Effect of Al on the Microstructure and Mechanical Properties of Mg–Sn–Ca–Mn Wrought Alloy

Yun Feng,Yuanyuan Yang,Zongqi Xiao,Xianglong Meng,Guorong Zhou,Jinfeng Leng,Xinying Teng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

Mg–Sn–Ca–Mn–xAl (x = 0,1.5 wt%) alloys with ultra-fine recrystallized grains were prepared by conventional extrusion(400 °C, 0.5 mm/s). Effects of aluminum (Al) on mechanical properties and microstructure of the Mg–1Sn–1Ca–0.5Mn(wt%) alloy were systematically investigated. By the addition of 1.5 wt% Al, the yield strength of the as-extruded alloysignificantly increased from 183 to 237 MPa. The as-cast alloys show a dendritic structure consists of α-Mg, (Mg, Al)2Ca,and CaMgSn phases. The as-extruded Mg–1Sn–1Ca–0.5Mn–1.5Al alloys exhibit a bimodal grain structure composed ofdynamic recrystallized (DRXed) fine grains and coarse unDRXed grains. Compared with Al free alloy, a lot of nano-scaleplanar Al2Caand rectangle shape Al8Mn5precipitated in the as-extruded alloy with 1.5 wt% Al. Meanwhile, the addition ofAl significantly strengthened alloys’ fiber texture with < 10–10 >//ED.

Field measurements of wind pressure on an open roof during Typhoons HaiKui and SuLi

Feng, Ruoqiang,Liu, Fengcheng,Cai, Qi,Yan, Guirong,Leng, Jiabing Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.1

Full-scale measurements of wind action on the open roof structure of the WuXi grand theater, which is composed of eight large-span free-form leaf-shaped space trusses with the largest span of 76.79 m, were conducted during the passage of Typhoons HaiKui and SuLi. The wind pressure field data were continuously and simultaneously monitored using a wind pressure monitoring system installed on the roof structure during the typhoons. A detailed analysis of the field data was performed to investigate the characteristics of the fluctuating wind pressure on the open roof, such as the wind pressure spectrum, spatial correlation coefficients, peak wind pressures and non-Gaussian wind pressure characteristics, under typhoon conditions. Three classical methods were used to calculate the peak factors of the wind pressure on the open roof, and the suggested design method and peak factors were given. The non-Gaussianity of the wind pressure was discussed in terms of the third and fourth statistical moments of the measured wind pressure, and the corresponding indication of the non-Gaussianity on the open roof was proposed. The result shows that there were large pulses in the time-histories of the measured wind pressure on Roof A2 in the field. The spatial correlation of the wind pressures on roof A2 between the upper surface and lower surface is very weak. When the skewness is larger than 0.3 and the kurtosis is larger than 3.7, the wind pressure time series on roof A2 can be taken as a non-Gaussian distribution, and the other series can be taken as a Gaussian distribution.

Nanocomposite Ni–TiN coatings prepared by ultrasonic electrodeposition

Fa-feng Xia,Meng-hua Wu,Fan Wang,Zhen-yuan Jia,Ai-leng Wang 한국물리학회 2009 Current Applied Physics Vol.9 No.1

Nanocomposite Ni–TiN coatings were prepared by ultrasonic electrodeposition and the effects of ultrasonication on the coatings were studied. X-ray diffraction analysis was utilized to detect the crystalline and amorphous characteristics of the composite coatings. The surface morphology and metallurgical structure were observed by scanning electron microscopy, high-resolution transmission electron microscopy and scanning probe microscopy. The results showed that ultrasonication had great effects on TiN nanoparticles in composite coatings. The moderate ultrasonication conduced to homogeneous dispersion of TiN particles in the coatings. Moreover, the TiN nanoparticles that entered and homogeneously dispersed in the composite coating led to an increase in the number of nuclei for nucleation of nickel grains and inhibition of grain growth. Therefore, the introduction of ultrasonication and TiN nanoparticles resulted in the formation of smaller nickel grains. The average grain diameter of TiN particles was 33 nm, while Ni grains measured approximately 53 nm. Nanocomposite Ni–TiN coatings were prepared by ultrasonic electrodeposition and the effects of ultrasonication on the coatings were studied. X-ray diffraction analysis was utilized to detect the crystalline and amorphous characteristics of the composite coatings. The surface morphology and metallurgical structure were observed by scanning electron microscopy, high-resolution transmission electron microscopy and scanning probe microscopy. The results showed that ultrasonication had great effects on TiN nanoparticles in composite coatings. The moderate ultrasonication conduced to homogeneous dispersion of TiN particles in the coatings. Moreover, the TiN nanoparticles that entered and homogeneously dispersed in the composite coating led to an increase in the number of nuclei for nucleation of nickel grains and inhibition of grain growth. Therefore, the introduction of ultrasonication and TiN nanoparticles resulted in the formation of smaller nickel grains. The average grain diameter of TiN particles was 33 nm, while Ni grains measured approximately 53 nm.

Field measurements of wind pressure on an open roof during Typhoons HaiKui and SuLi

Ruoqiang Feng,Fengcheng Liu,Qi Cai,Guirong Yan,Jiabing Leng 한국풍공학회 2018 Wind and Structures, An International Journal (WAS Vol.26 No.1

Full-scale measurements of wind action on the open roof structure of the WuXi grand theater, which is composed of eight large-span free-form leaf-shaped space trusses with the largest span of 76.79 m, were conducted during the passage of Typhoons HaiKui and SuLi. The wind pressure field data were continuously and simultaneously monitored using a wind pressure monitoring system installed on the roof structure during the typhoons. A detailed analysis of the field data was performed to investigate the characteristics of the fluctuating wind pressure on the open roof, such as the wind pressure spectrum, spatial correlation coefficients, peak wind pressures and non-Gaussian wind pressure characteristics, under typhoon conditions. Three classical methods were used to calculate the peak factors of the wind pressure on the open roof, and the suggested design method and peak factors were given. The non-Gaussianity of the wind pressure was discussed in terms of the third and fourth statistical moments of the measured wind pressure, and the corresponding indication of the non-Gaussianity on the open roof was proposed. The result shows that there were large pulses in the time-histories of the measured wind pressure on Roof A2 in the field. The spatial correlation of the wind pressures on roof A2 between the upper surface and lower surface is very weak.When the skewness is larger than 0.3 and the kurtosis is larger than 3.7, the wind pressure time series on roof A2 can be taken as a non-Gaussian distribution, and the other series can be taken as a Gaussian distribution.

Comparison of Epidermal Growth Factor Receptor Mutations between Primary Tumors and Lymph Nodes in Non-small Cell Lung Cancer: a Review and Meta-analysis of Published Data

Wang, Feng,Fang, Ping,Hou, Dan-Yang,Leng, Zai-Jun,Cao, Le-Jie Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11

Background: Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) can predict the clinical response to tyrosine kinase inhibitor (TKI) therapy. However, EGFR mutations may be different in primary tumors (PT) and metastatic lymph nodes (MLN). The aim of this study was to compare EGFR mutations between PT and the corresponding MLN in NSCLC patients, and provide some guidelines for clinical treatment using TKI therapy. Materials and Methods: A systematic review and meta-analysis was performed with several research databases. Relative risk (RR) with the 95% confidence interval (CI) were used to investigate the EGFR mutation status between PT and the corresponding MLN. A random-effects model was used. Results: 9 publications involving 707 patients were included in the analysis. It was found that activation of EGFR mutations identified in PT and the corresponding MLN was 26.4% (187/707) and 19.9% (141/707), respectively. The overall discordance rate in our meta-analysis was 12.2% (86/707). The relative risk (RR) for EGFR mutation in PT relative to MLN was 1.33 (95%CI: 1.10-1.60; random-effects model). There was no significant heterogeneity between the studies ($I^2$=5%, p=0.003). Conclusions: There exists a considerable degree of EGFR mutation discrepancy in NSCLC between PT and corresponding MLN, suggesting that tumor heterogeneity might arise at the molecular level during the process of metastasis.

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.

The joint effect of different concentration of Cd<SUP>2+</SUP> and ionic liquid on the growth of wheat seedlings

Zhonglin Chen,Qian Zhou,Feng Leng,Bing Dai,Xueyang Zhao,Weichen Zhang,Neng Liu,Wei Guan,Kui Liu 대한환경공학회 2017 Environmental Engineering Research Vol.22 No.3

The joint effect of different concentrations (0.05-0.375 mmol/L) of Cd<SUP>2+</SUP> and various concentrations (50-400 mg/L) of [C3mim][OAc] on the growth and physiology of wheat seedlings were investigated. The toxicity of Cd<SUP>2+</SUP> could be significantly reduced by lower concentrations (50-200 mg/L) of [C3mim][OAc]. With higher concentration (≥ 300 mg/L) of [C3mim][OAc], the reduction became less, and compared to Cd<SUP>2+</SUP> stress only, the toxicity of 400 mg/L [C3mim][OAc] increased. As for different Cd<SUP>2+</SUP> concentrations, the optimal reduction depends on the balance between the exact concentration of Cd<SUP>2+</SUP> and [C3mim][OAc]: With low Cd<SUP>2+</SUP> concentration (0.05-0.250 mmol/L) requiring 50 mg/L [C3mim][OAc], it could reach a dynamic equilibrium, while high Cd<SUP>2+</SUP> concentration (0.375 mmol/L) requiring 100 mg/L [C3mim][OAc]. The growth and physiological indexes of wheat seedlings show a decrease in toxicity compared to the Cd alone treatment, when the dynamic equilibrium is reached. The concentration of Cd<SUP>2+</SUP> in leaf tissues showed that low concentration (50-200 mg/L) of [C3mim][OAc] can reduce the toxicity of Cd<SUP>2+</SUP> (0.05-0.375 mmol/L) by decreasing the level of Cd<SUP>2+</SUP> concentration in the tissues, whereas the higher concentration (≥ 300 mg/L) of [C3mim][OAc] can increase the concentration of Cd<SUP>2+</SUP>.

Transcriptomic and proteomic profiling revealed global changes in Streptococcus thermophilus during pH-controlled batch fermentations

Yali Qiao,Cong Leng,Gefei Liu,Yanjiao Zhang,Xuepeng Lv,Hongyu Chen,Jiahui Sun,Zhen Feng 한국미생물학회 2019 The journal of microbiology Vol.57 No.9

Understanding global changes of physiological processes at the molecular level during the growth of Streptococcus thermophilus is essential for the rational design of cultivation media and the optimization of bioprocesses. Transcriptomics and proteomics were combined to investigate the global changes at the transcript and protein level during the growth of S. thermophilus. The expression of 1396 genes (FDR ≤ 0.001) and 876 proteins (P < 0.05) changed significantly over time. The most remarkable growth phase dependent changes occurred in the late-lag phase and were related to heterofermentation, glycolysis, peptidoglycan biosynthesis, conversion between amino acids and stress response. The present results could provide theoretical guidance for high-cell-density culture, help design cultivation media, and help attain a high biomass of S. thermophilus.

Causal Relations between Exposome and Stroke: A Mendelian Randomization Study

Hong-Qi Li,Yi-Wei Feng,Yu-Xiang Yang,Xin-Yi Leng,Prof Can Zhang,Shi-Dong Chen,Kevin Kuo,Shu-Yi Huang,Xue-Qing Zhang,Yi Dong,Xiang Han,Xin Cheng,Mei Cui,Lan Tan,Qiang Dong,Jin-Tai Yu 대한뇌졸중학회 2022 Journal of stroke Vol.24 No.2

Background and Purpose To explore the causal relationships of elements of the exposome with ischemic stroke and its subtypes at the omics level and to provide evidence for stroke prevention. Methods We conducted a Mendelian randomization study between exposure and any ischemic stroke (AIS) and its subtypes (large-artery atherosclerotic disease [LAD], cardioembolic stroke [CE], and small vessel disease [SVD]). The exposure dataset was the UK Biobank involving 361,194 subjects, and the outcome dataset was the MEGASTROKE consortium including 52,000 participants. Results We found that higher blood pressure (BP) (systolic BP: odds ratio [OR], 1.02; 95% confidence interval [CI], 1.01 to 1.04; diastolic BP: OR, 1.03; 95% CI, 1.01 to 1.05; pulse pressure: OR, 1.03; 95% CI, 1.00 to 1.06), atrial fibrillation (OR, 1.18; 95% CI, 1.13 to 1.25), and diabetes (OR, 1.13; 95% CI, 1.07 to 1.18) were significantly associated with ischemic stroke. Importantly, higher education (OR, 0.69; 95% CI, 0.60 to 0.79) decreased the risk of ischemic stroke. Higher systolic BP (OR, 1.06; 95% CI, 1.02 to 1.10), pulse pressure (OR, 1.08; 95% CI, 1.02 to 1.14), diabetes (OR, 1.28; 95% CI, 1.13 to 1.45), and coronary artery disease (OR, 1.58; 95% CI, 1.25 to 2.00) could cause LAD. Atrial fibrillation could cause CE (OR, 1.90; 95% CI, 1.71 to 2.11). For SVD, higher systolic BP (OR, 1.04; 95% CI, 1.00 to 1.07), diastolic BP (OR, 1.06; 95% CI, 1.01 to 1.12), and diabetes (OR, 1.22; 95% CI, 1.10 to 1.36) were causal factors. Conclusions The study revealed elements of the exposome causally linked to ischemic stroke and its subtypes, including conventional causal risk factors and novel protective factors such as higher education.

Enhanced fermentative γ-aminobutyric acid production by a metabolic engineered Corynebacterium glutamicum

Jingbai Wen,Wanli Sun,Guihua Leng,Dan Li,Changyan Feng,Zhide Tian,Xin Wang 한국생물공학회 2024 Biotechnology and Bioprocess Engineering Vol.29 No.1

γ-Aminobutyric acid (GABA) is a non-proteinogenic amino acid with important physiological functions, which has been widely used in food, pharmaceuticals, and polyamides production. The fermentative GABA production by Corynebacterium glutamicum was recognized as one of the most promising methods. However, the problems of low catalytic activity of the heterologously expressed glutamate decarboxylase (GAD) and the imbalanced carbon fl ux between cell growth and GABA synthesis severely limited the GABA production by C. glutamicum . This study applied combinational metabolic engineering and catalytic condition optimization strategies to solve these two major obstacles. The secretory expression of GAD was enhanced using a bicistronic-designed expression cassette. This bicistronic expression cassette was further triply inserted into the genome by substituting the ldhA , pqo , and ack genes, thus stabilizing the expression of GAD and reducing the accumulation of by-products of lactate and acetate. A growth-regulated promoter P CP_2836 was applied to dynamically control the expression of odhA , thus controlling the α-oxoglutarate dehydrogenase complex activity for balanced cell growth and GABA production. The glutamate precursor synthesis and pyridoxal 5′-phosphate supply were also strengthened by promoter substitution. Finally, through a two-stage pH-controlled fed-batch fermentation under optimized conditions, the engineered strain reached GABA titer of 81.31 ± 1.31 g/L with a yield and productivity of 0.50 ± 0.01 g/g and 1.36 ± 0.23 g L −1 h −1 , which was 4.8%, 13.6%, and 11.2% higher than that of the original strain. This study laid a solid foundation for industrial fermentative GABA production by engineered C. glutamicum .