OBJECTIVE To access the efficacy and safety of the double-ProGlide technique for the femoral vein access-site closure in cryoballoon ablation with uninterrupted oral anticoagulants(OAC),and its impact on the electroph...OBJECTIVE To access the efficacy and safety of the double-ProGlide technique for the femoral vein access-site closure in cryoballoon ablation with uninterrupted oral anticoagulants(OAC),and its impact on the electrophysiology laboratory time as well as hospital stay after the procedure in this observational study.METHODS Patients with atrial fibrillation undergoing cryoballoon ablation with uninterrupted OAC at Department of Cardiology,Beijing Anzhen Hospital,Capital Medical University,Beijing,China from May 2019 to May 2021 were enrolled in this study.From October 2020,double-ProGlide technique was consistently used for hemostasis(ProGlide group),and before that conventional manual compression was utilized(manual compression group).The occurrence of vascular and groin complications was accessed during the hospital stay and until the three-month follow-up.RESULTS A total of 140 participants(69.30%of male,mean age:59.21±10.29 years)were evaluated,70 participants being in each group.Immediate hemostasis was achieved in all the patients with ProGlide closure.No major vascular complications were found in the ProGlide group while two major vascular complications were occurred in the manual compression group.The incidence of any groin complication was obviously higher in subjects with manual compression than patients with ProGlide devices(15.71%vs.2.86%,P=0.009).In addition,compared with the manual compression group,the ProGlide group was associated with significantly shorter total time in the electrophysiology laboratory[112.0(93.3–128.8)min vs.123.5(107.3–158.3)min,P=0.006],time from sheath removal until venous site hemostasis[3.8(3.4–4.2)min vs.8.0(7.6–8.5)min,P<0.001],bed rest time[8.0(7.6–8.0)h vs.14.1(12.0–17.6)h,P<0.001]and hospital stay after the procedure[13.8(12.5–17.8)h vs.38.0(21.5–41.0)h,P<0.001].CONCLUSIONS Utilization of the double-ProGlide technique for hemostasis after cryoballoon ablation with uninterrupted OAC is feasible and safe,which has the clinical benefit in reducing the total electrophysiology laboratory time and the hospital stay length after the procedure.展开更多
BACKGROUND Comminuted manubrium sterni fractures are rare,and internal fixation methods are limited.This report explored a practical and feasible method of internal fixation for comminuted manubrium sterni fractures.C...BACKGROUND Comminuted manubrium sterni fractures are rare,and internal fixation methods are limited.This report explored a practical and feasible method of internal fixation for comminuted manubrium sterni fractures.CASE SUMMARY A 17-year-old female was injured in a car accident for which she underwent debridement and suturing of her head and anterior chest wounds in another hospital.Eight days later,the patient was transferred to our hospital for surgical treatment.The manubrium sterni was found intraoperatively to be split into three irregular fragments with obvious overlap and separation displacement.Meanwhile,a manubriosternal joint dislocation and left first rib cartilage fracture were observed.The retraction force of the shape-memory alloy staples was used to pull the fracture fragments together.Two more titanium locking plates were then used to fix the manubrium sterni and corpus sterni longitudinally,and the left first rib cartilage fracture was repositioned and fixed with a titanium locking plate.A postoperative computed tomography scan showed reduced and rigid fixation of the comminuted manubrium sterni fractures.The patient recovered well with no significant complaints of discomfort.The patient was discharged 10 days postoperatively after the stitches had been removed.CONCLUSION Shape-memory alloy staples had the advantage of being safe and effective during the repositioning and internal fixation of comminuted manubrium sterni fractures.Therefore,they provided a new surgical option for comminuted manubrium sterni fractures.展开更多
Background Obstructive sleep apnea （OSA） is a common disease in patients with acute coronary syndrome （ACS） and associated with an increased risk of fatal and nonfatal cardiovascular events. However, most patients...Background Obstructive sleep apnea （OSA） is a common disease in patients with acute coronary syndrome （ACS） and associated with an increased risk of fatal and nonfatal cardiovascular events. However, most patients in previous study were treated with bare metal stents and the sample sizes were relatively low. The goal of this study was to evaluate the influence of OSA on the severity and prognosis of patients admitted for ACS. Methods In this prospective cohort study, we enrolled patients with ACS who were hospitalized for coronary angiogram/percutaneous coronary intervention and undergone polysomnography. We divided the patients into two groups： moderate to severe OSA group [apnea-hypopnea index （AHI） 〉 15 events/h] and control group （AHI ≤ 15 events/h）. They were followed up for up 32 months. Then, we compared the ACS severity and long-term major adverse cardiovascular events （MACE） in patients with different severity of OSA. Results Five hundred and twenty nine patients were included in the final analysis, with 76% of them being men and an average age of 59 ＋ 10 years. The overall mean AHI is 29 ± 19 events/h, 70.5% of them （373/529） being with moderate to severe OSA and 29.5% （156/529） assign into control group. Compared with controls, patients with moderate or severe OSA exhibited a higher prevalence of hypertension as well as higher body mass index, SYNTAX score, Epworth score and length of hospitalization. With a median follow-up duration of 30 months, accumulative rate of MACE was also higher in patients with moderate or severe OSA than that in the control group （8.6% vs. 3.2%, P = 0.028）. After adjusting for baseline confounders by cox regression model, moderate to severe OSA was an independent risk factor of long-term MACE （P = 0.047, HR = 1.618, 95% CI： 1.069-3.869）. Conclusions The results of this study demonstrate that moderate or severe OSA is correlated with disease severity and associated with worse long-term prognosis in ACS patients. The results raising the possibility that early diagnose and interventions of OSA could improve long-term outcomes in ACS patients.展开更多
Background Transradial coronary procedure （TRP） traumatizes the radial artery （RA）, especially resulting in changes to arterial wall morphology. This study explored the significance of the early onset of traumatic...Background Transradial coronary procedure （TRP） traumatizes the radial artery （RA）, especially resulting in changes to arterial wall morphology. This study explored the significance of the early onset of traumatic effects to wall layers of the RA following the first TRP （FTRP） and repeat TRP （RTRP） using very-high-frequency ultrabiomicroscopy （VHFUBM）. Methods A total of 1431 patients that re- ceived TRP were divided into the FTRP group that comprised 781 patients and the RTRP group that comprised 650 patients depending on the number of procedures. Two-dimensional RA images were acquired by 30-55 MHz ultrasound one day before and one day after the pro- cedure. Results After TRP, the incidence of intimal tears, medial dissections and external elastic lamina fracture were greater in the RTRP （P 〈 0.001）. The RTRP group showed significantly thicker intimal thickness （IT）, media thickness （MT）, adventitia thickness and all complex layer thicknesses as compared with the FTRP group （P 〈 0.001）. Conclusions Multivariate linear regression analysis discovered that repeated TRP and other observations were independent predictors of increased IT in post-operative RA. VHFUBM provides an approach to study structural and histopathological injury in the wall layers of RA which showed increased trauma to the RA following RTRP.展开更多
Objective To evaluate the effects and mechanisms of glucose-insulin-potassium(GIK)on post-procedural myocardial injury(PMI)after percutaneous coronary intervention(PCI).Methods A total of 200 non-diabetic patients wit...Objective To evaluate the effects and mechanisms of glucose-insulin-potassium(GIK)on post-procedural myocardial injury(PMI)after percutaneous coronary intervention(PCI).Methods A total of 200 non-diabetic patients with documented coronary heart disease(CHD)were divided into the Group GIK and Group G,with 100 patients in each group.Patients in Group G were given intravenous infusion of glucose solution 2 hours before PCI.As compared,patients in Group GIK were given GIK.Results Both post-procedural creatine phosphokinase isoenzyme MB(CK-MB;62.1±47.8 vs.48.8±52.6 U/L,P=0.007)and cTnI(0.68±0.83 vs.0.19±0.24 ng/mL,P<0.001)in Group GIK were significantly higher than those in Group G.In Group G,9.0%and 4.0%of patients had post-procedural increases in CK-MB 1-3 times and>3 times,which were significantly lower than those in Group GIK(14.0%and 7.0%,respectively;all P values<0.01);13.0%and 7.0%of patients had post-procedural increases in cTnI 1-3 times and>3 times,which were also significantly lower than those in Group GIK(21.0%and 13.0%,respectively;all P<0.001).Pre-procedural(10.2±4.5 vs.5.1±6.3,P<0.001)and post-procedural rapid blood glucose(RBG)levels(8.9±3.9 vs.5.3±5.6,P<0.001)in Group G were higher than those in Group GIK.In adjusted logistic models,usage of GIK(compared with glucose solution)remained significantly and independently associated with higher risk of post-procedural increases in both CK-MB and cTnI levels>3 times.Furthermore,pre-procedural RBG levels<5.0mmol/L were significantly associated with higher risk of post-procedural increases in both CK-MB and cTnI levels.Conclusions In non-diabetic patients with CHD,the administration of GIK may increase the risk of PMI due to hypoglycemia induced by GIK.展开更多
The approximately equimolar ratio A1CrNiSiTi multi-principal element alloy （MPEA） coatings were fab- ricated by laser cladding on Ti-6Al-4V （Ti64） alloy. Scanning electron microscopy （SEM）, equipped with an ener...The approximately equimolar ratio A1CrNiSiTi multi-principal element alloy （MPEA） coatings were fab- ricated by laser cladding on Ti-6Al-4V （Ti64） alloy. Scanning electron microscopy （SEM）, equipped with an energy-dispersive spectroscopy （EDS）, and X-ray diffrac- tion （XRD） were used to characterize the microstructure and composition. Investigations show that the coatings consist of （Ti, Cr）5Si3 and NiA1 phases, formed by in situ reaction. The phase composition is initially explicated according to obtainable binary and ternary phase diagrams, and the formation Gibbs energy of TisSi3, VsSi3 and CrsSi3. Dry sliding reciprocating friction and wear tests of the A1CrNiSiTi coating and Ti64 alloy substrate without coating were evaluated. A surface mapping profiler was used to evaluate the wear volume. The worn surface was characterized by SEM-EDS. The hardness and wear resistance of the A1CrNiSiTi coating are well compared with that of the basal material （Ti64）. The main wear mechanism of the AICrNiSiTi coating is slightly adhesive transfer from GCrl5 counterpart, and a mixed layer com- posed of transferred materials and oxide is formed.展开更多
The effects of ausforming procedure and subsequent annealing treatments on microstructures of cobalt（Co）samples are investigated by electron channeling contrast and electron backscatter diffraction techniques.Result...The effects of ausforming procedure and subsequent annealing treatments on microstructures of cobalt（Co）samples are investigated by electron channeling contrast and electron backscatter diffraction techniques.Results show that the ausformed Co samples consist of coarsen blocky laths（single ε phase）with the irregular morphology and the ultra-fine acicular laths（dual phase：γ and ε）with the slender and rectangular morphologies.As compared to the slight reduction sample,the much denser acicular laths are observed in the heavily ausformed sample.In addition,recrystallization behavior and annealing-induced 7--＋ e transformation have occurred in ausformed Co samples during the annealing treatment.展开更多
Spherical polyelectrolyte brushes （SPBs） consisting of polystyrene （PS） core and poly（2-aminoethyl methacrylate hydrochloride） （PAEMH） shell were prepared by photo-emulsion polymerization. Au nanoparticles （A...Spherical polyelectrolyte brushes （SPBs） consisting of polystyrene （PS） core and poly（2-aminoethyl methacrylate hydrochloride） （PAEMH） shell were prepared by photo-emulsion polymerization. Au nanoparticles （Au-NPs） with controlled size and size distribution were synthesized in situ using SPBs as nanoreactors. Via layer-by-layer deposition technique on the surface of SPBs, nano-composite particles with Au/Ag-NPs bilayer and Au/Ag/Au-NPs trilayer were prepared. The structures of the as-prepared Au/Ag multilayer SPBs were characterized by UV-Vis spectroscopy, TEM, ICP-AES and DLS. The charge reversal of the nano-composite particles observed by zeta potential confirmed the success of layer-by-layer assembly. The Au/Ag-NPs bilayer nano-composite particles showed high catalytic efficiency with an apparent activation energy of about 41.2 kJ/mol in the reduction reaction of 4-nitrophenol to 4-aminophenol in the existence of sodium borohydride monitored. The catalytic activity ofAu/Ag-NPs multilayer SPBs close to that of Au-NPs SPBs and much higher than that of Ag-NPs SPBs reveals its potential applications in cost-effective catalysts with high-performance.展开更多
Advanced characterization techniques are utilized to investigate the effect of laser surface treatment on microstructural evolution of pure titanium（Ti）.The results show that there are three distinctly different typ...Advanced characterization techniques are utilized to investigate the effect of laser surface treatment on microstructural evolution of pure titanium（Ti）.The results show that there are three distinctly different types of microstructure from surface to substrate in Ti samples,including phase transformation and solidification microstructure in zone I（melting zone）;insufficient recrystallization grains with residual a martensitic plates in zone II（heat-affected zone,HAZ）;fully recrystallization microstructure in zone III（base metal,BM）.The hardness evolution profiles under different laser treatment parameters are similar.The highest hardness in MZ is ascribed to α plate,while the lowest hardness value in HAZ is due to the insufficiently recrystallized grains.The metallurgical process on the laser-modified Ti samples is systematically discussed in this work.展开更多
基金supported by the National Natural Science Foundation of China(No.81100143)the Beijing Nova Program(Z121107002512053)+4 种基金the Beijing Health System High Level Health Technology Talent Cultivation Plan(No.2013-3-013)the Beijing Outstanding Talent Training Program(No.2014000021223ZK32)the Beijing National Science Foundation(No.7212100)the Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support(ZYLX201303)the National Key Clinical Speciality Construction Project。
文摘OBJECTIVE To access the efficacy and safety of the double-ProGlide technique for the femoral vein access-site closure in cryoballoon ablation with uninterrupted oral anticoagulants(OAC),and its impact on the electrophysiology laboratory time as well as hospital stay after the procedure in this observational study.METHODS Patients with atrial fibrillation undergoing cryoballoon ablation with uninterrupted OAC at Department of Cardiology,Beijing Anzhen Hospital,Capital Medical University,Beijing,China from May 2019 to May 2021 were enrolled in this study.From October 2020,double-ProGlide technique was consistently used for hemostasis(ProGlide group),and before that conventional manual compression was utilized(manual compression group).The occurrence of vascular and groin complications was accessed during the hospital stay and until the three-month follow-up.RESULTS A total of 140 participants(69.30%of male,mean age:59.21±10.29 years)were evaluated,70 participants being in each group.Immediate hemostasis was achieved in all the patients with ProGlide closure.No major vascular complications were found in the ProGlide group while two major vascular complications were occurred in the manual compression group.The incidence of any groin complication was obviously higher in subjects with manual compression than patients with ProGlide devices(15.71%vs.2.86%,P=0.009).In addition,compared with the manual compression group,the ProGlide group was associated with significantly shorter total time in the electrophysiology laboratory[112.0(93.3–128.8)min vs.123.5(107.3–158.3)min,P=0.006],time from sheath removal until venous site hemostasis[3.8(3.4–4.2)min vs.8.0(7.6–8.5)min,P<0.001],bed rest time[8.0(7.6–8.0)h vs.14.1(12.0–17.6)h,P<0.001]and hospital stay after the procedure[13.8(12.5–17.8)h vs.38.0(21.5–41.0)h,P<0.001].CONCLUSIONS Utilization of the double-ProGlide technique for hemostasis after cryoballoon ablation with uninterrupted OAC is feasible and safe,which has the clinical benefit in reducing the total electrophysiology laboratory time and the hospital stay length after the procedure.
基金Supported by Shenyang Medical College Youth Scientific Research Fund,No.20202027.
文摘BACKGROUND Comminuted manubrium sterni fractures are rare,and internal fixation methods are limited.This report explored a practical and feasible method of internal fixation for comminuted manubrium sterni fractures.CASE SUMMARY A 17-year-old female was injured in a car accident for which she underwent debridement and suturing of her head and anterior chest wounds in another hospital.Eight days later,the patient was transferred to our hospital for surgical treatment.The manubrium sterni was found intraoperatively to be split into three irregular fragments with obvious overlap and separation displacement.Meanwhile,a manubriosternal joint dislocation and left first rib cartilage fracture were observed.The retraction force of the shape-memory alloy staples was used to pull the fracture fragments together.Two more titanium locking plates were then used to fix the manubrium sterni and corpus sterni longitudinally,and the left first rib cartilage fracture was repositioned and fixed with a titanium locking plate.A postoperative computed tomography scan showed reduced and rigid fixation of the comminuted manubrium sterni fractures.The patient recovered well with no significant complaints of discomfort.The patient was discharged 10 days postoperatively after the stitches had been removed.CONCLUSION Shape-memory alloy staples had the advantage of being safe and effective during the repositioning and internal fixation of comminuted manubrium sterni fractures.Therefore,they provided a new surgical option for comminuted manubrium sterni fractures.
文摘Background Obstructive sleep apnea （OSA） is a common disease in patients with acute coronary syndrome （ACS） and associated with an increased risk of fatal and nonfatal cardiovascular events. However, most patients in previous study were treated with bare metal stents and the sample sizes were relatively low. The goal of this study was to evaluate the influence of OSA on the severity and prognosis of patients admitted for ACS. Methods In this prospective cohort study, we enrolled patients with ACS who were hospitalized for coronary angiogram/percutaneous coronary intervention and undergone polysomnography. We divided the patients into two groups： moderate to severe OSA group [apnea-hypopnea index （AHI） 〉 15 events/h] and control group （AHI ≤ 15 events/h）. They were followed up for up 32 months. Then, we compared the ACS severity and long-term major adverse cardiovascular events （MACE） in patients with different severity of OSA. Results Five hundred and twenty nine patients were included in the final analysis, with 76% of them being men and an average age of 59 ＋ 10 years. The overall mean AHI is 29 ± 19 events/h, 70.5% of them （373/529） being with moderate to severe OSA and 29.5% （156/529） assign into control group. Compared with controls, patients with moderate or severe OSA exhibited a higher prevalence of hypertension as well as higher body mass index, SYNTAX score, Epworth score and length of hospitalization. With a median follow-up duration of 30 months, accumulative rate of MACE was also higher in patients with moderate or severe OSA than that in the control group （8.6% vs. 3.2%, P = 0.028）. After adjusting for baseline confounders by cox regression model, moderate to severe OSA was an independent risk factor of long-term MACE （P = 0.047, HR = 1.618, 95% CI： 1.069-3.869）. Conclusions The results of this study demonstrate that moderate or severe OSA is correlated with disease severity and associated with worse long-term prognosis in ACS patients. The results raising the possibility that early diagnose and interventions of OSA could improve long-term outcomes in ACS patients.
文摘Background Transradial coronary procedure （TRP） traumatizes the radial artery （RA）, especially resulting in changes to arterial wall morphology. This study explored the significance of the early onset of traumatic effects to wall layers of the RA following the first TRP （FTRP） and repeat TRP （RTRP） using very-high-frequency ultrabiomicroscopy （VHFUBM）. Methods A total of 1431 patients that re- ceived TRP were divided into the FTRP group that comprised 781 patients and the RTRP group that comprised 650 patients depending on the number of procedures. Two-dimensional RA images were acquired by 30-55 MHz ultrasound one day before and one day after the pro- cedure. Results After TRP, the incidence of intimal tears, medial dissections and external elastic lamina fracture were greater in the RTRP （P 〈 0.001）. The RTRP group showed significantly thicker intimal thickness （IT）, media thickness （MT）, adventitia thickness and all complex layer thicknesses as compared with the FTRP group （P 〈 0.001）. Conclusions Multivariate linear regression analysis discovered that repeated TRP and other observations were independent predictors of increased IT in post-operative RA. VHFUBM provides an approach to study structural and histopathological injury in the wall layers of RA which showed increased trauma to the RA following RTRP.
基金The report was supported by grants from the Beijing Nova Program(No.Z121107002512053)the Beijing Health System High Level Health Technology Talent Cultivation Plan(No.2013-3-013)+3 种基金Beijing Outstanding Talent Training Program(No.2014000021223ZK32)the National Natural Science Foundation of China(No.81100143)the Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support(No.ZYLX 201303)and the National Key Clinical Speciality Construction Project.
文摘Objective To evaluate the effects and mechanisms of glucose-insulin-potassium(GIK)on post-procedural myocardial injury(PMI)after percutaneous coronary intervention(PCI).Methods A total of 200 non-diabetic patients with documented coronary heart disease(CHD)were divided into the Group GIK and Group G,with 100 patients in each group.Patients in Group G were given intravenous infusion of glucose solution 2 hours before PCI.As compared,patients in Group GIK were given GIK.Results Both post-procedural creatine phosphokinase isoenzyme MB(CK-MB;62.1±47.8 vs.48.8±52.6 U/L,P=0.007)and cTnI(0.68±0.83 vs.0.19±0.24 ng/mL,P<0.001)in Group GIK were significantly higher than those in Group G.In Group G,9.0%and 4.0%of patients had post-procedural increases in CK-MB 1-3 times and>3 times,which were significantly lower than those in Group GIK(14.0%and 7.0%,respectively;all P values<0.01);13.0%and 7.0%of patients had post-procedural increases in cTnI 1-3 times and>3 times,which were also significantly lower than those in Group GIK(21.0%and 13.0%,respectively;all P<0.001).Pre-procedural(10.2±4.5 vs.5.1±6.3,P<0.001)and post-procedural rapid blood glucose(RBG)levels(8.9±3.9 vs.5.3±5.6,P<0.001)in Group G were higher than those in Group GIK.In adjusted logistic models,usage of GIK(compared with glucose solution)remained significantly and independently associated with higher risk of post-procedural increases in both CK-MB and cTnI levels>3 times.Furthermore,pre-procedural RBG levels<5.0mmol/L were significantly associated with higher risk of post-procedural increases in both CK-MB and cTnI levels.Conclusions In non-diabetic patients with CHD,the administration of GIK may increase the risk of PMI due to hypoglycemia induced by GIK.
基金supported by the Chongqing Research Program of Basic Research and Frontier Technology(No.CSTC2013jcyjA50016)the National Natural Science Foundation of China(Nos.51401039,51571037 and 51204110)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(No.KJ1709204).
文摘The approximately equimolar ratio A1CrNiSiTi multi-principal element alloy （MPEA） coatings were fab- ricated by laser cladding on Ti-6Al-4V （Ti64） alloy. Scanning electron microscopy （SEM）, equipped with an energy-dispersive spectroscopy （EDS）, and X-ray diffrac- tion （XRD） were used to characterize the microstructure and composition. Investigations show that the coatings consist of （Ti, Cr）5Si3 and NiA1 phases, formed by in situ reaction. The phase composition is initially explicated according to obtainable binary and ternary phase diagrams, and the formation Gibbs energy of TisSi3, VsSi3 and CrsSi3. Dry sliding reciprocating friction and wear tests of the A1CrNiSiTi coating and Ti64 alloy substrate without coating were evaluated. A surface mapping profiler was used to evaluate the wear volume. The worn surface was characterized by SEM-EDS. The hardness and wear resistance of the A1CrNiSiTi coating are well compared with that of the basal material （Ti64）. The main wear mechanism of the AICrNiSiTi coating is slightly adhesive transfer from GCrl5 counterpart, and a mixed layer com- posed of transferred materials and oxide is formed.
基金supported by the National Natural Science Foundation of China(Nos.51501026 and 51401039)the Natural Science Foundation of Chongqing(CSTC2014jcyj A50017)+1 种基金the Scientific and Technological Research Program of Chongqing Municipal Education Commission(No.KJ1500923)the Australian Research Council
文摘The effects of ausforming procedure and subsequent annealing treatments on microstructures of cobalt（Co）samples are investigated by electron channeling contrast and electron backscatter diffraction techniques.Results show that the ausformed Co samples consist of coarsen blocky laths（single ε phase）with the irregular morphology and the ultra-fine acicular laths（dual phase：γ and ε）with the slender and rectangular morphologies.As compared to the slight reduction sample,the much denser acicular laths are observed in the heavily ausformed sample.In addition,recrystallization behavior and annealing-induced 7--＋ e transformation have occurred in ausformed Co samples during the annealing treatment.
基金financially supported by the National Natural Science Foundation of China(No.51273063 and 51003028)the Fundamental Research Funds for the Central Universities+1 种基金the Higher School Specialized Research Fund for the Doctoral Program(No.20110074110003)111 Project Grant(No.B08021)
文摘Spherical polyelectrolyte brushes （SPBs） consisting of polystyrene （PS） core and poly（2-aminoethyl methacrylate hydrochloride） （PAEMH） shell were prepared by photo-emulsion polymerization. Au nanoparticles （Au-NPs） with controlled size and size distribution were synthesized in situ using SPBs as nanoreactors. Via layer-by-layer deposition technique on the surface of SPBs, nano-composite particles with Au/Ag-NPs bilayer and Au/Ag/Au-NPs trilayer were prepared. The structures of the as-prepared Au/Ag multilayer SPBs were characterized by UV-Vis spectroscopy, TEM, ICP-AES and DLS. The charge reversal of the nano-composite particles observed by zeta potential confirmed the success of layer-by-layer assembly. The Au/Ag-NPs bilayer nano-composite particles showed high catalytic efficiency with an apparent activation energy of about 41.2 kJ/mol in the reduction reaction of 4-nitrophenol to 4-aminophenol in the existence of sodium borohydride monitored. The catalytic activity ofAu/Ag-NPs multilayer SPBs close to that of Au-NPs SPBs and much higher than that of Ag-NPs SPBs reveals its potential applications in cost-effective catalysts with high-performance.
基金supported by the National Natural Science Foundation of China (Nos. 51401039 and 51501026)the Natural Science Foundation of Chongqing (No. CSTC2014jcyj A50017)the Scientific and Technological Research Program of Chongqing Municipal Education Commission (Nos. KJ1500923 and KJ1709204)
文摘Advanced characterization techniques are utilized to investigate the effect of laser surface treatment on microstructural evolution of pure titanium（Ti）.The results show that there are three distinctly different types of microstructure from surface to substrate in Ti samples,including phase transformation and solidification microstructure in zone I（melting zone）;insufficient recrystallization grains with residual a martensitic plates in zone II（heat-affected zone,HAZ）;fully recrystallization microstructure in zone III（base metal,BM）.The hardness evolution profiles under different laser treatment parameters are similar.The highest hardness in MZ is ascribed to α plate,while the lowest hardness value in HAZ is due to the insufficiently recrystallized grains.The metallurgical process on the laser-modified Ti samples is systematically discussed in this work.
