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Kun-Che Ho,Cheng-Chung Lin,F. Selin Bagci,Shun-Chung Wang,Yi-Hua Liu,Yu-Shan Cheng 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
In this study, three swarm intelligence (SI)-based maximum power point tracking (MPPT) techniques for photovoltaic generation systems (PGSs) operating under partially shaded conditions (PSCs) are investigated. The compared methods include particle swarm optimization (PSO), firefly algorithm (FA) and cuckoo search (CS). Simulated results for 252 different shading patterns will be provided and some conclusion will be made. This study presents reference information for scholars planning to carry out research in this field.
Yu, Qi,Lin, Kun,Liu, Yunhui,Li, Xinxing The Korean Neurosurgical Society 2020 Journal of Korean neurosurgical society Vol.63 No.2
Objective : To investigate the efficiency of diffusion tensor imaging (DTI) fiber-tracking based neuronavigation and assess its usefulness in the preoperative surgical planning, prognostic prediction, intraoperative course and outcome improvement. Methods : Seventeen patients with cerebral masses adjacent to corticospinal tract (CST) were given standard magnetic resonance imaging and DTI examination. By incorporation of DTI data, the relation between tumor and adjacent white matter tracts was reconstructed and assessed in the neuronavigation system. Distance from tumor border to CST was measured. Results : The sub-portion of CST in closest proximity to tumor was found displaced in all patients. The chief disruptive changes were classified as follows : complete interruption, partial interruption, or simple displacement. Partial interruption was evident in seven patients (41.2%) whose lesions were close to cortex. In the other 10 patients (58.8%), delineated CSTs were intact but distorted. No complete CST interruption was identified. Overall, the mean distance from resection border to CST was 6.12 mm (range, 0-21), as opposed to 8.18 mm (range, 2-21) with simple displacement and 2.33 mm (range, 0-5) with partial interruption. The clinical outcomes were analyzed in groups stratified by intervening distances (close, <5 mm; moderated, 5-10 mm; far, >10 mm). For the primary brain tumor patients, the proportion of completely resected tumors increased progressively from close to far grouping (42.9%, 50%, and 100%, respectively). Five patients out of seven (71.4%) experienced new neurologic deficits postoperatively in the close group. At meantime, motor deterioration was found in six cases in the close group. All patients in the far and moderate groups received excellent (modified Rankin Scale [mRS] score, 0-1) or good (mRS score, 2-3) rankings, but only 57.1% of patients in the close group earned good outcome scores. Conclusion : DTI fiber tracking based neuronavigation has merit in assessing the relation between lesions and adjacent white matter tracts, allowing prediction of patient outcomes based on lesion-CST distance. It has also proven beneficial in formulating surgical strategies.
Bearing capacity of H-section beam wrapped with ceramsite concrete
Xuechun Liu,Kun Meng,Ailin Zhang,Tao Zhu,Cheng Yu 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.5
In this study, an H-section steel beam with circular holes in a web wrapped with ceramsite concrete (SBWCC) was studied. Static load-bearing capacity tests and finite element analysis were performed on two groups of specimens with different sections. The H-section steel and wrapped ceramsite concrete were well bonded. The load-bearing capacity of the SBWCC was 10% larger than that of the pure H-section steel beam without holes in the web, except for its dead weight. The stiffness of the SBWCC was slightly larger than that of the pure H-section steel beam without holes. The wrapped ceramsite concrete avoided the elastic local instability of the steel beam flange and web. Based on the finite element model verified by experiments, the influences of hole diameter, hole spacing, and U-shaped stirrups on the flexural capacity of the specimens were analyzed. The formulas for the load-bearing capacities and short-term stiffness of the SBWCC were proposed and verified by tests and finite element analysis.
Bin Wang,Kun Wang,Jian Yu,Xiao-meng Hao,Yu-lu Liu,Ai-Yan Xing 한국유방암학회 2022 Journal of breast cancer Vol.25 No.3
Purpose: Neoadjuvant chemotherapy (NAC) is widely used to treat breast cancer (BC). The prediction and evaluation of chemotherapy responses remains a significant challenge. Methods: MicroRNAs (miRNAs) play a crucial role in cancer drug resistance. We used a miRNA microarray and identified that miR-638 is downregulated in chemoresistant cases. However, the exact role of miR-638 and the underlying mechanisms of chemoresistance remain unclear. Using real-time quantitative reverse transcription polymerase chain reaction, we found significant downregulation of miR-638 in chemoresistant patients compared with chemosensitive patients. To explore the function of miR-638, we overexpressed and inhibited miR-638 expression in MDA-MB-231 and MCF-7 cells by transfecting them with miR-638 mimics and miR-638 inhibitor, respectively. Cell proliferation and apoptosis were measured using MTS and flow cytometry, respectively. A minimal patient-derived xenograft (MiniPDX™) model was established to evaluate the chemosensitivity to different drugs. Results: The results showed that cell proliferation decreased and cell apoptosis increased in cells transfected with the miR-638 mimic, and cell proliferation and apoptosis were reversed with transfection of miR-638 inhibitor compared with the control group. Among patients who received 5-fluorouracil (5-FU), miR-638 expression levels were lower in the chemoresistant group than in the chemosensitive group. The MiniPDX™ model showed that MDA-MB-231 cells overexpressing miR-638 were more susceptible to 5-FU treatment in vivo. Conclusion: We provided evidence of acquired resistance to 5-FU caused by miR-638 deficiency. Alterations in miR-638 may be used with 5-FU chemotherapy during NAC for BC.
Zhong Chang Liu,Xing Yuan,Jing Tian,Yong Qiang Han,Kai Bo Yu,Peng Kun Teng 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.5
The object of this paper is to reduce soot emissions under typical 5s transient conditions of constant speed and increasing torque. And effects of fuel injection timing on combustion and emissions parameters were experimentally and numerically studied in a regulated two-stage turbocharged diesel engine with a turbine bypass valve (TBV). The test results indicated that: the smaller TBV opening could improve deterioration of smoke emissions and BSFC at medium and heavy loads. Afterward, the full-stage injection timing (FSIT) strategies (delaying injection timing during the entire transient process) could reduce soot and NOX emissions simultaneously. However, when TBV opening became larger, smoke emissions and BSFC were deteriorated gradually. Moreover, the sectional-stage injection timing (SSIT) strategies (advancing injection timing from 10 % load to a preset load and delaying injection timing from the preset load to 100 % load) could markedly reduce soot emissions by 75.8 % with TBV opening 20 %; the degradation of fuel consumption could be effectively suppressed. Finally, coupling the SSIT strategies with the TBV control strategies could significantly improve the transient performance.
Guo, Chao,Liu, Ye,Yu, Haoran,Du, Kun,Gan, Yiru,Huang, He The Korean Society for Microbiology and Biotechnol 2016 Journal of microbiology and biotechnology Vol.26 No.7
The Ω-loop is a nonregular and flexible structure that plays an important role in molecular recognition, protein folding, and thermostability. In the present study, molecular dynamics simulation was carried out to assess the molecular stability and flexibility profile of the porcine trypsin structures. Two Ω-Loops (fragment 57-67 and fragment 78-91) were confirmed to represent the flexible region. Subsequently, glycosylation site-directed mutations (A73S, N84S, and R104S) were introduced within the Ω-loop region and its wing chain based on its potential N-glycosylation sites (Asn-Xaa-Ser/Thr consensus sequences) and structure information to improve the thermostability of trypsin. The result demonstrated that the half-life of the N84S mutant at 50℃ increased by 177.89 min when compared with that of the wild-type enzyme. Furthermore, the significant increase in the thermal stability of the N84S mutant has also been proven by an increase in the T<sub>m</sub> values determined by circular dichroism. Additionally, the optimum temperatures of the wild-type enzyme and the N84S mutant were 75℃ and 80℃, respectively. In conclusion, we obtained the thermostability-improved enzyme N84S mutant, and the strategy used to design this mutant based on its structural information and N-linked glycosylation modification could be applied to engineer other enzymes to meet the needs of the biotechnological industry.
The Effect of Hygrothermal Aging on the Properties of Epoxy Resin
Wang, Youyuan,Liu, Yu,Xiao, Kun,Wang, Can,Zhang, Zhanxi The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2
Because of excellent electrical properties, epoxy resin is widely used in packaging and casting power equipment. Moisture and temperature in the environment are inclined to seriously affect the insulation tolerance of epoxy resin. This work focuses on the aging characteristics of epoxy resin in hygrothermal environment. Scanning electron microscopy images show that there are micro-crack, micro-slit and holes inside aged samples. The moisture absorption process undergoes three equilibrium stages and it does not follow the Fick's second law. Observing the change of hydrogen bonds in the infrared spectra of the dried samples, it is found that chemically moisture absorption immerges when the physical moisture absorption entered the third equilibrium stage. By Debye equation to fit the imaginary part of the dielectric constant, it is concluded that the uniformity of water molecule has a great influence on the electrical conductivity loss. Furthermore, the polarization loss can be more easily affected by water molecules than small free molecules. After the aged samples being dried, their real and imaginary part of the dielectric constant descend, but their original electrical properties cannot completely restored. After chemical moisture absorption appears inside the material, the residual space charges increase significantly and the charge dissipation rate slow down obviously.