Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon d...Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon dioxide with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in super-critical CO2 with cosolvent acetone was measured using a dynamic apparatus at pressures between 12 and 32 MPa,temperatures at 313, 323 and 333 K and cosolvent concentration at 1.5, 3.0, 4.5 and 6.0% (by mole). The effect of pre-expansion pressure, extraction temperature, spraying distance, nozzle size and concentration of cosolvent on the precipitated particles was investigated. The results show that the mean particle size of griseofulvin precipitated by RESS was less than 1.2μm. An increase in pre-expansion pressure, extraction temperature, spraying distance and concentration of cosolvent resulted in a decrease in particle size under the operating condition studied. With the decrease of nozzle diameter the particle size reduces. The crystallinity and melting point of the original material and the processed particle by RESS were tested by X-ray diffraction (XRD) and differential scanning calorimetry (DSC).No evident modification in the crystal habit was found under the experimental conditions tested. The morphology of particles precipitated was analyzed bY scanning electron microscopy (SEM).展开更多
The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an opt...The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an optimum porosity of 0.32 to get a higher efficiency and lower pressure drop during filtration.According to the results of simulation and experiment,it is evident that lower inlet velocity can maintain lower pressure drop and obtain higher collection efficiency and inlet concentration also has a crucial influence on the collection efficiency.The collection efficiency of equipment increases significantly with the increase of inlet concentration when the inlet concentration is less than 6.3 g/m3,but it gradually tends to be stable in the range of 97.3%-99.7%when the inlet concentration is over this concentration.展开更多
Papaya pulp is very perishable and has a short shelf life. Manually sliced papayas were treated with 0%, 0.25%, 0.5%, and 1% chitosan (non-micronized and micronized) aqueous solutions;placed into plastic trays, and ov...Papaya pulp is very perishable and has a short shelf life. Manually sliced papayas were treated with 0%, 0.25%, 0.5%, and 1% chitosan (non-micronized and micronized) aqueous solutions;placed into plastic trays, and over-wrapped with PVDC film and then stored at 4°C. Color, soluble solid content, water loss, and total plate count of samples were evaluated. Chitosan coating had the ability to maintain the lightness of the sliced papayas. The a* values of the micronized chitosan-coated sliced papayas were significantly lower than those of the-coated. The sliced papayas that had been treated with 1% MC had a higher total soluble solid content and lower b* value after four days of storage. Also, the chitosan coating on the sliced papaya effectively retarded water loss and inhibited the growth of microorganisms. The results reveal that applying a chitosan coating effectively maintained the quality attributes and prolonged the shelf life of the sliced papayas.展开更多
Life cycle assessment is applied to assess the ultra-clean micronized coal oil water slurry (UCMCOWS) with SimaPro and the environmental impact of UCMCOWS on its whole life cycle is also analyzed. The result shows tha...Life cycle assessment is applied to assess the ultra-clean micronized coal oil water slurry (UCMCOWS) with SimaPro and the environmental impact of UCMCOWS on its whole life cycle is also analyzed. The result shows that the consumption of energy and products are increasing along with the deepening of UCMCOWS processing, UCMCOWS making and combustion are the two periods which have a bigger impact on eco-system and human health. As a new substitute of fuel, UCMCOWS merits to be utilized more efficiently and reasonably.展开更多
The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al_2O_(3p)/6061Al and the weldability of the material were studied. Experimental results indicated that because of the h...The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al_2O_(3p)/6061Al and the weldability of the material were studied. Experimental results indicated that because of the huge specific surface area of the reinforcement, the interfacial reaction between the matrix and the reinforcement was re- strained intenslvely at elevated temperature and pulsed laser beam. The main factor affecting the weldability of the com- posite was the reinforcement segregation in the weld resulting from the push of the liquid/solid interface during the soli- dification of the molten pool. The laser pulse frequency directly affected the reinforcement segregation and the reinfor- cement distribution in the weld, so that the weldability of the composite could be improved by increasing the laser pulse frequency. On the basis of this, a satisfactory welded joint of sub-micron paniculate-reinforced aluminum matrix com- posite Al_2O_(3p)/6061Al was obtained by using appopriate welding parameters.展开更多
Marble that exploited for micronized calcite production in Nigde area (South Central Turkey) occur in the Upper Cretaceous Gümü ler, A gedi i, and Kaleboynu Formations of the Nigde Massif. Although there are...Marble that exploited for micronized calcite production in Nigde area (South Central Turkey) occur in the Upper Cretaceous Gümü ler, A gedi i, and Kaleboynu Formations of the Nigde Massif. Although there are a few marble producing quarries in the area, it is long been known that the marbles of this area are generally highly fractured and don’t yield large blocks or suitable slabs meeting the industrial demands. Thus, most of the production is currently carried out mainly as building stone, crushed stone and micronized calcite. Due mainly to high demand, micronized calcite has been becoming very significant export product to the state’s economy. Because the Nigde marbles are coarse grained with high CaCO3 content, high purity and whiteness, they are considered to be the highest quality micronized calcite quarries in the country. Consequently, the area drew many national and international investors resulting in significant increase in the number and extent of micronized calcite plants in the area. In early 1980’s, the city of Nigde had only one or two plants, it is now well over 5 including foreign investors and joint ventures. Annual production is also considerably increased from 20,000-30,000 tones to almost half a million tones and it is still in increasing trend.展开更多
The Experiments, methods and results of obtaining micron beam in the Microbeam Facility of the Institute of Plasma Physics were discussed in this paper. The H+2 beam was accelerated by the Van de GraafF electrostatic ...The Experiments, methods and results of obtaining micron beam in the Microbeam Facility of the Institute of Plasma Physics were discussed in this paper. The H+2 beam was accelerated by the Van de GraafF electrostatic accelerator, and the collimator at the end of the beam line is a 60 μm thick stainless steel chip. And as a result, particle tracks on the solid track probes (CR39 film) etched in the solution of NaOH showed that the beam can go through the collimator with a small aperure (2000, 300, 55, 30, or 10 μm) and 3.5 μm thick vacuum film (Mylar). Besides the CR39 method, the beam was measured by an energy spectrum detector after the 10 μm diameter aperture and the 3.5 μm thick vacuum film too.展开更多
The antioxidant activity of chitosan before micronization (BMC, average particle size of 1850 ± 26.3 μm) and after micronization (AMC, average particle size of 1.37 ± 0.2 μm) in grape juice was studied. An...The antioxidant activity of chitosan before micronization (BMC, average particle size of 1850 ± 26.3 μm) and after micronization (AMC, average particle size of 1.37 ± 0.2 μm) in grape juice was studied. Antioxidant activity was determined, including that of DPPH radicals, hydrogen peroxide and superoxide anion radicals, as well as ABTS radicals of BMC or AMC in grape juice. AMC exhibits stronger scavenging activity toward DPPH radicals, superoxide anion radicals and hydrogen peroxide than BMC. At a concentration of 1.0 mg/mL, AMC in grape juice exhibited 90.0%, 97.3% and 88.7% scavenging activities toward DPPH radicals, hydrogen peroxide and superoxide anion radicals, respectively. The TEAC (Trolox Equivalent Antioxidant Capacity) values of AMC (3.94 ± 0.19) greatly exceeded those of BMC (2.21 ± 0.10) in grape juice. The in vitro results in this investigation suggest the possibility that AMC can increase the antioxidant activity in grape juice. However, comprehensive studies must be performed to ascertain the in vivo safety of AMC in experimental animal models.展开更多
Co3O4 powder has a wide range of applications in the fields of catalysts, magnetic materials and electrochemistry. Especially after the 1990s, the demand for lithium ion battery industry has grown tremendously. The tr...Co3O4 powder has a wide range of applications in the fields of catalysts, magnetic materials and electrochemistry. Especially after the 1990s, the demand for lithium ion battery industry has grown tremendously. The traditional wet preparation of Co3O4 powder cannot meet the requirements of the battery industry. Exploring suitable methods and theories for controlling particle size and morphology is of great significance for the preparation of battery-grade Co3O4 powder. CoCl2 was used as the cobalt source, NH4HCO3 was used as the precipitant, and the precursor was prepared and further calcined to obtain Co3O4 powder. The results show that the molar ratio is the main factor affecting the precursor phase in the preparation of Co3O4 in CoCl2-NH4HCO3 system. The suitable process conditions for the system are a molar ratio of NH4HCO3 to CoCl2 of 4.5:1, a concentration of CoCl2 of 13 g/L, a reaction temperature of 600C, and a reaction time of 10 hours. The median diameter of Co3O4 prepared by the reaction conditions is about 9 μm.展开更多
Ultralong titanyl phthalocyanine (TiOPc) sub-micron wires have been synthesized by a novel solution-based self- assembly method. By using different solvents, changing the mass concentration and the solvent vapor pre...Ultralong titanyl phthalocyanine (TiOPc) sub-micron wires have been synthesized by a novel solution-based self- assembly method. By using different solvents, changing the mass concentration and the solvent vapor pressure, the length and the shape of the wires can be adjusted. The mixed-phase properties of the TiOPc sub-micron wires were investigated by the ultraviolet-visible (UV-vis) absorption spectrum and X-ray diffraction. Organic transistors based on these wires were studied, which show the typical p-channel characteristics.展开更多
More than 40%of newly discovered drugs have little or no water solubility which presents a serious challenge to the successful development and commercialization of new drugs in the pharmaceutical industry.Additionally...More than 40%of newly discovered drugs have little or no water solubility which presents a serious challenge to the successful development and commercialization of new drugs in the pharmaceutical industry.Additionally,more than 90%of drugs approved since 1995 have poor solubility,poor permeability,or both.Therefore,it may be necessary to increase the dose of a poorly soluble drug to obtain the required efficacy which can lead to more side effects and higher cost to the patient.Performance of drugs can be improved by decreasing the particle size and,at the same time,increasing specific surface area,dissolution rate and the bioavailability of the drug in the human body.The routes of administration are different and listed as 60%for oral,5%for pulmonary,5%for ocular,5%for topical and 25%for injectable,approximately.The injectable drugs are the most interesting ones for nanoization,because smaller particles will increase performance,and will be useful when using micro needles.In a typical manufacturing process of APIs(active pharmaceutical ingredients)top down processes like high pressure homogenization and wet bead milling are used as standard methods to decrease the particle sizes down to a fineness range of 10 to 500 nanometers.展开更多
Pattem imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is inves- tigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiat...Pattem imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is inves- tigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ASNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device.展开更多
Scale-up synthesis of sub-micron ZSM-5 molecular sieve in a quasi-solid system was investigated. Compared with traditional hydrothermal synthesis, the synthesis in a quasi-solid system has the advantages of high yield...Scale-up synthesis of sub-micron ZSM-5 molecular sieve in a quasi-solid system was investigated. Compared with traditional hydrothermal synthesis, the synthesis in a quasi-solid system has the advantages of high yield, short crystallization time, low energy consumption as well as low emissions. However, the high solid content in the quasi-solid system can cause the mass and heat transfer problems and make scalable production difficult. In order to solve the problem, we have developed a method for the optimization of the mass and heat transfer. By this method one can vary the flow field in the reactor by changing the stirrer speed. Scale-up synthesis of the sub-micron ZSM-5 molecular sieve in a quasi-solid system was carried out in a 5 L reactor with double propeller-type agitators. The process was investigated with product characterization using X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the flow field information was collected using laser Doppler velocimetry (LDV). The results showed that the flow field patterns can be tuned by using different stirrer speeds, the morphology and size of assynthesized of ZSM-5 can be effectively controlled.展开更多
文摘Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon dioxide with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in super-critical CO2 with cosolvent acetone was measured using a dynamic apparatus at pressures between 12 and 32 MPa,temperatures at 313, 323 and 333 K and cosolvent concentration at 1.5, 3.0, 4.5 and 6.0% (by mole). The effect of pre-expansion pressure, extraction temperature, spraying distance, nozzle size and concentration of cosolvent on the precipitated particles was investigated. The results show that the mean particle size of griseofulvin precipitated by RESS was less than 1.2μm. An increase in pre-expansion pressure, extraction temperature, spraying distance and concentration of cosolvent resulted in a decrease in particle size under the operating condition studied. With the decrease of nozzle diameter the particle size reduces. The crystallinity and melting point of the original material and the processed particle by RESS were tested by X-ray diffraction (XRD) and differential scanning calorimetry (DSC).No evident modification in the crystal habit was found under the experimental conditions tested. The morphology of particles precipitated was analyzed bY scanning electron microscopy (SEM).
基金Project(50878080)supported by the National Natural Science Foundation of ChinaProject(K0902006-31)supported by the Key Scientific and Technological Special of Changsha City in China
文摘The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an optimum porosity of 0.32 to get a higher efficiency and lower pressure drop during filtration.According to the results of simulation and experiment,it is evident that lower inlet velocity can maintain lower pressure drop and obtain higher collection efficiency and inlet concentration also has a crucial influence on the collection efficiency.The collection efficiency of equipment increases significantly with the increase of inlet concentration when the inlet concentration is less than 6.3 g/m3,but it gradually tends to be stable in the range of 97.3%-99.7%when the inlet concentration is over this concentration.
文摘Papaya pulp is very perishable and has a short shelf life. Manually sliced papayas were treated with 0%, 0.25%, 0.5%, and 1% chitosan (non-micronized and micronized) aqueous solutions;placed into plastic trays, and over-wrapped with PVDC film and then stored at 4°C. Color, soluble solid content, water loss, and total plate count of samples were evaluated. Chitosan coating had the ability to maintain the lightness of the sliced papayas. The a* values of the micronized chitosan-coated sliced papayas were significantly lower than those of the-coated. The sliced papayas that had been treated with 1% MC had a higher total soluble solid content and lower b* value after four days of storage. Also, the chitosan coating on the sliced papaya effectively retarded water loss and inhibited the growth of microorganisms. The results reveal that applying a chitosan coating effectively maintained the quality attributes and prolonged the shelf life of the sliced papayas.
文摘Life cycle assessment is applied to assess the ultra-clean micronized coal oil water slurry (UCMCOWS) with SimaPro and the environmental impact of UCMCOWS on its whole life cycle is also analyzed. The result shows that the consumption of energy and products are increasing along with the deepening of UCMCOWS processing, UCMCOWS making and combustion are the two periods which have a bigger impact on eco-system and human health. As a new substitute of fuel, UCMCOWS merits to be utilized more efficiently and reasonably.
基金This project is financially supported by the National Nature Science Fund (59785016) and the Opening Fund ([2000]002) of the N
文摘The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al_2O_(3p)/6061Al and the weldability of the material were studied. Experimental results indicated that because of the huge specific surface area of the reinforcement, the interfacial reaction between the matrix and the reinforcement was re- strained intenslvely at elevated temperature and pulsed laser beam. The main factor affecting the weldability of the com- posite was the reinforcement segregation in the weld resulting from the push of the liquid/solid interface during the soli- dification of the molten pool. The laser pulse frequency directly affected the reinforcement segregation and the reinfor- cement distribution in the weld, so that the weldability of the composite could be improved by increasing the laser pulse frequency. On the basis of this, a satisfactory welded joint of sub-micron paniculate-reinforced aluminum matrix com- posite Al_2O_(3p)/6061Al was obtained by using appopriate welding parameters.
文摘Marble that exploited for micronized calcite production in Nigde area (South Central Turkey) occur in the Upper Cretaceous Gümü ler, A gedi i, and Kaleboynu Formations of the Nigde Massif. Although there are a few marble producing quarries in the area, it is long been known that the marbles of this area are generally highly fractured and don’t yield large blocks or suitable slabs meeting the industrial demands. Thus, most of the production is currently carried out mainly as building stone, crushed stone and micronized calcite. Due mainly to high demand, micronized calcite has been becoming very significant export product to the state’s economy. Because the Nigde marbles are coarse grained with high CaCO3 content, high purity and whiteness, they are considered to be the highest quality micronized calcite quarries in the country. Consequently, the area drew many national and international investors resulting in significant increase in the number and extent of micronized calcite plants in the area. In early 1980’s, the city of Nigde had only one or two plants, it is now well over 5 including foreign investors and joint ventures. Annual production is also considerably increased from 20,000-30,000 tones to almost half a million tones and it is still in increasing trend.
基金The project supported by the National Science Foundation of in Anhui Province,China(No.01046201)
文摘The Experiments, methods and results of obtaining micron beam in the Microbeam Facility of the Institute of Plasma Physics were discussed in this paper. The H+2 beam was accelerated by the Van de GraafF electrostatic accelerator, and the collimator at the end of the beam line is a 60 μm thick stainless steel chip. And as a result, particle tracks on the solid track probes (CR39 film) etched in the solution of NaOH showed that the beam can go through the collimator with a small aperure (2000, 300, 55, 30, or 10 μm) and 3.5 μm thick vacuum film (Mylar). Besides the CR39 method, the beam was measured by an energy spectrum detector after the 10 μm diameter aperture and the 3.5 μm thick vacuum film too.
文摘The antioxidant activity of chitosan before micronization (BMC, average particle size of 1850 ± 26.3 μm) and after micronization (AMC, average particle size of 1.37 ± 0.2 μm) in grape juice was studied. Antioxidant activity was determined, including that of DPPH radicals, hydrogen peroxide and superoxide anion radicals, as well as ABTS radicals of BMC or AMC in grape juice. AMC exhibits stronger scavenging activity toward DPPH radicals, superoxide anion radicals and hydrogen peroxide than BMC. At a concentration of 1.0 mg/mL, AMC in grape juice exhibited 90.0%, 97.3% and 88.7% scavenging activities toward DPPH radicals, hydrogen peroxide and superoxide anion radicals, respectively. The TEAC (Trolox Equivalent Antioxidant Capacity) values of AMC (3.94 ± 0.19) greatly exceeded those of BMC (2.21 ± 0.10) in grape juice. The in vitro results in this investigation suggest the possibility that AMC can increase the antioxidant activity in grape juice. However, comprehensive studies must be performed to ascertain the in vivo safety of AMC in experimental animal models.
文摘Co3O4 powder has a wide range of applications in the fields of catalysts, magnetic materials and electrochemistry. Especially after the 1990s, the demand for lithium ion battery industry has grown tremendously. The traditional wet preparation of Co3O4 powder cannot meet the requirements of the battery industry. Exploring suitable methods and theories for controlling particle size and morphology is of great significance for the preparation of battery-grade Co3O4 powder. CoCl2 was used as the cobalt source, NH4HCO3 was used as the precipitant, and the precursor was prepared and further calcined to obtain Co3O4 powder. The results show that the molar ratio is the main factor affecting the precursor phase in the preparation of Co3O4 in CoCl2-NH4HCO3 system. The suitable process conditions for the system are a molar ratio of NH4HCO3 to CoCl2 of 4.5:1, a concentration of CoCl2 of 13 g/L, a reaction temperature of 600C, and a reaction time of 10 hours. The median diameter of Co3O4 prepared by the reaction conditions is about 9 μm.
基金supported by the National Natural Science Foundation of China(Grant No.61176021)the Innovation Group Project from Shanghai EducationCommission,China
文摘Ultralong titanyl phthalocyanine (TiOPc) sub-micron wires have been synthesized by a novel solution-based self- assembly method. By using different solvents, changing the mass concentration and the solvent vapor pressure, the length and the shape of the wires can be adjusted. The mixed-phase properties of the TiOPc sub-micron wires were investigated by the ultraviolet-visible (UV-vis) absorption spectrum and X-ray diffraction. Organic transistors based on these wires were studied, which show the typical p-channel characteristics.
文摘More than 40%of newly discovered drugs have little or no water solubility which presents a serious challenge to the successful development and commercialization of new drugs in the pharmaceutical industry.Additionally,more than 90%of drugs approved since 1995 have poor solubility,poor permeability,or both.Therefore,it may be necessary to increase the dose of a poorly soluble drug to obtain the required efficacy which can lead to more side effects and higher cost to the patient.Performance of drugs can be improved by decreasing the particle size and,at the same time,increasing specific surface area,dissolution rate and the bioavailability of the drug in the human body.The routes of administration are different and listed as 60%for oral,5%for pulmonary,5%for ocular,5%for topical and 25%for injectable,approximately.The injectable drugs are the most interesting ones for nanoization,because smaller particles will increase performance,and will be useful when using micro needles.In a typical manufacturing process of APIs(active pharmaceutical ingredients)top down processes like high pressure homogenization and wet bead milling are used as standard methods to decrease the particle sizes down to a fineness range of 10 to 500 nanometers.
文摘Pattem imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is inves- tigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ASNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device.
文摘Scale-up synthesis of sub-micron ZSM-5 molecular sieve in a quasi-solid system was investigated. Compared with traditional hydrothermal synthesis, the synthesis in a quasi-solid system has the advantages of high yield, short crystallization time, low energy consumption as well as low emissions. However, the high solid content in the quasi-solid system can cause the mass and heat transfer problems and make scalable production difficult. In order to solve the problem, we have developed a method for the optimization of the mass and heat transfer. By this method one can vary the flow field in the reactor by changing the stirrer speed. Scale-up synthesis of the sub-micron ZSM-5 molecular sieve in a quasi-solid system was carried out in a 5 L reactor with double propeller-type agitators. The process was investigated with product characterization using X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the flow field information was collected using laser Doppler velocimetry (LDV). The results showed that the flow field patterns can be tuned by using different stirrer speeds, the morphology and size of assynthesized of ZSM-5 can be effectively controlled.