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Effects of high ambient temperature on lipid metabolism in finishing pigs 被引量:2
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作者 WU Xin LI Ze-yang +4 位作者 JIA An-feng SU Hong-guang HU Chun-hong ZHANG Min-hong FENG Jing-hai 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第2期391-396,共6页
In this study,we investigated the effects of high ambient temperature on lipid metabolism in finishing pigs.Sixteen pigs((79.6±1.2) kg) were randomly assigned to two groups:(1) ambient temperature of 30℃ ... In this study,we investigated the effects of high ambient temperature on lipid metabolism in finishing pigs.Sixteen pigs((79.6±1.2) kg) were randomly assigned to two groups:(1) ambient temperature of 30℃ with ad libitum access to feed(HT;n=8) and(2) ambient temperature of 22℃ and fed the average amount consumed by eight pigs in HT group on the previous day(PF;n=8).After 21 days of constant exposure to different environmental conditions,all the pigs were euthanized,and blood and tissue samples were obtained.High ambient temperature increased the proportion of backfat(P=0.04,+21.6%)and flare fat(P〈0.01,+43.3%).Compared with pair-fed pigs,the activities of fatty acid synthase(FAS) and malic enzyme in backfat and flare fat were lower(P〈0.05) in heat-stressed pigs,as were the amounts of acetyl-CoA-carboxylase and FAS in the longissimus muscle(LM),the amount of FAS in backfat(P〈0.01),and FAS activity in the liver(P〈0.01).Ambient temperature did not affect the amount of hormone-sensitive lipase in different tissues.The amount of lipoprotein lipase in flare fat tended to be higher(P=0.09,+28.3%),and the activities of β-hydroxyacyl coenzyme A dehydrogenase in front and back of LM were lower(P〈0.01,-48.3 and-49.8%,respectively) at 30℃ than at 22℃.The plasma concentration of high-density lipoprotein tended to be lower(P=0.08),but the plasma concentrations of very low-density lipoprotein(VLDL)(P=0.09,+50.0%) and nonestesterified fatty acid(NEFA)(P=0.04,+44.2%) were higher in heat-stressed pigs.We concluded that high ambient temperature depressed de novo fatty acid synthesis in both adipose tissues and the liver.However,β-oxidation of fatty acid in skeletal muscles was also inhibited in the high-temperature environment.As a result,more plasma NEFAs were used to synthesize VLDLs in the liver and were absorbed by adipose tissues.This may be one reason that high ambient temperature enhances the accumulation of backfat and flare fat in finishing pigs. 展开更多
关键词 β-hydroxyacyl coenzyme A dehydrogenase lipoprotein lipase lipogenesis finishing pigs high ambient temperature
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Simultaneously Improving Mechanical Properties and Stress Corrosion Cracking Resistance of High-Strength Low-Alloy Steel via Finish Rolling within Non-recrystallization Temperature 被引量:4
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作者 Hongchi Ma Baijie Zhao +4 位作者 Yi Fan Kui Xiao Jinbin Zhao Xuequn Cheng Xiaogang Li 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2021年第4期565-578,共14页
The effect of hot rolling process on microstructure evolution,mechanical properties and stress corrosion cracking(SCC)resistance of high-strength low-alloy(HSLA)steels was investigated by varying the finish rolling te... The effect of hot rolling process on microstructure evolution,mechanical properties and stress corrosion cracking(SCC)resistance of high-strength low-alloy(HSLA)steels was investigated by varying the finish rolling temperature(FRT)and total rolling reduction.The results revealed granular bainite with large equiaxed grains was obtained by a total rolling reduction of60%with the FRT of 950℃(within recrystallization temperature T_(r)).The larger grain size and much less grain boundaries should account for the relatively lower strength and SCC resistance.A larger rolling reduction of 80% under the same FRT resulted in the formation of massive martensite-austenite(M/A)constituents and resultant low ductility and SCC resistance.In contrast,a good combination of strength,ductility and SCC resistance was obtained via 80% rolling reduction with the FRT of 860℃(within non-recrystallization temperature T_(nr)),probably because of the fine grain size and M/A constituents,as well as a high density of grain boundary network. 展开更多
关键词 High-strength low-alloy(HSLA)steel Finish rolling temperature Non-recrystallization temperature Stress corrosion cracking(SCC) Grain boundary character Martensite-austenite(m/a)constituents
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Influence of the finish rolling temperatures on the microstructure and texture evolution in the ferritic stainless steels 被引量:1
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作者 Fei GAO Zhenyu LIU Haitao LIU Guodong WANG 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2011年第5期343-350,共8页
The influence of the finish rolling temperature on the microstructure and texture evolution of Nb and B micro-alloyed ultra purified Cr17 ferritic stainless steels was investigated. The hot rolled bands were produced ... The influence of the finish rolling temperature on the microstructure and texture evolution of Nb and B micro-alloyed ultra purified Cr17 ferritic stainless steels was investigated. The hot rolled bands were produced by conventional rolling process and the finish rolling at relatively low temperatures or "warm rolling". The microstructure was observed by optical microscopy, scanning electron microscopy and transmission electron microscopy, and X-ray diffraction was used to characterize the texture evolution processes. The results showed that as compared to conventional hot rolling process, the warm rolling has led to the refined and homogeneous microstructure and uniform recrystallization texture along γ-fiber in final sheets, indicating that the finish rolling at relatively low temperatures can be the effective way to improve significantly the formability of final sheets. 展开更多
关键词 Ultra purified Cr17 ferritic stainless steel Finish rolling temperature MICROSTRUCTURE TEXTURE
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Effect of Finish Rolling Temperature on Microstructure and Mechanical Properties of High Grade Pipeline Steel 被引量:1
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作者 TANG Xing-chang,KANG Yong-lin,BO Yan-yan (School of Materials Science and Engineering,State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China) 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2011年第S1期625-628,共4页
The correlation among finish rolling temperature (FRT),microstructure and mechanical property of the high grade pipeline steel was investigated in this study.The microstructure of the steels with different finish roll... The correlation among finish rolling temperature (FRT),microstructure and mechanical property of the high grade pipeline steel was investigated in this study.The microstructure of the steels with different finish rolling temperatures was observed with scanning electronic microscope (SEM) and transmission electronic microscope (TEM).The martensite/austenite (M/A) islands distribution was fixed by colour metallography,and the mechanical properties of the steels were tested with quasi-static tensile testing machine.The result shows that the fraction of M/A island increased with the finish rolling temperature decreasing,and when the finish rolling temperature is 800℃,the mechanical properties are the best. 展开更多
关键词 high grade pipeline steel finish rolling temperature martensite/austenite island
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Influence of Nb on Microstructure and Property of Low-Carbon Mn-Series Air-Cooled Bainitic Steel 被引量:7
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作者 WANG Yong-wei FENG Chun XU Feng-yun BAI Bing-zhe FANG Hong-sheng 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2010年第1期49-53,共5页
The effect of Nb on the microstructure evolution of low-carbon Mn-series air cooled bainitic steels has been studied by using thermomeehanical simulation machine, SEM, and TEM observation. The results show that the am... The effect of Nb on the microstructure evolution of low-carbon Mn-series air cooled bainitic steels has been studied by using thermomeehanical simulation machine, SEM, and TEM observation. The results show that the amount of ferrites is relatively higher in the steel without Nb than that of Nb-bearing steel under same deformation conditions, and the ferrites in Nb-bearing steel are more finer. The mechanical properties of the Nb-bearing steel are higher than those of the steel without Nb at the same finishing rolling temperature (FRT), and the toughness of the Nb- bearing steel is about 100J higher than that of the steel without Nh at the finishing rolling temperature 750℃. The toughness of Nb microalloyed steel will be improved more effectively than that of the steel without Nb with the decrease of FRT. 展开更多
关键词 Mn-series bainitic steel grain boundary allotriomorphic ferrite finishing rolling temperature Nb microalloyed steel TOUGHNESS
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Correlation of Microstructure Feature with Impact Fracture Behavior in a TMCP Processed High Strength Low Alloy Construction Steel 被引量:4
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作者 Wen-Ting Zhu Jun-Jun Cui +2 位作者 Zhen-Ye Chen Yang Zhao Li-Qing Chen 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2022年第4期527-536,共10页
The present article aims at elucidating the effect of thermo-mechanical controlled processing(TMCP), especially the finish cooling temperature, on microstructure and mechanical properties of high strength low alloy st... The present article aims at elucidating the effect of thermo-mechanical controlled processing(TMCP), especially the finish cooling temperature, on microstructure and mechanical properties of high strength low alloy steels for developing superior low temperature toughness construction steel. The microstructural features were characterized by scanning electron microscope equipped with electron backscatter diffraction, and the mechanical behaviors in terms of tensile properties and impact toughness were analyzed in correlation with microstructural evolution. The results showed that the lower finish cooling temperature could lead to a considerable increase in impact toughness for this steel. A mixed microstructure was obtained by TMCP at lower finish cooling temperature, which contained much fine lath-like bainite with dot-shaped M/A constituent and less granular bainite and bainite ferrite. In this case, this steel possesses yield and ultimate tensile strengths of ~ 885 MPa and 1089 MPa, respectively, and a total elongation of ~ 15.3%, while it has a lower yield ratio of ~ 0.81. The superior impact toughness of ~ 89 J at-20 °C was obtained, and this was resulted from the multi-phase microstructure including grain refinement, preferred grain boundaries misorientation, fine lath-like bainite with dot-shaped M/A constituent. 展开更多
关键词 High strength low alloy steel Thermo-mechanical controlled processing(TMCP) Finish cooling temperature Microstructure Mechanical properties Impact toughness
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Effect of Thermomechanical Processing on Mechanical Properties of Hot Rolled Multiphase Steel 被引量:1
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作者 LI Zhuang WU Di LU Hui-sheng 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2008年第1期55-60,共6页
The effect of thermomechanical processing(TMP)on the mechanical properties of hot rolled multiphase steel was investigated.TMP was conducted using a laboratory hot rolling mill,in which three different kinds of fini... The effect of thermomechanical processing(TMP)on the mechanical properties of hot rolled multiphase steel was investigated.TMP was conducted using a laboratory hot rolling mill,in which three different kinds of finish rolling deformation degrees and temperatures were applied.The results indicate that polygonal ferrite,granular bainite,and a considerable amount of stabilized retained austenite can be obtained by TMP.The stability of the retained austenite increases with decreasing finish rolling temperature and increasing finish rolling deformation degrees.Ultimate tensile strength(σb),total elongation(δ),and the product of ultimate tensile strength by total elongation(σb·δ)for 50% reduction at finish rolling temperature of 700 ℃ reach maximum values [791 MPa,36% and 28 476(MPa·%),respectively]. 展开更多
关键词 hot rolled multiphase steel finish rolling deformation degree finish rolling temperature retained austenite mechanical property
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Effect of Thermomechanical Controlled Processing on Mechanical Properties of 490 MPa Grade Low Carbon Cold Heading Steel 被引量:1
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作者 LI Zhuang 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2009年第3期43-48,共6页
Thermomechanical controlled processing (TMCP) of low carbon cold heading steel in different austenite conditions were conducted by a laboratory hot rolling mill. Effect of various processing parameters on the mechan... Thermomechanical controlled processing (TMCP) of low carbon cold heading steel in different austenite conditions were conducted by a laboratory hot rolling mill. Effect of various processing parameters on the mechanical properties of the steel was investigated. The results showed that the mechanical properties of the low carbon cold heading steel could be significantly improved by TMCP without heat treatment. The improvement of mechanical properties can be attributed mainly to the ferrite grain refinement due to low temperature rolling. In the experiments the better ultimate tensile strength and ductility are obtained by lowering finishing cooling temperature within the temperature range from 650 ℃ to 550 ℃ since the interlamellar space in pearlite colonies become smaller. Good mechanical properties can be obtained in a proper austenite condition and thermomechanical processing parameter. The ferrite morphology has a more pronounced effect on the mechanical behavior than refinement of the microstructure. It is possible to realize the replacement of medium-carbon by low-carbon for 490 MPa grade cold heading steel with TMCP. 展开更多
关键词 thermomechanical controlled processing TMCP low carbon cold heading steel low temperature rolling finishing cooling temperature
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Microstructures and Mechanical Properties of a New Multi-functional 460 MPa Grade Construction Structural Steel 被引量:1
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作者 Zhenye Chen Zhangguo Lin +3 位作者 Jianjun Qi Yang Feng Liqing Chen Guodong Wang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2022年第7期1131-1142,共12页
This article reports a new generation of Q460 multi-functional construction structural steel,which has high strength(yield strength larger than 460 MPa),excellent toughness(higher than 110 J/cm^(2) at-60 ℃),lower yie... This article reports a new generation of Q460 multi-functional construction structural steel,which has high strength(yield strength larger than 460 MPa),excellent toughness(higher than 110 J/cm^(2) at-60 ℃),lower yield ratio(lower than 0.8),good fire resistance(yield strength at 600 ℃ larger than two-thirds of its room-temperature yield strength)and better corrosion resistance.The eff ects of finish cooling temperature(FCT)on the microstructure and properties were studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM),emission electron probe micro-analysis(EPMA),electron backscattering diff raction(EBSD),tensile tester,impact tester,periodic immersion cycle acceleration test and electrochemical experiment.The results show that the strength and toughness are simultaneously improved by decreasing the FCT due to more lath-like bainite with large number of dislocations,refined martensite/austenite(M/A)with higher carbon concentration and increased high angle boundaries.In addition,the fire resistance of the newly developed Q460 steel is obviously better than the conventional one,which is mainly due to non-recrystallized lath-like bainite with high dislocation density at elevated temperature.The corrosion resistance of the new Q460 steel is also improved due to the addition of Cu and Cr. 展开更多
关键词 Construction structural steel Thermo-mechanical controlled processing(TMCP) Finish rolling temperature Microstructure Mechanical properties
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Effects of Technological Parameters on Microstructures and Properties of Low Cost Hot Rolled Dual-Phase Steel on CSP Line 被引量:1
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作者 DONG Rui-feng 1,2,LI De-gang 1,2,YAN Bo 2,WANG Guo-dong 1 (1.The State Key Lab of Rolling and Automation,Northeastern University,Shenyang 110004,China 2.Baotou Iron and Steel (Group) Co Ltd,Compact Strip Production Plant,Baotou 014010,China) 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2011年第S1期615-620,共6页
The effects of technological parameters on microstructures and properties of low cost hot rolled dual-phase steel was researched by design different finish rolling temperature,mid cooling temperature between laminar c... The effects of technological parameters on microstructures and properties of low cost hot rolled dual-phase steel was researched by design different finish rolling temperature,mid cooling temperature between laminar cooling and UFC (ultra fast cooling) and stable UFC rate on the same gauge strips with the same chemistry composition during the manufacture process.It is the key for controlling coil temperature to control finish rolling temperature and mid cooling temperature between laminar cooling and UFC that based on stable UFC rate precondition.The lower finish rolling temperature,with mid cooling temperature between laminar cooling and UFC,the better to form martensite is.The foundation of developing the similar productions on the similar product line was supplied.It is good to technological advancement of developing high affixation value production as hot rolled DP steel,TRIP steel etc.in CSP line. 展开更多
关键词 finish rolling temperature mid cooling temperature between laminar cooling and UFC hot rolled dual-phase steel microstructures and properties
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