Effects of Precipitate Element Addition on Microstructure and Magnetic Properties in Magnetostrictive Fe<SUB>83</SUB>Ga<SUB>17</SUB> alloy

Jiheng Li,Chao Yuan,Wenlan Zhang,Xiaoqian Bao,Xuexu Gao 한국자기학회 2016 Journal of Magnetics Vol.21 No.1

The 〈100〉 oriented Fe83Ga17 alloys with various contents of NbC or B were prepared by directionally solidification method at the growth rate of 720 ㎜·h<SUP>−1</SUP>. With a small amount of precipitates, the columnar grains grew with cellular mode during directional solidification process, while like-dendrite mode of grains growth was observed in the alloys with higher contents of 0.5 at% due to the dragging effect of precipitates on the boundaries. The NbC precipitates disperse both inside grains and along the boundaries of Fe83Ga17 alloys with NbC addition, and the Fe₂B secondary phase particles preferentially distribute along the grain boundaries in B-doped alloys. Precipitates could affect grain growth and improved the 〈100〉 orientation during directional solidification process. Small amount of precipitate element addition slightly increased the magnetostrictive strain, and a high value of 335 ppm under pre-stress of 15 ㎫ was achieved in the alloys with 0.1 at% NbC. Despite the fact that the effect on magnetic induction density of small amount of precipitates could be negligible, the coercivity markedly increased with addition of precipitate element for Fe83Ga17 alloy due to the retarded domain motion resulted by precipitates.

Comparison of Unilateral Biportal Endoscopy Decompression and Microscopic Decompression Effectiveness in Lumbar Spinal Stenosis Treatment: A Systematic Review and Meta-analysis

Junjie Li,Jiheng Yin,Jun Liu,haixiong Lin,Haifeng Yuan 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.2

This study aimed to compare the safety and effectiveness between unilateral biportal endoscopy (UBE) technique and microscopic decompression (MD) technique in lumbar spinal stenosis treatment. PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure, and other databases were used to conduct extensive literature searches. RevMan ver. 5.3 software was used for the statistical analysis. Eleven studies were included with 930 patients, including 449 patients in the UBE group and 521 in the MD group. Both techniques revealed similar operative times at −1.77 minutes (95% confidence interval [CI], −7.59 to 4.05 minutes; p =0.55), the postoperative dural expansion area at −1.27 (95% CI, −19.30 to 16.77; p =0.89), the postoperative complications at 0.76 (95% CI, 0.47 to 1.22; p =0.26), the preoperative Visual Analog Scale (VAS) for leg pain, and the last follow-up (>12 months) VAS for leg pain at −0.04 (95% CI, −0.14 to 0.06; p =0.47), the preoperative Oswestry Disability Index (ODI), and the last follow-up (>12 months) ODI scores at −0.18 (95% CI, −0.76 to 0.40; p =0.54), and patient satisfaction (the modified MacNab score) at 1.15 (95% CI, 0.54 to 2.42; p =0.72). However, intraoperative bleeding was lower following the UBE technique at −52.78 mL (95% CI, −93.47 to −12.08 mL; p =0.01) and was shorter following the UBE technique at −3.06 (95% CI, −3.84 to −2.28; p <0.01). UBE and MD technology have no significant differences in efficacy or safety in the treatment of patients with lumbar spinal stenosis based on this meta-analysis. However, the UBE technique has less intraoperative bleeding and a shorter hospital stay. It has a slight advantage and is a better surgical option than the MD technique. It can be an alternative minimally invasive spinal surgery method.

Effects of NaCl on the rheological behavior of collagen solution

Lian Duan,Jiheng Li,Conghu Li,Guoying Li 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.3

The effects of NaCl on the rheological properties of collagen solutions were studied by steady shear test and thixotropic loop test. The results showed the rheological properties of the collagen solutions with different NaCl concentrations were quite different. With low NaCl concentrations (0 to 0.1 mol/L), the collagen solutions exhibited salting in effect. The pseudoplastic behavior of the solutions became weak, while the thixotropy became strong. The collagen solutions with high NaCl concentrations (0.1 to 0.3 mol/L) exhibited salting out effect. The pseudoplastic behavior of the solutions became strong and the thixotropy had no obvious variation. In addition, Ostwald de-waele model, Carreau model and Herschel-Bulkley model were used to fit the experimental data. The superimposed experimental data and the model curves indicated the suitability of the models used, except for the up curves in thixotropic loop test.

Effect of Interfacial Blocking Layer Morphology on the Solar Peroxydisulfate Production of WO₃ Nanoflakes

Ahn, Sung Hoon,Zhao, Jiheng,Kim, Jong Hak,Zheng, Xiaolin Pergamon Press 2017 Electrochimica Acta Vol. No.

<P><B>Abstract</B></P> <P>Herein, we investigate the morphological effect of WO<SUB>3</SUB> interfacial blocking layer on the PEC performance of WO<SUB>3</SUB> nanoflakes grown on fluorine-doped tin oxide (FTO) glass as a model photoanode system. We found that the mesoporous WO<SUB>3</SUB> interfacial blocking layer is much more effective than the random WO<SUB>3</SUB> nanoparticle interfacial layer in reducing the interfacial recombination. With the mesoporous interfacial blocking layer, the photocurrent density of WO<SUB>3</SUB> photoanode reaches 2.6mAcm<SUP>−2</SUP> at 1.23V vs RHE. This PEC system in 1 M H<SUB>2</SUB>SO<SUB>4</SUB> solution produces high-value added peroxydisulfate (S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>) and hydrogen efficiently at over ∼95% faradaic efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The pivotal role of interfacial layer in photoelectrochemical cells is investigated. </LI> <LI> Amphiphilic graft copolymer self-assembly is used as a sacrificial template. </LI> <LI> The continuous WO<SUB>3</SUB> interfacial layer is combined to nanoflakes grown on top. </LI> <LI> The interfacial properties are found to be significantly enhanced. </LI> <LI> This PEC system efficiently produces peroxydisulfate (S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>) and hydrogen. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effects of NaCl on the rheological behavior of collagen solution

Duan, Lian,Li, Jiheng,Li, Conghu,Li, Guoying 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.3

The effects of NaCl on the rheological properties of collagen solutions were studied by steady shear test and thixotropic loop test. The results showed the rheological properties of the collagen solutions with different NaCl concentrations were quite different. With low NaCl concentrations (0 to 0.1 mol/L), the collagen solutions exhibited salting in effect. The pseudoplastic behavior of the solutions became weak, while the thixotropy became strong. The collagen solutions with high NaCl concentrations (0.1 to 0.3 mol/L) exhibited salting out effect. The pseudoplastic behavior of the solutions became strong and the thixotropy had no obvious variation. In addition, Ostwald de-waele model, Carreau model and Herschel-Bulkley model were used to fit the experimental data. The superimposed experimental data and the model curves indicated the suitability of the models used, except for the up curves in thixotropic loop test.

Novel fuzzy direct torque control based on constructed functional transformed grey model

Zhao, Wei,Li, Zhizhong,Xu, Jiheng,Zhang, Haitao,Yuan, Yuan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.6

To reduce the ripple of the magnetic flux and torque of motors and the reduce the hysteresis in motor speed control, an improved grey model predictive fuzzy direct torque control (DTC) method based on function transformation is proposed. First, a function transformation is used to transform the sampled sequences to nonnegative values. This overcomes the disadvantages caused by fluctuant and random sampling of the motor torque and stator flux linkage. Second, an equal dimensional new information model is used to keep the dimensions unchanged, which reduces the time to predict the motor parameters through the model. Moreover, the voltage space vector plane is divided into six sectors, which simplifies the fuzzy control system rules. Simulation results show that the proposed fuzzy direct torque control based on the improved grey model method reduces the influence of hysteresis on the control system, decreases the motor flux chain and torque ripple, improves the response speed of the torque and rotational speed, reduces overshoot, achieves good effects in terms of anti-interference capability and dynamic response, and improves the real-time performance and accuracy of the fuzzy control system.

Epitaxial growth of WO₃ nanoneedles achieved using a facile flame surface treatment process engineering of hole transport and water oxidation reactivity

Shi, Xinjian,Cai, Lili,Choi, Il Yong,Ma, Ming,Zhang, Kan,Zhao, Jiheng,Kim, Jung Kyu,Kim, Jong Kyu,Zheng, Xiaolin,Park, Jong Hyeok The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.40

<P>Charge carrier dynamics and light harvesting ability are most important for the performance of a photoanode in photoelectrochemical (PEC) systems. In this work, through a facile flame surface treatment process in a reducing atmosphere, oriented WO3 nanoneedles are grown on pre-formed vertically aligned nanohelices. Nanohelices have excellent light harvesting abilities on their own; however, the addition of nanoneedles to the top of nanohelices increases the light harvesting abilities even further. More importantly, the reducing atmosphere for the post-treatment process enhances the metallic properties of WO3, changes the band position to facilitate hole transport, and modifies the flat band potential, all of which contribute to an improved performance in terms of photocurrent density and onset. The as-fabricated WO3 nanohelices/nanoneedles with a metallic interface have also been used for heterojunction photoanode fabrication for water oxidation through two- and four-electron pathways for H2O2 and O2 production, respectively.</P>