Potential Difference of Cyclic Polarization Curve of an Aircraft Al Alloy: ∆E (E_sec,corr - E_corr)

Sun, Qingqing,Chen, Kanghua The Korean Electrochemical Society 2020 Journal of electrochemical science and technology Vol.11 No.2

This paper presents a hypothesis and its experimental validation that ∆E (E_sec,corr - E_corr) of cyclic polarization curve of an Al-Zn-Mg-Cu alloy decreases firstly and then increases with the increasing of corrosion rate or corroded fraction F_corr of alloy surface. The minimum value of ∆E is obtained when F_corr ≈ 50%. In addition, a proportional relationship between ∆E and |50% - F_corr| was found. This non-monotonic relation between ∆E and extent of localized corrosion indicates that additional attention should be paid on using ∆E to assess localized corrosion behaviour of Al-Zn-Mg-Cu alloys.

LCL-T resonant network-based modular multi-channel constant-current LED driver analysis and design

He, Qingqing,Luo, Quanming,Huang, Jian,Cao, Chi,Sun, Pengju,Du, Xiong The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.6

Multiple output LED drivers are necessary to achieve better performance and higher reliability in street lighting, tunnel lighting and LCD background lighting applications. Based on LCL-T constant-current characteristics, a modular multiple output LED driver is proposed in this paper. The LCL-T rectifiers are connected to the same voltage bus and work like current sources. However, since there are much higher voltage harmonics in the AC square bus voltage, it is very important to quantitatively analyze how these harmonics influence the precision of the output currents. In addition, all of the switches can achieve Zero Voltage Switching (ZVS) by proper design of the LCL-T network. Finally, a 200-W prototype with five channels is established with an efficiency of 92.25%.

Adaptive Virtual Impedance of Grid-Tied Inverters to Enhance the Stability in a Weak Grid

Yan Du,Qingqing Sun,Xiangzhen Yang,Linbo Cui,Jian Zhang,Fei Wang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3

In a weak grid, especially with a grid-voltage proportional feedforward controller, the grid-tied inverter tends to interact with the grid impedance and thus suff ers from poor power quality and even instability. In order to improve the stability, serial-parallel virtual impedance based on the derivative controllers of grid current and voltage is proposed in this paper. With the aim of optimizing the performance of the inverter for a variety of grid impedance, these derivative coeffi cients are adaptively tuned by the constraint of a minimum leading phase which is determined by the phase margin and the current tracking response. With this proposed adaptive virtual impedance, the grid-tied inverter can operate stably under a wide variety of grid impedance and voltage harmonic rejection performance is also improved. Simulation and experimental results validate the eff ectiveness of the proposed method and design methodology.

Increased Piezo1 channel activity in interstitial Cajal-like cells induces bladder hyperactivity by functionally interacting with NCX1 in rats with cyclophosphamide-induced cystitis

Qian Liu,Bishao Sun,Jiang Zhao,Qingqing Wang,Fan An,Xiaoyan Hu,Zhenxing Yang,Jie Xu,Mingjia Tan,Longkun Li 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

The Piezo1 channel is a mechanotransduction mediator, and Piezo1 abnormalities have been linked to several clinical disorders. However, the role of the Piezo1 channel in cystitis-associated bladder dysfunction has not been documented. The current study aimed to discover the functional role of this channel in regulating bladder activity during cyclophosphamide (CYP)-induced cystitis. One hundred four female rats were randomly assigned to the control, CYP-4h, CYP-48h and CYP-8d groups. CYP successfully induced acute or chronic cystitis in these rats. CYP treatment for 48h or 8d significantly increased Piezo1 channel expression in bladder interstitial Cajal-like cells (ICC-LCs), and the increase in CYP-8d rats was more prominent. In addition, 2.5 μM Grammostola spatulata mechanotoxin 4 (GsMTx4) significantly attenuated bladder hyperactivity in CYP-8d rats by inhibiting the Piezo1 channel in bladder ICCLCs. Furthermore, by using GsMTx4 and siRNA targeting the Piezo1 channel, we demonstrated that hypotonic stressinduced Piezo1 channel activation significantly triggered Ca2+ and Na+ influx into bladder ICC-LCs during CYPinduced chronic cystitis. In addition, the Piezo1 channel functionally interacted with the relatively activated reverse mode of Na+/Ca2+ exchanger 1 (NCX1) in bladder ICC-LCs from CYP-8d rats. In conclusion, we suggest that the functional role of the Piezo1 channel in CYP-induced chronic cystitis is based on its synergistic effects with NCX1, which can significantly enhance [Ca2+]i and result in Ca2+ overload in bladder ICC-LCs, indicating that the Piezo1 channel and NCX1 are potential novel therapeutic targets for chronic cystitis-associated bladder hyperactivity.

DHX collector for recovery of cassiterite: Mechanistic insights and practical implications

Yang Cao,Lei Sun,Qingqing Wang,Xin Wang,Yi Qiao,Wei Sun 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.127 No.-

This study addresses the efficiency and sustainability of tin resource utilization by exploring a novel collector,C16H33NO2 (DHX), in cassiterite flotation. DHX demonstrated superior collection efficiency and abroader effective pH range in micro-flotation tests. A peak cassiterite recovery of 92.2% was achievedwith DHX at pH 7.5 ± 0.3, while BHA could achieve only 69.6%. Furthermore, DHX consistently maintaineda recovery above 70% in a wide pH range from 3 to 11. The capacity of DHX to separate cassiteritefrom calcite in mixtures underlines its remarkable selectivity. Zeta potential and contact angle measurementsshowed strong DHX adsorption on cassiterite surfaces, leading to marked enhancements inhydrophobicity and potentially augmenting flotation efficiency. FTIR and XPS analyses further confirmedthe formation of a stable ring structure between the hydroxy and oxime groups in DHX anions and Snions on the cassiterite surface. In practical applications, such as a copper-zinc-tin polymetallic mine inYunnan, China, DHX exhibited promising recovery results in gravity separation tailings. Bench-scaleflotation tests on tin-bearing tailings (0.21% Sn) resulted in a concentrate with a tin grade and recoveryrate of 2.15% and 61.27%, respectively. These results highlight DHX’s immense potential as a cassiteriteflotation collector, outperforming conventional alternatives in performance.

Cyclophosphamide-induced HCN1 channel upregulation in interstitial Cajal-like cells leads to bladder hyperactivity in mice

Qian Liu,Zhou Long,Xingyou Dong,Teng Zhang,Jiang Zhao,Bishao Sun,Jingzhen Zhu,Jia Li,Qingqing Wang,Zhenxing Yang,Xiaoyan Hu,Longkun Li 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are confirmed to be expressed in bladder interstitial Cajal-like cells (ICC-LCs), but little is known about their possible role in cystitis-associated bladder dysfunction. The present study aimed to determine the functional role of HCN channels in regulating bladder function under inflammatory conditions. Sixty female wild-type C57BL/6J mice and sixty female HCN1-knockout mice were randomly assigned to experimental and control groups, respectively. Cyclophosphamide (CYP)-induced cystitis models were successfully established in these mice. CYP treatment significantly enhanced HCN channel protein expression and Ih density and significantly altered bladder HCN1 channel regulatory proteins. Carbachol (CCH) and forskolin (FSK) exerted significant effects on bladder ICC-LC [Ca2+]i in CYP-treated wild-type (WT) mice, and HCN1 channel ablation significantly decreased the effects of CCH and FSK on bladder ICC-LC [Ca2+]i in both naive and CYP-treated mice. CYP treatment significantly potentiated the spontaneous contractions and CCH (0.001–10 μM)-induced phasic contractions of detrusor strips, and HCN1 channel deletion significantly abated such effects. Finally, we demonstrated that the development of CYP-induced bladder overactivity was reversed in HCN1 / mice. Taken together, our results suggest that CYP-induced enhancements of HCN1 channel expression and function in bladder ICC-LCs are essential for cystitis-associated bladder hyperactivity development, indicating that the HCN1 channel may be a novel therapeutic target for managing bladder hyperactivity.

Antisense oligodeoxynucleotides against dynamin-related protein 1 reduce remifentanilinduced hyperalgesia by modulating spinal N-methyl-D-aspartate receptor expression in rats

Songyi Zhou,Yizhao Pan,Yan Zhang,Lijun Gu,Leikai Ma,Qingqing Xu,Weijian Wang,Jiehao Sun 대한통증학회 2023 The Korean Journal of Pain Vol.36 No.3

Background: Spinal N-methyl-D-aspartate (NMDA) receptor activation is attributed to remifentanil-induced hyperalgesia (RIH). However, the specific mechanism and subsequent treatment is still unknown. Previous studies have shown that the dynamin-related protein 1 (DRP1)-mitochondria-reactive oxygen species (ROS) pathway plays an important role in neuropathic pain. This study examined whether antisense oligodeoxynucleotides against DRP1 (AS-DRP1) could reverse RIH. Methods: The authors first measured changes in paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) at 24 hours before remifentanil infusion and 4, 8, 24, and 48 hours after infusion. The expression levels of DRP1 and NR2B were measured after behavioral testing using Western blotting. In addition, DRP1 expression was knocked down by intrathecal administration of AS-DRP1 to investigate the effects of DRP1 on RIH. The behavioral testing, the expression levels of spinal DRP1 and NR2B, and dorsal mitochondrial superoxide were measured. Changes in mitochondrial morphology were assessed using electron microscopy. Results: After remifentanil exposure, upregulation of spinal DRP1 and NR2B was observed along with a reduction in PWMT and PWTL. In addition, AS-DRP1 improved RIH-induced PWTL and PWMT (P < 0.001 and P < 0.001) and reduced remifentanil-mediated enhancement of spinal DRP1 and NR2B expression (P = 0.020 and P = 0.022). More importantly, AS-DRP1 reversed RIH-induced mitochondrial fission (P = 0.020) and mitochondrial superoxide upregulation (P = 0.031). Conclusions: These results indicate that AS-DRP1 could modulate NMDA receptor expression to prevent RIH through the DRP1-mitochondria-ROS pathway.