Comparative study of the microstructure of Ti-6Al-4V titanium alloy sheets under quasi-static and high-velocity bulging

Fen-Qiang Li,Jun Zhao,Jian-Hua Mo,Jian-Jun Li,Liang Huang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.3

In order to reveal the high-velocity deformation mechanisms of Ti-6Al-4V titanium alloy sheets, the dynamic deformation behavior and the microstructure evolutions were compared with those under quasi-static case employing Scanning electron microscopy/Electron back-scattered diffraction (SEM/EBSD) and Transmission electron microscopy (TEM). The results indicated that the distribution of microhardness was uneven. The cause was determined to be the non-uniform material flow and dynamic loading. The grain sizes of the Ti-6Al-4V titanium alloy sheet were nearly the same under two conditions, but the grains were elongated under the dynamic loading compared with that observed in quasi-static forming. In high-velocity bulging, dislocation slip was the principle mechanism of plastic deformation of Ti-6Al-4V titanium alloy when deformation was small. As the strain increased, the twinning phenomenon was activated in addition to the dislocation cell structure. The twinning plane was determined to be the (10 11) plane.

Three homologous genes encoding functional D8-sphingolipid desaturase in Populus tomentosa

Shu-Fen Li,Zan-Min Hu,Guo-Jun Zhang,Ying-Chun Yuan,Cong-Hui Wang,Wu-Jun Gao,Chuan-Liang Deng,Long-Dou Lu 한국유전학회 2014 Genes & Genomics Vol.36 No.3

Δ8-sphingolipid desaturase is characterized by itsability to catalyze desaturation at the C8 position of the longchainbase of sphingolipids in plants. No previous studieshave been conducted on genes encoding Δ8-sphingolipiddesaturases in the woody plant Populus tomentosa. In thisstudy, three genes that encode Δ8-sphingolipid desaturasewere isolated fromP. tomentosa. Among these genes, PtD8Aand PtD8B showed high sequence similarity; whereas PtD8Cexhibited large sequence divergence.RT-PCRresults showedthat PtD8A and PtD8B were expressed in all tissues detected,whereas PtD8C was not expressed in roots. Heterologousexpression in yeast revealed that PtD8A/B/C were functionalΔ8-sphingolipid desaturases, and can catalyze the C18-phytosphingeninedesaturation to produce 8(Z)- and 8(E)-C18-phytosphingenine.However, the conversion rate and ratios ofthe two products differed. Compared with control cells,transgenic yeasts expressing PtD8A/B/C exhibited enhancedaluminum tolerance. Our findings further elucidated thebiochemical functions and evolutionary history ofΔ8-sphingolipid desaturases in plants. Candidate genes forbreeding new poplar germplasm resources with enhancedtolerance ability to aluminium were also provided.

Clerodane furanoditerpenoids from the stems of Tinospora sinensis

Jun-Sheng Zhang,De-Feng Xu,Yin-Yin Wang,Ren-Fen Ma,Hua Zhang 대한약학회 2022 Archives of Pharmacal Research Vol.45 No.5

One new clerodane-type furanoditerpenoidtinosinoid A ( 1 ) and nine new nor-clerodane analogs tinosinoids B–J ( 2 − 10 ) have been isolated from the stems ofTinospora sinensis . The structures of the new compoundswith absolute confi gurations have been elucidated by spectroscopicmeans, including MS, NMR and ECD techniques,as well as chemical correlation. Compound 1 is a rare sulfurcontainingclerodane diterpenoid incorporating a 2-mercaptoethanolunit via a thioether bond, while compounds 4 / 5and 9 represent two pairs of unusual equilibrium regioisomersthrough an interesting intramolecular transesterifi cation. Our bioassays established that 1 and 8 displayed moderateantiproliferative eff ects against two human tumor celllines, and 9 and 10 showed signifi cant α -glucosidase inhibitoryactivities. A kinetics study revealed that compound 10was a noncompetitive α -glucosidase inhibitor, and its possiblebinding mode to the enzyme was further probed bymolecular docking experiments.

Clinical Effect of Traditional Chinese Medicine Shenhuang Granule in Critically Ill Patients with COVID-19: A Single-Centered, Retrospective, Observational Study

( Jun Feng ),( Bangjiang Fang ),( Daixing Zhou ),( Junshuai Wang ),( Dengxiu Zou ),( Gang Yu ),( Yikuan Fen ),( Dan Peng ),( Jifa Hu ),( Daqian Zhan ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.3

The coronavirus disease 2019 (COVID-19) pandemic has become a public health emergency of global concern. In China, traditional Chinese medicine has been widely administered to COVID-19 patients without sufficient evidence. To evaluate the efficacy of Shenhuang Granule (SHG) for treating critically ill patients with COVID-19, we included in this study 118 patients who were admitted to the ICU of Tongji Hospital between January 28, 2020 and March 28, 2020. Among these patients, 33 (27.9%) received standard care plus SHG (treatment group) and 85 (72.1%) received standard care alone (control group). Enrolled patients had a median (IQR) age of 68 (57-75) years, and most (79 [67.1%]) were men. At end point of this study, 83 (70.3%) had died in ICU, 29 (24.5%) had been discharged from ICU, and 6 patients (5.2%) were still in ICU. Compared with control group, mortality was significantly lower in treatment group (45.4% vs. 80%, p < .001). Patients in treatment group were less likely to develop acute respiratory distress syndrome (ARDS) (12 [36.3%] vs. 54 [63.5%], p = 0.012) and cardiac injury (5 [15.1%] vs. 32 [37.6%], p = 0.026), and less likely to receive mechanical ventilation (22 [66.7%] vs. 72 [84.7%], p = 0.028) than those in control group. The median time from ICU admission to discharge was shorter in treatment group (32 [20-73] days vs. 76 [63-79] days, p = 0.0074). These findings suggest that SHG treatment as a complementary therapy might be effective for critically ill adults with COVID-19 and warrant further clinical trials.

A Robust Finite-Horizon Kalman Filter for Uncertain Discrete Time-Varying Systems with State-Delay and Missing Measurements

Jun-Hui Zheng,Jian-Fen Liu 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.3

In this paper, a robust kalman filter is designed for the uncertainty time-varying discrete systems with state delay in process and output matrices combined with the possibility of missing measurements. The uncertainties are expected in the process, output and white noise covariance matrices. A formula for a candidate upper bound on the actual state estimation error variances for all admissible parameter uncertainties and possible missing measurements is obtained. The filter parameters are optimized to give a minimal upper bound on the state estimation error covariance for all admissible uncertainties and missing measurements.

Enhanced Whole-cell Biodehydrogenation of 11β-hydroxyl Medroxyprogesterone in a Biphasic System Containing Ionic Liquid

Jun-Yao He,Pu Wang,Yu-Fen Yang,Song-Lin Xie 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.5

A hydrophilic ionic liquid, 1-butyl-3-methylimidazolium (L)-lactate ([bmim][lactate]), was successfully employed as a co-solvent to improve the biodehydrogenation of steroid 11β-hydroxyl medroxyprogesterone (HMP)to pregna-1,4-diene-6α-methyl-3,20-dione-11β,17α-dihydroxy (PDMDD) in an aqueous-organic biphasic system using Arthrobacter simplex UR106 cells. First, a suitable biphasic system was constituted, composed of toluene and Tris-HCl buffer (0.05 mol/L, pH 7.6) at a 0.4 (V_(org)/V_(aq))volumetric phase ratio. Investigation of biodehydrogenation with the addition of [bmim][lactate] to the aqueous phase was then performed. The results demonstrate that biodehydrogenation is more efficient in a biphasic system containing 2% [bmim][lactate] as a co-solvent compared to an aqueous-toluene two-phase system. Higher bioconversion (83.2% versus 56.4%) was observed after 16 h at a substrate concentration of 80 mg HMP in 8 mL of toluene.

Optimization of the Field Shaper Parameters in Electromagnetic Pulse Crimping of Cable

Fen-Qiang Li,Jishuai Jiang,Hongsong Cheng,Jianling Xu,Xiaohong Ge,Hui Li,Jun Zhao,Yang Ran 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.10

Crimping of wires to achieve a secure connection is one of the most critical challenges in fabrication of electronic circuit boards, automobiles, aviation, satellite and communication components. The electromagnetic pulse crimping process offers great potential to successfully address these challenges. In this paper, ANSYS/Multi physical software was used to first determine the electromagnetic force distribution on the terminal lug by analyzing the magnetic field in the electromagnetic pulse crimping process. The electromagnetic force was then imported into the ABAQUS/Explicit software as the boundary condition to calculate the deformation behavior of the terminal lug barrel and cable according to the stress–strain curve of the terminal material under high strain rate. The calculated deformation result was subsequently verified by experimental data. Three main parameters of the field shaper were analyzed to determine their influence on the crimping result; slit position, the inner diameter vertical dimension and the position relationship between the terminal lug and field shaper. Then using the empirical formula we calculated and verified the inner diameter vertical dimension of the field shaper. The model proved to be reliable. Deformation of the terminal was determined to be uneven along the circumference in the crimping area. For the type of terminal lug studied, an inner diameter vertical dimension of 10 mm proved to be optimum for increased strength of the crimped terminal connection. Allowing the terminal to protrude 1 mm from the field shaper resulted in a flatter crimped area and significant improvement in the quality of the crimped barrel surface. The empirical formula for calculating the inner diameter vertical dimension of the field shaper is reasonable and reliable, and the calculated measurement resulted in improved connection strength. The results of this research can be used to guide the electromagnetic pulse crimping of other terminal lug and cable types.

Parameter optimization of electromagnetic pulse compaction driven by aluminum tube for tungsten copper powder

Fen-Qiang Li,Juehao Ding,Miao Zheng,Jianlin Xu,Xiaohong Ge,Hui Li,Jun Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

A combination of multi-physics numerical simulation and experiment was conducted to study the magnetic pulse compaction technology driven by two aluminum tubes of tungsten copper powder. Then, the effects of different process parameters on the density and uniformity of the compact were studied by tuning the thickness of the pack and driver tubes and the gap between them. Results show that the density of compact is the highest when the thickness of the driver tube is 1.0 mm. More energy is consumed for force conduction as the thickness of the pack tube increases. Thus, the density of the compact is the highest when the thickness of the packer tube is 0.8 mm. The speed of the driver tube impacting the pack tube also increases with the rise in the gap. Accordingly, the compaction density with the gap of 1.5 mm is the highest under the same other parameters.

Brain-based Correlations Between Psychological Factors and Functional Dyspepsia

( Jiao Fen Nan ),( Ji Xin Liu ),( Jun Ya Mu ),( Wang Huan Dun ),( Ming Zhang ),( Qiyong Gong ),( Wei Qin ),( Jie Tian ),( Fanrong Liang ),( Fang Zeng ) 대한소화기기능성질환·운동학회 2015 Journal of Neurogastroenterology and Motility (JNM Vol.21 No.1

Background/Aims Increasing evidence shows involvement of psychological disorders in functional dyspepsia (FD), but how psychological factors exert their influences upon FD remains largely unclear. The purpose of the present study was to explore the brain-based correlations of psychological factors and FD. Methods Based on Fluorine-18-deoxyglucose positron emission tomography-computed tomography, the altered cerebral glycometabolism was investigated in 40 FD patients compared with 20 healthy controls during resting state using statistical parametric mapping software. Results FD patients exhibited increased glucose metabolism in multiple regions relative to controls (P < 0.001, family-wise error corrected). After controlling for the dyspeptic symptoms, increased aberrations persisted within the insula, anterior cingulate cortex (ACC), middle cingulate cortex (MCC) and middle frontal cortex (midFC), which was related to anxiety and depression score. Interestingly, FD patients without anxiety/depression symptoms also showed increased glycometabolism within the insula, ACC, MCC and midFC. Moreover, FD patients with anxiety/depression symptoms exhibited more significant hypermetabolism within the above 4 sites compared with patients without anxiety/depression symptoms.Conclusions Our results suggested that the altered cerebral glycometabolism may be in a vicious cycle of psychological vulnerabilities and increased gastrointestinal symptoms.

Amphiphilically modified chitosan copolymer for enhanced oil recovery in harsh reservoir condition

Wan-Fen Pu,Rui Liu,Qin Peng,Dai-Jun Du,Qi-Ning Zhao 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.37 No.-

A novel amphiphilically grafting natural chitosan copolymer (PAMCS) was prepared by using one stepwater-free radical polymerization strategy and the basic parameters for PAMCS were systematicallycharacterized. The rigid D-glucosamine unit, intermolecular association and hydrogen bondingsynergistically endowed PAMCS solution with rheological properties, super-high salt resistance andtemperature tolerance in harsh reservoir condition. PAMCS solution exhibited viscoelastic behaviorand formulated the unique displacement mechanism in comparison to that for partially hydrolyzedpolyacrylamide. Moreover, the mass concentration, injective rate and polymer solution slug related to oilrecovery efficiency for PAMCS were investigated from the economic point.