indispensable. The high perfor-mance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy)at the 1, 5 and 10mg kg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation(RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10%for muscle tissue. The limit of detection was 0.05 mg kg-1.
基金financially supported by the National Foundation (grant No:51371090)the Science and Technology Support Program of the 12th Five-year Plan (grant No:2011BAD20B03010401)+1 种基金the National Natural Science Foundation of China (grant No:51203061)the College Student Science and Technology Innovation of Hei Longjiang Province (grant No:2012sj001)
文摘Crusher hammers for the mineral processing industry must meet the demands of both high wear resistance at the hammer head and high impact toughness at the hammer handle. The crusher hammers made of Hadfield steel have typical y low service life of less than 40 hours. To solve the problem, a kind of bimetal crusher hammers made of high chromium cast iron （HCCI） and low al oy steel （LAS） has been successful y developed by using liquid-liquid composite casting. The microstructure and composite interface bonding was analyzed using optical microscope, SEM, EDX and XRD. Micrographs indicate that the composite interface is metal urgical y bonded with a zigzag shape across the boundary and without unbound region or void. After heat treatment, the composite hammers have shown excellent properties. The hardness of HCCI is at least 63 HRC and its αk is greater than 3.5 J？cm-2; the hardness of LAS is greater than 35 HRC and its αk is no less than 80 J？cm-2. Diffusion of elements takes place at the interface and forms a transition region. The micro hardness increases from LAS to the interface and then to HCCI. Wear comparison was made separately between the bimetal composite hammer and a Hadfield steel hammer in two quarries of Jilin province and Liaoning province. The results showed that the liquid-liquid bimetal composite hammers did not have the fal ing off of hammer head or impact fracture phenomenon, and their service life was 3.75 times as long as that of the Hadfield steel hammers.
基金supported by the Natural Science Foundation of Hebei(No.B2010000657)
文摘A novel,simple,rapid,efficient and environment-friendly method for the determination of trace copper in cereal samples was developed by using dispersive liquid-liquid microextraction based on solidification of floating organic drop（DLLME-SFO） followed by flame atomic absorption spectrometry.In the DLLME-SFO,copper was complexed with 8-hydroxy quinoline and extracted into a small volume of 1-dodecanol,which is of low density,low toxicity and proper melting point near room temperature. The experimental parameters affecting the extraction efficiency were investigated and optimized.Under the optimum conditions, the calibration graph exhibited linearity over the range of 0.5—500 ng/mL with the correlation coefficient（r） of 0.9996.The enrichment factor was 122 and the limit of detection was 0.1 ng/mL.The method was applied to the determination of copper in the complex matrix samples such as rice and millet with the recoveries for the spiked samples at 5.0 and 10.0 u,g/g falling in the range of 92.0-98.0%and the relative standard deviation of 3.9-5.7%.
基金supported by the National Natural Science Foundation of China(81830004,31970755,and 31970173)the Local Grant(608285568031)。
文摘A key to tackling the coronavirus disease 2019(COVID-19)pandemic is to understand how severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)manages to outsmart host antiviral defense mechanisms.Stress granules(SGs),which are assembled during viral infection and function to sequester host and viral m RNAs and proteins,are part of the antiviral responses.Here,we show that the SARS-Co V-2 nucleocapsid(N)protein,an RNA binding protein essential for viral production,interacted with RasGTPase-activating protein SH3-domain-binding protein(G3 BP)and disrupted SG assembly,both of which require intrinsically disordered region1(IDR1)in N protein.The N protein partitioned into SGs through liquid-liquid phase separation with G3 BP,and blocked the interaction of G3 BP1 with other SG-related proteins.Moreover,the N protein domains important for phase separation with G3 BP and SG disassembly were required for SARS-Co V-2 viral production.We propose that N protein-mediated SG disassembly is crucial for SARS-Co V-2 production.
基金supported by the National Natural Science Foundation of China(No.11572346)。
文摘Primary breakup in a liquid-liquid pintle injector element at different radial jet velocities is investigated to elucidate the impingement morphology,the formation of primary breakup spray half cone angle,the pressure distribution,the liquid diameter distribution,and the liquid velocity distribution.With a sufficient mesh resolution,the liquid morphology can be captured in a physically sound way.A mushroom tip is triggered by a larger radial jet velocity and breakup happens at the tip edge first.Different kinds of ligament breakup patterns due to aerodynamic force and surface tension are captured on the axial sheet.A high pressure core is spotted at the impinging point region.A larger radial jet velocity can feed more disturbances into the impinging point and the axial sheet,generate stronger vortices to promote the breakup process at a longer distance,and form a larger spray half cone angle.Because of the re-collision phenomenon the axial sheet diameter does not decrease monotonically.The inner rim on the axial sheet shows a larger diameter magnitude and a lower velocity magnitude due to surface tension.This paper is expected to provide a reference for the optimum design of a liquid-liquid pintle injector.
文摘A rapid and sensitive liquid chromatography-tandem mass spectrometric（LC-MS/MS） assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma.Furosemide was used as an internal standard.Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether.The reconstituted samples were chromatographed on a Zorbax SB-C;8 column by using a mixture of 5 mM ammonium acetate buffer and acetonitrile（20:80,v/v） as the mobile phase at a flow rate of 0.8 mL/min.The calibration curve obtained was linear（r≥0.99） over the concentration range of 0.50-600.29 ng/mL for pravastatin and 20.07-2012.00 ng/mL for aspirin.Method validation was performed as per FDA guidelines and the results met the acceptance criteria.A run time of 2.0 min for each sample made it possible to analyze more than 400 human plasma samples per day.The proposed method was found to be applicable to clinical studies.
基金This study was supported by the National High-Tech Research and Development(863)Program of China(Grant No.2002AA601130)the Key Technologies Research and Development Program(No.2003BA808A17)of China.
文摘Two sample preparation methods were introduced and compared in this paper to establish a simple,quick and exact analysis of geosmin and 2-methylisoborneol.LC-18 column was employed in solid phase extraction(SPE),1.0 mL of hexane was adopted in liquid-liquid extraction(LLE),and the extracts were analyzed by gas chromatograph mass spectrum(GCMS)in selected ion mode.Mean recoveries of SPE were low for 2-methylisoborneol(2-MIB)and geosmin(GSM)with values below 50%.For LLE,the recoveries were satisfyingly above 50%for 2-MIB and 80%for GSM.Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB.A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer,there was a serious odor problem induced by a high concentration of 2-MIB.The highest concentration of 152.82 ng/L appeared in July in raw water,while GSM flocculation was minimal with concentrations below odor threshold.
基金Funded by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (ROCS, SEM [2005] No. 383)
文摘A novel process for separation of red （Y2O3： Eu^3＋）, blue （Sr, Ca, Ba）10（PO4）6Cl2： Eu^2＋ and green （LaPO4： Tb^3＋, Ce^3＋） fine tricolor phosphor powders was established. First, the green phosphor was extracted and separated from three phosphor mixtures in heptane/DMF（N, N-Dimethylformamide） system using stearylamine or laurylamine （DDA） as the cationic surfactant. Then, after being treated with 99.5% ethanol, the blue and red phosphors could be separated in Heptane/DMF system in presence of 1-octanesulfonic acid sodium salt as the anionic surfactant. Satisfactory separation results have been achieved through two steps extractions with their artificial mixtures. The grades and recovery of separated products reached respectively as follows： red product was 95.3% and 90.9%, blue product was 90.0% and 95.2%, and green product was 92.2% and 91.8%.
文摘A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavor/odor compounds, included geosmin, 2- methylisobomeol （MIB）, 2-isobutyl-3-methyoxypyrazine （IBMP）, and 2-isopropyl-3-methoxypyrazine （IPMP）. Using this method, a single sample can be extracted within minutes using only 1 mL of organic solvent. The ion transitions for IPMP, IBMP, MIB, and geosmin were 153 〉 121, 167 〉 125, 152 〉 95, and 165 〉 109, respectively. The linearity of this method for analyzing MIB ranged from 4 to 200ng·L^-1, and from 0.8 to 200ng·L^-1 for the other analytes. Method recoveries ranged from 97% to 111% and percent relative standard deviations ranged from 3% to 9%, indicating that the method is accurate, precise, and reliable.
