Inhomogeneous Fatigue Characteristics of Welded Ti–6Al–4V Thick Plate by the Electron Beam Method

Haiyan Wang,Caiyou Zeng,Caiyou Zeng,Yupeng Zhang,Yu Zhou,Chunlin Dong 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

To recognize the specific safety problem brought by an increasing thickness, the layered microstructures, fatigue propertiesand the fractographies of a 100 mm-thick Ti–6Al–4V joint via electron beam welding were investigated. The results showthat the seam zone has textural and mechanical heterogeneities in the layered thickness regions. The mid layer has the lowestfatigue life and different fracture-position tendency (more broken in seam zone) due to the hybrid influences of the grain sizeand the phase fraction of α′ and β phases. The fatigue cracks initiate on the surfaces of fatigue specimens and grow in thetransgranular fracture mode. The fatigue deformation mode is adapted to the planar-slip mechanism with different degreesof dislocation blocking in distinct layers, which results in a “mid-layer favorite” crack initiation trend. Moreover, the midlayer has the highest crack propagation rate either.

Microstructure Transformation in Different Regions of Zr61.4Cu27.8Al4Ni6Y0.8 Bulk Metallic Glass Induced by Rapid Laser Welding

Haiyan Wang,Chen Yu,Wanghui Xu,Yupeng Zhang,Yanyi Ma,Yan Lin 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

An experimental study is performed on the microstructure transformation induced by rapid laser welding in the differentregions of Zr61.4Cu27.8Al4Ni6Y0.8bulk metallic glass (BMG). The laser input energy has a remarkable influence on themicrostructure and microhardness of the Zr-based BMGs. The microstructures in different regions of as-welded joints arediverse. Crystallization happens in heat-affected zone (HAZ) with crystalline dendritic phase of CuZr, which results in thedeterioration of the microhardness to 434.9 ± 17.1 HV in HAZ, much lower than that of parent material as 517 ± 5.0 HV. Meanwhile, the element profiles indicate that intragranular segregation of Cu element occurs during the crystallization process. In the center of molten zone (MZ), the structure is fully amorphous and its hardness is close to that of parent material. In the region transiting from MZ to HAZ, some nano-grains with an average size of 20–50 nm are identified. In addition,several flower-like nanostructured grains of Y2O3phase with a size ranging from 50 to 80 nm are formed in MZ’s matrix. The nanocrystallization is believed to be responsible for the enhancement of the Vickers hardness up to 560.1 ± 8.4 HV inthis region.

Mapping QTLs for Tissue Culture Response of Mature Wheat Embryos

Haiyan Jia,Dalong Yi,Jie Yu,Shulin Xue,Yang Xiang,Caiqin Zhang,Zhengzhi Zhang,Lixia Zhang,Zhengqiang Ma 한국분자세포생물학회 2007 Molecules and cells Vol.23 No.3

Performance of BMSC column with large eccentricity under natural exposure conditions

Haiyan Ma,Xiangchao ZENG,Hongfa Yu,Peng Yue,Haiwei Zhu,Chengyou Wu 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.4

As a new type of concrete material, basic magnesium sulfate cement concrete (BMSC) has the advantages, such as early strength, high strength, good toughness and crack resistance. However, it is unclear about the degradation of the mechanical properties of BMSC columns, which is exposed to the natural environment for several years. In order to apply this new concrete to practical engineering, six large-eccentricity compressive columns of BMSC were studied. The mechanical properties such as the crack propagation, failure morphology, lateral displacement and bearing capacity of BMSC column were studied. The results show that the degradation rate of ultimate load of BMSC column is from 6% to 7%. The degradation rate of the stiffness of the column is from 6% to 13%. With the increase of compressive strength of BMSC, the axial displacement and lateral displacement are gradually reduced. The calculation model of bearing capacity of the BMSC column under the large eccentric compression is proposed. This paper provides a reference for the application of BMSC columns in the civil engineering.

Efficient complete oxidation of acetaldehyde into CO2 over Au/TiO2 core-shell nano catalyst under UV and visible light irradiation.

Song, Haiyan,Yu, Yeon-Tea,Norby, Poul American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.10

<P>Photocatalytic degradation of acetaldehyde and its photocatalytic mechanisms over Au/TiO2 core-shell nano catalyst were, for the first time, investigated under UV and visible light irradiation. The results indicate that Au/TiO2 core-shell catalyst shows higher activity for the oxidation of acetaldehyde into CO2 under both UV and visible light irradiation comparing with P-25 and metal-deposited TiO2 photocatalysts. When Au/TiO2 core-shell catalyst is excited by UV light, the Au-core acts as the sink to restore the separated electrons, thus to improve the photoinduced charge separation; while under visible light irradiation, the mechanism can be understood as the coordinate effect of the plasmon resonance of Au-core particles and the formation of an impurity energy level induced by TiO(2-x)F(x).</P>

Neuroprotection of Dexmedetomidine against Cerebral Ischemia-Reperfusion Injury in Rats: Involved in Inhibition of NF-κB and Inflammation Response

( Lijun Wang ),( Haiyan Liu ),( Ligong Zhang ),( Gongming Wang ),( Mengyuan Zhang ),( Yonghui Yu ) 한국응용약물학회 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.4

Dexmedetomidine is an α2-adrenergic receptor agonist that exhibits a protective effect on ischemia-reperfusion injury of the heart, kidney, and other organs. In the present study, we examined the neuroprotective action and potential mechanisms of dexmedetomidine against ischemia-reperfusion induced cerebral injury. Transient focal cerebral ischemia-reperfusion injury was induced in Sprague-Dawley rats by middle cerebral artery occlusion. After the ischemic insult, animals then received intravenous dexmedetomidine of 1 mg/kg load dose, followed by 0.05 mg/kg/min infusion for 2 h. After 24 h of reperfusion, neurological function, brain edema, and the morphology of the hippocampal CA1 region were evaluated. The levels and mRNA expressions of interleukin-1b, interleukin-6 and tumor nevrosis factor-α as well as the protein expression of inducible nitric oxide synthase, cyclooxygenase-2, nuclear factor-κBp65, inhibitor of κBα and phosphorylated of κBα in hippocampus were assessed. We found that dexmedetomidine reduced focal cerebral ischemia-reperfusion injury in rats by inhibiting the expression and release of inflammatory cytokines and mediators. Inhibition of the nuclear factor-κB pathway may be a mechanism underlying the neuroprotective action of dexmedetomidine against focal cerebral I/R injury.

A study of the behavior of MUA-coated Au colloid in ethanol solution

Yeon-Tae Yu,Haiyan Song,Young-Min Lim,Hyun-Woo Kwon,Min-Sang Lee 한양대학교 세라믹연구소 2007 Journal of Ceramic Processing Research Vol.8 No.5

A stable gold colloid dispersed in ethanol solution was prepared by coating with MUA. The stability of MUA-gold particles in the ethanol solution was studied using UV-Vis absorption spectra, which were affected by the MUA concentration, water concentration, initial particle size of the gold and heat treatment. A stable MUA-gold colloid in ethanol was obtained when the concentrations of MUA and water were 0.02 mM and 16.7 M, respectively. The small sizes of the gold particles before encapsulation and a low temperature were preferable for the stability of MUA-gold particles in the ethanol solution. A stable gold colloid dispersed in ethanol solution was prepared by coating with MUA. The stability of MUA-gold particles in the ethanol solution was studied using UV-Vis absorption spectra, which were affected by the MUA concentration, water concentration, initial particle size of the gold and heat treatment. A stable MUA-gold colloid in ethanol was obtained when the concentrations of MUA and water were 0.02 mM and 16.7 M, respectively. The small sizes of the gold particles before encapsulation and a low temperature were preferable for the stability of MUA-gold particles in the ethanol solution.

Electric Fenton technology with Jacaranda fruit shell biochar as particle electrode for the removal of emerging pollutant ciprofloxacin hydrochloride

Yuqin Liu,Yu Shi,Yongqiang Liu,Ailin Fan,Bo Xu,Haiyan Qiu,Guihong Lan,Ming Zhang 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.6

The overuse of antibiotics has become a serious environmental problem, and addressing how to remove antibiotics from aquatic environments poses a significant challenge. This study prepared a porous biochar material (BSJ) using natural Jacaranda fruit shells as raw materials and combined it with an electric Fenton system (EF-BSJ) to degrade ciprofloxacin hydrochloride (CIP). Characterization and analysis of biochar using SEM, BET, Raman spectroscopy, and other methods revealed that the porous structure and aromatic functional groups of biochar play a crucial role in adsorbing CIP. The effects of carbonization temperature and carbonization time on the adsorption of CIP by biochar were investigated during the biochar preparation process. At 800℃ and 1.5 hours, the maximum adsorption efficiency of biochar for CIP is 96.88%. In addition, thestudy investigated the impact of cathode and anode materials of the EF-BSJ system on the degradation efficiency of CIP. When platinum-titnium plating was used as the anode and foam nickel electrode as the cathoded, the CIP removal rate could reach 95.48%. Finally, the UV full-band scanning method was used to determine that CIP was degraded into small molecule substances, achieving the goal of removing CIP. This study introduces a novel strategy for eliminating antibiotics.

Neuroprotection of Dexmedetomidine against Cerebral Ischemia-Reperfusion Injury in Rats: Involved in Inhibition of NF-κB and Inflammation Response

Wang, Lijun,Liu, Haiyan,Zhang, Ligong,Wang, Gongming,Zhang, Mengyuan,Yu, Yonghui The Korean Society of Applied Pharmacology 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.4

Dexmedetomidine is an ${\alpha}2$-adrenergic receptor agonist that exhibits a protective effect on ischemia-reperfusion injury of the heart, kidney, and other organs. In the present study, we examined the neuroprotective action and potential mechanisms of dexmedetomidine against ischemia-reperfusion induced cerebral injury. Transient focal cerebral ischemia-reperfusion injury was induced in Sprague-Dawley rats by middle cerebral artery occlusion. After the ischemic insult, animals then received intravenous dexmedetomidine of $1{\mu}g/kg$ load dose, followed by $0.05{\mu}g/kg/min$ infusion for 2 h. After 24 h of reperfusion, neurological function, brain edema, and the morphology of the hippocampal CA1 region were evaluated. The levels and mRNA expressions of interleukin-$1{\beta}$, interleukin-6 and tumor nevrosis factor-${\alpha}$ as well as the protein expression of inducible nitric oxide synthase, cyclooxygenase-2, nuclear factor-${\kappa}Bp65$, inhibitor of ${\kappa}B{\alpha}$ and phosphorylated of ${\kappa}B{\alpha}$ in hippocampus were assessed. We found that dexmedetomidine reduced focal cerebral ischemia-reperfusion injury in rats by inhibiting the expression and release of inflammatory cytokines and mediators. Inhibition of the nuclear factor-${\kappa}B$ pathway may be a mechanism underlying the neuroprotective action of dexmedetomidine against focal cerebral I/R injury.

A prevalence survey of Wolbachia in Polytremis fukia (Lepidoptera: Hesperiidae)

Weibin Jiang,Yajuan Wu,Haiyan He,Jianqing Zhu,Weidong Yu 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2

Wolbachia are endosymbiotic bacteria that infect arthropod and nematode hosts. Only a few studies have been made on Wolbachia in butterflies. In this study, we identified and determined the molecular characteristics of Wolbachia strains in Polytremis fukia (Lepidoptera: Hesperiidae), from seven locations in China. We also sequenced three portions of the mitochondrial DNA from the individuals of P. fukia to infer the effect of Wolbachia on host mitochondrial variation. The results show that 47% (15/32) are Wolbachia positive among all specimens. The infection rates in female and male are 69% (11/16) and 25% (4/16). Phylogenetic analysis of variation in the ftsZ gene from the two strains of Wolbachia (wFuk1 and wFuk2) showed they belonged to supergroup A. On the phylogeny of the mitochondrialDNA fromP. fukia, the sequences are split into three clades. Clade I and II are consistent with the distribution of geographical population. Clade III consists of eight females invariably infected with wFuk1which showed aweak association existed between mitochondrial DNA haplotypes andwFuk1 infection status.