Zhen-Yu Liu - Academia.edu (original) (raw)
Papers by Zhen-Yu Liu
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases]
To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD... more To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD) with or without atherosclerosis (AS) and postmenopausal women with CAD. The clinical and coronary angiographic data, traditional risk factors (age, smoking, blood pressure, lipid profile, blood glucose, BMI, family history) were compared among premenopause (Pre-M, n=42) and post-menopause (Post-M, n=172) women with CAD as well as Pre-M patients with non-AS CAD (non-AS CAD, n=8). Compared with the Post-M patients with CAD, Pre-M CAD patients had significantly fewer traditional risk factors, such as hypertension, diabetes and hypercholesterolemia, significantly more acute coronary syndrome and fewer previous history of chest pain, significantly more single vessel lesion and lower Gessini score (all P < 0. 01). The logistic regression results showed that obesity is an independent risk factor for the development of CAD in premenopausal women (OR = 3. 655, 95% CI: 1. 5-11.59, P = 0.028). Hypertension (OR = 4.73, 95% CI: 0.991-22.589, P = 0.051) and hypercholesterolemia (OR = 4.68, 95% CI: 0.971-22.564, P = 0.055) might also contribute to the development of CAD in these patients. Clinical characteristics were similar between Pre-M and non-AS CAD patients (P > 0.05). Pre-M CAD patients had less traditional risk factors and lower coronary lesion score compared to post-M CAD patients. Obesity is an independent risk factor for Pre-M CAD. Non-AS coronary artery disease is also an important reason for the development of coronary arterial events in premenopausal women.
Acta Metallurgica Sinica -Chinese Edition-
Advanced Materials Research, 2011
Cailiao Gongcheng/Journal of Materials Engineering
Precipitation behaviors at ferrite phase zone for Nb bearing steel under ultra fast cooling condi... more Precipitation behaviors at ferrite phase zone for Nb bearing steel under ultra fast cooling conditions were investigated by using Gleeble-3800 thermomechanical simulator. Corresponding models were also obtained by considering solid solubility of Nb(C, N) and diffusion coefficient at ferrite phase zone. The results indicate that entering ultra fast cooling immediately and cooling to 650(ferrite phase zone) after rolling can restrain precipitation of Nb at austenite phase zone and realize precipitation at ferrite phase zone. Compared with precipitation behavior at austenite phase zone, the number of precipitates increases and sizes of precipitates are refined obviously at ferrite phase zone. The density of precipitates increases from 79 number·μm-2 to 373 number·μm2 and sizes of precipitates are refined from 12.9nm to 8.1nm. This can embody the effect of precipitation strengthening. The temperature of the maximum nucleation rate and the fastest precipitation are about 620 and 700 for ...
Key Engineering Materials, 2013
Materials Science Forum, 2013
Based on ultra fast cooling, effects of cooling paths on microstructure and mechanical properties... more Based on ultra fast cooling, effects of cooling paths on microstructure and mechanical properties of vanadium bearing microalloyed steel were investigated by the observation of optical microscope and scanning electron microscope and the testing of mechanical properties, moreover, the work-hardening exponent was determined based on stress-strain curves. The results show that using ultra fast cooling can effectively refine ferrite grain size and the ferrite grain size is decreased as the final temperature of ultra fast cooling is decreased. In addition, the microstructure and mechanical properties can be controlled by cooling paths. The ferrite-perlite microstructure with lower strength and higher n-value of approx. 0.2 and the ferrite-bainite microstructure with higher strength and lower n-value of approx. 0.16 can be gained at the higher and lower final temperature of ultra fast cooling, respectively. And the yield ratio are all lower than 0.85.
Materials Science Forum, 2012
ABSTRACT Thermo-mechanical Controlled Processing (TMCP) is one of the greatest achievements in st... more ABSTRACT Thermo-mechanical Controlled Processing (TMCP) is one of the greatest achievements in steel industry in the 20th century, which, however, depends too much upon low temperature rolling for the refinement of austenite grains, causing great loss in terms of productivity. To overcome this disadvantage, a new processing route with ultra fast cooling as the core has been proposed, and pilot rolling and industrial trials were carried out. As compared to conventional accelerated cooling, the ultra fast cooling can achieve cooling rate up to 300°C/s for 3 mm thick strip and highly homogeneous cooling by the pressurized water spraying. In the present work, the metallurgical backgrounds for ultra fast cooling in thermo-mechanical processing were studied and elucidated. By the pilot hot rolling experiments with a lean composition of a typical 600 MPa grade high strength steel, it has been found that the application of ultra fast cooling (UFC) at the exit of hot rolling mills can improve the strength by as much as 100 MPa as compared to the conventional TMCP. The strengthening mechanism lies in that the ultra fast cooling immediately after hot rolling may further improve the strengthening effects by precipitation, grain refinement, and dislocation hardening. The theoretical calculations and experiments indicate that the grain refinement, dislocation hardening, and precipitation in the TMCP with in-front UFC have caused the strength increments of 36, 34 and 54 MPa over the conventional TMCP with ACC, respectively. The microstructure characterization showed that the density of high angle grain boundaries had been increased, and the average size of precipitates had been reduced from about 34 nm to 10 nm with the cooling pattern changing from ACC to the application of UFC. The theoretical estimation indicates that when the cooling profile is changed from the conventional ACC to UFC+ACC, and to UFC, precipitation strengthening accounts for more and more strength increment in the improved strength of hot rolled micro-alloyed steels.
Zhonghua xin xue guan bing za zhi, 2006
To analyze the relationship between the early ST resolution magnitude and TIMI flow, MACE and the... more To analyze the relationship between the early ST resolution magnitude and TIMI flow, MACE and the cardiac function in ST elevated AMI (STEMI) patients after successful primary PCI. A total of 120 consecutive patients with STEMI underwent primary PCI within 12 hours after the onset of chest pain were enrolled in this study, the ST segment resolution was calculated and the patients were divided into group A (n = 81, Sigma STE resolved > or = 50%) and group B (n = 39, Sigma STE resolved < 50%). TIMI flow after PCI, clinical events up to 30 days post PCI and cardiac function 30 days post PCI were assessed. LVEF was higher in group A than that of group B (58.6% +/- 7.1% vs. 50.5% +/- 7.1%, P < 0.05). There are fewer patients with Killip III and IV in group A than in group B (1.2% vs. 12.8%, P < 0.05). The incidence of in-hospital MACE was also significantly less in group A than in group B (0 vs. 7.7%, P < 0.001). As expected, there were more patients with TIMI 3 flow (95.1...
Tensile tests of Fe-30Mn-5Si-2AI steel were carried out for different strains of O. 05, 0.14, 0.2... more Tensile tests of Fe-30Mn-5Si-2AI steel were carried out for different strains of O. 05, 0.14, 0.26, and up to the strain-to-failure in order to observe the evolution of microstructure during deformation and investigating the strain hardening behavior. Three-stage strain hardening behavior was observed in this steel during tensile test. In stage I , planar dislocation structure was observed by TEM and regarded as main deformation mechanism, and low strain hardening rate exponent was exhibited. Primary deformation twinning occurred in stage IT , and the strain hardening rate exponent increased due to the blockage of dislocations' motion by twin boundaries. In stage ill, the strain hardening rate exponent had increased to a value higher than O. 5. The obstacle effect of twin boundaries and twin-twin interaction had been observed by TEM, and the interactions between primary and secondary twins were found to cause the additional hardening in addition to the obstacle effect on dislocations' motion, which led to the twinning induced plasticity effect in the later stage of deformation.
Zhonghua xin xue guan bing za zhi, 2009
To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD... more To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD) with or without atherosclerosis (AS) and postmenopausal women with CAD. The clinical and coronary angiographic data, traditional risk factors (age, smoking, blood pressure, lipid profile, blood glucose, BMI, family history) were compared among premenopause (Pre-M, n=42) and post-menopause (Post-M, n=172) women with CAD as well as Pre-M patients with non-AS CAD (non-AS CAD, n=8). Compared with the Post-M patients with CAD, Pre-M CAD patients had significantly fewer traditional risk factors, such as hypertension, diabetes and hypercholesterolemia, significantly more acute coronary syndrome and fewer previous history of chest pain, significantly more single vessel lesion and lower Gessini score (all P < 0. 01). The logistic regression results showed that obesity is an independent risk factor for the development of CAD in premenopausal women (OR = 3. 655, 95% CI: 1. 5-11.59, P = 0.028)....
Zhonghua yi xue za zhi, Jan 22, 2010
To evaluate effect of duration of clopidogrel use on clinical follow-up outcomes in patients with... more To evaluate effect of duration of clopidogrel use on clinical follow-up outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention. A total of 214 patients with acute myocardial infarction undergoing primary percutaneous coronary intervention between January 2005 to December 2007 were enrolled. All patients were divided into two groups by duration of clopidogrel use: <1 year group (n=59) and > or =1 years group (n=155). Baseline characteristics [age, gender, angiographic characteristics, Killip classification, LVEF (left ventricular ejection fraction) , CK (creatine kinase), CK-MB, CTnI (cardiac troponin-I), hemoglobin levels and history of hypertension, diabetes, hyperlipidemia, obesity and smoking] of two groups were collected. Clinical follow-up end-point was major adverse cardiac event (MACE) including death, acute myocardial infarction, stent thrombosis and stent restenosis. Clinical follow-up duration was 41.6 +/- 16.3 mon...
Zhonghua xin xue guan bing za zhi, 2012
To observe the clinical and coronary features of patients with systemic lupus erythematosus (SLE)... more To observe the clinical and coronary features of patients with systemic lupus erythematosus (SLE) and coronary artery disease (CAD). Among 2877 SLE inpatients (age ≥ 18 years, male 363, female 2514) admitted in the Peking Union Medical College Hospital between January 1999 to October 2009, 33 patients [mean age (50.7 ± 12.8) years] were diagnosed with CAD and coronary angiogram was available in 20 out of these 33 patients. Clinical and coronary features of these patients were retrospectively reviewed. The incidence of CAD was significantly higher in male SLE patients than in female patients [2.48% (9/363) vs. 0.95% (24/2514), P = 0.022]. Patients with secondary antiphospholipid syndrome were more likely to suffer from CAD [5.76% (8/139) vs. 0.91% (25/2738), P < 0.001]. Myocardial infarction was the major form of CAD (24/33). Coronary artery angiographic changes included coronary stenosis and occlusions, coronary aneurysms and acute thrombosis and multi-vessel lesions was found in...
steel research international, 2011
A new processing route of thermo-mechanical processing (TMCP) followed by inter-critical quenchin... more A new processing route of thermo-mechanical processing (TMCP) followed by inter-critical quenching and tempering (L-T) was developed to produce 590MPa grade high strength plates based on a relatively lean composition of plain carbon manganese steels microalloyed with Nb, V and Ti. The effect of quenching temperatures on the evolution of microstructure and mechanical properties were investigated. The nanohardness measurements of martensite were performed with a nano-indenter, which indicated that the fractions of as quenched and tempered martensite increased and their hardness values decreased with increasing quenching temperatures in the range from 760 8C to 810 8C. For both as quenched and tempered samples, ferrite grain sizes decreased with increasing quenching temperature in almost linear relationships. The yield strength increased with increasing the fraction of martensite while the tensile strength remained almost unchanged, leading to the increase of yielding ratio with increasing quenching temperatures. The optimum quenching temperature was determined to be around 760 8C in terms of strengths and yield ratio.
steel research international, 2014
Materials Science and Engineering: A, 2014
Based on ultra fast cooling, the microstructural characteristics, precipitation behaviors and mec... more Based on ultra fast cooling, the microstructural characteristics, precipitation behaviors and mechanical properties of a low-carbon V-Ti microalloyed steel were investigated in details using optical microscope, electron back-scattered diffraction and transmission electron microscope. The results show that the ferrite grains can be slightly refined, the sheet spacings of interphase precipitation can be also slightly reduced and the number fraction of ferrite grains with higher precipitation hardening can be significantly enhanced by increasing cooling rate (by comparisons of air cooling and furnace cooling), and a ferritic steel precipitation-strengthened by nanometer-sized carbides was developed to produce hot rolled high strength steel with the tensile strength of $ 810 MPa, elongation of $ 24% and yield ratio of $ 0.82. While for furnace cooling after ultra fast cooling, its tensile strength, elongation and yield ratio is only $ 750 MPa, $ 22% and $ 0.84, respectively. The interphase precipitation in V-Ti microalloyed steel was observed, and these nanometer-sized carbides were detected as (V, Ti)C using energy dispersive X-ray spectroscopy spectra. In addition, the precipitation hardening was estimated as $ 313 MPa and $ 293 MPa for air cooling and furnace cooling after ultra fast cooling, respectively.
Materials Letters, 2012
ABSTRACT A 3.2 wt.%Si–0.7 wt.%Al non-oriented silicon steel as-cast sheet with developed columnar... more ABSTRACT A 3.2 wt.%Si–0.7 wt.%Al non-oriented silicon steel as-cast sheet with developed columnar grains and λ-fiber (<001> ∥ ND) texture was produced by twin-roll strip casting process, and subsequently treated with cold rolling and annealing. Texture evolution at each condition was investigated using macro-/microtexture analysis. It was shown that the cold rolled sheet was characterized by pronounced {001} <110> ~{115} <110> fiber and quite weak γ-fiber (<111> ∥ ND) texture. After annealing, the recrystallization texture was dominated by desirable λ-fiber with a peak at {001} <510> together with extremely weak γ-fiber, and consequently the magnetic induction was significantly improved. It was indicated that the formation of {001} <510> recrystallization texture could be attributed to the preferred nucleation and grain growth by the strain-induced grain boundary migration (SIBM) mechanism.
Materials Letters, 2013
a b s t r a c t An 6.5 wt%Si-0.3 wt%Al non-oriented electrical steel as-cast sheet with strong co... more a b s t r a c t An 6.5 wt%Si-0.3 wt%Al non-oriented electrical steel as-cast sheet with strong columnar grains was produced by twin-roll strip casting process, and subsequently treated with hot rolling, warm rolling and annealing. It was shown that the warm rolled sheet was characterized by strong a-fiber ( o 110 4 JRD), quite weak g-fiber (o 111 4 JND) texture and inhomogeneous deformed microstructure. After annealing, desirable l-fiber (o0014 JND) mainly including {001}o 140 4 $ {001}o 010 4
Materials Characterization, 2014
An Fe-6.5 wt.% Si-0.3 wt.% Al as-cast sheet was produced by twin-roll strip casting process, then... more An Fe-6.5 wt.% Si-0.3 wt.% Al as-cast sheet was produced by twin-roll strip casting process, then treated with hot rolling, warm rolling and annealing. A detailed study of the microstructure and texture evolution at different processing stages was carried out by optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. The initial as-cast strip showed strong columnar grains and pronounced < 001 >//ND texture.
Journal of Materials Science, 2010
The microstructure evolution during thermomechanical processing of high-Nb HSLA steel has been in... more The microstructure evolution during thermomechanical processing of high-Nb HSLA steel has been investigated with laboratory investigations. Using the Gleeble 2000 thermomechanical simulator, constitutive behavior, recrystallization, and precipitation were quantified with single-and double-hit tests as well as isothermaldeformation-quenching tests. The critical strain (e c ) for the onset of dynamic recrystallization in high-Nb steel is derived and the result shows that the critical strain/peak strain ratio is as low as approximately 0.35 and tends to a constant when the effective Nb content (Nb eff = Nb -Mn/120 ? Si/94) ranges from 0.07 to 0.10. The interaction between the recrystallization and precipitation was considered to determine non-recrystallization temperature (T nr ) under various conditions and further the dependence of the T nr on initial austenite grain size, strain, and strain rate on was formulated.
Journal of Iron and Steel Research, International, 2013
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases]
To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD... more To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD) with or without atherosclerosis (AS) and postmenopausal women with CAD. The clinical and coronary angiographic data, traditional risk factors (age, smoking, blood pressure, lipid profile, blood glucose, BMI, family history) were compared among premenopause (Pre-M, n=42) and post-menopause (Post-M, n=172) women with CAD as well as Pre-M patients with non-AS CAD (non-AS CAD, n=8). Compared with the Post-M patients with CAD, Pre-M CAD patients had significantly fewer traditional risk factors, such as hypertension, diabetes and hypercholesterolemia, significantly more acute coronary syndrome and fewer previous history of chest pain, significantly more single vessel lesion and lower Gessini score (all P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0. 01). The logistic regression results showed that obesity is an independent risk factor for the development of CAD in premenopausal women (OR = 3. 655, 95% CI: 1. 5-11.59, P = 0.028). Hypertension (OR = 4.73, 95% CI: 0.991-22.589, P = 0.051) and hypercholesterolemia (OR = 4.68, 95% CI: 0.971-22.564, P = 0.055) might also contribute to the development of CAD in these patients. Clinical characteristics were similar between Pre-M and non-AS CAD patients (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). Pre-M CAD patients had less traditional risk factors and lower coronary lesion score compared to post-M CAD patients. Obesity is an independent risk factor for Pre-M CAD. Non-AS coronary artery disease is also an important reason for the development of coronary arterial events in premenopausal women.
Acta Metallurgica Sinica -Chinese Edition-
Advanced Materials Research, 2011
Cailiao Gongcheng/Journal of Materials Engineering
Precipitation behaviors at ferrite phase zone for Nb bearing steel under ultra fast cooling condi... more Precipitation behaviors at ferrite phase zone for Nb bearing steel under ultra fast cooling conditions were investigated by using Gleeble-3800 thermomechanical simulator. Corresponding models were also obtained by considering solid solubility of Nb(C, N) and diffusion coefficient at ferrite phase zone. The results indicate that entering ultra fast cooling immediately and cooling to 650(ferrite phase zone) after rolling can restrain precipitation of Nb at austenite phase zone and realize precipitation at ferrite phase zone. Compared with precipitation behavior at austenite phase zone, the number of precipitates increases and sizes of precipitates are refined obviously at ferrite phase zone. The density of precipitates increases from 79 number·μm-2 to 373 number·μm2 and sizes of precipitates are refined from 12.9nm to 8.1nm. This can embody the effect of precipitation strengthening. The temperature of the maximum nucleation rate and the fastest precipitation are about 620 and 700 for ...
Key Engineering Materials, 2013
Materials Science Forum, 2013
Based on ultra fast cooling, effects of cooling paths on microstructure and mechanical properties... more Based on ultra fast cooling, effects of cooling paths on microstructure and mechanical properties of vanadium bearing microalloyed steel were investigated by the observation of optical microscope and scanning electron microscope and the testing of mechanical properties, moreover, the work-hardening exponent was determined based on stress-strain curves. The results show that using ultra fast cooling can effectively refine ferrite grain size and the ferrite grain size is decreased as the final temperature of ultra fast cooling is decreased. In addition, the microstructure and mechanical properties can be controlled by cooling paths. The ferrite-perlite microstructure with lower strength and higher n-value of approx. 0.2 and the ferrite-bainite microstructure with higher strength and lower n-value of approx. 0.16 can be gained at the higher and lower final temperature of ultra fast cooling, respectively. And the yield ratio are all lower than 0.85.
Materials Science Forum, 2012
ABSTRACT Thermo-mechanical Controlled Processing (TMCP) is one of the greatest achievements in st... more ABSTRACT Thermo-mechanical Controlled Processing (TMCP) is one of the greatest achievements in steel industry in the 20th century, which, however, depends too much upon low temperature rolling for the refinement of austenite grains, causing great loss in terms of productivity. To overcome this disadvantage, a new processing route with ultra fast cooling as the core has been proposed, and pilot rolling and industrial trials were carried out. As compared to conventional accelerated cooling, the ultra fast cooling can achieve cooling rate up to 300°C/s for 3 mm thick strip and highly homogeneous cooling by the pressurized water spraying. In the present work, the metallurgical backgrounds for ultra fast cooling in thermo-mechanical processing were studied and elucidated. By the pilot hot rolling experiments with a lean composition of a typical 600 MPa grade high strength steel, it has been found that the application of ultra fast cooling (UFC) at the exit of hot rolling mills can improve the strength by as much as 100 MPa as compared to the conventional TMCP. The strengthening mechanism lies in that the ultra fast cooling immediately after hot rolling may further improve the strengthening effects by precipitation, grain refinement, and dislocation hardening. The theoretical calculations and experiments indicate that the grain refinement, dislocation hardening, and precipitation in the TMCP with in-front UFC have caused the strength increments of 36, 34 and 54 MPa over the conventional TMCP with ACC, respectively. The microstructure characterization showed that the density of high angle grain boundaries had been increased, and the average size of precipitates had been reduced from about 34 nm to 10 nm with the cooling pattern changing from ACC to the application of UFC. The theoretical estimation indicates that when the cooling profile is changed from the conventional ACC to UFC+ACC, and to UFC, precipitation strengthening accounts for more and more strength increment in the improved strength of hot rolled micro-alloyed steels.
Zhonghua xin xue guan bing za zhi, 2006
To analyze the relationship between the early ST resolution magnitude and TIMI flow, MACE and the... more To analyze the relationship between the early ST resolution magnitude and TIMI flow, MACE and the cardiac function in ST elevated AMI (STEMI) patients after successful primary PCI. A total of 120 consecutive patients with STEMI underwent primary PCI within 12 hours after the onset of chest pain were enrolled in this study, the ST segment resolution was calculated and the patients were divided into group A (n = 81, Sigma STE resolved > or = 50%) and group B (n = 39, Sigma STE resolved < 50%). TIMI flow after PCI, clinical events up to 30 days post PCI and cardiac function 30 days post PCI were assessed. LVEF was higher in group A than that of group B (58.6% +/- 7.1% vs. 50.5% +/- 7.1%, P < 0.05). There are fewer patients with Killip III and IV in group A than in group B (1.2% vs. 12.8%, P < 0.05). The incidence of in-hospital MACE was also significantly less in group A than in group B (0 vs. 7.7%, P < 0.001). As expected, there were more patients with TIMI 3 flow (95.1...
Tensile tests of Fe-30Mn-5Si-2AI steel were carried out for different strains of O. 05, 0.14, 0.2... more Tensile tests of Fe-30Mn-5Si-2AI steel were carried out for different strains of O. 05, 0.14, 0.26, and up to the strain-to-failure in order to observe the evolution of microstructure during deformation and investigating the strain hardening behavior. Three-stage strain hardening behavior was observed in this steel during tensile test. In stage I , planar dislocation structure was observed by TEM and regarded as main deformation mechanism, and low strain hardening rate exponent was exhibited. Primary deformation twinning occurred in stage IT , and the strain hardening rate exponent increased due to the blockage of dislocations' motion by twin boundaries. In stage ill, the strain hardening rate exponent had increased to a value higher than O. 5. The obstacle effect of twin boundaries and twin-twin interaction had been observed by TEM, and the interactions between primary and secondary twins were found to cause the additional hardening in addition to the obstacle effect on dislocations' motion, which led to the twinning induced plasticity effect in the later stage of deformation.
Zhonghua xin xue guan bing za zhi, 2009
To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD... more To compare clinical characteristics among premenopausal women with coronary arterial disease (CAD) with or without atherosclerosis (AS) and postmenopausal women with CAD. The clinical and coronary angiographic data, traditional risk factors (age, smoking, blood pressure, lipid profile, blood glucose, BMI, family history) were compared among premenopause (Pre-M, n=42) and post-menopause (Post-M, n=172) women with CAD as well as Pre-M patients with non-AS CAD (non-AS CAD, n=8). Compared with the Post-M patients with CAD, Pre-M CAD patients had significantly fewer traditional risk factors, such as hypertension, diabetes and hypercholesterolemia, significantly more acute coronary syndrome and fewer previous history of chest pain, significantly more single vessel lesion and lower Gessini score (all P < 0. 01). The logistic regression results showed that obesity is an independent risk factor for the development of CAD in premenopausal women (OR = 3. 655, 95% CI: 1. 5-11.59, P = 0.028)....
Zhonghua yi xue za zhi, Jan 22, 2010
To evaluate effect of duration of clopidogrel use on clinical follow-up outcomes in patients with... more To evaluate effect of duration of clopidogrel use on clinical follow-up outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention. A total of 214 patients with acute myocardial infarction undergoing primary percutaneous coronary intervention between January 2005 to December 2007 were enrolled. All patients were divided into two groups by duration of clopidogrel use: <1 year group (n=59) and > or =1 years group (n=155). Baseline characteristics [age, gender, angiographic characteristics, Killip classification, LVEF (left ventricular ejection fraction) , CK (creatine kinase), CK-MB, CTnI (cardiac troponin-I), hemoglobin levels and history of hypertension, diabetes, hyperlipidemia, obesity and smoking] of two groups were collected. Clinical follow-up end-point was major adverse cardiac event (MACE) including death, acute myocardial infarction, stent thrombosis and stent restenosis. Clinical follow-up duration was 41.6 +/- 16.3 mon...
Zhonghua xin xue guan bing za zhi, 2012
To observe the clinical and coronary features of patients with systemic lupus erythematosus (SLE)... more To observe the clinical and coronary features of patients with systemic lupus erythematosus (SLE) and coronary artery disease (CAD). Among 2877 SLE inpatients (age ≥ 18 years, male 363, female 2514) admitted in the Peking Union Medical College Hospital between January 1999 to October 2009, 33 patients [mean age (50.7 ± 12.8) years] were diagnosed with CAD and coronary angiogram was available in 20 out of these 33 patients. Clinical and coronary features of these patients were retrospectively reviewed. The incidence of CAD was significantly higher in male SLE patients than in female patients [2.48% (9/363) vs. 0.95% (24/2514), P = 0.022]. Patients with secondary antiphospholipid syndrome were more likely to suffer from CAD [5.76% (8/139) vs. 0.91% (25/2738), P < 0.001]. Myocardial infarction was the major form of CAD (24/33). Coronary artery angiographic changes included coronary stenosis and occlusions, coronary aneurysms and acute thrombosis and multi-vessel lesions was found in...
steel research international, 2011
A new processing route of thermo-mechanical processing (TMCP) followed by inter-critical quenchin... more A new processing route of thermo-mechanical processing (TMCP) followed by inter-critical quenching and tempering (L-T) was developed to produce 590MPa grade high strength plates based on a relatively lean composition of plain carbon manganese steels microalloyed with Nb, V and Ti. The effect of quenching temperatures on the evolution of microstructure and mechanical properties were investigated. The nanohardness measurements of martensite were performed with a nano-indenter, which indicated that the fractions of as quenched and tempered martensite increased and their hardness values decreased with increasing quenching temperatures in the range from 760 8C to 810 8C. For both as quenched and tempered samples, ferrite grain sizes decreased with increasing quenching temperature in almost linear relationships. The yield strength increased with increasing the fraction of martensite while the tensile strength remained almost unchanged, leading to the increase of yielding ratio with increasing quenching temperatures. The optimum quenching temperature was determined to be around 760 8C in terms of strengths and yield ratio.
steel research international, 2014
Materials Science and Engineering: A, 2014
Based on ultra fast cooling, the microstructural characteristics, precipitation behaviors and mec... more Based on ultra fast cooling, the microstructural characteristics, precipitation behaviors and mechanical properties of a low-carbon V-Ti microalloyed steel were investigated in details using optical microscope, electron back-scattered diffraction and transmission electron microscope. The results show that the ferrite grains can be slightly refined, the sheet spacings of interphase precipitation can be also slightly reduced and the number fraction of ferrite grains with higher precipitation hardening can be significantly enhanced by increasing cooling rate (by comparisons of air cooling and furnace cooling), and a ferritic steel precipitation-strengthened by nanometer-sized carbides was developed to produce hot rolled high strength steel with the tensile strength of $ 810 MPa, elongation of $ 24% and yield ratio of $ 0.82. While for furnace cooling after ultra fast cooling, its tensile strength, elongation and yield ratio is only $ 750 MPa, $ 22% and $ 0.84, respectively. The interphase precipitation in V-Ti microalloyed steel was observed, and these nanometer-sized carbides were detected as (V, Ti)C using energy dispersive X-ray spectroscopy spectra. In addition, the precipitation hardening was estimated as $ 313 MPa and $ 293 MPa for air cooling and furnace cooling after ultra fast cooling, respectively.
Materials Letters, 2012
ABSTRACT A 3.2 wt.%Si–0.7 wt.%Al non-oriented silicon steel as-cast sheet with developed columnar... more ABSTRACT A 3.2 wt.%Si–0.7 wt.%Al non-oriented silicon steel as-cast sheet with developed columnar grains and λ-fiber (<001> ∥ ND) texture was produced by twin-roll strip casting process, and subsequently treated with cold rolling and annealing. Texture evolution at each condition was investigated using macro-/microtexture analysis. It was shown that the cold rolled sheet was characterized by pronounced {001} <110> ~{115} <110> fiber and quite weak γ-fiber (<111> ∥ ND) texture. After annealing, the recrystallization texture was dominated by desirable λ-fiber with a peak at {001} <510> together with extremely weak γ-fiber, and consequently the magnetic induction was significantly improved. It was indicated that the formation of {001} <510> recrystallization texture could be attributed to the preferred nucleation and grain growth by the strain-induced grain boundary migration (SIBM) mechanism.
Materials Letters, 2013
a b s t r a c t An 6.5 wt%Si-0.3 wt%Al non-oriented electrical steel as-cast sheet with strong co... more a b s t r a c t An 6.5 wt%Si-0.3 wt%Al non-oriented electrical steel as-cast sheet with strong columnar grains was produced by twin-roll strip casting process, and subsequently treated with hot rolling, warm rolling and annealing. It was shown that the warm rolled sheet was characterized by strong a-fiber ( o 110 4 JRD), quite weak g-fiber (o 111 4 JND) texture and inhomogeneous deformed microstructure. After annealing, desirable l-fiber (o0014 JND) mainly including {001}o 140 4 $ {001}o 010 4
Materials Characterization, 2014
An Fe-6.5 wt.% Si-0.3 wt.% Al as-cast sheet was produced by twin-roll strip casting process, then... more An Fe-6.5 wt.% Si-0.3 wt.% Al as-cast sheet was produced by twin-roll strip casting process, then treated with hot rolling, warm rolling and annealing. A detailed study of the microstructure and texture evolution at different processing stages was carried out by optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. The initial as-cast strip showed strong columnar grains and pronounced < 001 >//ND texture.
Journal of Materials Science, 2010
The microstructure evolution during thermomechanical processing of high-Nb HSLA steel has been in... more The microstructure evolution during thermomechanical processing of high-Nb HSLA steel has been investigated with laboratory investigations. Using the Gleeble 2000 thermomechanical simulator, constitutive behavior, recrystallization, and precipitation were quantified with single-and double-hit tests as well as isothermaldeformation-quenching tests. The critical strain (e c ) for the onset of dynamic recrystallization in high-Nb steel is derived and the result shows that the critical strain/peak strain ratio is as low as approximately 0.35 and tends to a constant when the effective Nb content (Nb eff = Nb -Mn/120 ? Si/94) ranges from 0.07 to 0.10. The interaction between the recrystallization and precipitation was considered to determine non-recrystallization temperature (T nr ) under various conditions and further the dependence of the T nr on initial austenite grain size, strain, and strain rate on was formulated.
Journal of Iron and Steel Research, International, 2013