Conversion of biomass to chemicals or fuels under mild condition is still a challenge. As a platform molecule for chemicals and fuels, levulinic acid （LA） has been prepared by lique-faction of biomass at high pressu...Conversion of biomass to chemicals or fuels under mild condition is still a challenge. As a platform molecule for chemicals and fuels, levulinic acid （LA） has been prepared by lique-faction of biomass at high pressure. In order to carry out the conversion from wheat straw to LA at atmosphere pressure, continuous extraction of the reactive system by an organic solvent with a higher density than that of water was utilized for degradation of pretreated biomass. Yields of LA were measured by means of gas chromatography-mass spectrometry and nuclear magnetic resonance. The results revealed that a maximum yield of 30.66% of LA can be obtained from wheat straw. In addition, the effects of biomass pretreated conditions on the LA conversion have been studied. The study provides a new route to convert biomass to valuable chemicals at atmosphere pressure.展开更多
Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A mode...Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A model for overall dispersed side volumetric mass transfer coefficients was derived by describing the motion of the drops based upon Navier-Stokes equation combined with the relationship between mass transfer coefficients and the drop velocity. The model provides good predictions and can be successfully used in aqueous two-phase extraction. The average relative deviation between calculated values and experimental data ranges from 8% to 14%.展开更多
Based on batch extraction, improved liquid-impeled loop reactor(LLR) was used in continuous pilot-plant extraction for cadmium recovery from aqueous wastes. It integrated emulsifying, extracting, separating and demuls...Based on batch extraction, improved liquid-impeled loop reactor(LLR) was used in continuous pilot-plant extraction for cadmium recovery from aqueous wastes. It integrated emulsifying, extracting, separating and demulsifying. The results showed that the extracting efficiencies were better than those of batch one and surfactant concentration was decreased to 3.0 percent from 4.0 percent of batch extraction.展开更多
In this paper we consider an evolutionary continuous casting problem with convection partial derivative + b(y) chi - Delta kappa(u) + (v) over right arrow .del u = 0 coupled with Stokes equation in the liquid phase pa...In this paper we consider an evolutionary continuous casting problem with convection partial derivative + b(y) chi - Delta kappa(u) + (v) over right arrow .del u = 0 coupled with Stokes equation in the liquid phase partial derivative(t) (v) over right arrow - v Delta (v) over right arrow + del p = (f) over right arrow(u) The mixed boundary condition is put on temprature. The existence of a weak solution is obtained by using methods of regularization, temperature dependent penalty form in the Stokes equation and compact arguments.展开更多
The continuous affinity- recycle extraction (CARE) process is extended ic a system with ultrafiltration membranes. The mathematical model of the process is established by taking into account membrane rejections to th...The continuous affinity- recycle extraction (CARE) process is extended ic a system with ultrafiltration membranes. The mathematical model of the process is established by taking into account membrane rejections to the components in a crude mixture. The process performance, defined as concentration factor (CF ), purification factor (PF ) and recovery yield (REC), is analyzed by computer simulations. The results show that CF and REC increase, but PF decreases with the membrane rejection. It is likely that optimum operating conditions exist to give the best process performance because the increases in eluant and affinity-recycle flow rate improve REC but decrease PF.展开更多
Continuous manufacturing is considered as one of the future trends of pharmaceutical engineering. In this work, continuous liquid-liquid extraction for sinomenine purification was realized with the usage of centrifuga...Continuous manufacturing is considered as one of the future trends of pharmaceutical engineering. In this work, continuous liquid-liquid extraction for sinomenine purification was realized with the usage of centrifugal extractors. Chloroform was used as the extractant because of the high distribution coefficient (>100). Higher extraction ratio can be obtained when using the centrifugal extractor of Model CWL50-N. The extraction ratio of the second-stage extraction was higher than that of the first-stage extraction. The extraction ratio of the second-stage countercurrent extraction was higher than that of second-stage cross-flow extraction. When chloroform phase was recycled for liquid-liquid extraction, the extraction ratio was also higher than 95%. This work can also be an example of continuous liquid-liquid extraction for the separation of other Chinese medicine components.展开更多
A new prototype and simple low speed counter current chromatography (LSCCC) has been fabricated and a laboratory work has been carried out for rapid and continuous removal of methyl red from wastewater using xylene as...A new prototype and simple low speed counter current chromatography (LSCCC) has been fabricated and a laboratory work has been carried out for rapid and continuous removal of methyl red from wastewater using xylene as an extractant. The distribution ratio (D) and percentage of recoveries were calculated. The optimum concentration for extraction of methyl red was in the range of 2 × 10<sup>-</sup><sup>4</sup> to 8 × 10<sup>-</sup><sup>4</sup> mol·L<sup>-</sup><sup>1</sup>. Maximum extraction achieved at pH range of 2 to 4.5. Various dye concentrations and solvent effects were studied to optimized conditions. It was shown that when the ratio of the organic phase to aqueous phase increased to more than 3:1, the striping efficiency decreased sharply. The experiments were carried out for 5 times and the highest extraction achieved was 99.8 per cent by two-solvent system LSCCC in just 5 minutes. Real wastewater samples were analyzed and the efficiency of the technique was compared with liquid-liquid extraction (LLE). In practice it was shown that although both techniques are rapid, the efficiency of the LSCCC is much better than LLE.展开更多
Longitudinal cracks are common defects of continuous casting slabs and may lead to serious quality accidents. Image capturing and recognition of hot slabs is an effective way for on-line detection of cracks, and recog...Longitudinal cracks are common defects of continuous casting slabs and may lead to serious quality accidents. Image capturing and recognition of hot slabs is an effective way for on-line detection of cracks, and recognition of cracks is essential because the surface of hot slabs is very complicated. In order to detect the surface longitudinal cracks of the slabs, a new feature extraction method based on Curvelet transform and kernel locality preserving projections （KLPP） is proposed. First, sample images are decomposed into three levels by Curvelet transform. Second, Fourier transform is applied to all sub-band images and the Fourier amplitude spectrum of each sub-band is computed to get features with translational invariance. Third, five kinds of statistical features of the Fourier amplitude spectrum are computed and combined in different forms. Then, KLPP is employed for dimensionality reduction of the obtained 62 types of high-dimensional combined features. Finally, a support vector machine （SVM） is used for sample set classification. Experiments with samples from a real production line of continuous casting slabs show that the algorithm is effective to detect longitudinal cracks, and the classification rate is 91.89%.展开更多
An acidic mixture of sulfuric and fluosilicic acid(H_(2)SO_(4)+H_(2)SiF_(6))was employed as lixiviant to enhance leaching of lithium from lepidolite.The H_(2)SiF_(6) was obtained as a byproduct of anhydrous hydrofluor...An acidic mixture of sulfuric and fluosilicic acid(H_(2)SO_(4)+H_(2)SiF_(6))was employed as lixiviant to enhance leaching of lithium from lepidolite.The H_(2)SiF_(6) was obtained as a byproduct of anhydrous hydrofluoric acid production,aiming to provide HF molecules.It was found that the HF molecules were the main reaction component and played a key role in strengthening the dissolution of lepidolite.Different factors,including mass ratio of ore/H_(2)SO_(4)/H_(2)SiF_(6),concentrations of H_(2)SO_(4) and H_(2)SiF_(6),leaching temperatures(40−80℃)and time(15−75 min),were investigated.Moreover,an efficient tubular reactor was employed to improve this acid leaching system.Under the optimal conditions(ore/H_(2)SO_(4)/H_(2)SiF_(6) mass ratio of 1:0.8:1.6,80 wt.% H_(2)SO_(4),15 wt.% H_(2)SiF_(6),80℃,15 min),97.9% of Li,96.4% of K,97.6% of Rb,96.7% of Cs and 81.4% of Al(mass fraction)were leached.Additionally,a two-step thermal process was proposed to remove fluorine of leaching slurry.This acid treatment using an acidic mixture of H_(2)SO_(4) and H_(2)SiF_(6) in a continuous tubular reactor shows potential as an alternative process to extract lithium from lepidolite.展开更多
Continuous blood glucose monitoring is important for the diagnosis,treatment,and study of diabetes. many organizations have been working on this subject in recent two decades. Glucose concentration in interstitial flu...Continuous blood glucose monitoring is important for the diagnosis,treatment,and study of diabetes. many organizations have been working on this subject in recent two decades. Glucose concentration in interstitial fluid is closely related to the blood glucose levels. Minimally invasive continuous blood glucose monitoring technology based on the glucose detection in interstitial fluid develops rapidly and gets more and more attentions from the patients and the doctors,due to its instantaneous real-time display of glucose level,"24/7"coverage,and the ability to characterize glycemic variability. According to the different detection methods,most of the continuous glucose monitoring technology could be divided into two kinds: subcutaneous implantation method and transdermal extraction method. This paper review s the recent development of minimally invasive blood glucose monitoring technology and instruments. The mainly remained challenges and related research directions are presented as well.展开更多
Rehmannia glutinosa L.is one of the important medicinal crops in China.Continuous cropping obstacle severely restricts the yield and quality of R.glutinosa,but its molecular mechanism is still unclear.In this study,wi...Rehmannia glutinosa L.is one of the important medicinal crops in China.Continuous cropping obstacle severely restricts the yield and quality of R.glutinosa,but its molecular mechanism is still unclear.In this study,with widely-planted "Wen 85-5" as an experiment material,based on the digital gene expression profiling (DGE) data of previous five stress treatments (continuous cropping,phenolic acid,salt,drought and waterlogging) and the first cropping and continuous cropping treatments of R.glutinosa in five different periods (seedling period,elongation period,early expanding period,middle expanding period and later expanding period),80 candidate genes (|log 2 ratio|≥1,FDR <0.001) specifically responding to continuous cropping obstacle in R.glutinosa were screened.Functional analysis revealed that the differentially expressed genes were involved in the secretion and endocytosis of root cells,which may suggest that the recognition and absorption of allelopathic autotoxins by the roots of R.glutinosa is an important factor that restricts the development of roots in continuous cropping of R.glutinosa.In order to accurately lock genes specifically responding to continuous cropping obstacle in R.glutinosa,continuous cropping soil extract and ferulic acid and p-hydroxybenzonic acid were used to treat aseptic plantlets of R.glutinosa,respectively,and it was confirmed through qRT-PCR that the expression levels of some genes under phenolic acid treatment changed more severely than that under the continuous cropping soil extract treatment,and four key genes involved in the response of R.glutinosa to continuous cropping were finally locked.This study lays a foundation for further exploration of the molecular mechanism of continuous cropping obstacle.展开更多
The problem of measuring exterior ballistic feature points is always difficult to solve and it is essentiale on exterior ballistic measurement.By analysis of radar reflection characteristics and non-stationary echo si...The problem of measuring exterior ballistic feature points is always difficult to solve and it is essentiale on exterior ballistic measurement.By analysis of radar reflection characteristics and non-stationary echo signals of exterior ballistic feature points,the echo data of exterior ballistic feature points is measured by using the continuous wave radar.The parameters of feature points are extracted by the empirical mode decomposition method(EMD)of Hilbert-Huang transform(HHT)spectrum analysis technique.The radar echo signal model and EMD extraction model are established to analyze the exterior ballistic mutation point detection and EMD extraction method of aliasing echo signal.Typical feature point parameters of exterior ballistic in rocket flight tests are carried out and the effectiveness of the method is verified.A new method of measuring the parameters of exterior ballistic feature point is therefore presented.展开更多
A novel extraction method of baicalin from radix scutellariae was explored in this study. Liquid-liquid continuous biphasic extraction was a new method, and showed the advantage of high extracting contents of total fl...A novel extraction method of baicalin from radix scutellariae was explored in this study. Liquid-liquid continuous biphasic extraction was a new method, and showed the advantage of high extracting contents of total flavone compared with one of the traditional methods. The novel extraction method which is easy to operate and has good reproducibility was much more effective than the traditional one.展开更多
Piperacillin/tazobactam and ciprofloxacin are often used in combination as initial empiric anti-biotic therapy in critical ill patients. Especially in patients undergoing continuous renal replacement therapy (CRRT) th...Piperacillin/tazobactam and ciprofloxacin are often used in combination as initial empiric anti-biotic therapy in critical ill patients. Especially in patients undergoing continuous renal replacement therapy (CRRT) the pharmacokinetics of antimicrobial agents can be highly variable. In order to avoid under- or overdosage of antibiotics therapeutic drug monitoring (TDM) is highly re-commendable. Based on two known HPLC assays for piperacillin a new method in combination with solid phase extraction (SPE) for the simultaneous determination of piperacillin and ciprofloxacin was developed. Method validation was performed according to the EMA guideline on validation of bioanalytical methods. The HPLC column used was a Perfect Bond ODS-HD C18 analytical column (100 mm × 4.6 mm i.d., particle size 5 μm), equipped with a guard column (10 mm × 4.6 mm, particle size 5 μm) containing the same packing material. Detection wavelength was set at 228 nm for piperacillin and benzylpenicillin was used as internal standard (IS). Ciprofloxacin was determined at two wavelengths (280 nm, 315 nm). This newly developed HPLC method in combination with SPE-extraction allows an accurate, precise, specific and efficient determination of piperacillin and ciprofloxacin in biological matrices. Results allow the calculation of all relevant pharmacokinetic data for critically ill patients undergoing CRRT and the optimization of dosing and TDM.展开更多
Continual relation extraction aims to learn newly arriving relation types while preserving previously acquired knowledge,but it remains challenging due to catastrophic forgetting and severe confusion among semanticall...Continual relation extraction aims to learn newly arriving relation types while preserving previously acquired knowledge,but it remains challenging due to catastrophic forgetting and severe confusion among semantically similar relations.To address this problem,we propose a continual relation extraction method that integrates prompt learning,feature enhancement,anchoring loss,and similarity-aware prototype contrastive learning.Specifically,relation-specific soft prompts and dynamic prompt selection are introduced to provide targeted semantic guidance for different samples.Based on the matched prompts,both relation prototypes and sample representations are further enhanced to improve feature quality and discriminability.In addition,an anchoring loss and a similarity-aware prototype contrastive objective are designed to explicitly optimize the boundaries between semantically similar relations during memory replay.Experiments on the FewRel and TACRED datasets show that the proposed method consistently outperforms representative baseline methods,especially in later task stages where continual learning becomes more challenging.Ablation studies and visualization results further verify the effectiveness of prompt-guided feature enhancement and similar-relationaware optimization.These results indicate that explicitly strengthening fine-grained semantic boundaries,in addition to preserving historical knowledge,is important for continual relation extraction,and the proposed method provides an effective solution for improving both knowledge retention and relation discrimination.展开更多
文摘Conversion of biomass to chemicals or fuels under mild condition is still a challenge. As a platform molecule for chemicals and fuels, levulinic acid （LA） has been prepared by lique-faction of biomass at high pressure. In order to carry out the conversion from wheat straw to LA at atmosphere pressure, continuous extraction of the reactive system by an organic solvent with a higher density than that of water was utilized for degradation of pretreated biomass. Yields of LA were measured by means of gas chromatography-mass spectrometry and nuclear magnetic resonance. The results revealed that a maximum yield of 30.66% of LA can be obtained from wheat straw. In addition, the effects of biomass pretreated conditions on the LA conversion have been studied. The study provides a new route to convert biomass to valuable chemicals at atmosphere pressure.
基金Supported by the National Natural Science Foundation of China.
文摘Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A model for overall dispersed side volumetric mass transfer coefficients was derived by describing the motion of the drops based upon Navier-Stokes equation combined with the relationship between mass transfer coefficients and the drop velocity. The model provides good predictions and can be successfully used in aqueous two-phase extraction. The average relative deviation between calculated values and experimental data ranges from 8% to 14%.
文摘Based on batch extraction, improved liquid-impeled loop reactor(LLR) was used in continuous pilot-plant extraction for cadmium recovery from aqueous wastes. It integrated emulsifying, extracting, separating and demulsifying. The results showed that the extracting efficiencies were better than those of batch one and surfactant concentration was decreased to 3.0 percent from 4.0 percent of batch extraction.
文摘In this paper we consider an evolutionary continuous casting problem with convection partial derivative + b(y) chi - Delta kappa(u) + (v) over right arrow .del u = 0 coupled with Stokes equation in the liquid phase partial derivative(t) (v) over right arrow - v Delta (v) over right arrow + del p = (f) over right arrow(u) The mixed boundary condition is put on temprature. The existence of a weak solution is obtained by using methods of regularization, temperature dependent penalty form in the Stokes equation and compact arguments.
文摘The continuous affinity- recycle extraction (CARE) process is extended ic a system with ultrafiltration membranes. The mathematical model of the process is established by taking into account membrane rejections to the components in a crude mixture. The process performance, defined as concentration factor (CF ), purification factor (PF ) and recovery yield (REC), is analyzed by computer simulations. The results show that CF and REC increase, but PF decreases with the membrane rejection. It is likely that optimum operating conditions exist to give the best process performance because the increases in eluant and affinity-recycle flow rate improve REC but decrease PF.
文摘Continuous manufacturing is considered as one of the future trends of pharmaceutical engineering. In this work, continuous liquid-liquid extraction for sinomenine purification was realized with the usage of centrifugal extractors. Chloroform was used as the extractant because of the high distribution coefficient (>100). Higher extraction ratio can be obtained when using the centrifugal extractor of Model CWL50-N. The extraction ratio of the second-stage extraction was higher than that of the first-stage extraction. The extraction ratio of the second-stage countercurrent extraction was higher than that of second-stage cross-flow extraction. When chloroform phase was recycled for liquid-liquid extraction, the extraction ratio was also higher than 95%. This work can also be an example of continuous liquid-liquid extraction for the separation of other Chinese medicine components.
文摘A new prototype and simple low speed counter current chromatography (LSCCC) has been fabricated and a laboratory work has been carried out for rapid and continuous removal of methyl red from wastewater using xylene as an extractant. The distribution ratio (D) and percentage of recoveries were calculated. The optimum concentration for extraction of methyl red was in the range of 2 × 10<sup>-</sup><sup>4</sup> to 8 × 10<sup>-</sup><sup>4</sup> mol·L<sup>-</sup><sup>1</sup>. Maximum extraction achieved at pH range of 2 to 4.5. Various dye concentrations and solvent effects were studied to optimized conditions. It was shown that when the ratio of the organic phase to aqueous phase increased to more than 3:1, the striping efficiency decreased sharply. The experiments were carried out for 5 times and the highest extraction achieved was 99.8 per cent by two-solvent system LSCCC in just 5 minutes. Real wastewater samples were analyzed and the efficiency of the technique was compared with liquid-liquid extraction (LLE). In practice it was shown that although both techniques are rapid, the efficiency of the LSCCC is much better than LLE.
基金Sponsored by Program for New Century Excellent Talents in University of China(NCET-08-0726)Beijing Nova Program of China(2007B027)
文摘Longitudinal cracks are common defects of continuous casting slabs and may lead to serious quality accidents. Image capturing and recognition of hot slabs is an effective way for on-line detection of cracks, and recognition of cracks is essential because the surface of hot slabs is very complicated. In order to detect the surface longitudinal cracks of the slabs, a new feature extraction method based on Curvelet transform and kernel locality preserving projections （KLPP） is proposed. First, sample images are decomposed into three levels by Curvelet transform. Second, Fourier transform is applied to all sub-band images and the Fourier amplitude spectrum of each sub-band is computed to get features with translational invariance. Third, five kinds of statistical features of the Fourier amplitude spectrum are computed and combined in different forms. Then, KLPP is employed for dimensionality reduction of the obtained 62 types of high-dimensional combined features. Finally, a support vector machine （SVM） is used for sample set classification. Experiments with samples from a real production line of continuous casting slabs show that the algorithm is effective to detect longitudinal cracks, and the classification rate is 91.89%.
基金the financial supports from Natural Science Foundation of Henan,China(No.212300410278)Henan Provincial Key Research and Development Program,China(No.212102310371)+1 种基金Henan Postdoctoral Foundation,China(No.202002020)China Postdoctoral Science Foundation(No.2020M682353).
文摘An acidic mixture of sulfuric and fluosilicic acid(H_(2)SO_(4)+H_(2)SiF_(6))was employed as lixiviant to enhance leaching of lithium from lepidolite.The H_(2)SiF_(6) was obtained as a byproduct of anhydrous hydrofluoric acid production,aiming to provide HF molecules.It was found that the HF molecules were the main reaction component and played a key role in strengthening the dissolution of lepidolite.Different factors,including mass ratio of ore/H_(2)SO_(4)/H_(2)SiF_(6),concentrations of H_(2)SO_(4) and H_(2)SiF_(6),leaching temperatures(40−80℃)and time(15−75 min),were investigated.Moreover,an efficient tubular reactor was employed to improve this acid leaching system.Under the optimal conditions(ore/H_(2)SO_(4)/H_(2)SiF_(6) mass ratio of 1:0.8:1.6,80 wt.% H_(2)SO_(4),15 wt.% H_(2)SiF_(6),80℃,15 min),97.9% of Li,96.4% of K,97.6% of Rb,96.7% of Cs and 81.4% of Al(mass fraction)were leached.Additionally,a two-step thermal process was proposed to remove fluorine of leaching slurry.This acid treatment using an acidic mixture of H_(2)SO_(4) and H_(2)SiF_(6) in a continuous tubular reactor shows potential as an alternative process to extract lithium from lepidolite.
基金supported by the National Natural Science Foundation of China (No.61176107,No.11204210,No.61428402,and No.61201039)the Key Program of Tianjin Natural Science Foundation (No.15JCZDJC36100)+1 种基金the National High Technology Research and Development Program of China (No.2012AA022602)the 111 Project of China (No.B07014)
文摘Continuous blood glucose monitoring is important for the diagnosis,treatment,and study of diabetes. many organizations have been working on this subject in recent two decades. Glucose concentration in interstitial fluid is closely related to the blood glucose levels. Minimally invasive continuous blood glucose monitoring technology based on the glucose detection in interstitial fluid develops rapidly and gets more and more attentions from the patients and the doctors,due to its instantaneous real-time display of glucose level,"24/7"coverage,and the ability to characterize glycemic variability. According to the different detection methods,most of the continuous glucose monitoring technology could be divided into two kinds: subcutaneous implantation method and transdermal extraction method. This paper review s the recent development of minimally invasive blood glucose monitoring technology and instruments. The mainly remained challenges and related research directions are presented as well.
基金Supported by National Natural Science Foundation of China(31271674)Key Research Project of Colleges and Universities in Henan Province(17A180024)
文摘Rehmannia glutinosa L.is one of the important medicinal crops in China.Continuous cropping obstacle severely restricts the yield and quality of R.glutinosa,but its molecular mechanism is still unclear.In this study,with widely-planted "Wen 85-5" as an experiment material,based on the digital gene expression profiling (DGE) data of previous five stress treatments (continuous cropping,phenolic acid,salt,drought and waterlogging) and the first cropping and continuous cropping treatments of R.glutinosa in five different periods (seedling period,elongation period,early expanding period,middle expanding period and later expanding period),80 candidate genes (|log 2 ratio|≥1,FDR <0.001) specifically responding to continuous cropping obstacle in R.glutinosa were screened.Functional analysis revealed that the differentially expressed genes were involved in the secretion and endocytosis of root cells,which may suggest that the recognition and absorption of allelopathic autotoxins by the roots of R.glutinosa is an important factor that restricts the development of roots in continuous cropping of R.glutinosa.In order to accurately lock genes specifically responding to continuous cropping obstacle in R.glutinosa,continuous cropping soil extract and ferulic acid and p-hydroxybenzonic acid were used to treat aseptic plantlets of R.glutinosa,respectively,and it was confirmed through qRT-PCR that the expression levels of some genes under phenolic acid treatment changed more severely than that under the continuous cropping soil extract treatment,and four key genes involved in the response of R.glutinosa to continuous cropping were finally locked.This study lays a foundation for further exploration of the molecular mechanism of continuous cropping obstacle.
基金Supported by the National Natural Science Foundation of China(61174219,51677192)
文摘The problem of measuring exterior ballistic feature points is always difficult to solve and it is essentiale on exterior ballistic measurement.By analysis of radar reflection characteristics and non-stationary echo signals of exterior ballistic feature points,the echo data of exterior ballistic feature points is measured by using the continuous wave radar.The parameters of feature points are extracted by the empirical mode decomposition method(EMD)of Hilbert-Huang transform(HHT)spectrum analysis technique.The radar echo signal model and EMD extraction model are established to analyze the exterior ballistic mutation point detection and EMD extraction method of aliasing echo signal.Typical feature point parameters of exterior ballistic in rocket flight tests are carried out and the effectiveness of the method is verified.A new method of measuring the parameters of exterior ballistic feature point is therefore presented.
文摘A novel extraction method of baicalin from radix scutellariae was explored in this study. Liquid-liquid continuous biphasic extraction was a new method, and showed the advantage of high extracting contents of total flavone compared with one of the traditional methods. The novel extraction method which is easy to operate and has good reproducibility was much more effective than the traditional one.
文摘Piperacillin/tazobactam and ciprofloxacin are often used in combination as initial empiric anti-biotic therapy in critical ill patients. Especially in patients undergoing continuous renal replacement therapy (CRRT) the pharmacokinetics of antimicrobial agents can be highly variable. In order to avoid under- or overdosage of antibiotics therapeutic drug monitoring (TDM) is highly re-commendable. Based on two known HPLC assays for piperacillin a new method in combination with solid phase extraction (SPE) for the simultaneous determination of piperacillin and ciprofloxacin was developed. Method validation was performed according to the EMA guideline on validation of bioanalytical methods. The HPLC column used was a Perfect Bond ODS-HD C18 analytical column (100 mm × 4.6 mm i.d., particle size 5 μm), equipped with a guard column (10 mm × 4.6 mm, particle size 5 μm) containing the same packing material. Detection wavelength was set at 228 nm for piperacillin and benzylpenicillin was used as internal standard (IS). Ciprofloxacin was determined at two wavelengths (280 nm, 315 nm). This newly developed HPLC method in combination with SPE-extraction allows an accurate, precise, specific and efficient determination of piperacillin and ciprofloxacin in biological matrices. Results allow the calculation of all relevant pharmacokinetic data for critically ill patients undergoing CRRT and the optimization of dosing and TDM.
文摘Continual relation extraction aims to learn newly arriving relation types while preserving previously acquired knowledge,but it remains challenging due to catastrophic forgetting and severe confusion among semantically similar relations.To address this problem,we propose a continual relation extraction method that integrates prompt learning,feature enhancement,anchoring loss,and similarity-aware prototype contrastive learning.Specifically,relation-specific soft prompts and dynamic prompt selection are introduced to provide targeted semantic guidance for different samples.Based on the matched prompts,both relation prototypes and sample representations are further enhanced to improve feature quality and discriminability.In addition,an anchoring loss and a similarity-aware prototype contrastive objective are designed to explicitly optimize the boundaries between semantically similar relations during memory replay.Experiments on the FewRel and TACRED datasets show that the proposed method consistently outperforms representative baseline methods,especially in later task stages where continual learning becomes more challenging.Ablation studies and visualization results further verify the effectiveness of prompt-guided feature enhancement and similar-relationaware optimization.These results indicate that explicitly strengthening fine-grained semantic boundaries,in addition to preserving historical knowledge,is important for continual relation extraction,and the proposed method provides an effective solution for improving both knowledge retention and relation discrimination.
