Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSP...Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSPS and Cry1Ab/Ac was proposed and combined with a lateral flow immunochromatographic assay,named“Dual-RPA-LFD”,to visualize the dual detection of genetically modified(GM)crops.In which,the herbicide tolerance gene CP4-EPSPS and the insect resistance gene Cry1Ab/Ac were selected as targets taking into account the current status of the most widespread application of insect resistance and herbicide tolerance traits and their stacked traits.Gradient diluted plasmids,transgenic standards,and actual samples were used as templates to conduct sensitivity,specificity,and practicality assays,respectively.The constructed method achieved the visual detection of plasmid at levels as low as 100 copies,demonstrating its high sensitivity.In addition,good applicability to transgenic samples was observed,with no cross-interference between two test lines and no influence from other genes.In conclusion,this strategy achieved the expected purpose of simultaneous detection of the two popular targets in GM crops within 20 min at 37°C in a rapid,equipmentfree field manner,providing a new alternative for rapid screening for transgenic assays in the field.展开更多
From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exh...From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.展开更多
The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,pr...The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,promoting conventional intercropping strategies in modern agriculture can prove challenging.The innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a solution.This system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable agriculture.In this article,we provide an overview of SMSI and explain how it differs from traditional intercropping.We also discuss the core principles that foster higher yields and the prospects for its future development.展开更多
The interfacial wettability and heat transfer behavior are crucial in the strip casting of high phosphorus-containing steel.A hightemperature simulation of strip casting was conducted using the droplet solidification ...The interfacial wettability and heat transfer behavior are crucial in the strip casting of high phosphorus-containing steel.A hightemperature simulation of strip casting was conducted using the droplet solidification technique with the aims to reveal the effects of phosphorus content on interfacial wettability,deposited film,and interfacial heat transfer behavior.Results showed that when the phosphorus content increased from 0.014wt%to 0.406wt%,the mushy zone enlarged,the complete solidification temperature delayed from1518.3 to 1459.4℃,the final contact angle decreased from 118.4°to 102.8°,indicating improved interfacial contact,and the maximum heat flux increased from 6.9 to 9.2 MW/m2.Increasing the phosphorus content from 0.081wt%to 0.406wt%also accelerated the film deposition rate from 1.57 to 1.73μm per test,resulting in a thickened naturally deposited film with increased thermal resistance that advanced the transition point of heat transfer from the fifth experiment to the third experiment.展开更多
Counterfeiting of modern banknotes poses a significant challenge,prompting the use of various preventive measures.One such measure is the magnetic anti-counterfeiting strip.However,due to its inherent weak magnetic pr...Counterfeiting of modern banknotes poses a significant challenge,prompting the use of various preventive measures.One such measure is the magnetic anti-counterfeiting strip.However,due to its inherent weak magnetic properties,visualizing its magnetic distribution has been a longstanding challenge.In this work,we introduce an innovative method by using a fiber optic diamond probe,a highly sensitive quantum sensor designed specifically for detecting extremely weak magnetic fields.We employ this probe to achieve high-resolution imaging of the magnetic fields associated with the RMB 50denomination anti-counterfeiting strip.Additionally,we conduct computer simulations by using COMSOL Multiphysics software to deduce the potential geometric characteristics and material composition of the magnetic region within the anti-counterfeiting strip.The findings and method presented in this study hold broader significance,extending the RMB 50 denomination to various denominations of the Chinese currency and other items that employ magnetic anti-counterfeiting strips.These advances have the potential to significantly improve and promote security measures in order to prevent the banknotes from being counterfeited.展开更多
Many spot defects were found on the surface of a cold-rolled Fe-36%Ni alloy strip produced in a factory,which seriously affected the surface quality of the product.Through metallographic microscopy and scanning electr...Many spot defects were found on the surface of a cold-rolled Fe-36%Ni alloy strip produced in a factory,which seriously affected the surface quality of the product.Through metallographic microscopy and scanning electron microscopy analyses,it was found that the spot defects were caused by the residual oxide layer on the surface of the cold-rolled Fe-36%Ni alloy strip after hydrogen annealing.By properly increasing the grinding amount of the blank before cold rolling to remove the oxide layer,the spot defects on the surface of the cold-rolled strip were effectively eliminated,and the surface quality of the product was ensured.展开更多
An internal defect meter is an instrument to detect the internal inclusion defects of cold-rolled strip steel.The detection accuracy of the equipment can be evaluated based on the similarity of the multiple detection ...An internal defect meter is an instrument to detect the internal inclusion defects of cold-rolled strip steel.The detection accuracy of the equipment can be evaluated based on the similarity of the multiple detection data obtained for the same steel coil.Based on the cosine similarity model and eigenvalue matrix model,a comprehensive evaluation method to calculate the weighted average of similarity is proposed.Results show that the new method is consistent with and can even replace artificial evaluation to realize the automatic evaluation of strip defect detection results.展开更多
Composting as a solution to the increasing generation of municipal solid waste (MSW), also contribute to GHGs emission when not controlled and could lack some basic nutrients, especially nitrogen. This study assessed ...Composting as a solution to the increasing generation of municipal solid waste (MSW), also contribute to GHGs emission when not controlled and could lack some basic nutrients, especially nitrogen. This study assessed the split-additions of nitrogen-rich substrate to composting materials and their effect on GHGs emissions as well as the quality of the composts. Nitrogen-rich substrates formulated from pig and goat manure were co-composted with MSW for a 12-weeks period by split adding at mesophilic (˚C) and thermophilic (>50˚C) stages in five different treatments. Representative samples from the compost were taken from each treatment for physicochemical, heavy metals and bacteriological analysis. In-situ CH<sub>4</sub>, CO<sub>2</sub>, N<sub>2</sub>O gas emissions were also analyzed weekly during composting. It was observed that all the treatments showed significant organic matter decomposition, reaching thermophilic temperatures in the first week of composting. The absence affects the suitable agronomic properties. All nitrogen-rich substrate applied at thermophilic stage (Treatment two) recorded the highest N, P and K concentrations of 1.34%, 0.97% and 2.45%, respectively with highest nitrogen retention. In terms of GHG emissions, CO<sub>2</sub> was highest at the thermophilic stage when N-rich substrate was added in all treatment, while CH<sub>4</sub> was highest in the mesophilic stage with N-rich substrate addition. N<sub>2</sub>O showed no specific trend in the treatments. Split addition of the N-rich substrate for co-composting of MSW produced compost which is stable, has less nutrient loss and low GHG emissions. Split addition of a nitrogen-rich substrate could be an option for increasing the fertilizer value of MSW compost.展开更多
AIM To study the effect of cholecystokinin-octapeptide(CCK-8)and secretin on contractileactivity of isolated gastric muscle strips inguinea pigs.METHODS Each isolated gastric muscle stripwas suspended in a tissue ch...AIM To study the effect of cholecystokinin-octapeptide(CCK-8)and secretin on contractileactivity of isolated gastric muscle strips inguinea pigs.METHODS Each isolated gastric muscle stripwas suspended in a tissue chamber containing5 mL Krebs solution constantly warmed by waterjacked at 37℃ and supplied with a mixed gas of95% O<sub>2</sub> and 5% CO<sub>2</sub> After incubating for lhunder 1 g tension,varied concentrations of CCK-8 and secretin were added respectively in thetissue chamber and the contractile response wasmeasured isometrically on ink-writing recorders.RESULTS CCK-8 could increase①all regionalcircular and longitudinal muscular tension at rest(fundus LM 19.7%±2.1%,P【0.01;fundus CM16.7%±2.2%,P【0.01;gastric body LM 16.8%±2.3%,P【0.01;body CM 12.7%±2.6%,P【0.01;antrum LM 12.3%±1.3%,P【0.01;antrum CM 16.7%±4.5%,P【0.01;pylous CM12.7%±5.0%,P【0.05);②contractilefrequencies of body LM,both LM and CM ofantrum and pylorus CM(5.1/min±0.2/min to5.6/min±0.2/min,5.9/min±0.2/min to 6.6/min±0.l/min,5.4/min±0.3/min to 6.3/min±0.4/rain,1.3/min±0.2/min to 2.3/min±0.3/min,respectively,P【0.05);③the mean contractileamplitude of antral circular muscle(58.6%±18.4%,P【0.05)and ④the motility index ofpylorus CM(145.0%±23.8%,P【0.01),butdecrease the mean contractile amplitude ofgastric body and antral LM(-10.3%±3.3%,-10.5%±4.6%,respectively,P【0.05).All the CCK-8 effects were not blocked by atropine orindomethacin.Secretin had no effect on gastricsmooth muscle activity.CONCLUSION CCK-8 possessed bothexcitatory and inhibitory action on contractileactivity of different regions of stomach in guineapigs.Its action was not mediated via cholinergicM receptor and endogenous prostagiandinreceptor,展开更多
Various kinds of base oils were applied to cold rolling aluminum strips on a test mill for evaluationof the influences of these base oils,aromatics contents and viscosity of base oils on their lubricating performances...Various kinds of base oils were applied to cold rolling aluminum strips on a test mill for evaluationof the influences of these base oils,aromatics contents and viscosity of base oils on their lubricating performances and surface reflectivity of rolled strips at annealing. Results showed that low friction coefficient androlling force were obtained by using the normal paraffins,whereas their contaminations on the annealed stripsurface were the same as those of other saturated hydrocarbons. Aromatics in base oil affected the stir face reflectivity of annealed strips, but the decrease of aromatics in base oil was ineffective to improve rolled stripssurface quality when it is less than 1 %. Base oil viscosity has the great influences on the lubricating performances and surface reflectivity of annealed strips just in this condition.展开更多
Two experiments were carried out on the same compact strip production (CSP) line, which differs in that one of them experienced γ→α→γ thermal history. The differences in microstructure, precipitation, misorientat...Two experiments were carried out on the same compact strip production (CSP) line, which differs in that one of them experienced γ→α→γ thermal history. The differences in microstructure, precipitation, misorientation etc between two experiments were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD) and positron annihilation technique (PAT). The carbon concentration in matrix is more inhomogeneous in the experiment than that with γ→α→γ7 thermal history. The specific precipitation characteristic in the experiment without γ→α→γ thermal history is discussed on the basis of different carbon diffusion behavior and interaction between dislocation and excess carbon.展开更多
No matter what the flatness of a strip is, flat or defective, at an annealing furnace entrance, the strip can not keep its original shape and a remarkable change of its shape can be seen at the annealing furnace exit....No matter what the flatness of a strip is, flat or defective, at an annealing furnace entrance, the strip can not keep its original shape and a remarkable change of its shape can be seen at the annealing furnace exit. By investigating this phenomenon at the 2030 mm continuous annealing line which belonged to Baosteel, a finite element model of thermo-mechanical buckling deformation of strips in a continuous annealing furnace were established, and the mechanism of flatness changing and the contributing factors were researched by the finite element software ANSYS.展开更多
In the present paper, low carbon steel strips with different phosphorus contents were produced using a twin roll strip casting process. The solidification structure was studied and its features were analyzed in detail...In the present paper, low carbon steel strips with different phosphorus contents were produced using a twin roll strip casting process. The solidification structure was studied and its features were analyzed in detail. It was found that the strips possessed a fine microstructure compared with the mould cast steels. With increasing phosphorus content more ferrite has been formed with finer grains.展开更多
Thermomechanical experiments were carried out to reproduce the hot stamping process and to investigate the effects of process parameters on the microstructure and mechanical properties of stamped parts. The process pa...Thermomechanical experiments were carried out to reproduce the hot stamping process and to investigate the effects of process parameters on the microstructure and mechanical properties of stamped parts. The process parameters, such as austenitizing temperature, soaking time, initial deformation temperature and cooling rate, are studied. The resulting microstructures of specimens were observed and analyzed. To evaluate the mechanical properties of specimens, tensile and hardness tests were also performed at room temperature. The op-timum parameters to achieve the highest tensile strength and the desired microstructure were acquired by comparing and analyzing the results. It is indicated that hot deformation changes the transformation characteristics of 22MnB5 steel. Austenite deformation promotes the austen-ite-to-ferrite transformation and elevates the critical cooling rate to induce a fully martensitic transformation.展开更多
The influences of solidification rate on the microstructures of cast strips and corresponding sintered NdFeB magnets were investigated. The experimental results show that the volume fraction and size of columnar grain...The influences of solidification rate on the microstructures of cast strips and corresponding sintered NdFeB magnets were investigated. The experimental results show that the volume fraction and size of columnar grains vary with the wheel speed V, and the fraction is highest to more than 90% with 3.5μm in average width at V = 2m·s-1. The reasons for the improved magnetic performance were discussed based on the micromagnetic theory and microstructure analyses of the strips and sintered magnets. The magnetic properties of sintered NdFeB magnets made from the (Nd,Dy)13.0(Fe,Ga, Al)80.5B6.5 cast strip which was obtained at V = 2 m·s-1 are as follows: Br = 1.15 T( 11.25 kG), iHc = 2799 kA·m-1 (35.2 kOe) and (BH)max = 242 kJ·m-3(30.35 MGOe).展开更多
基金supported by the Scientific and Innovative Action Plan of Shanghai(21N31900800)Shanghai Rising-Star Program(23QB1403500)+4 种基金the Shanghai Sailing Program(20YF1443000)Shanghai Science and Technology Commission,the Belt and Road Project(20310750500)Talent Project of SAAS(2023-2025)Runup Plan of SAAS(ZP22211)the SAAS Program for Excellent Research Team(2022(B-16))。
文摘Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSPS and Cry1Ab/Ac was proposed and combined with a lateral flow immunochromatographic assay,named“Dual-RPA-LFD”,to visualize the dual detection of genetically modified(GM)crops.In which,the herbicide tolerance gene CP4-EPSPS and the insect resistance gene Cry1Ab/Ac were selected as targets taking into account the current status of the most widespread application of insect resistance and herbicide tolerance traits and their stacked traits.Gradient diluted plasmids,transgenic standards,and actual samples were used as templates to conduct sensitivity,specificity,and practicality assays,respectively.The constructed method achieved the visual detection of plasmid at levels as low as 100 copies,demonstrating its high sensitivity.In addition,good applicability to transgenic samples was observed,with no cross-interference between two test lines and no influence from other genes.In conclusion,this strategy achieved the expected purpose of simultaneous detection of the two popular targets in GM crops within 20 min at 37°C in a rapid,equipmentfree field manner,providing a new alternative for rapid screening for transgenic assays in the field.
基金National Natural Science Foundation of China(Grant Nos.22075023,22205022,and 22235003)to provide fund for conducting experiments。
文摘From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.
基金supported by the National Natural Science Foundation of China(31971853)。
文摘The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,promoting conventional intercropping strategies in modern agriculture can prove challenging.The innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a solution.This system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable agriculture.In this article,we provide an overview of SMSI and explain how it differs from traditional intercropping.We also discuss the core principles that foster higher yields and the prospects for its future development.
基金supported from the National Natural Science Foundation of China(Nos.52204356,52274342,and 52130408)the Natural Science Foundation of Hunan Province,China(Nos.2023JJ40762 and 2021JJ40731)。
文摘The interfacial wettability and heat transfer behavior are crucial in the strip casting of high phosphorus-containing steel.A hightemperature simulation of strip casting was conducted using the droplet solidification technique with the aims to reveal the effects of phosphorus content on interfacial wettability,deposited film,and interfacial heat transfer behavior.Results showed that when the phosphorus content increased from 0.014wt%to 0.406wt%,the mushy zone enlarged,the complete solidification temperature delayed from1518.3 to 1459.4℃,the final contact angle decreased from 118.4°to 102.8°,indicating improved interfacial contact,and the maximum heat flux increased from 6.9 to 9.2 MW/m2.Increasing the phosphorus content from 0.081wt%to 0.406wt%also accelerated the film deposition rate from 1.57 to 1.73μm per test,resulting in a thickened naturally deposited film with increased thermal resistance that advanced the transition point of heat transfer from the fifth experiment to the third experiment.
基金Project supported by the National Key Research and Development Program of China (Grant No.2021YFB2012600)the Shanghai Aerospace Science and Technology Innovation Fund,China (Grant No.SAST-2022-102)。
文摘Counterfeiting of modern banknotes poses a significant challenge,prompting the use of various preventive measures.One such measure is the magnetic anti-counterfeiting strip.However,due to its inherent weak magnetic properties,visualizing its magnetic distribution has been a longstanding challenge.In this work,we introduce an innovative method by using a fiber optic diamond probe,a highly sensitive quantum sensor designed specifically for detecting extremely weak magnetic fields.We employ this probe to achieve high-resolution imaging of the magnetic fields associated with the RMB 50denomination anti-counterfeiting strip.Additionally,we conduct computer simulations by using COMSOL Multiphysics software to deduce the potential geometric characteristics and material composition of the magnetic region within the anti-counterfeiting strip.The findings and method presented in this study hold broader significance,extending the RMB 50 denomination to various denominations of the Chinese currency and other items that employ magnetic anti-counterfeiting strips.These advances have the potential to significantly improve and promote security measures in order to prevent the banknotes from being counterfeited.
文摘Many spot defects were found on the surface of a cold-rolled Fe-36%Ni alloy strip produced in a factory,which seriously affected the surface quality of the product.Through metallographic microscopy and scanning electron microscopy analyses,it was found that the spot defects were caused by the residual oxide layer on the surface of the cold-rolled Fe-36%Ni alloy strip after hydrogen annealing.By properly increasing the grinding amount of the blank before cold rolling to remove the oxide layer,the spot defects on the surface of the cold-rolled strip were effectively eliminated,and the surface quality of the product was ensured.
文摘An internal defect meter is an instrument to detect the internal inclusion defects of cold-rolled strip steel.The detection accuracy of the equipment can be evaluated based on the similarity of the multiple detection data obtained for the same steel coil.Based on the cosine similarity model and eigenvalue matrix model,a comprehensive evaluation method to calculate the weighted average of similarity is proposed.Results show that the new method is consistent with and can even replace artificial evaluation to realize the automatic evaluation of strip defect detection results.
文摘Composting as a solution to the increasing generation of municipal solid waste (MSW), also contribute to GHGs emission when not controlled and could lack some basic nutrients, especially nitrogen. This study assessed the split-additions of nitrogen-rich substrate to composting materials and their effect on GHGs emissions as well as the quality of the composts. Nitrogen-rich substrates formulated from pig and goat manure were co-composted with MSW for a 12-weeks period by split adding at mesophilic (˚C) and thermophilic (>50˚C) stages in five different treatments. Representative samples from the compost were taken from each treatment for physicochemical, heavy metals and bacteriological analysis. In-situ CH<sub>4</sub>, CO<sub>2</sub>, N<sub>2</sub>O gas emissions were also analyzed weekly during composting. It was observed that all the treatments showed significant organic matter decomposition, reaching thermophilic temperatures in the first week of composting. The absence affects the suitable agronomic properties. All nitrogen-rich substrate applied at thermophilic stage (Treatment two) recorded the highest N, P and K concentrations of 1.34%, 0.97% and 2.45%, respectively with highest nitrogen retention. In terms of GHG emissions, CO<sub>2</sub> was highest at the thermophilic stage when N-rich substrate was added in all treatment, while CH<sub>4</sub> was highest in the mesophilic stage with N-rich substrate addition. N<sub>2</sub>O showed no specific trend in the treatments. Split addition of the N-rich substrate for co-composting of MSW produced compost which is stable, has less nutrient loss and low GHG emissions. Split addition of a nitrogen-rich substrate could be an option for increasing the fertilizer value of MSW compost.
基金Supported by the National Natural Science Foundation of China under Grant No.60173039(国家自然科学基金)the Special Foundation of 985 Project of SUN YAT-SEN University of China (中山大学985工程专项资金)
基金the Natural Science Foundation of Gansu Province,No.ZR-94-085.
文摘AIM To study the effect of cholecystokinin-octapeptide(CCK-8)and secretin on contractileactivity of isolated gastric muscle strips inguinea pigs.METHODS Each isolated gastric muscle stripwas suspended in a tissue chamber containing5 mL Krebs solution constantly warmed by waterjacked at 37℃ and supplied with a mixed gas of95% O<sub>2</sub> and 5% CO<sub>2</sub> After incubating for lhunder 1 g tension,varied concentrations of CCK-8 and secretin were added respectively in thetissue chamber and the contractile response wasmeasured isometrically on ink-writing recorders.RESULTS CCK-8 could increase①all regionalcircular and longitudinal muscular tension at rest(fundus LM 19.7%±2.1%,P【0.01;fundus CM16.7%±2.2%,P【0.01;gastric body LM 16.8%±2.3%,P【0.01;body CM 12.7%±2.6%,P【0.01;antrum LM 12.3%±1.3%,P【0.01;antrum CM 16.7%±4.5%,P【0.01;pylous CM12.7%±5.0%,P【0.05);②contractilefrequencies of body LM,both LM and CM ofantrum and pylorus CM(5.1/min±0.2/min to5.6/min±0.2/min,5.9/min±0.2/min to 6.6/min±0.l/min,5.4/min±0.3/min to 6.3/min±0.4/rain,1.3/min±0.2/min to 2.3/min±0.3/min,respectively,P【0.05);③the mean contractileamplitude of antral circular muscle(58.6%±18.4%,P【0.05)and ④the motility index ofpylorus CM(145.0%±23.8%,P【0.01),butdecrease the mean contractile amplitude ofgastric body and antral LM(-10.3%±3.3%,-10.5%±4.6%,respectively,P【0.05).All the CCK-8 effects were not blocked by atropine orindomethacin.Secretin had no effect on gastricsmooth muscle activity.CONCLUSION CCK-8 possessed bothexcitatory and inhibitory action on contractileactivity of different regions of stomach in guineapigs.Its action was not mediated via cholinergicM receptor and endogenous prostagiandinreceptor,
文摘Various kinds of base oils were applied to cold rolling aluminum strips on a test mill for evaluationof the influences of these base oils,aromatics contents and viscosity of base oils on their lubricating performances and surface reflectivity of rolled strips at annealing. Results showed that low friction coefficient androlling force were obtained by using the normal paraffins,whereas their contaminations on the annealed stripsurface were the same as those of other saturated hydrocarbons. Aromatics in base oil affected the stir face reflectivity of annealed strips, but the decrease of aromatics in base oil was ineffective to improve rolled stripssurface quality when it is less than 1 %. Base oil viscosity has the great influences on the lubricating performances and surface reflectivity of annealed strips just in this condition.
基金Authors acknowledge the financial support from the National Natural Science Foundation of China(No.50334010).
文摘Two experiments were carried out on the same compact strip production (CSP) line, which differs in that one of them experienced γ→α→γ thermal history. The differences in microstructure, precipitation, misorientation etc between two experiments were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD) and positron annihilation technique (PAT). The carbon concentration in matrix is more inhomogeneous in the experiment than that with γ→α→γ7 thermal history. The specific precipitation characteristic in the experiment without γ→α→γ thermal history is discussed on the basis of different carbon diffusion behavior and interaction between dislocation and excess carbon.
基金This work was financially supported by the National Natural Science Foundation of China (No.50675021)
文摘No matter what the flatness of a strip is, flat or defective, at an annealing furnace entrance, the strip can not keep its original shape and a remarkable change of its shape can be seen at the annealing furnace exit. By investigating this phenomenon at the 2030 mm continuous annealing line which belonged to Baosteel, a finite element model of thermo-mechanical buckling deformation of strips in a continuous annealing furnace were established, and the mechanism of flatness changing and the contributing factors were researched by the finite element software ANSYS.
基金This work was supported by the Major State Basic Research Development Program of China(973 Program)under the contract number of 2004CB619108the National Natural Science Foundation of China(No.50574018)the NECT-04-0278 Project of the Ministry of Education of China.
文摘In the present paper, low carbon steel strips with different phosphorus contents were produced using a twin roll strip casting process. The solidification structure was studied and its features were analyzed in detail. It was found that the strips possessed a fine microstructure compared with the mould cast steels. With increasing phosphorus content more ferrite has been formed with finer grains.
基金financially supported by the Research Fund for the Doctoral Program of Higher Education,China(No.20120006110017)
文摘Thermomechanical experiments were carried out to reproduce the hot stamping process and to investigate the effects of process parameters on the microstructure and mechanical properties of stamped parts. The process parameters, such as austenitizing temperature, soaking time, initial deformation temperature and cooling rate, are studied. The resulting microstructures of specimens were observed and analyzed. To evaluate the mechanical properties of specimens, tensile and hardness tests were also performed at room temperature. The op-timum parameters to achieve the highest tensile strength and the desired microstructure were acquired by comparing and analyzing the results. It is indicated that hot deformation changes the transformation characteristics of 22MnB5 steel. Austenite deformation promotes the austen-ite-to-ferrite transformation and elevates the critical cooling rate to induce a fully martensitic transformation.
基金Project supported by RE Application Engineering of National Ten-Fifth Year Plan of China (2002BA315A-1)
文摘The influences of solidification rate on the microstructures of cast strips and corresponding sintered NdFeB magnets were investigated. The experimental results show that the volume fraction and size of columnar grains vary with the wheel speed V, and the fraction is highest to more than 90% with 3.5μm in average width at V = 2m·s-1. The reasons for the improved magnetic performance were discussed based on the micromagnetic theory and microstructure analyses of the strips and sintered magnets. The magnetic properties of sintered NdFeB magnets made from the (Nd,Dy)13.0(Fe,Ga, Al)80.5B6.5 cast strip which was obtained at V = 2 m·s-1 are as follows: Br = 1.15 T( 11.25 kG), iHc = 2799 kA·m-1 (35.2 kOe) and (BH)max = 242 kJ·m-3(30.35 MGOe).