Role of Intermetallics on Fatigue Behaviuor of Stainless Steel Adhered by Sn

Jianjun Guan,Yan Zhao,Feng Liu,Jie Zhao 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.6

The fatigue property of 304 stainless steel (SS) adhered by Fe-Sn intermetallics was investigated. The microstructure of crack nucleation and crack propagation was observed, and the influence of Fe-Sn intermetallics on fatigue failure was analyzed. Fatigue tests at stress ratio of R = -1 were performed using a sine waveform at 20 Hz frequency under load control. In addition, the morphology and microfractography of the Fe-Sn intermetallics were examined under a scanning electron microscope. Results demonstrated that the adherence of the interfacial (Fe, Cr)Sn2 layer reduced the fatigue life of the 304 SS substrates. The fatigue cracks also exhibited the intergranular fracture characteristics of the intermetallics. The brittle (Fe, Cr)Sn2 intermetallics were apt to fatigue crack nucleation. The interfacial metallurgical bonding, which was caused by diffusion reaction between Fe and Sn atoms, led to crack propagation into the SS substrate.

In SR-GIXRD Study of Oxide Film Evaluation on AISI 304 Stainless Steel in High Temperature Water

Yan Zhao,Jianjun Guan,Feng Liu,Ping Liang,Congqian Cheng,Jie Zhao 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

Oxide films on AISI 304 stainless steel in high temperature and high pressure water were detected by a new method thatsynchrotron radiation grazing incidence X-ray diffraction. The morphology, phase structure, thickness and electrochemicalcorrosion resistance of the oxide films were illustrated. A empirical equation for oxide growth is applied to evaluate thechanges in film thickness. Observations suggest that small irregular granular (Fe, Cr)2O3 oxides and polyhedral block (Fe,Cr)3O4 oxides are grown on stainless steel surface. The fine inner (Fe, Cr)2O3 particles preferentially form, and the part isprecipitated by the (Fe, Cr)3O4 structure for the diffusion outward, leading to the formation of external coarse grain oxides. The average size of (Fe, Cr)2O3 is slightly oscillated with the oxidation time, and that of (Fe, Cr)3O4 oxides increases withthe increasing exposure time. The oxide film thickness is less than 500 nm for 24 h oxidation in high temperature water, andfor 240 h oxidation the thickness is less than 800 nm. Polarization and EIS test results indicate that the oxide films of (Fe,Cr)2O3 and (Fe, Cr)3O4 provides corrosion resistance for stainless steel.

Diffusion-Weighted MRI for the Initial Viability Evaluation of Parasites in Hepatic Alveolar Echinococcosis: Comparison with Positron Emission Tomography

Jianjun Zheng,Jing Wang,Jianqing Zhao,Xianyun Meng 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.1

Objective: More than 70% of hepatic alveolar echinococcosis (HAE) are inoperable. Thus, long-term, or even life-long, pharmacological treatment with benzimidazoles is necessary. For effective treatment, it is of great importance to employ imaging techniques to detect and monitor the non-resectable parasitic viability. Therefore, this study aimed to evaluate diffusion-weighted imaging (DWI) in assessing the viability of HAE in comparison to 18-fluoro-deoxyglucose (18F-FDG) positron emission tomography, combined with computed tomography (PET/CT). Materials and Methods: Positron emission tomography, computed tomography and DWI (b-values: 0, 800 s/mm2) were retrospectively analysed in eight patients with clinically-verified HAE to, generate the apparent diffusion coefficient (ADC) map. The activity of HAE lesions in both techniques were determined independently by two radiologists according to the following standard: (+), marked focally or perilesionally increased FDG uptake/high signal intensity; (−), a hepatic defect without FDG uptake/no high signal intensity. Every lesion’s maximum standardized uptake value (SUVmax) on the PET/CT images and mean ADC values on the parametric ADC maps were measured respectively. Results of PET/CT and DWI were compared on a per-lesion-basis. Pearson’s correlation coefficient was assessed for statistical analysis. Results: A total of 14 HAE lesions were detected. Eight lesions (diameter 3−15 cm) showed perilesional hyper-signal intensity on DWI. This was visualised on PET/CT as increased FDG uptake. They mainly existed in the lesion’s border with normal liver parenchyma. Five lesions (diameter < 2 cm) were detected as nodular hyperintensity on DWI and a ‘hot spot’ on PET/CT in the same distribution. One patient, who had received oral drug therapy for three years showed significantly decreased perilesional hyperintensity on the DWI and a hepatic defect without any FDG uptake on PET/CT. Pearson’s correlation coefficient indicated a significant inverse correlation of the ADC and the SUVmax (r = -0.67, p < 0.001). Conclusion: Diffusion-weighted imaging is capable of offering information on visually detecting the HAE lesions’ viability and may be useful for routine application in the initial diagnosis of HAE.

A Novel Technique of Polishing Gear Working Surface using PECMP

Jianjun YI,Jingjing ZHOU,Yujie DING,Shaohua ZHAO 한국정밀공학회 2009 International Journal of Precision Engineering and Vol. No.

Polishing is dispensable for maximizing the life and overall performance of gears. Pulse Electrochemical Mechanical Polishing (PECMP) is combined by pulse electrochemical and mechanical action, it can reduce the surface roughness value to Ra 0.02μm and even lower and meet the requirement of gear working surface(especially for gear hard surface) polishing. The processing mechanism of PECMP and its influencing factor are discussed in this paper. Some experiments are investigated to research the surface characteristics of gears polished using PECMP , their microtopography and machining texture. The results show that PECMP have many advantages over traditionally polished surfaces with regard to friction factor reduction, noise reduction, precision keeping and anti-conglutination. For the better application of PECMP, the influencing factors and future works are discussed as well.

The Effects of Seeding Rate and N Fertilizer on Dry Matter Accumulation and Grain Yield in Oats

Zhao Guiqin,Gong Jianjun,Liu Huan 한국초지조사료학회 2009 한국초지조사료학회 학술대회논문집 Vol.2009 No.08

The effects of seeding rate and N fertilizer on leaf area index, dry matter accumulation, grain yield and yield components in oats were studied using split experimental design. The results indicated t㏊t seeding rate and N fertilizer ㏊d significant influence on leaf area index, dry matter accumulation and grain yield. With the increasing seeding and fertilizer rates, leaf area index, aboveground dry matter increased significantly. Oat reached the highest grain yield under 112.5㎏/h㎡ seeding rate, N2 was the best N fertilizer treatment for oat.

Complete genome and phylogenetic analysis of bovine papillomavirus type 15 in Southern Xinjiang dairy cow

Jianjun Hu,Wanqi Zhang,Surinder Singh Chauhan,Changqing Shi,Yumeng Song,Yubing Zhao,Zhehong Wang,Long Cheng,Yingyu Zhang 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.6

Background: Bovine papilloma is a neoplastic disease caused by bovine papillomaviruses (BPVs), which were recently divided into 5 genera and at least 24 genotypes. Objectives: The complete genome sequence of BPV type 15 (BPV Aks-02), a novel putative BPV type from skin samples from infected cows in Southern Xinjiang China, was determined by collecting warty lesions, followed by DNA extraction and amplicon sequencing. Methods: DNA was analyzed initially by polymerase chain reaction (PCR) using the degenerate primers FAP59 and FAP64. The complete genome sequences of the BPV Aks-02 were amplified by PCR using the amplification primers and sequencing primers. Sequence analysis and phylogenetic analysis were performed using bio-informatic software. Results: The nucleotide sequence of the L1 open reading frame (ORF) of BPV Aks-02 was 75% identity to the L1 ORF of BPV-9 reference strain from GenBank. The complete genome consisted of 7,189 base pairs (G + C content of 42.50%) that encoded 5 early (E8, E7, E1, E2, and E4) and 2 late (L1 and L2) genes. The E7 protein contained a consensus CX2CX29CX2C zinc-binding domain and a LxCxE motif. Among the different members of this group, the percentages of the complete genome and ORFs (including 5 early and 2 late ORFs) sequence identity of BPV Aks-02 were closer to the genus Xipapillomavirus 1 of the Xipapillomavirus genus. Phylogenetic analysis and sequence similarities based on the L1 ORF of BPV Aks-02 revealed the same cluster. Conclusions: The results suggest that BPV type (BPV Aks-02) clustered with members of the Xipapillomavirus genus as BPV 15 and were closely related to Xipapillomavirus 1.

A new method of synthesis on high-quality AgGaS2 polycrystalline

Jianjun Zhang,Shifu Zhu,Beijun Zhao,Baojun Chen,Zhiyu He 한국물리학회 2010 Current Applied Physics Vol.10 No.2

High-pure, single-phase, free of voids and high mass density AgGaS2 polycrystalline was synthesized by a new method, i.e. two-temperature zone vapor-transporting together with the mechanical and melt temperature oscillation method (TVMMTOM), directly from high-purity (6 N) elements silver, gallium and sulfur with excess sulfur. The mechanism and advantages of the new method for synthesizing high-quality AgGaS2 were discussed. It is found that the polycrystalline material synthesized by the new method is superior to that synthesized by the conventional method, what is more the new method can avoid the explosion of the synthetic quartz ampoule. Adopting the modified Bridgman method an integral and crack-free AgGaS2 single crystal with diameter of 14 mm and length of 63 mm has been obtained. It was found that there was a (1 0 1) cleavage face and the four order X-ray spectrum of the {1 0 1} faces was observed. By the method of DSC analysis the melting and freezing points of the AgGaS2 single crystal were about 995 and 955 ℃. The transmission spectra of the AgGaS2 sample of 10 × 8 ×2㎣ were obtained by means of UV and IR spectrophotometer. The limiting wavelength was 470 nm and the band gap was 2.64 eV. It can be found in the infrared spectrum that the infrared transmission was above 55%from 4000 to 800 cm-1, and the infrared transmittance of the crystal is up to 63% at 10.6 lm, which is higher than that of the crystal grown using polycrystalline materials synthesized by the conventional method. The value of a in 10.6 lm was 0.267 cm-1. Above mentioned results showed that the crystal was of good quality and TVMMTOM is preferable for synthesizing high-quality AgGaS2 polycrystalline materials.

Preparation and Characterization of Sulfated TiO2/zeolite Composite Catalysts with Enhanced Photocatalytic Activity

Yuan Zhao,JingXiu Li,Ling Wang,Yanan Hao,Lin Yang,Pingting He,JianJun Xue 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.10

Sulfated TiO2 nanoparticles were successfully immobilized on zeolite through improving hydrolysis-deposition method. Microstructure, crystallization, surface state and surface area of composite catalysts were characterized by SEM, XRD, FTIR spectra, XPS and BET and the photocatalytic activity was evaluated by degradation of methyl orange under UV irradiation. We optimized these factors (SO4 -2) ions, calcination temperature and loading amount of sulfated TiO2) on photocatalytic activity and crystallization of composite photocatalysts. The results indicated that the SO4 -2 ) ions are successfully immobilized on the surface of TiO2, and sulfated TiO2/zeolite show the highest photocatalytic activity for methyl orange at the [SO4 -2]/[Ti4+] molar rate of 1:1, calcination temperature of 600 ℃ for 2 h, and sulfated TiO2 loading amount of 40%, respectively.

Fabrication of TiO₂ Microrod with Desired Shapes from Rod-like Titanium Glycolate

Han, Jianjun,Zhang, Hua,Li, Yuanzhi,Zhao, Xiujian,Chen, Hong,Wu, Zhongkui,Kim, Sun-Jae,Park, Kyeong Soon Chemical Society of Japan 2007 Chemistry letters Vol.36 No.11

<P>Rod-like titanium glycolate was prepared by poly-condensation of TiCl<SUB>4</SUB>, ethylene glycol, and water. Focusing electronic beam on one side of a titanium glycolate microrod led to bending of the micro-rod at the irradiation part. Calcination of the polymer results in formation of rod-like titania. By controlling irradiation time and changing focus position of electronic beam, we realized controllable processing of titania microrod with desired shapes, which may be find application in nano or microdevices.</P>

Complete genome and phylogenetic analysis of bovine papillomavirus type 15 in Southern Xinjiang dairy cow

Hu, Jianjun,Zhang, Wanqi,Chauhan, Surinder Singh,Shi, Changqing,Song, Yumeng,Zhao, Yubing,Wang, Zhehong,Cheng, Long,Zhang, Yingyu The Korean Society of Veterinary Science 2020 Journal of Veterinary Science Vol.21 No.2

Background: Bovine papilloma is a neoplastic disease caused by bovine papillomaviruses (BPVs), which were recently divided into 5 genera and at least 24 genotypes. Objectives: The complete genome sequence of BPV type 15 (BPV Aks-02), a novel putative BPV type from skin samples from infected cows in Southern Xinjiang China, was determined by collecting warty lesions, followed by DNA extraction and amplicon sequencing. Methods: DNA was analyzed initially by polymerase chain reaction (PCR) using the degenerate primers FAP59 and FAP64. The complete genome sequences of the BPV Aks-02 were amplified by PCR using the amplification primers and sequencing primers. Sequence analysis and phylogenetic analysis were performed using bio-informatic software. Results: The nucleotide sequence of the L1 open reading frame (ORF) of BPV Aks-02 was 75% identity to the L1 ORF of BPV-9 reference strain from GenBank. The complete genome consisted of 7,189 base pairs (G + C content of 42.50%) that encoded 5 early (E8, E7, E1, E2, and E4) and 2 late (L1 and L2) genes. The E7 protein contained a consensus CX₂CX₂₉CX₂C zinc-binding domain and a LxCxE motif. Among the different members of this group, the percentages of the complete genome and ORFs (including 5 early and 2 late ORFs) sequence identity of BPV Aks-02 were closer to the genus Xipapillomavirus 1 of the Xipapillomavirus genus. Phylogenetic analysis and sequence similarities based on the L1 ORF of BPV Aks-02 revealed the same cluster. Conclusions: The results suggest that BPV type (BPV Aks-02) clustered with members of the Xipapillomavirus genus as BPV 15 and were closely related to Xipapillomavirus 1.