The mechanism of improving compressive strength of magnetite pellet by adding boron-bearing iron concentrate was studied. Boron-bearing iron concentrate and magnetite were mixed, pelletized and roasted under differ en...The mechanism of improving compressive strength of magnetite pellet by adding boron-bearing iron concentrate was studied. Boron-bearing iron concentrate and magnetite were mixed, pelletized and roasted under differ ent roasting conditions. Then, compressive strength of pellets was tested, and polished sections of the roasted pellets were analyzed from the perspective of mineralogy. Finally, the effects of different proportions, roasting temperatures and roasting time of boron-bearing iron concentrate on the compressive strength of magnetite pellets were investigated and explained.展开更多
Here,bulk CoCrFeMnNi high-entropy alloy was prepared via laser melting deposition,and its microstructure and mechanical properties at room and cryogenic temperature were investigated by a series of microstructural cha...Here,bulk CoCrFeMnNi high-entropy alloy was prepared via laser melting deposition,and its microstructure and mechanical properties at room and cryogenic temperature were investigated by a series of microstructural character-izations and mechanical tests.The results showed that the as-built samples possessed a single fcc phase and highly dense microstructures.Compared to the mechanical prop-erties at room temperature,tensile properties,microhard-ness and wear resistance of the as-built samples showed a signiflcant enhancement at cryogenic temperature,which was attributed to the deformation mechanism converting from dislocation slipping to deformation twinning at cryogenic temperature.The formation of deformation nanotwins signiflcantly improved the deformation resis-tance in cryogenic conditions,and the sliding wear in the liquid nitrogen could decrease the oxygen concentration,suppress the generation of oxide particles and thus enhance the wear resistance.展开更多
Chromosomal abnormalities and Y chromosome microdeletions are considered to be the two more common genetic causes of spermatogenic failure.However,the relati on ship between chromosomal aberrations and Y chromosome mi...Chromosomal abnormalities and Y chromosome microdeletions are considered to be the two more common genetic causes of spermatogenic failure.However,the relati on ship between chromosomal aberrations and Y chromosome microdeletio ns is still un clear.This study was to investigate the incidenee and characteristics of chromosomal aberrations and Y chromosome microdeletions in infertile men,and to explore whether there was a correlation between the two genetic defects of spermatogenic failure.A 7-year retrospective study was conducted on 5465 infertile men with nonobstructive azoospermia or oligozoospermia.Karyotype analysis of peripheral blood lymphocytes was performed by standard G-banding techniques.Y chromosome microdeletions were screened by multiplex PCR amplification with six specific sequence-tagged site(STS)markers.Among the 5465 infertile men analyzed,371(6.8%)had Y chromosome microdeletions and the prevalence of microdeletions in azoospermia was 10.5%(259/2474)and in severe oligozoospermia was 6.3%(107/1705).A total of 4003(73.2%)infertile men underwent karyotyping;370(9.2%)had chromosomal abnormalities and 222(5.5%)had chromosomal polymorphisms.Karyotype analysis was performed on 272(73.3%)patients with Y chromosome microdeletions and 77(28.3%)had chromosomal aberrations,all of which involved sex chromosomes but not autosomes.There was a sign ifica nt d iff ere nee in the frequency of chromosomal abno rmalities betwee n men with and without Y chromosome microdeletions(P<0.05).展开更多
基金the National Key Research and Development Program of China(No.2016YFC1000703)the Medicine and Health Science and Technology Plan Projects in Zhejiang Province(No.2014KYA246)the National Natural Science Foundation of China(Nos.81801441 and 81300532)
基金Item Sponsored by National Natural Science Foundation of China(51204013)Fundamental Research Funds for Central Universities of China(FRF-TP-12-020A)
文摘The mechanism of improving compressive strength of magnetite pellet by adding boron-bearing iron concentrate was studied. Boron-bearing iron concentrate and magnetite were mixed, pelletized and roasted under differ ent roasting conditions. Then, compressive strength of pellets was tested, and polished sections of the roasted pellets were analyzed from the perspective of mineralogy. Finally, the effects of different proportions, roasting temperatures and roasting time of boron-bearing iron concentrate on the compressive strength of magnetite pellets were investigated and explained.
基金the National Natural Science Foundation of China(Nos.52171154,52071118,51871076 and 51827801)the National Key Research and Development Program of China(No.2018YFB1105200)。
文摘Here,bulk CoCrFeMnNi high-entropy alloy was prepared via laser melting deposition,and its microstructure and mechanical properties at room and cryogenic temperature were investigated by a series of microstructural character-izations and mechanical tests.The results showed that the as-built samples possessed a single fcc phase and highly dense microstructures.Compared to the mechanical prop-erties at room temperature,tensile properties,microhard-ness and wear resistance of the as-built samples showed a signiflcant enhancement at cryogenic temperature,which was attributed to the deformation mechanism converting from dislocation slipping to deformation twinning at cryogenic temperature.The formation of deformation nanotwins signiflcantly improved the deformation resis-tance in cryogenic conditions,and the sliding wear in the liquid nitrogen could decrease the oxygen concentration,suppress the generation of oxide particles and thus enhance the wear resistance.
基金We should like to thank our patients for agreeing to donate their personal data and allowing the data to be published.We are grateful to Dr.Jiong Gao(BGI Genomics,BGI-Shenzhen,Shenzhen,China)for improving the article.The study was funded by the National Key Research and Development Program of China(Grant No.2018YFC1004903,and 2016YFC1000703)Key Research and Development Program of Zhejiang Province(Grant No.2019C03025)+1 种基金the National Nature Science Foundation of China(Grant No.81801441)and Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ19H090019).
文摘Chromosomal abnormalities and Y chromosome microdeletions are considered to be the two more common genetic causes of spermatogenic failure.However,the relati on ship between chromosomal aberrations and Y chromosome microdeletio ns is still un clear.This study was to investigate the incidenee and characteristics of chromosomal aberrations and Y chromosome microdeletions in infertile men,and to explore whether there was a correlation between the two genetic defects of spermatogenic failure.A 7-year retrospective study was conducted on 5465 infertile men with nonobstructive azoospermia or oligozoospermia.Karyotype analysis of peripheral blood lymphocytes was performed by standard G-banding techniques.Y chromosome microdeletions were screened by multiplex PCR amplification with six specific sequence-tagged site(STS)markers.Among the 5465 infertile men analyzed,371(6.8%)had Y chromosome microdeletions and the prevalence of microdeletions in azoospermia was 10.5%(259/2474)and in severe oligozoospermia was 6.3%(107/1705).A total of 4003(73.2%)infertile men underwent karyotyping;370(9.2%)had chromosomal abnormalities and 222(5.5%)had chromosomal polymorphisms.Karyotype analysis was performed on 272(73.3%)patients with Y chromosome microdeletions and 77(28.3%)had chromosomal aberrations,all of which involved sex chromosomes but not autosomes.There was a sign ifica nt d iff ere nee in the frequency of chromosomal abno rmalities betwee n men with and without Y chromosome microdeletions(P<0.05).
