Abstract： The dynamic spheroidization kinetics behavior of Ti-6.5Al-2Zr-1Mo-1V alloy with a lamellar initial microstructure was studied by isothermal hot compression tests in the temperature range of 750-950℃ and st...Abstract： The dynamic spheroidization kinetics behavior of Ti-6.5Al-2Zr-1Mo-1V alloy with a lamellar initial microstructure was studied by isothermal hot compression tests in the temperature range of 750-950℃ and strain rates of 0.001-10 s^-1. The results show that the spheroidized fraction of alpha lamellae increases with the increase of temperature and the decrease of strain rate. The spheroidization kinetics curves predicted by JMAK equation agree well with experimental ones. The corresponding SEM and TEM observations indicate that the dynamic spheroidization process can be divided into two stages. The primary stage is boundary splitting formed by two competing mechanisms which are dynamic recrystallization and mechanical twin. In the second stage, the penetration of beta phase into the alpha/alpha grain boundaries is dominant, which is controlled in nature by diffusion of the chemical elements such as Al, Mo and V.展开更多
The photodissociation dynamics of isocyanic acid （HNCO） has been studied by the time- sliced velocity map ion imaging technique at 193 nm. The NH（a1△） products were measured via （2＋1） resonance enhanced multip...The photodissociation dynamics of isocyanic acid （HNCO） has been studied by the time- sliced velocity map ion imaging technique at 193 nm. The NH（a1△） products were measured via （2＋1） resonance enhanced multiphoton ionization. Images have been accumulated for the NH（a1△） rotational states in the ground and vibrational excited state （v=0 and 1）. The center-of-mass translational energy distribution derived from the NH（a1△） images implies that the CO vibrational distributions are inverted for most of the measured 1NH（v｜j） internal states. The anisotropic product angular distribution observed indicates a rapid dissociation process for the N-C bond cleavage. A bimodal rotational state distribution of CO（v） has been observed, this result implies that isocyanic acid dissociates in the S1 state in two different pathways.展开更多
Ahn To develop a high resolution HPLC method for the determination of ondansetron in human plasma and to study the pharmacokinetics of ondansetron in orally disintegrating tablets. Methods HPLC determination involved ...Ahn To develop a high resolution HPLC method for the determination of ondansetron in human plasma and to study the pharmacokinetics of ondansetron in orally disintegrating tablets. Methods HPLC determination involved liquid-liquid extraction, separation on a CN column and ultraviolet detection at 310 ran with granisetron as an internal standard. Pharmacokinetics and bioequivalence of ondansetron in orally disintegrating tablets by direct compression and conventional 8 mg tablets were evaluated and compared in 20 healthy human male volunteers after a single oral dose in a randomized cross-over study. Results The limit of quantification was 0.25 ng· mL^-1. The recovery was about 85 % or over for ondan setron and about 90% for internal standard. Linearity was good within the concentration range of 0.5 - 50 ng·mL^-1 with r^2 ranging from 0.997 1 to 0.999 9. Intra- and inter-assay coefficients of variation ranged from 1.78% to 2.38% and 3.88% -5.19%, respectively. Accuracies for spiked concentrations of 2.0, 10.0, and 30.0 ng·mL^-1 were 104.7% ±4.4%, 102.2% ± 1.1%, and99.51% ±2.34%, respectively. Pharmacokinetic parameters of AUCo-t, AUCo-∞ , Cmax, Tmax, and T1/2 were 230.2 ± 78.0 ng·h·L^-1 , 265.2± 101.5 ng·h·mL^-1, 35.67 ± 8.94 ng·mL^-l, 1.51 ±0.79 h, and 5.00± 1.41 h for orally disintegrating tablets, respectively. The analysis of variance did not show any significant difference between orally disintegrating tablets and conventional tablets, and 90% confidence intervals fell within the acceptable range for bioequivalence. Conclusion High resolution HPLC method has been set up and applied in pharmacokinetic evaluation of ondansetron in orally disintegrating tablets.展开更多
Aim To prepare the sustained release melatonin tablet with HPMC matrix and study its pharmacokinetics and bioavailatility. Methods HPMC was used as matrix to formulate the sustained release tablet. The influences of t...Aim To prepare the sustained release melatonin tablet with HPMC matrix and study its pharmacokinetics and bioavailatility. Methods HPMC was used as matrix to formulate the sustained release tablet. The influences of the size of melatonin, type and amount of HPMC, drug loading, type and amount of additives, and compressing pressure were investigated. Plasma concentration of melatonin in dogs after intravenous injection of two doses and oral administration of sustained release tablets and unmodified release capsules was detected by HPLC using fluorescence detector. Results The drug release from sustained release tablets was influenced by the size of melatonin, type and amount of HPMC, drug loading, and type and amount of additives. Melatonin was found to fit two compartment model after intravenous injection, AUC was proportional to doses, and t(1/2β) of two doses has no significant difference. Relative bioavailability of melatonin sustained release tablet to normal capsule was 83.8%, and absolute bioavailability was 3.75% for sustained release tablet and 4.49% for capsule. Conclusion The melatonin sustained release tablet was well formulated. The absolute bioavilability for oral administration of either sustained release tablet or unmodified release capsule of melatonin was less than 5%. The bioavailability of melatonin sustained release tablet was lower than that of unmodified release capsule, but MRT of sustained release tablet was significantly longer than that of capsule.展开更多
A novel floating osmotic pump controlled release system （FOP） and traditional matrix sustained release tablets （MT） of dipyridamole （DIP） were characterized in terms of pharmacokinetics, drug release, and in vit...A novel floating osmotic pump controlled release system （FOP） and traditional matrix sustained release tablets （MT） of dipyridamole （DIP） were characterized in terms of pharmacokinetics, drug release, and in vitro-in vivo correlation. In vivo study was performed by a three-crossover study in six beagle dogs relative to the conventional tablet （CT）. A HPLC method for the determination of DIP in the plasma was developed. Cumulative percent of absorption fraction was compared to that of in vitro cumulative release. Both FOP and MT displayed obvious extended release characteristic in vivo while FOP showed a better extended release behavior. The bioavailability of FOP was higher than that of MT and a zero-order release linear correlation of DIP between fraction absorbed in vivo and fraction dissolved in vitro was established for FOP while not for MT. The results indicated the existence of an absorption window in upper part of the GI track of DIP, which meant that floating system could be excellent for the drug delivery. In addition, the in vitro model was a good choice for depicting in vivo absorption and for optimization of the formulation of FOP if it is needed to be bio-equivalent to MT.展开更多
The biological aerated filter （BAF） was used to treat the oil-field produced water. The removal efficiency for oil, COD, BOD and suspended solids （SS） was 76.3%-80.3%, 31.6%-57.9%, 8.6.3%-96.3% and76.4%--82.7%, re...The biological aerated filter （BAF） was used to treat the oil-field produced water. The removal efficiency for oil, COD, BOD and suspended solids （SS） was 76.3%-80.3%, 31.6%-57.9%, 8.6.3%-96.3% and76.4%--82.7%, respectively when the hydraulic loading rates varied from 016m·h^-1 to 1.4m·h^-1. The greatest partof removal, for example more than 80% of COD removal, occurred on the top 100cm of the media in BAF. The kinetic .performance of BAF indicated that the relationship of BOD removal efficiency with the hydraulic loadingrates, in biological aerated filters could be described by c1/c1=l-exp（-2.44/L^0.59）. This equation could be used topredict the B OD.removal efficiency at different hydraulic loading rates.展开更多
The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg)...The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg) and immediate release tablets (IRMS, 20 mg). The plasma concentration of morphine was determined by GC MS. The pharmacokinetic parameters of controlled release tablets and immediate release tablets were calculated∶ C max was 19.38±3.80 and 21.27±6.21 ng/ml, t max was 2.36 ±0.37 h and 0.56±0.16 h, t 1/2β was 3.53±0.87 and 3.03±0.74 h, AUC was 145.15±17.65 and 93.08±16.65 ng/ml, respectively. The steady state plasma concentration of morphine sulphate in cancer patients after multiple doses was achieved, C max of CRMS and IRMS was 27.43±0.33 ng/ml and 22.68±0.16 ng/ml, C min of CRMS and IRMS was 19.45±1.44 ng/ml and 18.14±0.49 ng/ml, respectively.展开更多
To investigate the pharmacokinetic characteristics of moclobemide sustainedrelease tablets after multiple oral dose administration in healthy Chinese volunteers. MethodsMoclobemide sustained release tablets were given...To investigate the pharmacokinetic characteristics of moclobemide sustainedrelease tablets after multiple oral dose administration in healthy Chinese volunteers. MethodsMoclobemide sustained release tablets were given as a multiple oral dose regimen of 300 mg oncedaily for five consecutive days to 12 healthy volunteers. The concentrations of moclobemide inplasma were determined by reversed-phase high performance liquid chromatography. The partialpharmacokinetic parameters were calculated using 3p97 pharmacokinetic program. Results Theconcentration-time profile fitted an one-compartment model best. The steady-state pharmacokineticparameters of moclobemide sustained release tablets after multiple oral doses were as follows:C_(max) was (1 950 +- 156) μg· L^(-1), T_(max) was (6.00 +-1.55) h, T_(1/2(kel)) was (3.14 +-0.12)h, AUC_(ss 0-24) was (22 836 +- 1 842) μg·h· L^(-1), MRT was (7.68+-0.36) h, CL/F_((s)) was(20.2+-2.1) L·h^(-1), and V/F_((c)) was (91.4+-9.4) L, respectively. No marked adverse events werenoted during this study. Conclusion The formulation has a sustained-release effect and goodtolerance in the healthy volunteers, which provides useful information for clinical practice.展开更多
The objective of marine propeller design optimization study is to obtain a propeller with minimum power absorption, maximum efficiency and good materials resistance. In this study, results of numerical simulation carr...The objective of marine propeller design optimization study is to obtain a propeller with minimum power absorption, maximum efficiency and good materials resistance. In this study, results of numerical simulation carried out on the flow around a conventional marine propeller are presented. The investigation focused on the aspects related to the influence of skew magnitude, thickness and blade number on the propeller performances. First, open water performances of a conventional propeller model DTMB 4148 was estimated using RANS （Reynolds Averaged Navier-Stokes） method. The flow around rotating propeller model was analyzed in the steady state using RANS approach of the commercial CFD （computational fluid dynamics） code fluent. The results provide good agreement with literature data. Numerical results show that the number of blades has an influence on the open water performances of marine propellers. It＇s noticed that the best propeller has four or five blades from only the hydrodynamic aspect. The thickness blade effect has been studied for the same propeller model and compared to the blade with three different thickness values. Results of the calculation show that the blade thickness increases moderately the propeller efficiency. Finally, numerical simulation is performed to study the magnitude skew effect on the propeller blade performance, so three different models were generated. The results of the simulation show that the skew distribution has a positive effect on the open water performances of the marine propellers.展开更多
Contra-rotating axial flow fan is a kind of the vital equipment in coal mines. Their work conditions directly affect the safety of staff and production. In the paper, the performance of the contra-rotating axial flow ...Contra-rotating axial flow fan is a kind of the vital equipment in coal mines. Their work conditions directly affect the safety of staff and production. In the paper, the performance of the contra-rotating axial flow fan is experi- mentally investigated. The study is focused on the fan performance, the shaft power and the match between the motor and fan efficiency at different blade angles. The results show that the blade angle 43°/26° has the best aerodynamic perfor- mance. The first engine has a greater impact on the fan than the second one. The blade angle with the best aerodynamic performance does not necessarily correspond to the one with the best match between the motor and fan efficiency. The blade angle 43°/24° is the best choice for the operation of the fan in the present study.展开更多
基金Project(2014ZE56015)supported by Aeronautical Science Foundation of ChinaProject(51261020)supported by the National Natural Science Foundation of ChinaProject(Zk201001004)supported by the Open Fund of the Aeronautical Science and Technology Key Laboratory of Aeronautical Material Hot Processing Technology,China
文摘Abstract： The dynamic spheroidization kinetics behavior of Ti-6.5Al-2Zr-1Mo-1V alloy with a lamellar initial microstructure was studied by isothermal hot compression tests in the temperature range of 750-950℃ and strain rates of 0.001-10 s^-1. The results show that the spheroidized fraction of alpha lamellae increases with the increase of temperature and the decrease of strain rate. The spheroidization kinetics curves predicted by JMAK equation agree well with experimental ones. The corresponding SEM and TEM observations indicate that the dynamic spheroidization process can be divided into two stages. The primary stage is boundary splitting formed by two competing mechanisms which are dynamic recrystallization and mechanical twin. In the second stage, the penetration of beta phase into the alpha/alpha grain boundaries is dominant, which is controlled in nature by diffusion of the chemical elements such as Al, Mo and V.
基金supported by the National Natural Science Foundation of China(No.21573227,N0.11604052)the National Science Foundation of Anhui Province of China(No.1608085QA19)+2 种基金the Natural Science Research Project of Education Department of Anhui Province of China(No.2014KJ020)the Open Foundation of State Key Laboratory(No.SKLMRDK201503,No.SKLMRD-K201611,and No.SKLMRDK201711)the Doctoral Foundation of Fuyang Normal University(No.FSB201501005)
文摘The photodissociation dynamics of isocyanic acid （HNCO） has been studied by the time- sliced velocity map ion imaging technique at 193 nm. The NH（a1△） products were measured via （2＋1） resonance enhanced multiphoton ionization. Images have been accumulated for the NH（a1△） rotational states in the ground and vibrational excited state （v=0 and 1）. The center-of-mass translational energy distribution derived from the NH（a1△） images implies that the CO vibrational distributions are inverted for most of the measured 1NH（v｜j） internal states. The anisotropic product angular distribution observed indicates a rapid dissociation process for the N-C bond cleavage. A bimodal rotational state distribution of CO（v） has been observed, this result implies that isocyanic acid dissociates in the S1 state in two different pathways.
文摘Ahn To develop a high resolution HPLC method for the determination of ondansetron in human plasma and to study the pharmacokinetics of ondansetron in orally disintegrating tablets. Methods HPLC determination involved liquid-liquid extraction, separation on a CN column and ultraviolet detection at 310 ran with granisetron as an internal standard. Pharmacokinetics and bioequivalence of ondansetron in orally disintegrating tablets by direct compression and conventional 8 mg tablets were evaluated and compared in 20 healthy human male volunteers after a single oral dose in a randomized cross-over study. Results The limit of quantification was 0.25 ng· mL^-1. The recovery was about 85 % or over for ondan setron and about 90% for internal standard. Linearity was good within the concentration range of 0.5 - 50 ng·mL^-1 with r^2 ranging from 0.997 1 to 0.999 9. Intra- and inter-assay coefficients of variation ranged from 1.78% to 2.38% and 3.88% -5.19%, respectively. Accuracies for spiked concentrations of 2.0, 10.0, and 30.0 ng·mL^-1 were 104.7% ±4.4%, 102.2% ± 1.1%, and99.51% ±2.34%, respectively. Pharmacokinetic parameters of AUCo-t, AUCo-∞ , Cmax, Tmax, and T1/2 were 230.2 ± 78.0 ng·h·L^-1 , 265.2± 101.5 ng·h·mL^-1, 35.67 ± 8.94 ng·mL^-l, 1.51 ±0.79 h, and 5.00± 1.41 h for orally disintegrating tablets, respectively. The analysis of variance did not show any significant difference between orally disintegrating tablets and conventional tablets, and 90% confidence intervals fell within the acceptable range for bioequivalence. Conclusion High resolution HPLC method has been set up and applied in pharmacokinetic evaluation of ondansetron in orally disintegrating tablets.
文摘Aim To prepare the sustained release melatonin tablet with HPMC matrix and study its pharmacokinetics and bioavailatility. Methods HPMC was used as matrix to formulate the sustained release tablet. The influences of the size of melatonin, type and amount of HPMC, drug loading, type and amount of additives, and compressing pressure were investigated. Plasma concentration of melatonin in dogs after intravenous injection of two doses and oral administration of sustained release tablets and unmodified release capsules was detected by HPLC using fluorescence detector. Results The drug release from sustained release tablets was influenced by the size of melatonin, type and amount of HPMC, drug loading, and type and amount of additives. Melatonin was found to fit two compartment model after intravenous injection, AUC was proportional to doses, and t(1/2β) of two doses has no significant difference. Relative bioavailability of melatonin sustained release tablet to normal capsule was 83.8%, and absolute bioavailability was 3.75% for sustained release tablet and 4.49% for capsule. Conclusion The melatonin sustained release tablet was well formulated. The absolute bioavilability for oral administration of either sustained release tablet or unmodified release capsule of melatonin was less than 5%. The bioavailability of melatonin sustained release tablet was lower than that of unmodified release capsule, but MRT of sustained release tablet was significantly longer than that of capsule.
文摘A novel floating osmotic pump controlled release system （FOP） and traditional matrix sustained release tablets （MT） of dipyridamole （DIP） were characterized in terms of pharmacokinetics, drug release, and in vitro-in vivo correlation. In vivo study was performed by a three-crossover study in six beagle dogs relative to the conventional tablet （CT）. A HPLC method for the determination of DIP in the plasma was developed. Cumulative percent of absorption fraction was compared to that of in vitro cumulative release. Both FOP and MT displayed obvious extended release characteristic in vivo while FOP showed a better extended release behavior. The bioavailability of FOP was higher than that of MT and a zero-order release linear correlation of DIP between fraction absorbed in vivo and fraction dissolved in vitro was established for FOP while not for MT. The results indicated the existence of an absorption window in upper part of the GI track of DIP, which meant that floating system could be excellent for the drug delivery. In addition, the in vitro model was a good choice for depicting in vivo absorption and for optimization of the formulation of FOP if it is needed to be bio-equivalent to MT.
基金Supported by the National Natural Science Foundation of China （No.59978020）.
文摘The biological aerated filter （BAF） was used to treat the oil-field produced water. The removal efficiency for oil, COD, BOD and suspended solids （SS） was 76.3%-80.3%, 31.6%-57.9%, 8.6.3%-96.3% and76.4%--82.7%, respectively when the hydraulic loading rates varied from 016m·h^-1 to 1.4m·h^-1. The greatest partof removal, for example more than 80% of COD removal, occurred on the top 100cm of the media in BAF. The kinetic .performance of BAF indicated that the relationship of BOD removal efficiency with the hydraulic loadingrates, in biological aerated filters could be described by c1/c1=l-exp（-2.44/L^0.59）. This equation could be used topredict the B OD.removal efficiency at different hydraulic loading rates.
文摘The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg) and immediate release tablets (IRMS, 20 mg). The plasma concentration of morphine was determined by GC MS. The pharmacokinetic parameters of controlled release tablets and immediate release tablets were calculated∶ C max was 19.38±3.80 and 21.27±6.21 ng/ml, t max was 2.36 ±0.37 h and 0.56±0.16 h, t 1/2β was 3.53±0.87 and 3.03±0.74 h, AUC was 145.15±17.65 and 93.08±16.65 ng/ml, respectively. The steady state plasma concentration of morphine sulphate in cancer patients after multiple doses was achieved, C max of CRMS and IRMS was 27.43±0.33 ng/ml and 22.68±0.16 ng/ml, C min of CRMS and IRMS was 19.45±1.44 ng/ml and 18.14±0.49 ng/ml, respectively.
文摘To investigate the pharmacokinetic characteristics of moclobemide sustainedrelease tablets after multiple oral dose administration in healthy Chinese volunteers. MethodsMoclobemide sustained release tablets were given as a multiple oral dose regimen of 300 mg oncedaily for five consecutive days to 12 healthy volunteers. The concentrations of moclobemide inplasma were determined by reversed-phase high performance liquid chromatography. The partialpharmacokinetic parameters were calculated using 3p97 pharmacokinetic program. Results Theconcentration-time profile fitted an one-compartment model best. The steady-state pharmacokineticparameters of moclobemide sustained release tablets after multiple oral doses were as follows:C_(max) was (1 950 +- 156) μg· L^(-1), T_(max) was (6.00 +-1.55) h, T_(1/2(kel)) was (3.14 +-0.12)h, AUC_(ss 0-24) was (22 836 +- 1 842) μg·h· L^(-1), MRT was (7.68+-0.36) h, CL/F_((s)) was(20.2+-2.1) L·h^(-1), and V/F_((c)) was (91.4+-9.4) L, respectively. No marked adverse events werenoted during this study. Conclusion The formulation has a sustained-release effect and goodtolerance in the healthy volunteers, which provides useful information for clinical practice.
文摘The objective of marine propeller design optimization study is to obtain a propeller with minimum power absorption, maximum efficiency and good materials resistance. In this study, results of numerical simulation carried out on the flow around a conventional marine propeller are presented. The investigation focused on the aspects related to the influence of skew magnitude, thickness and blade number on the propeller performances. First, open water performances of a conventional propeller model DTMB 4148 was estimated using RANS （Reynolds Averaged Navier-Stokes） method. The flow around rotating propeller model was analyzed in the steady state using RANS approach of the commercial CFD （computational fluid dynamics） code fluent. The results provide good agreement with literature data. Numerical results show that the number of blades has an influence on the open water performances of marine propellers. It＇s noticed that the best propeller has four or five blades from only the hydrodynamic aspect. The thickness blade effect has been studied for the same propeller model and compared to the blade with three different thickness values. Results of the calculation show that the blade thickness increases moderately the propeller efficiency. Finally, numerical simulation is performed to study the magnitude skew effect on the propeller blade performance, so three different models were generated. The results of the simulation show that the skew distribution has a positive effect on the open water performances of the marine propellers.
文摘Contra-rotating axial flow fan is a kind of the vital equipment in coal mines. Their work conditions directly affect the safety of staff and production. In the paper, the performance of the contra-rotating axial flow fan is experi- mentally investigated. The study is focused on the fan performance, the shaft power and the match between the motor and fan efficiency at different blade angles. The results show that the blade angle 43°/26° has the best aerodynamic perfor- mance. The first engine has a greater impact on the fan than the second one. The blade angle with the best aerodynamic performance does not necessarily correspond to the one with the best match between the motor and fan efficiency. The blade angle 43°/24° is the best choice for the operation of the fan in the present study.
