[Objective] The paper was to study the algicidal effect of water-soluble extracts of Chinese chive under different environmental conditions, so as to provide reference for further study and development of new algicida...[Objective] The paper was to study the algicidal effect of water-soluble extracts of Chinese chive under different environmental conditions, so as to provide reference for further study and development of new algicidal substances. [Method] The effects of water-soluble extracts of Chinese chive on the growth of Microcystis aeruginosa under different pH, light and aeration conditions were compared and studied. [Result] The growth inhibition rate of water-soluble extracts of Chinese chive on M. aeruginosa was greater than 90% under different pH conditions. With the growth of M. aeruginosa, the culture liquid with different initial pH was finally tended to 9-9.5. The growth inhibition rate of water-soluble extracts of Chinese chive on algae cell increased with the prolongation of culture time within the light intensity range of 1 000-4 000 lx. The inhibition effect of water-soluble extracts of Chinese chive on M. aeruginosa under low light intensity（1 000 lx）was better than that under high light intensity, the best light intensity for growth was not conducive to the exertion of allelopathic effect. Meanwhile, aeration condition was more conducive to the inhibition effect of water-soluble extracts of Chinese chive on the growth of M. aeruginosa. [Conclusion] pH, light and aeration conditions all affected the inhibition effect of water-soluble extracts of Chinese chive treated by high temperature on M. aeruginosa. Understanding the effect of these environmental factors on algicidal effect of allelochemicals could provide reference for further study and development of new algicidal substances.展开更多
Water-soluble polysaccharide was isolated from grapefruit with the method of water-dissolving and ethanol-precipitating. By single factor test and orthogonal experimental method, the extraction conditions of the water...Water-soluble polysaccharide was isolated from grapefruit with the method of water-dissolving and ethanol-precipitating. By single factor test and orthogonal experimental method, the extraction conditions of the water-soluble polysaccharide were investigated, which contained liquid-solid ratio, temperature, time and pH. The results showed that pH was the most important factor of polysaccharide extraction, followed by temperature. The optimized extraction technology conditions were obtained. The liquid-solid ratio was 1:40, temperature was 90?C, time was 2.0 h, and pH was 2. The highest extraction rate of crude polysaccharide was 8.30%.展开更多
Poor palatability is a limiting factor for replacing fishmeal with other protein sources in aquaculture. The water-soluble molecules with low molecular weights are the major determinants of the palatability of diets. ...Poor palatability is a limiting factor for replacing fishmeal with other protein sources in aquaculture. The water-soluble molecules with low molecular weights are the major determinants of the palatability of diets. The present study was conducted to investigate the palatability of water-soluble extracts from single protein source(single extract pellets) and the mixture of these extracts with different proportions(blended extract pellets) in juvenile turbot(Scophthalmus maximus). Then according to the palatability of blended extract pellets, an optimal mixture proportion was selected, and a new protein source made from raw protein materials with the selected proportion was formulated to replace fishmeal. Summarily, the palatability of single extract pellets for turbot was descendent from fishmeal to pet-food grade poultry by-product meal, wheat gluten meal, soybean meal, peanut meal, meat and bone meal, and corn gluten meal. Subsequently, according to the palatability of single extract pellets, 52 kinds of blended extract pellets were designed to test their palatability. The results showed that the pellets presented remarkably different palatability, and the optimal one was diet 52(wheat gluten meal: pet-food grade poultry by-product meal: meat and bone meal: corn gluten meal = 1:6:1:2). The highest ingestion ratio(the number of pellets ingested/the number of pellets fed) was 0.73 ± 0.03, which was observed in Diet 52. Then five isonitrogenous(52% crude protein) and isocaloric(20 k J g^(-1) gross energy) diets were formulated by replacing 0(control), 35%, 50%, 65% and 80% of fishmeal with No.52 blending proportion. After a 10-weeks feeding trial, a consistent feed intake was found among all replacement treatments. Replacement level of fishmeal up to 35% did not significantly influence final body weight, specific growth rate, feed efficiency ratio, and protein efficiency ratio of turbot. Therefore, the water-soluble extracts of protein sources play an important role in improving the palatability of non-fishmeal protein sources in aquafeed.展开更多
BACKGROUND This case-control study compared the short-term clinical efficacy of natural orifice specimen extraction surgery(NOSES) using a prolapsing technique and the conventional laparoscopic-assisted approach for l...BACKGROUND This case-control study compared the short-term clinical efficacy of natural orifice specimen extraction surgery(NOSES) using a prolapsing technique and the conventional laparoscopic-assisted approach for low rectal cancer.AIM To further explore the application value of the transanal placement of the anvil and to evaluate the short-term efficacy of NOSES for resecting specimens of low rectal cancer, as well as to provide a theoretical basis for its extensive clinical application.METHODS From June 2015 to June 2018, 108 consecutive laparoscopic-assisted low rectal cancer resections were performed at our center. Among them, 26 specimens were resected transanally using a prolapsing technique(NOSES), and 82 specimens were resected through a conventional abdominal wall small incision(LAP). A propensity score matching method was used to select 26 pairs of matched patients, and their perioperative data were analyzed.RESULTS The baseline data were comparable between the two matched groups. All 52 patients underwent the surgery successfully. The operative time, blood loss,number of harvested lymph nodes, postoperative complication rate,circumferential margin involvement, postoperative follow-up data, and postoperative anal function were not statistically significant. The NOSES group had shorter time to gastrointestinal function recovery(2.6 ± 1.0 d vs 3.4 ± 0.9 d, P= 0.006), shorter postoperative hospital stay(7.1 ± 1.7 d vs 8.3 ± 1.1 d, P = 0.003),lower pain score(day 1: 2.7 ± 1.8 vs 4.6 ± 1.9, day 3: 2.0 ± 1.1 vs 4.1 ± 1.2, day 5: 1.7± 0.9 vs 3.3 ± 1.0, P < 0.001), a lower rate of additional analgesic use(11.5% vs61.5%, P = 0.001), and a higher satisfaction rate in terms of the aesthetic appearance of the abdominal wall after surgery(100% vs 23.1%, P < 0.001).CONCLUSION NOSES for low rectal cancer can achieve satisfactory short-term efficacy and has advantages in reducing postoperative pain, shortening the length of postoperative hospital stay, and improving patients' satisfaction in terms of a more aesthetic appearance of the abdominal wall.展开更多
Micro-Doppler feature extraction of unmanned aerial vehicles(UAVs)is important for their identification and classification.Noise and the motion state of the UAV are the main factors that may affect feature extraction ...Micro-Doppler feature extraction of unmanned aerial vehicles(UAVs)is important for their identification and classification.Noise and the motion state of the UAV are the main factors that may affect feature extraction and estimation precision of the micro-motion parameters.The spectrum of UAV echoes is reconstructed to strengthen the micro-motion feature and reduce the influence of the noise on the condition of low signal to noise ratio(SNR).Then considering the rotor rate variance of UAV in the complex motion state,the cepstrum method is improved to extract the rotation rate of the UAV,and the blade length can be intensively estimated.The experiment results for the simulation data and measured data show that the reconstruction of the spectrum for the UAV echoes is helpful and the relative mean square root error of the rotating speed and blade length estimated by the proposed method can be improved.However,the computation complexity is higher and the heavier computation burden is required.展开更多
Aimed at the low mining efficiency in deep multi-seams because of high crustalstress,high gas content,low permeability,the compound 'three soft' roof and the trouble-somesafety situation encountered in deep le...Aimed at the low mining efficiency in deep multi-seams because of high crustalstress,high gas content,low permeability,the compound 'three soft' roof and the trouble-somesafety situation encountered in deep level coal exploitation,proposed a new idea ofgob-side retaining without a coal-pillar and Y-style ventilation in the first-mined key pressure-relieved coal seam and a new method of coal mining and gas extraction.The followingwere discovered:the dynamic evolution law of the crannies in the roof is influenced bymining,the formative rule of 'the vertical cranny-abundant area' along the gob-side,thedistribution of air pressure field in the gob,and the flowing rule of pressure-relieved gas ina Y-style ventilation system.The study also established a theoretic basis for a new miningmethod of coal mining and gas extraction which is used to extract the pressure-relievedgas by roadway retaining boreholes instead of roadway boreholes.Studied and resolvedmany difficult key problems,such as,fast roadway retaining at the gob-side without a coalpillar,Y-style ventilation and extraction of pressure-relieved gas by roadway retainingboreholes,and so on.The study innovated and integrated a whole set of technical systemsfor coal and pressure relief gas extraction.The method of the pressure-relieved gasextraction by roadway retaining had been successfully applied in 6 typical working faces inthe Huainan and Huaibei mining areas.The research can provide a scientific and reliabletechnical support and a demonstration for coal mining and gas extraction in gaseous deepmulti-seams with low permeability.展开更多
The low temperature molten salt method was used to extract potassium from K-feldspar ore, and some related factors including mass ratio between NaNO_3, NaOH, H_2O and K-feldspar ore, particle size of K-feldspar ore,re...The low temperature molten salt method was used to extract potassium from K-feldspar ore, and some related factors including mass ratio between NaNO_3, NaOH, H_2O and K-feldspar ore, particle size of K-feldspar ore,reaction temperature and time were investigated, respectively. In addition, the optimum condition for this method was determined by a series of condition experiments. What was more, the K-feldspar ore and the leach residue after reaction based on the above optimum condition were analyzed by XRD, SEM and EDS,separately. The results of which indicated that the mechanism of extraction of potassium for this method was according to the ion exchange reaction between sodium ion and potassium ion, and the extraction ratio of potassium had an obvious improvement than that of traditional methods, which could reach up to 96.25%.Therefore, this method can be a feasible solution to extract potassium from K-feldspar ore for its low energy consumption and high efficiency.展开更多
The high-value utilization of low-rank coal would allow for expanding energy sources,improving energy efficiencies,and alleviating environmental issues.In order to use low-rank coal effectively,the hypercoals(HPCs)wer...The high-value utilization of low-rank coal would allow for expanding energy sources,improving energy efficiencies,and alleviating environmental issues.In order to use low-rank coal effectively,the hypercoals(HPCs)were co-extracted from two types of low-rank coal and biomass via N-methyl-2-purrolidinone(NMP)under mild conditions.The structures of the HPCs and residues were characterized by proximate and ultimate analysis,Raman spectra,and Fourier transform infrared(FT-IR)spectra.The carbon structure changes within the raw coals and HPCs were discussed.The individual thermal dissolution of Xibu(XB)coal,Guandi(GD)coal,and the biomass demonstrated that the biomass provided the lowest thermal dissolution yield Y1 and the highest thermal soluble yield Y2 at 280℃,and the ash content of three HPCs decreased as the extraction temperature rose.Co-thermal extractions in NMP at various coal/biomass mass ratios were performed,demonstrating a positive synergic effect for Y2 in the whole coal/biomass mass ratios.The maximum value of Y2 was 52.25wt% for XB coal obtained with a XB coal/biomass of 50wt% biomass.The maximum value of Y2 was 50.77wt% for GD coal obtained with a GD coal/biomass of 1:4.The difference for the optimal coal/biomass mass ratios between XB and GD coals could be attributed to the different co-extraction mechanisms for this two type coals.展开更多
The recovery of zinc from low-grade zinc oxide ores with solvent extraction-electrowinning technique was investigated by using D2EHPA as extractant and 260 # kerosene as diluent. The results show that it is possible t...The recovery of zinc from low-grade zinc oxide ores with solvent extraction-electrowinning technique was investigated by using D2EHPA as extractant and 260 # kerosene as diluent. The results show that it is possible to selectively leach zinc from the ores by heap leaching. The zinc concentration of leach solution in the first leaching cycle is 32.57 g/L, and in the sixteenth cycle the zinc concentration is 8.27g/L after solvent extraction. The leaching solution is subjected to solvent extraction, scrubbing and selective stripping for enrichment of zinc and removal of impurities. The pregnant zinc sulfate solution produced from the stripping cycle is suitable for zinc electrowinning. Extra-pure zinc metal was obtained in the electrowinning test under conventional conditions.展开更多
[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning...[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning method on RNA extraction. [ Method] Roots of herba violae were respectively crushed by using liquid nitrogen grinding method and low-temperature sectioning method to extract RNA. The extraction effects of these two methods were compared based on detec- tion of RNA concentration, purity and integrity and amplification of GAPDH gene by RT-PCR. [Result] The concentration of RNA extracted by liquid nitrogen grinding method and low-temperature sectioning method was 1.21 and 3.57 p^g/~, respectively. Both RNA extracted by these two methods showed two distinct bands after agarose gel electrophoresis. The ratio of brightness of the 28S rRNA to the 18S rRNA bands was greater than 1. PCR amplification showed that the length of GAPDH gene was about 230 bp, which was consistent with the expected result. [ Conclusion ] The experimental results indicated that using low-tempera ture sectioning method to crush the roots of herba violae can meet the needs of most molecular biological experiments including gene cloning and expression analysis, which is an effective and simple method for extracting RNA from plant roots.展开更多
The low temperature coal tar(CT)is taken as the raw material,and the extraction and column chromatography are used for detailed and accurate characterization in this paper.The n-heptane soluble fraction(CT-HS)and inso...The low temperature coal tar(CT)is taken as the raw material,and the extraction and column chromatography are used for detailed and accurate characterization in this paper.The n-heptane soluble fraction(CT-HS)and insoluble fraction(CT-HI)were obtained by n-heptane Soxhlet extraction.The extraction rate of CT-HS reached 92.79%(mass),which indicated that there are few heavy compounds in it.Further,different solvents(methylbenzene,benzene,ethyl acetate,methylbenzene-ethanol)were used to elute CT-HS by chromatographic column to obtain five fractions(saturates,aromatics,heteroatoms,phenolics and resins,named CT-SA,CT-AR,CT-HE,CT-PH,CT-RE,respectively).The yields of CTSA,CT-AR,CT-HE,CT-PH,CT-RE are 42.12%,10.43%,2.19%,9.50%and 6.63%(mass),respectively.Gas chromatography-mass spectrometry analysis of eluting components show that alkanes are the main components in CT,followed by polycyclic aromatics,and the corresponding fractions are CT-SA and CT-AR,respectively.The relative content of aliphatics in CT-SA is 76.93%,and the relative content of aromatics in CT-AR is 75.05%.This separation technology effectively separates and enriches different components in CT,and the activation energy required for the pyrolysis process of a single eluting fraction is lower than that of CT,which is expected to provide an important reference for the separation,analysis and conversion of complex oil products such as coal-oil co-processing products,coal tar and other complex heavy carbon oil products.展开更多
This review summarized the valuable works on the extraction technologies using pure liquefied dimethyl ether(DME)as the organic solvent.DME is a colorless gas with a slight ether-like fragrance at room temperature and...This review summarized the valuable works on the extraction technologies using pure liquefied dimethyl ether(DME)as the organic solvent.DME is a colorless gas with a slight ether-like fragrance at room temperature and pressure.Due to some special properties,such as the strong ability for extracting organic compounds and water,high extraction rate,cheap price,low extraction temperature,and energy consumption,environmental friend-liness,safety,and good compressibility,the application of liquefied DME to the extraction process shows many advantages and has strong potential market competitiveness.On the other hand,the drawbacks of liquefied DME extraction technology were also revealed,mainly on fire hazards,solvent loss,and lack of large-scale application.Furthermore,the previous studies on the application of liquefied DME extraction technology were divided into three parts based on the extracts(water,lipid/oil,and specific ingredients)and listed one by one.The research of the liquefied DME extraction process is still in development.In the future,it is expected that this technology can be continuously improved and optimized in both lab and industrial scales,together with the extension of its application range to more various natural resources.展开更多
基金Supported by National Natural Science Foundation of China(30671240,30871588,41006097)Scientific Special Research Project of Ministry of Water Resources for Public Industry(200801028,200701031)+1 种基金Open Fund from Key Laboratory of Environmental Materials and Environmental Engineering of Jiangsu Province(K090025)Project of Yangzhou Polytechnic College of Environment and Resource(2010YZY-1)~~
文摘[Objective] The paper was to study the algicidal effect of water-soluble extracts of Chinese chive under different environmental conditions, so as to provide reference for further study and development of new algicidal substances. [Method] The effects of water-soluble extracts of Chinese chive on the growth of Microcystis aeruginosa under different pH, light and aeration conditions were compared and studied. [Result] The growth inhibition rate of water-soluble extracts of Chinese chive on M. aeruginosa was greater than 90% under different pH conditions. With the growth of M. aeruginosa, the culture liquid with different initial pH was finally tended to 9-9.5. The growth inhibition rate of water-soluble extracts of Chinese chive on algae cell increased with the prolongation of culture time within the light intensity range of 1 000-4 000 lx. The inhibition effect of water-soluble extracts of Chinese chive on M. aeruginosa under low light intensity（1 000 lx）was better than that under high light intensity, the best light intensity for growth was not conducive to the exertion of allelopathic effect. Meanwhile, aeration condition was more conducive to the inhibition effect of water-soluble extracts of Chinese chive on the growth of M. aeruginosa. [Conclusion] pH, light and aeration conditions all affected the inhibition effect of water-soluble extracts of Chinese chive treated by high temperature on M. aeruginosa. Understanding the effect of these environmental factors on algicidal effect of allelochemicals could provide reference for further study and development of new algicidal substances.
文摘Water-soluble polysaccharide was isolated from grapefruit with the method of water-dissolving and ethanol-precipitating. By single factor test and orthogonal experimental method, the extraction conditions of the water-soluble polysaccharide were investigated, which contained liquid-solid ratio, temperature, time and pH. The results showed that pH was the most important factor of polysaccharide extraction, followed by temperature. The optimized extraction technology conditions were obtained. The liquid-solid ratio was 1:40, temperature was 90?C, time was 2.0 h, and pH was 2. The highest extraction rate of crude polysaccharide was 8.30%.
基金supported by Special Fund for Agroscientific Research in the Public Interest (201303053)Provincial Natural Science Foundation of Shandong (JQ201206) to G.H
文摘Poor palatability is a limiting factor for replacing fishmeal with other protein sources in aquaculture. The water-soluble molecules with low molecular weights are the major determinants of the palatability of diets. The present study was conducted to investigate the palatability of water-soluble extracts from single protein source(single extract pellets) and the mixture of these extracts with different proportions(blended extract pellets) in juvenile turbot(Scophthalmus maximus). Then according to the palatability of blended extract pellets, an optimal mixture proportion was selected, and a new protein source made from raw protein materials with the selected proportion was formulated to replace fishmeal. Summarily, the palatability of single extract pellets for turbot was descendent from fishmeal to pet-food grade poultry by-product meal, wheat gluten meal, soybean meal, peanut meal, meat and bone meal, and corn gluten meal. Subsequently, according to the palatability of single extract pellets, 52 kinds of blended extract pellets were designed to test their palatability. The results showed that the pellets presented remarkably different palatability, and the optimal one was diet 52(wheat gluten meal: pet-food grade poultry by-product meal: meat and bone meal: corn gluten meal = 1:6:1:2). The highest ingestion ratio(the number of pellets ingested/the number of pellets fed) was 0.73 ± 0.03, which was observed in Diet 52. Then five isonitrogenous(52% crude protein) and isocaloric(20 k J g^(-1) gross energy) diets were formulated by replacing 0(control), 35%, 50%, 65% and 80% of fishmeal with No.52 blending proportion. After a 10-weeks feeding trial, a consistent feed intake was found among all replacement treatments. Replacement level of fishmeal up to 35% did not significantly influence final body weight, specific growth rate, feed efficiency ratio, and protein efficiency ratio of turbot. Therefore, the water-soluble extracts of protein sources play an important role in improving the palatability of non-fishmeal protein sources in aquafeed.
基金Supported by National Natural Science Foundation of China,No.81500430 and No.U1304802(to Lin XH)Basic and Frontier Technology Research Program of Henan Province,No.162300410101(to Hu JH)+1 种基金Wu Jieping Medical Foundation of Clinical Research Special Fund,No.320.2710.1836(to Hu JH)The Henan Science and Technology Planning Project,No.182102310544(to Lin XH)
文摘BACKGROUND This case-control study compared the short-term clinical efficacy of natural orifice specimen extraction surgery(NOSES) using a prolapsing technique and the conventional laparoscopic-assisted approach for low rectal cancer.AIM To further explore the application value of the transanal placement of the anvil and to evaluate the short-term efficacy of NOSES for resecting specimens of low rectal cancer, as well as to provide a theoretical basis for its extensive clinical application.METHODS From June 2015 to June 2018, 108 consecutive laparoscopic-assisted low rectal cancer resections were performed at our center. Among them, 26 specimens were resected transanally using a prolapsing technique(NOSES), and 82 specimens were resected through a conventional abdominal wall small incision(LAP). A propensity score matching method was used to select 26 pairs of matched patients, and their perioperative data were analyzed.RESULTS The baseline data were comparable between the two matched groups. All 52 patients underwent the surgery successfully. The operative time, blood loss,number of harvested lymph nodes, postoperative complication rate,circumferential margin involvement, postoperative follow-up data, and postoperative anal function were not statistically significant. The NOSES group had shorter time to gastrointestinal function recovery(2.6 ± 1.0 d vs 3.4 ± 0.9 d, P= 0.006), shorter postoperative hospital stay(7.1 ± 1.7 d vs 8.3 ± 1.1 d, P = 0.003),lower pain score(day 1: 2.7 ± 1.8 vs 4.6 ± 1.9, day 3: 2.0 ± 1.1 vs 4.1 ± 1.2, day 5: 1.7± 0.9 vs 3.3 ± 1.0, P < 0.001), a lower rate of additional analgesic use(11.5% vs61.5%, P = 0.001), and a higher satisfaction rate in terms of the aesthetic appearance of the abdominal wall after surgery(100% vs 23.1%, P < 0.001).CONCLUSION NOSES for low rectal cancer can achieve satisfactory short-term efficacy and has advantages in reducing postoperative pain, shortening the length of postoperative hospital stay, and improving patients' satisfaction in terms of a more aesthetic appearance of the abdominal wall.
基金supported by the National Natural Science Foundation of China(62141108)Natural Science Foundation of Tianjin(19JCQNJC01000)。
文摘Micro-Doppler feature extraction of unmanned aerial vehicles(UAVs)is important for their identification and classification.Noise and the motion state of the UAV are the main factors that may affect feature extraction and estimation precision of the micro-motion parameters.The spectrum of UAV echoes is reconstructed to strengthen the micro-motion feature and reduce the influence of the noise on the condition of low signal to noise ratio(SNR).Then considering the rotor rate variance of UAV in the complex motion state,the cepstrum method is improved to extract the rotation rate of the UAV,and the blade length can be intensively estimated.The experiment results for the simulation data and measured data show that the reconstruction of the spectrum for the UAV echoes is helpful and the relative mean square root error of the rotating speed and blade length estimated by the proposed method can be improved.However,the computation complexity is higher and the heavier computation burden is required.
文摘Aimed at the low mining efficiency in deep multi-seams because of high crustalstress,high gas content,low permeability,the compound 'three soft' roof and the trouble-somesafety situation encountered in deep level coal exploitation,proposed a new idea ofgob-side retaining without a coal-pillar and Y-style ventilation in the first-mined key pressure-relieved coal seam and a new method of coal mining and gas extraction.The followingwere discovered:the dynamic evolution law of the crannies in the roof is influenced bymining,the formative rule of 'the vertical cranny-abundant area' along the gob-side,thedistribution of air pressure field in the gob,and the flowing rule of pressure-relieved gas ina Y-style ventilation system.The study also established a theoretic basis for a new miningmethod of coal mining and gas extraction which is used to extract the pressure-relievedgas by roadway retaining boreholes instead of roadway boreholes.Studied and resolvedmany difficult key problems,such as,fast roadway retaining at the gob-side without a coalpillar,Y-style ventilation and extraction of pressure-relieved gas by roadway retainingboreholes,and so on.The study innovated and integrated a whole set of technical systemsfor coal and pressure relief gas extraction.The method of the pressure-relieved gasextraction by roadway retaining had been successfully applied in 6 typical working faces inthe Huainan and Huaibei mining areas.The research can provide a scientific and reliabletechnical support and a demonstration for coal mining and gas extraction in gaseous deepmulti-seams with low permeability.
基金Supported by the National Natural Science Foundation of China(21373252)Fundamental Research Project of Qing Hai Science&Technology Department(2016-ZJ-749)Qinghai Innovation Fund for Technology Based Firms(2014-GX-Q19)
文摘The low temperature molten salt method was used to extract potassium from K-feldspar ore, and some related factors including mass ratio between NaNO_3, NaOH, H_2O and K-feldspar ore, particle size of K-feldspar ore,reaction temperature and time were investigated, respectively. In addition, the optimum condition for this method was determined by a series of condition experiments. What was more, the K-feldspar ore and the leach residue after reaction based on the above optimum condition were analyzed by XRD, SEM and EDS,separately. The results of which indicated that the mechanism of extraction of potassium for this method was according to the ion exchange reaction between sodium ion and potassium ion, and the extraction ratio of potassium had an obvious improvement than that of traditional methods, which could reach up to 96.25%.Therefore, this method can be a feasible solution to extract potassium from K-feldspar ore for its low energy consumption and high efficiency.
基金financially supported by the National Natural Science Foundation of China (No. 51574023)
文摘The high-value utilization of low-rank coal would allow for expanding energy sources,improving energy efficiencies,and alleviating environmental issues.In order to use low-rank coal effectively,the hypercoals(HPCs)were co-extracted from two types of low-rank coal and biomass via N-methyl-2-purrolidinone(NMP)under mild conditions.The structures of the HPCs and residues were characterized by proximate and ultimate analysis,Raman spectra,and Fourier transform infrared(FT-IR)spectra.The carbon structure changes within the raw coals and HPCs were discussed.The individual thermal dissolution of Xibu(XB)coal,Guandi(GD)coal,and the biomass demonstrated that the biomass provided the lowest thermal dissolution yield Y1 and the highest thermal soluble yield Y2 at 280℃,and the ash content of three HPCs decreased as the extraction temperature rose.Co-thermal extractions in NMP at various coal/biomass mass ratios were performed,demonstrating a positive synergic effect for Y2 in the whole coal/biomass mass ratios.The maximum value of Y2 was 52.25wt% for XB coal obtained with a XB coal/biomass of 50wt% biomass.The maximum value of Y2 was 50.77wt% for GD coal obtained with a GD coal/biomass of 1:4.The difference for the optimal coal/biomass mass ratios between XB and GD coals could be attributed to the different co-extraction mechanisms for this two type coals.
文摘The recovery of zinc from low-grade zinc oxide ores with solvent extraction-electrowinning technique was investigated by using D2EHPA as extractant and 260 # kerosene as diluent. The results show that it is possible to selectively leach zinc from the ores by heap leaching. The zinc concentration of leach solution in the first leaching cycle is 32.57 g/L, and in the sixteenth cycle the zinc concentration is 8.27g/L after solvent extraction. The leaching solution is subjected to solvent extraction, scrubbing and selective stripping for enrichment of zinc and removal of impurities. The pregnant zinc sulfate solution produced from the stripping cycle is suitable for zinc electrowinning. Extra-pure zinc metal was obtained in the electrowinning test under conventional conditions.
基金Supported by National Natural Science Foundation of China(81001700)Project of Sichuan Provincial Education Department(11ZB227,11ZB124)Research Project for the Application Foundation of Sichuan Provincial Science and Technology Department(2012JY0081)
文摘[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning method on RNA extraction. [ Method] Roots of herba violae were respectively crushed by using liquid nitrogen grinding method and low-temperature sectioning method to extract RNA. The extraction effects of these two methods were compared based on detec- tion of RNA concentration, purity and integrity and amplification of GAPDH gene by RT-PCR. [Result] The concentration of RNA extracted by liquid nitrogen grinding method and low-temperature sectioning method was 1.21 and 3.57 p^g/~, respectively. Both RNA extracted by these two methods showed two distinct bands after agarose gel electrophoresis. The ratio of brightness of the 28S rRNA to the 18S rRNA bands was greater than 1. PCR amplification showed that the length of GAPDH gene was about 230 bp, which was consistent with the expected result. [ Conclusion ] The experimental results indicated that using low-tempera ture sectioning method to crush the roots of herba violae can meet the needs of most molecular biological experiments including gene cloning and expression analysis, which is an effective and simple method for extracting RNA from plant roots.
基金financed by the project supported by the National Natural Science Foundation of China(22078266,21908180,22178289,22278338)the Key Research and Development Program of Shaanxi(2020ZDLGY11-02,2021GY-136)the Special Fund for High-level Scholars of China(XJ21B10)。
文摘The low temperature coal tar(CT)is taken as the raw material,and the extraction and column chromatography are used for detailed and accurate characterization in this paper.The n-heptane soluble fraction(CT-HS)and insoluble fraction(CT-HI)were obtained by n-heptane Soxhlet extraction.The extraction rate of CT-HS reached 92.79%(mass),which indicated that there are few heavy compounds in it.Further,different solvents(methylbenzene,benzene,ethyl acetate,methylbenzene-ethanol)were used to elute CT-HS by chromatographic column to obtain five fractions(saturates,aromatics,heteroatoms,phenolics and resins,named CT-SA,CT-AR,CT-HE,CT-PH,CT-RE,respectively).The yields of CTSA,CT-AR,CT-HE,CT-PH,CT-RE are 42.12%,10.43%,2.19%,9.50%and 6.63%(mass),respectively.Gas chromatography-mass spectrometry analysis of eluting components show that alkanes are the main components in CT,followed by polycyclic aromatics,and the corresponding fractions are CT-SA and CT-AR,respectively.The relative content of aliphatics in CT-SA is 76.93%,and the relative content of aromatics in CT-AR is 75.05%.This separation technology effectively separates and enriches different components in CT,and the activation energy required for the pyrolysis process of a single eluting fraction is lower than that of CT,which is expected to provide an important reference for the separation,analysis and conversion of complex oil products such as coal-oil co-processing products,coal tar and other complex heavy carbon oil products.
文摘This review summarized the valuable works on the extraction technologies using pure liquefied dimethyl ether(DME)as the organic solvent.DME is a colorless gas with a slight ether-like fragrance at room temperature and pressure.Due to some special properties,such as the strong ability for extracting organic compounds and water,high extraction rate,cheap price,low extraction temperature,and energy consumption,environmental friend-liness,safety,and good compressibility,the application of liquefied DME to the extraction process shows many advantages and has strong potential market competitiveness.On the other hand,the drawbacks of liquefied DME extraction technology were also revealed,mainly on fire hazards,solvent loss,and lack of large-scale application.Furthermore,the previous studies on the application of liquefied DME extraction technology were divided into three parts based on the extracts(water,lipid/oil,and specific ingredients)and listed one by one.The research of the liquefied DME extraction process is still in development.In the future,it is expected that this technology can be continuously improved and optimized in both lab and industrial scales,together with the extension of its application range to more various natural resources.
