Due to the insufficient slip systems in hexagonal close-packed structure,twinning is frequently activated to support stable plastic deformation of Mg alloy.In this work,we found four typical twin-like interfaces with ...Due to the insufficient slip systems in hexagonal close-packed structure,twinning is frequently activated to support stable plastic deformation of Mg alloy.In this work,we found four typical twin-like interfaces with misorientations of 102°,109°,142°and 149°,respectively,which had not only a shared[1120]zone axis of neighboring grains,but also overlapped diffraction spots similar to twins.However,highresolution transmission electron microscope(HRTEM)analysis revealed that the interfaces in real space deviated from the supposed twinning planes in reciprocal space,i.e.their overlapped diffraction spots.We clarified that the incoherent interfaces were co-axial grain boundaries(CGBs).Additionally,a special angle ofθ,close to 90°,between the interface and one side of basal plane,was frequently formed in CGBs.We proposed that interaction of multiple twinning contributes to the formation of CGBs,and theθis formed due to alternative tensile and compression twinning under a uniaxial loading.展开更多
Due to the insufficient slip systems,Mg and its alloys exhibit poor ductility during plastic deformation at room temperature.To solve this problem,alloying is considered as a most effective method to improve the ducti...Due to the insufficient slip systems,Mg and its alloys exhibit poor ductility during plastic deformation at room temperature.To solve this problem,alloying is considered as a most effective method to improve the ductility of Mg alloys,which attracts wide attentions of industries.However,it is still a challenge to understand the ductilization mechanism,because of the complicated alloying elements and their interactions with Mg matrix.In this work,pure Mg and Mg-Y alloys were comparatively studied to investigate the effect of Y addition on microstructure evolution and mechanical properties.A huge increase of uniform elongation,from 5.3%to 20.7%,was achieved via only 3 wt%addition of yttrium.TEM results revealed that the only activated slip system in pure Mg was basal<a>slip,led to its poor ductility at room temperature.In contrast,a large number of stacking faults and non-basal dislocations with<c>component were observed in the deformed Mg-Y alloy,which was proposed as the main reason for significant improvement of strain hardening and ductility.High resolution TEM indicated that most of the stacking faults were II and 12 intrinsic faults,which played a critical role in improving the ductility of Mg-Y alloy.Addition of Y into Mg alloy decreased the stacking fault energy,which induced high density stacking faults in the grain interior.展开更多
Rare earth(RE)can produce excellent precipitation hardening in Mg alloys.However,when forming a solid solution,it also deteriorates formability,a problem that can usually be overcome by raising deformation temperature...Rare earth(RE)can produce excellent precipitation hardening in Mg alloys.However,when forming a solid solution,it also deteriorates formability,a problem that can usually be overcome by raising deformation temperature.Here we report an unexpected observation of high temperature brittleness in a Mg-Gd-Y-Ag alloy.As the temperature reached 500℃,the formability decreased drastically,leading to severe intergranular fracture under only 0.5% strain.This was caused by failure of grain boundaries,which are weakened by segregated interfacial compounds.展开更多
White feather broilers in some broiler farm in Chengde area developed arthritis and died acutely. In order to identify the pathogen inducing the disease and death of the white feather broilers,samples such as livers a...White feather broilers in some broiler farm in Chengde area developed arthritis and died acutely. In order to identify the pathogen inducing the disease and death of the white feather broilers,samples such as livers and joint pus were collected from dead broilers under sterile condition,and one pathogenic strain was isolated. The isolate was identified to be Staphylococcus aureus through isolated culture,morphologic observation,inspection of biochemical property and animal test. The drug sensitivity test showed that the isolate was sensitive to ceftazidime,enrofloxacin,ceftriaxone,lincomycin and amikacin,but resistant to other drugs to different degrees.展开更多
[Objectives]The study aimed to identify the pathogenic E. coli strain that caused diarrhea in foxes and to analyze its drug sensitivity. [Methods]A pathogenic E. coli strain was isolated from dead foxes with diarrhea....[Objectives]The study aimed to identify the pathogenic E. coli strain that caused diarrhea in foxes and to analyze its drug sensitivity. [Methods]A pathogenic E. coli strain was isolated from dead foxes with diarrhea. By conventional bacterial isolation and culture,morphological observation,pathogenicity test and K-B disc method,the isolated strain was identified as pathogenic E. coli. [Results]The isolated pathogen was highly sensitive to ceftriaxone,cefotaxime,ciprofloxacin and lincomycin,moderately sensitive to enrofloxacin,neomycin,gentamycin,spectinomycin,florfenicol,amikacin and polymyxin,and resistant to ampicillin,amoxicillin and doxycycline. [Conclusions]This study provided reference for the prevention and control of diarrheal diseases in foxes in Qinhuangdao region.展开更多
[Objectives] The study aimed to identify the pathogen that causes diarrhea in minks. [Methods] Liver tissues were aseptically collected from dead minks with diarrhea. By bacterial isolation and culture,morphological o...[Objectives] The study aimed to identify the pathogen that causes diarrhea in minks. [Methods] Liver tissues were aseptically collected from dead minks with diarrhea. By bacterial isolation and culture,morphological observation,biochemical test and pathogenicity test,the isolated strain was identified as pathogenic E. coli. [Results]The pathogen causing diarrhea in minks was confirmed as a pathogenic E. coli strain. Drug sensitivity test indicated that the isolated pathogenic E. coli strain was highly sensitive to ceftazidime,cefotaxime,enrofloxacin,florfenicol and cephradine,moderately sensitive to ampicillin,ciprofloxacin,amikacin,doxycycline,lincomycin and gentamycin,and resistant to amoxycillin,neomycin,spectinomycin,polymyxin and penicillin. [Conclusions] This study provided reference for the prevention and control of abortion in female minks in Qinhuangdao region.展开更多
The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features.In this work,laminate dual-phase(DP)steels with high martensite content(laminate HMDP steels)were ...The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features.In this work,laminate dual-phase(DP)steels with high martensite content(laminate HMDP steels)were produced by a combination of warm rolling and intercritical annealing.Influence of rolling strain and annealing temperature on the microstructural evolution and mechanical properties of laminate HMDP steels were systematically studied.The strength of HMDP steels was significantly improved to~1.6 GPa associated with a high uniform elongation of 7%,as long as the laminate structure is maintained.The strengthening and ductilizing mechanisms of laminate HMDP steels are discussed based on the influence of laminate structure and the high martensite content,which promote the development of internal stresses and can be correlated to the Bauschinger effect as measured by the cyclic loadingunloading-reloading experiments.Detailed transmission electron microscopy(TEM)observation was applied to characterize the dislocation structure in the deformed ferrite.展开更多
Choroidal neovascularization(CNV)is a common pathological feature of various eye diseases and an important cause of visual impairment in middle-aged and elderly patients.In previous studies,tetrahedral framework nucle...Choroidal neovascularization(CNV)is a common pathological feature of various eye diseases and an important cause of visual impairment in middle-aged and elderly patients.In previous studies,tetrahedral framework nucleic acids(tFNAs)showed good carrier performance.In this experiment,we developed microRNA-155-equipped tFNAs(T-155)and explored its biological effects on CNV.Based on the results of in-vitro experiments,T-155 could regulate macrophages into the antiangiogenic M1 type.Then,we injected T-155 into the vitreous of laser-induced CNV model mice and found that T-155 significantly reduced the size and area of CNV,inhibited blood vessel leakage.In summary,we prove that T-155 could regulate the inflammatory process of CNV by polarizing macrophages,thereby improving the symptoms of CNV.Thus,T-155 might become a new DNA-based drug with great potential for treating CNV.展开更多
基金supported by the National Key R&D Program of China[grant number 2021YFA1200203]the Key Program of National Natural Science Foundation of China[grant number 51931003]+3 种基金the National Natural Science Foundation of China[grant numbers 52171118,52071178,51901103]the Projects in Science and Technique Plans of Ningbo City[grant number 2019B10083]the China Postdoctoral Science Foundation[grant number 2021M701715]the Opening Project of the Key Laboratory of Advanced Manufacturing and Intelligent Technology(Ministry of Education)of Harbin University of Science and Technology[grant number KFKT202103]
文摘Due to the insufficient slip systems in hexagonal close-packed structure,twinning is frequently activated to support stable plastic deformation of Mg alloy.In this work,we found four typical twin-like interfaces with misorientations of 102°,109°,142°and 149°,respectively,which had not only a shared[1120]zone axis of neighboring grains,but also overlapped diffraction spots similar to twins.However,highresolution transmission electron microscope(HRTEM)analysis revealed that the interfaces in real space deviated from the supposed twinning planes in reciprocal space,i.e.their overlapped diffraction spots.We clarified that the incoherent interfaces were co-axial grain boundaries(CGBs).Additionally,a special angle ofθ,close to 90°,between the interface and one side of basal plane,was frequently formed in CGBs.We proposed that interaction of multiple twinning contributes to the formation of CGBs,and theθis formed due to alternative tensile and compression twinning under a uniaxial loading.
基金the National Key R&D Program of China(2017YFA0204403)National Natural Science Foundation of China(51601003,51901103)the Fundamental Research Funds for the Central Universities(30918011342).
文摘Due to the insufficient slip systems,Mg and its alloys exhibit poor ductility during plastic deformation at room temperature.To solve this problem,alloying is considered as a most effective method to improve the ductility of Mg alloys,which attracts wide attentions of industries.However,it is still a challenge to understand the ductilization mechanism,because of the complicated alloying elements and their interactions with Mg matrix.In this work,pure Mg and Mg-Y alloys were comparatively studied to investigate the effect of Y addition on microstructure evolution and mechanical properties.A huge increase of uniform elongation,from 5.3%to 20.7%,was achieved via only 3 wt%addition of yttrium.TEM results revealed that the only activated slip system in pure Mg was basal<a>slip,led to its poor ductility at room temperature.In contrast,a large number of stacking faults and non-basal dislocations with<c>component were observed in the deformed Mg-Y alloy,which was proposed as the main reason for significant improvement of strain hardening and ductility.High resolution TEM indicated that most of the stacking faults were II and 12 intrinsic faults,which played a critical role in improving the ductility of Mg-Y alloy.Addition of Y into Mg alloy decreased the stacking fault energy,which induced high density stacking faults in the grain interior.
基金supported by National Natural Science Foundation of China(Grant numbers 52071178,51901103,51931003,51601003,51401172)the National Key Research and Development Program of China(Grant number 2017YFA0204403)Project of Natural Science Foundation of Heilongjiang Province(grant number LH2019E080)。
文摘Rare earth(RE)can produce excellent precipitation hardening in Mg alloys.However,when forming a solid solution,it also deteriorates formability,a problem that can usually be overcome by raising deformation temperature.Here we report an unexpected observation of high temperature brittleness in a Mg-Gd-Y-Ag alloy.As the temperature reached 500℃,the formability decreased drastically,leading to severe intergranular fracture under only 0.5% strain.This was caused by failure of grain boundaries,which are weakened by segregated interfacial compounds.
基金Supported by Hebei Science and Technology Deparment Project(17226607D)
文摘White feather broilers in some broiler farm in Chengde area developed arthritis and died acutely. In order to identify the pathogen inducing the disease and death of the white feather broilers,samples such as livers and joint pus were collected from dead broilers under sterile condition,and one pathogenic strain was isolated. The isolate was identified to be Staphylococcus aureus through isolated culture,morphologic observation,inspection of biochemical property and animal test. The drug sensitivity test showed that the isolate was sensitive to ceftazidime,enrofloxacin,ceftriaxone,lincomycin and amikacin,but resistant to other drugs to different degrees.
基金Supported by Project of Hebei Education Department(ZD2017234)Project of Science and Technology Bureau of Shijiazhuang(171500953A)Project of Science and Technology Bureau of Qinhuangdao(201602A046)
文摘[Objectives]The study aimed to identify the pathogenic E. coli strain that caused diarrhea in foxes and to analyze its drug sensitivity. [Methods]A pathogenic E. coli strain was isolated from dead foxes with diarrhea. By conventional bacterial isolation and culture,morphological observation,pathogenicity test and K-B disc method,the isolated strain was identified as pathogenic E. coli. [Results]The isolated pathogen was highly sensitive to ceftriaxone,cefotaxime,ciprofloxacin and lincomycin,moderately sensitive to enrofloxacin,neomycin,gentamycin,spectinomycin,florfenicol,amikacin and polymyxin,and resistant to ampicillin,amoxicillin and doxycycline. [Conclusions]This study provided reference for the prevention and control of diarrheal diseases in foxes in Qinhuangdao region.
基金Supported by Project of Hebei Education Department(ZD2017234)Project of Science and Technology Bureau of Shijiazhuang(171500953A)Project of Science and Technology Bureau of Qinhuangdao(201602A046)
文摘[Objectives] The study aimed to identify the pathogen that causes diarrhea in minks. [Methods] Liver tissues were aseptically collected from dead minks with diarrhea. By bacterial isolation and culture,morphological observation,biochemical test and pathogenicity test,the isolated strain was identified as pathogenic E. coli. [Results]The pathogen causing diarrhea in minks was confirmed as a pathogenic E. coli strain. Drug sensitivity test indicated that the isolated pathogenic E. coli strain was highly sensitive to ceftazidime,cefotaxime,enrofloxacin,florfenicol and cephradine,moderately sensitive to ampicillin,ciprofloxacin,amikacin,doxycycline,lincomycin and gentamycin,and resistant to amoxycillin,neomycin,spectinomycin,polymyxin and penicillin. [Conclusions] This study provided reference for the prevention and control of abortion in female minks in Qinhuangdao region.
基金supported financially by the National Key R&D Program of China(No.2017YFA0204403)the National Natural Science Foundation of China(Nos.51931003,51601094,51601003,51701097 and 51901103)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.30917011106 and 30918011342)the Natural Science Foundation of Jiangsu Province(Nos.BK20170843and BK20180492)。
文摘The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features.In this work,laminate dual-phase(DP)steels with high martensite content(laminate HMDP steels)were produced by a combination of warm rolling and intercritical annealing.Influence of rolling strain and annealing temperature on the microstructural evolution and mechanical properties of laminate HMDP steels were systematically studied.The strength of HMDP steels was significantly improved to~1.6 GPa associated with a high uniform elongation of 7%,as long as the laminate structure is maintained.The strengthening and ductilizing mechanisms of laminate HMDP steels are discussed based on the influence of laminate structure and the high martensite content,which promote the development of internal stresses and can be correlated to the Bauschinger effect as measured by the cyclic loadingunloading-reloading experiments.Detailed transmission electron microscopy(TEM)observation was applied to characterize the dislocation structure in the deformed ferrite.
基金supported by the National Key R&D Program of China(2019YFA0110600)National Natural Science Foundation of China(81970916,81671031)The National Major Scientific Equipment program(Grant No.2012YQ12008005).
文摘Choroidal neovascularization(CNV)is a common pathological feature of various eye diseases and an important cause of visual impairment in middle-aged and elderly patients.In previous studies,tetrahedral framework nucleic acids(tFNAs)showed good carrier performance.In this experiment,we developed microRNA-155-equipped tFNAs(T-155)and explored its biological effects on CNV.Based on the results of in-vitro experiments,T-155 could regulate macrophages into the antiangiogenic M1 type.Then,we injected T-155 into the vitreous of laser-induced CNV model mice and found that T-155 significantly reduced the size and area of CNV,inhibited blood vessel leakage.In summary,we prove that T-155 could regulate the inflammatory process of CNV by polarizing macrophages,thereby improving the symptoms of CNV.Thus,T-155 might become a new DNA-based drug with great potential for treating CNV.
