Intragranular and Intergranular Crack Propagation in Nanocrystalline Ni Under Single-Cycle Mode I Loading

Yan Feng,Jie Li,Xinhua Yang 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

As the first step to study the fatigue crack propagation, the molecular simulations were performed to investigate theopening, propagation and closure behaviors of intragranular and intergranular cracks in nanocrystalline Ni under single-cyclemode I loading. The atomic crack angle was proposed to characterize the crack-tip blunting and sharpening quantitatively. There are obvious different mechanisms between intragranular and intergranular crack propagation. Intragranular crack propagationcould be induced by stacking faults and can change its direction very easily, but the intergranular crack perpendicularto the loading direction would propagate along the grain boundary and encounter strong resistance at the triple junction. New cracks could form in the grain boundaries ahead of the original crack. Different from the traditional understanding forintragranular and intergranular cracks, however, the dislocation density increases even in the unloading process and the cracktip is possibly sharpened temporarily during loading.

Identification and characterization of heat shock proteins in a parasitic wasp Chouioia cuneae (Hymenoptera: Eulophidae)

Li‐Na Pan,Feng-ZhuWANG,Xin-Yue ZHANG,Yan-Ni ZHAO,Geng-Ping ZHU,Min LI 한국곤충학회 2018 Entomological Research Vol.48 No.3

Heat shock proteins (HSPs) are known to be induced in response to various stress factors. Although HSPs have been studied in a number of insects, not much is known about HSPs in the natural enemies of insects, especially parasitoids. In this study, we identified and characterized five full‐length HSP genes (Cchsp40, Cchsp60, Cchsp70, Cchsp83, and Cchsp90) from an endoparasitic chalcid wasp, Chouioia cunea, which parasitizes the fall webworm, Hyphantria cunea pupae, a worldwide pest. The expression of Cchsps in response to temperature, pesticide stresses and UV radiation were also investigated by quantitative real‐time polymerase chain reaction (RT‐qPCR). The results showed that all five Cchsps were induced in response to hot and cold temperatures. Four pesticides induced the abundant expression of Cchsp70, Cchsp83 and Cchsp90 while ultraviolet radiation up‐regulated Cchsp40, Cchsp70, Cchsp83 and Cchsp90. These results indicate the different transcriptional profiles of the five different Cchsps in response to various abiotic stresses. The findings of this study provide insights into the response of C. cunea to abiotic stresses and insight into the use of this parasitoid in biological control strategies.

Improved lithium storage performance of CeO2-decorated SrLi2Ti6O14 material as an anode for Li-ion battery

Ying Li,Hong-Yan Liu,Ling-Na Shi,Yan-Rong Zhu,Ting-Feng Yi 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-

In this work, the CeO2-decorated SrLi2Ti6O14 anode was successfully prepared through a solid-state process. The space-charge effect induced by the internal adsorption of ions on the CeO2 surface can easilyresult in a formation of an excellent conductive interfacial layer between CeO2 and SrLi2Ti6O14. The goodelectrical contact between CeO2 and SrLi2Ti6O14 offers more active sites for the electrolyte storage andredox reaction, and promotes the intercalation/deintercalation of lithium ions, and thus improves therate performance and cycle stability. Due to its unique structure and composition, the CeO2-decoratedSrLi2Ti6O14 composites exhibit high reversible capacities, good cycle performance and outstanding rateperformance. Especially, the CeO2 (5 wt%)-decorated SrLi2Ti6O14 anode shows the most excellent electrochemicalperformance, which delivers a large charge capacity of 121.3 mAh g 1 and a capacity retentionof 94.48% after 100 cycles at 0.5 A g 1. However, the corresponding charge capacity and capacity retentionof pristine SrLi2Ti6O14 are 100.5 mAh g 1 and 86.77%, respectively. The CeO2(5 wt%)-decoratedSrLi2Ti6O14 with enhanced rate capacity, cycle stability and structural stability is a potential electrodematerial candidate for Li-ion battery.

Preparation of lithium-doped NaV6O15 thin film cathodes with high cycling performance in SIBs

Xu Hai-Yan,Ruan Jun Hai,Liu Fang Lin,Li Dong-Cai,Zhang Feng-Jun,Wang Ai-Guo,Sun Dao-Sheng,오원춘 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.3

Lithium ions-doped NaV6O15 thin films have been prepared using a simple low temperature liquid phase deposition method and subsequent annealing process. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), scanning elec- tron microscopy (SEM), and photoelectron spectroscopy (XPS) have been used to study the structural and physicochemical characteristics of the NaV6O15 film. The films were grown on the FTO conductive glass and used directly as an electrode of sodium ion batteries. The prepared lithium ions-doped NaV6O15 thin film electrodes showed an excellent cycling stability and discharge capacity, which may be attributed to the stability of the Li+ embedded into the gap between the V–O layers to maintain the structure and its stable β-phase structure transformed after the first cycle. The cycling stability greatly improved with increasing annealing temperature, while the discharge capacity decreased. The capacities of the film electrodes annealed at 400 °C and 450 °C maintained above 97% after 100 cycles. The lithium-doped NaV6O15 underwent a phase transition dur- ing the first charge/discharge cycle. The new transformed phase has perfect crystal structure stability undergoing insertion and deinsertion of Na+. Therefore, the lithium-doped NaV6O15 thin film possesses good cycling stability and is expected to be a promising thin film cathode for sodium-ion batteries.

Fabrication and Characterization of Copper Nanoparticles in PVA/PAAm IPNs and Swelling of the Resulting Nanocomposites

Yan-Ling Luo,Li-Li Chen,Feng Xu,Qiang-Suo Feng 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.5

Well-dispersed copper nanoparticles were fabricated using poly(vinyl alcohol)/polyacrylamide interpenetrating polymer networks (PVA/PAAm IPNs) as a nanoreactor template. The synthesis of the IPNs hydrogels was achieved in the presence of glutaraldehyde and N,N'-methylene-bis-acrylamide. The resulting PVA/PAAm/Cu nanocomposite hydrogels were characterized, and the swelling and mechanical properties were investigated. The results indicated that the copper nanoparticles had a spherical shape with a size range from 10 to 20 nm. The complexation of PVA in PVA/PAAm IPNs with Cu 2+played an important role in avoiding the aggregation of copper nanoparticles and providing particle size and size distribution controllability and stability. Although the swelling capacity of the nanocomposite hydrogels was slightly lower than that of the control, they had better compression mechanical properties. The water uptake and mechanical properties can be easily tuned by changing the component ratios to meet the requirements of specific applications, such as drug controlled release or tissue engineering.

Analysis of Different Activation Statuses of Human Mammary Epithelial Cells from Young and Old Groups

Feng, Chen-Chen,Chen, Li-Na,Chen, Mei-Jun,Li, Wan,Jia, Xu,Zhou, Yan-Yan,He, Wei-Ming Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8

Human mammary epithelial cells have different proliferative statuses and demonstrate a close relationship with age and cell proliferation. Research on this topic could help understand the occurrence, progression and prognosis of breast cancer. In this article, using significance analysis of a microarray algorithm, we analyzed gene expression profiles of human mammary epithelial cells of different proliferative statuses and different age groups. The results showed there were significant differences in gene expression in the same proliferation status between elderly and young groups. Three common differentially expressed genes were found to dynamically change with the proliferation status and to be closely related to tumorigenesis. We also found elderly group had less status-related differential genes from actively proliferating status to intermediate status and more statusrelated differential genes from intermediate status than the young group. Finally, functional enrichment analyses allowed evaluation of the detailed roles of these differentially-expressed genes in tumor progression.

Numerical Simulation on New Conical Spray for Diesel Premixed Charge Compression Ignition

( Li Yan Feng ),( Wu Qiang Long ),( Bao Guo Du ),( Xian Yin Leng ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-

Concerning the difficulty of pre-mixture preparation for diesel HCCI combustion, a new conical spray is proposed. The new conical spray is formed by the combination of multi-hole nozzle and close impingement structure. The new spray has characteristics of high dispersion and acts with flexible penetration in design. Three-dimensional CFD package AVL FIRE 8.2 was used to simulate pre-mixture preparation process with the new conical spray. The effects of combustion chamber shape and impingement structure on pre-mixture quality were analyzed. The calculation results indicate the following conclusions: (1) with the application of new conical spray, fuel impingement and adhesion on piston or liner surface are avoided; (2) combustion chamber shape has crucial effect on pre-mixture homogeneity, which is apparent when start of injection is or later than 60°CA BTDC; (3) compared with other kinds of combustion chamber, deep reentrant combustion chamber performs better on pre-mixture preparation if the start of injection is 60° or 80°CA BTDC; (4) the geometry of impingement orientation structure also affects pre-mixture quality.

Impact of sorption functional media (SFM) from zeolite tailings on the removal of ammonia nitrogen in a biological aerated filter

Yan Feng,Yanzhen Yu,Liping Qiu,Yawen Yang,Zhigang Li,Miaowan Li,Lisha Fan,Yuzhong Guo 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Haydite and sorption functional media (SFM),made of clinoptilolite tailings, were used as filter media forbiological aerated filter (BAF) to treat synthetic wastewater in parallel. The aim of this work was toevaluate impact of SFM on the removal of ammonia nitrogen in a biological aerated filter reactor underammonium nitrogen shock loads. It could be demonstrated that: (1) the BAF with SFMpresented higherammonia nitrogen removal efficiency than that with haydite; (2) during the phase of higher influentconcentrations SFMs were collecting ammonia nitrogen and can buffer ammonia nitrogen loads anddampen the effluent concentration of ammonia nitrogen; (3) when the influent concentration decreasesammonia nitrogen will desorb from the SFM and can be utilized by the nitrifying bacteria growing on theSFM. Therefore, with the SFM application existing BAF unites can be upgraded and the stability of theoperation process of BAF can be improved significantly.

Isolation of Chemical Constituents from the Aerial Parts of Verbascum thapsus and Their Antiangiogenic and Antiproliferative Activities

Yan-Li Zhao,Yong-Ping Yang,Si-Feng Wang,Yang Li,Qiu-Xia He,Ke-Chun Liu,Xiao-Li Li 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.5

Phytochemical investigation of Verbascum thapsus led to the isolation and identification of one new iridoid compound named verbathasin A, along with ten known compounds. The structure and relative stereochemistry of verbathasin A were elucidated by analysis of spectroscopic data. All the isolates except 10-deoxyeucommiol and ajugol were tested for antiangiogenic and antiproliferative activities, and compounds luteolin and 3-O-fucopyranosylsaikogenin F showed promising antiproliferative activities, with an obvious effect of inducing apoptosis of A549 lung cancer cells.

Zeolite-catalyzed Isomerization of 1-Hexene to trans-2-Hexene: An ONIOM Study

Yan-Feng Li,Ji-Qin Zhu,Peng He,Peng Wang,Hui-Ping Tian,Hui Liu 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.6

Details of the double-bond isomerization of 1-hexene over H-ZSM-5 were clarified using density functional theory. It is found that the reaction proceeds by a mechanism which involves the Brønsted acid part of the zeolite solely. According to this mechanism, 1-hexene is first physically adsorbed on the acidic site, and then,the acidic proton transfers to one carbon atom of the double bond, while the other carbon atom of the double bond bonds with the Brønsted host oxygen, yielding a stable alkoxy intermediate. Thereafter, the Brønsted host oxygen abstracts a hydrogen atom from the C_6H_13 fragment and the C.O bond is broken, restoring the acidic site and yielding trans-2-hexene. The calculated activation barrier is 12.65 kcal/mol, which is in good agreement with the experimental value. These results well explain the energetic aspects during the course of double-bond isomerization and extend the understanding of the nature of the zeolite active sites.