Due to severe mass transfer limitations,contaminated soils with low-permeability limit the accessibility of amendments,resulting in less effective or even ineffective remediation.Enhancing the mass transfer properties...Due to severe mass transfer limitations,contaminated soils with low-permeability limit the accessibility of amendments,resulting in less effective or even ineffective remediation.Enhancing the mass transfer properties of low-permeability soils by hydraulic fracturing is a promising technique.A quasi-three-dimensional(quasi-3D)analytical model was presented that accounted for advection-diffusion-adsorption-degradation processes in the fracture-matrix system.The model combined the injection-extraction technique to investigate the enhanced transport of amendments in low-permeability contaminated soil by hydraulic fractures.Then,the injection strategy and controllable parameter optimization were comprehensively studied by analyzing the radial transport behavior of the amendment within hydraulic fractures.The results showed that higher injection volumetric rates accelerated the formation of a uniform line source within the fractures.Although the differences in the effective ratio of the amendment among different injection modes were not significant,considering the amendment utilization rate and cost reduction,the recommended injection strategy was the combination of continuous pulsing injection and periodic injection.展开更多
The sulfur phase in high sulfur-containing bauxite was studied by an X-ray diffraction analysis and a chemistry quantitative analysis.The methods for the removal of different shaped sulfur were also discussed.The resu...The sulfur phase in high sulfur-containing bauxite was studied by an X-ray diffraction analysis and a chemistry quantitative analysis.The methods for the removal of different shaped sulfur were also discussed.The results show that sulfur phases in high sulfur-containing bauxites exist in the main form of sulfide sulfur （pyrite） or sulfate sulfur,and the main sulfur forms of bauxites from different regions are not the same.Through a combination of an X-ray diffraction analysis and a chemistry quantitative analysis,the sulfur phases of high sulfur-containing bauxite could be accurately investigated.Deciding the main sulfur form of high sulfur-containing bauxite could provide theoretical instruction for choosing methods for the removal of sulfur from bauxite,and an oxidizing-roasting process is an effective way to remove sulfide sulfur from high sulfur-containing bauxite,the content of S^2-in crude ore in the digestion liquor is above 1.7 g/L,but in the roasted ore digestion liquor,it is below 0.18 g/L.Using the sodium carbonate solution washing technology to wash bauxite can effectively remove sulfate sulfur,the content of the total sulfur in ore is lowered to below 0.2% and can meet the production requirements for the sulfur content.展开更多
Facing keen competition in telecom marketsworldwide, global mobile operators arelooking for the best solution that can notonly make full use of existing networkresources, but also introduce new technologiesfor new ser...Facing keen competition in telecom marketsworldwide, global mobile operators arelooking for the best solution that can notonly make full use of existing networkresources, but also introduce new technologiesfor new service provision.The CDMA network features great capacity,strong anti-jamming functionality, good voicequality and low power consumption of terminals,with which CDMA operators can reduce theirinvestment in equipment and cost of networkoperation and maintenance. In addition, whentransiting to 3G, the CDMA system canimplement smooth evolution from IS-95A toCDMA2000 1X and then to CDMA2000 1xEV withlow cost.展开更多
The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems (LS-1 to LS-12) were prepared using differ...The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems (LS-1 to LS-12) were prepared using different vehicles (PEG 200, PEG 400 and Tween 80) and curcumin concentrations in vehicle (40%, 50%, 60% and 70%, w/w). The carrier [microcrystalline cellulose (MCC) PH102] to coat (Aerosil<sup>®</sup>) ratio was 20 in all formulations. The systems were screened for pre-compression properties before being compressed to liquisolid tablets (LT-1 to LT-12). Post compression tests and in vitro dissolution of LTs were conducted and the results compared with those obtained for a directly compressed tablet (DCT) made of curcumin, MCC PH102 and Aerosil<sup>®</sup>. LTs exhibited higher cumulative drug release (CDR) than the DCT and the optimum formulation, LT-9 (made using Tween 80), was studied by powder XRD, DSC, SEM and FTIR. Ex-vivo permeation of curcumin from LT-9 through goat gastrointestinal mucosa was significantly (P<0.05) enhanced and its oral bioavailability was increased 18.6-fold in New Zealand rabbits. In vitro cytotoxicity (IC<sub>50</sub>) of LT-9 towards NCL 87 cancer cells was 40.2 µmol/L substantiating its anticancer efficacy. Accelerated stability studies revealed insignificant effects of temperature and humidity on LT-9. In summary, solubility enhancement of curcumin in LTs produced significant improvements in its permeation and bioavailability.展开更多
基金supported by the National Key Research and Development Program of China (Grant No.2020YFC1808104)the National Natural Science Foundation of China (Grant Nos.42227804 and 41931289).
文摘Due to severe mass transfer limitations,contaminated soils with low-permeability limit the accessibility of amendments,resulting in less effective or even ineffective remediation.Enhancing the mass transfer properties of low-permeability soils by hydraulic fracturing is a promising technique.A quasi-three-dimensional(quasi-3D)analytical model was presented that accounted for advection-diffusion-adsorption-degradation processes in the fracture-matrix system.The model combined the injection-extraction technique to investigate the enhanced transport of amendments in low-permeability contaminated soil by hydraulic fractures.Then,the injection strategy and controllable parameter optimization were comprehensively studied by analyzing the radial transport behavior of the amendment within hydraulic fractures.The results showed that higher injection volumetric rates accelerated the formation of a uniform line source within the fractures.Although the differences in the effective ratio of the amendment among different injection modes were not significant,considering the amendment utilization rate and cost reduction,the recommended injection strategy was the combination of continuous pulsing injection and periodic injection.
基金Project(20971041) supported by the National Natural Science Foundation of ChinaProject(09B032) supported by Scientific Research Fund of Hunan Provincial Education Department,China
文摘The sulfur phase in high sulfur-containing bauxite was studied by an X-ray diffraction analysis and a chemistry quantitative analysis.The methods for the removal of different shaped sulfur were also discussed.The results show that sulfur phases in high sulfur-containing bauxites exist in the main form of sulfide sulfur （pyrite） or sulfate sulfur,and the main sulfur forms of bauxites from different regions are not the same.Through a combination of an X-ray diffraction analysis and a chemistry quantitative analysis,the sulfur phases of high sulfur-containing bauxite could be accurately investigated.Deciding the main sulfur form of high sulfur-containing bauxite could provide theoretical instruction for choosing methods for the removal of sulfur from bauxite,and an oxidizing-roasting process is an effective way to remove sulfide sulfur from high sulfur-containing bauxite,the content of S^2-in crude ore in the digestion liquor is above 1.7 g/L,but in the roasted ore digestion liquor,it is below 0.18 g/L.Using the sodium carbonate solution washing technology to wash bauxite can effectively remove sulfate sulfur,the content of the total sulfur in ore is lowered to below 0.2% and can meet the production requirements for the sulfur content.
文摘Facing keen competition in telecom marketsworldwide, global mobile operators arelooking for the best solution that can notonly make full use of existing networkresources, but also introduce new technologiesfor new service provision.The CDMA network features great capacity,strong anti-jamming functionality, good voicequality and low power consumption of terminals,with which CDMA operators can reduce theirinvestment in equipment and cost of networkoperation and maintenance. In addition, whentransiting to 3G, the CDMA system canimplement smooth evolution from IS-95A toCDMA2000 1X and then to CDMA2000 1xEV withlow cost.
文摘The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems (LS-1 to LS-12) were prepared using different vehicles (PEG 200, PEG 400 and Tween 80) and curcumin concentrations in vehicle (40%, 50%, 60% and 70%, w/w). The carrier [microcrystalline cellulose (MCC) PH102] to coat (Aerosil<sup>®</sup>) ratio was 20 in all formulations. The systems were screened for pre-compression properties before being compressed to liquisolid tablets (LT-1 to LT-12). Post compression tests and in vitro dissolution of LTs were conducted and the results compared with those obtained for a directly compressed tablet (DCT) made of curcumin, MCC PH102 and Aerosil<sup>®</sup>. LTs exhibited higher cumulative drug release (CDR) than the DCT and the optimum formulation, LT-9 (made using Tween 80), was studied by powder XRD, DSC, SEM and FTIR. Ex-vivo permeation of curcumin from LT-9 through goat gastrointestinal mucosa was significantly (P<0.05) enhanced and its oral bioavailability was increased 18.6-fold in New Zealand rabbits. In vitro cytotoxicity (IC<sub>50</sub>) of LT-9 towards NCL 87 cancer cells was 40.2 µmol/L substantiating its anticancer efficacy. Accelerated stability studies revealed insignificant effects of temperature and humidity on LT-9. In summary, solubility enhancement of curcumin in LTs produced significant improvements in its permeation and bioavailability.
